5H0I:
reference: Engineering a Catalytically Efficient Recombinant Protein Ligase., Yang R, Wong YH, Nguyen GK, Tam JP, Lescar J, Wu B, J Am Chem Soc. 2017 Mar 1. doi: 10.1021/jacs.6b12637. PMID: 28199119

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