4FHT:
reference: Study of PcaV from Streptomyces coelicolor yields new insights into ligand-responsive MarR family transcription factors., Davis JR, Brown BL, Page R, Sello JK, Nucleic Acids Res. 2013 Apr 1;41(6):3888-900. doi: 10.1093/nar/gkt009. Epub 2013 , Feb 8. PMID: 23396446

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