2GCT:
reference: Structure of gamma-chymotrypsin in the range pH 2.0 to pH 10.5 suggests that gamma-chymotrypsin is a covalent acyl-enzyme adduct at low pH., Dixon MM, Brennan RG, Matthews BW, Int J Biol Macromol 1991 Apr;13(2):89-96. PMID: 1888717

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