Photosynthetic Vesicle Architecture and Constraints on Efficient Energy Harvesting
Photosynthetic Vesicle Architecture and Constraints on Efficient Energy Harvesting
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DOI：
10.1016/j.bpj.2010.04.013
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发表时间：
2010-07-07
影响因子：
3.4
通讯作者：
Schulten, Klaus
中科院分区：
文献类型：
--
作者：
Sener, Melih;Struempfer, Johan;Schulten, Klaus
在一些紫色细菌中发现的光合色素囊泡构成了自然界中最简单的捕光系统之一。色素囊泡的整体架构和囊泡功能的结构整合仍然知之甚少，尽管结构信息可在个别组成蛋白。一个全原子结构模型的整个色素囊泡，它改进了早期的模型，考虑到化学计量的核心和天线复合物的完整囊泡在球形红细菌的吸收光谱，以及完善的曲率诱导性能的二聚核心复合物。低光适应囊泡的吸收光谱显示对应于捕光复合物2与反应中心的比例为3：1。与此化学计量一致的囊泡的结构模型的开发和用于激子性质的计算。还考虑了天线和核心复合物的堆积密度，该堆积密度足够高以进行有效的能量转移，并且足够低以使醌从反应中心扩散到细胞色素bc（1）复合物。
Photosynthetic chromatophore vesicles found in some purple bacteria constitute one of the simplest light-harvesting systems in nature. The overall architecture of chromatophore vesicles and the structural integration of vesicle function remain poorly understood despite structural information being available on individual constituent proteins. An all-atom structural model for an entire chromatophore vesicle is presented, which improves upon earlier models by taking into account the stoichiometry of core and antenna complexes determined by the absorption spectrum of intact vesicles in Rhodobacter sphaeroides, as well as the well-established curvature-inducing properties of the dimeric core complex. The absorption spectrum of low-light-adapted vesicles is shown to correspond to a light-harvesting-complex 2 to reaction center ratio of 3:1. A structural model for a vesicle consistent with this stoichiometry is developed and used in the computation of excitonic properties. Considered also is the packing density of antenna and core complexes that is high enough for efficient energy transfer and low enough for quinone diffusion from reaction centers to cytochrome bc(1) complexes.