@article { ISI:000188005700049,
	title = {The donor subsite of trehalose-6-phosphate synthase - Binary complexes with UDP-glucose and UDP-2-deoxy-2-fluoro-glucose at 2 angstrom resolution},
	journal = {JOURNAL OF BIOLOGICAL CHEMISTRY},
	volume = {279},
	number = {3},
	year = {2004},
	month = {JAN 16},
	pages = {1950-1955},
	abstract = {Trehalose is an unusual non-reducing disaccharide that plays a variety of biological roles, from food storage to cellular protection from environmental stresses such as desiccation, pressure, heat-shock, extreme cold, and oxygen radicals. It is also an integral component of the cell-wall glycolipids of mycobacteria. The primary enzymatic route to trehalose first involves the transfer of glucose from a UDP-glucose donor to glucose-6-phosphate to form alpha,alpha-1,1 trehalose-6-phosphate. This reaction, in which the configurations of two glycosidic bonds are set simultaneously, is catalyzed by the glycosyltransferase trehalose-6-phosphate synthase ( OtsA), which acts with retention of the anomeric configuration of the UDP-sugar donor. The classification of activated sugar-dependent glycosyltransferases into approximately 70 distinct families based upon amino acid sequence similarities places OtsA in glycosyltransferase family 20 (see afmb.cnrs-mrs.fr/CAZY/). The recent 2.4 Angstrom structure of Escherichia coli OtsA revealed a two-domain enzyme with catalysis occurring at the interface of the twin beta/alpha/beta domains. Here we present the 2.0 Angstrom structures of the E. coli OtsA in complex with either UDP-Glc or the non-transferable analogue UDP-2-deoxy-2-fluoroglucose. Both complexes unveil the donor subsite interactions, confirming a strong similarity to glycogen phosphorylases, and reveal substantial conformational differences to the previously reported complex with UDP and glucose 6-phosphate. Both the relative orientation of the two domains and substantial ( up to 10 Angstrom) movements of an N-terminal loop ( residues 9 - 22) characterize the more open {\textquoteleft}{\textquoteleft}relaxed{{\textquoteright}{\textquoteright}} conformation of the binary UDP-sugar complexes reported here.},
	issn = {0021-9258},
	doi = {10.1074/jbc.M307643200},
	author = {Gibson, RP and Tarling, CA and Roberts, S and Withers, SG and Davies, GJ}
}
