2K1X:
reference: Solution Structure and Calcium-Binding Properties of M-Crystallin, A Primordial betagamma-Crystallin from Archaea., Barnwal RP, Jobby MK, Devi KM, Sharma Y, Chary KV, J Mol Biol. 2008 Dec 31. PMID: 19138688

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