title: narI region of the Escherichia coli nitrate reductase (nar) operon contains two genes.
abstract: In previous studies it has been established that in Escherichia coli the three known subunits of anaerobic nitrate reductase are encoded by the narGHI operon. From the nucleotide sequence of the narI region of the operon we conclude that, in addition to the narG and narH genes, the nar operon contains two other open reading frames (ORFs), ORF1 and ORF2, that encode proteins of 26.5 and 25.5 kilodaltons, respectively. Protein fusions to each of the genes in the operon showed that expression of all four genes was similarly regulated. The reading frames of ORF1 and ORF2 were verified, and the N-terminal sequence for the ORF1 fusion protein was determined. The nar operon therefore contains four genes designated and ordered as narGHJI.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical School, Houston 77025.
authors.forename: E J
authors.initials: EJ
authors.lastname: Sodergren
authors.forename: J A
authors.initials: JA
authors.lastname: DeMoss
mesh_terms: D000693:Anaerobiosis; D001483:Base Sequence; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D050901:Nitrate Reductase; D009565:Nitrate Reductases / Q000235:genetics*; D009566:Nitrates / Q000378:metabolism; D009876:Operon; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid; D014169:Transformation, Bacterial; D001616:beta-Galactosidase / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; D009565:Nitrate Reductases; D050901:Nitrate Reductase; D004262:DNA Restriction Enzymes; D001616:beta-Galactosidase