title: In vitro synthesis of the iron-molybdenum cofactor of nitrogenase.
abstract: Molybdate- and ATP-dependent in vitro synthesis of the iron-molybdenum cofactor (FeMo-co) of nitrogenase requires the protein products of at least the nifB, nifN, and nifE genes. Extracts of FeMo-co-negative mutants of Klebsiella pneumoniae and Azotobacter vinelandii with lesions in different genes can be complemented for FeMo-co synthesis. Both K. pneumoniae and A. vinelandii dinitrogenase (component I) deficient in FeMo-co can be activated by FeMo-co synthesized in vitro. Properties of the partially purified dinitrogenase activated by FeMo-co synthesized in vitro were comparable to those of dinitrogenase from the wild-type organism; e.g., ratios of acetylene- to nitrogen-reduction activities, as well as those of acetylene reduction activities to EPR spectrum peak height at g = 3.65, were very similar. A. vinelandii mutants UW45 and CA30 have mutations in a gene functionally equivalent to nifB of K. pneumoniae.
mesh_terms: D000114:Acetylene / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001395:Azotobacter / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002474:Cell-Free System; D002701:Chloramphenicol / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D004789:Enzyme Activation; D005288:Ferredoxins / Q000096:biosynthesis*; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D008982:Molybdenum / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008983:Molybdoferredoxin / Q000096:biosynthesis* / Q000235:genetics; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000235:genetics* / Q000378:metabolism; D009876:Operon; D011499:Protein Processing, Post-Translational; D014414:Tungsten / Q000494:pharmacology; D017973:Tungsten Compounds; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D005288:Ferredoxins; D008983:Molybdoferredoxin; D017973:Tungsten Compounds; D014639:Vanadium; C044659:molybdate; D014638:Vanadates; D002701:Chloramphenicol; D008982:Molybdenum; D000255:Adenosine Triphosphate; C020809:tetrathiomolybdate; D009591:Nitrogenase; D000114:Acetylene; C045951:tungstate; D014414:Tungsten