4JQN:
reference: Blind Prediction of Charged Ligand Binding Affinities in a Model Binding Site., Rocklin GJ, Boyce SE, Fischer M, Fish I, Mobley DL, Shoichet BK, Dill KA, J Mol Biol. 2013 Jul 26. pii: S0022-2836(13)00477-4. doi:, 10.1016/j.jmb.2013.07.030. PMID: 23896298

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