Ultrafast Nonradiative Relaxation Channels of Tryptophan

Ovejas, Virginia; Fernández-Fernández, Marta; Montero, Raúl; Castaño, Fernando; Longarte, Asier

doi:10.1021/jz400810j

Cited by 17 publications

(21 citation statements)

References 41 publications

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“…With other chromophores, the most stable conformer of natural Trp was shown to exhibit specific excited fluorescence behaviour, interpreted as a conformer-selective coupling between L b and L a states [59,211], although this rationalisation was later disputed [20]. Confirmation of this excitedstate dynamics was obtained from time-resolved experiments [212]. To our knowledge, no conformer-selective lifetime measurements have been reported for Trp-or Tyr-related capped compounds.…”

Section: Photophysics Of Aromatic Residues In Model Peptidesmentioning

confidence: 97%

Isolated Neutral Peptides

Gloaguen

Mons

2014

Topics in Current Chemistry

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This chapter examines the structural characterisation of isolated neutral amino-acids and peptides. After a presentation of the experimental and theoretical state-of-the-art in the field, a review of the major structures and shaping interactions is presented. Special focus is made on conformationally-resolved studies which enable one to go beyond simple structural characterisation; probing flexibility and excited-state photophysics are given as examples of promising future directions.

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Section: Photophysics Of Aromatic Residues In Model Peptidesmentioning

confidence: 97%

Isolated Neutral Peptides

Gloaguen

Mons

2014

Topics in Current Chemistry

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“…[1][2][3][4][5] While in the ion integrated detection schemes the molecular response engages simultaneously the contribution of all the involved states, those based in energy resolved photoelectron detection permit to track the evolution of individual vibro-electronic states. [6][7][8][9] In parallel to the development of the experimental techniques, the theoretical modeling of the observables extracted from time-resolved ionization methods has been faced by a considerable number of studies.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the relaxation dynamics of isolated pyrrole

Montero

Ovejas

Fernández-Fernández

et al. 2014

The Journal of Chemical Physics

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Herein, the interpretation of the femtosecond-scale temporal evolution of the pyrrole ion signal, after excitation in the 267-217 nm interval, recently published by our group [R. Montero, A. Peralta Conde, V. Ovejas, M. Fernández-Fernández, F. Castaño, J. R. Vázquez de Aldana, and A. Longarte, J. Chem. Phys. 137, 064317 (2012)] is re-visited. The observation of a shift in the pyrrole(+) transient respect to zero delay reference, initially attributed to ultrafast dynamics on the πσ* type state (3s a1 ← π 1a2), is demonstrated to be caused by the existence of pump + probe populated states, along the ionization process. The influence of these resonances in pump-prone ionization experiments, when multi-photon probes are used, and the significance of a proper zero-time reference, is discussed. The possibility of preparing the πσ* state by direct excitation is investigated by collecting 1 + 1 photoelectron spectra, at excitation wavelengths ranging from 255 to 219 nm. No conclusive evidences of ionization through this state are found.

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“…The spectra that we report from tryptophan and tryptophan–tyrosine mixtures are similar to previous reports of the indole S 1 excited state, with absorption at 345/360 and 520 nm. 42 , 45 , 68 , 69 In tryptophan and in the mixture, the formation of a H + indole photoproduct is also evident as a 420 nm spectral feature that grows in ∼500 ps. The source of the proton has been attributed to the tryptophan amino group.…”

Section: Discussionmentioning

confidence: 99%

Structure and Function of Tryptophan–Tyrosine Dyads in Biomimetic β Hairpins

et al. 2019

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Tyrosine–tryptophan (YW) dyads are ubiquitous structural motifs in enzymes and play roles in proton-coupled electron transfer (PCET) and, possibly, protection from oxidative stress. Here, we describe the function of YW dyads in de novo designed 18-mer, β hairpins. In Peptide M, a YW dyad is formed between W14 and Y5. A UV hypochromic effect and an excitonic Cotton signal are observed, in addition to singlet, excited state (W*) and fluorescence emission spectral shifts. In a second Peptide, Peptide MW, a Y5–W13 dyad is formed diagonally across the strand and distorts the backbone. On a picosecond timescale, the W* excited-state decay kinetics are similar in all peptides but are accelerated relative to amino acids in solution. In Peptide MW, the W* spectrum is consistent with increased conformational flexibility. In Peptide M and MW, the electron paramagnetic resonance spectra obtained after UV photolysis are characteristic of tyrosine and tryptophan radicals at 160 K. Notably, at pH 9, the radical photolysis yield is decreased in Peptide M and MW, compared to that in a tyrosine and tryptophan mixture. This protective effect is not observed at pH 11 and is not observed in peptides containing a tryptophan–histidine dyad or tryptophan alone. The YW dyad protective effect is attributed to an increase in the radical recombination rate. This increase in rate can be facilitated by hydrogen-bonding interactions, which lower the barrier for the PCET reaction at pH 9. These results suggest that the YW dyad structural motif promotes radical quenching under conditions of reactive oxygen stress.

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Ultrafast Nonradiative Relaxation Channels of Tryptophan

Cited by 17 publications

References 41 publications

Isolated Neutral Peptides

Isolated Neutral Peptides

Revisiting the relaxation dynamics of isolated pyrrole

Structure and Function of Tryptophan–Tyrosine Dyads in Biomimetic β Hairpins

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