2PSG:
reference: Refined structure of porcine pepsinogen at 1.8 A resolution., Sielecki AR, Fujinaga M, Read RJ, James MN, J Mol Biol 1991 Jun 20;219(4):671-92. PMID: 2056534

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