Reversible ADP-Ribosylation of Dinitrogenase Reductase from Rhodospirillum rubrum Regulates the Activity of the Enzyme In Vivo and In Vitro

The nitrogenase activity of Rhodospirillum rubrum is regulated by reversible mono(ADP-ribosyl)ation of the dinitrogenase reductase component of the enzyme (1, 2). R. rubrum is a gram-negative, non-sulfur photosynthetic bacterium that is capable of growth on N2 as the N-source in pure culture. The organism is capable of diverse modes of growth including anaerobic fermentation, aerobic respiration and anoxygenic photosynthesis.