4IJG:
reference: Origins of Fluorescence in Evolved Bacteriophytochromes., Bhattacharya S, Auldridge ME, Lehtivuori H, Ihalainen JA, Forest KT, J Biol Chem. 2014 Sep 24. pii: jbc.M114.589739. PMID: 25253687

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