4C2U:
reference: Structural and Mechanistic Insight into DNA Unwinding by Deinococcus radiodurans UvrD., Stelter M, Acajjaoui S, McSweeney S, Timmins J, PLoS One. 2013 Oct 15;8(10):e77364. doi: 10.1371/journal.pone.0077364. PMID: 24143224

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