Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands,
Photosynth Res. 2013 Oct;116(2-3):153-66. doi: 10.1007/s11120-013-9838-x. Epub 2013 May 4.
This review focuses on the light-harvesting properties of photosystem I (PSI) and its LHCI outer antenna. LHCI consists of different chlorophyll a/b binding proteins called Lhca's, surrounding the core of PSI. In total, the PSI-LHCI complex of higher plants contains 173 chlorophyll molecules, most of which are there to harvest sunlight energy and to transfer the created excitation energy to the reaction center (RC) where it is used for charge separation. The efficiency of the complex is based on the capacity to deliver this energy to the RC as fast as possible, to minimize energy losses. The performance of PSI in this respect is remarkable: on average it takes around 50 ps for the excitation to reach the RC in plants, without being quenched in the meantime. This means that the internal quantum efficiency is close to 100% which makes PSI the most efficient energy converter in nature. In this review, we describe the light-harvesting properties of the complex in relation to protein and pigment organization/composition, and we discuss the important parameters that assure its very high quantum efficiency. Excitation energy transfer and trapping in the core and/or Lhcas, as well as in the supercomplexes PSI-LHCI and PSI-LHCI-LHCII are described in detail with the aim of giving an overview of the functional behavior of these complexes.
本综述重点介绍了光系统 I（PSI）及其 LHCI 外部天线的光捕获特性。LHCI 由不同的叶绿素 a/b 结合蛋白（称为 Lhca）组成，围绕 PSI 的核心。高等植物的 PSI-LHCI 复合物总共含有 173 个叶绿素分子，其中大部分用于收集太阳光能，并将产生的激发能转移到反应中心（RC），用于电荷分离。复合物的效率基于尽快将能量传递到 RC 的能力，以最小化能量损失。在这方面，PSI 的性能非常出色：在植物中，激发到达 RC 平均需要大约 50 皮秒的时间，而不会在此期间被猝灭。这意味着内部量子效率接近 100%，这使得 PSI 成为自然界中最有效的能量转换器。在本综述中，我们描述了该复合物的光捕获特性与其蛋白质和色素的组织/组成之间的关系，并讨论了确保其非常高的量子效率的重要参数。详细描述了核心和/或 Lhcas 中的激发能量转移和捕获，以及 PSI-LHCI 和 PSI-LHCI-LHCII 超复合物中的激发能量转移和捕获，旨在概述这些复合物的功能行为。
