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De Jesus IS, Vélez JAC, Pissinati EF, Correia JTM, Rivera DG, Paixao MW. Recent Advances in Photoinduced Modification of Amino Acids, Peptides, and Proteins. CHEM REC 2024; 24:e202300322. [PMID: 38279622 DOI: 10.1002/tcr.202300322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/01/2023] [Indexed: 01/28/2024]
Abstract
The chemical modification of biopolymers like peptides and proteins is a key technology to access vaccines and pharmaceuticals. Similarly, the tunable derivatization of individual amino acids is important as they are key building blocks of biomolecules, bioactive natural products, synthetic polymers, and innovative materials. The high diversity of functional groups present in amino acid-based molecules represents a significant challenge for their selective derivatization Recently, visible light-mediated transformations have emerged as a powerful strategy for achieving chemoselective biomolecule modification. This technique offers numerous advantages over other methods, including a higher selectivity, mild reaction conditions and high functional-group tolerance. This review provides an overview of the most recent methods covering the photoinduced modification for single amino acids and site-selective functionalization in peptides and proteins under mild and even biocompatible conditions. Future challenges and perspectives are discussed beyond the diverse types of photocatalytic transformations that are currently available.
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Affiliation(s)
- Iva S De Jesus
- Laboratory for Sustainable Organic Synthesis and Catalysis, Department of Chemistry, Federal University of São Carlos - UFSCar, São Carlos, São Paulo, 13565-905, Brazil
| | - Jeimy A C Vélez
- Laboratory for Sustainable Organic Synthesis and Catalysis, Department of Chemistry, Federal University of São Carlos - UFSCar, São Carlos, São Paulo, 13565-905, Brazil
| | - Emanuele F Pissinati
- Laboratory for Sustainable Organic Synthesis and Catalysis, Department of Chemistry, Federal University of São Carlos - UFSCar, São Carlos, São Paulo, 13565-905, Brazil
| | - Jose Tiago M Correia
- Laboratory for Sustainable Organic Synthesis and Catalysis, Department of Chemistry, Federal University of São Carlos - UFSCar, São Carlos, São Paulo, 13565-905, Brazil
| | - Daniel G Rivera
- Laboratory of Synthetic and Biomolecular Chemistry, Faculty of Chemistry, University of Havana Zapata & G, Havana, 10400, Cuba
| | - Márcio W Paixao
- Laboratory for Sustainable Organic Synthesis and Catalysis, Department of Chemistry, Federal University of São Carlos - UFSCar, São Carlos, São Paulo, 13565-905, Brazil
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2
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Ignasiak-Kciuk M, Nowicka-Bauer K, Grzechowiak M, Ravnsborg T, Frąckowiak K, Jensen ON, Jaskólski M, Marciniak B. Does the presence of ground state complex between a PR-10 protein and a sensitizer affect the mechanism of sensitized photo-oxidation? Free Radic Biol Med 2023; 198:27-43. [PMID: 36738800 DOI: 10.1016/j.freeradbiomed.2023.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/12/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
The mechanisms of one-electron protein oxidation are complicated and still not well-understood. In this work, we investigated the reaction of sensitized photo-oxidation using carboxybenzophenone (CB) as a sensitizer and a PR-10 protein (MtN13) as a quencher, which is intrinsically complicated due to the complex structure of the protein and multiple possibilities of CB attack. To predict and examine the possible reactions precisely, the 3D structure of the MtN13 protein was taken into account. Our crystallographic studies revealed a specific binding of the CB molecule in the protein's hydrophobic cavity, while mass spectrometry identified the amino acid residues (Met, Tyr, Asp and Phe) creating adducts with the sensitizer, thus indicating the sites of 3CB* quenching. In addition, protein aggregation was also observed. The detailed mechanisms of CB quenching by the MtN13 molecule were elucidated by an analysis of transient products by means of time-resolved spectroscopy. The investigation of the transient and stable products formed during the protein photo-oxidation was based on the data obtained from HPLC-MS analysis of model compounds, single amino acids and dipeptides. Our proposed mechanisms of sensitized protein photo-oxidation emphasize the role of a ground state complex between the protein and the sensitizer and indicate several new and specific products arising as a result of one-electron oxidation. Based on the analysis of the transient and stable products, we have demonstrated the influence of neighboring groups, especially in the case of Tyr oxidation, where the tyrosyl radical can be formed via a direct electron transfer from Tyr to CB* or via an intramolecular electron transfer from Tyr to Met radical cation Met > S●+ or thiyl radical CysS● from neighboring oxidized groups.
