4Q6U:
reference: Mycobacterium tuberculosis Rv3651 is a triple sensor-domain protein., Abendroth J, Frando A, Phan IQ, Staker BL, Myler PJ, Edwards TE, Grundner C, Protein Sci. 2018 Feb;27(2):568-572. doi: 10.1002/pro.3343. Epub 2017 Dec 5. PMID: 29119630

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