Zhu Zhe, Higashi Masahiro, Saito Shinji
The Graduate University for Advanced Studies (SOKENDAI), 38 Nishigo-Naka, Myodaiji, Okazaki, Aichi 444-8585, Japan.
Department of Complex Systems Science, Graduate School of Informatics, Nagoya University, Furo-cho, Chikusa-ward, Nagoya, Aichi 464-8601, Japan.
J Chem Theory Comput. 2025 Jan 14;21(1):413-427. doi: 10.1021/acs.jctc.4c01214. Epub 2024 Dec 20.
The light-harvesting complex II (LHCII) in green plants exhibits highly efficient excitation energy transfer (EET). A comprehensive understanding of the EET mechanism in LHCII requires quantum chemical, molecular dynamics (MD), and statistical mechanics calculations that can adequately describe pigment molecules in heterogeneous environments. Herein, we develop MD simulation parameters that accurately reproduce the quantum mechanical/molecular mechanical energies of both the ground and excited states of all chlorophyll (Chl) molecules in membrane embedded LHCII. The present simulations reveal that Chl molecules reside in more inhomogeneous environments than Chl molecules. We also find a narrow gap between the exciton energy levels of Chl and Chl . In addition, we investigate the nature of the exciton states of Chl molecules, such as delocalization, and analyze the optical spectra of LHCII, which align with experimental results. Thus, the MD simulation parameters developed in this study successfully reproduce the excitonic and optical properties of the Chl molecules in LHCII, validating their effectiveness.
绿色植物中的捕光复合物II（LHCII）表现出高效的激发能量转移（EET）。要全面理解LHCII中的EET机制，需要进行量子化学、分子动力学（MD）和统计力学计算，这些计算能够充分描述异质环境中的色素分子。在此，我们开发了MD模拟参数，该参数能准确再现膜嵌入LHCII中所有叶绿素（Chl）分子基态和激发态的量子力学/分子力学能量。目前的模拟结果表明，Chl分子所处的环境比Chl分子的环境更不均匀。我们还发现Chl和Chl的激子能级之间存在狭窄的差距。此外，我们研究了Chl分子激子态的性质，如离域，并分析了LHCII的光谱，其与实验结果一致。因此，本研究中开发的MD模拟参数成功再现了LHCII中Chl分子的激子和光学性质，验证了其有效性。