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Affiliation(s)
- Marta Ignasiak-Kciuk
- Center for Advanced Technology, Adam Mickiewicz University, Poznan, Poland; Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland.
| | | | - Marta Grzechowiak
- Institute of Bioorganic Chemistry, Polish Academy of Science, Poznan, Poland
| | - Tina Ravnsborg
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Kamil Frąckowiak
- Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland
| | - Ole N Jensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Mariusz Jaskólski
- Institute of Bioorganic Chemistry, Polish Academy of Science, Poznan, Poland; Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland
| | - Bronisław Marciniak
- Center for Advanced Technology, Adam Mickiewicz University, Poznan, Poland; Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland
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3
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On the electrochemical oxidation of methionine residues of proteins. J Electroanal Chem (Lausanne) 2023. [DOI: 10.1016/j.jelechem.2023.117209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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4
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Hybrid Nanoparticles Based on Cobalt Ferrite and Gold: Preparation and Characterization. METALS 2021. [DOI: 10.3390/met11050705] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
During the past few decades, hybrid nanoparticles (HNPs) based on a magnetic material and gold have attracted interest for applications in catalysis, diagnostics and nanomedicine. In this paper, magnetic CoFe2O4/Au HNPs with an average particle size of 20 nm, decorated with 2 nm gold clusters, were prepared using methionine as a reducer and an anchor between CoFe2O4 and gold. The methionine was used to grow the Au clusters to a solid gold shell (up to 10 gold deposition cycles). The obtained nanoparticles (NPs) were studied by X-Ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, X-Ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy techniques. The TEM images of the obtained HNPs showed that the surface of cobalt ferrite was covered with gold nanoclusters, the size of which slightly increased with an increase in the number of gold deposition cycles (from 2.12 ± 0.15 nm after 1 cycle to 2.46 ± 0.13 nm after 10 cycles). The density of the Au clusters on the cobalt ferrite surface insignificantly decreased during repeated stages of gold deposition: 21.4 ± 2.7 Au NPs/CoFe2O4 NP after 1 cycle, 19.0 ± 1.2 after 6 cycles and 18.0 ± 1.4 after 10 cycles. The magnetic measurements showed that the obtained HNPs possessed typical ferrimagnetic behavior, which corresponds to that of CoFe2O4 nanoparticles. The toxicity evaluation of the synthesized HNPs on Chlorella vulgaris indicated that they can be applied to biomedical applications such as magnetic hyperthermia, photothermal therapy, drug delivery, bioimaging and biosensing.
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Kim J, Li BX, Huang RYC, Qiao JX, Ewing WR, MacMillan DWC. Site-Selective Functionalization of Methionine Residues via Photoredox Catalysis. J Am Chem Soc 2020; 142:21260-21266. [PMID: 33290649 DOI: 10.1021/jacs.0c09926] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bioconjugation technologies have revolutionized the practice of biology and medicine by allowing access to novel biomolecular scaffolds. New methods for residue-selective bioconjugation are highly sought to expand the toolbox for a variety of bioconjugation applications. Herein we report a site-selective methionine bioconjugation protocol that uses photoexcited lumiflavin to generate open-shell intermediates. This reduction-potential-gated strategy enables access to residues unavailable with traditional nucleophilicity-based conjugation methods. To demonstrate the versatility and robustness of this new protocol, we have modified various proteins and further utilized this functional handle to append diverse biological payloads.
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Affiliation(s)
- Junyong Kim
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - Beryl X Li
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
| | - Richard Y-C Huang
- Pharmaceutical Candidate Optimization, Research and Development, Bristol-Myers Squibb Company, Princeton, New Jersey 08542, United States
| | - Jennifer X Qiao
- Discovery Chemistry, Research and Development, Bristol-Myers Squibb Company, Princeton, New Jersey 08542, United States
| | - William R Ewing
- Discovery Chemistry, Research and Development, Bristol-Myers Squibb Company, Princeton, New Jersey 08542, United States
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, New Jersey 08544, United States
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Kanmaz N, Uzer A, Hizal J, Apak R. Determination of total antioxidant capacity of Cynara Scolymus L. (globe artichoke) by using novel nanoparticle-based ferricyanide/Prussian blue assay. Talanta 2020; 216:120960. [PMID: 32456941 DOI: 10.1016/j.talanta.2020.120960] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 01/02/2023]
Abstract
A novel ferricyanide/Prussian blue (PB) assay for total antioxidant capacity (TAC) determination was developed exploiting the formation of PB nanoparticles in the presence of polyvinylpyrrolidone (PVP) as stabilizer. This improved method, named as "nanoparticle-based ferricyanide/Prussian blue assay (PBNP)", was applied to the TAC measurement of Cynara Scolymus L. (globe artichoke). The calibration results of the novel (PBNP) method were compared with those of a similar nanoparticle PB method performed in the absence of PVP, and of a sodium dodecyl sulfate-modified and acid-optimized ferricyanide reference assay. Compared to similar common Fe(III)-based TAC assays, much higher molar absorptivities, pointing out higher response to different kinds of antioxidants, were obtained with PBNP for all tested antioxidants, and lower LOD and LOQ values were achieved for thiols. As an additional advantage, methionine, not responding to other electron-transfer based TAC reagents, could be measured. PBNP could detect various antioxidants with one-two orders-of-magnitude lower LOD values than those of widely used TAC assays like CUPRAC and Folin-Ciocalteau well correlating with the proposed assay.
