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'''1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI''' | '''1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI''' | ||
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[[Category: Miller, R.]] | [[Category: Miller, R.]] | ||
[[Category: Weeks, C M.]] | [[Category: Weeks, C M.]] | ||
[[Category: | [[Category: A-conotoxin]] | ||
[[Category: | [[Category: Acetylcholine receptor antagonist]] | ||
[[Category: | [[Category: Crystal structure]] | ||
[[Category: | [[Category: Neurotoxin]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 09:38:01 2008'' | |||
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Revision as of 09:38, 2 May 2008
1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI
OverviewOverview
Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype.
About this StructureAbout this Structure
1A0M is a Single protein structure of sequence from Conus episcopatus. Full crystallographic information is available from OCA.
ReferenceReference
The 1.1 A resolution crystal structure of [Tyr15]EpI, a novel alpha-conotoxin from Conus episcopatus, solved by direct methods., Hu SH, Loughnan M, Miller R, Weeks CM, Blessing RH, Alewood PF, Lewis RJ, Martin JL, Biochemistry. 1998 Aug 18;37(33):11425-33. PMID:9708977 Page seeded by OCA on Fri May 2 09:38:01 2008