Figure 2: Ribbon drawing and surface rendering of the ASADH from Escherichia coli showing the overall structure. Each of the ASADH structures shares a conserved domain organization and exists as a functional homodimer. The largest structural differences between the different branches of this enzyme family manifest themselves in the coenzyme binding loop and in the helical subdomain bridging the dimerization interface. The bound coenzyme NADP and the active site amino acids are shown in one subunit as blue sticks.