5GWY:
reference: Structure of Main Protease from Human Coronavirus NL63: Insights for Wide Spectrum Anti-Coronavirus Drug Design., Wang F, Chen C, Tan W, Yang K, Yang H, Sci Rep. 2016 Mar 7;6:22677. doi: 10.1038/srep22677. PMID: 26948040

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