title: Second sialic acid binding site in Newcastle disease virus hemagglutinin-neuraminidase: implications for fusion.
abstract: Paramyxoviruses are the leading cause of respiratory disease in children. Several paramyxoviruses possess a surface glycoprotein, the hemagglutinin-neuraminidase (HN), that is involved in attachment to sialic acid receptors, promotion of fusion, and removal of sialic acid from infected cells and progeny virions. Previously we showed that Newcastle disease virus (NDV) HN contained a pliable sialic acid recognition site that could take two states, a binding state and a catalytic state. Here we present evidence for a second sialic acid binding site at the dimer interface of HN and present a model for its involvement in cell fusion. Three different crystal forms of NDV HN now reveal identical tetrameric arrangements of HN monomers, perhaps indicative of the tetramer association found on the viral surface.
authors.affiliation: Centre for Biomolecular Sciences, University of St. Andrews, St. Andrews, Fife KY16 9ST, United Kingdom.
authors.forename: Viatcheslav
authors.initials: V
authors.lastname: Zaitsev
authors.forename: Mark
authors.initials: M
authors.lastname: von Itzstein
authors.forename: Darrin
authors.initials: D
authors.lastname: Groves
authors.forename: Milton
authors.initials: M
authors.lastname: Kiefel
authors.forename: Toru
authors.initials: T
authors.lastname: Takimoto
authors.forename: Allen
authors.initials: A
authors.lastname: Portner
authors.forename: Garry
authors.initials: G
authors.lastname: Taylor
mesh_terms: D001665:Binding Sites; D002459:Cell Fusion; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D015707:HN Protein / Q000737:chemistry* / Q000378:metabolism*; D008561:Membrane Fusion; D008954:Models, Biological; D008958:Models, Molecular; D009522:Newcastle disease virus / Q000737:chemistry* / Q000378:metabolism; D020836:Protein Structure, Quaternary; D012794:Sialic Acids / Q000378:metabolism*
chemical_list: D015707:HN Protein; D012794:Sialic Acids