Giancarlo Paganelli's "Cone Shells" site (see entries for 26 September and 12 May, 1999),
http://www.geocities.com/coneshells
has been updated. The Collection now contains 235 images of cone shells, 16 images of fossil cones,
an extensive Bibliography and useful Links to other cone shell related sites.
Added reference to 'Toto' Olivera's thought-provoking review in
Annals of the New York Academy of Sciences volume on "Molecular Strategies in Biological
Evolution", Edited by Lynn Helena Caporale (Consultant, New York City), published as Proceedings
of a New York Academy of Sciences conference,
June 27-29, 1998.
Outline
This important reference work, the result of a conference co-chaired with Nobel laureate Werner
Arber, addressed the molecular strategies by which lineages of organisms respond to challenges
and opportunities in their environment. It explored the notion that organisms have evolved the
ability to modulate the rate, location, and extent of genetic variation. Jumps in efficiency,
made possible by development of novel, efficient evolutionary strategies, could fuel rapid,
saltatory expansion of species into novel niches as each innovation evolves. An up-to-date
assessment is provided on biochemical mechanisms available to modulate the rate of genetic
change at specific sites within a genome, the induction in certain environments of enzymes
with altered sequence-dependent recombination, mismatch repair and/or replication fidelity,
and statistical evidence for non-random genetic events. This discussion of genomic strategies
for evolution has profound implications for basic biology and evolutionary theory. The subjects
explored are important ones in understanding inherited diseases, tumor progression, and the
challenges posed by pathogenic organisms.
Olivera, B.M., Walker, C., Cartier, G.E., Hooper, D., Santos, A.D., Schoenfeld, R.,
Shetty, R., Watkins, M., Bandyopadyuay, P. and Hillyard, D.R.(1999) "Speciation of Cone Snails
and Interspecific Hyperdivergence of their Venom Peptides: Potential Evolutionary Significance
of Introns". Ann. N.Y. Acad. Sci. 870:
223-237.
Abstract "All 500 species of cone snails (Conus) are venomous predators. From
a biochemical / genetic perspective, differences among Conus species may be based on
the 50-100 different peptides in the venom of each species. Venom is used for prey capture as
well as for interactions with predators and competitors. The venom of every species has its own
distinct complement of peptides. Some of the interspecific divergence observed in venom
peptides can be explained by differential expression of venom peptide superfamilies in
differnet species and of peptide superfamily branching in various Conus lineages into
pharmacologic groups with different targeting specificity. However, the stiking interspecific
divergence of peptide sequences is the dominant factor in the differences observed between
venoms. The small venom peptides (typically 10-35 amino acids in length) are processed from
larger prepropeptide precursors (ca. 100 amino acids). If interspecific comparisons are made
between homologous prepropeptides, the three different regions of a Conus peptide
precursor (signal sequence, pro-region. mature peptide) are found to have diverged at remarkably
different rates. Analysis of synonymous and nonsynonymous substitution rates for the different
segments of a prepropeptide suggests that mutation frequency varies by over an order of
magnitude across the segments, with the mature toxin region undergoing the highest rate. The
three sections of the prepropeptide which exhibit apparently different mutation rates are
separated by introns. This striking segment-specific rate of divergence of Conus
prepropeptide suggests a role for introns in evolution: exons separated by introns have the
potential to eveolve very different mutation rates. Plausible mechanisms that could underlie
differing mutational frequency in the different exons of a gene are discussed .
20 December 1999
Added three references on the selectivity of alpha-Conotoxin
PnIA/PnIB (from the molluscivorous cone snail Conus pennaceus) for the
mammalian neuronal-type nicotinic acetylcholine receptor.
Broxton, N., Miranda, L., Gehrmann, J., Down, J., Alewood, P. and Livett, B.(1999)
"Leu 10 of alpha-conotoxin PnIB confers potency for the neuronal nicotinic
responses in bovine chromaffin cells". Europ. J. Pharmacol. (In-Press).
Abstract "Two alpha-conotoxins PnIA and PnIB (previously reported as being
"mollusc specific") which differ in only two amino acid residues (AN versus LS at residues 10
and 11, respectively), show markedly different inhibition of the neuronal nicotinic
acetylcholine receptor response in bovine chromaffin cells, a mammalian preparation. Whereas
alpha-conotoxin PnIB completely inhibits the nicotine-evoked catecholamine release at 10 uM,
with IC50= 0.7 uM, alpha-conotoxin PnIA is some 30-40 times less potent. Two peptide analogues,
[A10L]PnIA and [N11S]PnIA were synthesized to investigate the extent to which each residue
contributes to activity. [A10L]PnIA (IC50=2.0uM) completely inhibits catecholamine release at
10 uM whereas [N11S]PnIA shows little inhibition. In contrast, none of the peptides inhibit
muscle-type nicotinic responses in the rat hemi-diaphragm preparation. We conclude that the
enhanced potency of alpha-conotoxin PnIB over alpha-conotoxin PnIA in the neuronal-type
nicotinic response is principally determined by the larger, more hydrophobic leucine residue
at position 10 in alpha-conotoxin PnIB."
Hogg, R.C., Miranda, L.P., Craik, D.J., Lewis, R.J., Alewood, P.F. and Adams, D.J.(1999)
"Single amino acid substitutions in alpha-Conotoxin PnIA shift selectivity for subtypes of the
mammalian neuronal nicotinic acetylcholine receptor"
J.Biol.Chem. 274: 36559-36564.
Abstract "The alpha-conotoxins, a class of nicotinic acetylcholine receptor (nAChR) antagonists, are emerging as important probes of
the role played by different nAChR subtypes in cell function and communication. In this study, the native alpha-conotoxins
PnIA and PnIB were found to cause concentration-dependent inhibition of the ACh-induced current in all rat
parasympathetic neurons examined, with IC(50) values of 14 and 33 nM, and a maximal reduction in current amplitude of
87% and 71%, respectively. The modified alpha-conotoxin [N11S]PnIA reduced the ACh-induced current with an IC(50)
value of 375 nM and a maximally effective concentration caused 91% block. [A10L]PnIA was the most potent inhibitor,
reducing the ACh-induced current in ~80% of neurons, with an IC(50) value of 1.4 nM and 46% maximal block of the total
current. The residual current was not inhibited further by alpha-bungarotoxin, but was further reduced by the
alpha-conotoxins PnIA or PnIB, and by mecamylamine. (1)H NMR studies indicate that PnIA, PnIB, and the analogues,
[A10L]PnIA and [N11S]PnIA, have identical backbone structures. We propose that positions 10 and 11 of PnIA and
PnIB influence potency and determine selectivity among alpha7 and other nAChR subtypes, including alpha3beta2 and
alpha3beta4. Four distinct components of the nicotinic ACh-induced current in mammalian parasympathetic neurons have
been dissected with these conopeptides".
Luo, S., Nguyen, T.A., Cartier, G.E., Olivera, B.M., Yoshikami, D. and McIntosh, J.M. (1999)
"Single-residue alteration in alpha-conotoxin PnIA switches its nAChR subtype selectivity".
Biochemistry 38:14542-14548 Abstract "alpha-Conotoxins are disulfide-rich peptides that are competitive antagonists of nicotinic acetylcholine receptors (nAChRs).
Despite their small size, different alpha-conotoxins are able to discriminate among different subtypes of mammalian nAChRs.
In this report, the activity of two peptides from the venom of Conus pennaceus, alpha-conotoxins PnIA and PnIB, are
examined. Although the toxins differ in only two residues, PnIA preferentially blocks alpha3beta2 nAChRs, whereas PnIB
prefers the alpha7 subtype. Point mutation chimeras of these alpha-conotoxins were synthesized and their activities assessed
on Xenopus oocytes expressing specific nAChRs. Change of a single residue, Ala10 to Leu, in PnIA (to form PnIA [A10L])
converts the parent peptide from alpha3beta2-preferring to alpha7-preferring; furthermore, PnIA [A10L] blocks the alpha7
receptor with an IC(50) (12.6 nM) that is lower than that of either parent peptide. Kinetic analysis indicates that differences
in affinity among the analogues are primarily due to differences in off-rate, with PnIA [A10L]'s interaction with alpha7 having
the smallest off-rate (k(off) = 0.17 min(-)(1)). Thermodynamic analysis indicates that Leu10 enhances the peptide's
interaction with alpha7, but not alpha3beta2, receptors, whereas Ser11 (in PnIA [N11S]) reduces its affinity for both alpha7
and alpha3beta2 nAChRs".
17 December 1999
Added a reference from Bruce Furie's research group on the role of
hydrophobic amino acids in precursor function in Conus textile.
Bush, K.A., Stenflo, J., Roth, D.A., Czerwiec, E., Harrist, A., Begley, G.S., Furie, B.C.
and Furie, B. (1999). Hydrophobic amino acids define the carboxylation recognition site in
the precursor of the gamma- carboxyglutamic-acid-containing conotoxin epsilon-TxIX from the
marine cone snail Conus textile. Biochemistry 38:14660-14666.
