4ATV:
reference: Crystal structure of the sodium-proton antiporter NhaA dimer and new mechanistic insights., Lee C, Yashiro S, Dotson DL, Uzdavinys P, Iwata S, Sansom MS, von Ballmoos C, Beckstein O, Drew D, Cameron AD, J Gen Physiol. 2014 Dec;144(6):529-44. doi: 10.1085/jgp.201411219. PMID: 25422503

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