Femtosecond-to-nanosecond dynamics of flavin mononucleotide monitored by stimulated Raman spectroscopy and simulations
Artikel i vetenskaplig tidskrift, 2020

Flavin mononucleotide (FMN) belongs to the large family of flavins, ubiquitous yellow-coloured biological chromophores that contain an isoalloxazine ring system. As a cofactor in flavoproteins, it is found in various enzymes and photosensory receptors, like those featuring the light-oxygen-voltage (LOV) domain. The photocycle of FMN is triggered by blue light and proceeds via a cascade of intermediate states. In this work, we have studied isolated FMN in an aqueous solution in order to elucidate the intrinsic electronic and vibrational changes of the chromophore upon excitation. The ultrafast transitions of excited FMN were monitored through the joint use of femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption spectroscopy encompassing a time window between 0 ps and 6 ns with 50 fs time resolution. Global analysis of the obtained transient visible absorption and transient Raman spectra in combination with extensive quantum chemistry calculations identified unambiguously the singlet and triplet FMN populations and addressed solvent dynamics effects. The good agreement between the experimental and theoretical spectra facilitated the assignment of electronic transitions and vibrations. Our results represent the first steps towards more complex experiments aimed at tracking structural changes of FMN embedded in light-inducible proteins upon photoexcitation.

Författare

Prokopis C. Andrikopoulos

Czech Academy of Sciences

Yingliang Liu

Czech Academy of Sciences

Alessandra Picchiotti

Czech Academy of Sciences

Nils Lenngren

Czech Academy of Sciences

Miroslav Kloz

Czech Academy of Sciences

Aditya S. Chaudhari

Czech Academy of Sciences

Martin Precek

Czech Academy of Sciences

Mateusz Rebarz

Czech Academy of Sciences

Jakob Andreasson

Chalmers, Fysik, Kondenserade materiens fysik

Czech Academy of Sciences

Janos Hajdu

Uppsala universitet

Czech Academy of Sciences

Bohdan Schneider

Czech Academy of Sciences

Gustavo Fuertes

Czech Academy of Sciences

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 22 12 6538-6552

Ämneskategorier

Fysikalisk kemi

DOI

10.1039/c9cp04918e

PubMed

31994556

Mer information

Senast uppdaterat

2020-04-22