1gx4: Difference between revisions
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==Overview== | ==Overview== | ||
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, ... | 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 Structure== | ==About this Structure== | ||
1GX4 is a | 1GX4 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with MN, UDP and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Transferred_entry:_2.4.1.87 Transferred entry: 2.4.1.87], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.151 2.4.1.151] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GX4 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
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