Electron-Attachment-Induced DNA Damage: Instantaneous Strand Breaks

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• 作者：Emilie Cau毛t ; Stuart Bogatko ; Jacques Li茅vin ; Frank De Proft ; Paul Geerlings
• 刊名：The Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：August 22, 2013
• 年：2013
• 卷：117
• 期：33
• 页码：9669-9676
• 全文大小：517K
• 年卷期：v.117,no.33(August 22, 2013)
• ISSN：1520-5207

文摘

Low energy electron-attachment-induced damage in DNA, where dissociation channels may involve multiple bonds including complex bond rearrangements and significant nuclear motions, is analyzed here. Quantum mechanics/molecular mechanics (QM/MM) calculations reveal how rearrangements of electron density after vertical electron attachment modulate the position and dynamics of the atomic nuclei in DNA. The nuclear motions involve the elongation of the P鈥揙 (P鈥?img src="/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-33/jp406320g/production/images/jp-2013-06320g_m001.gif" alt=""/> and P鈥?img src="/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-33/jp406320g/production/images/jp-2013-06320g_m002.gif" alt=""/>) and C鈥揅 (鈥?img src="/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-33/jp406320g/production/images/jp-2013-06320g_m004.gif" alt=""/> and 鈥?img src="/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-33/jp406320g/production/images/jp-2013-06320g_m006.gif" alt=""/>) bonds for which the acquired kinetic energy becomes high enough so that the neighboring 鈥?img src="/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-33/jp406320g/production/images/jp-2013-06320g_m008.gif" alt=""/> or 鈥?img src="/appl/literatum/publisher/achs/journals/content/jpcbfk/2013/jpcbfk.2013.117.issue-33/jp406320g/production/images/jp-2013-06320g_m010.gif" alt=""/> phosphodiester bond may break almost immediately. Such dynamic behavior should happen on a very short time scale, within 15鈥?0 fs, which is of the same order of magnitude as the time scale predicted for the excess electron to localize around the nucleobases. This result indicates that the C鈥揙 phosphodiester bonds can break before electron transfer from the backbone to the base.