1
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Abstract
Endogenous photosensitizers play a critical role in both beneficial and harmful light-induced transformations in biological systems. Understanding their mode of action is essential for advancing fields such as photomedicine, photoredox catalysis, environmental science, and the development of sun care products. This review offers a comprehensive analysis of endogenous photosensitizers in human skin, investigating the connections between their electronic excitation and the subsequent activation or damage of organic biomolecules. We gather the physicochemical and photochemical properties of key endogenous photosensitizers and examine the relationships between their chemical reactivity, location within the skin, and the primary biochemical events following solar radiation exposure, along with their influence on skin physiology and pathology. An important take-home message of this review is that photosensitization allows visible light and UV-A radiation to have large effects on skin. The analysis presented here unveils potential causes for the continuous increase in global skin cancer cases and emphasizes the limitations of current sun protection approaches.
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Affiliation(s)
- Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Frank H Quina
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
- Department of Chemical Engineering, Polytechnic School, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
| | - Maurício S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, 05508-000 São Paulo, São Paulo, Brazil
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2
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A Review on Forced Degradation Strategies to Establish the Stability of Therapeutic Peptide Formulations. Int J Pept Res Ther 2023. [DOI: 10.1007/s10989-023-10492-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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3
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Rutz A, Das CK, Fasano A, Jaenecke J, Yadav S, Apfel UP, Engelbrecht V, Fourmond V, Léger C, Schäfer LV, Happe T. Increasing the O 2 Resistance of the [FeFe]-Hydrogenase CbA5H through Enhanced Protein Flexibility. ACS Catal 2022; 13:856-865. [PMID: 36733639 PMCID: PMC9886219 DOI: 10.1021/acscatal.2c04031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 12/08/2022] [Indexed: 12/29/2022]
Abstract
The high turnover rates of [FeFe]-hydrogenases under mild conditions and at low overpotentials provide a natural blueprint for the design of hydrogen catalysts. However, the unique active site (H-cluster) degrades upon contact with oxygen. The [FeFe]-hydrogenase fromClostridium beijerinckii (CbA5H) is characterized by the flexibility of its protein structure, which allows a conserved cysteine to coordinate to the active site under oxidative conditions. Thereby, intrinsic cofactor degradation induced by dioxygen is minimized. However, the protection from O2 is only partial, and the activity of the enzyme decreases upon each exposure to O2. By using site-directed mutagenesis in combination with electrochemistry, ATR-FTIR spectroscopy, and molecular dynamics simulations, we show that the kinetics of the conversion between the oxygen-protected inactive state (cysteine-bound) and the oxygen-sensitive active state can be accelerated by replacing a surface residue that is very distant from the active site. This sole exchange of methionine for a glutamate residue leads to an increased resistance of the hydrogenase to dioxygen. With our study, we aim to understand how local modifications of the protein structure can have a crucial impact on protein dynamics and how they can control the reactivity of inorganic active sites through outer sphere effects.
