Structure and Function of the Prochlorothrix Hollandica Photosynthetic Antenna System

光合作用的原核生物荷兰原绿思菌（Prochlorothrix hollandica）是已知的唯一含有高等植物天线色素叶绿素b的自由生活细菌。这一特征引发了许多比较研究，以确定荷兰原绿思菌的天线在结构和功能上是否与高等植物的天线相似。其他实验室先前的研究表明，荷兰p.h lanica中也存在类囊体膜堆叠，这一功能归因于绿色植物叶绿体的LHCII天线。由于荷兰p.h lanica Chl a/b天线在结构上比叶绿体LHCII更简单，本研究对荷兰p.h lanica的天线蛋白进行研究，以探究其膜堆叠的结构基础。实验方法结合分子生物学、生物化学和生物物理技术，解决以下具体问题：1)附属chl蛋白之间的进化关系是什么？2)光合生物如何适应不断变化的光照条件？3)类囊体膜堆积的结构要求是什么？进化氧光合作用的光反应涉及两种膜结合的色素结合复合物，一种参与初级光化学反应，另一种通过收集光能将其传递给初级系统而起辅助天线作用。​近年来，人们对叶绿素蛋白有了大量的了解。相比之下，许多天线复合体的结构是不知道这种高水平的分辨率。本研究的重点是研究一类原核天线叶绿素蛋白，以帮助了解它们的合成、组装及其与叶绿体天线系统的关系

The photosynthetic prokaryote, Prochlorothrix hollandica, is the only free-living bacterium known which contains the higher plant antenna pigment chlorophyll b. This feature has initiated many comparative studies examining whether the P. hollandica antenna is structurally and functionally similar to that of higher plants. Previous studies from other laboratories have shown that thylakoid membrane stacking occurs in P. hollandica, a function ascribed to the LHCII antenna of green plant chloroplasts. Since the P. hollandica Chl a/b antenna is structurally simpler than chloroplast LHCII, this research studies the antenna proteins of P. hollandica to probe the structural basis for membrane stacking. The experimental approach combines molecular biological, biochemical and biophysical techniques to address the following specific questions: 1) What are the evolutionary relationships among accessory Chl-proteins?; 2) How do photosynthetic organisms adapt to changing light conditions?; and 3) What are the structural requirements for thylakoid membrane stacking?%%% The light reactions of oxygen evolving photosynthesis involve two kinds of membrane-bound pigment-binding complexes,those which are involved in the primary photochemistry and those which serve an accessory antenna function by harvesting light energy to be transferred to the primary systems. A great deal of information has been recently obtained about the chlorophyll-proteins. In contrast, the structure of many antenna complexes is not known to this high level of resolution. The focus of this research is to examine a class of prokaryotic antenna chlorophyll-proteins to help understand their synthesis, assembly and relatedness to chloroplast antennae systems.***