Chemoenzymatic synthesis of 2-azidoethyl-ganglio-oligosaccharides GD3, GT3, GM2, GD2, GT2, GM1, and GD1a
作者:Ola Blixt、Daniela Vasiliu、Kirk Allin、Nathan Jacobsen、Dawn Warnock、Nahid Razi、James C. Paulson、Stéphane Bernatchez、Michel Gilbert、Warren Wakarchuk
DOI:10.1016/j.carres.2005.06.008
日期:2005.9
We have synthesized several ganglio-oligosaccharide structures using glycosyltransferases from Campylobacter jejuni. The enzymes, alpha-(2 -> 3/8)-sialyltransferase (Cst-II), beta-(1 -> 4)-N-acetylgalactosaminyltransferase (CgtA), and beta-(1 -> 3)-galactosyltransferase (CgtB), were produced in large-scale fermentation from Escherichia coli and further characterized based on their acceptor specificities. 2-Azidoethyl-glycosides corresponding to the oligosaccharides of GD3 (alpha-(D)-Neup5Ac-(2 -> 8)-alpha-(D)-Neup5Ac-(2 -> 3)-beta-(D)-Galp-(1 -> 4) -beta-(D)-Glcp-), GT3 (alpha-(D)-Neup5Ac-(2 -> 8)-alpha-(D)-Neup5Ac-(2 -> 8)-alpha-(D)-Neup5Ac-(2 -> 3)-beta-(D)-Galp-(1 -> 4)-beta-(D)-Glcp-), GM2 (beta-(D)-GalpNAc-(1 -> 4)-[alpha-(D)-Neup5Ac-(2 -> 3)]-beta-(D)-Galp-(1 -> 4)-beta-(D)-Glcp-), GD2 (beta-(D)-GalpNAc-(1 -> 4)-[alpha-(D)-Neup5Ac-(2 -> 8)-alpha-(D)-Neup5Ac-(2 -> 3)]-beta-(D)-Galp-(1 -> 4)-beta-(D)-Glcp-), GT2 (beta-(D)-GalpNAc-(1 -> 4)-[(alpha-(D)-Neup5Ac-(2 -> 8)]-beta-(D)-Neup5Ac-(2 -> 8)-alpha-(D)-Neup5Ac-(2 -> -> 3)beta-(D)-Galp-(1 -> 4)-beta-(D)-Glcp-), and GM1 (beta-(D)-Galp-(1 -> 3)-beta-(D)-GalpNAc-(1 -> 4)-[alpha-(D)-Neup5Ac-(2 -> 3)]-beta-(D)-Galp(1 -> 4)-beta-(D)-Glcp-) were synthesized in high yields (gram-scale). In addition, a mammalian a-(2 3)-sialyltransferase (ST3Gal 1) was used to sialylate GM1 and generate GD1a (alpha-(D)-Neup5Ac-(2 -> 3)-beta-(D)-Galp-(1 -> 3)-beta-(D)-GalpNAc-(1 -> 4)-[alpha-(D)-Neup5Ac-(2 -> 3)]-beta-(D)-Galp-(1 -> 4)-beta-(D)-Glcp-) oligosaccharide. We also cloned and expressed a rat UDP-N-acetylglucosamine-4 '-epimerase (GaINAcE) in E. coli AD202 cells for cost saving in situ conversion of less expensive UDP-GIcNAc to UDP-GaINAc. (c) 2005 Elsevier Ltd. All rights reserved.