Structural and Functional Analysis of UGT92G6 Suggests an Evolutionary Link Between Mono- and Disaccharide Glycoside-Forming Transferases.

摘要: Glycosylation mediated by UDP-dependent glycosyltransferase (UGT) is one of the most common reactions for biosynthesis small molecule glycosides. As glycosides have various biological roles, we characterized UGT genes from grapevine (Vitis vinifera). In silico analysis VvUGT that were highly expressed in leaves identified UGT92G6 which showed sequence similarity to both monosaccharide and disaccharide glucoside-forming transferases. The recombinant glucosylated phenolics, among them caffeic acid, carvacrol, eugenol raspberry ketone, also accepted geranyl glucoside citronellyl glucoside. Thus, formed mono- diglucosides vitro distinct compounds. enzyme specificity constant Vmax/Km ratios indicated exhibited highest towards producing almost equal amounts 3- 4-O-glucoside. Transient overexpression Nicotiana benthamiana confirmed production caffeoyl glucoside; however, level diglucoside was not elevated upon UGT92G6, even after co-expression encoding geraniol synthase provide sufficient precursor. Comparative 3-D structure a motif characteristic monoglucoside-forming UGTs suggesting an evolutionary link between glycoside UGTs. functions as diglucosyltransferase vitro, but acts N. benthamiana.