01948nas a2200217   4500008004100000245014600041210006900187260000800256300001400264490000700278520115500285100001801440700002101458700002001479700002701499700002301526700001501549700002101564700002101585856012401606       2017                        eng d00aGlucosylation of smoke-derived volatiles in grapevine (vitis vinifera) is catalyzed by a promiscuous resveratrol/guaiacol glucosyltransferase0 aGlucosylation of smokederived volatiles in grapevine vitis vinif  cJUL  a5681-56890 v653 aVinification of grapes (Vitis vinifera) exposed to forest fire smoke can yield unpalatable wine due to the presence of taint compounds from smoke and the release of smoke derived volatiles from their respective glycosides during the fermentation process or in-mouth during consumption. To identify glycosyltransferases (GTs) involved in the formation of glycosidically bound smoke-derived volatiles we performed gene expression analysis of candidate GTs in different grapevine tissues. Second, substrates derived from bushfire smoke or naturally occurring in grapes were screened with the candidate recombinant GTs. A resveratrol GT (UGT72B27) gene, highly expressed in grapevine leaves and berries was identified to be responsible for the production of the phenolic glucosides. UGT72B27 converted the stilbene trans-resveratrol mainly to the 3-O-glucoside. Kinetic analyses yielded specificity constants (k(cat)/K-m) of 114, 17, 9, 8, and 2 mM(-1) s(-1) for guaiacol, trans-resveratrol, syringol, methylsyringol, and methylguaiacol, respectively. This knowledge will help to design strategies for managing the risk of producing smoke-affected wines.1 aHaratl, Katja1 aHuang, Fong-Chin1 aGiri, Ashok, P.1 aFranz-Oberdorf, Katrin1 aFrotscher, Johanna1 aShao, Yang1 aHoffmann, Thomas1 aSchwab, Wilfried  uhttps://library.ncl.res.in/content/glucosylation-smoke-derived-volatiles-grapevine-vitis-vinifera-catalyzed-promiscuous02450nas a2200289   4500008004100000022001400041245012900055210006900184260000800253300001200261490000700273520149600280653001301776653002401789653002301813653001601836653001601852100001801868700002001886700002301906700001801929700002701947700001601974700002101990700002102011856012802032       2019                        eng d  a0959-665800aSemirational design and engineering of grapevine glucosyltransferases for enhanced activity and modified product selectivity0 aSemirational design and engineering of grapevine glucosyltransfe  cNOV  a765-7750 v293 a<p>Uridine diphosphate-dependent glycosyltransferases (UGTs) catalyze the transfer of a diversity of sugars to several acceptor molecules and often exhibit distinct substrate specificity. Modulation of glycosyltransferases for increased catalytic activity and altered substrate or product specificity are the key manipulations for the biotechnological use of glycosyltransferases in various biosynthetic processes. Here, we have engineered the binding pocket of three previously characterized Vitis vinifera glycosyltransferases, UGT88F12, UGT72B27 and UGT92G6, by structure-guided in silico mutagenesis to facilitate the interactions of active site residues with flavonol glucosides and thus modify substrate specificity and activity. Site-directed mutagenesis at selected sites, followed with liquid chromatography-mass spectrometry based activity assays, exhibited that mutant UGTs were altered in product selectivity and activity as compared to the wild-type enzymes. Mutant UGTs produced larger amounts of flavonol di-monosaccharide glucosides, which imply that the mutations led to structural changes that increased the volume of the binding pocket to accommodate a larger substrate and to release larger products at ease. Mutants showed increased activity and modified product specificity. Thus, structure-based systematic mutations of the amino acid residues in the binding pocket can be explored for the generation of engineered UGTs for diverse biotechnological applications.</p>
10aflavonol10aGlycosyltransferase10ain silico analysis10aMutagenesis10aselectivity1 aJoshi, Rakesh1 aTrinkl, Johanna1 aHaugeneder, Annika1 aHaertl, Katja1 aFranz-Oberdorf, Katrin1 aGiri, Ashok1 aHoffmann, Thomas1 aSchwab, Wilfried  uhttps://library.ncl.res.in/content/semirational-design-and-engineering-grapevine-glucosyltransferases-enhanced-activity-and