Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7-Å resolution
Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3.7-Å resolution
复制标题
DOI：
10.1073/pnas.0135651100
复制
发表时间：
2003-01-07
影响因子：
11.1
通讯作者：
Shen, JR
中科院分区：
文献类型：
--
作者：
Kamiya, N;Shen, JR
光系统II（PSII）是一种多亚基膜蛋白复合物，进行光诱导的电子转移和水裂解反应，导致分子氧的形成。最近报道了来自嗜热蓝细菌Thermosynechococcus elongatus的PSII的第一个晶体结构[Zouni，A.，Witt，H. T.，克恩，J.，Fromme，P.，克劳斯，N.，Saenger，W.和Orth，P.（2001）Nature 409，739-743）]。为了更详细地分析PSII的结构，我们从另一种嗜热蓝细菌Thermosynechococcus vulcanus中获得了PSII的晶体结构，分辨率为3.7埃。目前的结构是建立在PSII大亚基D1，D2，CP 47和CP 43的序列的基础上，外来的33-和12-kDa的蛋白质和细胞色素c550，和几个低分子量的亚基，其中12-kDa的蛋白质的结构是以前没有报道。这产生了许多关于这个大蛋白质复合物内分子相互作用的信息。我们还显示了叶绿素和辅因子的排列，包括最近在靠近反应中心的区域中发现的两种β-胡萝卜素，这为反应中心周围的二次电子转移途径提供了重要线索。此外，可能的配体的锰簇被确定。特别地，D1多肽的C末端显示直接连接到Mn簇。这里获得的结构信息提供了重要的见解PSII反应的机制。
Photosystem II (PSII) is a multisubunit membrane protein complex performing light-induced electron transfer and water-splitting reactions, leading to the formation of molecular oxygen. The first crystal structure of PSII from a thermophilic cyanobacterium Thermosynechococcus elongatus was reported recently [Zouni, A., Witt, H. T., Kern, J., Fromme, P., Krauss, N., Saenger, W. & Orth, P. (2001) Nature 409, 739-743)] at 3.8-Angstrom resolution. To analyze the PSII structure in more detail, we have obtained the crystal structure of PSII from another thermophilic cyanobacterium, Thermosynechococcus vulcanus, at 3.7-Angstrom resolution. The present structure was built on the basis of the sequences of PSII large subunits D1, D2, CP47, and CP43; extrinsic 33- and 12-kDa proteins and cytochrome c550; and several low molecular mass subunits, among which the structure of the 12-kDa protein was not reported previously. This yielded much information concerning the molecular interactions within this large protein complex. We also show the arrangement of chlorophylls and cofactors, including two beta-carotenes recently identified in a region close to the reaction center, which provided important clues to the secondary electron transfer pathways around the reaction center. Furthermore, possible ligands for the Mn-cluster were determined. In particular, the C terminus of D1 polypeptide was shown to be connected to the Mn cluster directly. The structural information obtained here provides important insights into the mechanism of PSII reactions.