title: Close genetic relationship between Nitrobacter hamburgensis nitrite oxidoreductase and Escherichia coli nitrate reductases.
abstract: The nitrite oxidoreductase (NOR) from the facultative nitrite-oxidizing bacterium Nitrobacter hamburgensis X14 was investigated genetically. In order to develop a probe for the gene norB, the N-terminal amino acid sequence of the NOR beta-subunit (NorB) was determined. Based on that amino acid sequence, an oligonucleotide was derived that was used for the identification and cloning of gene norB. Sequence analysis of DNA fragments revealed three adjacent open reading frames in the order norA, norX, norB. The DNA sequences of norX and norB represented complete genes while the open reading frame of norA was truncated by the cloning site. The deduced amino acid sequence of protein NorB contained four cysteine clusters with striking homology to those of iron-sulfur centers of bacterial ferredoxins. NorB shares significant sequence similarity to the beta-subunits (NarH, NarY) of the two dissimilatory nitrate reductases (NRA, NRZ) of Escherichia coli. Additionally, the derived amino acid sequence of the truncated open reading frame of norA showed striking resemblance to the alpha-subunits (NarG, NarZ) of the E. coli nitrate reductases.
authors.affiliation: Abteilung Mikrobiologie, Universität Hamburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Kirstein
authors.forename: E
authors.initials: E
authors.lastname: Bock
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D015342:DNA Probes; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D009565:Nitrate Reductases / Q000235:genetics*; D009572:Nitrite Reductases / Q000235:genetics*; D009576:Nitrobacter / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D015342:DNA Probes; D009565:Nitrate Reductases; D009572:Nitrite Reductases