Hyperthermal (1-100 eV) nitrogen ion scattering damage to D-ribose and 2-deoxy-D-ribose films
Abstract
Highly charged heavy ion traversal of a biological medium can produce energetic secondary fragment ions. These fragment ions can in turn cause collisional and reactive scattering damage to DNA. Here we report hyperthermal (1-100eV) scattering of one such fragment ion (N+) from biologically relevant sugar molecules D-ribose and 2-deoxy-D-ribose condensed on polycrystalline Pt substrate. The results indicate that N+ ion scattering at kinetic energies down to 10eV induces effective decomposition of both sugar molecules and leads to the desorption of abundant cation and anion fragments. Use of isotope-labeled molecules (5-C13 D-ribose and 1-D D-ribose) partly reveals some site specificity of the fragment origin. Several scattering reactions are also observed. Both ionic and neutral nitrogen atoms abstract carbon from the molecules to form CN - anion at energies down to ∼5eV. N+ ions also abstract hydrogen from hydroxyl groups of the molecules to form NH - and NH2- anions. A fraction of O /O- fragments abstract hydrogen to form OH -. The formation of H3O+ ions also involves hydrogen abstraction as well as intramolecular proton transfer. These findings suggest a variety of severe damaging pathways to DNA molecules which occur on the picosecond time scale following heavy ion irradiation of a cell, and prior to the late diffusion-limited homogeneous chemical processes.
- Publication:
-
Journal of Chemical Physics
- Pub Date:
- October 2007
- DOI:
- 10.1063/1.2772259
- Bibcode:
- 2007JChPh.127n4715D
- Keywords:
-
- 87.50.Gi;
- 87.15.Nn;
- 87.15.Mi;
- 87.16.Sr;
- 87.14.Gg;
- 82.39.Jn;
- Ionizing radiations;
- Properties of solutions;
- aggregation and crystallization of macromolecules;
- Spectra photodissociation and photoionization;
- luminescence;
- Chromosomes histones;
- DNA RNA;
- Charge transfer in biological systems