5 Bromouracil

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Leticia Gonzalez - One of the best experts on this subject based on the ideXlab platform.

  • Insights into the deactivation of 5-Bromouracil after ultraviolet excitation.
    Philosophical transactions. Series A Mathematical physical and engineering sciences, 2017
    Co-Authors: Francesca Peccati, Sebastian Mai, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after ultraviolet irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and non-adiabatic dynamics simulations. It is found that, after irradiation to the bright ππ* state, three main relaxation pathways are, in principle, possible: relaxation back to the ground state, intersystem crossing (ISC) and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground-state relaxation should be the predominant deactivation pathway in the gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS (multi-reference configuration interaction including single excitations) was used in surface hopping simulations to compute the ultrafast ISC dynamics, which mostly involves the 1nOπ* and 3ππ* states.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

  • Cartesian coordinates of optimiized geometries from Insights into the deactivation of 5-Bromouracil after ultraviolet excitation
    2017
    Co-Authors: Francesca Peccati†, Sebastian Mai†, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after UV irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and non-adiabatic dynamics simulations. It is found that after irradiation to the bright ππ* state, three main relaxation pathways are, in principle, possible: relaxation back to the ground state, intersystem crossing (ISC) and C–Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground-state relaxation should be the predominant deactivation pathway in gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS was used in surface hopping simulations to compute the ultrafast ISC dynamics, which mostly involves the 1nOπ* and 3ππ* states.This article is part of the themed issue ‘Theoretical and computational studies of non-equilibrium and non-statistical dynamics in gas phase, condensed phase and interfaces’

  • insights into the deactivation of 5 Bromouracil after uv excitation
    arXiv: Chemical Physics, 2016
    Co-Authors: Francesca Peccati, Sebastian Mai, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after UV irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and nonadiabatic dynamics simulations. It is found that after irradiation to the bright 1pipi* state, three main relaxation pathways are in principle possible: relaxation back to the ground state, intersystem crossing, and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground state relaxation should be the predominant deactivation pathway in gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS was used in surface hopping simulations to compute the ultrafast intersystem crossing dynamics, which mostly involves the 1nOpi* and 3pipi* states.

Francesca Peccati - One of the best experts on this subject based on the ideXlab platform.

  • Insights into the deactivation of 5-Bromouracil after ultraviolet excitation.
    Philosophical transactions. Series A Mathematical physical and engineering sciences, 2017
    Co-Authors: Francesca Peccati, Sebastian Mai, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after ultraviolet irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and non-adiabatic dynamics simulations. It is found that, after irradiation to the bright ππ* state, three main relaxation pathways are, in principle, possible: relaxation back to the ground state, intersystem crossing (ISC) and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground-state relaxation should be the predominant deactivation pathway in the gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS (multi-reference configuration interaction including single excitations) was used in surface hopping simulations to compute the ultrafast ISC dynamics, which mostly involves the 1nOπ* and 3ππ* states.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

  • insights into the deactivation of 5 Bromouracil after uv excitation
    arXiv: Chemical Physics, 2016
    Co-Authors: Francesca Peccati, Sebastian Mai, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after UV irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and nonadiabatic dynamics simulations. It is found that after irradiation to the bright 1pipi* state, three main relaxation pathways are in principle possible: relaxation back to the ground state, intersystem crossing, and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground state relaxation should be the predominant deactivation pathway in gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS was used in surface hopping simulations to compute the ultrafast intersystem crossing dynamics, which mostly involves the 1nOpi* and 3pipi* states.

Jaroslav Kočišek - One of the best experts on this subject based on the ideXlab platform.

  • Energy Transfer in Microhydrated Uracil, 5-Fluorouracil and 5-Bromouracil
    The journal of physical chemistry. B, 2017
    Co-Authors: Jan Poštulka, Petr Slavíček, Juraj Fedor, Michal Fárník, Jaroslav Kočišek
    Abstract:

    Experiment and theory are combined to study the interaction of low energy electrons with microhydrated uracil and its halogenated analogues 5-fluorouracil and 5-Bromouracil. We report electron ionization (EI) and electron attachment (EA) mass spectra for the uracils with different degrees of hydration. Both EI and EA lead to evaporation of water molecules. The number of evaporated molecules serves as a measure of the energy transferred to the solvent. Upon EI, the amount of energy transferred to neighboring water molecules is similar for all three studied species. On the other hand, the energy transferred upon EA rises significantly from uracil to 5-fluorouracil and 5-Bromouracil. 5-Bromouracil is the only studied molecule that undergoes dissociative electron attachment after hydration at the studied energy of 1.2 eV. Theoretical modeling of the energetics for the electron attachment process allows for setting the energy transferred to the solvent on the absolute scale. We discuss the importance of this e...

