2DCH:
reference: Structure of a hyperthermophilic archaeal homing endonuclease, I-Tsp061I: contribution of cross-domain polar networks to thermostability., Nakayama H, Shimamura T, Imagawa T, Shirai N, Itoh T, Sako Y, Miyano M, Sakuraba H, Ohshima T, Nomura N, Tsuge H, J Mol Biol. 2007 Jan 12;365(2):362-78. Epub 2006 Sep 29. PMID: 17069851

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