Cloning and sequencing of the nitrogenase structural genes nifHDK of Herbaspirillum seropedicae.
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.
Machado
I M
IM
Departamento de Bioquímica, Universidade Federal do Paraná, Curitiba, PR, Brasil.
Yates
M G
MG
Machado
H B
HB
Souza
E M
EM
Pedrosa
F O
FO
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
D009591:Nitrogenase; D003545:Cysteine