Figure 2.

The enzyme adenylate kinase undergoes large, dynamic conformational changes during its catalytic cycle.A, proposed reaction scheme for the enzyme adenylate kinase (E) including the steps of substrate binding (k_on), lid closing (k_close), phosphotransfer (k_p-transfer), lid opening (k_open), and substrate dissociation (k_off). B, superposition of molecule A of apo Aquifex (red) with apo E. coli (blue) Adk reveals only small changes in the overall structure between the homologues, as indicated by the dashed ovals. C, superposition of apo Aquifex Adk (red) and Aquifex Adk in complex (green) with the substrate analog Zn^2+.Ap5A (shown as ball and stick in gray) demonstrates the closure of the ATP and AMP lids on substrate binding. Figure from (40).