Projection structure of the photosynthetic reaction centre-antenna complex of Rhodospirillum rubrum at 8.5 Å resolution
Projection structure of the photosynthetic reaction centre-antenna complex of Rhodospirillum rubrum at 8.5 Å resolution
复制标题
DOI：
10.1093/emboj/cdf410
复制
发表时间：
2002-08-01
期刊：
影响因子：
11.4
通讯作者：
Bullough, PA
中科院分区：
文献类型：
--
作者：
Jamieson, SJ;Wang, PY;Bullough, PA
用洗涤剂溶解和纯化的蛋白质复合物形成了紫色无硫细菌红红螺旋菌反应中心集光配合物I （RC-LH1）的二维晶体。这种内在膜蛋白复合物的未染色样品已通过电子冷冻显微镜进行了分析。(低温EM)。从两种不同的晶体形式计算出8.5埃的投影图，并显示出一个由16个LH1亚基包围的单一反应中心，其直径约为115埃。在每个LH1亚基中，α -和β -多肽链的密度是明确确定的。在一种晶体形式中，LH1形成圆形环，而在另一种晶体形式中，环明显呈椭球形。在每种情况下，反应中心都采用首选取向，这表明反应中心与LH1亚基之间存在特定的相互作用，而不是与天线环的可能取向的连续体。这个实验确定的结构表明在封闭的LH1环中没有任何其他蛋白质成分的证据。圆形或椭圆形式的LH1表明该复合物可能在细菌膜中具有柔韧性。
Two-dimensional crystals of the reaction-centre-light-harvesting complex I (RC-LH1) of the purple nonsulfur bacterium Rhodospirillum rubrum have been formed from detergent-solubilized and purified protein complexes. Unstained samples of this intrinsic membrane protein complex have been analysed by electron cryomicroscopy.(cryo EM). Projection maps were calculated to 8.5 Angstrom from two different crystal forms, and show a single reaction centre surrounded by 16 LH1 subunits in a ring of similar to115 Angstrom diameter. Within each LH1 subunit, densities for the alpha- and beta-polypeptide chains are clearly resolved. In one crystal form the LH1 forms a circular ring, and in the other form the ring is significantly ellipsoidal. In each case, the reaction centre adopts preferred orientations, suggesting specific interactions between the reaction centre and LH1 subunits rather than a continuum of possible orientations with the antenna ring. This experimentally determined structure shows no evidence of any other protein components in the closed LH1 ring. The demonstration of circular or elliptical forms of LH1 indicates that this complex is likely to he flexible in the bacterial membrane.