Nitrogenase activity of Herbaspirillum seropedicae grown under low iron levels requires the products of nifXorf1 genes.
Herbaspirillum seropedicae strains mutated in the nifX or orf1 genes showed 90% or 50% reduction in nitrogenase activity under low levels of iron or molybdenum respectively. Mutations in nifX or orf1 genes did not affect nif gene expression since a nifH::lacZ fusion was fully active in both mutants. nifX and the contiguous gene orf1 are essential for maximum nitrogen fixation under iron limitation and are probably involved in synthesis of nitrogenase iron or iron-molybdenum clusters.
Klassen
Giseli
G
Departamento de Patologia Básica, Universidade Federal do Paraná, CP 19046, 81531-990 Curitiba PR, Brazil. giseli@ufpr.br
de Oliveira Pedrosa
Fábio
F
de Souza
Emanuel M
EM
Yates
M Geoffrey
MG
Rigo
Liu Un
LU
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020562:Betaproteobacteria / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D005798:Genes, Bacterial; D007501:Iron / Q000378:metabolism*; D007763:Lac Operon; D008982:Molybdenum / Q000378:metabolism; D009586:Nitrogen Fixation / Q000235:genetics / Q000502:physiology*; D009591:Nitrogenase / Q000378:metabolism*; D010957:Plasmids
D001426:Bacterial Proteins; C118795:NifX protein, Bacteria; D008982:Molybdenum; D007501:Iron; D009591:Nitrogenase