3K6N:
reference: Physical determinants of strong voltage sensitivity of K(+) channel block., Xu Y, Shin HG, Szep S, Lu Z, Nat Struct Mol Biol. 2009 Dec;16(12):1252-8. Epub 2009 Nov 15. PMID: 19915587

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