4QH6:
reference: Molecular Design, Synthesis and Trypanocidal Activity of Dipeptidyl Nitriles as Cruzain Inhibitors., Avelar LA, Camilo CD, de Albuquerque S, Fernandes WB, Goncalez C, Kenny PW, Leitao A, McKerrow JH, Montanari CA, Orozco EV, Ribeiro JF, Rocha JR, Rosini F, Saidel ME, PLoS Negl Trop Dis. 2015 Jul 14;9(7):e0003916. doi: 10.1371/journal.pntd.0003916., eCollection 2015 Jul. PMID: 26173110

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