1ELF:
reference: Nature of the inactivation of elastase by N-peptidyl-O-aroyl hydroxylamine as a function of pH., Ding X, Rasmussen BF, Demuth HU, Ringe D, Steinmetz AC, Biochemistry 1995 Jun 13;34(23):7749-56. PMID: 7779821

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