4POG:
reference: A conserved MCM single-stranded DNA binding element is essential for replication initiation., Froelich CA, Kang S, Epling LB, Bell SP, Enemark EJ, Elife. 2014 Apr 1;3:e01993. doi: 10.7554/eLife.01993. PMID: 24692448

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