1
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Ma C, Xiong Q, Lin J, Zeng X, Wang M, Kwok WM. Is 1-methylcytosine a faithful model compound for ultrafast deactivation dynamics of cytosine nucleosides in solution? Phys Chem Chem Phys 2024; 26:2963-2972. [PMID: 38214513 DOI: 10.1039/d3cp05509d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
1-Methylcytosine (1mCyt) is the base for nucleoside N1-methylpseudodeoxycytidine of Hachimoji nucleic acids and a frequently used model compound for theoretical studies on excited states of cytosine nucleosides. However, there is little experimental characterization of spectra and photo-dynamic properties of 1mCyt. Herein, we report a comprehensive investigation into excited state dynamics and effects of solvents on fluorescence dynamics of 1mCyt in both water and acetonitrile. The study employed femtosecond broadband time-resolved fluorescence, transient absorption, and steady-state spectroscopy, along with density functional theory and time-dependent density functional theory calculations. The results obtained provide the first experimental evidence for identifying a dark-natured ∼5.7 ps lifetime nπ* state in the ultrafast non-radiative deactivation with 1mCyt in aqueous solution. This study also demonstrates a significant effect of the solvent on 1mCyt's fluorescence emission, which highlights the crucial role of solute-solvent hydrogen bonding in altering structures and reshaping the radiative as well as nonradiative dynamics of the 1mCyt's ππ* state in the aprotic solvent compared to the protic solvent. The solvent effect exhibited by 1mCyt is distinctive from that known for deoxycytidine, indicating the need for caution in using 1mCyt for modelling the ultrafast dynamics of Cyt nucleosides in solvents with varying properties. Overall, our study unveils a deactivation mechanism that confers a high degree of photo-stability for 1mCyt in solution, shedding light on the molecular basis for solvent-induced effects on the excited state dynamics of nucleobases and derivatives.
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Affiliation(s)
- Chensheng Ma
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, 518071, P. R. China.
| | - Qingwu Xiong
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, 518071, P. R. China.
- College of Physics and optoelectronic Engineering, Shenzhen University, Shenzhen, Guangdong, P. R. China
| | - Jingdong Lin
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, 518071, P. R. China.
| | - Xiaoyan Zeng
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, 518071, P. R. China.
| | - Mingliang Wang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, Guangdong, 518071, P. R. China.
| | - Wai-Ming Kwok
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, P. R. China.
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2
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Bezabih MS, Kaliakin DS, Blanco-González A, Barneschi L, Tarnovsky AN, Olivucci M. Comparative Study of Uracil Excited-State Photophysics in Water and Acetonitrile via RMS-CASPT2-Driven Quantum-Classical Trajectories. J Phys Chem B 2023; 127:10871-10879. [PMID: 38055701 DOI: 10.1021/acs.jpcb.3c06433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
We present a nonadiabatic molecular dynamics study of the ultrafast processes occurring in uracil upon UV light absorption, leading to electronic excitation and subsequent nonradiative decay. Previous studies have indicated that the mechanistic details of this process are drastically different depending on whether the process takes place in the gas phase, acetonitrile, or water. However, such results have been produced using quantum chemical methods that did not incorporate both static and dynamic electron correlation. In order to assess the previously proposed mechanisms, we simulate the photodynamics of uracil in the three environments mentioned above using quantum-classical trajectories and, for solvated uracil, hybrid quantum mechanics/molecular mechanics (QM/MM) models driven by the rotated multistate complete active space second-order perturbation (RMS-CASPT2) method. To do so, we exploit the gradient recently made available in OpenMolcas and compare the results to those obtained using the complete active space self-consistent field (CASSCF) method only accounting for static electron correlation. We show that RMS-CASPT2 produces, in general, a mechanistic picture different from the one obtained at the CASSCF level but confirms the hypothesis advanced on the basis of previous ROKS and TDDFT studies thus highlighting the importance of incorporating dynamic electron correlation in the investigation of ultrafast electronic deactivation processes.
