4WEF:
reference: Catalytic mechanism and novel receptor binding sites of human parainfluenza virus type 3 hemagglutinin-neuraminidase (hPIV3 HN)., Streltsov VA, Pilling P, Barrett S, McKimm-Breschkin JL, Antiviral Res. 2015 Sep 10. pii: S0166-3542(15)00209-0. doi:, 10.1016/j.antiviral.2015.08.014. PMID: 26364554

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