Effects of homocitrate, homocitrate lactone, and fluorohomocitrate on nitrogenase in NifV- mutants of Azotobacter vinelandii.
Azotobacter vinelandii DJ71, which contains a mutation in the nifV gene, was derepressed for nitrogenase in the presence of homocitrate. When dinitrogenase was isolated from this culture, it was found to be identical to the wild-type dinitrogenase. However, when the same NifV- strain was derepressed in the presence of erythrofluorohomocitrate, a homocitrate analog which produces a nitrogenase with wild-type properties in vitro, the isolated dinitrogenase was characteristic of the NifV- enzyme. These data show that homocitrate, but not fluorohomocitrate, is utilized by NifV- mutant cells. Fluorohomocitrate does not inhibit the uptake of homocitrate because the wild-type phenotype resulted when both compounds were added to the medium during nitrogenase derepression. Homocitrate lactone failed to cure the NifV- phenotype.
Madden
M S
MS
Department of Biochemistry, University of Wisconsin-Madison 53706.
Paustian
T D
TD
Ludden
P W
PW
Shah
V K
VK
D001395:Azotobacter / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D005798:Genes, Bacterial; D007783:Lactones / Q000494:pharmacology*; D009154:Mutation; D009586:Nitrogen Fixation / Q000235:genetics*; D009591:Nitrogenase / Q000235:genetics*; D010641:Phenotype; D014233:Tricarboxylic Acids / Q000494:pharmacology*
D007783:Lactones; D014233:Tricarboxylic Acids; C065595:1-fluorohomocitrate; C028143:homocitric acid; C070684:homocitrate lactone; D009591:Nitrogenase