title: Amino acid determinants conferring stable sialidase activity at low pH for H5N1 influenza A virus neuraminidase.
abstract: Avian influenza A viruses (IAVs) and human 1918, 1957, and 1968 pandemic IAVs all have neuraminidases (NAs) that are stable at low pH sialidase activity, yet most human epidemic IAVs do not. We examined the pH stability of H5N1 highly pathogenic avian IAV (HPAI) NAs and identified amino acids responsible for conferring stability at low pH. We found that, unlike other avian viruses, most H5N1 IAVs isolated since 2003 had NAs that were unstable at low pH, similar to human epidemic IAVs. These H5N1 viruses are thus already human virus-like and, therefore, have the frequent infections of humans.
authors: Influenza Research Institute, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA ; Department of Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, and Global COE Program for Innovation in Human Health Sciences, Japan.
authors: Tadanobu
authors: T
authors: Takahashi
authors: Chairul A
authors: CA
authors: Nidom
authors: Mai Thi
authors: MT
authors: Quynh Le
authors: Takashi
authors: T
authors: Suzuki
authors: Yoshihiro
authors: Y
authors: Kawaoka
keywords: Avian influenza A virus; FBS, fetal bovine serum; H5N1; HA, hemagglutinin; HPAI, highly pathogenic avian influenza A virus; Highly pathogenic; IAV, influenza A virus; Low-pH stability; NA, neuraminidase; Neuraminidase; PBS, phosphate-buffered saline; Sialidase; TGF-β, transforming growth factor-beta
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