1UIV:
reference: Crystal structures of the liganded and unliganded nickel-binding protein NikA from Escherichia coli., Heddle J, Scott DJ, Unzai S, Park SY, Tame JR, J Biol Chem 2003 Dec 12;278(50):50322-9. Epub 2003 Sep 5. PMID: 12960164

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