This research reveals the phylogenetic history and structural information of the hemagglutinin（HA） and neuraminidase（NA） from novel avian influenza virus A/Hangzhou/1/2013（HTN9_2013） strain from human infected in China. Strains closely related to the HTN9 2013 strain were obtained from Nation Center for Biotechnology Information（USA）-basic local alignment search tool（NCBI-BLAST） searching, and the phylogenetic trees were con- structed. The 3D structures of HA and NA from H7N9 2013 strain were built by homology modeling technology, and molecular dynamics（MD） simulations were performed on the high-performance computer cluster. Characteristic amino acid sites were then screened from multiple sequence alignment（MSA） via home-made Python script and mapped onto the 3D structures. The thermodynamic characteristic root-mean-square-fluctuation （RMSF） of these sites in the structure was also analyzed with MD trajectories. The HA of HTN9_2013 strain is closely related to the A/duck/Zhejiang/12/2011 strain isolated in China, while the NA of HTN9 2013 strain is mostly related to the A/mallard/Czech Republic/13438-29K/2010 strain isolated in Europe. The 3D structures of HA and NA from H7N9 2013 stain are mostly identical to the existing structure of H7 and N9. A total of 11 and 14 characteristic ami- no acid sites were identified in HA and NA, respectively, in HTN9_2013. Structural analysis indicates that certain sites in the top region of HA are important, at which the mutation of some amino acids can impact the receptor bin- ding that may be related to its infection of human beings.
