1gx4
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| , resolution 1.46Å | |||||||
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| Sites: | |||||||
| Ligands: | , and | ||||||
| Activity: | Transferred entry: 2.4.1.87, with EC number 2.4.1.151 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
ALPHA-,1,3 GALACTOSYLTRANSFERASE- N-ACETYL LACTOSAMINE COMPLEX
OverviewOverview
Bovine alpha-1,3-galactosyltransferase (alpha3GT) catalyzes the synthesis of the alpha-galactose (alpha-Gal) epitope, the target of natural human antibodies. It represents a family of enzymes, including the histo blood group A and B transferases, that catalyze retaining glycosyltransfer reactions of unknown mechanism. An initial study of alpha3GT in a crystal form with limited resolution and considerable disorder suggested the possible formation of a beta-galactosyl-enzyme covalent intermediate (Gastinel, L. N., Bignon, C., Misra, A. K., Hindsgaul, O., Shaper, J. H., and Joziasse, D. H. (2001) EMBO J. 20, 638-649). Highly ordered structures are described for complexes of alpha3GT with donor substrate, UDP-galactose, UDP- glucose, and two acceptor substrates, lactose and N-acetyllactosamine, at resolutions up to 1.46 A. Structural and calorimetric binding studies suggest an obligatory ordered binding of donor and acceptor substrates, linked to a donor substrate-induced conformational change, and the direct participation of UDP in acceptor binding. The monosaccharide-UDP bond is cleaved in the structures containing UDP-galactose and UDP-glucose, producing non-covalent complexes containing buried beta-galactose and alpha-glucose. The location of these monosaccharides and molecular modeling suggest that binding of a distorted conformation of UDP-galactose may be important in the catalytic mechanism of alpha3GT.
About this StructureAbout this Structure
1GX4 is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis of ordered binding of donor and acceptor substrates to the retaining glycosyltransferase, alpha-1,3-galactosyltransferase., Boix E, Zhang Y, Swaminathan GJ, Brew K, Acharya KR, J Biol Chem. 2002 Aug 2;277(31):28310-8. Epub 2002 May 14. PMID:12011052
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