1CPX:
reference: Native carboxypeptidase A in a new crystal environment reveals a different conformation of the important tyrosine 248., Bukrinsky JT, Bjerrum MJ, Kadziola A, Biochemistry 1998 Nov 24;37(47):16555-64. PMID: 9843422

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