Biosynthesis of iron-molybdenum cofactor in the absence of nitrogenase.

摘要: Klebsiella pneumoniae accumulates molybdenum during nitrogenase derepression. The is primarily in component I the form of iron-molybdenum cofactor (FeMo-co). Mutations any three genes (nifB, nifN, and nifE) involved biosynthesis FeMo-co resulted very low accumulation a molybdenum-free I. A mutant lacking both subunits accumulated 60% amount present wild type. was protein-bound behaved differently than that type with respect to electrophoretic mobility, size, extractability by organic solvents. Two forms could be extracted from protein fraction mutant; one them not detected type, other like nonaqueous gel filtration chromatography. Crude extracts this were able complement vitro K. or Azotobacter vinelandii mutants unable produce FeMo-co. These data show does require presence In its absence, on different protein, presumably an intermediate normal biosynthetic pathway.