Figure 8: Overlay of the tetrahedral intermediate (ASAtetr, gray bonds and black labels) produced in hiASADH and the acyl-enzyme intermediate (ASAacyl, magenta bonds and labels) obtained in spASADH. The change in geometry of the acyl carbon of this bound intermediate is tracked by shifts in the substrate binding groups, Asn127, Glu220, and Arg245. H. influenzae numbering is in parentheses.