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Affiliation(s)
- Meseret Simachew Bezabih
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Danil S Kaliakin
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | | | - Leonardo Barneschi
- Dipartimento di Biotechnologie, Chimica e Farmacia, Università di Siena, I-53100 Siena, Italy
| | - Alexander N Tarnovsky
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
| | - Massimo Olivucci
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, United States
- Dipartimento di Biotechnologie, Chimica e Farmacia, Università di Siena, I-53100 Siena, Italy
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3
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Ortín-Fernández J, González-Vázquez J, Martínez-Fernández L, Corral I. Molecular Identification of the Transient Species Mediating the Deactivation Dynamics of Solvated Guanosine and Deazaguanosine. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030989. [PMID: 35164254 PMCID: PMC8839017 DOI: 10.3390/molecules27030989] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/16/2022]
Abstract
Small structural alterations of the purine/pyrimidine core have been related to important photophysical changes, such as the loss of photostability. Similarly to canonical nucleobases, solute-solvent interactions can lead to a change in the excited state lifetimes and/or to the interplay of different states in the photophysics of these modified nucleobases. To shed light on both effects, we here report a complete picture of the absorption spectra and excited state deactivation of deoxyguanosine and its closely related derivative, deoxydeazaguanosine, in water and methanol through the mapping of the excited state potential energy surfaces and molecular dynamics simulations at the TD-DFT level of theory. We show that the N by CH exchange in the imidazole ring of deoxyguanosine translates into a small red-shift of the bright states and slightly faster dynamics. In contrast, changing solvent from water to methanol implies the opposite, i.e., that the deactivation of both systems to the ground state is significantly hindered.
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Affiliation(s)
- Javier Ortín-Fernández
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (J.O.-F.); (J.G.-V.)
| | - Jesús González-Vázquez
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (J.O.-F.); (J.G.-V.)
- Institute for Advanced Research in Chemistry (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Lara Martínez-Fernández
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (J.O.-F.); (J.G.-V.)
- Institute for Advanced Research in Chemistry (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Correspondence: (L.M.-F.); (I.C.)
| | - Inés Corral
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid, Spain; (J.O.-F.); (J.G.-V.)
- Institute for Advanced Research in Chemistry (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Correspondence: (L.M.-F.); (I.C.)
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4
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Martínez-Fernández L, Pepino AJ, Segarra-Martí J, Banyasz A, Garavelli M, Improta R. Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models. J Chem Theory Comput 2016; 12:4430-9. [DOI: 10.1021/acs.jctc.6b00518] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- L. Martínez-Fernández
- Istituto di Biostrutture
e Bioimmagini, CNR, Via Mezzocannone
16, I-80134 Napoli, Italy
| | - A. J. Pepino
- Dipartimento
di Chimica “G. Ciamician”, Università di Bologna, Bologna, Italy
| | - J. Segarra-Martí
- Dipartimento
di Chimica “G. Ciamician”, Università di Bologna, Bologna, Italy
- École
Normale Supérieure de Lyon, CNRS, UMR 5182, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07, France
| | - A. Banyasz
- LIDYL,
CEA, CNRS, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - M. Garavelli
- Dipartimento
di Chimica “G. Ciamician”, Università di Bologna, Bologna, Italy
- École
Normale Supérieure de Lyon, CNRS, UMR 5182, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07, France
| | - R. Improta
- Istituto di Biostrutture
e Bioimmagini, CNR, Via Mezzocannone
16, I-80134 Napoli, Italy
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5
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Improta R, Santoro F, Blancafort L. Quantum Mechanical Studies on the Photophysics and the Photochemistry of Nucleic Acids and Nucleobases. Chem Rev 2016; 116:3540-93. [PMID: 26928320 DOI: 10.1021/acs.chemrev.5b00444] [Citation(s) in RCA: 338] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The photophysics and photochemistry of DNA is of great importance due to the potential damage of the genetic code by UV light. Quantum mechanical studies have played a key role in interpretating the results of modern time-resolved pump-probe spectroscopy, and in elucidating the main photoactivated reactive paths. This review provides a concise, complete picture of the computational studies carried out, approximately, in the past decade. We start with an overview of the photophysics of the nucleobases in the gas phase and in solution. We discuss the proposed mechanisms for ultrafast decay to the ground state, that involve conical intersections, consider the role of triplet states, and analyze how the solvent modulates the photophysics. Then we move to larger systems, from dinucleotides to single- and double-stranded oligonucleotides. We focus on the possible role of charge transfer and delocalized or excitonic states in the photophysics of these systems and discuss the main photochemical paths. We finish with an outlook on the current challenges in the field and future directions of research.
