Institute of Physics, Vilnius, Lithuania.
Phys Chem Chem Phys. 2009 Sep 21;11(35):7576-84. doi: 10.1039/b901848d.
Excitation energy transfer and trapping by the artificially postulated traps in photosystem II (PSII) were modeled in terms of a coarse-grained model. The model is based on the assumption that the excitation energy transfer within a pigment-protein complex is much faster than the intercomplex excitation energy transfer. As a result, the excitation energy transfer and trapping rates by the reaction center (RC) were rescaled by the relevant entropic factors and an additional trapping rate for a specific pigment-protein complex responsible for the non-photochemical quenching (NPQ) had to be included into the theoretical framework. For the analysis, dimeric models of PSII were considered. The efficiency of the excitation quenching by the NPQ traps, depending on their positioning and on the trapping rate, was analyzed. It was concluded that the highest efficiency of the NPQ quencher could be achieved when they are localized in the major light-harvesting complexes, LHCII, and the excitation relaxation in this state is fast, of the order of picoseconds and even faster. The origin of the state responsible for NPQ is discussed.
采用粗粒化模型对光系统 II（PSII）中人为假定的陷阱的激发能量转移和俘获进行了建模。该模型基于这样一种假设，即在色素-蛋白复合物内的激发能量转移比复合物间的激发能量转移快得多。因此，反应中心（RC）的激发能量转移和俘获速率通过相关的熵因子进行了调整，并且必须将负责非光化学猝灭（NPQ）的特定色素-蛋白复合物的额外俘获速率纳入理论框架。在分析中，考虑了 PSII 的二聚体模型。分析了 NPQ 陷阱的定位和俘获速率对激发猝灭效率的影响。得出的结论是，当 NPQ 猝灭剂定位于主要的光捕获复合物 LHCII 中时，它们可以达到最高的猝灭效率，并且在这种状态下的激发弛豫速度很快，为皮秒级甚至更快。讨论了导致 NPQ 的状态的起源。
