Influence of solvents and leucine configuration at position 5 on tryptophan fluorescence in cyclic enkephalin analogues

Malicka, Joanna; Groth, Małgorzata; Karolczak, Jerzy; Czaplewski, Cezary; Liwo, Adam; Wiczk, Wiesław

doi:10.1002/1097-0282(20010405)58:4<447::aid-bip1020>3.0.co;2-4

Cited by 9 publications

(4 citation statements)

References 78 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Oxidized FAD in solution exhibits two broad absorption bands, with peaks at 450 nm for S 0 →S 1 and at 375 nm for S 0 →S 2 , while the FMN enclosed in the flavodoxin mutant shows some peak features at 476, 454, and 432 nm in S 0 →S 1 and a broad band at 384 nm for S 0 →S 2 absorption. The emission peak of oxidized flavin is around 530 nm in solution and shifts to the blue side in a hydrophobic protein environment in flavodoxin (Figure A). , It has been reported that the fluorescence intensity of FAD* in solution is about 10-fold weaker than that of excited riboflavin and FMN, − due to intramolecular ET quenching with a stacked conformation between the isoalloxazine ring and the adenine moiety. Numerous experimental and theoretical studies − ,,− suggested that two FAD conformations, open and stacked, exist in solution (Figure A).…”

Section: Resultsmentioning

confidence: 96%

“…The emission peak of oxidized flavin is around 530 nm in solution and shifts to the blue side in a hydrophobic protein environment in flavodoxin (Figure 1A). 66,67 It has been reported that the fluorescence intensity of FAD* in solution is about 10-fold weaker than that of excited riboflavin and FMN, [44][45][46] due to intramolecular ET quenching with a stacked conformation between the isoalloxazine ring and the adenine moiety. Numerous experimental and theoretical studies [44][45][46]48,[68][69][70][71][72][73] suggested that two FAD conformations, open and stacked, exist in solution (Figure 1A).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Ultrafast Dynamics of Flavins in Five Redox States

et al. 2008

View full text Add to dashboard Cite

We report here our systematic studies of excited-state dynamics of two common flavin molecules, FMN and FAD, in five redox states of oxidized form, neutral and anionic semiquinones, and neutral and anionic fully-reduced hydroquinones in solution and in inert protein environments with femtosecond resolution. Using protein environments, we are able to stabilize two semiquinone radicals and thus observed their weak emission spectra. Significantly, we observed a strong correlation between their excited-state dynamics and the planarity of their flavin isoalloxazine ring. For a bent ring structure, we all observed ultrafast dynamics from a few to hundreds of picoseconds and strong excitation-wavelength dependence of emission spectra, indicating deactivation during relaxation. A butterfly bending motion is invoked to get access to conical intersection(s) to facilitate deactivation. These states include the anionic semiquinone radical and fully-reduced neutral and anionic hydroquinones in solution. In a planar configuration, flavins have a long lifetime in nanoseconds except for the stacked conformation of FAD, where the intramolecular electron transfer between the ring and the adenine moiety in 5-9 ps as well as the subsequent charge recombination in 30-40 ps were observed. These observed distinct dynamics, controlled by the flavin ring flexibility, are fundamental to flavoenzyme's functions as observed in photolyase with a planar structure to lengthen the lifetime to maximize DNA repair efficiency and in insect Type 1 cryptochrome with a flexible structure to vary the excited-state deactivation to modulate the functional channel.

show abstract

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Ultrafast Dynamics of Flavins in Five Redox States

et al. 2008

View full text Add to dashboard Cite

show abstract

“…3A). 67,68 It has been reported that the fluorescence intensity of excited FAD in solution is about 10-fold weaker than that of excited riboflavin or FMN, [69][70][71] owing to intramolecular ET quenching with a stacked conformation between the isoalloxazine ring and the adenine moiety. Numerous experimental and theoretical studies [69][70][71][72][73][74][75][76][77][78] suggested that two FAD conformations, open and stacked, exist in solution (Fig.…”

