2cpo

From Proteopedia

Revision as of 16:09, 5 November 2007

CHLOROPEROXIDASE

Overview

BACKGROUND: Chloroperoxidase (CPO) is a versatile heme-containing enzyme, that exhibits peroxidase, catalase and cytochrome P450-like activities in, addition to catalyzing halogenation reactions. The structure determination, of CPO was undertaken to help elucidate those structural features that, enable the enzyme to exhibit these multiple activities. RESULTS: Despite, functional similarities with other heme enzymes, CPO folds into a novel, tertiary structure dominated by eight helical segments. The catalytic, base, required to cleave the peroxide O-O bond, is glutamic acid rather, than histidine as in other peroxidases. CPO contains a hydrophobic patch, above the heme that could be the binding site for substrates that undergo, P450-like reactions. The crystal structure also shows extensive, glycosylation with both N- and O-linked glycosyl chains. CONCLUSIONS: The, proximal side of the heme in CPO resembles cytochrome P450 because a, cysteine residue serves as an axial heme ligand, whereas the distal side, of the heme is 'peroxidase-like' in that polar residues form the, peroxide-binding site. Access to the heme pocket is restricted to the, distal face such that small organic substrates can interact with the, iron-linked oxygen atom which accounts for the P450-like reactions, catalyzed by chloroperoxidase.

About this Structure

2CPO is a Single protein structure of sequence from Leptoxyphium fumago with NAG, MAN, MN and HEM as ligands. Active as Chloride peroxidase, with EC number 1.11.1.10 Structure known Active Sites: HE1, HEM, MN, NG1, NG2, NG3, OG1, OG2, OG3, OG4, OG5, OG6, OG7 and OG8. Full crystallographic information is available from OCA.

Reference

The crystal structure of chloroperoxidase: a heme peroxidase--cytochrome P450 functional hybrid., Sundaramoorthy M, Terner J, Poulos TL, Structure. 1995 Dec 15;3(12):1367-77. PMID:8747463

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