Molybdate-dependent expression of dimethylsulfoxide reductase in Rhodobacter capsulatus

• Published in: FEMS microbiology letters Vol. 190; no. 2; pp. 203 - 208
• Main Authors: Solomon, Peter S., Shaw, Anthony L., Young, Michael D., Leimkuhler, Silke, Hanson, Graeme R., Klipp, Werner, McEwan, Alastair G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.09.2000; Blackwell; Oxford University Press
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Carrier Proteins; Dimethylsulfoxide reductase; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Bacterial; Genetics; Homology; Iron-Sulfur Proteins; Lac Operon - physiology; Light intensity; Luminous intensity; Membrane Transport Proteins; Microbiology; Molybdate; Molybdate‐dependent gene expression; Molybdenum; Molybdenum - metabolism; mop genes; Mutation; Nitrate reductase; Nitrate Reductases - metabolism; Nitrogen fixation; Nitrogenation; Operon - genetics; Oxidoreductases - genetics; Oxidoreductases - metabolism; Periplasm - enzymology; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Reductases; Rhodobacter; Rhodobacter capsulatus; Rhodobacter capsulatus - enzymology; Rhodobacter capsulatus - genetics; Substrates; Transcription; Transcription, Genetic; Xanthine dehydrogenase; Xanthine Oxidase - metabolism; Dimethylsulfoxide reductase; genes; Molybdate-dependent gene expression; Rhodobacter capsulatus; Rhodospirillales; Regulation(control); Enzyme; Nitrogen fixation; Bacteria; Environmental factor; Rhodospirillaceae; Gene expression; Molybdates; Rhodospirillineae
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2000.tb09287.x

Abstract Expression of the dimethylsulfoxide respiratory (dor) operon of Rhodobacter is regulated by oxygen, light intensity and availability of substrate. Since dimethylsulfoxide reductase contains a pterin molybdenum cofactor, the role of molybdate in the regulation of dor operon expression was investigated. In this report we show that the molybdate-responsive transcriptional regulator, MopB, and molybdate are essential for maximal dimethylsulfoxide reductase activity and expression of a dorA::lacZ transcriptional fusion in Rhodobacter capsulatus. In contrast, mop genes are not required for the expression of the periplasmic nitrate reductase or xanthine dehydrogenase in R. capsulatus under conditions of molybdenum sufficiency. This is the first report demonstrating a clear functional difference between the ModE homologues MopB and MopA in this bacterium. The results suggest that MopA is primarily involved in the regulation of nitrogen fixation gene expression in response to molybdate while MopB has a role in nitrogen fixation and dimethylsulfoxide respiration.