Reverse pH-dependence of chromophore protonation explains the large stokes shift of the red fluorescent protein mKeima.

Sebastien Violot (1) , Philippe Carpentier (2) , Laurent Blanchoin (1) , Dominique Bourgeois (2, 3)

1 LPCV - Laboratoire de physiologie cellulaire végétale
2 IBS - UMR 5075 - Institut de biologie structurale
3 ESRF - European Synchrotron Radiation Facility

The recently developed red fluorescent protein Keima exhibits the largest Stokes shift (180 nm) observed to date. Combining X-ray crystallography with (in crystallo) UV-visible absorption, fluorescence, and Raman spectroscopy, we have investigated molecular determinants of this peculiar property. The results demonstrate a pH-dependent "reverse chromophore protonation" triggered by the key residue Asp157 and which couples to cis/trans isomerization of the chromophore. These data provided guidelines to rationally design a useful Keima variant.

Mots clés: technique; imaging; fluorescence; red fluorescent protein; fluorophore

Domaines: Biologie cellulaire

Sebastien Violot, Philippe Carpentier, Laurent Blanchoin, Dominique Bourgeois. Reverse pH-dependence of chromophore protonation explains the large stokes shift of the red fluorescent protein mKeima.. Journal of the American Chemical Society, 2009, 131 (30), pp.10356-7. ⟨10.1021/ja903695n⟩. ⟨hal-00424231⟩