4LLH:
reference: Substrate-bound outward-open state of the betaine transporter BetP provides insights into Na(+) coupling., Perez C, Faust B, Mehdipour AR, Francesconi KA, Forrest LR, Ziegler C, Nat Commun. 2014 Jul 15;5:4231. doi: 10.1038/ncomms5231. PMID: 25023443

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