To identify the amino acid sequence of the precursor of the Gla-containing peptide, epsilon-TxIX, from the venom of the
marine snail Conus textile, the cDNA encoding this peptide was cloned from a Conus textile venom duct library. The cDNA of
the precursor form of epsilon-TxIX encodes a 67 amino acid precursor peptide, including an N-terminal prepro-region, the
mature peptide, and four residues posttranslationally cleaved from the C-terminus. To determine the role of the propeptide in
gamma-carboxylation, peptides were designed and synthesized based on the propeptide sequence of the Gla-containing
conotoxin epsilon-TxIX and used in assays with the vitamin K-dependent gamma-glutamyl carboxylase from C. textile
venom ducts. The mature acarboxy peptide epsilon-TxIX was a high K(M) substrate for the gamma-carboxylase. Synthetic
peptides based on the precursor epsilon-TxIX were low K(M) substrates (5 &mgr;M) if the peptides included at least 12
residues of propeptide sequence, from -12 to -1. Leucine-19, leucine-16, asparagine-13, leucine-12, leucine-8 and
leucine-4 contribute to the interaction of the pro-conotoxin with carboxylase since their replacement by aspartic acid
increased the K(M) of the substrate peptide. Although the Conus propeptide and the propeptides of the mammalian vitamin
K-dependent proteins show no obvious sequence homology, synthetic peptides based upon the structure of
pro-epsilon-TxIX were intermediate K(M) substrates for the bovine carboxylase. The propeptide of epsilon-TxIX contains
significant alpha-helix, as estimated by measurement of the circular dichroism spectra, but the region of the propeptide that
plays the dominant role in directing carboxylation does not contain evidence of helical structure. These results indicate that
the gamma-carboxylation recognition site is defined by hydrophobic residues in the propeptide of this conotoxin precursor.
12 December 1999
Updated the list of Conotoxin Patents
to include the following:
WO09954350A1
"Novel Conotoxin Peptides" by Roger Drinkwater, Richard Lewis, Paul Alewood
and Kathy Nielsen, Centre for Drug Design and Development, University of Queensland, Australia.
[An isolated, synthetic or recombinant omega-conotoxin peptide in which the fourth loop between
cysteine residues 5 and 6 comprises SEQ ID NO: 1 (SEQ ID NO: 1 comprises the amino acid sequence
SGTVGR ) or such a sequence which has undergone one or more amino acid substitutions or side chain
modifications, and uses therefor. The invention relates to novel peptides of the omega conotoxin
class and their use as pharmacological tools in any indication where blockage of N-type calcium
channels may be of benefit, for example in the reduction of neuronal damage following ischemia,
production of analgesia, or enhancement of opiate analgesia, in the treatment of schizophrenia,
stimulant induced psychoses, hypertension, inflammation and diseases which cause
bronchoconstriction and in the inbibition of progression of neuropathic pain. Information, IBM
Patent Searcher and WIPO PCT Publications]
5 December 1999
Added two references on cone shell toxins (conotoxins) and their
interactions with potassium ion channels.
Heinrich Terlau, Anna Boccaccio, Baldomero M. Olivera, and Franco Conti (1999) The Block of
Shaker K+ Channels by k-Conotoxin PVIIA Is State Dependent.
J. Gen. Physiol. 114: 125-140.
kappa-conotoxin PVIIA is the first conotoxin known to interact with voltage-
gated potassium channels by inhibiting Shaker-mediated currents. We studied the mechanism of
inhibition and concluded that PVIIA blocks the ion pore with a 1:1 stoichiometry and that
binding to open or closed channels is very different. Open-channel properties are revealed by
relaxations of partial block during step depolarizations, whereas double-pulse protocols
characterize the slower reequilibration of closed-channel binding. In 2.5 mM-[K+]o, the IC50
rises from a tonic value of approximately 50 to approximately 200 nM during openings at 0 mV,
and it increases e-fold for about every 40-mV increase in voltage. The change involves mainly
the voltage dependence and a 20-fold increase at 0 mV of the rate of PVIIA dissociation, but
also a fivefold increase of the association rate. PVIIA binding to Shaker Delta6-46 channels
lacking N-type inactivation or to wild phenotypes appears similar, but inactivation partially
protects the latter from open-channel unblock. Raising [K+]o to 115 mM has little effect on
open-channel binding, but increases almost 10-fold the tonic IC50 of PVIIA due to a decrease by
the same factor of the toxin rate of association to closed channels. In analogy with
charybdotoxin block, we attribute the acceleration of PVIIA dissociation from open channels to
the voltage-dependent occupancy by K+ ions of a site at the outer end of the conducting pore.
We also argue that the occupancy of this site by external cations antagonizes on binding to
closed channels, whereas the apparent competition disappears in open channels if the competing
cation can move along the pore. It is concluded that PVIIA can also be a valuable tool for
probing the state of ion permeation inside the pore.
Esperanza García, Martin Scanlon, and David Naranjo (1999) A Marine Snail Neurotoxin Shares with Scorpion Toxins a Convergent
Mechanism of Blockade on the Pore of Voltage-gated K Channels.J. Gen. Physiol. 114: 141-158.
kappa-Conotoxin-PVIIA (kappa-PVIIA) belongs to a family of peptides derived from a hunting
marine snail that targets to a wide variety of ion channels and receptors. kappa-PVIIA is a
small, structurally constrained, 27-residue peptide that inhibits voltage-gated K channels.
Three disulfide bonds shape a characteristic four-loop folding. The spatial localization of
positively charged residues in kappa-PVIIA exhibits strong structural mimicry to that of
charybdotoxin, a scorpion toxin that occludes the pore of K channels. We studied the mechanism
by which this peptide inhibits Shaker K channels expressed in Xenopus oocytes with the N-type
inactivation removed. Chronically applied to whole oocytes or outside-out patches, kappa-PVIIA
inhibition appears as a voltage-dependent relaxation in response to the depolarizing pulse used
to activate the channels. At any applied voltage, the relaxation rate depended linearly on the
toxin concentration, indicating a bimolecular stoichiometry. Time constants and voltage
dependence of the current relaxation produced by chronic applications agreed with that of rapid
applications to open channels. Effective valence of the voltage dependence, zdelta, is
approximately 0.55 and resides primarily in the rate of dissociation from the channel, while
the association rate is voltage independent with a magnitude of 10(7)-10(8) M-1 s-1, consistent
with diffusion-limited binding. Compatible with a purely competitive interaction for a site in
the external vestibule, tetraethylammonium, a well-known K-pore blocker, reduced kappa-PVIIA's
association rate only. Removal of internal K+ reduced, but did not eliminate, the effective
valence of the toxin dissociation rate to a value <0.3. This trans-pore effect suggests that: (a) as in the alpha-KTx, a positively charged side chain, possibly a Lys, interacts electrostatically with ions residing inside the Shaker pore, and (b) a part of the toxin occupies an externally accessible K+ binding site, decreasing the degree of pore occupancy by permeant ions. We conclude that, although evolutionarily distant to scorpion toxins, kappa-PVIIA shares with them a remarkably similar mechanism of inhibition of K channels.
Linked to Gary Rosenberg's marvelous "Conchatenations" column on the question
Mollusk or Mollusc ?
- [from the September 1999 issue of American Conchologist].
18 November 1999
Search the database for Conus using the
New Entrez Nucleotide Search.
Hint: Click the box to the left of the conotoxin sequence you wish to display, select FASTA from the Pull Down menu and click Display.
Added link to a new issue of Journal of Molluscan Studies
Vol 65, No 41,
November 1999 containing a very interesting paper by Manami Nishi and Alan J Kohn"Radular teeth of Indo-Pacific molluscivorous species of Conus: a comparative analysis"J Mollus Stud 1999
65: 483-497. Nishi and Kohn examined intra- and interspecific variation in radular morphology of 11 species
of Conus, C. ammiralis, C. araneosus, C. bandanus, C. canonicus, C. episcopatus, C. marmoreus,
C. nodulosus, C. omaria, C. pennaceus, C. textile, and C. victoriae, and intra- and interregional
variations in radular morphology of C. pennaceus from three geographic regions. From their results they propose that
qualitative and quantitative radular tooth characters are potentially useful in differentiating species as well as geographic
subspecies and will improve the taxonomic base which currently categorises Conus on the basis of shell morphology
and color pattern.
