Fig. 4.
The 2-OG effect on PII–NAGK complex dissociation. (A) SPR analysis of 2-OG-induced dissociation of NAGK–PII complex in the presence of 1 mM ATP. The response difference (ΔRU) between flow cells FC2 and FC1 (control) is shown. After binding of 100 nM PII to NAGK in FC2, a mixture of 1 mM ATP, 1 mM MgCl2, and 2-oxoglutarate [at a concentration of 0 (solid line), 0.5 (dotted line), 1 (dashed line), and 3 mM (dot-dashed line), as indicated] was injected at the point indicated by an arrow. (B) The effect of 2-OG on NAGK activity in the presence of 50 μM arginine. Increasing 2-OG concentrations were added to reaction mixtures after the formation of the PII–NAGK complex, and NAGK activity was determined as detailed in Materials and Methods. (Inset) Effect of 2-OG on NAGK activity in the presence of PII, when 2-OG was preincubated with PII.