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Affiliation(s)
- Roberto Improta
- Istituto di Biostrutture Biommagini (IBB-CNR), CNR-Consiglio Nazionale delle Ricerche , Via Mezzocannone 16, I-80134, Napoli, Italy
| | - Fabrizio Santoro
- Area della Ricerca di Pisa, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), CNR-Consiglio Nazionale delle Ricerche , Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, Campus de Montilivi , 17071 Girona, Spain
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6
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Hršak D, Marefat Khah A, Christiansen O, Hättig C. Polarizable Embedded RI-CC2 Method for Two-Photon Absorption Calculations. J Chem Theory Comput 2015; 11:3669-78. [PMID: 26574450 DOI: 10.1021/acs.jctc.5b00496] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We present a novel polarizable embedded resolution-of-identity coupled cluster singles and approximate doubles (PERI-CC2) method for calculation of two-photon absorption (TPA) spectra of large molecular systems. The method was benchmarked for three types of systems: a water-solvated molecule of formamide, a uracil molecule in aqueous solution, and a set of mutants of the channelrhodopsin (ChR) protein. The first test case shows that the PERI-CC2 method is in excellent agreement with the PE-CC2 method and in good agreement with the PE-CCSD method. The uracil test case indicates that the effects of hydrogen bonding on the TPA of a chromophore with the nearest environment is well-described with the PERI-CC2 method. Finally, the ChR calculation shows that the PERI-CC2 method is well-suited and efficient for calculations on proteins with medium-sized chromophores.
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Affiliation(s)
- Dalibor Hršak
- Center for Oxygen Microscopy and Imaging, Aarhus University , Langelandsgade 140, 8000 Aarhus, Denmark
| | - Alireza Marefat Khah
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum , Universitätsstraße 150, 44801 Bochum, Germany
| | - Ove Christiansen
- Center for Oxygen Microscopy and Imaging, Aarhus University , Langelandsgade 140, 8000 Aarhus, Denmark
| | - Christof Hättig
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum , Universitätsstraße 150, 44801 Bochum, Germany
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7
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D’Abramo M, Aschi M, Amadei A. Theoretical modeling of UV-Vis absorption and emission spectra in liquid state systems including vibrational and conformational effects: Explicit treatment of the vibronic transitions. J Chem Phys 2014; 140:164104. [DOI: 10.1063/1.4871626] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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8
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Inclusion of cybotactic effect in the theoretical modeling of absorption spectra of liquid-state systems with perturbed matrix method and molecular dynamics simulations: the UV–Vis absorption spectrum of para-nitroaniline as a case study. Theor Chem Acc 2014. [DOI: 10.1007/s00214-014-1478-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Excited States Behavior of Nucleobases in Solution: Insights from Computational Studies. Top Curr Chem (Cham) 2014; 355:329-57. [DOI: 10.1007/128_2013_524] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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10
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ZHAO YUAN, CAO ZEXING. ABSORPTION SPECTRA OF NUCLEIC ACID BASES IN WATER ENVIRONMENT: INSIGHTS INTO FROM COMBINED QM/MM AND CLUSTER-CONTINUUM MODEL CALCULATIONS. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2013. [DOI: 10.1142/s0219633613410137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Electronic spectra of uracil, thymine, adenine, guanine, and cytosine in the gas phase and aqueous solution have been studied by extensive time-dependent density functional calculations. Calculations show that the Quantum mechanics/molecular mechanics (QM/MM) geometry optimization based on the molecular dynamics (MD) equilibrated configuration can locate an optimal solvated cluster for the base solvation, and the combined QM/MM and cluster-continuum computational protocol is capable of handling the solvent effect on the excited states of nucleic acid bases and providing realistic absorption spectra in water environment with relatively low computational costs. Generally, the vertical excitation energies in aqueous solution by PCM/TD-X3LYP calculations show excellent agreement with the experimental observations and the maximum deviation is less than 0.2 eV. The present results reveal that the hydrogen bond network around the excited-state base and its dipole moment change may remarkably modify the absorption spectra of nucleic acid bases in aqueous solution.
