2023 Fiscal Year Final Research Report

Quantum mechanism and regulation of radiation damage to DNA

Research Project

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Project/Area Number	20H04338
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 63020:Radiation influence-related
Research Institution	National Institutes for Quantum Science and Technology
Principal Investigator	YOKOYA Akinari 国立研究開発法人量子科学技術研究開発機構, 量子生命科学研究所, 専門業務員 (10354987)
Co-Investigator(Kenkyū-buntansha)	黒川悠索認定NPO法人量子化学研究協会, 研究所, 研究員 (30590731) 鵜飼正敏東京農工大学, 工学(系)研究科(研究院), 名誉教授 (80192508)
Project Period (FY)	2020-04-01 – 2024-03-31
Keywords	DNA損傷 / DNA電子物性 / ハロゲン化DNA / シンクロトロン放射 / X線光電子分光 / X線吸収微細構造 / バンドギャップ / 金属化
Outline of Final Research Achievements	To understand the mechanism underlying the radiation damage to DNA, which are thought to be a major cause of radiation effects such as mutation, experiments of X-ray spectroscopy and theoretical approaches were conducted in terms of a quantum mechanical point of view. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy were applied to elucidate the electronic properties of DNA related molecules, particularly energy gaps between the valence and conduction levels. The experimental evidence was compared with the energy levels obtained by quantum chemical calculation. The findings strongly suggest that the bromination or iodination of DNA significantly reduce the energy gap, indicating that the DNA obtains a metal-like property by the halogenations. This electric nature may open a novel quantum control technique to regulate DNA damage induction and resulting radiation effects on cells.
Free Research Field	放射線生物物理学
Academic Significance and Societal Importance of the Research Achievements	X線分光実験と量子化学的な理論研究を両輪として、生体に対する放射線の照射効果をDNA分子の電子物性の観点から解明したことは本研究が世界でも初めてである。特に臭素など重いハロゲン原子の取り込みによる生体の放射線増感の主要因は、DNA分子の金属化に起因すると推測され放射線生物学に新たに量子的視点を提供した。また金属化レベルはハロゲン原子の重さに依存して大きくなることから、がんの放射線治療における放射線増感剤の探索にDNA分子の電子物性が新たな手がかりとなると考えられる。