6MB4:
reference: Encoding of Promiscuity in an Aminoglycoside Acetyltransferase., Kumar P, Selvaraj B, Serpersu EH, Cuneo MJ, J Med Chem. 2018 Oct 31. doi: 10.1021/acs.jmedchem.8b01393. PMID: 30347146

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