3UIQ:
reference: Bidentate and tridentate metal-ion coordination states within ternary complexes of RB69 DNA polymerase., Xia S, Eom SH, Konigsberg WH, Wang J, Protein Sci. 2012 Mar;21(3):447-51. doi: 10.1002/pro.2026. Epub 2012 Jan 31. PMID: 22238207

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