高等植物光系统II的外周捕光天线系统主要由四种结合色素的膜蛋白：主要捕光复合物LHCII和次要捕光复合物CP24、CP26、CP29共同组成。这些天线蛋白协同作用，在正常光照条件下确保光能被高效吸收并传递到反应中心；在强光条件下则将过多的光能以热的形式耗散掉(也称NPQ)。阐明这些不同天线蛋白的三维结构以及它们之间的相互配置信息，是探讨光合作用机制、了解捕光天线是如何在两种不同的功能之间进行转换的重要基础。目前除LHCII和CP29外，还没有其它天线蛋白的结构被报道。本课题拟以高等植物光系统II中的CP24、CP26等多个捕光蛋白色素复合物为研究对象，从植物叶片中提取光合膜蛋白样品，进行结晶和结构研究；并基于这些捕光天线蛋白的三维结构以及其色素的组成排布信息，结合相关的功能实验，探讨光能高效吸收、传递的途径和机制以及植物的光保护机制等重要学术问题。

The peripheral antenna system of higher plant photosystem II (PSII) mainly consists of four different types of protein-pigment complexes embedded in the thylakoid membrane: the major light harvesting complex LHCII and the minor light harvesting complexes: CP24, CP26 and CP29. These antenna proteins cooperate with each other to ensure the efficient light harvesting and transferring to the reaction center under normal light conditions. While under high light conditions, they function in photo-protection to dissipate excess excitation energy as heat protecting plants from photo-damage (known as NPQ). Structural information about these antenna complexes as well as the information of their mutual orientation and location is important for an improved understanding of the energy transfer process and their regulatory mechanism. So far, crystal structures of LHCII and CP29 from higher plants are available, whereas structural information on other minor light-harvesting complexes is still lacking. This research project focuses on structural and functional analysis of PSII peripheral antenna proteins (such as CP24, CP26 etc.) from higher plants, isolating and purifying these photosynthesis membrane proteins from higher plant leaves, then performing crystallization screens and structural determination of these proteins. The information of the protein structures as well as their pigments composition and arrangement, combining with biochemical and spectroscopic results, may help us to elucidate the mechanisms of efficient light-energy absorption and transition, photo-protection and other important functions related to the photosynthesis.