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32  structures 9  species 0  interactions 11  sequences 1  architecture

Family: Conotoxin (PF02950)

Summary: Conotoxin

Pfam includes annotations and additional family information from a range of different sources. These sources can be accessed via the tabs below.

This is the Wikipedia entry entitled "Conotoxin". More...

Conotoxin Edit Wikipedia article

Alpha conotoxin precursor
Alpha-Conotoxin from Conus pennaceus 1AKG.png
α-Conotoxin PnIB from C. pennaceus, disulfide bonds shown in yellow. From the University of Michigan's Orientations of Proteins in Membranes database, PDB: 1AKG​.
Identifiers
Symbol Toxin_8
Pfam PF07365
InterPro IPR009958
PROSITE PDOC60004
SCOP 1mii
SUPERFAMILY 1mii
OPM superfamily 157
OPM protein 1akg
Omega conotoxin
Ziconotide 1DW5.png
Schematic diagram of the three-dimensional structure of ω-conotoxin MVIIA (ziconotide). Disulfide bonds are shown in gold. From PDB: 1DW5​.
Identifiers
Symbol Conotoxin
Pfam PF02950
InterPro IPR004214
SCOP 2cco
SUPERFAMILY 2cco
OPM superfamily 120
OPM protein 1fyg

A conotoxin is one of a group of neurotoxic peptides isolated from the venom of the marine cone snail, genus Conus.

Conotoxins, which are peptides consisting of 10 to 30 amino acid residues, typically have one or more disulfide bonds. Conotoxins have a variety of mechanisms of actions, most of which have not been determined. However, it appears that many of these peptides modulate the activity of ion channels.[1] Over the last few decades conotoxins have been the subject of pharmacological interest.[2]

The LD50 of conotoxin is 50 ng/kg.[3][not in citation given]

Hypervariability

Conotoxins are hypervariable even within the same species; the genes that encode them do not act endogenously,[4] and thus are less conserved and more likely to experience gene duplication events and nonsynonymous mutations which lead to the development of novel functions.[5] These genes will experience less selection against mutations, and therefore mutations will remain in the genome longer, allowing more time for potentially beneficial novel functions to arise.[6] Variability in conotoxin components reduces the likelihood that prey organisms will develop resistance; thus cone snails are under constant selective pressure to maintain polymorphism in these genes because failing to evolve and adapt will lead to extinction (Red Queen hypothesis).[7]

Disulfide connectivities

Types of conotoxins also differ in the number and pattern of disulfide bonds.[8] The disulfide bonding network, as well as specific amino acids in inter-cysteine loops, provide the specificity of conotoxins.[9]

Types and biological activities

The number of conotoxins whose activities have been determined so far is five, and they are called the α(alpha)-, δ(delta)-, κ(kappa)-, μ(mu)-, and ω(omega)- types. Each of the five types of conotoxins attacks a different target:

Alpha

Alpha conotoxins have two types of cysteine arrangements,[17] and are competitive nicotinic acetylcholine receptor antagonists.

Delta and kappa, and omega

Omega, delta and kappa families of conotoxins have a knottin or inhibitor cystine knot scaffold. The knottin scaffold is a very special disulfide-through-disulfide knot, in which the III-VI disulfide bond crosses the macrocycle formed by two other disulfide bonds (I-IV and II-V) and the interconnecting backbone segments, where I-VI indicates the six cysteine residues starting from the N-terminus. The cysteine arrangements are the same for omega, delta and kappa families, even though omega conotoxins are calcium channel blockers, whereas delta conotoxins delay the inactivation of sodium channels, and kappa conotoxins are potassium channel blockers.[8]

Mu

Mu-conotoxin
PDB 1r9i EBI.jpg
nmr solution structure of piiia toxin, nmr, 20 structures
Identifiers
Symbol Mu-conotoxin
Pfam PF05374
Pfam clan CL0083
InterPro IPR008036
SCOP 1gib
SUPERFAMILY 1gib
OPM superfamily 120
OPM protein 1ag7

Mu-conotoxins have two types of cysteine arrangements, but the knottin scaffold is not observed.[18] Mu-conotoxins target the muscle-specific voltage-gated sodium channels,[8] and are useful probes for investigating voltage-dependent sodium channels of excitable tissues.[18][19] Mu-conotoxins target the voltage-gated sodium channels, preferentially those of skeletal muscle,[20] and are useful probes for investigating voltage-dependent sodium channels of excitable tissues.[21]

