Highly Efficient Chemoenzymatic Synthesis of α-Galactosyl Epitopes with a Recombinant α(1→3)-Galactosyltransferase

• Published in: Journal of the American Chemical Society Vol. 120; no. 27; pp. 6635 - 6638
• Main Authors: Fang, Jianwen, Li, Jun, Chen, Xi, Zhang, Yingnan, Wang, Jianqiang, Guo, Zhengmao, Zhang, Wei, Yu, Libing, Brew, Keith, Wang, Peng George
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 15.07.1998; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; XENOTRANSPLANTATION; OLIGOSACCHARIDES; ENZYME; URIDINE 5'-DIPHOSPHATE GALACTOSE; GALACTOSYLTRANSFERASE; CATALYZED SYNTHESIS; REGENERATION; SEQUENCE; N-ACETYLLACTOSAMINE; ALPHA-1->3-GALACTOSYLTRANSFERASE
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja9808898

α-Galactosyl epitopes are carbohydrate structures bearing a Galα1-3Galβ terminus. The interaction of these epitopes on the surface of animal cells with anti-α-galactosyl antibodies in human serum is believed to be the main cause in antibody-mediated hyperacute rejection in xenotransplantation. This report describes an efficient chemoenzymatic approach based on the use of recombinant α(1→3)-galactosyltransferase (α1,3-GalT) for the synthesis of xenoactive α-galactosyl epitopes, which are highly desired in the research of xenotransplantation and immunotherapy. A truncated bovine α1,3-GalT (80−368) was cloned into the pET15b vector and subsequently transformed into E. coli BL21 strain. This expression system efficiently produced the soluble recombinant enzyme on a large scale with highly specific activity. A variety of α(1→3)-galactosylated epitopes were synthesized using such a recombinant enzyme. In a unique fashion, α-galactosyl pentasaccharide was synthesized via a one-pot, two-step enzymatic synthesis with in situ cofactor regeneration.