1YAL:
reference: Structure of chymopapain at 1.7 A resolution., Maes D, Bouckaert J, Poortmans F, Wyns L, Looze Y, Biochemistry 1996 Dec 17;35(50):16292-8. PMID: 8973203

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