2XE4:
reference: Crystal structure of Leishmania major oligopeptidase B gives insight into the enzymatic properties of a trypanosomatid virulence factor., McLuskey K, Paterson NG, Bland ND, Isaacs NW, Mottram JC, J Biol Chem. 2010 Dec 10;285(50):39249-59. Epub 2010 Oct 5. PMID: 20926390

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