Sialic acid and sialyl‐lactose glyco‐conjugates: design, synthesis and binding assays to lectins and swine influenza H1N1 virus

The terminal parts of the influenza hemagglutinin (HA) receptors α 2,6‐ and α 2,3‐sialyllactoses were conjugated to an artificial carrier, named sequential oligopeptide carrier (SOC 4 ), to formulate human and avian receptor mimics, respectively. SOC 4 , formed by the tripeptide unit Lys‐Aib‐Gly, adopts a rigid helicoids‐type conformation, which enables the conjugation of biomolecules to the Lys‐N ε H 2 groups. By doing so, it preserves their initial conformations and functionalities of the epitopes. We report that SOC 4 ‐glyco‐conjugate bearing two copies of the α 2,6‐sialyllactose is specifically recognized by the biotinylated Sambucus nigra (elderberry) bark lectin, which binds preferentially to sialic acid in an α 2,6‐linkage. SOC 4 ‐glyco‐conjugate bearing two copies of the α 2,3‐sialyllactose was not recognized by the biotinylated Maackia amurensis lectin, despite its well‐known α 2,3‐sialyl bond specificity. However, preliminary immune blot assays showed that H1N1 virus binds to both the SOC 4 ‐glyco‐conjugates immobilized onto nitrocellulose membrane. It is concluded that Ac‐SOC 4 [(Ac) 2 ,(3′SL‐Aoa) 2 ]‐NH 2 5 and Ac‐SOC 4 [(Ac) 2 ,(6′SL‐Aoa) 2 ]‐NH 2 6 mimic the HA receptors. These findings could be useful for easy screening of binding and inhibition assays of virus–receptor interactions. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.