title: The mobA gene is required for assimilatory and respiratory nitrate reduction but not xanthine dehydrogenase activity in Pseudomonas aeruginosa.
abstract: The requirement for the mobA gene in key assimilatory and respiratory nitrogen metabolism of Pseudomonas aeruginosa PAO1 was investigated by mutational analysis of PA3030 (mobA; MoCo guanylating enzyme), PA1779 (nasA; assimilatory nitrate reductase), and PA3875 (narG; respiratory nitrate reductase). The mobA mutant was deficient in both assimilatory and respiratory nitrate reductase activities, whereas xanthine dehydrogenase activity remained unaffected. Thus, P. aeruginosa requires both the molybdopterin (MPT) and molybdopterin guanine dinucleotide (MGD) forms of the molybdenum cofactor for a complete spectrum of nitrogen metabolism, and one form cannot substitute for the other. Regulation studies using a Phi(PA3030-lacZGm) reporter strain suggest that expression of mobA is not influenced by the type of nitrogen source or by anaerobiosis, whereas assimilatory nitrate reductase activity was detected only in the presence of nitrate.
authors.affiliation: Department of Biology, University of Dayton, Dayton, OH 45469, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Noriega
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Hassett
authors.forename: John J
authors.initials: JJ
authors.lastname: Rowe
mesh_terms: D000693:Anaerobiosis; D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D016254:Mutagenesis, Insertional; D009566:Nitrates / Q000378:metabolism*; D010084:Oxidation-Reduction; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014968:Xanthine Dehydrogenase / Q000235:genetics / Q000502:physiology*; D001616:beta-Galactosidase / Q000032:analysis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D009566:Nitrates; D015534:Trans-Activators; D014968:Xanthine Dehydrogenase; D001616:beta-Galactosidase