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Affiliation(s)
- Nergiz Kanmaz
- Yalova University, Engineering Faculty, Chemical and Process Engineering Department, 77100, Yalova, Turkey
| | - Ayşem Uzer
- Istanbul University-Cerrahpasa, Engineering Faculty, Chemistry Department, Avcilar, 34320, Istanbul, Turkey
| | - Jülide Hizal
- Yalova University, Engineering Faculty, Chemical and Process Engineering Department, 77100, Yalova, Turkey.
| | - Resat Apak
- Istanbul University-Cerrahpasa, Engineering Faculty, Chemistry Department, Avcilar, 34320, Istanbul, Turkey; Turkish Academy of Sciences (TUBA), Piyade Sokak No: 27, Cankaya, 06690, Ankara, Turkey
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Abstract
In this study, NiFe2O4@Au core–shell nanoparticles were prepared by the direct reduction of gold on the magnetic surface using amino acid methionine as a reducer and a stabilizing agent simultaneously. The obtained nanoparticles after three steps of gold deposition had an average size of about 120 nm. The analysis of particles was performed by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy techniques. The results indicate successful synthesis of core–shell particles with the magnetic core, which consists of a few agglomerated nickel ferrite crystals with an average size 25.2 ± 2.0 nm, and the thick gold shell consists of fused Au0 nanoparticles (NPs). Magnetic properties of the obtained nanoparticles were examined with magnetic circular dichroism. It was shown that the magnetic behavior of NiFe2O4@Au NPs is typical for superparamagnetic NPs and corresponds to that for NiFe2O4 NPs without a gold shell. The results indicate the successful synthesis of core–shell particles with the magnetic nickel ferrite core and thick gold shell, and open the potential for the application of the investigated hybrid nanoparticles in hyperthermia, targeted drug delivery, magnetic resonance imaging, or cell separation. The developed synthesis strategy can be extended to other metal ferrites and iron oxides.
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Hesabi N, Ebrahimi A. The electrochemical properties and PIM1 kinase enzyme inhibition of some 2-(hydroxy phenyl amino) naphthalene-1,4-dione derivatives. J Mol Liq 2020. [DOI: 10.1016/j.molliq.2020.112874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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9
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•OH oxidation of methionine in the presence of discrete water molecules: DFT, QTAIM and valence bond analyses. Struct Chem 2019. [DOI: 10.1007/s11224-019-01438-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Affiliation(s)
- Michael Hellwig
- Professur für LebensmittechemieTechnische Universität Dresden D-01062 Dresden Deutschland
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11
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Abstract
Oxidation is one of the deterioration reactions of proteins in food, the importance of which is comparable to others such as Maillard, lipation, or protein-phenol reactions. While research on protein oxidation has led to a precise understanding of the processes and consequences in physiological systems, knowledge about the specific effects of protein oxidation in food or the role of "oxidized" dietary protein for the human body is comparatively scarce. Food protein oxidation can occur during the whole processing axis, from primary production to intestinal digestion. The present review summarizes the current knowledge and mechanisms of food protein oxidation from a chemical, technological, and nutritional-physiological viewpoint and gives a comprehensive classification of the individual reactions. Different analytical approaches are compared, and the relationship between oxidation of food proteins and oxidative stress in vivo is critically evaluated.
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Affiliation(s)
- Michael Hellwig
- Chair of Food Chemistry, Technische Universität Dresden, D-01062, Dresden, Germany
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12
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Calhoun SE, Meunier CJ, Lee CA, McCarty GS, Sombers LA. Characterization of a Multiple-Scan-Rate Voltammetric Waveform for Real-Time Detection of Met-Enkephalin. ACS Chem Neurosci 2019; 10:2022-2032. [PMID: 30571911 PMCID: PMC6473485 DOI: 10.1021/acschemneuro.8b00351] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 12/20/2018] [Indexed: 02/07/2023] Open
Abstract
Opioid peptides are critically involved in a variety of physiological functions necessary for adaptation and survival, and as such, understanding the precise actions of endogenous opioid peptides will aid in identification of potential therapeutic strategies to treat a variety of disorders. However, few analytical tools are currently available that offer both the sensitivity and spatial resolution required to monitor peptidergic concentration fluctuations in situ on a time scale commensurate with that of neuronal communication. Our group has developed a multiple-scan-rate waveform to enable real-time voltammetric detection of tyrosine containing neuropeptides. Herein, we have evaluated the waveform parameters to increase sensitivity to methionine-enkephalin (M-ENK), an endogenous opioid neuropeptide implicated in pain, stress, and reward circuits. M-ENK dynamics were monitored in adrenal gland tissue, as well as in the dorsal striatum of anesthetized and freely behaving animals. The data reveal cofluctuations of catecholamine and M-ENK in both locations and provide measurements of M-ENK dynamics in the brain with subsecond temporal resolution. Importantly, this work also demonstrates how voltammetric waveforms can be customized to enhance detection of specific target analytes, broadly speaking.
