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1uqu
From Proteopedia
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TREHALOSE-6-PHOSPHATE FROM E. COLI BOUND WITH UDP-GLUCOSE.
Overview
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 A 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 A 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 A) movements of, an N-terminal loop (residues 9-22) characterize the more open "relaxed", conformation of the binary UDP-sugar complexes reported here.
About this Structure
1UQU is a Single protein structure of sequence from Escherichia coli with UPG as ligand. Active as Alpha,alpha-trehalose-phosphate synthase (UDP-forming), with EC number 2.4.1.15 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
The donor subsite of trehalose-6-phosphate synthase: binary complexes with UDP-glucose and UDP-2-deoxy-2-fluoro-glucose at 2 A resolution., Gibson RP, Tarling CA, Roberts S, Withers SG, Davies GJ, J Biol Chem. 2004 Jan 16;279(3):1950-5. Epub 2003 Oct 21. PMID:14570926
Page seeded by OCA on Tue Dec 18 18:07:29 2007
