@article { ISI:000251274700012,
	title = {Glycosynthase activity of hybrid aspen xyloglucan endo-transglycosylase PttXET16-34 nucleophile mutants},
	journal = {ORGANIC \& BIOMOLECULAR CHEMISTRY},
	volume = {5},
	number = {24},
	year = {2007},
	pages = {3971-3978},
	type = {Article},
	abstract = {Glycosynthases are active-site mutants of glycoside hydrolases that catalyse glycosyl transfer using suitable activated donor substrates without competing product hydrolysis ( S. M. Hancock, M. D. Vaughan and S. G. Withers, Curr. Opin. Chem. Biol., 2006, 10, 509-519). Site-directed mutagenesis of the catalytic nucleophile, Glu-85, of a Populus tremula x tremuloides xyloglucan endo-transglycosylase (PttXET16-34, EC 2.4.1.207) into alanine, glycine, and serine yielded enzymes with glycosynthase activity. Product analysis indicated that PttXET16-34 E85A in particular was able to catalyse regio- and stereospecific homo- and hetero- condensations of alpha-xylogluco-oligosaccharyl fluoride donors XXXG alpha F andXLLG alpha F to produce xyloglucans with regular sidechain substitution patterns. This substrate promiscuity contrasts that of the Humicola insolens Ce17B E197A glycosynthase, which was not able to polymerise the di-galactosylated substrate XLLG alpha F. The production of the PttXET16-34 E85A xyloglucosynthase thus expands the repertoire of glycosynthases to include those capable of synthesising structurally homogenenous xyloglucans},
	issn = {1477-0520},
	doi = {10.1039/b714570e},
	author = {Piens, Kathleen and Henriksson, Anna-Maria and Gullfot, Fredrika and Lopez, Marie and Faure, Egis and Ibatullin, Farid M. and Teeri, Tuula T. and Driguez, Hugues and Brumer, Harry}
}
