1NKD:
reference: Structural parameters for proteins derived from the atomic resolution (1.09 A) structure of a designed variant of the ColE1 ROP protein., Vlassi M, Dauter Z, Wilson KS, Kokkinidis M, Acta Crystallogr D Biol Crystallogr 1998 Nov 1;54(Pt 6 Pt 2):1245-60. PMID: 10089502

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