1CTX:
reference: Three-dimensional structure of the "long" neurotoxin from cobra venom., Walkinshaw MD, Saenger W, Maelicke A, Proc Natl Acad Sci U S A 1980 May;77(5):2400-4. PMID: 6930640

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