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Affiliation(s)
- Andreas Rutz
- Photobiotechnology,
Department of Plant Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany
| | - Chandan K. Das
- Theoretical
Chemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Andrea Fasano
- Laboratoire
de Bioénergétique et Ingénierie des Protéines, CNRS, Aix-Marseille Université, Institut de
Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Jan Jaenecke
- Photobiotechnology,
Department of Plant Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany
| | - Shanika Yadav
- Inorganic
Chemistry Ι, Department of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Ulf-Peter Apfel
- Inorganic
Chemistry Ι, Department of Chemistry and Biochemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany,Fraunhofer
UMSICHT, 46047 Oberhausen, Germany
| | - Vera Engelbrecht
- Photobiotechnology,
Department of Plant Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany
| | - Vincent Fourmond
- Laboratoire
de Bioénergétique et Ingénierie des Protéines, CNRS, Aix-Marseille Université, Institut de
Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Christophe Léger
- Laboratoire
de Bioénergétique et Ingénierie des Protéines, CNRS, Aix-Marseille Université, Institut de
Microbiologie de la Méditerranée, 13009 Marseille, France
| | - Lars V. Schäfer
- Theoretical
Chemistry, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Thomas Happe
- Photobiotechnology,
Department of Plant Biochemistry, Ruhr-Universität
Bochum, 44801 Bochum, Germany,
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4
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Furet A, Sicello A, Guillemat B, Absalon C, Langleron E, Bassani DM. Revisiting the mechanism responsible for the light-struck flavor in white wines and Champagnes. Food Chem 2022; 372:131281. [PMID: 34655832 DOI: 10.1016/j.foodchem.2021.131281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 11/04/2022]
Abstract
The mechanism responsible for the appearance of the light-struck fault upon exposure of white wines and Champagnes to natural or artificial light is examined in light of new experiments involving methionine analogues. The latter show that the formation of volatile sulfur species upon irradiation of riboflavin in the presence of methionine in model wine solutions at pH 3 is not dependent on the existence of neighboring group stabilization of the sulfur-centered cation radical through a 5- or 6-membered cyclic intermediate. Instead, the formation of a dimer radical cation is proposed in agreement with the formation of oxidation products such as dimethyl disulfide at early reaction times and the observed steric effect upon product distribution. The limiting quantum yield for the release of sulfur atoms from a solution of methionine in model wine solutions at pH 3.5 containing riboflavin was found to be 0.26 (435 nm irradiation). No dependence of the quantum yield or product distribution on the irradiation wavelength was found over the range 365-90 nm.
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Affiliation(s)
- Amaury Furet
- Univ. Bordeaux, CNRS UMR 5255, Inst. des Sciences Moléculaires, 351, Cours de la Libération, 33405 Talence, France
| | - Audrey Sicello
- Univ. Bordeaux, CNRS UMR 5255, Inst. des Sciences Moléculaires, 351, Cours de la Libération, 33405 Talence, France
| | - Bruno Guillemat
- Pernod-Ricard S.A., 5, cours Paul Ricard, 75008 Paris, France
| | - Christelle Absalon
- Univ. Bordeaux, CNRS UMR 5255, Inst. des Sciences Moléculaires, 351, Cours de la Libération, 33405 Talence, France
| | - Emilie Langleron
- Mumm, Perrier-Jouët, 34, Rue du Champ de Mars, 51053 Reims, France
| | - Dario M Bassani
- Univ. Bordeaux, CNRS UMR 5255, Inst. des Sciences Moléculaires, 351, Cours de la Libération, 33405 Talence, France.
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5
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Photo- and Radiation-Induced One-Electron Oxidation of Methionine in Various Structural Environments Studied by Time-Resolved Techniques. Molecules 2022; 27:molecules27031028. [PMID: 35164293 PMCID: PMC8915190 DOI: 10.3390/molecules27031028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/25/2022] Open
Abstract
Oxidation of methionine (Met) is an important reaction that plays a key role in protein modifications during oxidative stress and aging. The first steps of Met oxidation involve the creation of very reactive and short-lived transients. Application of complementary time-resolved radiation and photochemical techniques (pulse radiolysis and laser flash photolysis together with time-resolved CIDNP and ESR techniques) allowed comparing in detail the one-electron oxidation mechanisms initiated either by ●OH radicals and other one-electron oxidants or the excited triplet state of the sensitizers e.g., 4-,3-carboxybenzophenones. The main purpose of this review is to present various factors that influence the character of the forming intermediates. They are divided into two parts: those inextricably related to the structures of molecules containing Met and those related to external factors. The former include (i) the protection of terminal amine and carboxyl groups, (ii) the location of Met in the peptide molecule, (iii) the character of neighboring amino acid other than Met, (iv) the character of the peptide chain (open vs cyclic), (v) the number of Met residues in peptide and protein, and (vi) the optical isomerism of Met residues. External factors include the type of the oxidant, pH, and concentration of Met-containing compounds in the reaction environment. Particular attention is given to the neighboring group participation, which is an essential parameter controlling one-electron oxidation of Met. Mechanistic aspects of oxidation processes by various one-electron oxidants in various structural and pH environments are summarized and discussed. The importance of these studies for understanding oxidation of Met in real biological systems is also addressed.
