Synthetic Green Fluorescent Protein Chromophores

GFP is widely used as a
biological marker because of its superb fluorescence
properties. We have synthesized GFP chromophore and
its derivatives, and their photochemistry
and photophysics were investigated using various
steady-state and time-resolved techniques.
We first compared their optical properties between
solution and solid state. We found some O-alkyl
GFP chromophore derivatives exhibit large
fluorescent enhancement in the solid state.
Cis/trans isomerization is thought to be responsible
for blinking behavior in fluorescent protein;
however, the mechanism of the thermal reverse
isomerization is more problematic. Using
Hammett plot studies, we conceived,
for the first time, a novel nucleophilic
addition/elimination mechanism.
Finally, a hydroxyl substituent at the meta position
shows enhanced charge transfer and greater acidity
in the excited state. As a result, we have
demonstrated that the fast quenching of the excited
state by internal conversion to the ground state is
much slower in meta- than in para-HOBDI derivatives.
This allows studies of this ultrafast intermolecular
ESPT that competes with isomerization.

Autorentext

Jian Dong obtained his Ph.D. in Organic Chemistry from Georgia Institute of Technology in Auguest 2008. He is currently a Postdoctoral Appointee at US Argonne National Laboratory. His research interests are photochemical and photophysical studies of organic synthetic Green Fluorescent Protein (GFP) chromophore and its derivatives.

Klappentext

GFP is widely used as a biological marker because of its superb fluorescence properties. We have synthesized GFP chromophore and its derivatives, and their photochemistry and photophysics were investigated using various steady-state and time-resolved techniques. We first compared their optical properties between solution and solid state. We found some O-alkyl GFP chromophore derivatives exhibit large fluorescent enhancement in the solid state.Cis/trans isomerization is thought to be responsible for blinking behavior in fluorescent protein; however, the mechanism of the thermal reverse isomerization is more problematic. Using Hammett plot studies, we conceived, for the first time, a novel nucleophilic addition/elimination mechanism. Finally, a hydroxyl substituent at the meta position shows enhanced charge transfer and greater acidity in the excited state. As a result, we have demonstrated that the fast quenching of the excited state by internal conversion to the ground state is much slower in meta- than in para-HOBDI derivatives. This allows studies of this ultrafast intermolecular ESPT that competes with isomerization.