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Theoretical Study of the Wavelength Selection for the Photocleavage of Coumarin‐caged D‐luciferin
Author(s) -
Usukura Junko,
Hiyama Miyabi,
Kurata Maki,
Hazama Yuji,
Qiu XingPing,
Winnik Francoise M.,
Akiyama Hidefumi,
Koga Nobuaki
Publication year - 2020
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.13212
Subject(s) - luciferin , conformational isomerism , chemistry , excited state , photochemistry , moiety , aqueous solution , wavelength , visible spectrum , stereochemistry , molecule , organic chemistry , atomic physics , materials science , physics , optoelectronics , luciferase , transfection , biochemistry , gene
The equilibrium structures and optical properties of the photolabile caged luciferin, (7‐diethylaminocoumarin‐4‐yl)methyl caged D‐luciferin (DEACM‐caged D‐luciferin), in aqueous solution were investigated via quantum chemical calculations. The probable conformers of DEACM‐caged D‐luciferin were determined by potential energy curve scans and structural optimizations. We identified 40 possible conformers of DEACM‐caged D‐luciferin in water by comparing the Gibbs free energy of the optimized structures. Despite the difference in their structures, the conformers were similar in terms of assignments, oscillator strengths and energies of the three low‐lying excited states. From the concentrations of the conformers and their oscillator strengths, we obtained a theoretical UV/Vis spectrum of DEACM‐caged D‐luciferin that has two main bands of shape nearly identical to the experimental UV/Vis spectrum. The absorption bands with maxima ~ 384 and 339 nm were attributed to the electronic excitations of the caged group and the luciferin moiety, respectively, by analysis of the theoretical UV/Vis spectrum. Furthermore, the analysis showed that DEACM‐caged D‐luciferin is excited in the caged group only by light of wavelength ranging within 400–430 nm, which is in the long‐wavelength tail of the 384 nm band. This should be tested to lower damage upon photocleavage.