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6
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Archirel P, Houée-Lévin C, Marignier JL. Radiolytic Oxidation of Two Inverse Dipeptides, Methionine-Valine and Valine-Methionine: A Joint Experimental and Computational Study. J Phys Chem B 2019; 123:9087-9097. [PMID: 31577444 DOI: 10.1021/acs.jpcb.9b07014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The two inverse peptides methionine-valine (Met-Val) and valine-methionine (Val-Met) are investigated in an oxidative radiolysis process in water. The OH radical yields products with very different absorption spectra and concentration effects: Met-Val yields one main product with a band at about 400 nm and other products at higher energies; there is no concentration effect. Val-Met yields at least three products, with a striking concentration effect. Molecular simulations are performed with a combination of the Monte Carlo, density functional theory, and reaction field methods. The simulation of the possible transients enables an interpretation of the radiolysis: (1) Met-Val undergoes an H atom uptake leaving mainly a neutral radical with a 2-center-3-electron (2c-3e) SN bond, which cannot dimerize. Other radicals are present at higher energies. (2) Val-Met undergoes mainly an electron uptake leaving a cation monomer with a (2c-3e) SO bond and a cation dimer with a (2c-3e) SS bond. At higher energies, neutral radicals are possible. This cation monomer can transfer a proton toward a neutral peptide, leaving a neutral radical.
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Affiliation(s)
- Pierre Archirel
- Laboratoire de Chimie Physique , CNRS UMR 8000, Université Paris-Sud, Université Paris-Saclay , F91405 Orsay , France
| | - Chantal Houée-Lévin
- Laboratoire de Chimie Physique , CNRS UMR 8000, Université Paris-Sud, Université Paris-Saclay , F91405 Orsay , France
| | - Jean-Louis Marignier
- Laboratoire de Chimie Physique , CNRS UMR 8000, Université Paris-Sud, Université Paris-Saclay , F91405 Orsay , France
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7
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Susceptibility of protein therapeutics to spontaneous chemical modifications by oxidation, cyclization, and elimination reactions. Amino Acids 2019; 51:1409-1431. [DOI: 10.1007/s00726-019-02787-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/07/2019] [Indexed: 12/12/2022]
Abstract
AbstractPeptides and proteins are preponderantly emerging in the drug market, as shown by the increasing number of biopharmaceutics already approved or under development. Biomolecules like recombinant monoclonal antibodies have high therapeutic efficacy and offer a valuable alternative to small-molecule drugs. However, due to their complex three-dimensional structure and the presence of many functional groups, the occurrence of spontaneous conformational and chemical changes is much higher for peptides and proteins than for small molecules. The characterization of biotherapeutics with modern and sophisticated analytical methods has revealed the presence of contaminants that mainly arise from oxidation- and elimination-prone amino-acid side chains. This review focuses on protein chemical modifications that may take place during storage due to (1) oxidation (methionine, cysteine, histidine, tyrosine, tryptophan, and phenylalanine), (2) intra- and inter-residue cyclization (aspartic and glutamic acid, asparagine, glutamine, N-terminal dipeptidyl motifs), and (3) β-elimination (serine, threonine, cysteine, cystine) reactions. It also includes some examples of the impact of such modifications on protein structure and function.
