3E5W:
reference: Trans-cis isomerization is responsible for the red-shifted fluorescence in variants of the red fluorescent protein eqFP611., Nienhaus K, Nar H, Heilker R, Wiedenmann J, Nienhaus GU, J Am Chem Soc. 2008 Sep 24;130(38):12578-9. Epub 2008 Aug 30. PMID: 18761441

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