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3cu0

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==Overview==
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{{ABSTRACT_18400750}}
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Sulfated glycosaminoglycans (GAGs), including heparan sulfate and chondroitin sulfate, are synthesized on the so-called common GAG-protein linkage region (GlcUAss1-3Galss1-3Galss1-4Xylss1-O-Ser) of core proteins, which is formed by the stepwise addition of monosaccharide residues by the respective specific glycosyltransferases. Glucuronyltransferase-I (GlcAT-I) is the key enzyme that completes the synthesis of this linkage region, which is a prerequisite for the conversion of core proteins to functional proteoglycans bearing GAGs. The Xyl and Gal residues in the linkage region can be modified by phosphorylation and sulfation, respectively, although the biological significance of these modifications remains to be clarified. Here we present evidence that these modifications can significantly influence the catalytic activity of GlcAT-I. Enzyme assays showed that the synthetic substrates, Gal-Gal-Xyl(2-O-phosphate)-O-Ser and Gal-Gal(6-O-sulfate)-Xyl(2-O-phosphate)-O-Ser, served as better substrates than the unmodified compound, whereas Gal(6-O-sulfate)-Gal-Xyl(2-O-phosphate)-O-Ser exhibited no acceptor activity. The crystal structure of the catalytic domain of GlcAT-I with UDP and Gal-Gal(6-O-sulfate)-Xyl(2-O-phosphate)-O-Ser bound revealed that the Xyl(2-O-phosphate)-O-Ser is disordered and the 6-O-sulfate forms interactions with Q318 from the second GlcAT-I monomer in the dimeric enzyme. The results indicate the possible involvement of these modifications in the processing and maturation of the growing linkage region oligosaccharide required for the assembly of GAG chains.
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==About this Structure==
==About this Structure==
3CU0 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3CU0 OCA].
3CU0 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3CU0 OCA].
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==Reference==
 
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2-O-phosphorylation of xylose and 6-O-sulfation of galactose in the protein linkage region of glycosaminoglycans influence the glucuronyltransferase-I activity involved in the linkage region's synthesis., Tone Y, Pedersen LC, Yamamoto T, Izumikawa T, Kitagawa H, Nishihara J, Tamura JI, Negishi M, Sugahara K, J Biol Chem. 2008 Apr 9;. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18400750 18400750]
 
[[Category: Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase]]
[[Category: Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase]]
[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
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[[Category: Transmembrane]]
[[Category: Transmembrane]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 25 15:15:11 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 25 18:44:59 2008''

Revision as of 15:45, 25 June 2008

Image:3cu0.png

Template:STRUCTURE 3cu0

human beta 1,3-glucuronyltransferase I (GlcAT-I) in complex with UDP and GAL-GAL(6-SO4)-XYL(2-PO4)-O-SER


Template:ABSTRACT 18400750

About this Structure

3CU0 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Page seeded by OCA on Wed Jun 25 18:44:59 2008

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