Structural Characterization of the Hemagglutinin Receptor Specificity from the 2009 H1N1 Influenza Pandemic.
Xu, R., McBride, R., Nycholat, C.M., Paulson, J.C., Wilson, I.A.(2012) J Virol 86: 982-990
- PubMed: 22072785 
- DOI: https://doi.org/10.1128/JVI.06322-11
- Primary Citation of Related Structures:  
3UBE, 3UBJ, 3UBN, 3UBQ - PubMed Abstract: 
Influenza virus hemagglutinin (HA) is the viral envelope protein that mediates viral attachment to host cells and elicits membrane fusion. The HA receptor-binding specificity is a key determinant for the host range and transmissibility of influenza viruses. In human pandemics of the 20th century, the HA normally has acquired specificity for human-like receptors before widespread infection. Crystal structures of the H1 HA from the 2009 human pandemic (A/California/04/2009 [CA04]) in complex with human and avian receptor analogs reveal conserved recognition of the terminal sialic acid of the glycan ligands. However, favorable interactions beyond the sialic acid are found only for ¦Á2-6-linked glycans and are mediated by Asp190 and Asp225, which hydrogen bond with Gal-2 and GlcNAc-3. For ¦Á2-3-linked glycan receptors, no specific interactions beyond the terminal sialic acid are observed. Our structural and glycan microarray analyses, in the context of other high-resolution HA structures with ¦Á2-6- and ¦Á2-3-linked glycans, now elucidate the structural basis of receptor-binding specificity for H1 HAs in human and avian viruses and provide a structural explanation for the preference for ¦Á2-6 siaylated glycan receptors for the 2009 pandemic swine flu virus.
Organizational Affiliation: 
Department of Molecular Biology and Department of Chemical Physiology, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.