1wct

From Proteopedia

Revision as of 03:11, 21 November 2007

A NOVEL CONOTOXIN FROM CONUS TEXTILE WITH UNUSUAL POST-TRANSLATIONAL MODIFICATIONS REDUCES PRESYNAPTIC CALCIUM INFLUX, NMR, 1 STRUCTURE, GLYCOSYLATED PROTEIN

Overview

Cone snails are gastropod mollusks of the genus Conus that live in, tropical marine habitats. They are predators that paralyze their prey by, injection of venom containing a plethora of small, conformationally, constrained peptides (conotoxins). We report the identification, characterization, and structure of a gamma-carboxyglutamic acid-containing, peptide, conotoxin epsilon-TxIX, isolated from the venom of the, molluscivorous cone snail, Conus textile. The disulfide bonding pattern of, the four cysteine residues, an unparalleled degree of posttranslational, processing including bromination, hydroxylation, and glycosylation define, a family of conotoxins that may target presynaptic Ca2+ channels or act on, G protein-coupled presynaptic receptors via another mechanism. This, conotoxin selectively reduces neurotransmitter release at an Aplysia, cholinergic synapse by reducing the presynaptic influx of Ca2+ in a slow, and reversible fashion. The three-dimensional structure, determined by, two-dimensional 1H NMR spectroscopy, identifies an electronegative patch, created by the side chains of two gamma-carboxyglutamic acid residues that, extend outward from a cavernous cleft. The glycosylated threonine and, hydroxylated proline enclose a localized hydrophobic region centered on, the brominated tryptophan residue within the constrained intercysteine, region.

About this Structure

1WCT is a Single protein structure of sequence from Conus textile. Full crystallographic information is available from OCA.

Reference

A conotoxin from Conus textile with unusual posttranslational modifications reduces presynaptic Ca2+ influx., Rigby AC, Lucas-Meunier E, Kalume DE, Czerwiec E, Hambe B, Dahlqvist I, Fossier P, Baux G, Roepstorff P, Baleja JD, Furie BC, Furie B, Stenflo J, Proc Natl Acad Sci U S A. 1999 May 11;96(10):5758-63. PMID:10318957

Page seeded by OCA on Wed Nov 21 05:18:49 2007