1CI7:
reference: The structural mechanism for half-the-sites reactivity in an enzyme, thymidylate synthase, involves a relay of changes between subunits., Anderson AC, O'Neil RH, DeLano WL, Stroud RM, Biochemistry 1999 Oct 19;38(42):13829-36. PMID: 10529228

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