Koizumi Kenichi, Hatakeyama Makoto, Boero Mauro, Nobusada Katsuyuki, Hori Hirokazu, Misonou Taku, Nakamura Shinichiro
Department of Theoretical and Computational Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan.
Phys Chem Chem Phys. 2017 Jun 21;19(24):15745-15753. doi: 10.1039/c7cp02699d.
We report an atomistic insight into the mechanism regulating the energy released by a porphyra-334 molecule, the ubiquitous photosensitive component of marine algae, in a liquid water environment upon an electron excitation. To quantify this rapidly occurring process, we resort to the Fourier analysis of the mass-weighted auto-correlation function, providing evidence for a remarkable dynamic change in the number of hydrogen bonds among water molecules and between the porphyra-334 and its surrounding hydrating water. Hydrogen bonds between the porphyra-334 and close by water molecules can act directly and rather easily to promote an efficient transfer of the excess kinetic energies of the porphyra-334 to the surrounding solvating water molecules via an activation of the collective modes identified as hydrogen-bond stretching modes in liquid water which eventually results in a disruption of the hydrogen bond network. Since porphyra-334 is present in seaweeds, aquatic cyanobacteria (blue-green algae) and red algae, our findings allow addressing the question how algae in oceans or lakes, upon sunlight absorption, can release large amounts of energy into surrounding water without destabilizing neither their own nor the HO molecular structure.
我们报告了对调节紫菜-334分子（海藻中普遍存在的光敏成分）在液态水环境中电子激发后释放能量的机制的原子层面见解。为了量化这个快速发生的过程，我们采用了质量加权自相关函数的傅里叶分析，这为水分子之间以及紫菜-334与其周围水化水之间氢键数量的显著动态变化提供了证据。紫菜-334与附近水分子之间的氢键可以直接且相当容易地通过激活被确定为液态水中氢键拉伸模式的集体模式，将紫菜-334的多余动能有效地转移到周围的溶剂化水分子，最终导致氢键网络的破坏。由于紫菜-334存在于海藻、水生蓝细菌（蓝藻）和红藻中，我们的研究结果有助于解决这样一个问题：海洋或湖泊中的藻类在吸收阳光后，如何在不破坏自身和水分子结构的情况下，将大量能量释放到周围水中。
