Investigating the Ultrafast Dynamics and Long-Term Photostability of an Isomer Pair, Usujirene and Palythene, from the Mycosporine-like Amino Acid Family

Mycosporine-like amino acids are a prevalent form of photoprotection in micro- and macro-organisms. Using a combination of natural product extraction/purification and femtosecond transient absorption spectroscopy, we studied the relaxation pathway for a common mycosporine-like amino acid pair, usujirene and its geometric isomer palythene, in the first few nanoseconds following photoexcitation. Our studies show that the electronic excited state lifetimes of these molecules persist for only a few hundred femtoseconds before the excited state population is funneled through an energetically accessible conical intersection with subsequent vibrational energy transfer to the solvent. We found that a minor portion of the isomer pair did not recover to their original state within 3 ns after photoexcitation. We investigated the long-term photostability using continuous irradiation at a single wavelength and with a solar simulator to mimic a more real-life environment; high levels of photostability were observed in both experiments. Finally, we employed computational methods to elucidate the photochemical and photophysical properties of usujirene and palythene as well as to reconcile the photoprotective mechanism. View Full-Text

Keywords: mycosporine-like amino acids; usujirene; palythene; ultrafast spectroscopy; photophysics; photochemistry

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Whittock, A.L.; Woolley, J.M.; Auckloo, N.; Corre, C.; Stavros, V.G. Investigating the Ultrafast Dynamics and Long-Term Photostability of an Isomer Pair, Usujirene and Palythene, from the Mycosporine-like Amino Acid Family. Molecules 2022, 27, 2272. https://doi.org/10.3390/molecules27072272

AMA Style

Whittock AL, Woolley JM, Auckloo N, Corre C, Stavros VG. Investigating the Ultrafast Dynamics and Long-Term Photostability of an Isomer Pair, Usujirene and Palythene, from the Mycosporine-like Amino Acid Family. Molecules. 2022; 27(7):2272. https://doi.org/10.3390/molecules27072272

Chicago/Turabian Style

Whittock, Abigail L., Jack M. Woolley, Nazia Auckloo, Christophe Corre, and Vasilios G. Stavros. 2022. "Investigating the Ultrafast Dynamics and Long-Term Photostability of an Isomer Pair, Usujirene and Palythene, from the Mycosporine-like Amino Acid Family" Molecules 27, no. 7: 2272. https://doi.org/10.3390/molecules27072272

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Investigating the Ultrafast Dynamics and Long-Term Photostability of an Isomer Pair, Usujirene and Palythene, from the Mycosporine-like Amino Acid Family

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