Functional and structural analysis of members of the TorD family, a large chaperone family dedicated to molybdoproteins

• Published in: Microbiology (Society for General Microbiology) Vol. 150; no. 4; pp. 935 - 943
• Main Authors: Ilbert, Marianne, Mejean, Vincent, Iobbi-Nivol, Chantal
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.04.2004; Society for General Microbiology
• Subjects: Bacteriology; Biological and medical sciences; Dimerization; Enzyme Activation; Escherichia coli; Escherichia coli - enzymology; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli - metabolism; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - classification; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Iron-Sulfur Proteins - chemistry; Iron-Sulfur Proteins - genetics; Iron-Sulfur Proteins - metabolism; Metabolism. Enzymes; Microbiology; Molecular Chaperones - chemistry; Molecular Chaperones - classification; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Molybdenum - metabolism; Oxidoreductases - chemistry; Oxidoreductases - genetics; Oxidoreductases - metabolism; Oxidoreductases, N-Demethylating - chemistry; Oxidoreductases, N-Demethylating - genetics; Oxidoreductases, N-Demethylating - metabolism; Phylogeny; Substrate Specificity; Methyl sulfoxide; Enzyme; Secretion; Chaperone; Escherichia coli; Bacteria; Oxidoreductases; Phylogeny; Molybdenum; Enterobacteriaceae; Reductase
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.26909-0

Laboratoire de Chimie Bactérienne, Institut de Biologie Structurale et Microbiologie, Centre National de la Recherche Scientifique, 31, chemin Joseph Aiguier, 13402 Marseille Cedex 20, France Correspondence Chantal Iobbi-Nivol iobbi{at}ibsm.cnrs-mrs.fr The trimethylamine N -oxide (TMAO) reductase TorA, a DMSO reductase family member, is a periplasmic molybdoenzyme of Escherichia coli . The cytoplasmic protein TorD acts as a chaperone for TorA, allowing the efficient insertion of the molybdenum cofactor into the apoform of the enzyme prior to its secretion. This paper demonstrates that TorD is a member of a large family of prokaryotic proteins that are structurally related. Moreover, their genes generally belong to operons also encoding molybdoenzymes of the DMSO reductase family. Both the TorD and the DMSO reductase families present a similar phylogenetic organization, suggesting a co-evolution of these two families of proteins. This hypothesis is also supported by the fact that the TorD and DmsD chaperones cannot replace each other and thus appear dedicated to specific molybdopartners. Interestingly, it was found that the positive effect of TorD on TorA maturation, and the partial inhibitory effect of DmsD and homologues, are independent of the TorA signal sequence. Abbreviations: bis(MGD)Mo, bis(molybdopterine guanine dinucleotide)molybdenum; CD, circular dichroism; TMAO, trimethylamine N -oxide