WO09824462A1 Use of alpha-conotoxin MII to treat disorders resulting from nicotine-stimulated dopamine release. [Use of alpha CTX MII for pharmacological manipulation of nicotinic receptors which have implications for a wide variety of disorders including psychotic, mood, movement and cognitive. WIPO PCT Publication]
WO09921878A1 Interaction of alpha-conotoxin peptides with neuronal nicotinic acetylcholine receptors. [to enable the design of .agr.-4/7 conotoxin peptide analogs and peptide mimetics which demonstrate the same specificity to neuronal nAChR. Such analogs and peptidemimetics are useful as cardiovascular agents and for treating or detecting small-cell lung carcinoma (SCLC). WIPO PCT Publication]
WO09933482A1 Uses of alpha-conotoxin peptides. [treating disorders regulated at neuronal nicotinic acetylcholine receptors. WIPO PCT Publication]
WO09822126A1 Use of conotoxin peptides ImI and MII a cardiovascular agents. [Use of ImI and MII as heart rate regulating agents, blood pressure regulating agents and anti-arrhythmia agents. WIPO PCT Publication]
5969096 Conotoxin peptides. [CTXs that specifically target particular skeletal nAChRs, and NOT neuronal nAChRs]
5965534 Use of .omega.-conotoxin analogs for treating retinal and optic nerve head damage. [Use of w-CTX for prevention / treatment of retinal or optic nerve head damage in humans]
22 October 1999
Two research papers on conotoxins:
Bruce Furie and team report on the presence of a gamma-carboxylation recognition site in
the propeptide of a conotoxin precursor from Conus textile.
Bush, K.A., Stenflo, J., Roth, D.A., Czerwiec, E., Harrist, A., Begley, G., Furie, B.C.
and Furie, B. (1999) Hydrophobic amino acids define the carboxylation recognition site
in the precursor of the gamma-carboxyglutamic-acid-containing conotoxin e-TxIX from the
marine cone snail Conus textile. Biochemistry (IN PRESS).
"Toto" Olivera and his team have a fascinating paper out on a novel group of peptides found
in Conus venoms designated the T-superfamily of conopeptides, that share a consensus
signal sequence and a conserved arrangement of cysteine residues (- -CC- -CC-). Eight peptides
belonging to this superfamily have been identified; three were isolated from the venom and biochemically
characterized, and two have been chemically synthesized (p5a from C. purpurascens
and au5a from C. aulicus).
Walker, C.S., Steel, D., Jacobsen, R.B., Lirazan, M.B., Cruz, L.J., Hooper, D., Shetty, R.,
DelaCruz, R.C., Nielsen, J.S., Zhou, L.M., Bandyopadhyay, P., Craig, A.G. and Olivera, B.M.
The T-superfamily of Conotoxins, J. Biol. Chem. 274: 30664-30671.
7 October 1999
The National Aquarium in Baltimore says it "in a nutshell". Click HERE to read their entry on Cone snail venoms and their medical applications.
2 October 1999
Added a "Gooey" chat facility to this page (see
icon above)
Click on the icon to download "Gooey" so you can chat with others viewing this page at the same time as you are viewing this page.
Added a link to Eddie's Cone Shell Catalogue listing over 500 species of Cone Shells (Conus ) with Taxonomic information [Class: GASTROPODA; Order: CAENOGASTROPODA; Superfamily: CONACEA; Family: CONIDAE; Species: Conus ], Location-Habitat, Literature Reference materials and Images (for those marked *). If you have comments, suggestions, corrections, images then email Eddie Hardie (Hardy's Internet Guide to Marine Gastropods) at jzhhardy@xs4all.nl and he will get back to you after his diving and shelling trip to Zanzibar.
Added a button ..
.. at the top of this page to enable visitors to Recommend this site to colleagues and friends.
20 September 1999
Added link to interesting popular science article in MBL Lab Notes, Fall '97 titled "Of Molluscs and Men" describing work on conotoxins and blood disorders in Bruce Furie's laboratory at The Marine Biological Laboratory (MBL), Woods Hole, Mass, USA.[see also: entry for 13 September, below]
Added reference to a Review Article from Olivera's laboratory on postranslational processing of conopeptides.
Craig, A.G., Bandyopadhyay, P. and Olivera, B.M. (1999)
Review Article:"Post-translationally modified neuropeptides from Conus
venoms" Eur. J. Biochem. 264, 271-275 Abstract: Predatory cone snails (genus Conus) comprise what is arguably
the largest living genus of marine animals (500 species). All Conus use
complex venoms to capture prey and for other biological purposes. Most
biologically active components of these venoms are small disulfide-rich
peptides, generally 7-35 amino acids in length. There are probably of the
order of 100 different peptides expressed in the venom of each of the 500
Conus species.
Peptide sequences diverge rapidly between Conus species, resulting in a
distinct peptide complement for each species. Thus, the genus as a whole
has probably generated 50 000 different peptides, which can be organized
into families and superfamilies with shared sequence elements [3]. In this
minireview, we provide a brief overview of the neuropharmacological,
molecular and cell-biological aspects of the Conus peptides. However, the
major focus of the review will be the remarkable array of
post-translational modifications found in these peptides.
18 September 1999
Added 6 new references on conopeptides:
Pallaghy, P.K., Melnikova, A.P., Jimenez, E.C., Olivera, B.M. and Norton, R.S. (1999) "Solution structure of contryphan-R, a naturally occurring disulfide-bridged octapeptide containing D-tryptophan: comparison with protein loops". Biochemistry 38: 11553-11559 Abstract: Contryphan-R is a disulfide-constrained octapeptide containing a D-tryptophan that was isolated recently from venom of the cone shell Conus radiatus. The polypeptide is present in two forms in solution due to cis-trans isomerization at hydroxyproline 3. The solution structure of the major form of this unusual polypeptide, determined from NMR data, consists of a well-defined fold containing a non-hydrogen-bonded chain reversal from Gly1 to Glu5, which includes a cis-hydroxyproline and a D-Trp, and a type I beta-turn from Glu5 to Cys8. The presence of a putative salt bridge between the Glu5 carboxyl group and the N-terminal ammonium group is investigated by using various solvation models during energy minimization and is compared with the results of a pH titration. A comparison of the structure of contryphan-R with other cyclic peptide structures highlights some of the key structural determinants of these peptides and suggests that the contryphan-R fold could be exploited as a scaffold onto which unrelated protein binding surfaces could be grafted. Comparison with small disulfide-bridged loops in larger proteins shows that contryphan-R is similar to a commonly occurring loop structure found in proteins.
Jacobsen, R.B., Jimenez, E.C., De la Cruz, R.G., Gray W,R., Cruz, L.J. and Olivera, B.M. (1999) "A novel D-leucine-containing Conus peptide: diverse conformational dynamics in the contryphan family" J Pept Res 54: 93-99 Abstract: A Conus peptide family (the contryphans) is noteworthy because of the presence of a post-translationally modified D-amino acid in all members of the family. A new contryphan peptide, Leu-contryphan-P, was isolated from the venom of Conus purpurascens; the sequence of this peptide is: Gly-Cys-Val-D-Leu-Leu-Pro-Trp-Cys-OH. This is the first known occurrence of D-leucine in a Conus peptide. The discovery of Leu-contryphan-P suggests that there may be branches of the contryphan peptide family that diverge much more in sequence than previously anticipated. Several natural contryphans provide dramatic examples of interconversion between multiple conformational states in small constrained peptides. The contryphans that have 4-trans-hydroxyproline and D-tryptophan in positions 3 and 4, respectively, exhibit two peaks under reverse-phase HPLC conditions, indicating interconversion between two discrete conformations. However, [L-Trp4]contryphan-Sm (with L-Trp substituted for D-Trp) exhibits a single, broad peak that elutes later than the natural peptide, suggesting that D-Trp stabilizes a conformation in which hydrophobic residues are buried. Leucontryphan-P which has valine and D-leucine instead of 4-trans-hydroxyproline and D-tryptophan shows only a single peak that elutes much later than the other contryphans.
Le, M.T., Vanderheyden, P.M., De Backer, J.P., Vanquelin, G. and Vanden Broeck, J. (1999) "High affinity displacement of [(3)H]NPY binding to the crude venom of conus anemone by insect neuropeptides" Biochem Biophys Res Commun 262: 180-186 Abstract: The venom from Conus anemone contains a protein, named ANPY toxin, which displayed high affinity (IC(50) in nanomolar range) to neuropeptide Y (NPY), [Leu(31), Pro(34)]NPY, peptide YY, pancreatic polypeptide, the Y(1) antagonist 1229U91, and C-terminal NPY fragments. N-terminal fragments and the free acid form of NPY did not bind to ANPY. The truncated NPY fragments displayed very low affinity to Y(1) receptors and partially inhibited [(3)H]NPY binding to anti-NPY antiserum. Several insect neuropeptides, the sequences of which related to the C-terminal fragments of NPY, were observed to bind with similar affinity or even 20 times higher (Lom-MS and Scg-NPF) affinity than NPY. In contrast, no significant binding of these insect peptides was observed for Y(1) receptors and anti-NPY antiserum. Therefore, ANPY can be viewed as an acceptor that binds with very high affinity to a broad spectrum of vertebrate and invertebrate neuropeptides that share a similar C-terminal amino acid sequence.
