5LU7:
reference: A half-site multimeric enzyme achieves its cooperativity without conformational changes., Vivoli M, Pang J, Harmer NJ, Sci Rep. 2017 Nov 28;7(1):16529. doi: 10.1038/s41598-017-16421-2. PMID: 29184087

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