3LF3:
reference: Understanding blue-to-red conversion in monomeric fluorescent timers and hydrolytic degradation of their chromophores., Pletnev S, Subach FV, Dauter Z, Wlodawer A, Verkhusha VV, J Am Chem Soc. 2010 Feb 24;132(7):2243-53. PMID: 20121102

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