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Sosnovsky DV, Morozova OB, Yurkovskaya AV, Ivanov KL. Relation between CIDNP formed upon geminate and bulk recombination of radical pairs. J Chem Phys 2017; 147:024303. [DOI: 10.1063/1.4986243] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Denis V. Sosnovsky
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia and Novosibirsk State University, Novosibirsk 630090, Russia
| | - Olga B. Morozova
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia and Novosibirsk State University, Novosibirsk 630090, Russia
| | - Alexandra V. Yurkovskaya
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia and Novosibirsk State University, Novosibirsk 630090, Russia
| | - Konstantin L. Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk 630090, Russia and Novosibirsk State University, Novosibirsk 630090, Russia
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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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Morozova OB, Yurkovskaya AV. Aminium Cation Radical of Glycylglycine and its Deprotonation to Aminyl Radical in Aqueous Solution. J Phys Chem B 2008; 112:12859-62. [DOI: 10.1021/jp807149a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Olga B. Morozova
- International Tomography Center of SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia, and Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Alexandra V. Yurkovskaya
- International Tomography Center of SB RAS, Institutskaya 3a, 630090 Novosibirsk, Russia, and Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany
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4
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Hu Y, Bernstein ER. Vibrational and photoionization spectroscopy of biomolecules: Aliphatic amino acid structures. J Chem Phys 2008; 128:164311. [DOI: 10.1063/1.2902980] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Reece SY, Seyedsayamdost MR, Stubbe J, Nocera DG. Photoactive Peptides for Light-Initiated Tyrosyl Radical Generation and Transport into Ribonucleotide Reductase. J Am Chem Soc 2007; 129:8500-9. [PMID: 17567129 DOI: 10.1021/ja0704434] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanism of radical transport in the alpha2 (R1) subunit of class I E. coli ribonucleotide reductase (RNR) has been investigated by the phototriggered generation of a tyrosyl radical, *Y356, on a 20-mer peptide bound to alpha2. This peptide, Y-R2C19, is identical to the C-terminal peptide tail of the beta2 (R2) subunit and is a known competitive inhibitor of binding of the native beta2 protein to alpha2. *Y356 radical initiation is prompted by excitation (lambda >or= 300 nm) of a proximal anthraquinone, Anq, or benzophenone, BPA, chromophore on the peptide. Transient absorption spectroscopy has been employed to kinetically characterize the radical-producing step by time resolving the semiquinone anion (Anq*-), ketyl radical (*-BPA), and Y* photoproducts on (i) BPA-Y and Anq-Y dipeptides and (ii) BPA/Anq-Y-R2C19 peptides. Light-initiated, single-turnover assays have been carried out with the peptide/alpha2 complex in the presence of [14C]-labeled cytidine 5'-diphosphate substrate and ATP allosteric effector. We show that both the Anq- and BPA-containing peptides are competent in deoxycytidine diphosphate formation and turnover occurs via Y731 to Y730 to C439 pathway-dependent radical transport in alpha2. Experiments with the Y730F mutant exclude a direct superexchange mechanism between C439 and Y731 and are consistent with a PCET model for radical transport in which there is a unidirectional transport of the electron and proton transport among residues of alpha2.
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Affiliation(s)
- Steven Y Reece
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA
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Görner H. Electron transfer from aromatic amino acids to triplet quinones. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2007; 88:83-9. [PMID: 17604179 DOI: 10.1016/j.jphotobiol.2007.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 05/03/2007] [Accepted: 05/03/2007] [Indexed: 10/23/2022]
Abstract
The photoreduction of 1,4-benzoquinone, 1,4-naphthoquinone, 9,10-anthraquinone (AQ) and several methylated or halogenated derivatives in argon-saturated acetonitrile-water mixtures by indole, N-acetyltryptophan and N-acetyltyrosine was studied by time-resolved UV-vis spectroscopy using 20 ns UV laser pulses. The quinone triplet state is quenched by the aromatic amino acids and the rate constants are (1-5)x10(9)M(-1)s(-1). The semiquinone radical anion Q.(-) is the major observable transient after electron transfer from amino acids to the quinone triplet state. Termination of Q.(-) and amino acid derived radicals takes place in the mus-ms range. The effects of structure and other specific properties of quinones and amino acids are discussed. The radicals are subjects of intercept with oxygen, whereby hydrogen peroxide is eventually formed. The quantum yield of oxygen uptake Phi(-O2) as a measure of formation of hydrogen peroxide increases with increasing amino acid concentration, approaching Phi(-O2) for AQ in air-saturated solution.
