Single molecule studies on purple bacterial antenna complexes

光合作用开始于天线色素对太阳能的吸收。然后，这些吸收的能量被快速有效地转移到反应中心，在那里被捕获并用于驱动光合作用。因此，光捕获是这个非常重要的生物过程的基本组成部分，最终提供我们吃的所有食物，我们呼吸的氧气，并通过去除二氧化碳来清洁空气。该提案旨在使用X射线晶体学和单分子光谱学的组合来研究从紫色光合细菌中获得的捕光天线复合物的物理和电子结构。这些细菌已被证明是研究光合作用最早反应中发生的基本反应的极好模型系统。普通光谱学研究的是大量分子的性质，即所谓的系综光谱学。然而，因为这平均了所有存在的分子，并且因为每个分子不相同，所以许多重要的细节被平均掉并丢失。观察单个分子可以观察到这些细节，在这种情况下，如果我们希望了解天线复合物的功能，它们是必不可少的。在这方面，单分子光谱学是一个独特的重要工具。

Photosynthesis begins with the absorption of solar energy by antenna pigments. This absorbed energy is then rapidly and efficiently transferred to reaction centres where it is trapped and used to drive photosynthesis. Light-harvesting is therefore and essential and fundamental part of this very important biological process that ultimately provides all the food we eat, the oxygen we breathe and cleans the air by removing carbon dioxide. This proposal aims to use a combination of X-ray crystallography and single molecule spectroscopy to study both the physical and electronic structure of a group on light-harvesting antenna complexes obtained from purple photosynthetic bacteria. These bacteria have proved to be excellent model systems in which to study the fundamental reactions going on in the earliest reaction of photosynthesis. Normal spectroscopy looks at the properties of large populations of molecules, so-called ensemble spectroscopies. However because this averages over all the molecules present and because each molecule is not identical many important details are averaged out and lost. Looking at individual molecules allows these details to be observed and they are, in this case with the antenna complexes, essential if we wish to understand how antenna complexes function. In this regard single molecule spectroscopy is a uniquely important tool.