Molecular switch manipulating Prelog priority of an alcohol dehydrogenase toward bulky-bulky ketones

Structure-guided rational design revealed the molecular switch manipulating the Prelog and anti-Prelog priorities of an NADPH-dependent alcohol dehydrogenase toward prochiral ketones with bulky and similar substituents. Synergistic effects of unconserved residues at 214 and 237 in small and large substrate binding pockets were proven to be vital in governing the stereoselectivity. The ee values of E214Y/S237A and E214C/S237 G toward (4-chlorophenyl)-(pyridin-2-yl)-methanone were 99.3% ( R ) and 78.8% ( S ) respectively. Substrate specificity analysis revealed that similar patterns were also found with (4’-chlorophenyl)-phenylmethanone, (4’-bromophenyl)-phenylmethanone and (4’-nitrophenyl)-phenylmethanone. This study provides valuable evidence for understanding the molecular mechanism on enantioselective recognition of prochiral ketones by alcohol dehydrogenase.