Arginine-259 of UGT2B7 Confers UDP-Sugar Selectivity.

摘要: Enzymes of the human UDP-glycosyltransferase (UGT) superfamily typically catalyze covalent addition sugar moiety from a UDP-sugar cofactor to relatively low–molecular weight lipophilic compounds. Although UDP-glucuronic acid (UDP-GlcUA) is most commonly employed as by UGT1 and UGT2 family enzymes, UGT2B7 several other enzymes can use both UDP-GlcUA UDP-glucose (UDP-Glc), leading formation glucuronide glucoside conjugates. An investigation UGT2B7-catalyzed morphine glycosidation indicated that glucuronidation principal route metabolism because binding affinity higher than UDP-Glc. Currently, it unclear which residues in domain are responsible for preferential UDP-GlcUA. Here, molecular dynamics (MD) simulations were performed together with site-directed mutagenesis enzyme kinetic studies identify within site selective binding. MD demonstrated Arg259, located N-terminal domain, specifically interacts UDP-GlcUA, whereby side chain Arg259 H-bonds forms salt bridge carboxylate group glucuronic acid. Consistent simulations, substitution Leu resulted loss morphine, 4-methylumbelliferone, zidovudine activity, but glucosidation was preserved. SIGNIFICANCE STATEMENT Despite importance uridine diphosphate glycosyltransferase drug chemical metabolism, interactions incompletely understood, basis enzymes. The study long timescale homology model be used critical UGT protein cofactors. Further, data provide application elucidation UGT–aglycone interactions.