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1fgg
From Proteopedia
| 1fgg, resolution 2.30Å () | |||||||||
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| Sites: | , , , , , , and | ||||||||
| Ligands: | , , , | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
CRYSTAL STRUCTURE OF 1,3-GLUCURONYLTRANSFERASE I (GLCAT-I) COMPLEXED WITH GAL-GAL-XYL, UDP, AND MN2+
Human beta1,3-glucuronyltransferase I (GlcAT-I) is a central enzyme in the initial steps of proteoglycan synthesis. GlcAT-I transfers a glucuronic acid moiety from the uridine diphosphate-glucuronic acid (UDP-GlcUA) to the common linkage region trisaccharide Gal beta 1-3Gal beta 1-4Xyl covalently bound to a Ser residue at the glycosaminylglycan attachment site of proteoglycans. We have now determined the crystal structure of GlcAT-1 at 2.3 A in the presence of the donor substrate product UDP, the catalytic Mn(2+) ion, and the acceptor substrate analog Gal beta 1-3Gal beta 1-4Xyl. The enzyme is a alpha/beta protein with two subdomains that constitute the donor and acceptor substrate binding site. The active site residues lie in a cleft extending across both subdomains in which the trisaccharide molecule is oriented perpendicular to the UDP. Residues Glu(227), Asp(252), and Glu(281) dictate the binding orientation of the terminal Gal-2 moiety. Residue Glu(281) is in position to function as a catalytic base by deprotonating the incoming 3-hydroxyl group of the acceptor. The conserved DXD motif (Asp(194), Asp(195), Asp(196)) has direct interaction with the ribose of the UDP molecule as well as with the Mn(2+) ion. The key residues involved in substrate binding and catalysis are conserved in the glucuronyltransferase family as well as other glycosyltransferases.
Heparan/chondroitin sulfate biosynthesis. Structure and mechanism of human glucuronyltransferase I., Pedersen LC, Tsuchida K, Kitagawa H, Sugahara K, Darden TA, Negishi M, J Biol Chem. 2000 Nov 3;275(44):34580-5. PMID:10946001
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
1fgg is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
- Pedersen LC, Tsuchida K, Kitagawa H, Sugahara K, Darden TA, Negishi M. Heparan/chondroitin sulfate biosynthesis. Structure and mechanism of human glucuronyltransferase I. J Biol Chem. 2000 Nov 3;275(44):34580-5. PMID:10946001 doi:10.1074/jbc.M007399200
