
Full text loading...
Summary: Mutants have been isolated which lack NADH-dependent nitrite reductase activity but retain NADPH-dependent sulphite reductase and formate hydrogenlyase activities. These NirB−strains synthesize cytochrome c 552 and grow normally on anaerobic glyeerol–fumarate plates. The defects map in a gene, nir B, which is extremely close to cysG, the gene order being crp, nirB, cysG, aroB. Complementation studies established that nirB + and cysG + canbe expressed independently. The data strongly suggest that nirB is the structural gene for the 88 kDal NADH-dependent nitrite oxidoreductase apoprotein (EC 1.6.6.4).
The nirB gene is apparently defective in the previously described nirD mutant, LCB82. The nirH mutant, LCB197, was unable to use formate as electron donor for nitrite reduction, but NADH-dependent nitrite reductase was extremely active in this strain and a normal content of cytochrome c 552 was detected. Strains carrying a nirE, nirF or nirG mutation gavenormal rates of nitrite reduction by glucose, formate or NADH.
Article metrics loading...
Full text loading...
References
Data & Media loading...