Rigid helical poly(glycosyl phenyl isocyanide)s: Synthesis, conformational analysis, and recognition by lectins

Glycosylated poly(phenyl isocyanide)s were synthesized in an attempt to elucidate the effect of three-dimensionally regulated saccharide arrays along highly stereoregular polymer backbones on molecular recognition. Poly(phenyl isocyanide)s substituted with a-D-glucose, P-D-glucose, P-D-galactose, and p-lactose were obtained by polymerization of the corresponding acetylated glycosyl phenyl isocyanides with a Ni(II) catalyst and subsequent deacetylation. Helical main chains and spatially regulated saccharide arrays of the poly(phenyl isocyanide)s were demonstrated by CD spectroscopy and molecular dynamics calculations. Their binding affinity with lectins was investigated by inhibition of hemagglutination and fluorescence spectroscopy. The rigid cylindrical phenyl isocyanide glycopolymers exhibited little specific interactions with lectins, which was in contrast to the highly specific interactions of the multivalent glycoclusters along flexible phenylacrylamide glycopolymers. It has been demonstrated that the compatibility of orientation and spacing of clustered saccharide chains of glycopolymers is essential for specific molecular recognition by lectin.