@article { ISI:000312940800010,
	title = {Structural Enzymology of Cellvibrio japonicus Agd31B Protein Reveals alpha-Transglucosylase Activity in Glycoside Hydrolase Family 31},
	journal = {JOURNAL OF BIOLOGICAL CHEMISTRY},
	volume = {287},
	number = {52},
	year = {2012},
	month = {DEC 21},
	pages = {43288-43299},
	type = {Article},
	abstract = {The metabolism of the storage polysaccharides glycogen and starch is of vital importance to organisms from all domains of life. In bacteria, utilization of these alpha-glucans requires the concerted action of a variety of enzymes, including glycoside hydrolases, glycoside phosphorylases, and transglycosylases. In particular, transglycosylases from glycoside hydrolase family 13 (GH13) and GH77 play well established roles in alpha-glucan side chain (de) branching, regulation of oligo-and polysaccharide chain length, and formation of cyclic dextrans. Here, we present the biochemical and tertiary structural characterization of a new type of bacterial 1,4-alpha-glucan 4-alpha-glucosyltransferase from GH31. Distinct from 1,4-alpha-glucan 6-alpha-glucosyltransferases (EC 2.4.1.24) and 4-alpha-glucanotransferases (EC 2.4.1.25), this enzyme strictly transferred one glucosyl residue from alpha(1 -> 4)-glucans in disproportionation reactions. Substrate hydrolysis was undetectable for a series of malto-oligosaccharides except maltose for which transglycosylation nonetheless dominated across a range of substrate concentrations. Crystallographic analysis of the enzyme in free, acarbose-complexed, and trapped 5-fluoro-beta-glucosyl-enzyme intermediate forms revealed extended substrate interactions across one negative and up to three positive subsites, thus providing structural rationalization for the unique, single monosaccharide transferase activity of the enzyme.},
	issn = {0021-9258},
	doi = {10.1074/jbc.M112.416511},
	author = {Larsbrink, Johan and Izumi, Atsushi and Hemsworth, Glyn R. and Davies, Gideon J. and Brumer, Harry}
}
