Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser.
Serial time-resolved crystallography of photosystem II using a femtosecond X-ray laser.
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使用飞秒X射线激光器的光系统II的串行时间分辨晶体学。
DOI：
10.1038/nature13453
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发表时间：
2014-09-11
期刊：
影响因子：
64.8
通讯作者：
Fromme P
中科院分区：
文献类型：
--
作者：
Kupitz C;Basu S;Grotjohann I;Fromme R;Zatsepin NA;Rendek KN;Hunter MS;Shoeman RL;White TA;Wang D;James D;Yang JH;Cobb DE;Reeder B;Sierra RG;Liu H;Barty A;Aquila AL;Deponte D;Kirian RA;Bari S;Bergkamp JJ;Beyerlein KR;Bogan MJ;Caleman C;Chao TC;Conrad CE;Davis KM;Fleckenstein H;Galli L;Hau-Riege SP;Kassemeyer S;Laksmono H;Liang M;Lomb L;Marchesini S;Martin AV;Messerschmidt M;Milathianaki D;Nass K;Ros A;Roy-Chowdhury S;Schmidt K;Seibert M;Steinbrener J;Stellato F;Yan L;Yoon C;Moore TA;Moore AL;Pushkar Y;Williams GJ;Boutet S;Doak RB;Weierstall U;Frank M;Chapman HN;Spence JC;Fromme P
光合作用是由植物、藻类和蓝细菌催化的过程，它将阳光转化为能量，从而维持地球上所有高等生物的生存。两个大的膜蛋白复合物，光系统I和II（PSI和PSII），串联起催化光合作用中的光驱动反应的作用。PSII催化光驱动的水分解过程，维持地球的含氧大气。在这个过程中，PSII的放氧复合物（OEC）循环通过五个状态，S 0到S4，其中四个电子在四个光驱动的电荷分离事件中依次从OEC中提取。在这里，我们描述的时间分辨实验PSII纳米/微晶从细长热聚球藻进行了最近开发的技术，串行飞秒晶体学。已分别以5 Å和5.5 Å的分辨率从PSII在暗S1态和双激光激发（推定的S3态）后确定了结构。结果提供的证据表明，PSII经历了显着的构象变化，在电子受体侧和Mn 4CaO 5核心的OEC。这些包括金属簇的伸长，伴随着蛋白质环境的变化，这可以允许在S2到S3过渡中更远的突出Mn（称为“悬垂"Mn）和Mn 3CaOx立方烷之间的第二底物水分子的结合，如光谱和计算研究所预测的。这项工作显示了时间分辨连续飞秒晶体学在生物分子催化过程研究中的巨大潜力。
Photosynthesis, a process catalysed by plants, algae and cyanobacteria converts sunlight to energy thus sustaining all higher life on Earth. Two large membrane protein complexes, photosystem I and II (PSI and PSII), act in series to catalyse the light-driven reactions in photosynthesis. PSII catalyses the light-driven water splitting process, which maintains the Earth’s oxygenic atmosphere. In this process, the oxygen-evolving complex (OEC) of PSII cycles through five states, S0 to S4, in which four electrons are sequentially extracted from the OEC in four light-driven charge-separation events. Here we describe time resolved experiments on PSII nano/microcrystals from Thermosynechococcus elongatus performed with the recently developed technique of serial femtosecond crystallography. Structures have been determined from PSII in the dark S1 state and after double laser excitation (putative S3 state) at 5 and 5.5 Å resolution, respectively. The results provide evidence that PSII undergoes significant conformational changes at the electron acceptor side and at the Mn4CaO5 core of the OEC. These include an elongation of the metal cluster, accompanied by changes in the protein environment, which could allow for binding of the second substrate water molecule between the more distant protruding Mn (referred to as the ‘dangler’ Mn) and the Mn3CaOx cubane in the S2 to S3 transition, as predicted by spectroscopic and computational studies. This work shows the great potential for time-resolved serial femtosecond crystallography for investigation of catalytic processes in biomolecules.