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Characterization and mutagenesis of Gal/GlcNAc-6-O-sulfotransferases
被引:11
作者:
Grunwell, JR
Rath, VL
Rasmussen, J
Cabrilo, Z
Bertozzi, CR
[1
]
机构:
[1] Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA
[2] Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA
[3] Univ Calif Berkeley, Howard Hughes Med Inst, Berkeley, CA 94720 USA
[4] Thios Pharmaceut Inc, Emeryville, CA 94608 USA
关键词:
D O I:
10.1021/bi0269557
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
The installation of sulfate groups on the carbohydrate residues of glycoproteins, glycolipids, and glycosaminoglycans is a critical posttranslational modification that occurs in all higher eukaryotes. The Gal/GalNAc/GlcNAc-6-O-sulfotransferases (GSTs) are a recently discovered family of carbohydrate sulfotransferases that share significant sequence homology at the amino acid level and mediate a number of different biological processes such as leukocyte adhesion at sites of chronic inflammation. Structural and mechanistic studies of this family of sulfotransferases have been hindered by the lack of a productive recombinant protein expression system. We developed a baculovirus expression system for five of the seven cloned GSTs and determined their kinetic parameters using both thin-layer chromatography and a recently developed polymer dot-blot assay. We used these tools to perform the first site-directed mutagenesis study of a member of this sulfotransferase family, GST2. Using sequence alignments with other carbohydrate and cytosolic sulfotransferases, we selected residues within the putative binding regions for 3'-phosphoadenosine 5'-phosphosulfate (PAPS) and the carbohydrate substrate for mutagenesis. Kinetic analysis of the mutants identified residues that are essential for catalytic activity. These results should facilitate mechanistic studies and the development of small molecule inhibitors of this enzyme family to ameliorate chronic inflammatory diseases.
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页码:15590 / 15600
页数:11
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