5KO3:
reference: X-ray Structure and Enzymatic Activity Profile of a Core Papain-like Protease of MERS Coronavirus with utility for structure-based drug design., Clasman JR, Baez-Santos YM, Mettelman RC, O'Brien A, Baker SC, Mesecar AD, Sci Rep. 2017 Jan 12;7:40292. doi: 10.1038/srep40292. PMID: 28079137

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