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Updated: Jun 10, 2026

Bioluminescent Optogenetics 2.0: Harnessing Bioluminescence to Activate Photosensory Proteins In Vitro and In Vivo
Published on: August 4, 2021
Excited-state intermolecular proton transfer of the firefly's chromophore D-luciferin
1Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel.
Abstract:
Steady-state absorption and emission as well as time-resolved emission spectroscopies were employed to study the photophysics and photochemistry of D-luciferin, the firefly active bioluminescent compound. In aqueous solution the electronically excited-state protonated D-luciferin compound undergoes an efficient process of proton transfer to the solvent, with a rate constant k(PT) = 3.0 x 10(10) s(-1). We found a kinetic isotope effect of about 2.5 for this process. The deprotonated form of D-luciferin in the excited state recombines irreversibly with the geminate proton. Hence, the fluorescence decay of the deprotonated form is nonexponential, and the fluorescence quantum yield is low.
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