3FSV:
reference: Metal-binding loop length and not sequence dictates structure., Sato K, Li C, Salard I, Thompson AJ, Banfield MJ, Dennison C, Proc Natl Acad Sci U S A. 2009 Apr 7;106(14):5616-21. Epub 2009 Mar 19. PMID: 19299503

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