Lin, C.H., Chan, F.C., Hwang, J.K., Lyu and P.C. (1999) "Calcium binding mode of gamma-carboxyglutamic acids in conantokins" Protein Eng 12: 589-595 Abstract: Conantokin-T (con-T) and conantokin-G (con-G) are two highly homologous peptide toxins found in Conus venom. The former is a 21-residue peptide with four gamma-carboxyglutamic acid (Gla) residues (at positions 3, 4, 10 and 14), while the latter is a 17-residue peptide with five gamma-carboxyglutamic acid residues (at positions 3, 4, 7, 10 and 14). Despite the apparent similarity in number and relative positions of the gamma-carboxyglutamic acid residues, (113)Cd-NMR studies indicated a distinct metal binding behavior for con-G and con-T. There appears to be four binding sites in con-G in contrast to one metal binding site in con-T. To elucidate the mode of calcium binding by the gamma-carboxyglutamic acid residues in these conantokins, we designed various analogous peptides with their gamma-carboxyglutamic acid replaced by other amino acid residues. (113)Cd-NMR experiments on conantokin analogues reveal that the major difference in the number of metal binding sites between con-G and con-T is due to the residue at position 7. We also performed molecular simulations to calculate the relative binding free energies of several potential binding sites. Based on our theoretical and experimental results, we propose a 'four-site' binding model for conantokin-G and a 'single-site' binding model for conantokin-T.
Olivera, B.M., Walker, C., Cartier, G.E., Hooper, D., Santos, A.D., Schoenfeld, R., Shetty, R., Watkins, M., Bandyopadhyay, P. and Hillyard, D.R. (1999) "Speciation of cone snails and interspecific hyperdivergence of their venom peptides. Potential evolutionary significance of introns.
" Ann N Y Acad Sci 870: 223-237 Abstract: All 500 species of cone snails (Conus) are venomous predators. From a biochemical/genetic perspective, differences among Conus species may be based on the 50-200 different peptides in the venom of each species. Venom is used for prey capture as well as for interactions with predators and competitors. The venom of every species has its own distinct complement of peptides. Some of the interspecific divergence observed in venom peptides can be explained by differential expression of venom peptide superfamilies in different species and of peptide superfamily branching in various Conus lineages into pharmacologic groups with different targeting specificity. However, the striking interspecific divergence of peptide sequences is the dominant factor in the differences observed between venoms. The small venom peptides (typically 10-35 amino acids in length) are processed from larger prepropeptide precursors (ca. 100 amino acids). If interspecific comparisons are made between homologous prepropeptides, the three different regions of a Conus peptide precursor (signal sequence, pro-region, mature peptide) are found to have diverged at remarkably different rates. Analysis of synonymous and nonsynonymous substitution rates for the different segments of a prepropeptide suggests that mutation frequency varies by over an order of magnitude across the segments, with the mature toxin region undergoing the highest rate. The three sections of the prepropeptide which exhibit apparently different mutation rates are separated by introns. This striking segment-specific rate of divergence of Conus prepropeptides suggests a role for introns in evolution: exons separated by introns have the potential to evolve very different mutation rates. Plausible mechanisms that could underlie differing mutational frequency in the different exons of a gene are discussed.
Meadows, H.J. and Benham, C.D. (1999) "Sensitivity to conotoxin block of splice variants of rat alpha 1B (rbBII) subunit of the N-type calcium channel coexpressed with different beta subunits in Xenopus oocytes" Ann N Y Acad Sci 868: 224-227
14 September 1999
Added Jon-Paul Bingham now at the School of Pharmacy, Department of Pharmaceutical Chemistry, Mass Spectrometry Facility , University of California (UCSF), San Francisco, USA to list of folk interested in Conidae. Jon-Paul's specific interest is on novel post-translational modifications of conotoxins and conopeptides, the identification of new sequences, as well as assigning disulfide connectivity to these highly constrained peptides. At present his focus concerns the "biological understanding" and use of the milked venoms from Conus (representing species of piscivore, molluscivore and vermivore species) as a rapid approach to characterize novel activity and assign new toxin squences. He is always interested to meet and chat to fellow researchers who have a keen interest in these novel compounds. He also admits to being "a crazed shell collector (of course specialising in Conidea)".
"Drugs from the peptide venoms of marine cone shells" Lewis, R.J., Bingham, J.P., Jones, A., Alewood, P.F. and Andrews, P.R. (1994)Australas Biotechnol. 4: 298-300 Review.
Abstract: Australian cone shell venoms are being investigated as an exciting new source of bioactive peptides as part of a new collaborative project between the 3D Centre and AMRAD. Initial studies have already revealed a number of new and novel acting peptides amongst the hundred or so small, heavily constrained peptides present in the venom of each cone shell. The aim of the project is to develop peptidomimetic drugs based on a selection of these native peptides.
"Isolation and characterization of conopeptides by high-performance liquid chromatography combined with mass spectrometry and tandem mass spectrometry" Jones, A., Bingham, J.P., Gehrmann, J., Bond, T., Loughnan, M., Atkins, A., Lewis, R.J. and Alewood, P.F. (1996)Rapid Commun Mass Spectrom. 10:138-143
"Three-dimensional solution structure of alpha-conotoxin MII by NMR spectroscopy: effects of solution environment on helicity" Hill, J.M., Oomen, C.J., Miranda, L.P., Bingham, J.P., Alewood, P.F. and Craik, D.J. (1998) Biochemistry 37: 15621-15630 Abstract: alpha-Conotoxin MII, a 16-residue polypeptide from the venom of the piscivorous cone snail Conus magus, is a potent and highly specific blocker of mammalian neuronal nicotinic acetylcholine receptors composed of alpha3 beta2 subunits. The role of this receptor type in the modulation of neurotransmitter release and its relevance to the problems of addiction and psychosis emphasize the importance of a structural understanding of the mode of interaction of MII with the alpha3 beta2 interface. Here we describe the three-dimensional solution structure of MII determined using 2D 1H NMR spectroscopy. Structural restraints consisting of 376 interproton distances inferred from NOEs and 12 dihedral restraints derived from spin-spin coupling constants were used as input for simulated annealing calculations and energy minimization in the program X-PLOR. The final set of 20 structures is exceptionally well-defined with mean pairwise rms differences over the whole molecule of 0.07 A for the backbone atoms and 0.34 A for all heavy atoms. MII adopts a compact structure incorporating a central segment of alpha-helix and beta-turns at the N- and C-termini. The molecule is stabilized by two disulfide bonds, which provide cross-links between the N-terminus and both the middle and C-terminus of the structure. The susceptibility of the structure to conformational change was examined using several different solvent conditions. While the global fold of MII remains the same, the structure is stabilized in a more hydrophobic environment provided by the addition of acetonitrile or trifluoroethanol to the aqueous solution. The distribution of amino acid side chains in MII creates distinct hydrophobic and polar patches on its surface that may be important for the specific interaction with the alpha3beta2 neuronal nAChR. A comparison of the structure of MII with other neuronal-specific alpha-conotoxins provides insights into their mode of interaction with these receptors.
13 September 1999
Added Bruce Furie of Harvard Medical School,Boston MA, and the Marine Biological Laboratory, Woods Hole MA, USA to list of folk interested in Conidae. Bruce is interested in Vitamin K-Dependent gamma-Glutamyl Carboxylase and has published on a gamma-carboxyglutamic acid-containing peptide, conotoxin epsilon-TxIX, isolated from the venom of the molluscivorous cone snail, Conus textile. [see also entry for 20 September, above]
"A conotoxin from Conus textile with unusual posttranslational modifications reduces presynaptic Ca2+ influx", Rigby, A.C., Lucas-Meunier, E., Kalume, D.E., Czerwiec, E., Hambe, B., Dahlqvist, I., Fossier, P., Baux, G., Roepstorff, P., Baleja, J.D., Furie, B.C., Furie, B., and Stenflo, J. (1999) " Proc Natl Acad Sci U S A. 96: 5758-5763
"Role of gamma-carboxyglutamic acid in the calcium-induced structural transition of conantokin G, a conotoxin from the marine snail Conus geographus" Rigby, A.C., Baleja, J.D., Li, L., Pedersen, L.G., Furie, B.C. and Furie, B.(1997) Biochemistry 36: 15677-15684.
"Three-dimensional structure of a gamma-carboxyglutamic acid-containing conotoxin, conantokin G, from the marine snail Conus geographus: the metal-free conformer." Rigby, A.C., Baleja, J.D., Furie, B.C. and Furie, B. (1997) Biochemistry 36: 6906-6914.
7 September 1999
Added reference to the latest Duda & Palumbi paper which contains an evolutionary tree of 70 Conus species based on intron sequence data. Available on-line in the 31 August issue of Proc. Natl. Acad. Sci. (USA) 96 (18),10272-10277, 1999)
: Developmental shifts and species selection in gastropods by Thomas F. Duda Jr. and Stephen R. Palumbi from the Department of Organismic and Evolutionary Biology, Harvard. "The fossil record of marine gastropods has been used as evidence to support the operation of species selection; namely, that species with limited dispersal differentially increase in numbers because they are more likely to speciate than widely dispersing species. This conclusion is based on a tacit phylogenetic assumption that increases in species with limited dispersal are solely the result of speciation within monophyletic groups with low dispersal. To test this assumption, we reconstructed a phylogeny from nuclear sequence data for 70 species of the marine gastropod genus Conus and used it to map the evolution of developmental mode. All eight species without planktonic life history phases recently and independently evolved this characteristic from ancestors with planktonic larval phases, showing that transitions in developmental mode are common in this group. A simple model of species diversification shows that such shifts can control the relative numbers of species with and without dispersing larval stages, leading to apparent species selection. Such results challenge the conclusion that increases in the number of nonplanktonic species relative to species with planktonic larvae over geologic time is necessarily a result of higher rates of speciation of nonplanktonic lineages and show that demonstration of species selection requires a phylogenetic framework. [Thanks to Mike Fainzilber on our ListBot for this information].
