2LKH:
reference: NMR structure and dynamics of water-solubilized transmembrane domains of nicotinic acetylcholine receptor., Cui T, Mowrey D, Bondarenko V, Tillman T, Ma D, Landrum E, Perez-Aguilar JM, He J, Wang W, Saven JG, Eckenhoff R, Tang P, Xu Y, Biochim Biophys Acta. 2011 Dec 3. PMID: 22155685

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