4HHX:
reference: Structure of the cytoplasmic domain of TcpE, the inner membrane core protein required for assembly of the Vibrio cholerae toxin-coregulated pilus., Kolappan S, Craig L, Acta Crystallogr D Biol Crystallogr. 2013 Apr;69(Pt 4):513-9. doi:, 10.1107/S0907444912050330. Epub 2013 Mar 9. PMID: 23519659

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