Figure 63.

Stereoview of the simulated annealing omit map showing the binding of an aza analogue of the final carbocation intermediate (compound 4 in Figure 60) in the active site of aristolochene synthase. Metal coordination and hydrogen bond interactions are indicated by red and black dashed lines, respectively. The orientation of the analogue is close to that modeled in Figure 62 based on the three-dimensional productlike contour of the enclosed active site (the view here is rotated ca. 180° relative to that in Figure 62). Water molecule “w” (red sphere hydrogen bonded to N213, N299, and S303) remains trapped in the active site in all structures of enzyme-ligand complexes. Reproduced from ref (24). Copyright 2013 American Chemical Society.