Open AccessMolybdate‐dependent expression of dimethylsulfoxide reductase in Rhodobacter capsulatus
Author(s) -
Solomon Peter S.,
Shaw Anthony L.,
Young Michael D.,
Leimkuhler Silke,
Hanson Graeme R.,
Klipp Werner,
McEwan Alastair G.
Publication year - 2000
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2000.tb09287.x
Subject(s) - rhodobacter , operon , nitrate reductase , molybdenum cofactor , biochemistry , reductase , molybdate , biology , chemistry , gene , enzyme , escherichia coli , mutant , inorganic chemistry
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.