title: Role of Azotobacter vinelandii FdxN in FeMo-co biosynthesis.
abstract: Biosynthesis of metal clusters for the nitrogenase component proteins NifH and NifDK involves electron donation events. Yet, electron donors specific to the biosynthetic pathways of the [4Fe-4S] cluster of NifH, or the P-cluster and the FeMo-co of NifDK, have not been identified. Here we show that an Azotobacter vinelandii mutant lacking fdxN was specifically impaired in FeMo-co biosynthesis. The ΔfdxN mutant produced 5-fold less NifB-co, an early FeMo-co biosynthetic intermediate, than wild type. As a consequence, it accumulated FeMo-co-deficient apo-NifDK and was impaired in NifDK activity. We conclude that FdxN plays a role in FeMo-co biosynthesis, presumably by donating electrons to support NifB-co synthesis by NifB. This is the first role in nitrogenase biosynthesis unequivocally assigned to any A. vinelandii ferredoxin.
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Pozuelo de Alarcón 28223, Madrid, Spain.
authors.forename: Emilio
authors.initials: E
authors.lastname: Jiménez-Vicente
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Pozuelo de Alarcón 28223, Madrid, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Navarro-Rodríguez
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Pozuelo de Alarcón 28223, Madrid, Spain.
authors.forename: César
authors.initials: C
authors.lastname: Poza-Carrión
authors.affiliation: Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid, Pozuelo de Alarcón 28223, Madrid, Spain. Electronic address: lm.rubio@upm.es.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Rubio
mesh_terms: D016948:Azotobacter vinelandii / Q000235:genetics / Q000378:metabolism; D053898:Biosynthetic Pathways; D004583:Electrons; D058085:Iron Compounds / Q000378:metabolism*; D008983:Molybdoferredoxin / Q000096:biosynthesis* / Q000235:genetics; D009154:Mutation; D009591:Nitrogenase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D058085:Iron Compounds; D008983:Molybdoferredoxin; C085381:NifB cofactor; D010088:Oxidoreductases; D009591:Nitrogenase; C029130:nitrogenase reductase
keywords: EPR; Ferredoxin; Iron-molybdenum cofactor; NifB; Nitrogenase