LAUSR

Abstract Candida antarctica lipase B (CAL-B) exhibits extraordinary enantioselectivity towards most chiral sec-alcohols but not towards sec-alcohols bearing substituents smaller than a propyl group (i.e., (±)-but-3-yn-2-ol (E = 4) and (±)-butan-2-ol (E = 7)). Previously, we reported a homologous enzyme (lipase from Pseudozyma brasiliensis GHG001, PBL) of CAL-B, which exhibited high enantioselectivity of CAL-B towards (±)-but-3-yn-2-ol (E > 200). Based on the result, we hypothesized that the comparison of their local sequence or structure would provide a clue for enhancing the enantioselectivity of CAL-B. In this paper, we report enhancing enantioselectivity of CAL-B towards (±)-but-3-yn-2-ol and (±)-butan-2-ol through the substitution of the local sequence of CAL-B with that of PBL. The sequence-substituted mutant of CAL-B exhibited much higher enantioselectivity towards (±)-but-3-yn-2-ol (E > 200) and (±)-butan-2-ol (E > 25).