1
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Kumar G, Kellogg M, Dey S, Oliver TAA, Bradforth SE. Unraveling the Photoionization Dynamics of Indole in Aqueous and Ethanol Solutions. J Phys Chem B 2024; 128:4158-4170. [PMID: 38655896 DOI: 10.1021/acs.jpcb.4c01223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The photoionization dynamics of indole, the ultraviolet-B chromophore of tryptophan, were explored in water and ethanol using ultrafast transient absorption spectroscopy with 292, 268, and 200 nm excitation. By studying the femtosecond-to-nanosecond dynamics of indole in two different solvents, a new photophysical model has been generated that explains many previously unsolved facets of indole's complex solution phase photochemistry. Photoionization is only an active pathway for indole in aqueous solution, leading to a reduction in the fluorescence quantum yield in water-rich environments, which is frequently used in biophysical experiments as a key signature of the protein-folded state. Photoionization of indole in aqueous solution was observed for all three pump wavelengths but via two different mechanisms. For 200 nm excitation, electrons are ballistically ejected directly into the bulk solvent. Conversely, 292 and 268 nm excitation populates an admixture of two 1ππ* states, which form a dynamic equilibrium with a tightly bound indole cation and electron-ion pair. The ion pair dissociates on a nanosecond time scale, generating separated solvated electrons and indole cations. The charged species serve as important precursors to triplet indole production and greatly enhance the overall intersystem crossing rate. Our proposed photophysical model for indole in aqueous solution is the most appropriate for describing photoinduced dynamics of tryptophan in polypeptide sequences; tryptophan in aqueous pH 7 solution is zwitterionic, unlike in peptides, and resultantly has a competitive excited state proton transfer pathway that quenches the tryptophan fluorescence.
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Affiliation(s)
- Gaurav Kumar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Michael Kellogg
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Shivalee Dey
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Thomas A A Oliver
- School of Chemistry, Cantock's Close, University of Bristol, Bristol BS8 1TS, U.K
| | - Stephen E Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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2
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Jaiswal VK, Kabaciński P, Nogueira de Faria BE, Gentile M, de Paula AM, Borrego-Varillas R, Nenov A, Conti I, Cerullo G, Garavelli M. Environment-Driven Coherent Population Transfer Governs the Ultrafast Photophysics of Tryptophan. J Am Chem Soc 2022; 144:12884-12892. [PMID: 35796759 PMCID: PMC9305959 DOI: 10.1021/jacs.2c04565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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By combining UV transient
absorption spectroscopy with sub-30-fs
temporal resolution and CASPT2/MM calculations, we present a complete
description of the primary photoinduced processes in solvated tryptophan.
Our results shed new light on the role of the solvent in the relaxation
dynamics of tryptophan. We unveil two consecutive coherent population
transfer events involving the lowest two singlet excited states: a
sub-50-fs nonadiabatic La → Lb transfer
through a conical intersection and a subsequent 220 fs reverse Lb → La transfer due to solvent-assisted adiabatic
stabilization of the La state. Vibrational fingerprints
in the transient absorption spectra provide compelling evidence of
a vibronic coherence established between the two excited states from
the earliest times after photoexcitation and lasting until the back-transfer
to La is complete. The demonstration of response to the
environment as a driver of coherent population dynamics among the
excited states of tryptophan closes the long debate on its solvent-assisted
relaxation mechanisms and extends its application as a local probe
of protein dynamics to the ultrafast time scales.
