Transformation from block-type to graft-type oligonucleotide-glycopolymer conjugates by self-organization with half-sliding complementary oligonucleotides and their lectin recognition

Block-type oligonucleotide-glycopolymer conjugates bearing alpha -mannosides and beta -galactosides were prepared by coupling 5 ' -thiol-modified oligonucleotides with iodoacetamidated glycopolymers that were synthesized by telomerization. The conjugates minimally affected the DNA conformation and melting behavior of the duplex. Their self-organization via hybridization with the half-sliding complementary oligonucleotides produced graft-type conjugates or macromolecular gapped DNA duplexes grafted with glycopolymers at regular intervals, which was confirmed using size exclusion chromatography and electrophoresis. The binding affinity of block-type and self-organized graft-type conjugates to lectins was investigated using fluorometry. The affinity of the graft-type duplex assembly bearing mannosides to Con A was approximately 2 times stronger than that of block-type single-stranded or double-stranded conjugates with full complementary oligonucleotides. The organization strategy of DNA-glycopolymer conjugates might be useful for constructing novel glyco-clusters and also for developing a new methodology for gene therapy.