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Affiliation(s)
- S. E. Calhoun
- Department of Chemistry, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - C. J. Meunier
- Department of Chemistry, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - C. A. Lee
- Department of Chemistry, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - G. S. McCarty
- Department of Chemistry, North
Carolina State University, Raleigh, North Carolina 27695, United States
| | - L. A. Sombers
- Department of Chemistry, North
Carolina State University, Raleigh, North Carolina 27695, United States
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13
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Crespo M, Font-Bardia M, Hamidizadeh P, Martínez M, Nabavizadeh SM. Kinetico-mechanistic study on the reduction/complexation sequence of PtIV/PtII organometallic complexes by thiol-containing biological molecules. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.10.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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14
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Bottecchia C, Noël T. Photocatalytic Modification of Amino Acids, Peptides, and Proteins. Chemistry 2018; 25:26-42. [PMID: 30063101 PMCID: PMC6348373 DOI: 10.1002/chem.201803074] [Citation(s) in RCA: 128] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/27/2018] [Indexed: 02/06/2023]
Abstract
In the last decade, visible‐light photoredox catalysis has emerged as a powerful strategy to enable novel transformations in organic synthesis. Owing to mild reaction conditions (i.e., room temperature, use of visible light) and high functional‐group tolerance, photoredox catalysis could represent an ideal strategy for chemoselective biomolecule modification. Indeed, a recent trend in photoredox catalysis is its application to the development of novel methodologies for amino acid modification. Herein, an up‐to‐date overview of photocatalytic methodologies for the modification of single amino acids, peptides, and proteins is provided. The advantages offered by photoredox catalysis and its suitability in the development of novel biocompatible methodologies are described. In addition, a brief consideration of the current limitations of photocatalytic approaches, as well as future challenges to be addressed, are discussed.
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Affiliation(s)
- Cecilia Bottecchia
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology, De Rondom 70 (STO 1.37), 5612 AP, Eindhoven, The Netherlands
| | - Timothy Noël
- Department of Chemical Engineering and Chemistry, Micro Flow Chemistry and Process Technology, Eindhoven University of Technology, De Rondom 70 (STO 1.37), 5612 AP, Eindhoven, The Netherlands
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15
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Sulfur Radicals and Their Application. Top Curr Chem (Cham) 2018; 376:22. [DOI: 10.1007/s41061-018-0197-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/11/2018] [Indexed: 12/11/2022]
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16
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Close DM, Wardman P. Calculation of Standard Reduction Potentials of Amino Acid Radicals and the Effects of Water and Incorporation into Peptides. J Phys Chem A 2017; 122:439-445. [PMID: 29219315 DOI: 10.1021/acs.jpca.7b10766] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Guanine (Guo) is generally accepted as the most easily oxidized DNA base when cells are subjected to ionizing radiation; calculations of the standard reduction potential of the guanyl radical, Eo(Guo•+/Guo) are within ∼0.1 V of experimental values in aqueous solution extrapolated to standard conditions. While a number of experimental studies have shown some amino acid radicals have redox properties at pH 7 which suggest or confirm a capacity for radical "repair" by electron transfer from the amino acid to Guo•+ (or its deprotonated conjugate), the redox properties of the radicals of other amino acids, including methionine, lysine and cystine, are less well characterized. In addition, the effects of incorporation of the amino acids into peptides, or the effects of water of hydration on calculated potentials, have not been extensively studied. In this work, calculations of standard reduction potentials of radicals from model amino acids as they appear in histone proteins are performed. To predict redox properties at pH 7, acid dissociation constants (pKas) of both radical and ground state amino acids are required. In some instances these are not experimentally determined and calculated pKas have been derived for some common amino acids and compared with experimental values.
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Affiliation(s)
- David M Close
- Department of Physics, East Tennessee State University , Johnson City, Tennessee 37614, United States
| | - Peter Wardman
- Gray Cancer Institute, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford , Oxford OX3 7DQ, U.K
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17
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Intermolecular hydrogen bonds between 1,4-benzoquinones and HF molecule: Synergetic effects, reduction potentials and electron affinities. J Mol Graph Model 2017; 77:86-93. [PMID: 28850896 DOI: 10.1016/j.jmgm.2017.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/10/2017] [Accepted: 08/11/2017] [Indexed: 11/20/2022]
Abstract
Some biological activities of quinones can be attributed to the H-bonding ability of acceptor oxygen atoms. According to the results obtained from the quantum mechanical calculations performed on a wide variety of complexes between the 1,4-benzoquinone (BQ) derivatives and HF molecules, the interplay between H-bonds and individual H-bond interaction energies (EHB) can be affected by the substituents placed on the six-membered ring of BQ. The total binding energies of complexes become more negative by the electron donating substituents (EDSs) while the changes are reversed by the electron withdrawing substituents (EWSs). The mutual interplay between the X-BQ⋯(HF)n (n=1-3) interactions has been investigated using the geometrical parameters, synergetic energies (SE) and the EHB values. Hydrogen bonding decreases the reduction potentials (E0red) and increases the electron affinities (EA) of X-BQ derivatives. Linear relationships have been observed between the E0red (and EA) values and the Hammett constants of substituents.
