4MWJ:
reference: Characterization of two distinct neuraminidases from avian-origin human-infecting H7N9 influenza viruses., Wu Y, Bi Y, Vavricka CJ, Sun X, Zhang Y, Gao F, Zhao M, Xiao H, Qin C, He J, Liu W, Yan J, Qi J, Gao GF, Cell Res. 2013 Oct 29. doi: 10.1038/cr.2013.144. PMID: 24165891

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