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Affiliation(s)
- Helmut Görner
- Max-Planck-Institut für Bioanorganische Chemie, D-45413 Mülheim an der Ruhr, Germany.
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Abstract
Photoionization dynamics of beta-alanine is studied by the trajectory simulations using the ab initio potential energy surface. Vertical photoionization in the spirit of the Franck-Condon principle is assumed both for the adiabatic and thermostatic simulations. Both intramolecular proton transfer and fragmentation while only the proton transfer are found in the thermostatic and adiabatic simulations, respectively, for the conformer having the intramolecular hydrogen bond N...H-O. The theoretical predictions are in line with the experimental observations available in the literatures. It is reported for the first time that the thermostatic temperatures strongly affect the fragmentation processes induced by photoionization.
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Affiliation(s)
- Shan Xi Tian
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
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Gil A, Bertran J, Sodupe M. Effects of ionization on N-glycylglycine peptide: Influence of intramolecular hydrogen bonds. J Chem Phys 2006; 124:154306. [PMID: 16674225 DOI: 10.1063/1.2181970] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ionization effects on 28 conformations of N-glycylglycine are analyzed by means of the hybrid B3LYP and the hybrid meta-MPWB1K density functionals and by single-point calculations at the CCSD(T) level of theory. The most favorable process observed corresponds to the ionization of the only neutral conformation that presents a OH...NH2 intramolecular hydrogen bond, which leads to CO2 elimination after a spontaneous proton transfer from -COOH to NH2. The remaining neutral structures evolve to 20 different conformations of N-glycylglycine radical cation, which lie about 25-40 kcal/mol higher than the decarboxylated [NH3CH2CONHCH2]+*...[CO2] complex. Structural changes induced by ionization depend on the intramolecular hydrogen bonds of the initial conformation, since they determine the nature of the electron hole formed. In most cases, ionization takes place at the terminal -NH2 and -CO of the amide bond, which produces a strengthening of the peptide bond and the formation of new -NH2...OC(amide) and -NH2...OCOH hydrogen bonds. However, if -NH2 and -CO(amide) simultaneously act as proton acceptor in the neutral conformation, ionization is mainly localized at the carboxylic group, which produces a strengthening of the -COOH...OC(amide) bond. Both functionals lead to similar trends and compare well with CCSD(T) results except for a few cases for which B3LYP provides a too delocalized picture of the electron hole and consequently leads to artificial geometry reorganization.
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Affiliation(s)
- Adrià Gil
- Department de Química, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain
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White RC, Tarasov VF, Forbes MDE. Photooxidation of diglycine in confined media. Application of the microreactor model for spin-correlated radical pairs in reverse micelles and water-in-oil microemulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:2721-2727. [PMID: 15779940 DOI: 10.1021/la047382x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Time-resolved electron paramagnetic resonance spectra (X-band) of correlated radical pairs created in AOT reverse micelles and microemulsions are presented, simulated, and discussed using the microreactor model. The radicals are formed inside the water pool using photooxidation of diglycine by the excited triplet states of two different anthraquinone sulfonate salts. Water pool size and temperature effects on the spectra are reported, and the simulations allow for extraction of the diffusion coefficient in the interior, which monotonically increases with water pool size. The data directly correlate with the diffusional properties of correlated radical pairs in regular aqueous micelle solutions studied previously by similar methods. Competition between H-atom abstraction and electron transfer is observed with anthraquinone sulfonate, but electron transfer is the only reaction pathway observed when anthraquinone disulfonate triplet state is the sensitizing species.
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Affiliation(s)
- Ryan C White
- Venable and Kenan Laboratories, Department of Chemistry, CB #3290, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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Hill RR, Moore SA, Roberts DR. The Photochemistry of N-p-Toluenesulfonyl Peptides: The Peptide Bond as an Electron Donor. Photochem Photobiol 2005; 81:1439-46. [PMID: 16117565 DOI: 10.1562/2005-04-29-ra-507] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The scope of photobiological processes that involve absorbers within a protein matrix may be limited by the vulnerability of the peptide group to attack by highly reactive redox centers consequent upon electronic excitation. We have explored the nature of this vulnerability by undertaking comprehensive product analyses of aqueous photolysates of 12 N-p-toluenesulfonyl peptides with systematically selected structures. The results indicate that degradation includes a major pathway that is initiated by intramolecular electron transfer in which the peptide bond serves as electron donor, and the data support the likelihood of a relay process in dipeptide derivatives.
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Affiliation(s)
- Roger R Hill
- Chemistry Department, The Open University, Milton Keynes, UK.
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