Added a Guest Book to the Contact Us page and to this page (see above).
: Use of .alpha.-conotoxin MII to treat disorders resulting from nicotine-stimulated dopamine release.
by J.M. McIntosh, J.M. Kulak, D. Yoshikami and B.M. Olivera). Neuronal nicotinic acetylcholine receptors (nAChRs) are believed to mediate nicotine addiction. In addition, stimulation of nAChRs modulates release of neurotransmitters including dopamine, norepinephrine and serotonin. Thus, pharmacological manipulation of nicotinic receptors has implications for a wide variety of disorders including psychotic, mood, movement and cognitive. Alpha-conotoxin MII, a small peptide from the carnivorous marine snail Conus magus, was recently isolated. This peptide has been shown to be a specific antagonist for .alpha.3 beta2 subtype of neuronal nicotinic receptors. The peptide potently blocks part, but not all, of nicotine-stimulated dopamine release from rat brain striatal synaptosomes. In contrast it has no effect on potassium stimulated dopamine release. What is claimed is: "A method of treating a person with a mood disorder, said method comprising a step of administering an effective amount of .alpha.-conotoxin MII to said person"
patent no. 5922679: Use of .alpha.-conotoxin MII to treat disorders resulting from nicotine-stimulated dopamine release.
by J.M. McIntosh, J.M. Kulak, D. Yoshikami and B.M. Olivera). Pharmacological manipulation of nicotinic receptors has implications for a wide variety of disorders including psychotic, mood, movement and cognitive. Alpha-conotoxin MII, a small peptide from the carnivorous marine snail Conus magus, was recently isolated. This peptide has been shown to be a specific antagonist for .alpha.3 beta2 subtype of neuronal nicotinic receptors. The peptide potently blocks part, but not all, of nicotine-stimulated dopamine release from rat brain striatal synaptosomes. In contrast it has no effect on potassium stimulated dopamine release. What is claimed is: "A method of treating a person with psychosis, said method comprising a step of administering an effective amount of .alpha.-conotoxin MII to said person"
1 September 1999
Added reference on alpha-conotoxin ImI from Conus imperialis showing that this selective and potent inhibitor of the neuronal nicotinic acetylcholine receptor displays two regions essential for bioactivity: the active site Asp(5)-Pro(6)-Arg(7), "DPR", in the first loop and Trp(10) in the second loop. As previously demonstrated by chemical site-directed mutagenesis experiments (Servent et al 1998; Quiram and Sine 1998), three central residues D5, P6, R7 are crucial in the interaction of alpha-ImI with the alpha7 nAChR. Mutations of these residues cause at least two orders of magnitude decrease in affinity. The W10 residue contributed mor moderately to binding activity with a three- and six-fold decrease in activity for W10F and W10A analogs, respectively. The W10T analog had 30-fold reduced affinity emphasizing the necessary presence of an aromatic or hydrophobic side chain at the 10th position in the second loop. Deletion of the Cys(3),Cys(12) disulfide bond in the alpha-ImI scaffold, had no effect on its binding affinity (Servent et al 1998). Other studies revealed a crucial functional role of the Arg(7)side chain. The beta-turn forming property of the 6th residue (Pro) in the active site of ImI can be correlated with its affinity. Other studies have shown that the overall conformation in solution of alpha-ImI deduced from CD data can be assigned as a highly constrained and distorted helix (Maslennikov, 1999; Rogers et al 1999).
Lamthanh, J., Jegou-Matheron, C., Servent, D., Menez, A and Lancelin, J-M (1999) Minimal conformation of the alpha-conotoxin ImI for the alpha7 neuronal nicotinic acetylcholine recognition correlated CD, NMR, and binding studies. FEBS Letters454: 293-298.
Servent, D., Thanh, H.L., Antil, S., Bertrand, D., Corringer, P.J., Changeux, J.P. and Menez, A. (1998) Functional determinants by which snake and cone snail toxins block the alpha 7 neuronal nicotinic acetylcholine receptors. J Physiol Paris. 92(2):107-11.
Maslennikov, I.V., Shenkarev, Z.O., Zhmak, M.N., Ivanov, V.T., Methfessel, C., Tsetlin, V.I. and Arseniev, A.S.(1999)NMR spatial structure of alpha-conotoxin ImI reveals a common scaffold in snail and snake toxins recognizing neuronal nicotinic acetylcholine receptors FEBS Lett. 444: 275-280.
Rogers, J.P., Luginbuhl, P., Shen, G.S., McCabe, R.T., Stevens, R.C. and Wemmer, D.E.
(1999)NMR solution structure of alpha-conotoxin ImI and comparison to other conotoxins specific for neuronal nicotinic acetylcholine receptors. Biochemistry 38(13):3874-82
31 August 1999
George Sangiouloglou has a colourful descriptive Web site entitled Shelling in Palawan" with lots of images and the experience from his last shelling trip (4 April '99) where he collected Conus chaldaeus, ebraeus, frigidus, furvus (pinkish color with lines found only in Palawan), magus, miles, miliaris, monachus, omaria, ratus, and scabriusculus, all on Malonao Is. in the China sea.
7 August 1999
A very attractively illustrated account of cone shells and their toxins is given (in French) in Pour la Science, No. 261, July 1999 -"Pour paralyser leurs proies, ces coquillages utilisent des venins qui contiennent d'innombrables toxines dont l'action est ciblée." The article "Cones et toxines" is authored by Frederic Le Gall, Philippe Favreau and Georges Richard. The article is enhanced with thumbnail images of 15 different cone shells and two images of the barbed harpoon-like raduae from a molluscivorous cone, Conus textile (on the left) and a piscivorous cone, Conus striatus (on the right). A selected bibliography of the authors' recent scientific publications is included.
28 July 1999 The Hawaiian Shell News for July 1999 has reprinted an earlier article by Roland M. Gray "Reminiscences of Diving and Related Activities in Hawaii" written about 1959 about events during the period 1956-1958. Of particular interest is an account of Conus envenomation by Conus textile and by Conus halotropus (now known as Conus obscurus). Makes for interesting reading.
21 July 1999
Updated Resources page to include links to commercial companies with interests in developing conotoxins for therapeutic applications (Elan pharmaceuticals/Neurex Corp; Cognetix Inc; and Xenome Limited).
20 July 1999
Updated the table of Sequences of the alpha-conotoxins by adding links to Protein Information Resource (PIR) data for each conotoxin listed in the table.
[The Protein Information Resource (PIR), in collaboration with the Munich Information Center for Protein Sequences (MIPS) and the Japanese International Protein Sequence Database (JIPID) maintains the PIR-International Protein Sequence Database --- a comprehensive, annotated, and non-redundant set of protein sequence databases in which entries are classified into family groups and alignments of each group are available.]
The above table of conotoxin sequences hotlinks to the server at Georgetown University. The National Biomedical Research Foundation is affiliated with Georgetown University Medical Center.
The PIR-International Protein Sequence Database, Release 61.01, July 16, 1999 Contains: 133537 Entries, 41 of which are to conopeptides (conotoxins, conantokins and precursors). Link here to full complete alphabetized list of all the conus peptides currently in the PIR, with the entry code identifiers. Thanks acknowledged to Dr. John S.Garavelli, Associate Director, PIR, National Biomedical Research Foundation, Washington, DC 20007, USA, for this information and resource.
14 July 1999
Added the following reviews on conotoxins:
Adams, D.J., Alewood, P.F., Craik, D.J., Drinkwater, R.D. and Lewis, R.J. (1999) Conotoxins and their potential pharmaceutical applications. Drug Development Research46: 219-234. [This article reviews current research on conotoxins with a focus on drug potential being developed at the University of Queensland, Australia]
McIntosh, J.M., Santos, A.D. and Olivera, B.M. (1999) Conus peptides targeted to specific nicotinic acetylcholine receptor subtypes. Annual Review of Biochemistry Vol. 68 59-88.
