4DXB:
reference: Structure of an Engineered beta-Lactamase Maltose Binding Protein Fusion Protein: Insights into Heterotropic Allosteric Regulation., Ke W, Laurent AH, Armstrong MD, Chen Y, Smith WE, Liang J, Wright CM, Ostermeier M, van den Akker F, PLoS One. 2012;7(6):e39168. Epub 2012 Jun 14. PMID: 22720063

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