FIG. 4.

Effect of Fe protein redox state on DRAT-dependent inactivation rate. K. pneumoniae cultures were derepressed for nitrogen fixation. Inactivation of nitrogenase was initiated by the addition of 0.5 mM ammonium acetate. Modification of Fe protein was monitored by anti-Fe protein immunoblotting. Traces represent data from UN5482 (draTGB, wild-type background) (⧫), UN5484 (nifD background) (◊), UN5485 (nifJ background) (■), and UN5486 (nifF background) (□). Data represent the averages from four experiments. The standard deviation for each datum point is <30%.