8 July 1999
Conotoxin patents: Updated the list of Conotoxin patents (total now 20)
at http://grimwade.biochem.unimelb.edu.au/cone/conpaten.html (Addition to list - patent no. US05866682: Conopeptides AuIA, AuIB and AuIC by JM McIntosh, GE Cartier, D Yoshikami, S. Luo and BM Olivera). These conotoxins come from Conus aulicus. The patent relates to their paper last year Luo S, Kulak JM, Cartier GE, Jacobsen RB, Yoshikami D, Olivera BM, McIntosh JM (1998) Alpha-conotoxin AuIB selectively blocks alpha3 beta4 nicotinic acetylcholine receptors and nicotine-evoked norepinephrine release. J. Neurosci. 18:8571-8579
7 July 1999
Added the following references on conotoxins:
Gouda, H. and Hirono, S. (1999)"Solution structure of alpha-conotoxin ImI determined by two-dimensional NMR spectroscopy". Biochim Biophys Acta1431: 384-394.[The three-dimensional structure of alpha-conotoxin ImI, a potent antagonist targeting the neuronal alpha7 subtype of nicotinic acetylcholine receptor (nAChR), has been investigated by NMR spectroscopy. On the basis of 181 experimental constraints, a total of 25 converged structures were obtained. The average pairwise atomic root mean square difference is 0.40+/-0.11 A for the backbone atoms. The resulting structure indicates the presence of two successive type I beta-turns and a 310 helix for residues Cys2-Cys8 and Ala9-Arg11, respectively, and shows a significant structural similarity to that of alpha-conotoxin PnIA, which is also selective for the neuronal nAChR.
]
Nielsen, K.J., Adams, D., Thomas, L., Bond, T., Alewood, P.F., Craik, D.J. and Lewis, R.J. (1999)"Structure-activity relationships of omega-conotoxins MVIIA, MVIIC and 14 loop splice hybrids at N and P/Q-type calcium channels". J. Mol Biol289: 1405-1421. [The omega-conotoxins are a set of structurally related, four-loop, six cysteine containing peptides, that have a range of selectivities for different subtypes of the voltage-sensitive calcium channel (VSCC). To investigate the basis of the selectivity displayed by these peptides, we have studied the binding affinities of two naturally occurring omega-conotoxins, MVIIA and MVIIC and a series of 14 MVIIA/MVIIC loop hybrids using radioligand binding assays for N and P/Q-type Ca2+channels in rat brain tissue. A selectivity profile was developed from the ratio of relative potencies at N-type VSCCs (using [125I]GVIA radioligand binding assays) and P/Q-type VSCCs (using [125I]MVIIC radioligand binding assays). In these peptides, loops 2 and 4 make the greatest contribution to VSCC subtype selectivity, while the effects of loops 1 and 3 are negligible. Peptides with homogenous combinations of loop 2 and 4 display clear selectivity preferences, while those with heterogeneous combinations of loops 2 and 4 are less discriminatory.1H NMR spectroscopy revealed that the global folds of MVIIA, MVIIC and the 14 loop hybrid peptides were similar; however, several differences in local structure were identified. Based on the binding data and the 3D structures of MVIIA, GVIA and MVIIC, we have developed a preliminary pharmacophore based on the omega-conotoxin residues most likely to interact with the N-type VSCC. Copyright 1999 Academic Press.
]
Quiram, P.A., Jones, J.J. and Sine, S.M. (1999)"Pairwise interactions between neuronal alpha 7 acetylcholine receptors and alpha-contoxoin ImI" J. Biol Chem 274: 19517-19524. [The present work uses alpha-conotoxin ImI (CTx ImI) to probe the neurotransmitter binding site of neuronal alpha7 acetylcholine receptors. We identify key residues in alpha7 that contribute to CTx ImI affinity, and use mutant cycles analysis to identify pairs of residues that stabilize the receptor-conotoxin complex. We first mutated key residues in the seven known loops of alpha7 that converge at the subunit interface to form the ligand binding site. The mutant subunits were expressed in 293 HEK cells, and CTx ImI binding was measured by competition against the initial rate of 125I-alpha-bungarotoxin binding. The results reveal a predominant contribution by Tyr-195 in alpha7, accompanied by smaller contributions by Thr-77, Tyr-93, Asn-111, Gln-117, and Trp-149. Based upon our previous identification of bioactive residues in CTx ImI, we measured binding of receptor and toxin mutations and analyzed the results using thermodynamic mutant cycles. The results reveal a single dominant interaction between Arg-7 of CTx ImI and Tyr-195 of alpha7 that anchors the toxin to the binding site. We also find multiple weak interactions between Asp-5 of CTx ImI and Trp-149, Tyr-151, and Gly-153 of alpha7, and between Trp-10 of CTx ImI and Thr-77 and Asn-111 of alpha7. The overall results establish the orientation of CTx ImI as it bridges the subunit interface and demonstrate close approach of residues on opposing faces of the alpha7 binding site.
]
Nielsen, K.J., Adams, D.A., Alewood, P.F., Lewis, R.J., Thomas, L., Schroeder, T. and Craik, D.J. (1999)"Effects of chirality at Try13 on the structure-activity relationships of omega-conotoxins from Conus magus". Biochemistry38: 6741-6751. [The effects of chirality inversions of Tyr13 on the structure-activity relationships of omega-conotoxins MVIIA and MVIIC were examined using a combination of 2D 1H NMR spectroscopy and radioligand binding studies specific for N-type ([125I]GVIA) and P/Q-type ([125I]MVIIC) voltage-sensitive calcium channels (VSCCs). A comparison of the Halpha secondary shifts suggests that the structural scaffolds of MVIIA and MVIIC are little altered by the L- to D- inversion of Tyr13; however, the conformations of several residues in loop 2 (residues 9-14) are significantly altered. The experimentally determined 3D structure of [D-Y13]MVIIA indicates that the positions of key residues in this loop which are involved in the binding of MVIIA to the N-type VSCC (Tyr13, Arg10, and Leu11) are so changed as to render the peptide unrecognizable by its cognate ion channel. The large reduction in potency observed for MVIIA and MVIIC at both N-type and P/Q-type VSCCs is likely to stem from the change in conformation and orientation of loop 2.
]
6 July 1999
From the Archive:
'Ghoulish' Potion Shows Nervous System Function' The Stetten Lecture NIH Record, 10/08/96. Dr. Baldomero M. Olivera, distinguished professor of biology at the University of Utah, describes how a potent venom, found in marine snails, helps to reveal molecular mechanisms underlying nervous system function.
'Chemical in Snail Venom Kills Chronic Pain'
Inside Science TV News, May 20, 1998. In this transcript, Dr. George Miljanich, Senior Director of Biochemistry and Paul Goddard, Chairman & CEO, Neurex Corp., together with Barry Roysdon, clinical trial patient with chronic pain, are interviewed by Randy Atkins about the new drug, Ziconotide, developed from the cone shell venom component (conotoxin MVIIA) from Conus magus. "People suffering from untreatable chronic pain may soon find relief in a unique drug based on a chemical found in snail venom. Scientists say the new pain killer - soon to be reviewed by the FDA - is a thousand times more potent than morphine". Ten years ago biochemists isolated a chemical from Cone snail venom that may soon relieve chronic pain for millions of people. Called Ziconitide, the drug is a thousand times more potent than morphine -- without any of morphine's troubling side effects. [ACS] (Video not online)
6 July 1999
Rick Negus has provided five plates of antique shells featuring prints of various Conus species.
Conus 1, (Plate 19); Conus 2 (Plate 27); Conus 3 (Plate 29);
Conus 4 (Plate 3); and Conus 5.
22 June 1999
Added Russell Kelley to list of folk interested in Conidae. Russell Kelley is a natural history film maker in Australia with a background in palaeontology and tropical marine invertebrate ecology/evolution. During 2000 he will be building a 3D mesh model of a conesnail and its internals in order to animate the mechanics of envenomation. He welcomes interest in this area and invites you to contact him.
14 June 1999
The first issue of Current Opinion in CPNS Investigational Drugs is available FREE on the web [requires Adobe Reader] and contains a 14 page review article on omega conotoxin MVIIA (aka SNX-111, Ziconotide) from Conus magus, by Christine Heading entitled: "Ziconotide, Neurex Corp". Current Opinion in CPNS Investigational Drugs (1999) 1(1): 153-166.
13 June 1999
In 1969, S. Peter Dance published his book "Rare Shells" in which he illustrated and discussed fifty shells which had an interesting and often exciting history. Jacksonville Shell Club member Harry G. Lee has now assembled these into a web page which includes the following "rare" cones (#39-#46) Conus thomae Gmelin, 1791 - St. Thomas Cone;
Conus cervus Lamarck, 1822
;
Conus crocatus Lamarck, 1810;
Conus gloriamaris Chemnitz, 1777 - Glory-of-the-seas Cone;
Conus milneedwardsi Jousseaume, 1894 - Gloria-of-India Cone;
Conus excelsus Sowerby, 1908 - Illustrious Cone; Conus adamsonii Broderip, 1836; and
Conus dusaveli (H. Adams, 1872) - Du Savel's Cone
12 June 1999
For a fascinating account of the rapid evolution of cone shell toxin genes (with a commentary by Jon-Paul Bingham) see the featured News in Science segment from the ABC "The Lab" Science News Stories for 9 June 1999, entitled " Deadly sea snails have fast changing genes (see also Reuters; and ABCNEWS "Snails not slow at evolution"). The original article by Thomas F. Duda Jr.* and Stephen R. Palumbi from the Department of Organismic and Evolutionary Biology, Biological Laboratories, Harvard University appeared in Proc. Natl. Acad. Sci. (USA) 96, (12), 6820-6823 and is entitled "Molecular genetics of ecological diversification: Duplication and rapid evolution of toxin genes of the venomous gastropod Conus". [ Abstract: "Predatory snails in the marine gastropod genus Conus stun prey by injecting a complex mixture of peptide neurotoxins. These conotoxins are associated with trophic diversification and block a diverse array of ion channels and neuronal receptors in prey species, but the evolutionary genesis of this functional diversity is unknown. Here we show that conotoxins with little amino acid similarity are in fact products of recently diverged loci that are rapidly evolving by strong positive selection in the vermivorous cone, Conus abbreviatus, and that the rate of conotoxin evolution is higher than that of most other known proteins. Gene duplication and diversifying selection result in the formation of functionally variable conotoxins that are linked to ecological diversification and evolutionary success of this genus"]. Also contains data about Conus lividus.BGL.
