3KDK:
reference: Structure of the endonuclease domain of MutL: unlicensed to cut., Pillon MC, Lorenowicz JJ, Uckelmann M, Klocko AD, Mitchell RR, Chung YS, Modrich P, Walker GC, Simmons LA, Friedhoff P, Guarne A, Mol Cell. 2010 Jul 9;39(1):145-51. PMID: 20603082

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