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J Am Chem Soc. 2016 Apr 13;138(14):4807-17. doi: 10.1021/jacs.6b00092. Epub 2016 Apr 5.

Turning On and Off Photoinduced Electron Transfer in Fluorescent Proteins by π-Stacking, Halide Binding, and Tyr145 Mutations.

Author information

1
Shemiakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow 117997, Russia.
2
Nizhny Novgorod State Medical Academy , Nizhny Novgorod 603005, Russia.
3
Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States.
4
Department of Chemistry, Boston University , Boston, Massachusetts 02215, United States.
5
Department of Chemistry, Rice University , Houston, Texas 77251-1892, United States.

Abstract

Photoinduced electron transfer in fluorescent proteins from the GFP family can be regarded either as an asset facilitating new applications or as a nuisance leading to the loss of optical output. Photooxidation commonly results in green-to-red photoconversion called oxidative redding. We discovered that yellow FPs do not undergo redding; however, the redding is restored upon halide binding. Calculations of the energetics of one-electron oxidation and possible electron transfer (ET) pathways suggested that excited-state ET proceeds through a hopping mechanism via Tyr145. In YFPs, the π-stacking of the chromophore with Tyr203 reduces its electron-donating ability, which can be restored by halide binding. Point mutations confirmed that Tyr145 is a key residue controlling ET. Substitution of Tyr145 by less-efficient electron acceptors resulted in highly photostable mutants. This strategy (i.e., calculation and disruption of ET pathways by mutations) may represent a new approach toward enhancing photostability of FPs.

PMID:
26999576
DOI:
10.1021/jacs.6b00092
[Indexed for MEDLINE]
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