1lu4

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Template:STRUCTURE 1lu4

1.1 ANGSTROM RESOLUTION CRYSTAL STRUCTURE OF A SECRETED MYCOBACTERIUM TUBERCULOSIS DISULFIDE OXIDOREDUCTASE HOMOLOGOUS TO E. COLI DSBE: IMPLICATIONS FOR FUNCTIONS

Overview

Mycobacterium tuberculosis, a Gram-positive bacterium, encodes a secreted Dsb-like protein annotated as Mtb DsbE (Rv2878c, also known as MPT53). Because Dsb proteins in Escherichia coli and other bacteria seem to catalyze proper folding during protein secretion and because folding of secreted proteins is thought to be coupled to disulfide oxidoreduction, the function of Mtb DsbE may be to ensure that secreted proteins are in their correctly folded states. We have determined the crystal structure of Mtb DsbE to 1.1 A resolution, which reveals a thioredoxin-like domain with a typical CXXC active site. These cysteines are in their reduced state. Biochemical characterization of Mtb DsbE reveals that this disulfide oxidoreductase is an oxidant, unlike Gram-negative bacteria DsbE proteins, which have been shown to be weak reductants. In addition, the pK(a) value of the active site, solvent-exposed cysteine is approximately 2 pH units lower than that of Gram-negative DsbE homologs. Finally, the reduced form of Mtb DsbE is more stable than the oxidized form, and Mtb DsbE is able to oxidatively fold hirudin. Structural and biochemical analysis implies that Mtb DsbE functions differently from Gram-negative DsbE homologs, and we discuss its possible functional role in the bacterium.

About this Structure

1LU4 is a Single protein structure of sequence from Mycobacterium tuberculosis. Full crystallographic information is available from OCA.

Reference

Gram-positive DsbE proteins function differently from Gram-negative DsbE homologs. A structure to function analysis of DsbE from Mycobacterium tuberculosis., Goulding CW, Apostol MI, Gleiter S, Parseghian A, Bardwell J, Gennaro M, Eisenberg D, J Biol Chem. 2004 Jan 30;279(5):3516-24. Epub 2003 Nov 3. PMID:14597624 Page seeded by OCA on Sat May 3 00:17:33 2008