5B6O:
reference: SARS-CoV 3CL protease cleaves its C-terminal autoprocessing site by novel subsite cooperativity., Muramatsu T, Takemoto C, Kim YT, Wang H, Nishii W, Terada T, Shirouzu M, Yokoyama S, Proc Natl Acad Sci U S A. 2016 Nov 15;113(46):12997-13002. Epub 2016 Oct 31. PMID: 27799534

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