2JQS:
reference: Probing the conformation and dynamics of allatostatin neuropeptides: a structural model for functional differences., Banerjee M, Meyerowitz E, Huang C, Mohanty S, Peptides. 2008 Mar;29(3):375-85. Epub 2007 Nov 29. PMID: 18191874

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