4WY9:
reference: The Crystal Structure of the Tandem-PAS Sensing Domain of Campylobacter jejuni Chemoreceptor Tlp1 Suggests Indirect Mechanism of Ligand Recognition., Machuca MA, Liu YC, Beckham SA, Gunzburg MJ, Roujeinikova A, J Struct Biol. 2016 Feb 23. pii: S1047-8477(16)30034-X. doi:, 10.1016/j.jsb.2016.02.019. PMID: 26923153

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