1AOL:
reference: Structure of a murine leukemia virus receptor-binding glycoprotein at 2.0 angstrom resolution., Fass D, Davey RA, Hamson CA, Kim PS, Cunningham JM, Berger JM, Science 1997 Sep 12;277(5332):1662-6. PMID: 9287219

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