Section: Absorption and Emission Spectra Of Flavins In Various Redox ...mentioning

confidence: 99%

Dynamics and mechanisms of DNA repair by photolyase

Liu

Wang

Zhong

2015

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

Photolyase, a class of flavoproteins, uses blue light to repair two types of ultraviolet-induced DNA damage, cyclobutane pyrimidine dimer (CPD) and pyrimidine-pyrimidone (6–4) photoproduct (6–4PP). In this perspective, we review the recent progress on the repair dynamics and mechanisms of both types of DNA restoration by photolyases. We first report the spectroscopic characterization of flavin in various redox states and the active-site solvation dynamics in photolyases. We then systematically summarize the detailed repair dynamics of damaged DNA by photolyases and a biomimetic system through resolving all elementary steps on the ultrafast timescales, including multiple intermolecular electron- and proton-transfer reactions and bond-breaking and -making processes. We determined the unique electron tunneling pathways, identified the key functional residues and revealed the molecular origin of high repair efficiency, and thus elucidate the molecular mechanisms and repair photocycles at the most fundamental level. We finally conclude that the active sites of photolyases, unlike aqueous solution for the biomimetic system, provide a unique electrostatic environment and local flexibility and thus a dedicated synergy for all elementary dynamics to maximize the repair efficiency. This repair photomachine is the first enzyme that the entire functional evolution is completely mapped out in real time.

show abstract

“…A combined theoretical-NMR approach was undertaken to obtain conformational ensembles of the cyclic enkephalin analogues H-c[D-Dab 2 -Gly 3 5 ] in water and dimethyl sulfoxide (DMSO) [125]. The algorithm consisted of the following three steps: (i) search of the conformational space to find conformations with reasonably low energy; (ii) simulation of the NOE spectrum and vicinal coupling constants for each of the low energy conformations; and (iii) determining the statistical weights of the conformations, by means of the maximumentropy method, in order to obtain the best fit of the averaged NOE intensities and coupling constants to the experimental quantities [126].…”

Section: Rotamer Distributionsmentioning

confidence: 99%

How Do Rotameric Conformations Influence the Time-Resolved Fluorescence of Tryptophan in Proteins? A Perspective Based on Molecular Modeling and Quantum Chemistry

Moors¹,

Jonckheer²,

Maeyer³

et al. 2008

CPPS

View full text Add to dashboard Cite

We discuss the dynamics of tryptophan rotamers in the context of the non-exponential fluorescence decay in proteins. The central question is: how does the ground-state conformational heterogeneity influence the time evolution of tryptophan fluorescence? This problem is examined here from the theoretical perspective. Three methods at different levels of theory, and with different scopes and computational requirements are reviewed. The Dead-end elimination method is limited to side-chain dynamics and provides an efficient way to detect the stable tryptophan rotamers in a protein. Its application to the study of heterogeneous emission characteristics is illustrated. Molecular dynamics is aimed at the full phase space of the macromolecule in solution, but must rely on classical force fields and laws of evolution. We examine to what extent the molecular mechanics paradigm yields sufficiently accurate thermodynamic results, and what are the possible kinetic implications. Finally Quantum Chemistry is the only theoretical method that allows a direct assessment of the excited states. It is necessarily restricted to small molecular systems, and thus must be used in a hybrid combination with classical methods and electrostatic models. So far understanding of the emitting state has greatly progressed as a result of these calculations, but the actual treatment of the photophysical decay processes at the quantum level has not yet really started.

show abstract

Influence of solvents and leucine configuration at position 5 on tryptophan fluorescence in cyclic enkephalin analogues

Cited by 9 publications

References 78 publications

Ultrafast Dynamics of Flavins in Five Redox States

Ultrafast Dynamics of Flavins in Five Redox States

Dynamics and mechanisms of DNA repair by photolyase

How Do Rotameric Conformations Influence the Time-Resolved Fluorescence of Tryptophan in Proteins? A Perspective Based on Molecular Modeling and Quantum Chemistry

Contact Info

Product

Resources

About