1RUY:
reference: The structure and receptor binding properties of the 1918 influenza hemagglutinin., Gamblin SJ, Haire LF, Russell RJ, Stevens DJ, Xiao B, Ha Y, Vasisht N, Steinhauer DA, Daniels RS, Elliot A, Wiley DC, Skehel JJ, Science 2004 Mar 19;303(5665):1838-42. Epub 2004 Feb 5. PMID: 14764886

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