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Affiliation(s)
- YUAN ZHAO
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 360015, P. R. China
| | - ZEXING CAO
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 360015, P. R. China
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11
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Cattenacci G, Aschi M, Graziano G, Amadei A. A theoretical study on the spectral and electrochemical properties of Ferrocene in different solvents. Inorganica Chim Acta 2013. [DOI: 10.1016/j.ica.2013.07.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Aschi M, Amadei A, Pellegrino A, Perin N, Po’ R. Thermal and environmental effects on Oligothiophene low-energy singlet electronic excitations in dilute solution: a theoretical and experimental study. Theor Chem Acc 2012. [DOI: 10.1007/s00214-012-1177-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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13
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Ren HS, Li YK, Zhu Q, Zhu J, Li XY. Spectral shifts of the n → π* and π → π* transitions of uracil based on a modified form of solvent reorganization energy. Phys Chem Chem Phys 2012; 14:13284-91. [DOI: 10.1039/c2cp41047h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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14
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Zazza C, Olsen JM, Kongsted J. Solvatochromic shifts vs nanosolvation patterns: Uracil in water as a test case. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.07.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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15
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Picconi D, Barone V, Lami A, Santoro F, Improta R. The Interplay between ππ*/nπ* Excited States in Gas-Phase Thymine: A Quantum Dynamical Study. Chemphyschem 2011; 12:1957-68. [DOI: 10.1002/cphc.201001080] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 03/01/2011] [Indexed: 11/10/2022]
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16
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Bányász Á, Karpati S, Mercier Y, Reguero M, Gustavsson T, Markovitsi D, Improta R. The Peculiar Spectral Properties of Amino-Substituted Uracils: A Combined Theoretical and Experimental Study. J Phys Chem B 2010; 114:12708-19. [DOI: 10.1021/jp105267q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Ákos Bányász
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Szilvia Karpati
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Yannick Mercier
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Mar Reguero
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Thomas Gustavsson
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Dimitra Markovitsi
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
| | - Roberto Improta
- Laboratoire Francis Perrin, CEA/DSM/IRAMIS/SPAM - CNRS URA 2453, 91191 Gif-sur-Yvette, France, Departament de Química Física i Inorgànica, Universitat Rovira i Virgili, Marcel·lí Domingo, s/n-Campus Sescelades, 43007 Tarragona, Spain, and Istituto Biostrutture e Bioimmagini-CNR, Via Mezzocannone 16, I-80134 Napoli, Italy
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17
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Zazza C, Coletta A, Sanna N, Chillemi G, Mancini G, Desideri A. Solvent Effects on the Valence UV−Vis Absorption Spectra of Topotecan Anticancer Drug in Aqueous Solution at Room Temperature: A Nanoseconds Time-Scale TD-DFT/MD Computational Study. J Phys Chem B 2010; 114:6770-8. [PMID: 20438088 DOI: 10.1021/jp1015824] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Costantino Zazza
- CASPUR, Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca, Via dei Tizii, 6/b, 00185 Roma, Italy, and Dipartimento di Biologia, Università di Roma “Tor Vergata”, via della Ricerca Scientifica, 00133 Roma, Italy
| | - Andrea Coletta
- CASPUR, Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca, Via dei Tizii, 6/b, 00185 Roma, Italy, and Dipartimento di Biologia, Università di Roma “Tor Vergata”, via della Ricerca Scientifica, 00133 Roma, Italy
| | - Nico Sanna
- CASPUR, Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca, Via dei Tizii, 6/b, 00185 Roma, Italy, and Dipartimento di Biologia, Università di Roma “Tor Vergata”, via della Ricerca Scientifica, 00133 Roma, Italy
| | - Giovanni Chillemi
- CASPUR, Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca, Via dei Tizii, 6/b, 00185 Roma, Italy, and Dipartimento di Biologia, Università di Roma “Tor Vergata”, via della Ricerca Scientifica, 00133 Roma, Italy
| | - Giordano Mancini
