Reduced Minimum Model for the Photosynthetic Induction Processes in Photosystem I
Reduced Minimum Model for the Photosynthetic Induction Processes in Photosystem I
复制标题
光系统 I 中光合诱导过程的简化最小模型
DOI：
10.1016/j.jphotobiol.2016.04.009
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
K. Ebina
中科院分区：
文献类型：
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作者：
T. Matsuoka;S. Tanaka;K. Ebina
光系统I（PS I）是光合作用中最重要的蛋白质复合物之一，广泛存在于植物、藻类和蓝藻中。PS I及其周围环境响应的各种机制已被实验和理论阐明。在光合诱导期，PS I发生电子拥挤，实现PS I过还原态。这意味着PS I的氧化还原态的自由度变大，因此基于在状态空间中描述PS I的模型的现象的理解变得困难。为了直观地理解这些现象，我们利用分层粗粒化（HCG）方法将复杂的具有多时间尺度性质的电子和激发能转移过程的PS I模型简化为一个简单的具有单时间尺度性质的PS I模型.粗粒度模型用7个变量状态来描述PS I的状态，而原始模型用3 × 27（= 384）个状态来描述PS I。在此基础上，模拟了光合诱导期的I820（820 nm透射信号）曲线，并与实验结果进行了对比分析。关于该信号曲线，揭示了在10-3s时初始增加到肩部，从该点增加到2 × 10-2s时的峰值，以及在该峰值之后的衰减反映了P700+，Pc+和P700 FA-FB-（PS I状态，其中观察到P700，FA-和FB-）的积累。分别此外，还证实了P700+ A0 A-和P700+ A1 A-态的电荷复合过程对于光合诱导期额外吸收能量的耗散的重要作用。
Photosystem I (PS I) is one of the most important protein complexes for photosynthesis, which is present in plants, algae and cyanobacteria. A variety of mechanisms for environmental response in and around PS I have been elucidated experimentally and theoretically. During the photosynthetic induction time, the congestion of electron occurs in PS I and then the over-reduced PS I states are realized. This means that the degree of freedom of the redox states of PS I becomes large and thus the understanding of phenomena based on the model describing PS I in the state space becomes difficult. To understand the phenomena intuitively, we have reduced the complicated PS I model which has the multi-timescale property for electron and excitation-energy transfer processes into a simple one which has only the mono-timescale property through the use of hierarchical coarse-graining (HCG) method. The coarse-grained model describes the state of PS I by seven variable states, while the original model describes the PS I by 3 × 27(= 384) states. Based on the derived model, the I820(820 nm transmittance signal) curve in photosynthetic induction term, which indicates the accumulations of P700+and Pc+, is simulated and analyzed in comparison with experiment. With respect to this signal curve, it is revealed that the initial increase up to the shoulder at 10-3s, the increase from that point to the peak at 2 × 10-2s, and the decay after that peak reflect the accumulations of P700+, Pc+and P700FA-FB-(PS I state in which P700, FA-and FB-are observed.), respectively. Besides, the important role of the charge recombination processes from P700+A0A-and P700+A1A-states for the dissipation of the extra absorbed energy in photosynthetic induction period is confirmed.