Influence of Functional Groups on the Site‐Selective Dissociation of Adenine upon Low‐Energy Electron Attachment

Denifl, Stephan; Sulzer, Philipp; Huber, Dieter; Zappa, Fábio; Probst, Michael; Märk, T.D.; Scheier, P.; Injan, Natcha; Limtrakul, Jumras; Abouaf, R.; Dunet, H.

doi:10.1002/anie.200700032

Cited by 62 publications

(57 citation statements)

References 27 publications

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“…Denifl et al 29 showed that selective H cleavage from the N9 site of adenine can also be achieved in DEA, notably via resonances observed experimentally below around 1.07 eV. However, the present results cannot be understood purely on the basis of a direct analogy with DEA.…”

Section: Resultsmentioning

confidence: 53%

“…It is also interesting to consider the present results in the context of previously calculated electrostatic potential maps and isodensity maps of the lowest virtual σ * molecular orbitals at the B3LYP/augcc-pVTZ level for purine, adenine, and 6-dimethyladenine. 29 These show that for purine, the regions accessible for H loss are around the N9-H and C8-H sites, whereas in adenine and 6-dimethyladenine, an extra region around the NH 2 and N(CH 3 ) 2 groups is also available. Furthermore, these results show that there is no wave-function density in the C6-H region for purine.…”

Section: Resultsmentioning

confidence: 96%

“…However, the present results cannot be understood purely on the basis of a direct analogy with DEA. In DEA to adenine, the calculated minimum electron energy required to cleave a hydrogen atom from N9-H, (NH 2 )C6, C8-H, and C2-H and hence produce a dehydrogenated parent anion varies between 0.94 and 3.63 eV, 29 respectively. This is distinctly lower than the available energies in the centre-of-mass frame in the collisions probed in Fig.…”

Section: Resultsmentioning

confidence: 99%

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Communication: Site-selective bond excision of adenine upon electron transfer

Cunha

Mendes

Silva

et al. 2018

The Journal of Chemical Physics

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This work demonstrates that selective excision of hydrogen atoms at a particular site of the DNA base adenine can be achieved in collisions with electronegative atoms by controlling the impact energy. The result is based on analysing the time-of-flight mass spectra yields of potassium collisions with a series of labeled adenine derivatives. The production of dehydrogenated parent anions is consistent with neutral H loss either from selective breaking of C-H or N-H bonds.

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Section: Resultsmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

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Communication: Site-selective bond excision of adenine upon electron transfer

Cunha

Mendes

Silva

et al. 2018

The Journal of Chemical Physics

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“…These observations have stimulated significant interest in electron-molecule collisions with small biomolecules and the constituents of larger one, with particular emphasis on characterizing the resonance states of these systems. There are many studies of electron collisions with DNA building blocks [3][4][5][6][7][8][9] such as amino acids [10][11][12][13][14][15], nucleobase [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33], sugar and phosphate moieties [34][35][36][37][38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Low-energy electron collisions with the alanine molecule

2014

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Abstract.A theoretical study on elastic electron collisions with two conformers of amino acid alanine (CH3CH(NH2)COOH) is reported. Differential and integral cross sections are computed for collision energies in the 1-10 eV range. The UK molecular R-matrix codes are used to compute scattering amplitudes within the static exchange plus polarization (SEP) approximation. Both alanine conformers have large permanent dipole moment so to calculate cross sections the Born closure procedure is included to take into account long-range interactions. Comparisons of calculated differential cross sections with available data for glycine are made and display certain similarities. Two shape resonances are detected for each conformer: a narrow one located at 2.7 eV and 3.5 eV which is probably associated with the unoccupied π * orbital of the carboxyl group, and a broader resonance at 8.6 eV and 9.8 eV.

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“…A captura eletrônica dissociativa dá origem a cinco fragmentos, detectados Quanto ao canal de eliminação do hidrogênio, a similaridade entre as curvas da 2-cloroadenina e adenina [144][145][146] sugerem mecanismos de dissociação semelhantes nas duas moléculas. O mecanismo envolvendo o acoplamento do estado ligado por di-polo e a ressonância σ * NH [43,143,146] explica o sinal mais intenso da uracila [43] e da adenina [146], e tal mecanismo também deve operar para a 2-cloroadenina. Como já discutido, o elétron incidenteé capturado numa ressonância de Feshbach vibracional do estado ligado por dipolo, que então acopla com a ressonância dissociativa σ * NH .…”

Section: -Cloroadeninaunclassified

Dinâmica de íons temporários de biomoléculas halogenadas

Kossoski¹

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We present results on the anion spectrum and on the vibrational dynamics induced by electron capture, for a series of halogenated molecules. The anion states were characterized by means of elastic scattering calculations, in the fixed nuclei approximation, performed with the Schwinger multichannel method with pseudopotentials. Quantum dynamics calculations of the nuclear wavepacket were performed by the propagation on potential energy surfaces described in the local approximation. The target molecules comprise chloromethane, chloroethene, uracil, 5-fluorouracil, 5-chlorouracil, 5-bromouracil, 5-iodouracil, 6-chlorouracil, 2-thiouracil, adenine, 2-chloroadenine and 8-chloroadenine. For chloromethane we computed vibrational excitation cross sections for the C−Cl stretching, and showed this mode is promptly activated by the presence of the extra charge. For chloroethene, we demonstrated that the direct mechanism of dissociation is very inefficient, and also revealed the interesting topology of its complex potential energy surfaces. The derivatives of uracil presented rich anionic spectra, as each one has three π * delocalized states, a σ * state located at the bond between the substituted atom and the ring, and a dipole bound state. Overall, the obtained energetics are in very good agreement with experimental data. Analysis of the anionic spectra and the potential energy surfaces indicate mechanisms in which the anion is formed in a long-lived π * resonance and changes its character to the dissociative σ * state. For 5-chlorouracil in particular, this coupling is mediated by an out-of-plane movement of the chlorine atom. As the anion states progressively stabilize as the halogen atomic number increases, the couplings become more favorable, and account for the increasing dissociation cross sections. Our results explain many of the observed features of dissociative electron attachment to halouracils, providing a theoretical basis for its radiosensitizing ability. In chloroadenines, we found a σ * resonance and four π * resonances. We support they could also act as potential radiosensitizers.

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Influence of Functional Groups on the Site‐Selective Dissociation of Adenine upon Low‐Energy Electron Attachment

Cited by 62 publications

References 27 publications

Communication: Site-selective bond excision of adenine upon electron transfer

Communication: Site-selective bond excision of adenine upon electron transfer

Low-energy electron collisions with the alanine molecule

Dinâmica de íons temporários de biomoléculas halogenadas

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