1CRG:
reference: The role of a conserved internal water molecule and its associated hydrogen bond network in cytochrome c., Berghuis AM, Guillemette JG, McLendon G, Sherman F, Smith M, Brayer GD, J Mol Biol 1994 Feb 25;236(3):786-99. PMID: 8114094

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