4A5M:
reference: Structural insights into the redox-switch mechanism of the MarR/DUF24-type regulator HypR., Palm GJ, Khanh Chi B, Waack P, Gronau K, Becher D, Albrecht D, Hinrichs W, Read RJ, Antelmann H, Nucleic Acids Res. 2012 May 1;40(9):4178-92. Epub 2012 Jan 11. PMID: 22238377

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