- CASPUR, Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca, Via dei Tizii, 6/b, 00185 Roma, Italy, and Dipartimento di Biologia, Università di Roma “Tor Vergata”, via della Ricerca Scientifica, 00133 Roma, Italy
| | - Alessandro Desideri
- CASPUR, Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca, Via dei Tizii, 6/b, 00185 Roma, Italy, and Dipartimento di Biologia, Università di Roma “Tor Vergata”, via della Ricerca Scientifica, 00133 Roma, Italy
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18
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Aschi M, Fontana A, Meo EMD, Zazza C, Amadei A. Characterization of Electronic Properties in Complex Molecular Systems: Modeling of a Micropolarity Probe. J Phys Chem B 2010; 114:1915-24. [DOI: 10.1021/jp909465f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Massimiliano Aschi
- Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università di L’Aquila, via Vetoio (Coppito 1), 67010 L’Aquila, Italy; Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, Via dei Vestini 31, 66013 Chieti, Italy; Supercomputing Center for University and Research, CASPUR, via dei Tizii 6/b, 00185 Rome, Italy; and Dipartimento di Scienze e Tecnologie Chimiche, Università di Tor Vergata, via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Antonella Fontana
- Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università di L’Aquila, via Vetoio (Coppito 1), 67010 L’Aquila, Italy; Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, Via dei Vestini 31, 66013 Chieti, Italy; Supercomputing Center for University and Research, CASPUR, via dei Tizii 6/b, 00185 Rome, Italy; and Dipartimento di Scienze e Tecnologie Chimiche, Università di Tor Vergata, via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Erika Maria Di Meo
- Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università di L’Aquila, via Vetoio (Coppito 1), 67010 L’Aquila, Italy; Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, Via dei Vestini 31, 66013 Chieti, Italy; Supercomputing Center for University and Research, CASPUR, via dei Tizii 6/b, 00185 Rome, Italy; and Dipartimento di Scienze e Tecnologie Chimiche, Università di Tor Vergata, via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Costantino Zazza
- Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università di L’Aquila, via Vetoio (Coppito 1), 67010 L’Aquila, Italy; Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, Via dei Vestini 31, 66013 Chieti, Italy; Supercomputing Center for University and Research, CASPUR, via dei Tizii 6/b, 00185 Rome, Italy; and Dipartimento di Scienze e Tecnologie Chimiche, Università di Tor Vergata, via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Andrea Amadei
- Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università di L’Aquila, via Vetoio (Coppito 1), 67010 L’Aquila, Italy; Dipartimento di Scienze del Farmaco, Università “G. d’Annunzio”, Via dei Vestini 31, 66013 Chieti, Italy; Supercomputing Center for University and Research, CASPUR, via dei Tizii 6/b, 00185 Rome, Italy; and Dipartimento di Scienze e Tecnologie Chimiche, Università di Tor Vergata, via della Ricerca Scientifica 1, I-00133 Rome, Italy
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Etinski M, Marian CM. Ab initio investigation of the methylation and hydration effects on the electronic spectra of uracil and thymine. Phys Chem Chem Phys 2010; 12:4915-23. [DOI: 10.1039/b925677f] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Zazza C, Palma A, Amadei A, Sanna N, Tatoli S, Aschi M. On the catalytic role of structural fluctuations in enzyme reactions: computational evidence on the formation of compound 0 in horseradish peroxidase. Faraday Discuss 2010. [DOI: 10.1039/b906614d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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QM/MM Approaches to the Electronic Spectra of Hydrogen-Bonding Systems with Connection to Many-Body Decomposition Schemes. ADVANCES IN QUANTUM CHEMISTRY 2010. [DOI: 10.1016/s0065-3276(10)59004-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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22
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Zazza C, Sanna N. Photoabsorption spectra of a natural polyphenol compound for therapeutic applications: the protocatechuic acid in dilute water solution at room temperature. Phys Chem Chem Phys 2010; 12:3859-63. [DOI: 10.1039/b925237a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Olsen JM, Aidas K, Mikkelsen KV, Kongsted J. Solvatochromic Shifts in Uracil: A Combined MD-QM/MM Study. J Chem Theory Comput 2009; 6:249-56. [DOI: 10.1021/ct900502s] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Jógvan Magnus Olsen
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. Ørsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Kęstutis Aidas
