4GYS:
reference: The Structure of Allophanate Hydrolase from Granulibacter bethesdensis Provides Insights into Substrate Specificity in the Amidase Signature Family., Lin Y, St Maurice M, Biochemistry. 2013 Jan 29;52(4):690-700. doi: 10.1021/bi301242m. Epub 2013 Jan, 18. PMID: 23282241

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