Disease relevance of narI

• Respiratory nitrate reductase purified from the cell membrane of Escherichia coli is composed of three subunits, alpha, beta, and gamma, which are encoded, respectively, by the narG, narH, and narI genes of the narGHJI operon [1].
• The existence of a nitrate-reductase operon in the tryptophane region was deduced from the effects of prophage insertion in each of chlI and chlC genes and from transposition of the Mu-mediated host DNA fragments of F-prime [2].

High impact information on narI

• The narJ and narI genes were subcloned separately into plasmids where each was under the control of the nar promoter [3].
• Expression of these plasmids in a mutant which forms only alpha and beta subunits revealed that expression of the narI gene is sufficient to restore normal levels of cytochrome bNR, but expression of both genes is required for assembly of fully active, membrane-bound nitrate reductase [3].
• The amino acid composition, the N-terminal sequence, and the sequence of cyanogen bromide fragments derived from the isolated gamma subunit corresponds to that expected for a protein produced by the narI ORF [3].
• The hemes of Escherichia coli nitrate reductase A (NarGHI): potentiometric effects of inhibitor binding to narI [4].
• 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 [5].

References