FIG 2.

Protein-protein interaction-dependent activation of NagB in the presence of a nonsaturating concentration of the allosteric effector, GlcNAc-6P (0.4 mM). (A) Activity was measured at 5 mM GlcN-6P in the presence of NanE (0.7 μM), PII (GlnB; 1 μM), and/or HPr (0.5 μM), BglA (0.2 μM), and Tsf (2 μM). The latter two proteins were included as negative controls (NC). (B) Activity was measured at 2 mM GlcN-6P in the presence of HPr (0.5 μM), U-PII (0.05 μM), or a combination of the same concentrations of HPr and U-PII at pH 7.5.