1PSI:
reference: Inhibitory conformation of the reactive loop of alpha 1-antitrypsin., Elliott PR, Lomas DA, Carrell RW, Abrahams JP, Nat Struct Biol 1996 Aug;3(8):676-81. PMID: 8756325

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