title: Influenza viral hemagglutinin complicated shape is advantageous to its binding affinity for sialosaccharide receptor.
abstract: Do the complexity and the bulkiness of a protein affect the affinity between protein and ligand? We attempted to investigate this problem by using ab initio fragment molecular orbital (FMO) method to calculate the binding energy between human influenza viral hemagglutinin (HA) and human oligo-saccharide receptor. We compared the binding energies of 4 different sizes of human A virus HA H3 subtype complexed with human receptor Neu5Ac(alpha2-6)Gal as a model. The full shape receptor binding domain complexed with Neu5Ac(alpha2-6)Gal had the highest binding energy 170.3kcal/mol at the FMO-HF/STO-3G level, which was 52.3kcal/mol higher than that of the smallest domain-receptor complex. These data provide the consideration of the backyard bulkiness beyond the binding site of protein to the protein-ligand stability.
authors.affiliation: Department of Applied Bioorganic Chemistry, The United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Sawada
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nakano
authors.forename: Tohru
authors.initials: T
authors.lastname: Suzuki
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kawaoka
authors.forename: Hideharu
authors.initials: H
authors.lastname: Ishida
authors.forename: Makoto
authors.initials: M
authors.lastname: Kiso
mesh_terms: D001665:Binding Sites; D002151:Calorimetry; D002240:Carbohydrate Sequence; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D009844:Oligosaccharides / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000502:physiology*
chemical_list: D019267:Hemagglutinin Glycoproteins, Influenza Virus; D009844:Oligosaccharides; D011956:Receptors, Cell Surface; C055213:saccharide-binding proteins