2GPW:
reference: Is dimerization required for the catalytic activity of bacterial biotin carboxylase?, Shen Y, Chou CY, Chang GG, Tong L, Mol Cell. 2006 Jun 23;22(6):807-18. PMID: 16793549

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