Study of coelenterazine luminescence: Electrostatic interactions as the controlling factor for efficient chemiexcitation

• Tipo: Artigo em Revista Científica Internacional
• Data: 2018

Autores

Magalhaes, CM (Autor) Outra; Joaquim C G E Esteves da Silva (Autor) FCUP; da Silva, LP (Autor) FCUP

Revista

Título: Journal of Luminescence

Vol. 199

Páginas: 339-347

ISSN: 0022-2313

Editora: Elsevier

Indexação

ISI Web of Knowledge - 22 Citações

Scopus - 22 Citações

Outras Informações

ID Authenticus: P-00N-SQA

DOI: 10.1016/j.jlumin.2018.03.069

Abstract (EN): Coelenterazine is a common substrate used by marine species in enzyme-catalyzed bioluminescent reactions, in which thermal energy is converted into excitation energy. Coelenterazine is also known to emit chemiluminescence, in the absence of enzymes. Moreover, the scaffold of this molecule is present in organisms of eight phyla, making it a prototypical system for marine chemi-/bioluminescence. The characterization of the chemiexcitation step responsible for light emission is essential for future applications in bioimaging, bioanalysis and biomedicine. We have found evidence to support the identification of a neutral dioxetanone intermediate as the responsible for efficient chemiexcitation. This is explained by attractive electrostatic interactions between the CO2 and Coelenteramide moieties, which allow the reacting dioxetanone to spend time in a PES region of degeneracy between singlet ground and excited states. Contrary to expected, there is no relationship between electron (ET)/charge (CT) transfer, from an electron-rich moiety to the peroxide, and efficient chemiexcitation. Thus, neither Chemically Induced Electron-Exchange Luminescence (CIEEL) nor Charge Transfer-Initiated Luminescence (CTIL) can be used to explain imidazopyrazinone-based chemi-/bioluminescence. We have also found a concentration-dependent quenching effect, more prevalent at acidic pH.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9