Design and synthesis of a novel ganglioside ligand for influenza A viruses.

A novel ganglioside bearing Neua2-3Gal and Neua2-6Gal structures as distal sequences was designed as a ligand for influenza A viruses. The efficient synthesis of the designed ganglioside was accomplished by employing the cassette coupling approach as a key reaction, which was executed between the non-reducing end of the oligosaccharide and the cyclic glucosylceramide moiety. Examination of its binding activity to influenza A viruses revealed that the new ligand is recognized by Neua2-3 and 2-6 type viruses.

Study on systematizing the synthesis of the a-series ganglioside glycans GT1a, GD1a, and GM1 using the newly developed N-Troc-protected GM3 and GalN intermediates.

A first systematic synthesis of the glycan parts of the a-series gangliosides (GT1a, GD1a, and GM1) utilizing the newly developed N-Troc-protected GM3 and galactosaminyl building blocks is described. The key processes, including the assembly of the GM2 sequence and its conversion into the 3-hydroxy acceptor, were facilitated mainly by the high degree of participation and chemoselective cleavability of the Troc group in the galactosaminyl unit. Furthermore, the novel GM2 acceptor served as a good coupling partner during glycosylation with galactosyl, sialyl galactosyl, and disialyl galactosyl donors, successfully producing the GM1, GD1a, and GT1a glycans.

Design and efficient synthesis of novel GM2 analogues with respect to the elucidation of the function of GM2 activator.

To elucidate the mechanism underlying the hydrolysis of the GalNAcbeta1-->4Gal linkage in ganglioside GM2 [GalNAcbeta1-->4(NeuAcalpha2-->3)Galbeta1-->4Glcbeta1-->1' Cer] by beta-hexosaminidase A (Hex A) with GM2 activator protein, we designed and synthesized two kinds of GM2 linkage analogues-6'-NeuAc-GM2 and alpha-GalNAc-GM2. In this paper, the efficient and systematic synthesis of these GM2 analogues was described. The highlight of our synthesis process is that the key intermediates, newly developed sialyllactose derivatives, were efficiently prepared in sufficient quantities; these derivatives directly served as highly reactive glycosyl acceptors and coupled with GalNTroc donors to furnish the assembly of GM2 tetrasaccharides in large quantities.

Design and synthesis of versatile ganglioside probes for carbohydrate microarrays.

A series of ganglioside GM1-, GM2-, and GM3-type probes, in which the ceramide portion is replaced with a glucose residue, were systematically synthesized based on a convergent synthetic method.