Efficient biotransformation of naringenin to naringenin α-glucoside, a novel α-glucosidase inhibitor, by amylosucrase from <i>Deinococcus wulumuquiensis</i>

Abstract

Amylosucrase (ASase) efficiently biosynthesizes alpha-glucoside using flavonoids as acceptor molecules and sucrose as a donor molecule. Here, ASase from Deinococcus wulumuqiensis (DwAS) biosynthesized more naringenin alpha-glucoside (N alpha G) with sucrose and naringenin as donor and acceptor molecules, respectively, than other ASases from Deinococcus sp. The biotransformation rate of DwAS to N alpha G was 21.3% compared to 7.1-16.2% for other ASases. Docking simulations showed that the active site of DwAS was more accessible to naringenin than those of others. The 217th valine in DwAS corresponded to the 221 st isoleucine in Deinococcus geothermalis AS (DgAS), and the isoleucine possibly prevented naringenin from accessing the active site. The DwAS-V217I mutant had a significantly lower biosynthetic rate of N alpha G than DwAS. The k cat /K m value of DwAS with naringenin as the donor was significantly higher than that of DgAS and DwAS-V217I. In addition, N alpha G inhibited human intestinal alpha-glucosidase more efficiently than naringenin.