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Affiliation(s)
- Vishal Kumar Jaiswal
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Piotr Kabaciński
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | | | - Marziogiuseppe Gentile
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Ana Maria de Paula
- Departamento de Física, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte-MG, Brazil
| | - Rocio Borrego-Varillas
- Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Artur Nenov
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Irene Conti
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.,Istituto di Fotonica e Nanotecnologie, CNR-IFN, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marco Garavelli
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
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3
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Soorkia S, Jouvet C, Grégoire G. UV Photoinduced Dynamics of Conformer-Resolved Aromatic Peptides. Chem Rev 2019; 120:3296-3327. [DOI: 10.1021/acs.chemrev.9b00316] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Satchin Soorkia
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Christophe Jouvet
- CNRS, Aix Marseille Université, PIIM UMR 7345, 13397, Marseille, France
| | - Gilles Grégoire
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
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4
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McCaslin TG, Pagba CV, Chi SH, Hwang HJ, Gumbart JC, Perry JW, Olivieri C, Porcelli F, Veglia G, Guo Z, McDaniel M, Barry BA. Structure and Function of Tryptophan-Tyrosine Dyads in Biomimetic β Hairpins. J Phys Chem B 2019; 123:2780-2791. [PMID: 30888824 PMCID: PMC6463897 DOI: 10.1021/acs.jpcb.8b12452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
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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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Affiliation(s)
| | | | | | | | | | | | | | - Fernando Porcelli
- Department for Innovation in Biological, Agro-Food and Forest Systems , University of Tuscia , 01100 Viterbo , Italy
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5
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Roy A, Seidel R, Kumar G, Bradforth SE. Exploring Redox Properties of Aromatic Amino Acids in Water: Contrasting Single Photon vs Resonant Multiphoton Ionization in Aqueous Solutions. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.7b11762] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anirban Roy
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Robert Seidel
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
- Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Gaurav Kumar
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | - Stephen E. Bradforth
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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6
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Kumar G, Roy A, McMullen RS, Kutagulla S, Bradforth SE. The influence of aqueous solvent on the electronic structure and non-adiabatic dynamics of indole explored by liquid-jet photoelectron spectroscopy. Faraday Discuss 2018; 212:359-381. [DOI: 10.1039/c8fd00123e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoelectron spectroscopy (TRPES) in a liquid micro-jet is implemented here to investigate the influence of water on the electronic structure and dynamics of indole, the chromophore of the amino acid tryptophan.
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Affiliation(s)
- Gaurav Kumar
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
| | - Anirban Roy
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
| | - Ryan S. McMullen
- Department of Chemistry
- University of Southern California
- Los Angeles
- USA
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7
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Kurhuzenkau SA, Woodward AW, Yao S, Belfield KD, Shaydyuk YO, Sissa C, Bondar MV, Painelli A. Ultrafast spectroscopy, superluminescence and theoretical modeling of a two-photon absorbing fluorene derivative. Phys Chem Chem Phys 2016; 18:12839-46. [DOI: 10.1039/c6cp01393g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Linear and nonlinear optical properties and photostability of a fluorene derivative are studied and rationalized within essential state models.
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Affiliation(s)
| | - A. W. Woodward
- Department of Chemistry
- University of Central Florida
- Orlando
- USA
| | - S. Yao
- Department of Chemistry
- University of Central Florida
- Orlando
- USA
| | - K. D. Belfield
- College of Science and Liberal Arts
- New Jersey Institute of Technology
- University Heights
- Newark
- USA
| | - Y. O. Shaydyuk
- Institute of Physics National Academy of Science of Ukraine
- Kiev-28
- Ukraine
| | - C. Sissa
- Department of Chemistry
- University of Parma
- Parma
- Italy
| | - M. V. Bondar
- Institute of Physics National Academy of Science of Ukraine
- Kiev-28
- Ukraine
| | - A. Painelli
- Department of Chemistry
- University of Parma
- Parma
- Italy
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8
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Mathes T, Heilmann M, Pandit A, Zhu J, Ravensbergen J, Kloz M, Fu Y, Smith BO, Christie JM, Jenkins GI, Kennis JTM. Proton-Coupled Electron Transfer Constitutes the Photoactivation Mechanism of the Plant Photoreceptor UVR8. J Am Chem Soc 2015; 137:8113-20. [DOI: 10.1021/jacs.5b01177] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tilo Mathes
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Monika Heilmann
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Anjali Pandit
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Department
of Solid-State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg
55, 2333 CC Leiden, The Netherlands
| | - Jingyi Zhu
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Janneke Ravensbergen
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Miroslav Kloz
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Yinan Fu
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Brian O. Smith
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - John M. Christie
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Gareth I. Jenkins
