Activation of Inactive Nitrogenase by Acid-Treated Component I

H. H. Nagatani, Vinod K. Shah, Winston J. Brill
1974 Journal of Bacteriology  
When Azotobacter vinelandii was derepressed for nitrogenase synthesis in a N-free medium containing tungstate instead of molybdate, an inactive component I was synthesized. Although this inactive component I could be activated in vivo upon addition of molybdate to the medium, it could not be activated in vitro when molybdate was added to the extracts. Activation occurred, however, when an acid-treated component I was added to extracts of cells derepressed in medium containing tungstate. Acid
more » ... tungstate. Acid treatment completely abolished component I activity. Mutant strains UW45 and UW10 were unable to fix N2. Both strains synthesized normal levels of component II but produced inactive component I. Acid-treated component I activated inactive component I in extracts of mutant strain UW45 but not mutant strain UW10. This activating factor could be obtained from N2-fixing Klebsiella pneumoniae, Clostridium pasteurianum, and Rhodospirillum rubrum.
doi:10.1128/jb.120.2.697-701.1974 fatcat:rigbw3tpv5bm5cohxsyzjjx7na