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8
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Ferrer-Sueta G, Campolo N, Trujillo M, Bartesaghi S, Carballal S, Romero N, Alvarez B, Radi R. Biochemistry of Peroxynitrite and Protein Tyrosine Nitration. Chem Rev 2018; 118:1338-1408. [DOI: 10.1021/acs.chemrev.7b00568] [Citation(s) in RCA: 292] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Gerardo Ferrer-Sueta
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Nicolás Campolo
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Madia Trujillo
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Silvina Bartesaghi
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Sebastián Carballal
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Natalia Romero
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Beatriz Alvarez
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
| | - Rafael Radi
- Laboratorio
de Fisicoquímica Biológica, Facultad de
Ciencias, ‡Center for Free Radical and Biomedical Research, §Departamento de Bioquímica,
Facultad de Medicina, ∥Laboratorio de Enzimología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay
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9
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Davis I, Koto T, Liu A. Radical Trapping Study of the Relaxation of bis-Fe(IV) MauG. REACTIVE OXYGEN SPECIES (APEX, N.C.) 2018; 5:46-55. [PMID: 29479564 PMCID: PMC5822730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The di-heme enzyme, MauG, utilizes a high-valent, charge-resonance stabilized bis-Fe(IV) state to perform protein radical-based catalytic chemistry. Though the bis-Fe(IV) species is able to oxidize remote tryptophan residues on its substrate protein, it does not rapidly oxidize its own residues in the absence of substrate. The slow return of bis-Fe(IV) MauG to its resting di-ferric state occurs via up to two intermediates, one of which has been previously proposed by Ma et al. (Biochem J 2016; 473:1769) to be a methionine-based radical in a recent study. In this work, we pursue intermediates involved in the return of high-valent MauG to its resting state in the absence of the substrate by EPR spectroscopy and radical trapping. The bis-Fe(IV) MauG is shown by EPR, HPLC, UV-Vis, and high-resolution mass spectrometry to oxidize the trapping agent, 5,5-dimethyl-1-pyrroline N-oxide (DMPO) to a radical species directly. Nitrosobenzene was also employed as a trapping agent and was shown to form an adduct with high-valent MauG species. The effects of DMPO and nitrosobenzene on the kinetics of the return to di-ferric MauG were both investigated. This work eliminates the possibility that a MauG-based methionine radical species accumulates during the self-reduction of bis-Fe(IV) MauG.
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Affiliation(s)
- Ian Davis
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
| | - Teruaki Koto
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Aimin Liu
- Department of Chemistry, University of Texas at San Antonio, San Antonio, TX 78249, USA
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA
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10
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Abstract
![]()
Electron-transfer kinetics have been
measured in four conjugates
of cytochrome P450 with surface-bound Ru-photosensitizers. The conjugates
are constructed with enzymes from Bacillus megaterium (CYP102A1) and Sulfolobus acidocaldarius (CYP119).
A W96 residue lies in the path between Ru and the heme in CYP102A1,
whereas H76 is present at the analogous location in CYP119. Two additional
conjugates have been prepared with (CYP102A1)W96H and (CYP119)H76W
mutant enzymes. Heme oxidation by photochemically generated Ru3+ leads to P450 compound II formation when a tryptophan residue
is in the path between Ru and the heme; no heme oxidation is observed
when histidine occupies this position. The data indicate that heme
oxidation proceeds via two-step tunneling through a tryptophan radical
intermediate. In contrast, heme reduction by photochemically generated
Ru+ proceeds in a single electron tunneling step with closely
similar rate constants for all four conjugates.