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - John T. M. Kennis
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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9
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Ajdarzadeh A, Consani C, Bräm O, Tortschanoff A, Cannizzo A, Chergui M. Ultraviolet transient absorption, transient grating and photon echo studies of aqueous tryptophan. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.01.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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10
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Alata I, Bert J, Broquier M, Dedonder C, Feraud G, Grégoire G, Soorkia S, Marceca E, Jouvet C. Electronic Spectra of the Protonated Indole Chromophore in the Gas Phase. J Phys Chem A 2013; 117:4420-7. [DOI: 10.1021/jp402298y] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ivan Alata
- Atomic Energy Commission of Syria, P.O. Box 6091, Damascus, Syria
| | - Johan Bert
- PIIM, Aix-Marseille Université, UMR-CNRS 7345, Avenue Escadrille
Normandie-Niémen, 13397 Marseille cedex 20, France
| | | | - Claude Dedonder
- PIIM, Aix-Marseille Université, UMR-CNRS 7345, Avenue Escadrille
Normandie-Niémen, 13397 Marseille cedex 20, France
| | - Géraldine Feraud
- PIIM, Aix-Marseille Université, UMR-CNRS 7345, Avenue Escadrille
Normandie-Niémen, 13397 Marseille cedex 20, France
| | - Gilles Grégoire
- Laboratoire de Physique des
Lasers, Université Paris 13, Sorbonne Paris Cité, CNRS, 93430 Villetaneuse, France
| | | | - Ernesto Marceca
- INQUIMAE-FCEN, UBA, Ciudad Universitaria, 3er piso, Pabellón II, 1428 Buenos
Aires, Argentina
| | - Christophe Jouvet
- PIIM, Aix-Marseille Université, UMR-CNRS 7345, Avenue Escadrille
Normandie-Niémen, 13397 Marseille cedex 20, France
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11
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Rondi A, Bonacina L, Trisorio A, Hauri C, Wolf JP. Coherent manipulation of free amino acids fluorescence. Phys Chem Chem Phys 2012; 14:9317-22. [PMID: 22395710 DOI: 10.1039/c2cp23357f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coherent manipulation of molecular wavepackets in biomolecules might contribute to the quest towards label-free cellular imaging and protein identification. We report the use of optimally tailored UV laser pulses in pump-probe depletion experiments that selectively enhance or decrease fluorescence between two aromatic amino acids: tryptophan (Trp) and tyrosine (Tyr). Selective fluorescence modulation is achieved with a contrast of ~35%. A neat modification of the time-dependent fluorescence depletion signal of Trp is observed, while the Tyr transient trace remains unchanged. The mechanism invoked for explaining the change of the depletion of Trp is a less efficient coupling between the fluorescing state and the higher non-radiative excited states by the optimally shaped pulse, than by the reference pulse.
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Affiliation(s)
- A Rondi
- GAP-Biophotonics, University of Geneva, 22 ch. de Pinchat, CH-1211 Geneva 4, Switzerland
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12
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Gelot T, Tourón-Touceda P, Crégut O, Léonard J, Haacke S. Ultrafast site-specific fluorescence quenching of 2-aminopurine in a DNA hairpin studied by femtosecond down-conversion. J Phys Chem A 2012; 116:2819-25. [PMID: 22289047 DOI: 10.1021/jp212187m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ΔP(-)PBS analog of the DNA primary binding sequence (PBS) of the HIV-1 genome labeled at different positions by 2-aminopurine (2-AP) is investigated by a novel femtosecond fluorescence down-conversion experiment with 0.3-ps time resolution. The high signal-to-noise ratio of the fluorescence kinetics makes it possible to reveal four distinct decay times ranging from 0.8 ps to 2-3 ns for all the three labeling positions. This suggests the existence of at least four different quenching conformations of 2-AP with its nearest neighbors, and underscores the structural heterogeneity of the loop region of ΔP(-)PBS. Sub-5-ps components are found and attributed to stacking interactions of 2-AP with the flanking guanine (G) side chains, consistent with the NMR structure of ΔP(-)PBS. The observation of a significant increase of their total amplitude when 2-AP is positioned close to the rigid 3'-half of the G-rich stem gives further support to this assignment. Only a minor portion of conformations involves slow nanosecond collisional quenching.
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Affiliation(s)
- Thomas Gelot
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg- CNRS, 67034 Strasbourg, France
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13
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Huijser A, Rode MF, Corani A, Sobolewski AL, Sundström V. Photophysics of indole-2-carboxylic acid in an aqueous environment studied by fluorescence spectroscopy in combination with ab initio calculations. Phys Chem Chem Phys 2012; 14:2078-86. [DOI: 10.1039/c2cp22958g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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14
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Oliver TAA, Zhang Y, Ashfold MNR, Bradforth SE. Linking photochemistry in the gas and solution phase: S–H bond fission in p-methylthiophenol following UV photoexcitation. Faraday Discuss 2011; 150:439-58; discussion 505-32. [DOI: 10.1039/c0fd00031k] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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15
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Gindensperger E, Haegy A, Daniel C, Marquardt R. Ab initio study of the electronic singlet excited-state properties of tryptophan in the gas phase: The role of alanyl side-chain conformations. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.07.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Léonard J, Sharma D, Szafarowicz B, Torgasin K, Haacke S. Formation dynamics and nature of tryptophan's primary photoproduct in aqueous solution. Phys Chem Chem Phys 2010; 12:15744-50. [DOI: 10.1039/c0cp00615g] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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