title: Nitrogenase switch-off by ammonium ions in Azospirillum brasilense requires the GlnB nitrogen signal-transducing protein.
abstract: Nitrogenase activity in several diazotrophs is switched off by ammonium and reactivated after consumption. The signaling pathway to this system in Azospirillum brasilense is not understood. We show that ammonium-dependent switch-off through ADP-ribosylation of Fe protein was partial in a glnB mutant of A. brasilense but absent in a glnB glnZ double mutant. Triggering of inactivation by anaerobic conditions was not affected in either mutant. The results suggest that glnB is necessary for full ammonium-dependent nitrogenase switch-off in A. brasilense.
authors.affiliation: Universidade Federal do Paraná, Departamento de Bioquímica e Biologia Molecular, Caixa Postal 19046 CEP-81531-990, Curitiba, Paraná, Brazil.
authors.forename: Giseli
authors.initials: G
authors.lastname: Klassen
authors.forename: Emanuel M
authors.initials: EM
authors.lastname: Souza
authors.forename: M Geoffrey
authors.initials: MG
authors.lastname: Yates
authors.forename: Liu Un
authors.initials: LU
authors.lastname: Rigo
authors.forename: Roberta M
authors.initials: RM
authors.lastname: Costa
authors.forename: Juliana
authors.initials: J
authors.lastname: Inaba
authors.forename: Fábio O
authors.initials: FO
authors.lastname: Pedrosa
mesh_terms: D015806:Azospirillum brasilense / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D009591:Nitrogenase / Q000235:genetics / Q000378:metabolism*; D051922:PII Nitrogen Regulatory Proteins; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D015398:Signal Transduction
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; C100965:GlnZ protein, Azospirillum brasilense; D051922:PII Nitrogen Regulatory Proteins; D000644:Quaternary Ammonium Compounds; C404143:PIID regulatory protein, Bacteria; D009591:Nitrogenase