Low-energy electron diffraction and induced damage in hydrated DNA.
J Chem Phys
; 128(19): 195102, 2008 May 21.
Article
en En
| MEDLINE
| ID: mdl-18500900
ABSTRACT
Elastic scattering of 5-30 eV electrons within the B-DNA 5'-CCGGCGCCGG-3' and A-DNA 5'-CGCGAATTCGCG-3' DNA sequences is calculated using the separable representation of a free-space electron propagator and a curved wave multiple scattering formalism. The disorder brought about by the surrounding water and helical base stacking leads to a featureless amplitude buildup of elastically scattered electrons on the sugar and phosphate groups for all energies between 5 and 30 eV. However, some constructive interference features arising from diffraction are revealed when examining the structural waters within the major groove. These appear at 5-10, 12-18, and 22-28 eV for the B-DNA target and at 7-11, 12-18, and 18-25 eV for the A-DNA target. Although the diffraction depends on the base-pair sequence, the energy dependent elastic scattering features are primarily associated with the structural water molecules localized within 8-10 A spheres surrounding the bases and/or the sugar-phosphate backbone. The electron density buildup occurs in energy regimes associated with dissociative electron attachment resonances, direct electronic excitation, and dissociative ionization. Since diffraction intensity can be localized on structural water, compound H2ODNA states may contribute to energy dependent low-energy electron induced single and double strand breaks.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Biofisica
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Daño del ADN
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ADN
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Química Física
Idioma:
En
Revista:
J Chem Phys
Año:
2008
Tipo del documento:
Article
País de afiliación:
Estados Unidos