Reverse pH-dependence of chromophore protonation explains the large Stokes shift of the red fluorescent protein mKeima.
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.
Violot
Sebastien
S
Institut de Recherches en Technologies et Sciences pour le Vivant, Laboratoire de Physiologie Cellulaire Végétale, CEA, CNRS, INRA, Université Joseph Fourier, 17 rue des Martyrs, F-38054 Grenoble, France.
Carpentier
Philippe
P
Blanchoin
Laurent
L
Bourgeois
Dominique
D
D000042:Absorption; D018360:Crystallography, X-Ray; D004583:Electrons; D006863:Hydrogen-Ion Concentration; D008164:Luminescent Proteins / Q000737:chemistry*; D011522:Protons; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman; D013237:Stereoisomerism; D000097573:Red Fluorescent Protein
D008164:Luminescent Proteins; D011522:Protons; D000097573:Red Fluorescent Protein