5BK4:
reference: Cryo-EM structure of Mcm2-7 double hexamer on DNA suggests a lagging-strand DNA extrusion model., Noguchi Y, Yuan Z, Bai L, Schneider S, Zhao G, Stillman B, Speck C, Li H, Proc Natl Acad Sci U S A. 2017 Oct 25. pii: 201712537. doi:, 10.1073/pnas.1712537114. PMID: 29078375

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