FIG. 1.

Uridylylation of R. rubrum GlnB. GlnB (0.5 μM) was incubated in a uridylylation reaction mixture with 0.13 μM R. rubrum GlnD, 3 mM MnCl₂, 60 μM α-ketoglutarate, 2 mM ATP, and 0.5 mM UTP, supplemented with [α-³²P]UTP. Samples were withdrawn from the reaction mixtures after 0, 2, 5, 10, and 20 min of incubation and stopped by addition of SDS cocktail. The samples were subjected to SDS-PAGE and visualized by autoradiography in panel A or Western blotting in panel B, immunoblotted with antibodies against R. rubrum GlnB. In panel B, the lower band corresponds to unmodified GlnB and the upper to the modified form of GlnB.