1xvq

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Revision as of 04:15, 21 November 2007

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

Crystal structure of thiol peroxidase from Mycobacterium tuberculosis

Overview

A thiol peroxidase (Tpx) from Mycobacterium tuberculosis was functionally, analyzed. The enzyme shows NADPH-linked peroxidase activity using a, thioredoxin-thioredoxin reductase system as electron donor, and, anti-oxidant activity in a thiol-dependent metal-catalyzed oxidation, system. It reduces H2O2, t-butyl hydroperoxide, and cumene hydroperoxide, and is inhibited by sulfhydryl reagents. Mutational studies revealed that, the peroxidatic (Cys60) and resolving (Cys93) cysteine residues are, critical amino acids for catalytic activity. The X-ray structure, determined to a resolution of 1.75 A shows a thioredoxin fold similar to, that of other peroxiredoxin family members. Superposition with structural, homologues in oxidized and reduced forms indicates that the M., tuberculosis Tpx is a member of the atypical two-Cys peroxiredoxin family., In addition, the short distance that separates the Calpha atoms of Cys60, and Cys93 and the location of these cysteine residues in unstructured, regions may indicate that the M. tuberculosis enzyme is oxidized, though, the side-chain of Cys60 is poorly visible. It is solely in the reduced, Streptococcus pneumoniae Tpx structure that both residues are part of two, distinct helical segments. The M. tuberculosis Tpx is dimeric both in, solution and in the crystal structure. Amino acid residues from both, monomers delineate the active site pocket.

About this Structure

1XVQ is a Single protein structure of sequence from Mycobacterium tuberculosis with YT3 and NH4 as ligands. Full crystallographic information is available from OCA.

Reference

Functional and structural characterization of a thiol peroxidase from Mycobacterium tuberculosis., Rho BS, Hung LW, Holton JM, Vigil D, Kim SI, Park MS, Terwilliger TC, Pedelacq JD, J Mol Biol. 2006 Sep 1;361(5):850-63. Epub 2006 Jun 27. PMID:16884737

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