Crystal structure of beta 1,3-glucuronyltransferase I in complex with active donor substrate UDP-GlcUA.
Pedersen, L.C., Darden, T.A., Negishi, M.(2002) J Biol Chem 277: 21869-21873
- PubMed: 11950836 
- DOI: https://doi.org/10.1074/jbc.M112343200
- Primary Citation of Related Structures:  
1KWS - PubMed Abstract: 
Beta1,3-glucuronyltransferase (GlcAT-I) is an essential enzyme involved in heparan sulfate and chondroitin sulfate biosynthesis. GlcAT-I is an inverting glycosyltransferase that catalyzes the transfer of glucuronic acid (GlcUA) to the common growing linker region Galbeta1-3Galbeta1-4Xyl that is attached to a serine side chain of a core protein. Previously the structure of GlcAT-I has been solved in the presence of the donor product UDP and an acceptor analog Galbeta1-3Galbeta1-4Xyl (Pedersen, L. C., Tsuchida, K., Kitagawa, H., Sugahara, K., Darden, T. A. & Negishi, M. (2000) J. Biol. Chem. 275, 34580-34585). Here we report the x-ray crystal structure of GlcAT-I in complex with the complete donor UDP-GlcUA, thereby providing structures of an inverting glycosyltransferase in which both the complete donor and acceptor substrates are present in the active site. This structure supports the in-line displacement reaction mechanism previously proposed. It also provides information on the essential amino acid residues that determine donor substrate specificity.
Organizational Affiliation: 
Laboratory of Reproductive and Developmental Toxicology, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.