Ultraviolet fluorescence of coelenteramide and coelenteramide-containing fluorescent proteins. Experimental and theoretical study


Тип публикации: статья из журнала

Год издания: 2016

Идентификатор DOI: 10.1016/j.jphotobiol.2016.07.004

Ключевые слова: Coelenteramide, Fluorescent protein, Discharged photoproteins, Obelin, Aequorin, Fluorescence, Excitation energy, B3LYP, acetamide derivative, aromatic amino acid, clytin, methanol, photoprotein, unclassified drug, Article, experimental study, fluorescence spectroscopy, priority journal, quantum yield, theoretical study, ultraviolet A radiation, ultraviolet fluorescence

Аннотация: Coelenteramide-containing fluorescent proteins are products of bioluminescent reactions of marine coelenterates. They are called 'discharged photoproteins'. Their light-induced fluorescence spectra are variable, depending considerably on external conditions. Current work studies a dependence of light-induced fluorescence spectra ofПоказать полностьюdischarged photoproteins obelin, aequorin, and clytin on excitation energy. It was demonstrated that photoexcitation to the upper electron-excited states (260-300 nm) of the discharged photoproteins initiates a fluorescence peak in the near UV region, in addition to the blue-green emission. To characterize the UV fluorescence, the light-induced fluorescence spectra of coelenteramide (CLM), fluorophore of the discharged photoproteins, were studied in methanol solution. Similar to photoproteins, the CLM spectra depended on photoexcitation energy; the additional peak (330 nm) in the near UV region was observed in CLM fluorescence at higher excitation energy (260-300 nm). Quantum chemical calculations by time depending method with B3LYP/cc-pVDZ showed that the conjugated pyrazine-phenolic fragment and benzene moiety of CLM molecule are responsible for the additional UV fluorescence peak. Quantum yields of CLM fluorescence in methanol were 0.028 +/- 0.005 at 270-340 nm photoexcitation. A conclusion was made that the UV emission of CLM might contribute to the UV fluorescence of the discharged photoproteins. The study develops knowledge on internal energy transfer in biological structures - complexes of proteins with low-weight aromatic molecules. (C) 2016 Elsevier B.V. All rights reserved.

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Выпуск журнала: Vol. 162

Номера страниц: 318-323

ISSN журнала: 10111344

Место издания: LAUSANNE