Different subtypes of voltage-gated sodium channels are found in different tissues in mammals, e.g., in muscle and brain, and studies have been carried out to determine the sensitivity and specificity of the mu-conotoxins for the different isoforms.[22]

See also

References

  1. ^ Terlau H, Olivera BM (2004). "Conus venoms: a rich source of novel ion channel-targeted peptides". Physiol. Rev. 84 (1): 41–68. PMID 14715910. doi:10.1152/physrev.00020.2003. 
  2. ^ Olivera BM, Teichert RW (2007). "Diversity of the neurotoxic Conus peptides: a model for concerted pharmacological discovery.". Mol Interv. 7 (5): 251–60. PMID 17932414. doi:10.1124/mi.7.5.7. 
  3. ^ http://www.aristatek.com/Newsletter/MAY08/TechSpeak.pdf
  4. ^ Biggs JS, Watkins M, Puillandre N, Ownby JP, Lopez-Vera E, Christensen S, Moreno KJ, Bernaldez J, Licea-Navarro A, Corneli PS, Olivera BM (July 2010). "Evolution of Conus peptide toxins: analysis of Conus californicus Reeve, 1844". Mol. Phylogenet. Evol. 56 (1): 1–12. PMC 3488448 Freely accessible. PMID 20363338. doi:10.1016/j.ympev.2010.03.029. 
  5. ^ Olivera BM, Watkins M, Bandyopadhyay P, Imperial JS, de la Cotera EP, Aguilar MB, Vera EL, Concepcion GP, Lluisma A (September 2012). "Adaptive radiation of venomous marine snail lineages and the accelerated evolution of venom peptide genes". Ann. N. Y. Acad. Sci. 1267 (1): 61–70. PMC 3488454 Freely accessible. PMID 22954218. doi:10.1111/j.1749-6632.2012.06603.x. 
  6. ^ Wong ES, Belov K (March 2012). "Venom evolution through gene duplications". Gene. 496 (1): 1–7. PMID 22285376. doi:10.1016/j.gene.2012.01.009. 
  7. ^ Liow LH, Van Valen L, Stenseth NC (July 2011). "Red Queen: from populations to taxa and communities". Trends Ecol. Evol. (Amst.). 26 (7): 349–58. PMID 21511358. doi:10.1016/j.tree.2011.03.016. 
  8. ^ a b c Jones RM, McIntosh JM (2001). "Cone venom--from accidental stings to deliberate injection". Toxicon. 39 (10): 1447–1451. PMID 11478951. doi:10.1016/S0041-0101(01)00145-3. 
  9. ^ Sato K, Kini RM, Gopalakrishnakone P, Balaji RA, Ohtake A, Seow KT, Bay BH (2000). "lambda-conotoxins, a new family of conotoxins with unique disulfide pattern and protein folding. Isolation and characterization from the venom of Conus marmoreus". J. Biol. Chem. 275 (50): 39516–39522. PMID 10988292. doi:10.1074/jbc.M006354200. 
  10. ^ Nicke A, Wonnacott S, Lewis RJ (2004). "Alpha-conotoxins as tools for the elucidation of structure and function of neuronal nicotinic acetylcholine receptor subtypes". Eur. J. Biochem. 271 (12): 2305–2319. PMID 15182346. doi:10.1111/j.1432-1033.2004.04145.x. 
  11. ^ Leipold E, Hansel A, Olivera BM, Terlau H, Heinemann SH (2005). "Molecular interaction of delta-conotoxins with voltage-gated sodium channels". FEBS Lett. 579 (18): 3881–3884. PMID 15990094. doi:10.1016/j.febslet.2005.05.077. 
  12. ^ Shon KJ, Stocker M, Terlau H, Stühmer W, Jacobsen R, Walker C, Grilley M, Watkins M, Hillyard DR, Gray WR, Olivera BM (1998). "kappa-Conotoxin PVIIA is a peptide inhibiting the shaker K+ channel". J. Biol. Chem. 273 (1): 33–38. PMID 9417043. doi:10.1074/jbc.273.1.33. 
  13. ^ Li RA, Tomaselli GF (2004). "Using the deadly mu-conotoxins as probes of voltage-gated sodium channels". Toxicon. 44 (2): 117–122. PMC 2698010 Freely accessible. PMID 15246758. doi:10.1016/j.toxicon.2004.03.028. 
  14. ^ Nielsen KJ, Schroeder T, Lewis R (2000). "Structure-activity relationships of omega-conotoxins at N-type voltage-sensitive calcium channels" (abstract). J. Mol. Recognit. 13 (2): 55–70. PMID 10822250. doi:10.1002/(SICI)1099-1352(200003/04)13:2<55::AID-JMR488>3.0.CO;2-O. 
  15. ^ Bowersox SS, Luther R (1998). "Pharmacotherapeutic potential of omega-conotoxin MVIIA (SNX-111), an N-type neuronal calcium channel blocker found in the venom of Conus magus". Toxicon. 36 (11): 1651–1658. PMID 9792182. doi:10.1016/S0041-0101(98)00158-5. 
  16. ^ Prommer E (2006). "Ziconotide: a new option for refractory pain". Drugs Today. 42 (6): 369–78. PMID 16845440. doi:10.1358/dot.2006.42.6.973534. 
  17. ^ Gray WR, Olivera BM, Zafaralla GC, Ramilo CA, Yoshikami D, Nadasdi L, Hammerland LG, Kristipati R, Ramachandran J, Miljanich G (1992). "Novel alpha- and omega-conotoxins from Conus striatus venom". Biochemistry. 31 (41): 11864–11873. PMID 1390774. doi:10.1021/bi00162a027. 
  18. ^ a b Nielsen KJ, Watson M, Adams DJ, Hammarström AK, Gage PW, Hill JM, Craik DJ, Thomas L, Adams D, Alewood PF, Lewis RJ (July 2002). "Solution structure of mu-conotoxin PIIIA, a preferential inhibitor of persistent tetrodotoxin-sensitive sodium channels". J. Biol. Chem. 277 (30): 27247–55. PMID 12006587. doi:10.1074/jbc.M201611200. 
  19. ^ Zeikus RD, Gray WR, Cruz LJ, Olivera BM, Kerr L, Moczydlowski E, Yoshikami D (1985). "Conus geographus toxins that discriminate between neuronal and muscle sodium channels". J. Biol. Chem. 260 (16): 9280–8. PMID 2410412. 
  20. ^ McIntosh JM, Jones RM (October 2001). "Cone venom--from accidental stings to deliberate injection". Toxicon. 39 (10): 1447–51. PMID 11478951. doi:10.1016/S0041-0101(01)00145-3. 
  21. ^ Cruz LJ, Gray WR, Olivera BM, Zeikus RD, Kerr L, Yoshikami D, Moczydlowski E (August 1985). "Conus geographus toxins that discriminate between neuronal and muscle sodium channels". J. Biol. Chem. 260 (16): 9280–8. PMID 2410412. 
  22. ^ Floresca CZ (2003). "A comparison of the mu-conotoxins by [3H]saxitoxin binding assays in neuronal and skeletal muscle sodium channel.". Toxicol Appl Pharmacol. 190 (2): 95–101. PMID 12878039. doi:10.1016/s0041-008x(03)00153-4. 

