1JQP: Dipeptidyl Peptidase I (Cathepsin C), A Tetrameric Cysteine Of The Papain Family
reference: Tetrameric dipeptidyl peptidase I directs substrate specificity by use of the residual pro-part domain., Olsen JG, Kadziola A, Lauritzen C, Pedersen J, Larsen S, Dahl SW, FEBS Lett 2001 Oct 12;506(3):201-6. PMID: 11602245

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