2ifi
From Proteopedia
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[[Image:2ifi.jpg|left|200px]] | [[Image:2ifi.jpg|left|200px]] | ||
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| - | + | {{STRUCTURE_2ifi| PDB=2ifi | SCENE= }} | |
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'''Ala6 Variant of ImI Conotoxin''' | '''Ala6 Variant of ImI Conotoxin''' | ||
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==About this Structure== | ==About this Structure== | ||
| - | + | Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IFI OCA]. | |
==Reference== | ==Reference== | ||
Protein folding determinants: structural features determining alternative disulfide pairing in alpha- and chi/lambda-conotoxins., Kang TS, Radic Z, Talley TT, Jois SD, Taylor P, Kini RM, Biochemistry. 2007 Mar 20;46(11):3338-55. Epub 2007 Feb 22. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17315952 17315952] | Protein folding determinants: structural features determining alternative disulfide pairing in alpha- and chi/lambda-conotoxins., Kang TS, Radic Z, Talley TT, Jois SD, Taylor P, Kini RM, Biochemistry. 2007 Mar 20;46(11):3338-55. Epub 2007 Feb 22. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17315952 17315952] | ||
| - | [[Category: Protein complex]] | ||
[[Category: Kang, T S.]] | [[Category: Kang, T S.]] | ||
[[Category: Kini, R M.]] | [[Category: Kini, R M.]] | ||
| - | [[Category: | + | [[Category: Conotoxin]] |
| - | [[Category: | + | [[Category: Disulfide linkage]] |
| - | [[Category: | + | [[Category: Ribbon conformation]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 07:26:52 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 04:26, 4 May 2008
Ala6 Variant of ImI Conotoxin
Overview
Alpha-conotoxins isolated from Conus venoms contain 11-19 residues and preferentially fold into the globular conformation that possesses a specific disulfide pairing pattern (C1-3, C2-4). We and others isolated a new family of chi-conotoxins (also called lambda conotoxins) with the conserved cysteine framework of alpha-conotoxins but with alternative disulfide pairing (C1-4, C2-3) resulting in the ribbon conformation. In both families, disulfide pairing and hence folding are important for their biological potency. By comparing the structural differences, we identified potential structural determinants responsible for the folding tendencies of these conotoxins. We examined the role of conserved proline in the first intercysteine loop and the conserved C-terminal amide on folding patterns of synthetic analogues of ImI conotoxin by comparing the isoforms with the regiospecifically synthesized conformers. Deamidation at the C-terminus and substitution of proline in the first intercysteine loop switch the folding pattern from the globular form of alpha-conotoxins to the ribbon form of chi/lambda-conotoxins. The findings are corroborated by reciprocal folding of CMrVIA chi/lambda-conotoxins. Substitution of Lys-6 from the first intercysteine loop of CMrVIA conotoxin with proline, as well as the inclusion of an amidated C-terminal shifted the folding preference of CMrVIA conotoxin from its native ribbon conformation toward the globular conformation. Binding assays of ImI conotoxin analogues with Aplysia and Bulinus acetylcholine binding protein indicate that both these substitutions and their consequent conformational change substantially impact the binding affinity of ImI conotoxin. These results strongly indicate that the first intercysteine loop proline and C-terminal amidation act as conformational switches in alpha- and chi/lambda-conotoxins.
About this Structure
Full crystallographic information is available from OCA.
Reference
Protein folding determinants: structural features determining alternative disulfide pairing in alpha- and chi/lambda-conotoxins., Kang TS, Radic Z, Talley TT, Jois SD, Taylor P, Kini RM, Biochemistry. 2007 Mar 20;46(11):3338-55. Epub 2007 Feb 22. PMID:17315952 Page seeded by OCA on Sun May 4 07:26:52 2008