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. Ørsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Kurt V. Mikkelsen
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. Ørsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Jacob Kongsted
- Department of Physics and Chemistry, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark, and Department of Chemistry, H. C. Ørsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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Improta R, Barone V, Lami A, Santoro F. Quantum Dynamics of the Ultrafast ππ*/nπ* Population Transfer in Uracil and 5-Fluoro-Uracil in Water and Acetonitrile. J Phys Chem B 2009; 113:14491-503. [DOI: 10.1021/jp906524p] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Roberto Improta
- Dipartimento di Chimica and INSTM-Village, Universitá Federico II, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy, Scuola Normale Superiore di Pisa, P.zza dei Cavalieri 7, I-56126 Pisa, Italy, and Istituto per i Processi Chimico-Fisici - CNR, Area della Ricerca del CNR Via Moruzzi,1 I-56124 Pisa, Italy
| | - Vincenzo Barone
- Dipartimento di Chimica and INSTM-Village, Universitá Federico II, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy, Scuola Normale Superiore di Pisa, P.zza dei Cavalieri 7, I-56126 Pisa, Italy, and Istituto per i Processi Chimico-Fisici - CNR, Area della Ricerca del CNR Via Moruzzi,1 I-56124 Pisa, Italy
| | - Alessandro Lami
- Dipartimento di Chimica and INSTM-Village, Universitá Federico II, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy, Scuola Normale Superiore di Pisa, P.zza dei Cavalieri 7, I-56126 Pisa, Italy, and Istituto per i Processi Chimico-Fisici - CNR, Area della Ricerca del CNR Via Moruzzi,1 I-56124 Pisa, Italy
| | - Fabrizio Santoro
- Dipartimento di Chimica and INSTM-Village, Universitá Federico II, Complesso Monte S. Angelo, via Cintia, I-80126 Napoli, Italy, Scuola Normale Superiore di Pisa, P.zza dei Cavalieri 7, I-56126 Pisa, Italy, and Istituto per i Processi Chimico-Fisici - CNR, Area della Ricerca del CNR Via Moruzzi,1 I-56124 Pisa, Italy
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Kistler KA, Matsika S. Solvatochromic Shifts of Uracil and Cytosine Using a Combined Multireference Configuration Interaction/Molecular Dynamics Approach and the Fragment Molecular Orbital Method. J Phys Chem A 2009; 113:12396-403. [DOI: 10.1021/jp901601u] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Kurt A. Kistler
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Spiridoula Matsika
- Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
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Amadei A, D’Alessandro M, D’Abramo M, Aschi M. Theoretical characterization of electronic states in interacting chemical systems. J Chem Phys 2009; 130:084109. [DOI: 10.1063/1.3080887] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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Zazza C, Mancini G, Sanna N, Aschi M. Thermodynamic features and environmental effects in a two-states molecular device under strict electrochemical control. Theor Chem Acc 2009. [DOI: 10.1007/s00214-009-0523-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Quantum Mechanical Studies of the Photophysics of DNA and RNA Bases. CHALLENGES AND ADVANCES IN COMPUTATIONAL CHEMISTRY AND PHYSICS 2009. [DOI: 10.1007/978-1-4020-9956-4_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Epifanovsky E, Kowalski K, Fan PD, Valiev M, Matsika S, Krylov AI. On the Electronically Excited States of Uracil. J Phys Chem A 2008; 112:9983-92. [DOI: 10.1021/jp803758q] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Evgeny Epifanovsky
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, Pacific Northwest National Laboratory, Richland, Washington 99352, and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Karol Kowalski
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, Pacific Northwest National Laboratory, Richland, Washington 99352, and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Peng-Dong Fan
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, Pacific Northwest National Laboratory, Richland, Washington 99352, and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Marat Valiev
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, Pacific Northwest National Laboratory, Richland, Washington 99352, and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Spiridoula Matsika
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, Pacific Northwest National Laboratory, Richland, Washington 99352, and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
