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| | {{STRUCTURE_1ag7| PDB=1ag7 | SCENE= }} | | {{STRUCTURE_1ag7| PDB=1ag7 | SCENE= }} |
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| - | '''CONOTOXIN GS, NMR, 20 STRUCTURES'''
| + | ===CONOTOXIN GS, NMR, 20 STRUCTURES=== |
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| - | ==Overview==
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| - | BACKGROUND: The venoms of Conus snails contain small, disulfide-rich inhibitors of voltage-dependent sodium channels. Conotoxin GS is a 34-residue polypeptide isolated from Conus geographus that interacts with the extracellular entrance of skeletal muscle sodium channels to prevent sodium ion conduction. Although conotoxin GS binds competitively with mu conotoxin GIIIA to the sodium channel surface, the two toxin types have little sequence identity with one another, and conotoxin GS has a four-loop structural framework rather than the characteristic three-loop mu-conotoxin framework. The structural study of conotoxin GS will form the basis for establishing a structure-activity relationship and understanding its interaction with the pore region of sodium channels. RESULTS: The three-dimensional structure of conotoxin GS was determined using two-dimensional NMR spectroscopy. The protein exhibits a compact fold incorporating a beta hairpin and several turns. An unusual feature of conotoxin GS is the exceptionally high proportion (100%) of cis-imide bond geometry for the three proline or hydroxyproline residues. The structure of conotoxin GS bears little resemblance to the three-loop mu conotoxins, consistent with the low sequence identity between the two toxin types and their different structural framework. However, the tertiary structure and cystine-knot motif formed by the three disulfide bonds is similar to that present in several other polypeptide ion channel inhibitors. CONCLUSIONS: This is the first three-dimensional structure of a 'four-loop' sodium channel inhibitor, and it represents a valuable new structural probe for the pore region of voltage-dependent sodium channels. The distribution of amino acid sidechains in the structure creates several polar and charged patches, and comparison with the mu conotoxins provides a basis for determining the binding surface of the conotoxin GS polypeptide.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_9115446}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 9115446 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_9115446}} |
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| | ==About this Structure== | | ==About this Structure== |
| - | 1AG7 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Conus_geographus Conus geographus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AG7 OCA]. | + | 1AG7 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Conus_geographus Conus geographus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AG7 OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: Neurotoxin]] | | [[Category: Neurotoxin]] |
| | [[Category: Sodium channel blocker]] | | [[Category: Sodium channel blocker]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 10:13:40 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 16:46:54 2008'' |
Revision as of 13:46, 30 June 2008
Template:STRUCTURE 1ag7
CONOTOXIN GS, NMR, 20 STRUCTURES
Template:ABSTRACT PUBMED 9115446
About this Structure
1AG7 is a Single protein structure of sequence from Conus geographus. Full experimental information is available from OCA.
Reference
Solution structure of the sodium channel antagonist conotoxin GS: a new molecular caliper for probing sodium channel geometry., Hill JM, Alewood PF, Craik DJ, Structure. 1997 Apr 15;5(4):571-83. PMID:9115446
Page seeded by OCA on Mon Jun 30 16:46:54 2008