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18
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Scuderi D, Bergès J, de Oliveira P, Houée-Levin C. Methionine one-electron oxidation: Coherent contributions from radiolysis, IRMPD spectroscopy, DFT calculations and electrochemistry. Radiat Phys Chem Oxf Engl 1993 2016. [DOI: 10.1016/j.radphyschem.2016.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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19
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Archirel P, Bergès J, Houée-Lévin C. Radical Cations of the Monomer and van der Waals Dimer of a Methionine Residue as Prototypes of (2 Center–3 Electron) SN and SS Bonds. Molecular Simulations of Their Absorption Spectra in Water. J Phys Chem B 2016; 120:9875-86. [DOI: 10.1021/acs.jpcb.6b06329] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Pierre Archirel
- Laboratoire
de Chimie Physique, CNRS, UMR 8000, Université Paris-Sud, F91405 Orsay, France
| | - Jacqueline Bergès
- Laboratoire
de Chimie Théorique, UPMC Univ Paris 06, CNRS, UMR 7616, Sorbonne Universités, CC 137-4, place Jussieu, F75252 Paris Cedex 05, France
| | - Chantal Houée-Lévin
- Laboratoire
de Chimie Physique, CNRS, UMR 8000, Université Paris-Sud, F91405 Orsay, France
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20
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Filipiak P, Bobrowski K, Hug GL, Pogocki D, Schöneich C, Marciniak B. Formation of a Three-Electron Sulfur–Sulfur Bond as a Probe for Interaction between Side Chains of Methionine Residues. J Phys Chem B 2016; 120:9732-44. [DOI: 10.1021/acs.jpcb.6b06494] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Piotr Filipiak
- Faculty
of Chemistry, Adam Mickiewicz University, 61-614 Poznan, Poland
| | - Krzysztof Bobrowski
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland
- Radiation
Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Gordon L. Hug
- Faculty
of Chemistry, Adam Mickiewicz University, 61-614 Poznan, Poland
- Radiation
Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Dariusz Pogocki
- Faculty
of Biology and Agriculture, University of Rzeszow, 35-601 Rzeszow, Poland
| | - Christian Schöneich
- School
of Pharmacy, Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, United States
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21
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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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22
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Scuderi D, Ignasiak MT, Serfaty X, de Oliveira P, Houée Levin C. Tandem mass spectrometry and infrared spectroscopy as a tool to identify peptide oxidized residues. Phys Chem Chem Phys 2016; 17:25998-6007. [PMID: 26292724 DOI: 10.1039/c5cp03223g] [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
The final products obtained by the oxidation of small model peptides containing the thioether function, either methionine or S-methyl cysteine, have been characterized by tandem mass spectrometry and IR Multiple Photon Dissociation (IRMPD) spectroscopy. The modified positions have been clearly identified by the CID-MS(2) fragmentation mass spectra with or without loss of sulfenic acid, as well as by the vibrational signature of the sulfoxide bond at around 1000 cm(-1). The oxidation of the thioether function did not lead to the same products in these model peptides. The sulfoxide and sulfone (to a lesser extent) have been clearly identified as final products of the oxidation of S-methyl-glutathione (GS-Me). Decarboxylation or hydrogen loss are the major oxidation pathways in GS-Me, while they have not been observed in tryptophan-methionine and methionine-tryptophan (Trp-Met and Met-Trp). Interestingly, tryptophan is oxidized in the dipeptide Met-Trp, while that is not the case in the reverse sequence (Trp-Met).
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Affiliation(s)
- D Scuderi
- Laboratoire de Chimie Physique, Université Paris Sud, 91405 Orsay Cedex, France.
