5LSR:
reference: Crystal structures of beta-carboxysome shell protein CcmP: ligand binding correlates with the closed or open central pore., Larsson AM, Hasse D, Valegard K, Andersson I, J Exp Bot. 2017 Mar 28. doi: 10.1093/jxb/erx070. PMID: 28369612

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