1d2v

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Revision as of 14:21, 12 November 2007

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spinqualitylabelsall models 1d2v, resolution 1.75Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF BROMIDE-BOUND HUMAN MYELOPEROXIDASE ISOFORM C AT PH 5.5

Contents 1 Overview 2 Disease 3 About this Structure 4 Reference

Overview

The x-ray crystal structure of human myeloperoxidase has been extended to, 1.8 A resolution, using x-ray data recorded at -180 degrees C (r = 0.197, free r = 0.239). Results confirm that the heme is covalently attached to, the protein via two ester linkages between the carboxyl groups of Glu(242), and Asp(94) and modified methyl groups on pyrrole rings A and C of the, heme as well as a sulfonium ion linkage between the sulfur atom of, Met(243) and the beta-carbon of the vinyl group on pyrrole ring A. In the, native enzyme a bound chloride ion has been identified at the amino, terminus of the helix containing the proximal His(336). Determination of, the x-ray crystal structure of a myeloperoxidase-bromide complex (r =, 0.243, free r = 0.296) has shown that this chloride ion can be replaced by, bromide. Bromide is also seen to bind, at partial occupancy, in the distal, heme cavity, in close proximity to the distal His(95), where it replaces, the water molecule hydrogen bonded to Gln(91). The bromide-binding site in, the distal cavity appears to be the halide-binding site responsible for, shifts in the Soret band of the absorption spectrum of myeloperoxidase. It, is proposed that halide binding to this site inhibits the enzyme by, effectively competing with H(2)O(2) for access to the distal histidine, whereas in compound I, the same site may be the halide substrate-binding, site.

Disease

Known diseases associated with this structure: Alzheimer disease, susceptibility to OMIM:[606989], Lung cancer, protection against, in smokers OMIM:[606989], Myeloperoxidase deficiency OMIM:[606989]

About this Structure

1D2V is a Single protein structure of sequence from Homo sapiens with NAG, CA, BR, SO4, ACT and HEM as ligands. Active as Peroxidase, with EC number 1.11.1.7 Full crystallographic information is available from OCA.

Reference

X-ray crystal structure and characterization of halide-binding sites of human myeloperoxidase at 1.8 A resolution., Fiedler TJ, Davey CA, Fenna RE, J Biol Chem. 2000 Apr 21;275(16):11964-71. PMID:10766826

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