5HM4:
reference: Periplasmic Binding Protein Dimer Has a Second Allosteric Event Tied to Ligand Binding., Li L, Ghimire-Rijal S, Lucas SL, Stanley CB, Wright E, Agarwal PK, Myles DA, Cuneo MJ, Biochemistry. 2017 Oct 10;56(40):5328-5337. doi: 10.1021/acs.biochem.7b00657., Epub 2017 Sep 22. PMID: 28876049

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