1ORO:
reference: A flexible loop at the dimer interface is a part of the active site of the adjacent monomer of Escherichia coli orotate phosphoribosyltransferase., Henriksen A, Aghajari N, Jensen KF, Gajhede M, Biochemistry 1996 Mar 26;35(12):3803-9. PMID: 8620002

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