Structural basis for bathochromic shift of fluorescence in far-red fluorescent proteins eqFP650 and eqFP670

The crystal structures of the far-red fluorescent proteins eqFP650 and eqFP670 have been solved at 1.8 and 1.6 Å resolution, respectively. This permitted identification of the structural elements responsible for the bathochromic shift in both considered far-red fluorescent proteins.