6UFE:
reference: The structure of a potassium-selective ion channel reveals a hydrophobic gate regulating ion permeation., Langan PS, Vandavasi VG, Kopec W, Sullivan B, Afonne PV, Weiss KL, de Groot BL, Coates L, IUCrJ. 2020 Jul 25;7(Pt 5):835-843. doi: 10.1107/S2052252520008271. eCollection, 2020 Sep 1. PMID: 32939275

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