Search results for "thymine"
showing 10 items of 73 documents
Photostability and Photoreactivity in Biomolecules: Quantum Chemistry of Nucleic Acid Base Monomers and Dimers
2008
The great potentials of high-level ab initio methods, in particular, the CASPT2//CASSCF protocol, are fully illustrated through: (i) the study of ultrafast energy relaxation in DNA/RNA base monomers, (ii) the intrinsic population mechanism of the lowest triplet state, and (iii) how bioexcimers can be considered as precursors of charge transfer and photoinduced reactivity. In order to describe these processes properly, the presence of conical intersections (CIs) and the topology of the involved pathways have to be determined correctly. Thus, in theoretical calculations the dynamic electronic correlation has to be considered. The accessibility of the CIs (or the seam of CIs) becomes crucial t…
Induction capacity and influence of dThdMP on thymidine kinase activity of type 1 and 2 strains of herpes simplex virus
1978
The thymidine kinase inducing ability of 104 strains of herpes simplex virus was studied comparatively. A pronounced relationship was established between induction of the enzyme and the serotype of the strains. As a rule, the strains of serotype 2 are weaker inducer of dThd- and dCyd-kinase activity than serotype 1 strains. A certain parallelism exists between induction of both enzymes, however the activity of the thymidine kinase increases after infection with herpes simplex virus 4--5 times more than that of the dCyd-kinase. Adaptation of the strains to cell cultures only slightly modifies the inducing ability of the herpes simplex virus strains. The thymidine kinase activity induced by H…
CCDC 949550: Experimental Crystal Structure Determination
2013
Related Article: Pilar Amo-Ochoa, Oscar Castillo, Carlos J. Gómez-García, Khaled Hassanein, Sandeep Verma, Jitendra Kumar, and Félix Zamora|2013|Inorg.Chem.|52|11428|doi:10.1021/ic401758w
CCDC 949551: Experimental Crystal Structure Determination
2013
Related Article: Pilar Amo-Ochoa, Oscar Castillo, Carlos J. Gómez-García, Khaled Hassanein, Sandeep Verma, Jitendra Kumar, and Félix Zamora|2013|Inorg.Chem.|52|11428|doi:10.1021/ic401758w
CCDC 177552: Experimental Crystal Structure Determination
2003
Related Article: R.K.O.Sigel, E.Freisinger, M.Abbate, B.Lippert|2002|Inorg.Chim.Acta|339|355|doi:10.1016/S0020-1693(02)00962-3
CCDC 1934515: Experimental Crystal Structure Determination
2019
Related Article: Verónica G. Vegas, Noelia Maldonado, Oscar Castillo, Carlos J. Gómez-García, Pilar Amo-Ochoa|2019|J.Inorg.Biochem.|200|110805|doi:10.1016/j.jinorgbio.2019.110805
CCDC 1934513: Experimental Crystal Structure Determination
2019
Related Article: Verónica G. Vegas, Noelia Maldonado, Oscar Castillo, Carlos J. Gómez-García, Pilar Amo-Ochoa|2019|J.Inorg.Biochem.|200|110805|doi:10.1016/j.jinorgbio.2019.110805
CCDC 177551: Experimental Crystal Structure Determination
2003
Related Article: R.K.O.Sigel, E.Freisinger, M.Abbate, B.Lippert|2002|Inorg.Chim.Acta|339|355|doi:10.1016/S0020-1693(02)00962-3
Structure and properties of hydroxyl radical modified nucleic acid components II. 8-Oxo-adenine and 8-oxo-2′-deoxy-adenosine
1997
Abstract The tautomerism of the 8-oxo-adenine (8-oxo-A) and 8-oxo-2′-deoxy-adenosine (8-oxo-dA) was analysed on the basis of semiempirical, SCF ab initio and DFT density functional quantum chemistry calculations. The results of full gradient geometry optimisation of all possible 8-oxo-A and 8-oxo-dA structures lead to the conclusion that the most stable form is 8-keto-6-amino-tautomer. The second stable tautomer corresponds to 8-hydroxy-isomer. Such an order was unchanged after solvating process. In all studied solvents: water, methanol, acetone, cyclohexane the keto-tautomer proceeds the enol one. The preferred N-glycoside torsion angle corresponds to syn rotamer of 8-oxo-dA in all studied…
Hypoxia-Selective Dissociation Mechanism of a Nitroimidazole Nucleoside in a DNA Environment
2019
Photodynamic therapy is a promising approach to treat a variety of superficial tumors and other diseases. One of its major limitations arises from its dependence on molecular oxygen, which decreases the efficiency of the therapy in hypoxia conditions commonly developed by solid tumors. The present contribution reveals the molecular mechanism of a modified thymine bearing a nitroimidazole substituent, a photosensitizer able to produce highly harmful interstrand cross-links in the DNA double strand after irradiation selectively in absence of oxygen. The mechanism is resolved at a fully atomistic and electronic level relying on quantum mechanics (CASPT2, coupled-cluster, DFT, and TD-DFT method…