Ma, Jianpeng2013-03-082013-03-082011Ni, Fengyun. "Role of Phe95 In the Receptor Binding of Influenza B Virus Hemagglutinin." (2011) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/70372">https://hdl.handle.net/1911/70372</a>.https://hdl.handle.net/1911/70372Influenza A and B viruses are significant human pathogens responsible for the annual seasonal "flu". Diverged some 2000 years ago, influenza B virus has several important differences from influenza A virus, including lower receptor-binding affinity and very limited host range. Based on sequence comparison and our prior structural studies, we hypothesized that a key difference in the receptor-binding site of influenza virus hemagglutinin (HA), phenylalaline (Phe) 95 in influenza B virus HA (BHA), versus tyrosine (Tyr) in influenza A virus HA (AHA), is possibly the molecular basis for the different receptor-binding affinity. We further hypothesized that this could be at least partially responsible for the very limited host range of influenza B virus. By using glycan and red blood cell binding assays, we demonstrated that the mutation Phe95[arrow right]Tyr in BHA substantially enhanced receptor-binding affinity. Furthermore, this mutation efficiently competed against the infection of influenza A virus and greatly improved the binding of BHA to three mammalian cell lines. Taken together, residue 95 of BHA appears to be a key determinant for the receptor binding affinity and host range of influenza B virus.27 p.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Pure sciencesBiochemistryThesisNiFTHESIS PHYS. 2011 NI