title: Cloning and sequencing of the nitrogenase structural genes nifHDK of Herbaspirillum seropedicae.
abstract: The nitrogenase structural genes (nifHDK) of the endophytic diazotroph Herbaspirillum seropedicae were isolated from a genomic bank by plate hybridization. Sequence analysis of the DNA showed a consensus promoter region upstream for the nifH gene containing a -24/-12 type promoter together with NifA- and integration host factor (IHF)- binding sites. The derived protein sequences of NifH, NifD and NifK contained conserved cysteine residues for binding iron-sulfur clusters and the iron-molybdenum cofactor. These protein sequences showed the strongest similarities to the nifHDK gene products of the symbiotic diazotroph Bradyrhizobium japonicum (93.5%, 91.3% and 83.3%, respectively), the plant-associated diazotroph Azospirillum brasilense (90.0%, 83.7% and 75.1%, respectively) and to Thiobacillus ferrooxidans (91.0%, 83.4% and 81.1%, respectively) of the same phylogenetic group of the protobacteria.
authors.affiliation: Departamento de Bioquímica, Universidade Federal do Paraná, Curitiba, PR, Brasil.
authors.forename: I M
authors.initials: IM
authors.lastname: Machado
authors.forename: M G
authors.initials: MG
authors.lastname: Yates
authors.forename: H B
authors.initials: HB
authors.lastname: Machado
authors.forename: E M
authors.initials: EM
authors.lastname: Souza
authors.forename: F O
authors.initials: FO
authors.lastname: Pedrosa
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003545:Cysteine / Q000302:isolation & purification; D005798:Genes, Bacterial; D006090:Gram-Negative Bacteria / Q000235:genetics*; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics*; D009591:Nitrogenase / Q000235:genetics*; D016366:Open Reading Frames; D017422:Sequence Analysis, DNA
chemical_list: D009591:Nitrogenase; D003545:Cysteine