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

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• 作者：Alexey M. Bogdanov ; Atanu Acharya ; Anastasia V. Titelmayer ; Anastasia V. Mamontova ; Ksenia B. Bravaya ; Anatoly B. Kolomeisky ; Konstantin A. Lukyanov ; Anna I. Krylov
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：April 13, 2016
• 年：2016
• 卷：138
• 期：14
• 页码：4807-4817
• 全文大小：664K
• 年卷期：0
• ISSN：1520-5126

文摘

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.