A Theoretical Analysis of the Potential Role of pi-pi Stacking Interactions in the Photoprotolytic Cycle of Firefly Luciferin

• Type: Article in International Scientific Journal
• Date: 2014

Authors

da silva, lp (Author) Other; esteves da silva, jcge (Author) FCUP

Journal

Title: ChemPhysChem

Vol. 15

Pages: 3761-3767

ISSN: 1439-4235

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 2 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-00A-0M3

DOI: 10.1002/cphc.201402558

Abstract (EN): Firefly oxyluciferin is a photoacid that presents a pH-sensitive fluorescence, which results from pH-dependent changes on the conformation of self-aggregated - stacking complexes. Luciferin is a derivative of oxyluciferin with very similar fluorescence and photoacidic properties. This similarity indicates that luciferin is also expected to be able to form - stacking complexes, but no pH-sensitive fluorescence is found for this compound. Here, a theoretical approach is used to rationalize this finding. We have found that luciferin only forms - stacking complexes in the ground state at acidic pH. At basic pH and in the excited state, luciferin is present as a dianion. This species is not able to self-aggregate, owing to repulsive electrostatic interactions. Thus, this emissive species is not subject to - stacking interactions; this explains its pH-insensitive fluorescence.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7