| | - Anna I. Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, Pacific Northwest National Laboratory, Richland, Washington 99352, and Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122
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Zazza C, Amadei A, Palma A, Sanna N, Tatoli S, Aschi M. Theoretical Modeling of Enzyme Reactions: The Thermodynamics of Formation of Compound 0 in Horseradish Peroxidase. J Phys Chem B 2008; 112:3184-92. [DOI: 10.1021/jp0774692] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Costantino Zazza
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), Via dei Tizii 6b, 00185 Roma, Italy, Dipartimento di Chimica, Ingegneria Chimica e Materiali Università di L'Aquila, via Vetoio 67100, L'Aquila, Italy, Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133, Roma, Italy, Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Via Salaria km 29.3, Sez. Montelibretti, Monterotondo S. (RM
| | - Andrea Amadei
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), Via dei Tizii 6b, 00185 Roma, Italy, Dipartimento di Chimica, Ingegneria Chimica e Materiali Università di L'Aquila, via Vetoio 67100, L'Aquila, Italy, Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133, Roma, Italy, Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Via Salaria km 29.3, Sez. Montelibretti, Monterotondo S. (RM
| | - Amedeo Palma
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), Via dei Tizii 6b, 00185 Roma, Italy, Dipartimento di Chimica, Ingegneria Chimica e Materiali Università di L'Aquila, via Vetoio 67100, L'Aquila, Italy, Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133, Roma, Italy, Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Via Salaria km 29.3, Sez. Montelibretti, Monterotondo S. (RM
| | - Nico Sanna
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), Via dei Tizii 6b, 00185 Roma, Italy, Dipartimento di Chimica, Ingegneria Chimica e Materiali Università di L'Aquila, via Vetoio 67100, L'Aquila, Italy, Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133, Roma, Italy, Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Via Salaria km 29.3, Sez. Montelibretti, Monterotondo S. (RM
| | - Simone Tatoli
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), Via dei Tizii 6b, 00185 Roma, Italy, Dipartimento di Chimica, Ingegneria Chimica e Materiali Università di L'Aquila, via Vetoio 67100, L'Aquila, Italy, Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133, Roma, Italy, Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Via Salaria km 29.3, Sez. Montelibretti, Monterotondo S. (RM
| | - Massimiliano Aschi
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), Via dei Tizii 6b, 00185 Roma, Italy, Dipartimento di Chimica, Ingegneria Chimica e Materiali Università di L'Aquila, via Vetoio 67100, L'Aquila, Italy, Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1 I-00133, Roma, Italy, Istituto per lo Studio dei Materiali Nanostrutturati, CNR-ISMN, Via Salaria km 29.3, Sez. Montelibretti, Monterotondo S. (RM
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Zazza C, Sanna N, Aschi M. Theoretical Study of α-84 Phycocyanobilin Chromophore from the Thermophilic Cyanobacterium Synechococcus elongatus. J Phys Chem B 2007; 111:5596-601. [PMID: 17461572 DOI: 10.1021/jp070994g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Time-dependent density functional theory (TD-DFT) calculations were performed to obtain vertical excitation energies from the ground state to different low-lying singlet excited states of the protonated alpha-84 phycocyanobilin chromophore (alpha-84 PCBH(+)). It clearly emerges that three gradient-corrected approximation functionals (B3LYP, PBE0, and PBEPBE) show a similar description, confirming the proposed valence assignment of the strongest UV-vis absorption band at 618 nm. Moreover, our results show that there are not appreciable differences, in terms of excitation wavelength of the main peak, between the alpha-84 PCBH(+) chromophore and a model system in which the two propionic chains have not been taken into account. Finally, with the precise aim of investigating the effects of alpha-84 PCBH(+) conformational fluctuations on its electronic properties, vertical excitation energies obtained for the potential energy local minimum structure were also refined using a recently proposed TD-DFT/principal component analysis/Car-Parrinello molecular dynamics computational approach. Interestingly, and in line with previous results on another photosensitive complex, this study essentially suggests that interaction with the surrounding environment (protein matrix plus solvent molecules) coupled with the large amplitude fluctuation of the whole C-Phycocyanin (C-PC) pigment protein can affect the electronic properties of the alpha-84 PCB chromophore and therefore its biological activity.
