Chemically Modulating the Photophysics of the GFP Chromophore

There is growing interest in engineering the properties of fluorescent proteins through modifications to the chromophore structure utilizing mutagenesis with either natural or unnatural amino acids. This entails an understanding of the photophysical and photochemical properties of the modified chrom...

Full description

Saved in:
Bibliographic Details
Published in:The journal of physical chemistry. B Vol. 115; no. 6; pp. 1571 - 1577
Main Authors: Conyard, Jamie, Kondo, Minako, Heisler, Ismael A, Jones, Garth, Baldridge, Anthony, Tolbert, Laren M, Solntsev, Kyril M, Meech, Stephen R
Format: Journal Article
Language:English
Published: United States American Chemical Society 17-02-2011
Subjects:
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:There is growing interest in engineering the properties of fluorescent proteins through modifications to the chromophore structure utilizing mutagenesis with either natural or unnatural amino acids. This entails an understanding of the photophysical and photochemical properties of the modified chromophore. In this work, a range of GFP chromophores with different alkyl substituents are synthesized and their electronic spectra, pH dependence, and ultrafast fluorescence decay kinetics are investigated. The weakly electron donating character of the alkyl substituents leads to dramatic red shifts in the electronic spectra of the anions, which are accompanied by increased fluorescence decay times. This high sensitivity of electronic structure to substitution is also characteristic of some fluorescent proteins. The solvent viscosity dependence of the decay kinetics are investigated, and found to be consistent with a bimodal radiationless relaxation coordinate. Some substituents are shown to distort the planar structure of the chromophore, which results in a blue shift in the electronic spectra and a strong enhancement of the radiationless decay. The significance of these data for the rational design of novel fluorescent proteins is discussed.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp111593x