Karrasch S, Bullough P A, Ghosh R
MRC Laboratory of Molecular Biology, Cambridge, UK.
EMBO J. 1995 Feb 15;14(4):631-8. doi: 10.1002/j.1460-2075.1995.tb07041.x.
Two-dimensional crystals from light-harvesting complex I (LHC I) of the purple non-sulfur bacterium Rhodospirillum rubrum have been reconstituted from detergent-solubilized protein complexes. Frozen-hydrated samples have been analysed by electron microscopy. The crystals diffract beyond 8 A and a projection map was calculated to 8.5 A. The projection map shows 16 subunits in a 116 A diameter ring with a 68 A hole in the centre. These dimensions are sufficient to incorporate a reaction centre in vivo. Within each subunit, density for the alpha- and the beta-polypeptide chains is clearly resolved, and the density for the bacteriochlorophylls can be assigned. The experimentally determined structure contradicts models of the LHC I presented so far.
来自紫色非硫细菌红螺菌光合捕光复合体I(LHC I)的二维晶体已从去污剂溶解的蛋白质复合物中重构出来。冷冻水合样品已通过电子显微镜进行分析。这些晶体的衍射分辨率超过8 Å,并计算出了8.5 Å的投影图。投影图显示,在直径为116 Å的环中有16个亚基,中心有一个68 Å的孔。这些尺寸足以在体内纳入一个反应中心。在每个亚基内,可以清楚地分辨出α-和β-多肽链的密度,并且可以确定细菌叶绿素的密度。实验确定的结构与迄今为止提出的LHC I模型相矛盾。