@article { ISI:000295927100032,
	title = {Mechanistic Analysis of Trehalose Synthase from Mycobacterium smegmatis},
	journal = {JOURNAL OF BIOLOGICAL CHEMISTRY},
	volume = {286},
	number = {41},
	year = {2011},
	month = {OCT 14},
	pages = {35601-35609},
	abstract = {Trehalose synthase (TreS) catalyzes the reversible interconversion of maltose and trehalose and has been shown recently to function primarily in the mobilization of trehalose as a glycogen precursor. Consequently, the mechanism of this intriguing isomerase is of both academic and potential pharmacological interest. TreS catalyzes the hydrolytic cleavage of alpha-aryl glucosides as well as alpha-glucosyl fluoride, thereby allowing facile, continuous assays. Reaction of TreS with 5-fluoroglycosyl fluorides results in the trapping of a covalent glycosyl-enzyme intermediate consistent with TreS being a member of the retaining glycoside hydrolase family 13 enzyme family, thus likely following a two-step, double displacement mechanism. This trapped intermediate was subjected to protease digestion followed by LC-MS/MS analysis, and Asp(230) was thereby identified as the catalytic nucleophile. The isomerization reaction was shown to be an intramolecular process by demonstration of the inability of TreS to incorporate isotope-labeled exogenous glucose into maltose or trehalose consistent with previous studies on other TreS enzymes. The absence of a secondary deuterium kinetic isotope effect and the general independence of k(cat) upon leaving group ability both point to a rate-determining conformational change, likely the opening and closing of the enzyme active site.},
	issn = {0021-9258},
	doi = {10.1074/jbc.M111.280362},
	author = {Zhang, Ran and Pan, Yuan T. and He, Shouming and Lam, Michael and Brayer, Gary D. and Elbein, Alan D. and Withers, Stephen G.}
}
