4ZIR:
reference: ATP binding drives substrate capture in an ECF transporter by a release-and-catch mechanism., Karpowich NK, Song JM, Cocco N, Wang DN, Nat Struct Mol Biol. 2015 Jun 8. doi: 10.1038/nsmb.3040. PMID: 26052893

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