4BJR:
reference: Crystal Structure of the Complex between Prokaryotic Ubiquitin-like Protein and Its Ligase PafA., Barandun J, Delley CL, Ban N, Weber-Ban E, J Am Chem Soc. 2013 Apr 23. PMID: 23601177

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