4 June 1999
An interesting account of the strategy used by three fish-hunting cones (C. ermineus, C. consor and C. catus) to capture their prey will be published in the July issue of Toxicon. Click on the journal name to read the abstract.
Le Gall, F., Favreau, P., Richard, G., Letourneux, Y., Molgo, J.(1999) "The strategy used by some piscivorous cone snails to capture their prey: the effects of their venoms on vertebrates and on isolated neuromuscular preparations". Toxicon 37: 985-998.
31 May 1999
Chris Parks from Image Quest 3-D has a colorful and informative "News" page reporting on an article from the Sunday Times, UK, 23rd May 1999, by Bruce Kemble, entitled "Poisons from snail kills human pain", that brings together some recent information on the use of Ziconotide (SNX-111, the omega conotoxin from Conus magus) for the prevention of pain. In addition, the site contains images of live Conus marmoreus and "Conus omaria" (but in fact Conus textile) including a high power shot of the harpoon of an Omaria cone.
28 May 1999
Surprise ! Nathaniel Heintz and Julie Miwa reported in the May 28, 1999, issue of Neuron, that the brain of a mouse harbors a molecule (termed 'lynx1') similar to a major component of the deadly toxin, alpha-bungarotoxin. [alpha-bungarotoxin is a member of a large family of proteins called Ly-6. With that in mind, Heintz and Miwa named their gene "lynx," for Ly-6 neurotoxin].
Additional collaborators in Lorna Role's laboratory at Columbia University tested lynx1's effect on nicotinic acetylcholine receptors expressed in frog oocytes. Miwa said the acetylcholine response in the eggs was 30 percent larger after bathing them with lynx1, suggesting that lynx1 might enhance the action of acetylcholine.
26 May 1999
Added two new references on omega Conotoxin GVIA structure from Conus geographus.
Flinn JP, Pallaghy PK, Lew, M.J., Murphy, R., Angus, J.A., Norton, R.S. (1999) "Roles of key functional groups in omega-conotoxin GVIA Synthesis, structure and functional assay of selected peptide analogues". Eur J Biochem 262: 447-455). [The contributions of various functional groups to the pharmacophore of the N-type calcium-channel blocker, GVIA, were investigated using structural and in-vitro functional studies of analogues substituted at one or two positions with non-native residues. Three functional assays (sympathetic nerve stimulation of rat isolated vas deferens, right atrium and mesenteric artery) were employed to monitor N-type calcium-channel activity. The data provide a detailed picture of which residues are important for activity [see also alanine scan Lew et al. (1997) J. Biol. Chem. 272, 12014-12023]. A disubstituted chimera of GVIA and omega-conotoxin MVIIA was more potent than either native molecule. The more detailed description of the GVIA pharmacophore obtained here provides a better basis for the future design of truncated peptide and peptidomimetic analogues].
Pallaghy, P.K. and Norton, R.S. (1999) "Refined solution structure of omega-conotoxin GVIA: implications for calcium channel binding". J Pept Res 53: 343-51 [Describes a high-resolution solution structure of this member of the 'inhibitor cystine knot' protein family. The NMR data provide an improved basis for docking GVIA with models of the calcium channel. Two qualitatively different backbone conformations in the segment from Thr11 to Asn14 persisted in the restrained simulated annealing calculations. It is possible that GVIA is genuinely flexible at this segment, spending a finite time in the alternative conformation, and this may influence its interaction with the calcium channel].
22 May 1999
Cone shells are predatory marine snails that hunt at night - but who has seen them in action ? Don Barclay from Pago Pago placed some live cone snails in a marine tank and observed their behavior to each other and to other marine molluscs over a period of several weeks. He described their antics in a series of postings to the CONCH-L Mailing List. Carole Marshall informed members of the CONCH-L Mailing List that The Palm Beach County Shell Club webmasters enjoyed the series so much that they put it on their web site. The series, called Cone Wars (1-9) can be accessed at http://www.gopbi.com/community/groups/PBCshell or directly from the links below :
The Palm Beach County Shell Club was formed in 1958 to foster the education of its members about shells and the animals that make them. They have monthly meetings to learn about living shells, fossil shells, the identification of shells and other underwater educational pursuits.
Lynn Scheu from COA has let us know that Don Barclay's Cone Wars will be published in its entirety, illustrated, in the September (and maybe December 1999) issue(s) of American Conchologist, for all those of you who missed an installment here and there, as well as those unfortunate folks who are not on Conch-L. Many American Conchologist articles are put up on the Conch-Net Website after publication.
.
19 May 1999
Added something new from the ol' geographus venom. Contulakin-G is a 16 amino acid O-linked glycopeptide (pGlu-Ser-Glu-Glu-Gly-Gly-Ser-Asn-Ala-Thr-Lys-Lys-Pro-Tyr-Ile-Leu-OH, pGlu is pyroglutamate) from Conus geographus, whose C-terminus resembles neurotensin. Causes motor control-associated dysfunction when injected into mice. The investigators conclude "that O-linked glycosylation appears to be a highly unusual strategy for increasing the efficacy of toxins directed against neurotransmitter receptors". Craig, A. G., Norberg, T., Griffin, D., Hoeger, C., Akhtar, M., Schmidt, K., Low, W., Dykert, J., Richelson, E., Navarro, V., Mazella, J., Watkins, M., Hillyard, D., Imperial, J., Cruz, L. J., Olivera, B. M. (1999). "Contulakin-G, an O-Glycosylated Invertebrate Neurotensin" J. Biol. Chem. 274: 13752-13759 (1999).
[Reminiscent of enhancing effects of glycosylation of surugatoxin to give neosurugatoxin a marine toxin from the Japanese ivory mollusc (Babylonia japonica)
that potently inbibits the nicotinic response in several tissues.]
15 May 1999
Added
report of two novel alpha-conotoxins, alpha-CnIA (major) and alpha-CnIB
(minor), of 14 and 12 amino acids, respectively, purified by HPLC from
the venom of the fish-hunting cone snail Conus consors.
Conotoxin
Sequence
CnIA
GRCCHPACGKYYSC* CnIB
CCHPACGKYYSC*
MI
GRCCHPACGKNYSC*
alpha-CnIA and alpha-CnIB are very similar
in structure to alpha-conotoxin-MI (from C. magus). alpha-CnIA has
a Tyr (Y) in position 11, instead of the Asn (N) in alpha-MI. alpha-CnIA
and CnIB possess the three/five loop structure of conotoxins GI, GIA, GII,
MI, SI, SIA, and SII (alpha3/5 subclass).
These peptides were characterized by binding
experiments with Torpedo nicotinic acetylcholine receptor (nAChR)
and by NMR. alpha-CnIA appears to be a potent and selective blocker
of muscle-type nAChRs as evidenced by electrophysiological recordings with
amphibian and mammalian isolated neuromuscular preparations.
Reference: Favreau, P., Krimm, I., Le Gall, F., Bobenrieth,
M.J., Lamthanh, H., Bouet, F., Servent, D., Molgo, J., Menez, A., Letourneux,
Y. and Lancelin, J-M. (1999) "Biochemical Characterization and Nuclear
Magnetic Resonance Structure of Novel alpha-Conotoxins Isolated from the
Venom of Conus consors". Biochemistry38: 6317-6326.
Reference reporting the identification, characterization,
and structure of a gamma-carboxyglutamic acid-containing peptide, conotoxin
e-TxIX, from Conus textile. This conotoxin has four cysteine
residues, and an unparalleled degree of posttranslational processing including
bromination, hydroxylation, and glycosylation. This conotoxin selectively
reduces neurotransmitter release at Aplysia cholinergic synapses
by reducing the presynaptic influx of Ca2+ in a slow and reversible fashion.
Alan C. Rigby, Estelle Lucas-Meunier,
Dário E. Kalume, Eva Czerwiec, Björn Hambe, Ingrid Dahlqvist,
Philippe Fossier, Gérard Baux, Peter Roepstorff, James D. Baleja,
Barbara C. Furie, Bruce Furie, and Johan Stenflo (1999) "A conotoxin from
Conus textile with unusual posttranslational modifications reduces
presynaptic Ca2+ influx". PNAS 96: 5758-5763 (1999).
