DNA Concatamers by Rolling-Circle Amplification as Multivalent Inhibitors of Influenza A Virus Particles

The surfaces of influenza A virus (IAV) particles are packed with hundreds of homo-trimeric hemagglutinins (HAs). Monovalent sugars have low affinity for HA, but distance-optimized bivalent sialyl-LacNAc (SLN) conjugates bind it with 10(3)-fold enhanced potency. Herein, we describe the oligomerization of distance-optimized bivalent binders by branched and linear hybridization on long repetitive DNA templates. The most effective complexes fully inhibited IAVs at a DNA template concentration of 10(-9) m. Although a 10(-2) m concentration of free trisaccharide ligand is required for full inhibition of the virus, DNA templating enables a 10(4)-fold reduction in the amount of sugar required. Notably, hybridization-induced rigidification of the DNA templates increased the serospecificity. Cryo-TEM analysis revealed that both spaghetti-type linear forms and cotton-ball-like clusters are able to bridge several adjacent HA molecules on the IAV surface. Programmed self-assembly of ligand-nucleic acid conjugates on long DNA templates might provide generic access to target-specific, high-affinity binders of proteins on globular objects such as cells and viruses.