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Affiliation(s)
- Maraia E Ener
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Harry B Gray
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
| | - Jay R Winkler
- Beckman Institute, California Institute of Technology , Pasadena, California 91125, United States
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11
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12
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Köchling T, Morozova OB, Yurkovskaya AV, Vieth HM. Magnetic Resonance Characterization of One-Electron Oxidized Cyclic Dipeptides with Thioether Groups. J Phys Chem B 2016; 120:9277-86. [DOI: 10.1021/acs.jpcb.6b05442] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Talea Köchling
- Institut
für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
| | - Olga B. Morozova
- International Tomography Center, Institutskaya
3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova
2, 630090 Novosibirsk, Russia
| | - Alexandra V. Yurkovskaya
- International Tomography Center, Institutskaya
3a, 630090 Novosibirsk, Russia
- Novosibirsk State University, Pirogova
2, 630090 Novosibirsk, Russia
| | - Hans-Martin Vieth
- Institut
für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Germany
- International Tomography Center, Institutskaya
3a, 630090 Novosibirsk, Russia
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13
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Morozova OB, Panov MS, Vieth HM, Yurkovskaya AV. CIDNP study of sensitized photooxidation of S-methylcysteine and S-methylglutathione in aqueous solution. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2016.01.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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14
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Ignasiak MT, Pedzinski T, Rusconi F, Filipiak P, Bobrowski K, Houée-Levin C, Marciniak B. Photosensitized oxidation of methionine-containing dipeptides. From the transients to the final products. J Phys Chem B 2014; 118:8549-58. [PMID: 24946261 DOI: 10.1021/jp5039305] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Met residue oxidation has been studied for decades. Although many efforts have been made on the identification of free radicals, some doubts remain about their final fates, i.e., the nature of stable oxidation products. The photosensitized oxidation processes of two peptides, methionyl lysine (Met-Lys) and lysyl methionine (Lys-Met), were investigated using 3-carboxybenzophenone (3CB) as a sensitizer. Therefore, not only the transients were characterized but also the final products (by high-performance liquid chromatography and mass spectrometry) together with the quantum yields. As for the transients, the sulfur radical cations stabilized by a two-center three electron bonds with a nitrogen (S.·.N)(+) were identified in the case of Met-Lys. On the other hand, in Lys-Met, the intermolecular (S.·.S)(+) radical cations were found. The peptide-3CB adduct was the only stable product detected and was accompanied neither by sulfoxide formation nor by decarboxylation. It shows that both (S.·.N)(+) and (S.·.S)(+) radicals are converted into the relatively long-lived α-(alkylthio)alkyl radicals, which add to the 3CB-derived radicals. This addition reaction prevented all other oxidation processes such as formation of sulfoxide. The lysine residue was totally protected, which may also be of importance in biological processes.
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Affiliation(s)
- Marta T Ignasiak
- Faculty of Chemistry, Adam Mickiewicz University , Umultowska 89b, 61614 Poznan, Poland
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15
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Hendon CH, Carbery DR, Walsh A. Three-electron two-centred bonds and the stabilisation of cationic sulfur radicals. Chem Sci 2014. [DOI: 10.1039/c3sc53432d] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Spin stabilisation of conjugated motifs and heteroatoms suggests that the primary mechanism for cationic thioether stabilisation is not three-electron two-centred bonds.
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Affiliation(s)
| | | | - Aron Walsh
- Department of Chemistry
- University of Bath
- Bath, UK
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16
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Filipiak P, Hug GL, Bobrowski K, Pedzinski T, Kozubek H, Marciniak B. Sensitized photooxidation of s-methylglutathione in aqueous solution: intramolecular (S∴O) and (S∴N) bonded species. J Phys Chem B 2013; 117:2359-68. [PMID: 23347005 DOI: 10.1021/jp312184e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nanosecond laser flash photolysis was used to generate sulfur radical cations of the thioether, S-methylglutathione (S-Me-Glu), via the one-electron oxidation of this thioether by triplet 4-carboxybenzophenone. The purpose of this investigation was to follow the neighboring group effects resulting from the interactions between the sulfur radical cationic sites and nearby lone-pair electrons on heteroatoms within the radical cation, especially the electron lone-pairs on heteroatoms in the peptide bonds. The tripeptide, S-Me-Glu, offers several possible competing neighboring group effects that are characterized in this work. Quantum yields of the various radicals and three-electron bonded (both intramolecular and intermolecular) species were determined. The pH dependence of photoinduced decarboxylation yields was used as evidence for the identification of a nine-membered ring, sulfur-nitrogen, three-electron bonded species. The mechanisms of the secondary reactions of the radicals and radical cations were characterized by resolving their overlapping transient-absorption spectra and following their kinetic behavior. In particular, sulfur-oxygen and sulfur-nitrogen three-electron bonded species were identified where the oxygen and nitrogen atoms were in the peptide bonds.
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Affiliation(s)
- Piotr Filipiak
- Faculty of Chemistry, Adam Mickiewicz University, 61-614 Poznan, Poland.
