4KY0:
reference: Crystal structure of a substrate-free aspartate transporter., Jensen S, Guskov A, Rempel S, Hanelt I, Slotboom DJ, Nat Struct Mol Biol. 2013 Oct;20(10):1224-6. doi: 10.1038/nsmb.2663. Epub 2013, Sep 8. PMID: 24013209

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