title: Effect of amino acid substitutions in a potential metal-binding site of AnfA on expression from the anfH promoter in Azotobacter vinelandii.
abstract: AnfA, an activator required for transcription of the structural genes encoding nitrogenase 3 (anfHDGK) in Azotobacter vinelandii, has a potential metal-binding site [(S19)H(C21)FTGE(C26)R] in its N terminus. Growth studies and expression of an anfH-lacZ fusion in mutants containing amino acid substitutions in this site indicate that Ser-19 is not required for AnfA activity whereas Cys-21 and Cys-26 are required. Residual expression of the anfH-lacZ fusion in AnfA- mutants was found to be due to activation by VnfA, the activator required for expression of genes encoding nitrogenase 2.
authors.affiliation: Agricultural Research Service, U.S. Department of Agriculture, Raleigh, North Carolina.
authors.forename: R
authors.initials: R
authors.lastname: Premakumar
authors.forename: T M
authors.initials: TM
authors.lastname: Loveless
authors.forename: P E
authors.initials: PE
authors.lastname: Bishop
mesh_terms: D001395:Azotobacter / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D001426:Bacterial Proteins; D001483:Base Sequence; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D008982:Molybdenum / Q000378:metabolism; D009591:Nitrogenase / Q000096:biosynthesis / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015534:Trans-Activators / Q000235:genetics*; D014158:Transcription, Genetic; D014639:Vanadium / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D014639:Vanadium; D008982:Molybdenum; D009591:Nitrogenase; C070293:nitrogenase 3