2MSQ:
reference: Transforming conotoxins into cyclotides: Backbone cyclization of P-superfamily conotoxins., Akcan M, Clark RJ, Daly NL, Conibear AC, de Faoite A, Heghinian MD, Sahil T, Adams DJ, Mari F, Craik DJ, Biopolymers. 2015 Jul 14. doi: 10.1002/bip.22699. PMID: 26172377

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