1TTK:
reference: Omega-conotoxin CVID inhibits a pharmacologically distinct voltage-sensitive calcium channel associated with transmitter release from preganglionic nerve terminals., Adams DJ, Smith AB, Schroeder CI, Yasuda T, Lewis RJ, J Biol Chem 2003 Feb 7;278(6):4057-62. Epub 2002 Nov 18. PMID: 12441339

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