1.
Phys Chem Chem Phys
; 18(38): 26703-26711, 2016 Sep 29.
Article
in English
| MEDLINE
| ID: mdl-27711376
ABSTRACT
We report the synthesis and characterization of a pH-sensitive fluorescence switch based on a conformationally-locked green fluorescent protein (GFP) chromophore. The chromophore differs from difluoroboryl-locked parent by the addition of a titratable alcohol group on the imidazolinone ring. The chromophore is fluorescent at pH ≤ 5, but becomes non-fluorescent at higher pH, where the substituent is ionized. We use a quantum chemical model to show that the mechanism of the fluorescence turn-off is electronically analogous to photochemical meta effects in aryl-containing systems.