Figure 4.
Stereoviews of superpositions of the active sites of the two subunits. The bonds of subunits A and B are shown in yellow and cyan, respectively, except for residues 303–305 which are shown in green (subunit A) and blue (subunit B). (A) Wild-type enzyme. (B) The enzyme after reduction of the Schiff base double bond by cyanoborohydride.