General Chemistry-Algemene Chemie, Vrije Universiteit Brussel, Brussels, Belgium.
J Phys Chem B. 2013 Aug 22;117(33):9669-76. doi: 10.1021/jp406320g. Epub 2013 Aug 7.
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-O (P-O(3') and P-O(5')) and C-C (C(3')-C(4') and C(4')-C(5')) bonds for which the acquired kinetic energy becomes high enough so that the neighboring C(3')-O(3') or C(5')-O(5') phosphodiester bond may break almost immediately. Such dynamic behavior should happen on a very short time scale, within 15-30 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-O phosphodiester bonds can break before electron transfer from the backbone to the base.
这里分析了低能电子俘获诱导 DNA 损伤，其中离解通道可能涉及多个键，包括复杂的键重排和显著的核运动。量子力学/分子力学（QM/MM）计算揭示了垂直电子附加后电子密度的重排如何调节 DNA 中原子核的位置和动力学。核运动涉及 P-O（P-O(3') 和 P-O(5')）和 C-C（C(3')-C(4') 和 C(4')-C(5'））键的伸长，获得的动能变得足够高，以至于相邻的 C(3')-O(3'）或 C(5')-O(5'）磷酸二酯键可能几乎立即断裂。这种动态行为应该在非常短的时间内发生，在 15-30 fs 内，与预测的多余电子在碱基周围局部化的时间尺度相同。这一结果表明，在电子从骨架转移到碱基之前，C-O 磷酸二酯键可能会断裂。
