4J90:
reference: The structure of the KtrAB potassium transporter., Vieira-Pires RS, Szollosi A, Morais-Cabral JH, Nature. 2013 Apr 18;496(7445):323-8. doi: 10.1038/nature12055. PMID: 23598340

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