FIG. 2.

Role of AmtB and AmtY in the membrane sequestration of GlnB and GlnK. Two parallel cultures of the R. capsulatus wild type (B10S) and amtB (RCAY63) and amtY (RCAY22) mutants were grown under N₂-fixing conditions. NH₄Cl (1 mM) was added to one of the parallel cultures 15 min prior to harvest. Cytoplasmic (C) and membrane (M) fractions were subjected to SDS-PAGE (5 μg of total protein was loaded per well) followed by Western blotting with anti-GlnB (A) or anti-GlnK antibody (B). Wild-type (B10S) cells grown under N₂-fixing conditions was collected 30 min after being exposed to darkness. Cytoplasmic and membrane fractions were subjected to SDS-PAGE (5 μg of total protein was loaded per well) and Western blotting with anti-GlnB or anti-GlnK antibody (C).