| 4IC1: reference: Toroidal structure and DNA cleavage by the CRISPR-associated [4Fe-4S] cluster containing Cas4 nuclease SSO0001 from Sulfolobus solfataricus., Lemak S, Beloglazova N, Nocek B, Skarina T, Flick R, Brown G, Popovic A, Joachimiak A, Savchenko A, Yakunin AF, J Am Chem Soc. 2013 Nov 20;135(46):17476-87. doi: 10.1021/ja408729b. Epub 2013, Nov 11. PMID: 24171432 |
This OCA 
Structure page
uses Jmol,
developed by the Jmol Development Team
(documentation).