Abstract
Undec-10-enyl, undec-10-ynyl and 11-azidoundecyl glycoside analogues corresponding to the oligosaccharides of human gangliosides GM3, GM2 and GM1 were synthesized in high yields using glycosyltransferases from
Campylobacter jejuni. Due to poor water solubility of the substrates, the reactions were carried out in methanol–water media, which for the first time were shown to be compatible with the
C. jejuni α-(2→3)-sialyltransferase (CST-06) and β-(1→4)-
N-acetylgalactosaminyltransferase (CJL-30). Bioequivalence of our synthetic analogues and natural gangliosides was examined by binding to
Vibrio cholerae toxin and to the B subunit of
Escherichia coli heat-labile enterotoxin. This bioequivalence was confirmed by binding mouse and human monoclonal antibodies to GM1 and acute phase sera containing IgM and IgG antibodies to GM1 from patients with the immune-mediated polyneuropathy Guillain–Barré syndrome. The synthesized compounds were analyzed by 1D and 2D 900
MHz NMR spectroscopy. TOCSY and DQF-COSY experiments in combination with
13C–
1H correlation measurements (HSQC, HMBC) were carried out for primary structural characterization, and a complete assignment of all
1H and
13C chemical shifts is presented.