The molybdenum cofactor biosynthesis protein MobA from Rhodobacter capsulatus is required for the activity of molybdenum enzymes containing MGD, but not for xanthine dehydrogenase harboring the MPT cofactor

• Published in: FEMS microbiology letters 1999-05, Vol.174 (2), p.239-246
• Main Authors: Leimkühler, Silke, Klipp, Werner
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Biosynthesis; Blotting, Southern; Chromosome Mapping; Coenzymes - chemistry; Coenzymes - metabolism; Cofactors; Dehydrogenase; Dehydrogenases; DNA, Bacterial; E coli; Enzymes; Escherichia coli Proteins; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Guanine; Guanine Nucleotides - metabolism; Iron-Sulfur Proteins; Metabolism. Enzymes; Metalloproteins - metabolism; Microbiology; mob locus; Molecular Sequence Data; Molybdenum; Molybdenum - metabolism; Molybdenum cofactor biosynthesis; Molybdoenzyme; Molybdopterin; Molybdopterin guanine dinucleotide synthase; Mutagenesis, Insertional; Nitrate Reductase; Nitrate Reductases - chemistry; Nitrate Reductases - metabolism; Nitrates; Oxidoreductases - chemistry; Oxidoreductases - metabolism; Protein biosynthesis; Pteridines - metabolism; Pterins - metabolism; Reductases; Rhodobacter capsulatus; Rhodobacter capsulatus - enzymology; Rhodobacter capsulatus - genetics; Sulfurtransferases - metabolism; Xanthine dehydrogenase; Xanthine Dehydrogenase - chemistry; Xanthine Dehydrogenase - metabolism
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.1999.tb13574.x

Abstract The requirement of MobA for molybdoenzymes with different molybdenum cofactors was analyzed in Rhodobacter capsulatus. MobA is essential for DMSO reductase and nitrate reductase activity, both enzymes containing the molybdopterin guanine dinucleotide cofactor (MGD), but not for active xanthine dehydrogenase, harboring the molybdopterin cofactor. In contrast to the mob locus of Escherichia coli and R. sphaeroides, the mobB gene is not located downstream of mobA in R. capsulatus. The mobA gene is expressed constitutively at low levels and no increase in mobA expression could be observed even under conditions of high MGD demand.