Sebastian Mai - One of the best experts on this subject based on the ideXlab platform.

  • Insights into the deactivation of 5-Bromouracil after ultraviolet excitation.
    Philosophical transactions. Series A Mathematical physical and engineering sciences, 2017
    Co-Authors: Francesca Peccati, Sebastian Mai, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after ultraviolet irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and non-adiabatic dynamics simulations. It is found that, after irradiation to the bright ππ* state, three main relaxation pathways are, in principle, possible: relaxation back to the ground state, intersystem crossing (ISC) and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground-state relaxation should be the predominant deactivation pathway in the gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS (multi-reference configuration interaction including single excitations) was used in surface hopping simulations to compute the ultrafast ISC dynamics, which mostly involves the 1nOπ* and 3ππ* states.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.

  • insights into the deactivation of 5 Bromouracil after uv excitation
    arXiv: Chemical Physics, 2016
    Co-Authors: Francesca Peccati, Sebastian Mai, Leticia Gonzalez
    Abstract:

    5-Bromouracil is a nucleobase analogue that can replace thymine in DNA strands and acts as a strong radiosensitizer, with potential applications in molecular biology and cancer therapy. Here, the deactivation of 5-Bromouracil after UV irradiation is investigated in the singlet and triplet manifold by accurate quantum chemistry calculations and nonadiabatic dynamics simulations. It is found that after irradiation to the bright 1pipi* state, three main relaxation pathways are in principle possible: relaxation back to the ground state, intersystem crossing, and C-Br photodissociation. Based on accurate MS-CASPT2 optimizations, we propose that ground state relaxation should be the predominant deactivation pathway in gas phase. We then employ different electronic structure methods to assess their suitability to carry out excited-state dynamics simulations. MRCIS was used in surface hopping simulations to compute the ultrafast intersystem crossing dynamics, which mostly involves the 1nOpi* and 3pipi* states.

Dai Ayusawa - One of the best experts on this subject based on the ideXlab platform.

  • 5-Bromouracil disrupts nucleosome positioning by inducing A-form-like DNA conformation in yeast cells.
    Biochemical and biophysical research communications, 2008
    Co-Authors: Kensuke Miki, Michihiko Fujii, Mitsuhiro Shimizu, Mohammad Nazir Hossain, Dai Ayusawa
    Abstract:

    Abstract 5-Bromodeoxyuridine (BrdU) modulates expression of particular genes associated with cellular differentiation and senescence. Our previous studies have suggested an involvement of chromatin structure in this phenomenon. Here, we examined the effect of 5-Bromouracil on nucleosome positioning in vivo using TALS plasmid in yeast cells. This plasmid can stably and precisely be assembled nucleosomes aided by the α2 repressor complex bound to its α2 operator. Insertion of AT-rich sequences into a site near the operator destabilized nucleosome positioning dependent on their length and sequences. Addition of BrdU almost completely disrupted nucleosome positioning through specific AT-tracts. The effective AT-rich sequences migrated faster on polyacrylamide gel electrophoresis, and their mobility was further accelerated by substitution of thymine with 5-Bromouracil. Since this property is indicative of a rigid conformation of DNA, our results suggest that 5-Bromouracil disrupts nucleosome positioning by inducing A-form-like DNA.

  • Binding of 5-Bromouracil-containing S/MAR DNA to the Nuclear Matrix
    DNA research : an international journal for rapid publication of reports on genes and genomes, 2002
    Co-Authors: Hideki Ogino, Michihiko Fujii, Wataru Satou, Toshikazu Suzuki, Eriko Michishita, Dai Ayusawa
    Abstract:

    Substitution of thymine with 5-Bromouracil in DNA is known to change interaction between DNA and proteins, thereby inducing various biological phenomena. We hypothesize that A/T-rich scaffold/nuclear matrix attachment region (S/MAR) sequences are involved in the effects of 5-bromodeoxyuridine. We examined an interaction between DNA containing an intronic S/MAR sequence of the immunoglobulin heavy chain gene and nuclear halos prepared from HeLa cells. Upon substitution with 5-Bromouracil, the S/MAR DNA bound more tightly to the nuclear halos. The multi-functional nuclear matrix protein YY1 was also found to bind more strongly to 5-Bromouracil-substituted DNA containing its recognition motif. These results are consistent with the above hypothesis.