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Theoretical Photodynamic Study of the Photoprotolytic Cycle of Firefly Oxyluciferin
Author(s) -
Pinto da Silva Luís,
Simkovitch Ron,
Huppert Dan,
Esteves da Silva Joaquim C. G.
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201300330
Subject(s) - chemistry , fluorescence , firefly protocol , stacking , excited state , aqueous solution , emission spectrum , ion , photochemistry , analytical chemistry (journal) , computational chemistry , spectral line , organic chemistry , atomic physics , zoology , physics , quantum mechanics , astronomy , biology
Firefly oxyluciferin presents a pH‐sensitive fluorescence in aqueous solutions. Its fluorescence spectra are composed of two green peaks at different pH values, despite the enolate anion being the only emitter. A computational approach was used to further elucidate the photoprotolytic cycle of oxyluciferin and investigate its pH sensitivity. It was found that oxyluciferin forms π–π stacking complexes both in the ground and excited states, at basic and acidic/neutral pH. However, at different pH values, these complexes adopt a different conformation, which explains the lower energy of the emission at acidic/neutral pH, in comparison with the emission at basic pH.