title: Chemiexcitation induced proton transfer: enolate oxyluciferin as the firefly bioluminophore.
abstract: Firefly bioluminescence is a phenomenon that attracts attention from the research community because of complex challenges for fundamental investigation, as well as diverse opportunities for practical application. Here we have studied the potential deprotonation of firefly oxyluciferin by using a theoretical approach in an enzymatic-like microenvironment in chemiexcited proton transfer involving adenosine 5'-monophosphate. We have uncovered a reaction route that links the evidence that the light-emitter is an anionic molecule while it is chemiexcited in its neutral form. Moreover, the results indicated that the anionic bioluminophore is the enolate anion and not the ketonic one. Further calculations supported this identification of the light-emitter: the spectrum of resulting enolate anion covers the entire yellow-green/red bioluminescence range, which is in line with the experimental findings regarding firefly multicolor bioluminescence.
authors.affiliation: Centro de Investigação em Química, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto , R. Campo Alegre 687, 4169-007 Porto, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Pinto da Silva
authors.forename: Joaquim C G
authors.initials: JC
authors.lastname: Esteves da Silva
mesh_terms: D000818:Animals; D004735:Energy Transfer; D048888:Fireflies; D007211:Indoles / Q000737:chemistry*; D049449:Luminescence; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D011719:Pyrazines / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D007211:Indoles; D011522:Protons; D011719:Pyrazines; C014730:oxyluciferin