Flavin mononucleotide fluorescence intensity decay in concentrated aqueous solutions

Ultrafast Excited-state Deactivation of Flavins Bound to Dodecin

“…Even though the positions of the riboflavin absorption bands are very sensitive to the environment (30), only small shifts of the absorption maxima of oxidized flavins have been observed for flavin dimers in solution (21) and a number of other flavoproteins (31,32). Accordingly, steady-state spectroscopy for dodecin shows that the riboflavin absorption band at 445 nm (S 0 3 S 1 transition is only marginally blue-shifted compared with free riboflavin in aqueous solution, and the band at 373 nm (S 0 3 S 2 transition) shows no shift of the absorption maximum (Fig.…”

“…For evaluation of the involvement of the stacked flavin in the quenching pathway, we used the properties of HsDod A to incorporate only one FAD molecule per binding pocket. In solution, fluorescence self-quenching of riboflavin of high concentrations due to dimerization is a common phenomenon (21,30,44). The distance between the two isoalloxazine moieties in the HsDod A binding pocket is only 3.2 Å, and selfquenching effects of dodecin bound riboflavin similar to riboflavin dimers in solution might be involved in dodecin photochemistry.…”

“…Because the concept of ultrafast electron transfer between flavins and closely positioned aromates like adenine, tryptophan, and tyrosine is well established in flavin photochemistry (9, 14 -20), a similar process involving electron transfer from the adjacent tryptophan to the photoexcited flavin can be assumed for dodecin. However, in this contribution, the role of the unique dimeric arrangement of the isoalloxazines, the possibility of riboflavin fluorescence selfquenching (21), the function of other residues in the binding pocket, and a putative more complex quenching reaction comprising electron and proton transfer (20) are evaluated on its impact on the HsDod A photophysical properties.…”

Resonance energy transfer between FMN molecules in the presence of dimers: A review

“…At high concentrations flavins form dimers. The examinations showed that FMN in aqueous solutions [62,63] and in rigid solutions (PVA) [61,37], even at extremely high concentrations, does not form aggregates higher than dimers. The absorption spectra of dimers ( Fig.…”

“…Investigations on excitation states of flavins, their quantum efficiency [74,75], their lifetime in the excited state [63,75], and the polarization of fluorescence [37,70] or ways of nonradiative energy transfer [37,68], can be important for explaining the photoreception phenomena in which flavins take part. Flavins show a strong tendency to generate triplet states that might give rise to additional photochemistry or energy dissipation because their triplet states are particularly photoreactive [58,75,76].…”