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17
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Time-Resolved Electron Paramagnetic Resonance Spectroscopy. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2013. [DOI: 10.1016/b978-0-12-407754-6.00001-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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18
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Bhattacharya A, Bernstein ER. Influence of Turn (or Fold) and Local Charge in Fragmentation of the Peptide Analogue Molecule CH3CO-Gly-NH2 Following Single-Photon VUV (118.22 nm) Ionization. J Phys Chem A 2011; 115:10679-88. [DOI: 10.1021/jp203909y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atanu Bhattacharya
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Elliot R. Bernstein
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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19
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Abstract
Photo-induced damage to proteins occurs via multiple pathways. Direct damage induced by UVB (λ 280-320 nm) and UVA radiation (λ 320-400 nm) is limited to a small number of amino acid residues, principally tryptophan (Trp), tyrosine (Tyr), histidine (His) and disulfide (cystine) residues, with this occurring via both excited state species and radicals. Indirect protein damage can occur via singlet oxygen ((1)O(2)(1)Δ(g)), with this resulting in damage to Trp, Tyr, His, cystine, cysteine (Cys) and methionine (Met) residues. Although initial damage is limited to these residues multiple secondary processes, that occur both during and after radiation exposure, can result in damage to other intra- and inter-molecular sites. Secondary damage can arise via radicals (e.g. Trp, Tyr and Cys radicals), from reactive intermediates generated by (1)O(2) (e.g. Trp, Tyr and His peroxides) and via molecular reactions of photo-products (e.g. reactive carbonyls). These processes can result in protein fragmentation, aggregation, altered physical and chemical properties (e.g. hydrophobicity and charge) and modulated biological turnover. Accumulating evidence implicates these events in cellular and tissue dysfunction (e.g. apoptosis, necrosis and altered cell signaling), and multiple human pathologies.
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Affiliation(s)
- David I Pattison
- The Heart Research Institute, 7 Eliza Street, Newtown, Sydney, NSW 2042, Australia
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Bhattacharya A, Shin JW, Clawson KJ, Bernstein ER. Conformation specific and charge directed reactivity of radical cation intermediates of α-substituted (amino, hydroxy, and keto) bioactive carboxylic acids. Phys Chem Chem Phys 2010; 12:9700-12. [DOI: 10.1039/c003416a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Morozova OB, Korchak SE, Vieth HM, Yurkovskaya AV. Photo-CIDNP Study of Transient Radicals of Met-Gly and Gly-Met Peptides in Aqueous Solution at Variable pH. J Phys Chem B 2009; 113:7398-406. [DOI: 10.1021/jp8112182] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Olga B. Morozova
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
| | - Sergey E. Korchak
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
| | - Hans-Martin Vieth
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
| | - Alexandra V. Yurkovskaya
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia, Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, D-14195, Germany
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Photophysics of ruthenium(II) complexes carrying amino acids in the ligand 2,2′-bipyridine and intramolecular electron transfer from methionine to photogenerated Ru(III). Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Zhao J, Ng CMD, Chu IK, Siu KWM, Hopkinson AC. Methionine, α-methylmethionine and S-methylcysteine radical cations: generations and dissociations in the gas phase. Phys Chem Chem Phys 2009; 11:7629-39. [DOI: 10.1039/b905615g] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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White RC, Gorelik V, Bagryanskaya EG, Forbes MDE. Photoredox chemistry of AOT: electron transfer and hydrogen abstraction in microemulsions involving the surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:4183-91. [PMID: 17343399 DOI: 10.1021/la063322a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Time-resolved magnetic resonance experiments (TREPR and CIDNP) are used to investigate previously unobserved redox chemistry of the surfactant dioctyl sulfosuccinate ester (AOT) using the photoexcited triplet state of anthraquinone 2,6-disulfonate (3AQDS*). Several different free radicals resulting from two independent oxidation pathways (electron transfer and hydrogen abstraction) are observed. These include the radical ions of AQDS and sulfite from electron-transfer processes, carbon-centered radicals from H-atom abstraction reactions, and an additional carbon-centered radical formed by electron transfer from the AOT sulfonate head group followed by the loss of SO3. The radicals exhibit intense chemically induced dynamic electron spin polarization (CIDEP) in their TREPR spectra. The intensity ratios of the observed TREPR signals for each radical depend on the water pool size and temperature, which in turn affect the predominant CIDEP mechanism. All signal carriers are accounted for by simulation, and CIDNP results provide strong supporting evidence for the assignments.
