被稱為“光系統(tǒng)-I”的蛋白超級復合物在聚集能量方面是一個“明星”：它是自然界最高效的光—化學機器，它所吸收的幾乎每個光子都被用來驅(qū)動電子的傳輸,；而且作為植物,、綠藻和藻青菌中普遍存在的光聚集器官,，它為地球上幾乎所有高等生物提供能量。現(xiàn)在,，植物“光系統(tǒng)-I”的X-射線晶體結(jié)構(gòu)已經(jīng)以3.4?魡的分辨率被確定，從而顯示了這種超高效率背后所存在的高度復雜性,。從豌豆植物中分離出來的該復合物包含17個蛋白亞單元,、168個葉綠素分子、2個葉綠醌分子,、3個Fe4S4簇和5個類胡蘿卜素分子,。
英文原文：
Nature 447, 58-63 (3 May 2007) | doi:10.1038/nature05687; Received 1 December 2006; Accepted 19 February 2007
The structure of a plant photosystem I supercomplex at 3.4 Å resolution
Alexey Amunts1, Omri Drory1 & Nathan Nelson1
Department of Biochemistry, The George S. Wise Faculty of Life Sciences, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Tel Aviv, 69978, Israel
Correspondence to: Nathan Nelson1 Correspondence and requests for materials should be addressed to N.N. (Email: [email protected]).
Top of page
Abstract
All higher organisms on Earth receive energy directly or indirectly from oxygenic photosynthesis performed by plants, green algae and cyanobacteria. Photosystem I (PSI) is a supercomplex of a reaction centre and light-harvesting complexes. It generates the most negative redox potential in nature, and thus largely determines the global amount of enthalpy in living systems. We report the structure of plant PSI at 3.4 Å resolution, revealing 17 protein subunits. PsaN was identified in the luminal side of the supercomplex, and most of the amino acids in the reaction centre were traced. The crystal structure of PSI provides a picture at near atomic detail of 11 out of 12 protein subunits of the reaction centre. At this level, 168 chlorophylls (65 assigned with orientations for Qx and Qy transition dipole moments), 2 phylloquinones, 3 Fe4S4 clusters and 5 carotenoids are described. This structural information extends the understanding of the most efficient nano-photochemical machine in nature.