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Affiliation(s)
- Costantino Zazza
- Consorzio Interuniversitario per le Applicazioni di Supercalcolo per Università e Ricerca (CASPUR), via dei Tizii 6b, 00185 Rome, Italy.
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Ludwig V, Coutinho K, Canuto S. A Monte Carlo-quantum mechanics study of the lowest n–π* and π–π* states of uracil in water. Phys Chem Chem Phys 2007; 9:4907-12. [PMID: 17912421 DOI: 10.1039/b704335j] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The solvatochromic shifts of the n-pi(*) and pi-pi(*) states of uracil in water are analyzed using a combined and sequential Monte Carlo/quantum mechanics (MC/QM) approach. The role of the solute polarization and electronic delocalization into the solvent region are investigated. Electronic polarization of the solute is obtained using the HF/6-31G(d), the polarizable continuum model (PCM) and an iterative procedure using MP2/aug-cc-pVDZ in the MC/QM. The in-water dipole moment of uracil is obtained, respectively, as 5.12 D, 6.12 D and 7.01 +/- 0.05 D. This latter result, corresponding to an increase of 60% with respect to the gas phase value, is used in the classical potential of the MC simulation to obtain statistically uncorrelated configurations for subsequent QM calculations of the ultraviolet-visible absorption spectrum of uracil in water. QM calculations are performed at the time-dependent density-functional theory (TD-DFT) combined with the B3LYP and B3PW91 functionals, multiconfigurational (CASSCF) and the semi-empirical all-valence electron INDO/CIS methods. Using 60 solute-solvent configurations with the explicit inclusion of 200 water molecules the solvatochromic shift is obtained as a blue shift of 0.50 eV for the n-pi(*) state and a red shift of 0.19 eV for the pi-pi(*) state, in good agreement with experimentally-inferred values. These results are compared with TD-DFT results in conjunction with PCM approaches and the importance of solute polarization and wave function delocalization over the solvent region is discussed. Our results suggest that the elusive n-pi(*) state of uracil in water lies around 255 nm hidden by the intense and broad pi-pi(*) transition with a maximum at 260 nm, inverting the relative locations of these states compared to the gas phase. This is further supported by considering the in-water dipole moment changes upon excitation, as obtained from CASSCF calculations.
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Affiliation(s)
- Valdemir Ludwig
- Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, 05315-970, SP Brazil
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Merchán M, González-Luque R, Climent T, Serrano-Andrés L, Rodríguez E, Reguero M, Peláez D. Unified Model for the Ultrafast Decay of Pyrimidine Nucleobases. J Phys Chem B 2006; 110:26471-6. [PMID: 17181307 DOI: 10.1021/jp066874a] [Citation(s) in RCA: 207] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Ultrafast decay processes detected after absorption of UV radiation in gas-phase pyrimidine nucleobases uracil, thymine, and cytosine are ascribed to the barrierless character of the pathway along the low-lying 1(pipi*) hypersurface connecting the Franck-Condon region with an out-of-plane distorted ethene-like conical intersection with the ground state. Longer lifetime decays and low quantum yield emission are on the other hand related to the presence of a 1(pipi*) state planar minimum on the S1 surface and the barriers to access other conical intersections. A unified model for the three systems is established on the basis of accurate multiconfigurational CASPT2 calculations, whereas the effect of the different levels of theory on the results is carefully analyzed.
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Affiliation(s)
- Manuela Merchán
- Instituto de Ciencia Molecular, Universitat de València, Apartado 22085, ES-46071 Valencia, Spain
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