B. Kim, S. Sung, N. Jung
May 1, 2010
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0
Influential Citations
15
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Journal
Journal of Molecular Catalysis B-enzymatic
Abstract
The gene for one of the glycosyltransferases from Populus deltoids, PGT-3, was cloned and was expressed as a glutathione S-transferase fusion protein in Escherichia coli. Various flavonoids were used as potential substrates of the purified recombinant PGT-3. Flavones having two adjacent hydroxyl groups were served as substrate. The regioselectivity of PGT-3 depends on the hydroxyl groups of the substrate. Flavones having two adjacent hydroxyl groups in the B ring were glucosylated at the 4′-hydroxyl group. However, PGT-3 transferred a glucose group to the 3-hydroxyl group of isorhamnetin. Molecular modeling and docking and site-directed mutagenesis were carried out to engineer a PGT-3 having a specificity for isorhamnetin but not for quercetin. Glu82Leu turned out to display this activity. Using the Glu82Leu mutant and a quercetin 3′-O-methyltransferase, isorhamnetin 3-O-glucoside was synthesized.