External links

  • Conotoxins at the US National Library of Medicine Medical Subject Headings (MeSH)
  • Baldomero "Toto" Olivera's short talk. "Conus Peptides". 
  • Kaas Q, Westermann JC, Halai R, Wang CK, Craik DJ. "ConoServer". Institute of Molecular Bioscience, The University of Queensland, Australia. Retrieved 2009-06-02. A database for conopeptide sequences and structures 

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This is the Wikipedia entry entitled "Contryphan". More...

Contryphan Edit Wikipedia article

Contryphan
1NXN.png
NMR structure of Contryphan-Vn. The peptide backbone is depicted by a curved tube while the amino acid side-chains are represented by capped sticks. Carbon atoms are colored grey, nitrogen atoms blue, oxygen atoms red, and sulfur atoms yellow.[1]
.
Identifiers
Symbol Contryphan_CS
Pfam PF02950
InterPro IPR011062
PROSITE PS60027
SCOP 2cco
SUPERFAMILY 2cco

The contryphans (conus + tryptophan) are a family of peptides that are active constituents of the potent venom produced by cone snail (genus conus). The two amino acid cysteine residues in contryphans are linked by a disulfide bond. In addition, contryphans undergo an unusual degree of post-translational modification including epimerization of leucine and tryptophan, tryptophan bromination, amidation of the C-terminus, and proline hydroxylation.[2]

Family members

Conus textile, which produces contryphans

Contryphan family members include:

