FIGURE 6.

Interactions between AmtB and GlnK in response to physiologically relevant concentrations of ATP, ADP, 2-OG, and Mg²⁺ effectors. A, purified His₆-AmtB-GlnK complex was applied to a HIS-Select spin column in the presence of different combinations of effectors. The effector concentrations used reflect the measured in vivo values at 30 s, 1 min, 2 min, 3 min, 5 min, 10 min, and 15 min post-ammonium shock (lanes A–G). Washed and eluted fractions were analyzed by 12.5% SDS-PAGE. The presence of GlnK in the washed fractions (W) indicates conditions under which GlnK dissociated from AmtB. Conversely, GlnK in the eluted fractions (E) indicates that the His₆-AmtB-GlnK complex remained associated. B, individual AmtB and GlnK proteins were applied to the column. The presence of GlnK in the eluted fractions indicates conditions under which GlnK associated with AmtB.