| Conantokin-P, an unusual conantokin with a long disulfide loop. | |
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MedLine Citation:
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PMID: 18586049 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The conantokins are a family of Conus venom peptides (17-27AA) that are N-methyl-d-aspartate (NMDA) receptor antagonists. Conantokins lack disulfide bridges (six out of seven previously characterized peptides are linear), but contain multiple residues of gamma-carboxyglutamate. These post-translationally modified amino acids confer the largely helical structure of conantokins by coordinating divalent metal ions. Here, we report that a group of fish-hunting cone snails, Conus purpurascens and Conus ermineus, express a distinctive branch of the conantokin family in their venom ducts. Two novel conantokins, conantokin-P (Con-P) and conantokin-E (Con-E) are 24AA long and contain five gamma-carboxyglutamate residues. These two peptides are characterized by a long disulfide loop (12 amino acids including two Gla residues between the Cys residues). The oxidative folding studies of Con-P revealed that the formation of the disulfide bond proceeded significantly faster in the presence of Ca(++) ions. Circular dichroism suggested that Con-P is less helical than other previously characterized conantokins. Con-P blocks NMDA receptors containing NR2B subunit with submicromolar potency. Furthermore, the subtype-selectivity for different NR2 subunits differs from that of the previously characterized conantokins. Our results suggest that different branches of the phylogenetic tree of cone snails have evolved distinct groups of conantokins, each with its own unique biochemical features. |
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Authors:
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Konkallu Hanumae Gowd; Vernon Twede; Maren Watkins; K S Krishnan; Russell W Teichert; Grzegorz Bulaj; Baldomero M Olivera |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2008-06-03 |
Journal Detail:
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Title: Toxicon : official journal of the International Society on Toxinology Volume: 52 ISSN: 0041-0101 ISO Abbreviation: Toxicon Publication Date: 2008 Aug |
Date Detail:
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Created Date: 2008-08-25 Completed Date: 2008-10-28 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 1307333 Medline TA: Toxicon Country: England |
Other Details:
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Languages: eng Pagination: 203-13 Citation Subset: IM |
Affiliation:
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Department of Biology, University of Utah, Salt Lake City, UT 84112, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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1-Carboxyglutamic Acid
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chemistry Amino Acid Sequence Animals Circular Dichroism Conotoxins / chemical synthesis, chemistry Conus Snail / physiology* DNA / analysis Disulfides / chemistry* Helix-Loop-Helix Motifs Molecular Sequence Data Mollusk Venoms / chemistry* Phylogeny Receptors, N-Methyl-D-Aspartate / chemistry |
| Grant Support | |
ID/Acronym/Agency:
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GM48677/GM/NIGMS NIH HHS; R21 NS055845-01/NS/NINDS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Conotoxins; 0/Disulfides; 0/Mollusk Venoms; 0/NR2B NMDA receptor; 0/Receptors, N-Methyl-D-Aspartate; 0/conantokin-E; 0/conantokin-P; 53445-96-8/1-Carboxyglutamic Acid; 9007-49-2/DNA |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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