6C8X:
reference: Sub-picomolar Inhibition of HIV-1 Protease with a Boronic Acid., Windsor IW, Palte MJ, Lukesh JC 3rd, Gold B, Forest KT, Raines RT, J Am Chem Soc. 2018 Oct 31;140(43):14015-14018. doi: 10.1021/jacs.8b07366. Epub, 2018 Oct 22. PMID: 30346745

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