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Affiliation(s)
- Ryan C White
- Caudill Laboratories, CB#3290, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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25
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Fourré I, Silvi B. What can we learn from two-center three-electron bonding with the topological analysis of ELF? HETEROATOM CHEMISTRY 2007. [DOI: 10.1002/hc.20325] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Huvaere K, Andersen ML, Storme M, Van Bocxlaer J, Skibsted LH, De Keukeleire D. Flavin-induced photodecomposition of sulfur-containing amino acids is decisive in the formation of beer lightstruck flavor. Photochem Photobiol Sci 2006; 5:961-9. [PMID: 17019476 DOI: 10.1039/b609337j] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photooxidation of sulfur-containing amino acids and derivatives readily occurs upon visible-light irradiation in the presence of flavins. The sulfur moiety seems pivotal for interaction, as was determined from kinetic analyses using laser flash photolysis spectroscopy. After photooxidation, the resulting radical intermediates were characterized by addition to a spin trap, followed by electron paramagnetic resonance spectroscopy and evaluation of the coupling constants. The presence of the proposed radical intermediates was strongly supported by the identification of the reaction products using mass spectrometry. Accordingly, feasible degradation pathways for various sulfur-containing amino acids and derivatives were proposed. It was finally proven that flavin-induced photoproduction of sulfhydryl radicals and recombination with a 3-methylbut-2-enyl radical, derived from the photodegradation of hop-derived isohumulones, are decisive in the formation of beer lightstruck flavor.
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Affiliation(s)
- Kevin Huvaere
- Ghent University, Faculty of Pharmaceutical Sciences, Laboratory of Pharmacognosy and Phytochemistry, Harelbekestraat 72, B-9000, Ghent, Belgium
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Morozova OB, Korchak SE, Sagdeev RZ, Yurkovskaya AV. Time-Resolved Chemically Induced Dynamic Nuclear Polarization Studies of Structure and Reactivity of Methionine Radical Cations in Aqueous Solution as a Function of pH. J Phys Chem A 2005; 109:10459-66. [PMID: 16833344 DOI: 10.1021/jp054002n] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using time-resolved chemically induced dynamic nuclear polarization (CIDNP) techniques, we have studied the mechanism of the photoreactions of triplet excited 4-carboxybenzophenone (CBP) with l-methionine (Met) and 3-(methylthio)propylamine (MTPA) in aqueous solution and the details of the formation of CIDNP at pH from 6.7 to 13.6. At a pH below the pKa of the nitrogen atom of Met, the CIDNP is strongly affected by degenerate electron exchange between the S-S cationic radical dimer and the zwitterionic form of Met with the rate constant kex = 3.4 x 10(8) s(-1) providing an exhaustive explanation of the pH dependence of steady-state CIDNP that was previously interpreted as a manifestation of fast interconversion among three different methionine radical species (Goez, M.; Rozwadowski, J. J. Phys. Chem. A 1998, 102, 7945-7953). By analyzing the polarization of different protons formed in geminate recombination as a function of the pH, we obtained the branching ratio between two reaction pathways for oxidative quenching of (T)CBP via electron transfer from the sulfur and nitrogen atoms of Met and MTPA. Nuclear spin-lattice relaxation times were determined in the dimeric cation radical of Met (T1,S = 8.5 micros). In the cyclic radical cation of MTPA with a three-electron two-center S-N bond, the estimated paramagnetic relaxation is comparatively slow for all protons. Fast deprotonation of the primary aminium radical cation of MTPA and Met in strongly basic solution takes place on the submicrosecond time scale leading to efficient formation of CIDNP in the neutral aminyl radical.
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Affiliation(s)
- Olga B Morozova
- International Tomography Center, Institutskaya 3a, 630090 Novosibirsk-90, Russia
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