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Multiple valence electron detachment following Auger decay of inner-shell vacancies in gas-phase DNA
Chemical Science ( IF 7.6 ) Pub Date : 2021-09-10 , DOI: 10.1039/d1sc02885e Wen Li 1 , Oksana Kavatsyuk 2 , Wessel Douma 1 , Xin Wang 1 , Ronnie Hoekstra 1 , Dennis Mayer 3 , Matthew S Robinson 3, 4 , Markus Gühr 3 , Mathieu Lalande 5 , Marwa Abdelmouleh 5 , Michal Ryszka 5 , Jean Christophe Poully 5 , Thomas Schlathölter 1
Chemical Science ( IF 7.6 ) Pub Date : 2021-09-10 , DOI: 10.1039/d1sc02885e Wen Li 1 , Oksana Kavatsyuk 2 , Wessel Douma 1 , Xin Wang 1 , Ronnie Hoekstra 1 , Dennis Mayer 3 , Matthew S Robinson 3, 4 , Markus Gühr 3 , Mathieu Lalande 5 , Marwa Abdelmouleh 5 , Michal Ryszka 5 , Jean Christophe Poully 5 , Thomas Schlathölter 1
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We have studied soft X-ray photoabsorption in the doubly deprotonated gas-phase oligonucleotide [dTGGGGT–2H]2−. The dominating decay mechanism of the X-ray induced inner shell vacancy was found to be Auger decay with detachment of at least three electrons, leading to charge reversal of the anionic precursor and the formation of positively charged photofragment ions. The same process is observed in heavy ion (12 MeV C4+) collisions with [dTGGGGT–2H]2− where inner shell vacancies are generated as well, but with smaller probability. Auger decay of a single K-vacancy in DNA, followed by detachment of three or more low energy electrons instead of a single high energy electron has profound implications for DNA damage and damage modelling. The production of three low kinetic energy electrons with short mean free path instead of one high kinetic energy electron with long mean free path implies that electron-induced DNA damage will be much more localized around the initial K-shell vacancy. The fragmentation channels, triggered by triple electron detachment Auger decay are predominantly related to protonated guanine base loss and even loss of protonated guanine dimers is tentatively observed. The fragmentation is not a consequence of the initial K-shell vacancy but purely due to multiple detachment of valence electrons, as a very similar positive ion fragmentation pattern is observed in femtosecond laser-induced dissociation experiments.
中文翻译：
气相 DNA 内壳空位俄歇衰变后的多价电子脱离
我们研究了双去质子化气相寡核苷酸 [dTGGGGT-2H] 2− 中的软 X 射线光吸收。发现 X 射线诱导的内壳空位的主要衰变机制是俄歇衰变，至少三个电子脱离，导致阴离子前体的电荷反转并形成带正电荷的光碎片离子。在重离子 (12 MeV C 4+ ) 与 [dTGGGGT–2H] 2−碰撞中观察到相同的过程其中内壳空位也会产生，但概率较小。DNA 中单个 K 空位的俄歇衰变，随后分离三个或更多低能电子而不是单个高能电子，这对 DNA 损伤和损伤建模具有深远的影响。产生三个平均自由程短的低动能电子而不是一个平均自由程长的高动能电子意味着电子诱导的 DNA 损伤将更多地集中在初始 K 壳空位周围。由三电子脱离俄歇衰变触发的碎裂通道主要与质子化鸟嘌呤碱基丢失有关，甚至暂时观察到质子化鸟嘌呤二聚体的丢失。
更新日期：2021-09-16
中文翻译：
气相 DNA 内壳空位俄歇衰变后的多价电子脱离
我们研究了双去质子化气相寡核苷酸 [dTGGGGT-2H] 2− 中的软 X 射线光吸收。发现 X 射线诱导的内壳空位的主要衰变机制是俄歇衰变，至少三个电子脱离，导致阴离子前体的电荷反转并形成带正电荷的光碎片离子。在重离子 (12 MeV C 4+ ) 与 [dTGGGGT–2H] 2−碰撞中观察到相同的过程其中内壳空位也会产生，但概率较小。DNA 中单个 K 空位的俄歇衰变，随后分离三个或更多低能电子而不是单个高能电子，这对 DNA 损伤和损伤建模具有深远的影响。产生三个平均自由程短的低动能电子而不是一个平均自由程长的高动能电子意味着电子诱导的 DNA 损伤将更多地集中在初始 K 壳空位周围。由三电子脱离俄歇衰变触发的碎裂通道主要与质子化鸟嘌呤碱基丢失有关，甚至暂时观察到质子化鸟嘌呤二聚体的丢失。
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