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光合作用光能的吸收、传递和转化是由位于光合膜上具有特定的分子排列和空间构象的色素蛋白复合物光系统Ⅱ(PSⅡ)和光系统Ⅰ(PSⅠ)所推动的.其中PSⅠ是一个具有极高效率的太阳能转化系统,其量子转化效率几乎为100%,但其高效吸能、传能和转能的结构基础尚不清楚.从高等植物碗豆的叶片提取了高纯度的光系统Ⅰ-捕光天线Ⅰ(PSⅠ-LHCⅠ)色素蛋白超分子复合物,并制备和解析了其2.8?的晶体结构[1].PSⅠ-LHCⅠ超分子复合物由16个蛋白亚基组成,总分子量约600 k D.本结构全面解析了高等植物PSⅠ-LHCⅠ的精细结构,揭示了PSⅠ-LHCⅠ的4个不同的捕光天线(Lhca1,Lhca2,Lhca3,Lhca4)在与PSⅠ核心复合物结合状态下的结构和它们的异同,以及它们之间的相互关系;揭示了LHCⅠ全新的色素网络系统,辨别了叶绿素a和b的不同位置,并阐明了4对红叶绿素(red Chls)和13个类胡萝卜素的结合位点和结构.根据所解析的结构,提出了由LHCⅠ向PSⅠ核心复合物能量传递的4条重要的可能途径.这些结果为揭示高等植物PSⅠ高效吸能、传能和转能的机理奠定了坚实的结构基础.本文将介绍所解析的高等植物PSⅠ-LHCⅠ的精细结构,并讨论PSⅠ-LHCⅠ能量传递机制.
The absorption, transfer and transformation of photosynthetic light energy are driven by the photosystem Ⅱ (PSⅡ) and the photosystemⅠ (PSⅠ) of the pigment protein complex which has a specific molecular arrangement and spatial conformation on the photosynthetic membrane, of which PSⅠ is a The highly efficient solar energy conversion system has a quantum conversion efficiency of almost 100%, but the structural basis for efficient energy absorption, energy transfer and energy transfer is not clear.High purity photoperiod system I was extracted from the leaves of higher plant peas - Light harvesting antenna Ⅰ (PSⅠ-LHCⅠ) pigment protein supramolecular complex, and its 2.8 Å crystal structure was prepared and analyzed.1 PSI-LHC Ⅰ supramolecular complex consists of 16 protein subunits with a total molecular weight of about 600 k D. This structure provides a comprehensive analysis of the fine structure of PSⅠ-LHCⅠ in higher plants and reveals that four different light-harvesting antennas (Lhca1, Lhca2, Lhca3, Lhca4) of PSⅠ-LHCⅠ bind to PSⅠ core complexes Structure and their similarities and differences, as well as the interrelationships between them; revealed a new LHCⅠpigment network system, discerned the different positions of chlorophyll a and b, and elucidated four pairs of red Chl and 13 carotenoids Of the binding sites And structure.According to the structure analyzed, four important possible ways of energy transfer from LHCⅠ to PSⅠ core complexes are proposed.These results provide a solid foundation for revealing the mechanism of PS Ⅰ efficient energy absorption, translocation and translocation Structural Basis. In this article, the fine structure of the PS I-LHC I in higher plants analyzed and the mechanism of PS I-LHC I energy delivery are discussed.