title: A molecular mechanism for the low-pH stability of sialidase activity of influenza A virus N2 neuraminidases.
abstract: Four human pandemic influenza A virus strains isolated in 1957 and 1968, but not most of the epidemic strains isolated after 1968, possess sialidase activity under low-pH conditions. Here, we used cell-expressed neuraminidases (NAs) to determine the region of the N2 NA that is associated with low-pH stability of sialidase activity. We found that consensus amino acid regions responsible for low-pH stability did not exist in pandemic NAs but that two amino acid substitutions in the low-pH-stable A/Hong Kong/1/68 (H3N2) NA and a single substitution in the low-pH-unstable A/Texas/68 (H2N2) NA resulted in significant change in low-pH stability.
authors.affiliation: Department of Biochemistry, University of Shizuoka, School of Pharmaceutical Sciences, CREST, JST, and COE Program in the 21st Century, 422-8526, Shizuoka, Japan.
authors.forename: Tadanobu
authors.initials: T
authors.lastname: Takahashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Suzuki
authors.forename: Kazuya I-P Jwa
authors.initials: KI
authors.lastname: Hidari
authors.forename: Daisei
authors.initials: D
authors.lastname: Miyamoto
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Suzuki
mesh_terms: D019943:Amino Acid Substitution; D000596:Amino Acids / Q000032:analysis; D001483:Base Sequence; D002460:Cell Line; D004795:Enzyme Stability; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009980:Influenza A virus / Q000201:enzymology*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009439:Neuraminidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D000596:Amino Acids; D011993:Recombinant Fusion Proteins; D009439:Neuraminidase