2GOK:
reference: X-ray structure of imidazolonepropionase from Agrobacterium tumefaciens at 1.87 A resolution., Tyagi R, Kumaran D, Burley SK, Swaminathan S, Proteins. 2007 Nov 15;69(3):652-8. PMID: 17640072

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