5VMG:
reference: Determinant of receptor-preference switch in influenza hemagglutinin., Ni F, Kondrashkina E, Wang Q, Virology. 2017 Oct 18;513:98-107. doi: 10.1016/j.virol.2017.10.010. PMID: 29055255

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).