4YWG:
reference: The V1V2 Region of HIV-1 gp120 Forms a Five-Stranded Beta Barrel., Pan R, Gorny MK, Zolla-Pazner S, Kong XP, J Virol. 2015 Aug 1;89(15):8003-10. doi: 10.1128/JVI.00754-15. Epub 2015 May 27. PMID: 26018158

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