7 May 1999
A colourful montage of 32 cone shells is presented
on this page maintained by Vincent Crayssac from Caledonian Seashells. Vincent also
maintains a list of links to other shell dealers, shell clubs and societies, individual homepages and publications.
Looking for images of raduae ? - the venomous harpoons that cone shells use to deliver their deadly venom into prey.
Here are some images of radulae available on the web. Image 1 Image 2 Image 3
These come from a talk given by Prof Baldomero Olivera at a symposium "The Value of Plants, Animals and Microbes to Human Health", held on April 17 and 18, 1998, at the American Museum of Natural History.
Additional scientific articles on conotoxins.
Reference concerning the selectivity of conotoxin ImI from Conus imperialis for the neuronal-type nicotinic receptor. Broxton, N.M., Down, J.G., Gehrmann, J., Alewood, P.F., Satchell, D.G. and Livett, B.G.
"Alpha-conotoxin ImI inhibits the alpha-bungarotoxin-resistant nicotinic response in bovine adrenal chromaffin cells".
J. Neurochem. 72:1656-1662 (1999).
Reference concerning the formation of
disulfide bonds in conotoxin GI from Conus geographus. Kaerner, A.
and Rahenstein, D.L. "Stability and structure-forming properties of the two disufide bonds of alpha-contoxin GI"
Biochemistry 38 5459-5470 (1999).
Reference concerning the NMR solution structure of
alpha conotoxin ImI from Conus imperialis. Rogers, J.P., Luginbuhl, P., Shen, G.S., McCabe, R.T., Stevens, R.C. and Wemmer, D.E. "NMR solution structure of alpha-conotoxin ImI and comparison to other conotoxins specific for neuronal nicotinic acetylcholine receptors."
Biochemistry 38 3874-3882 (1999).
Reference concerning the presence of a single sulfated tyrosine residue within both alpha conotoxin PnIA and PnIB isolated from the venom of Conus pennaceus a molluscivorous cone shell from the Red Sea. Wolfender, J.L., Chu, F., Ball, H., Wolfender, F., Fainzilber, M., Baldwin, M.A. and Burlingame, A.L.
(1999) "Identification of tyrosine sulfation in Conus pennaceus conotoxins alpha-PnIA and alpha-PnIB:
further investigation of labile sulfo- and phosphopeptides by electrospray, matrix-assisted laser
desorption/ionization (MALDI) and atmospheric pressure MALDI mass spectrometry. J Mass Spectrom. 34: 447-54 (1999).
30 April 1999
For an introduction to cone shells you wont find a
prettier site than this one at Seashells-Are-Us by David Schroeder (hosted by Concentric, but previously hosted by CalPoly
San Luis Obispo). The site includes images
of Conus ammiralis, Conus bengalensis, Conus dominicanus, Conus
muriculatus floridulus, Conus marmoreus, Conus tulipa, Conus excelsus, and
three photos of a Conus textile attacking a Nassarius.
The web address is
http://www.concentric.net/~Cschroed/html/cones.html According to David Schroeder, "in years past, Cone Shells were
commonly known as cigarette shells. They got this name because the person
who got accidentally stung by a cone shell would have about enough time to
smoke a cigarette, before paralysis and death would set in".
This page is worth a visit for the beautiful specimens of Conus
selected.
Added reference (to an old but fascinating piece of Scientific Correspondence) from Fainzilber, M.,
Napchi, I., Gordon, D. and Zlotkin, E. (1994) "Marine warning via peptide toxin".
Nature (Lond.) 369: 192-193.[ Studied C. striatus, C. textile, C. pennaceus, C. nussatella,
C. arenatus, C. tesselatus, C. generalis, C. flavidus, C. rattus, C. parvatus, C. ventricosus,
and Strombus. The results suggest the existence of phylogenetically specific alarm cues
in Conidae. Only the molluscivorous species venoms were active against Strombus.
This is the first documented case of a defined peptide acting as an interspecific alarm cue in marine ecosystems.]
31 March 1999
This site includes nice graphics of interaction of a
mu-conotoxin with the sodium channel. Dudley, S. Jr., Todt, H. Lipkind, G.
and Fozzard, H.A. (1995)"A mu-conotoxin insensitive Na+ channel mutant:
Possible localization of a binding site at the outer vestibule".
Biophysical Journal 69 1657-1665.
Added additional reference concerning the NMR solution structure of
alpha-conotoxin MII from Conus magus. Justine M Hill, Clasien J Oomen,
Les P Miranda, Jon-Paul Bingham, Paul F Alewood and David J Craik (1998)
"Three-Dimensional Solution Structure of a-Conotoxin MII by NMR Spectroscopy:
Effects of Solution Environment on Helicity". Biochemistry 37 15621-15630.
14 March 1999
Added K. Venkateshvaran to list of folk interested in Conidae. K. Venkateshvaran is a marine biologist from India working on biotoxins from marine animals and whose current interest is in bioactive peptides from Conus sp. occurring in Indian waters.
Added additional reference concerning the alpha-A conotoxin family from Conus ermenius, to the list of references from Olivera's laboratory ."Differential targeting of nicotinic acetylcholine receptors by novel alphaA-conotoxins".
Jacobsen, R., Yoshikami, D., Ellison, M., Martinez, J., Gray, W.R., Cartier, G.E., Shon, K.J., Groebe, D.R.,
Abramson, S.N., Olivera, B.M. and McIntosh, J.M. (1997)
J Biol Chem 272 (36) 22531-22537.
Elsevier have released their "Comprehensive Toxicology" on CD-ROM.
Previously available only as a 13 Volume print edition, this new CD-ROM
facilitates fast searching for specific information.
Enhanced by 50,000 reference abstracts from the Elsevier's database,
EMBASE, this CD-ROM provides access to the wider primary literature.
The search engine allows one to do natural language searching, concept
searching, searching through related terms as well as queries by example.
The CD-ROM requires no experience or training and is ideal for scientists
and students in academic, industrial or government settings. For more
information and a FREE on line demonstration visit the website
at http//www.elsevier.nl/locate/comptox
14 January 1999
Conus striatus - added reference to a paper that describes the characterization of a novel
peptide, kappa A-conotoxin SIVA, from the venom of the fish-hunting cone snail Conus
striatus. The peptide inbibits voltage-gated K+ channels, bringing about spastic paralytic
symptoms when injected into fish, and repetitive action potentials in frog nerve-muscle
preparations. This conotoxin has 3 disulfide bonds and 30 amino acids. A novel biochemical
feature is the unusually long linear N-terminal tail (11 residues) which contains one
O-glycosylated serine at position 7. This is the first evidence for O-glycosylation as a
post-translational modification in a biologically active Conus peptide.
Conus bairstowi -
here is an interesting article by Brian Hayes
from Algoa Bay Specimen Shells,
Port Elizabeth, South Africa. It appeared first in the World Shells magazine
(September, 1996), a glossy magazine filled with colour photos and up-to-date articles on many of the latest
findings.
Notice of meeting -
Joint meeting of the Malacological Society of London and the Linnean Society of London, in the rooms of the Linnean Society,
Burlington House, Piccadilly, London, at 5 pm, Thursday 21 January, 1999 PREDATORY MOLLUSCS Speakers include - John Taylor"Evolution of the hypodermic feeding system of Conus"
Cone shell smorgasboard: Here are listed the more than 650 species of CONIDAE Cone shell images from Guido T. Poppe (~ 150 cone shells are illustrated).
26 December 1998
Molecular graphics images of conotoxins in pdb format have been updated to include 22 structures. An additional 7 structures are undergoing processing or "on hold". Three of these will be released upon publication and another three are "on-hold" until 18 January 1999. See also 3-D Images of Conotoxins
28 October 1998
Cone
Shell and Conotoxins Homepage officially launched by Dynamix during the Multimedia
Conference '98 in Plaza Conference Centre, Melbourne University.
25 October 1998
Point your browser at the link below for and excellent summary of
several talks given at a symposium on the value of plants, animals and microbes to human
health held at the Museum of Natural History in New York, NY, June 1998.
Poisonous Frogs Fight Pain - John W. Daly
Complex Cone Snail Venom - Baldomero Olivera / George Miljanich
John Down and Bruce Livett presented a talk entitled "Cone
shell toxins: molecular prospecting for novel drugs from the sea" at the Kaleide
Theatre (RMIT), 360 Swanston St., (opposite A'Beckett St.), Melbourne (Australia) on
Tuesday 27 October at 8.00 pm for the Victorian Division of ANZAAS. Published in Newsletter No. 3, November 1998, pp. 3-4 (1998)
At this symposium, scientists, environmentalists and policymakers
from around the world discussed the link between conserving biodiversity and sustaining
human health and well-being. This website features biographies and abstracts from each of
the presenters, along with their speech, presented through RealAudio.
View
Cone Shells and Conotoxins Discussion List Archive 
Cone
Shell and Conotoxins Homepage officially launched by 
