4ZYL:
reference: Structure of the response regulator RPA3017 involved in red-light signaling in Rhodopseudomonas palustris., Yang X, Zeng X, Moffat K, Yang X, Acta Crystallogr F Struct Biol Commun. 2015 Oct;71(Pt 10):1215-22. doi:, 10.1107/S2053230X15014661. Epub 2015 Sep 23. PMID: 26457509

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