Deactivation Pathways of an Isolated Green Fluorescent Protein Model Chromophore Studied by Electronic Action Spectroscopy
- 11 November 2009
- journal article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 131 (47), 17038-17039
- https://doi.org/10.1021/ja9066404
Abstract
The mechanism of fluorescence and fluorescence quenching of the green fluorescent protein (GFP) is not well-understood. To gain insight into the effect of the surrounding protein on the chromophore buried at its center, the intrinsic electronic absorption and deactivation pathways of a gaseous model chromophore, p-hydroxybenzylidene-2,3-dimethylimidazolone (HBDI) were investigated. No fluorescence from photoactivated gaseous HBDI− was detected in the range 480−1100 nm, in line with the ultrafast rate of internal conversion of HBDI− in solution. Two different gas-phase deactivation pathways were found: photofragmentation and electron photodetachment. Electronic action spectra for each deactivation pathway were constructed by monitoring the disappearance of HBDI− and appearance of product ions as a function of excitation wavelength. The action spectra measured for each pathway are distinct, with electron photodetachment being strongly favored at higher photon energies. The combined (total) gas-phase action spectrum has a band origin at 482.5 nm (23340 cm−1) and covers a broad spectral range, 390−510 nm. This extended gas-phase action spectrum exhibits vibronic activity that matches well with the results of previous cold condensed-phase experiments and high-level in vacuo computations, with features evident at +550, +1500, and +2800 cm−1 with respect to the band origin.Keywords
This publication has 24 references indexed in Scilit:
- Absorption Spectrum of the Green Fluorescent Protein Chromophore AnionIn VacuoPhysical Review Letters, 2001
- Electronic Structure of the Chromophore in Green Fluorescent Protein (GFP)Journal of the American Chemical Society, 1998
- Fluorescent properties of model chromophores of tyrosine-66 substituted mutants of Aequorea green fluorescent protein (GEP)Tetrahedron Letters, 1998
- THE GREEN FLUORESCENT PROTEINAnnual Review of Biochemistry, 1998
- Use of the green fluorescent protein and its mutants in quantitative fluorescence microscopyBiophysical Journal, 1997
- Chemical nature of the light emitter of the Aequorea green fluorescent proteinProceedings of the National Academy of Sciences, 1996
- The molecular structure of green fluorescent proteinNature Biotechnology, 1996
- Ultra-fast excited state dynamics in green fluorescent protein: multiple states and proton transfer.Proceedings of the National Academy of Sciences, 1996
- Wavelength mutations and posttranslational autoxidation of green fluorescent protein.Proceedings of the National Academy of Sciences, 1994
- Chemical structure of the hexapeptide chromophore of the Aequorea green-fluorescent proteinBiochemistry, 1993