title: Expression of Klebsiella pneumoniae nitrogen fixation genes in nitrate reductase mutants of Escherichia coli.
abstract: Nitrate reductase (nar) A, B and E mutants of Escherichia coli with plasmids carrying Klebsiella pneumoniae nitrogen fixation (nif) genes reduced acetylene independently of added molybdate, but nar D mutants showed pleiotropic dependence on the concentration of added molybdate for expression of both nar and nif. No complementation of nar mutations by nif occurred; nitrite but not nitrate repressed nif in nar hosts. Derepression of nif occurred in molybdenum-deficient nar D (nif) strains since nitrogenase peptides were present. nifB mutants, thought to have a lesion in the pathway of molybdenum to nitrogenase, as well as nif deletion mutants, had normal nitrate reductase activity.
mesh_terms: D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology*; D005809:Genes, Regulator; D007711:Klebsiella pneumoniae / Q000378:metabolism*; D008982:Molybdenum / Q000378:metabolism; D009154:Mutation; D009565:Nitrate Reductases / Q000378:metabolism*; D009586:Nitrogen Fixation; D010957:Plasmids
chemical_list: D008982:Molybdenum; D009565:Nitrate Reductases