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23
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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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24
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Uranga J, Mujika JI, Matxain JM. ·OH Oxidation Toward S- and OH-Containing Amino Acids. J Phys Chem B 2015; 119:15430-42. [DOI: 10.1021/acs.jpcb.5b09825] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jon Uranga
- Kimika Fakultatea,
Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International
Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
| | - Jon I. Mujika
- Kimika Fakultatea,
Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International
Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
| | - Jon M. Matxain
- Kimika Fakultatea,
Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International
Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi, Spain
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25
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Torkova A, Koroleva O, Khrameeva E, Fedorova T, Tsentalovich M. Structure-Functional Study of Tyrosine and Methionine Dipeptides: An Approach to Antioxidant Activity Prediction. Int J Mol Sci 2015; 16:25353-76. [PMID: 26512651 PMCID: PMC4632805 DOI: 10.3390/ijms161025353] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/10/2015] [Accepted: 10/08/2015] [Indexed: 02/07/2023] Open
Abstract
Quantum chemical methods allow screening and prediction of peptide antioxidant activity on the basis of known experimental data. It can be used to design the selective proteolysis of protein sources in order to obtain products with antioxidant activity. Molecular geometry and electronic descriptors of redox-active amino acids, as well as tyrosine and methionine-containing dipeptides, were studied by Density Functional Theory method. The calculated data was used to reveal several descriptors responsible for the antioxidant capacities of the model compounds based on their experimentally obtained antioxidant capacities against ABTS (2,2'-Azino-bis-(3-ethyl-benzothiazoline-6-sulfonate)) and peroxyl radical. A formula to predict antioxidant activity of peptides was proposed.
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Affiliation(s)
- Anna Torkova
- Bach Institute of Biochemistry of the Russian Academy of Sciences, Leninsky Prospekt, 33, bld 2, Moscow 119071, Russian.
| | - Olga Koroleva
- Bach Institute of Biochemistry of the Russian Academy of Sciences, Leninsky Prospekt, 33, bld 2, Moscow 119071, Russian.
| | - Ekaterina Khrameeva
- Department of Bioengineering and Bioinformatics, Moscow State University, GSP-1, Leninskie Hills, bld 73, Moscow 119234, Russian.
| | - Tatyana Fedorova
- Bach Institute of Biochemistry of the Russian Academy of Sciences, Leninsky Prospekt, 33, bld 2, Moscow 119071, Russian.
| | - Mikhail Tsentalovich
- Bach Institute of Biochemistry of the Russian Academy of Sciences, Leninsky Prospekt, 33, bld 2, Moscow 119071, Russian.
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26
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Gardner PR, Gardner DP, Gardner AP. Globins Scavenge Sulfur Trioxide Anion Radical. J Biol Chem 2015; 290:27204-27214. [PMID: 26381408 DOI: 10.1074/jbc.m115.679621] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Indexed: 01/16/2023] Open
Abstract
Ferrous myoglobin was oxidized by sulfur trioxide anion radical (STAR) during the free radical chain oxidation of sulfite. Oxidation was inhibited by the STAR scavenger GSH and by the heme ligand CO. Bimolecular rate constants for the reaction of STAR with several ferrous globins and biomolecules were determined by kinetic competition. Reaction rate constants for myoglobin, hemoglobin, neuroglobin, and flavohemoglobin are large at 38, 120, 2,600, and ≥ 7,500 × 10(6) m(-1) s(-1), respectively, and correlate with redox potentials. Measured rate constants for O2, GSH, ascorbate, and NAD(P)H are also large at ∼100, 10, 130, and 30 × 10(6) m(-1) s(-1), respectively, but nevertheless allow for favorable competition by globins and a capacity for STAR scavenging in vivo. Saccharomyces cerevisiae lacking sulfite oxidase and deleted of flavohemoglobin showed an O2-dependent growth impairment with nonfermentable substrates that was exacerbated by sulfide, a precursor to mitochondrial sulfite formation. Higher O2 exposures inactivated the superoxide-sensitive mitochondrial aconitase in cells, and hypoxia elicited both aconitase and NADP(+)-isocitrate dehydrogenase activity losses. Roles for STAR-derived peroxysulfate radical, superoxide radical, and sulfo-NAD(P) in the mechanism of STAR toxicity and flavohemoglobin protection in yeast are suggested.
