A radical-triggered reaction mechanism of the green-to-red photoconversion of EosFP
| Autor: | Clyde Fare, Peter R. Rich, Jasper J. van Thor, Violeta Cordon-Preciado, Jasper J. Michels, Letong Yuan, Michael J. Bearpark |
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| Přispěvatelé: | Biotechnology and Biological Sciences Research Council, Engineering & Physical Science Research Council (EPSRC) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Reaction mechanism
02 Physical Sciences Chemistry Reaction intermediate Chromophore Photochemistry Chemical reaction 09 Engineering Surfaces Coatings and Films Photochromism Materials Chemistry Fluorescent protein Physical and Theoretical Chemistry Fourier transform infrared spectroscopy Absorption (electromagnetic radiation) 03 Chemical Sciences |
| Popis: | Reaction intermediates in the green-to-red photoconversion of the photochromic fluorescent protein EosFP have been observed using high-intensity continuous blue illumination. An intermediate was identified through light induced accumulation that continues to convert the green form in subsequent darkness, putatively containing a tyrosyl radical, albeit with anomalously shifted features in both electronic and FTIR spectra. Lowering the pH to 5.5 significantly delays the decay of this tyrosyl intermediate, which is accompanied by Stark-shifted features in the electronic spectra of reactants and products. Vibrational mode assignments for the high frequency and fingerprint FTIR spectral regions of reaction intermediates support a proposed sequence of events where the newly formed Cα=Cβ ethylenic bond precedes modifications on the His62 imidazole ring and confirms a C=O(NH2) product group on Phe61. We propose a reaction mechanism that involves tyrosyl generation via singlet excited state mediated oxidation which subsequently triggers the covalent reactions by oxidation of the green chromophore. |
| Databáze: | OpenAIRE |
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