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| [[Image:1uqu.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1uqu| PDB=1uqu | SCENE= }} | | {{STRUCTURE_1uqu| PDB=1uqu | SCENE= }} |
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| '''TREHALOSE-6-PHOSPHATE FROM E. COLI BOUND WITH UDP-GLUCOSE.'''
| | ===TREHALOSE-6-PHOSPHATE FROM E. COLI BOUND WITH UDP-GLUCOSE.=== |
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| ==Overview==
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| 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.
| | The line below this paragraph, {{ABSTRACT_PUBMED_14570926}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 14570926 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_14570926}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Synthase]] | | [[Category: Synthase]] |
| [[Category: Transferase]] | | [[Category: Transferase]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 11:33:44 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 14:47:36 2008'' |
