An Extracellular Disulfide Bond Forming Protein (DsbF) from Mycobacterium tuberculosis: Structural, Biochemical, and Gene Expression Analysis

JOURNAL OF MOLECULAR BIOLOGY

卷:396

Article

Chim, Nicholas¹  Riley, Robert²  The, Juliana³  Im, Soyeon³  Segelke, Brent⁴  Lekin, Tim⁴  Yu, Minmin⁵  Hung, Li We⁷  Terwilliger, Tom⁶  Whitelegge, Julian P.^8,9  Goulding, Celia W.^1,10 

[1] UCI, Dept Mol Biol & Biochem, Irvine, CA 92697 USA

[2] Univ Calif Los Angeles, David Geffen Sch Med, Dept Human Genet, Los Angeles, CA 90095 USA

[3] Univ Calif Los Angeles, DOE Inst Genom & Prote, Los Angeles, CA 90095 USA

[4] Lawrence Livermore Natl Lab, Biol & Biotechnol Program, Livermore, CA 94551 USA

[5] Univ Calif Berkeley, Lawrence Berkeley Lab, Phys Biosci Div, Berkeley, CA 94720 USA

[6] Los Alamos Natl Lab, Biosci Div, Los Alamos, NM 87545 USA

[7] Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA

[8] Univ Calif Los Angeles, Dept Chem & Biochem, Los Angeles, CA 90095 USA

[9] Univ Calif Los Angeles, Pasarow Mass Spectrometry Lab, NPI Semel Inst, David Geffen Sch Med, Los Angeles, CA 90095 USA

[10] UCI, Dept Pharmaceut Sci, Irvine, CA 92697 USA

关键词: Mycobacterium tuberculosis;    disulfide bond forming protein;    structure-function;    gene expression data;    X-ray crystallography;   

DOI  :  10.1016/j.jmb.2009.12.060

来源: Elsevier

【 摘 要 】

Disulfide bond forming (Dsb) proteins ensure correct folding and disulfide bond formation of secreted proteins. Previously, we showed that Mycobacterium tuberculosis DsbE (Mtb DsbE, Rv2878c) aids in vitro oxidative folding of proteins. Here, we present structural, biochemical, and gene expression analyses of another putative Mtb secreted disulfide bond isomerase protein homologous to Mtb DsbE, Mtb DsbF (Rv1677). The X, ray crystal structure of Mtb DsbF reveals a conserved thioredoxin fold although the active-site cysteines may be modeled in both oxidized and reduced forms, in contrast to the solely reduced form in Mtb DsbE. Furthermore, the shorter loop region in Mtb DsbF results in a more solvent-exposed active site. Biochemical analyses show that, similar to Mtb DsbE, Mtb DsbF can oxidatively refold reduced, unfolded hirudin and has a comparable pK(a) for the active-site solvent-exposed cysteine. However, contrary to Mtb DsbE, the Mtb DsbF redox potential is more oxidizing and its reduced state is more stable. From computational genomics analysis of the M. tuberculosis genome, we identified a potential Mtb DsbF interaction partner, Rv1676, a predicted peroxiredoxin. Complex formation is supported by protein coexpression studies and inferred by gene expression profiles, whereby Mtb DsbF and Rv1676 are upregulated under similar environments. Additionally, comparison of Mtb DsbF and Mtb DsbE gene expression data indicates anticorrelated gene expression patterns, suggesting that these two proteins and their functionally linked partners constitute analogous pathways that may function under different conditions. (C) 2010 Elsevier Ltd. All rights reserved.

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