2h7z

From Proteopedia

Revision as of 06:12, 13 February 2008

Crystal structure of irditoxin

Overview

Boiga dendrophila (mangrove catsnake) is a colubrid snake that lives in, Southeast Asian lowland rainforests and mangrove swamps and that preys, primarily on birds. We have isolated, purified, and sequenced a novel, toxin from its venom, which we named denmotoxin. It is a monomeric, polypeptide of 77 amino acid residues with five disulfide bridges. In, organ bath experiments, it displayed potent postsynaptic neuromuscular, activity and irreversibly inhibited indirectly stimulated twitches in, chick biventer cervicis nerve-muscle preparations. In contrast, it induced, much smaller and readily reversible inhibition of electrically induced, twitches in mouse hemidiaphragm nerve-muscle preparations. More precisely, the chick muscle alpha(1)betagammadelta-nicotinic acetylcholine receptor, was 100-fold more susceptible compared with the mouse receptor. These data, indicate that denmotoxin has a bird-specific postsynaptic activity. We, chemically synthesized denmotoxin, crystallized it, and solved its crystal, structure at 1.9 A by the molecular replacement method. The toxin, structure adopts a non-conventional three-finger fold with an additional, (fifth) disulfide bond in the first loop and seven additional residues at, its N terminus, which is blocked by a pyroglutamic acid residue. This is, the first crystal structure of a three-finger toxin from colubrid snake, venom and the first fully characterized bird-specific toxin. Denmotoxin, illustrates the relationship between toxin specificity and the primary, prey type that constitutes the snake's diet.

About this Structure

2H7Z is a Protein complex structure of sequences from Boiga irregularis. Full crystallographic information is available from OCA.

Reference

Denmotoxin, a three-finger toxin from the colubrid snake Boiga dendrophila (Mangrove Catsnake) with bird-specific activity., Pawlak J, Mackessy SP, Fry BG, Bhatia M, Mourier G, Fruchart-Gaillard C, Servent D, Menez R, Stura E, Menez A, Kini RM, J Biol Chem. 2006 Sep 29;281(39):29030-41. Epub 2006 Jul 24. PMID:16864572

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