Peptide Sequence Species Reference
Des(Gly1)contryphan-R COwEPWC-NH2 C. radiatus [3]
Contryphan-R GCOwEPWC-NH2 Conus radiatus [3]
Bromocontyphan-R GCOwEPXC-NH2 C. radiatus [4]
Contryphan-Sm GCOwQPWC-NH2 Conus stercusmuscarum [5]
Contryphan-P GCOwDPWC-NH2 C. purpurascens [5]
Contryphan-R/Tx GCOwEPWC-NH2 Conus textile [5]
Contryphan-Tx GCOWQPYC-NH2 Conus textile [5]
Contryphan-Vn GDCPwKPWC-NH2 Conus ventricosus [6]
Leu-contryphan-P GCVlLPWC-OH Conus purpurascens [7]
Leu-contryphan-Tx CVlYPWC-NH2 Conus textile [5]
Glaconryphan-M NγSγCPWHPWC-NH2 Conus marmoreus [2]

where the sequence abbreviations stand for:

and the remainder of the letters refer to the standard one letter abbreviations for amino acids.

Mechanism of toxicity

The venom of cone snails cause paralysis of their fish prey. The molecular target has not been determined for all contryphan peptides, however it is known that contryphan-Vn is a Ca2+-dependent K+ channel modulator,[6] while glacontryphan-M is a L-type calcium channel blocker.[2]

See also

References

  1. ^ PDB: 1NXN​; Eliseo T, Cicero DO, Romeo C, Schininà ME, Massilia GR, Polticelli F, Ascenzi P, Paci M (June 2004). "Solution structure of the cyclic peptide contryphan-Vn, a Ca2+-dependent K+ channel modulator". Biopolymers. 74 (3): 189–98. doi:10.1002/bip.20025. PMID 15150794. 
  2. ^ a b c Hansson K, Ma X, Eliasson L, Czerwiec E, Furie B, Furie BC, Rorsman P, Stenflo J (2004). "The first gamma-carboxyglutamic acid-containing contryphan. A selective L-type calcium ion channel blocker isolated from the venom of Conus marmoreus". J. Biol. Chem. 279 (31): 32453–63. doi:10.1074/jbc.M313825200. PMID 15155730. 
  3. ^ a b Jimenéz EC, Olivera BM, Gray WR, Cruz LJ (1996). "Contryphan is a D-tryptophan-containing Conus peptide". J. Biol. Chem. 271 (45): 28002–5. doi:10.1074/jbc.271.45.28002. PMID 8910408. 
  4. ^ Jimenez EC, Craig AG, Watkins M, Hillyard DR, Gray WR, Gulyas J, Rivier JE, Cruz LJ, Olivera BM (1997). "Bromocontryphan: post-translational bromination of tryptophan". Biochemistry. 36 (5): 989–94. doi:10.1021/bi962840p. PMID 9033387. 
  5. ^ a b c d e Jacobsen R, Jimenez EC, Grilley M, Watkins M, Hillyard D, Cruz LJ, Olivera BM (1998). "The contryphans, a D-tryptophan-containing family of Conus peptides: interconversion between conformers". J. Pept. Res. 51 (3): 173–9. doi:10.1111/j.1399-3011.1998.tb01213.x. PMID 9531419. 
  6. ^ a b Massilia GR, Schininà ME, Ascenzi P, Polticelli F (2001). "Contryphan-Vn: a novel peptide from the venom of the Mediterranean snail Conus ventricosus". Biochem. Biophys. Res. Commun. 288 (4): 908–13. doi:10.1006/bbrc.2001.5833. PMID 11688995. 
  7. ^ Jacobsen RB, Jimenez EC, De la Cruz RG, Gray WR, Cruz LJ, Olivera BM (1999). "A novel D-leucine-containing Conus peptide: diverse conformational dynamics in the contryphan family". J. Pept. Res. 54 (2): 93–9. doi:10.1034/j.1399-3011.1999.00093.x. PMID 10461743. 

External links

This page is based on a Wikipedia article. The text is available under the Creative Commons Attribution/Share-Alike License.

This tab holds the annotation information that is stored in the Pfam database. As we move to using Wikipedia as our main source of annotation, the contents of this tab will be gradually replaced by the Wikipedia tab.

Conotoxin Provide feedback

Conotoxins are small snail toxins that block ion channels.

