Molecular cloning and functional analysis of the cysG and nirB genes of Escherichia coli K12, two closely-linked genes required for NADH-dependent nitrite reductase activity.
We have cloned two genes, nirB+ and cysG+ which are required for NADH-dependent nitrite reductase to be active, from the 74 min region of the Escherichia coli chromosome. Restriction mapping and complementation analysis establish the gene order crp-nirB-cysG-aroB. Both genes are trans-dominant in merodiploids and, under some conditions, can be expressed independently. The cysG+ gene can be expressed from both high and low copy number plasmids carrying a 3.6 kb PstI-EcoRI restriction fragment. Attempts to sub-clone the nirB+ gene into pBR322 on a 14.5 kb EcoRI fragment were unsuccessful, but this fragment was readily sub-cloned into and expressed from the low copy number plasmid pLG338 (Stoker et al. 1982). Overproduction of the 88 kDa nitrite reductase apoprotein by strains carrying a functional nirB+ gene suggests that nirB is the structural gene for this enzyme.
Macdonald
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Cole
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D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005796:Genes; D005798:Genes, Bacterial; D005838:Genotype; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics*; D050898:Nitrite Reductase (NAD(P)H); D009572:Nitrite Reductases / Q000235:genetics*; D010641:Phenotype; D010957:Plasmids; D013045:Species Specificity
D009247:NADH, NADPH Oxidoreductases; D009572:Nitrite Reductases; D050898:Nitrite Reductase (NAD(P)H); D004262:DNA Restriction Enzymes