1JQG:
reference: Crystal structure of a novel mid-gut procarboxypeptidase from the cotton pest Helicoverpa armigera., Estebanez-Perpina E, Bayes A, Vendrell J, Jongsma MA, Bown DP, Gatehouse JA, Huber R, Bode W, Aviles FX, Reverter D, J Mol Biol 2001 Oct 26;313(3):629-38. PMID: 11676544

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