Literature references

  1. Gray WR, Olivera BM, Cruz LJ; , Annu Rev Biochem 1988;57:665-700.: Peptide toxins from venomous Conus snails. PUBMED:3052286 EPMC:3052286

  2. Pallaghy PK, Duggan BM, Pennington MW, Norton RS; , J Mol Biol 1993;234:405-420.: Three-dimensional structure in solution of the calcium channel blocker omega-conotoxin PUBMED:8230223 EPMC:8230223

Internal database links

Similarity to PfamA using HHSearch: Chi-conotoxin

External database links

SCOP: 2cco

This tab holds annotation information from the InterPro database.

InterPro entry IPR004214

Cone snail toxins, conotoxins, are small neurotoxic peptides with disulphide connectivity that target ion-channels or G-protein coupled receptors. Based on the number and pattern of disulphide bonds and biological activities, conotoxins can be classified into several families [PUBMED:11478951]. Omega, delta and kappa families of conotoxins have a knottin or inhibitor cysteine knot scaffold. The knottin scaffold is a very special disulphide-through-disulphide knot, in which the III-VI disulphide bond crosses the macrocycle formed by two other disulphide bonds (I-IV and II-V) and the interconnecting backbone segments, where I-VI indicates the six cysteine residues starting from the N terminus.

The disulphide bonding network, as well as specific amino acids in inter-cysteine loops, provide the specificity of conotoxins [PUBMED:10988292]. The cysteine arrangements are the same for omega, delta and kappa families, even though omega conotoxins are calcium channel blockers, whereas delta conotoxins delay the inactivation of sodium channels, and kappa conotoxins are potassium channel blockers [PUBMED:11478951]. Mu conotoxins have two types of cysteine arrangements, but the knottin scaffold is not observed. Mu conotoxins target the voltage-gated sodium channels [PUBMED:11478951], and are useful probes for investigating voltage-dependent sodium channels of excitable tissues [PUBMED:2410412]. Alpha conotoxins have two types of cysteine arrangements [PUBMED:1390774], and are competitive nicotinic acetylcholine receptor antagonists.

Gene Ontology

The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.

Cellular component extracellular region (GO:0005576)
Molecular function ion channel inhibitor activity (GO:0008200)
Biological process pathogenesis (GO:0009405)

Domain organisation

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Pfam Clan

This family is a member of clan Omega_toxin (CL0083), which has the following description:

This clan contains a set of related small protein toxins and what appears to be the functionally distinct Albumin I domain. All members of this clan have a knottin-like fold. Additional information about this clan may be found from [1].

The clan contains the following 34 members:

ACI44 Agouti Albumin_I Albumin_I_a Antifungal_pept Antimicrobial25 Argos Atracotoxin CART CBM_1 Chi-conotoxin Conotoxin LEAP-2 Mu-conotoxin Omega-toxin Tachystatin_A Tachystatin_B Toxin_11 Toxin_12 Toxin_16 Toxin_18 Toxin_20 Toxin_21 Toxin_22 Toxin_23 Toxin_24 Toxin_27 Toxin_28 Toxin_30 Toxin_35 Toxin_7 Toxin_9 UPF0506 Viral_cys_rich

Alignments

We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database (reference proteomes) using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the UniProtKB sequence database, the NCBI sequence database, and our metagenomics sequence database. More...

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(98)		 Full
(11)		 Representative proteomes UniProt
(1951)		 NCBI
(1833)		 Meta
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(5)		 RP35
(7)		 RP55
(11)		 RP75
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  Seed
(98)		 Full
(11)		 Representative proteomes UniProt
(1951)		 NCBI
(1833)		 Meta
(0)
RP15
(5)		 RP35
(7)		 RP55
(11)		 RP75
(14)
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  Seed
(98)		 Full
(11)		 Representative proteomes UniProt
(1951)		 NCBI
(1833)		 Meta
(0)
RP15
(5)		 RP35
(7)		 RP55
(11)		 RP75
(14)
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Trees

This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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Curation and family details

This section shows the detailed information about the Pfam family. You can see the definitions of many of the terms in this section in the glossary and a fuller explanation of the scoring system that we use in the scores section of the help pages.

Curation View help on the curation process

Seed source: Pfam-B_529 (release 6.4)
Previous IDs: none
Type: Domain
Author: Bateman A
Number in seed: 98
Number in full: 11
Average length of the domain: 78.30 aa
Average identity of full alignment: 33 %
Average coverage of the sequence by the domain: 91.01 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 26740544 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 25.1 25.1
Trusted cut-off 25.8 25.6
Noise cut-off 24.6 24.3
Model length: 75
Family (HMM) version: 16
Download: download the raw HMM for this family

Species distribution

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Structures

For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the Conotoxin domain has been found. There are 32 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.

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