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27
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Bergès J, Kamar A, de Oliveira P, Pilmé J, Luppi E, Houée-Levin C. Toward an Understanding of the Oxidation Process of Methionine Enkephalin: A Combined Electrochemistry, Quantum Chemistry and Quantum Chemical Topology Analysis. J Phys Chem B 2015; 119:6885-93. [DOI: 10.1021/acs.jpcb.5b01207] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jacqueline Bergès
- Laboratoire
de Chimie Théorique, Sorbonne Universités, UPMC Université Paris 06, UMR 7616 , F-75005 Paris, France
- CNRS UMR 7616, 4 Place Jussieu, 75252 Paris Cedex 5, France
| | - Amanda Kamar
- Laboratoire
de Chimie Physique, Université Paris-Sud, F-91405 Orsay, France
- CNRS, UMR 8000, F-91405 Orsay, France
| | - Pedro de Oliveira
- Laboratoire
de Chimie Physique, Université Paris-Sud, F-91405 Orsay, France
- CNRS, UMR 8000, F-91405 Orsay, France
| | - Julien Pilmé
- Laboratoire
de Chimie Théorique, Sorbonne Universités, UPMC Université Paris 06, UMR 7616 , F-75005 Paris, France
- CNRS UMR 7616, 4 Place Jussieu, 75252 Paris Cedex 5, France
| | - Eleonora Luppi
- Laboratoire
de Chimie Théorique, Sorbonne Universités, UPMC Université Paris 06, UMR 7616 , F-75005 Paris, France
- CNRS UMR 7616, 4 Place Jussieu, 75252 Paris Cedex 5, France
| | - Chantal Houée-Levin
- Laboratoire
de Chimie Physique, Université Paris-Sud, F-91405 Orsay, France
- CNRS, UMR 8000, F-91405 Orsay, France
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28
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Geng J, Davis I, Liu A. Probing bis-Fe(IV) MauG: experimental evidence for the long-range charge-resonance model. Angew Chem Int Ed Engl 2015; 54:3692-6. [PMID: 25631460 PMCID: PMC4363735 DOI: 10.1002/anie.201410247] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/14/2014] [Indexed: 11/08/2022]
Abstract
The biosynthesis of tryptophan tryptophylquinone, a protein-derived cofactor, involves a long-range reaction mediated by a bis-Fe(IV) intermediate of a diheme enzyme, MauG. Recently, a unique charge-resonance (CR) phenomenon was discovered in this intermediate, and a biological, long-distance CR model was proposed. This model suggests that the chemical nature of the bis-Fe(IV) species is not as simple as it appears; rather, it is composed of a collection of resonance structures in a dynamic equilibrium. Here, we experimentally evaluated the proposed CR model by introducing small molecules to, and measuring the temperature dependence of, bis-Fe(IV) MauG. Spectroscopic evidence was presented to demonstrate that the selected compounds increase the decay rate of the bis-Fe(IV) species by disrupting the equilibrium of the resonance structures that constitutes the proposed CR model. The results support this new CR model and bring a fresh concept to the classical CR theory.
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Affiliation(s)
- Jiafeng Geng
- Department of Chemistry and Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, Georgia, United States, Homepage: http://Feradical.gsu.edu
| | - Ian Davis
- Department of Chemistry and Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, Georgia, United States, Homepage: http://Feradical.gsu.edu
| | - Aimin Liu
- Department of Chemistry and Center for Diagnostics & Therapeutics, Georgia State University, Atlanta, Georgia, United States, Homepage: http://Feradical.gsu.edu
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29
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Wu H, Liu Y, Li M, Chong Y, Zeng M, Lo YM, Yin JJ. Size-dependent tuning of horseradish peroxidase bioreactivity by gold nanoparticles. NANOSCALE 2015; 7:4505-13. [PMID: 25684572 DOI: 10.1039/c4nr07056a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Molecules with diverse biological functions, such as heme peroxidases, can be useful tools for identifying potential biological effects of gold nanoparticles (AuNPs) at the molecular level. Here, using UV-Vis, circular dichroism, dynamic light scattering, and electron spin resonance spectroscopy, we report tuning of horseradish peroxidase (HRP) bioactivity by reactant-free AuNPs with diameters of 5, 10, 15, 30 and 60 nm (Au-5 nm, Au-10 nm, Au-15 nm, Au-30 nm and Au-60 nm). HRP conjugation to AuNPs was observed with only Au-5 nm and Au-10 nm prominently increasing the α-helicity of the enzyme to extents inversely related to their size. Au-5 nm inhibited both HRP peroxidase activity toward 3,3',5,5'-tetramethylbenzidine and HRP compound I/II reactivity toward 5,5-dimethyl-1-pyrroline N-oxide. Au-5 nm enhanced the HRP peroxidase activity toward ascorbic acid and the HRP compound I/II reactivity toward redox-active residues in the HRP protein moiety. Further, Au-5 nm also decreased the catalase- and oxidase-like activities of HRP. Au-10 nm showed similar, but weaker effects, while Au-15 nm, Au-30 nm and Au-60 nm had no effect. Results suggest that AuNPs can size-dependently enhance or inhibit HRP bioreactivity toward substrates with different redox potentials via a mechanism involving extension of the HRP substrate access channel and decline in the redox potentials of HRP catalytic intermediates.
