||Ultrafast Proton Transfer between DNA-Sugar Molecule and Hydrated Water induced by K-Ionization of Oxygen
藤井, 健太郎 ,
Marie-Francois, Politis ,
Marie-Anne, Herve du Penhoat横谷, 明徳
In order to investigate the role of hydrated water molecules for DNA strand breakage induced by ionizing radiations, we observed the mass pattern of the desorbing ions ejected after an ionization of oxygen K-shell electrons of water deposited 2-deoxy-D-ribose (dR) film. The experiment were performed at synchrotron radiation facility (SPring-8) to obtain the monochromatic soft X-rays for inducing the ionizations. The experimental result shows that the yield of fragment ion species such as CHO+, C3H3+ or C2HO+, desorbing after a degradation of the furanose ring in a sugar molecule, remarkably decreased by hydration. We also performed DFT-MD calculation to simulate the dynamics after K-shell ionization. The simulation result shows that a proton is transferred from dR to hydrated water molecule within the ultrafast time scale (<10 fs) after the ionization. This charge re-distribution would contribute to decrease the desorption of fragment species. The hydrated water might protect the sugar site in DNA from the degradation by ionizing radiation.
第１回国際シンポジウム 「量子生命科学 -Quantum Life Science-」