title: Function of the Rhizobium etli CFN42 nirK gene in nitrite metabolism.
abstract: Rhizobium etli CFN42 is not capable of growing anaerobically with nitrate but it grows with nitrite as a terminal electron acceptor. This bacterium contains the nirK gene encoding the copper-containing Nir (nitrite reductase), which is located on the cryptic plasmid pCFN42f. Mutational analysis has demonstrated that a nirK deficient mutant was not capable of growing under nitrite-respiring conditions. Moreover, microaerobic growth of this mutant was inhibited by the presence of nitrite. Nir activity and nitrite uptake were highly diminished in a nirK mutant, compared with the wild-type levels after incubation under anaerobic conditions. Our results suggest that the copper-containing Nir may have both a respiratory and a nitrite-detoxifying role in R. etli.
authors.affiliation: Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC, P.O. Box 419, 18080 Granada, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Bueno
authors.forename: N
authors.initials: N
authors.lastname: Gómez-Hernández
authors.forename: L
authors.initials: L
authors.lastname: Girard
authors.forename: E J
authors.initials: EJ
authors.lastname: Bedmar
authors.forename: M J
authors.initials: MJ
authors.lastname: Delgado
mesh_terms: D005798:Genes, Bacterial; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000235:genetics / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D042163:Rhizobium etli / Q000235:genetics*
chemical_list: D009573:Nitrites; D009565:Nitrate Reductases; D050901:Nitrate Reductase