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Affiliation(s)
- Haohao Wu
- College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
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30
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Paleček E, Tkáč J, Bartošík M, Bertók T, Ostatná V, Paleček J. Electrochemistry of nonconjugated proteins and glycoproteins. Toward sensors for biomedicine and glycomics. Chem Rev 2015; 115:2045-108. [PMID: 25659975 PMCID: PMC4360380 DOI: 10.1021/cr500279h] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Indexed: 02/07/2023]
Affiliation(s)
- Emil Paleček
- Institute
of Biophysics Academy of Science of the Czech Republic, v.v.i., Královopolská
135, 612 65 Brno, Czech Republic
| | - Jan Tkáč
- Institute
of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38 Bratislava, Slovakia
| | - Martin Bartošík
- Regional
Centre for Applied Molecular Oncology, Masaryk
Memorial Cancer Institute, Žlutý kopec 7, 656 53 Brno, Czech Republic
| | - Tomáš Bertók
- Institute
of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38 Bratislava, Slovakia
| | - Veronika Ostatná
- Institute
of Biophysics Academy of Science of the Czech Republic, v.v.i., Královopolská
135, 612 65 Brno, Czech Republic
| | - Jan Paleček
- Central
European Institute of Technology, Masaryk
University, Kamenice
5, 625 00 Brno, Czech Republic
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31
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Geng J, Davis I, Liu A. Probing Bis-FeIVMauG: Experimental Evidence for the Long-Range Charge-Resonance Model. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410247] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Thiruppathi D, Karuppasamy P, Ganesan M, Sivasubramanian VK, Rajendran T, Rajagopal S. Electron transfer reactions of methionine peptides with photochemically generated ruthenium(III)–polypyridyl complexes. J Photochem Photobiol A Chem 2014. [DOI: 10.1016/j.jphotochem.2014.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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33
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34
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Pilmé J, Luppi E, Bergès J, Houée-Lévin C, de la Lande A. Topological analyses of time-dependent electronic structures: application to electron-transfers in methionine enkephalin. J Mol Model 2014; 20:2368. [PMID: 25060148 DOI: 10.1007/s00894-014-2368-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 06/22/2014] [Indexed: 10/25/2022]
Abstract
We have studied electron transfers (ET) between electron donors and acceptors, taking as illustrative example the case of ET in methionine enkephalin. Recent pulse and gamma radiolysis experiments suggested that an ultrafast ET takes place from the C-terminal tyrosine residue to the N-terminal, oxidized, methionine residue. According to standard theoretical frameworks like the Marcus theory, ET can be decomposed into two successive steps: i) the achievement through thermal fluctuations, of a set of nuclear coordinates associated with degeneracy of the two electronic states, ii) the electron tunneling from the donor molecular orbital to the acceptor molecular orbital. Here, we focus on the analysis of the time-dependent electronic dynamics during the tunneling event. This is done by extending the approaches based on the topological analyses of stationary electronic density and of the electron localization function (ELF) to the time-dependent domain. Furthermore, we analyzed isosurfaces of the divergence of the current density, showing the paths that are followed by the tunneling electron from the donor to the acceptor. We show how these functions can be calculated with constrained density functional theory. Beyond this work, the topological tools used here can open up new opportunities for the electronic description in the time-dependent domain.
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Affiliation(s)
- Julien Pilmé
- Laboratoire de Chimie Théorique, UPMC Université Paris 06, UMR 7616, F-75005, Paris, France,
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35
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Ignasiak MT, Marciniak B, Houée-Levin C. A Long Story of Sensitized One-Electron Photo-oxidation of Methionine. Isr J Chem 2014. [DOI: 10.1002/ijch.201300109] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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36
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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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37
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Berthelot V, Steinmetz V, Alvarez LA, Houée-Levin C, Merola F, Rusconi F, Erard M. An analytical workflow for the molecular dissection of irreversibly modified fluorescent proteins. Anal Bioanal Chem 2013; 405:8789-98. [PMID: 24026516 DOI: 10.1007/s00216-013-7326-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 07/08/2013] [Accepted: 07/11/2013] [Indexed: 12/01/2022]
Abstract
Owing to their ability to be genetically expressed in live cells, fluorescent proteins have become indispensable markers in cellular and biochemical studies. These proteins can undergo a number of covalent chemical modifications that may affect their photophysical properties. Among other mechanisms, such covalent modifications may be induced by reactive oxygen species (ROS), as generated along a variety of biological pathways or through the action of ionizing radiations. In a previous report [1], we showed that the exposure of cyan fluorescent protein (ECFP) to amounts of (•)OH that mimic the conditions of intracellular oxidative bursts (associated with intense ROS production) leads to observable changes in its photophysical properties in the absence of any direct oxidation of the ECFP chromophore. In the present work, we analyzed the associated structural modifications of the protein in depth. Following the quantified production of (•)OH, we devised a complete analytical workflow based on chromatography and mass spectrometry that allowed us to fully characterize the oxidation events. While methionine, tyrosine, and phenylalanine were the only amino acids that were found to be oxidized, semi-quantitative assessment of their oxidation levels showed that the protein is preferentially oxidized at eight residue positions. To account for the preferred oxidation of a few, poorly accessible methionine residues, we propose a multi-step reaction pathway supported by data from pulsed radiolysis experiments. The described experimental workflow is widely generalizable to other fluorescent proteins, and opens the door to the identification of crucial covalent modifications that affect their photophysics.
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Affiliation(s)
- Vivien Berthelot
- Laboratoire de Chimie Physique, UMR CNRS 8000, Building 350, 91405, Orsay Cedex, France
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