1A3X:
reference: The allosteric regulation of pyruvate kinase by fructose-1,6-bisphosphate., Jurica MS, Mesecar A, Heath PJ, Shi W, Nowak T, Stoddard BL, Structure 1998 Feb 15;6(2):195-210. PMID: 9519410

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