Debnath Tushar, Mohd Yusof Muhammad Shafiq Bin, Low Pei Jiang, Loh Zhi-Heng
Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
Centre for Optical Fibre Technology, The Photonics Institute, Nanyang Technological University, Singapore, 639798, Singapore.
Nat Commun. 2019 Jul 3;10(1):2944. doi: 10.1038/s41467-019-10989-1.
The elementary processes that accompany the interaction of ionizing radiation with biologically relevant molecules are of fundamental importance. However, the ultrafast structural rearrangement dynamics induced by the ionization of biomolecules in aqueous solution remain hitherto unknown. Here, we employ femtosecond optical pump-probe spectroscopy to elucidate the vibrational wave packet dynamics that follow the photodetachment of phenoxide, a structural mimic of tyrosine, in aqueous solution. Photodetachment of phenoxide leads to wave packet dynamics of the phenoxyl radical along 12 different vibrational modes. Eight of the modes are totally symmetric and support structural rearrangement upon electron ejection. Comparison to a previous photodetachment study of phenoxide in the gas phase reveals the important role played by the solvent environment in driving ultrafast structural reorganization induced by ionizing radiation. This work provides insight into the ultrafast molecular dynamics that follow the interaction of ionizing radiation with molecules in aqueous solution.
伴随电离辐射与生物相关分子相互作用的基本过程至关重要。然而，迄今为止，水溶液中生物分子电离所引发的超快结构重排动力学仍不为人知。在此，我们采用飞秒光泵浦-探测光谱来阐明在水溶液中，酚盐（酪氨酸的结构模拟物）光解离后随之而来的振动波包动力学。酚盐的光解离导致苯氧基自由基沿12种不同振动模式的波包动力学。其中8种模式是完全对称的，并在电子射出时支持结构重排。与之前对气相中酚盐的光解离研究相比，揭示了溶剂环境在驱动电离辐射诱导的超快结构重组中所起的重要作用。这项工作为深入了解电离辐射与水溶液中分子相互作用后超快分子动力学提供了思路。
