Understanding the role of carotenoids in bacterial light-harvesting proteins

该项目将量化“采光”蛋白质如何保护光合作用有机体免受强烈阳光照射，这一过程被称为“光保护”。为了做到这一点，我们将使用我们团队最近开发的黄体生成素蛋白和人造生物膜的转基因版本。这些黄体生成素蛋白自然地定位于光合作用细菌或植物叶绿体中发现的特殊生物膜中。强烈的阳光会对植物和光合作用细菌造成损害，因此，为了防止这种情况，它们会启动光保护过程，安全地移除多余的能量。这一过程对于植物和光营养细菌的适合性是必不可少的，但我们对此的了解还存在空白。我们知道与胡萝卜素类色素有关，也知道黄体生成素蛋白的聚集增加了能量消耗，但分子细节尚不确定。这个项目将通过比较来自光合作用细菌的黄体生成素蛋白和来自植物的黄体生成素蛋白来确定这两个因素(类胡萝卜素和蛋白质聚集)如何引起光保护。样品将使用世界级的显微镜和光谱分析仪器套件进行分析。首先，在最简单的分离蛋白情况下，我们将评估黄体生成素蛋白中的能量消耗与其类胡萝卜素含量之间的关系。其次，我们将使用人造生物膜评估能量消耗如何与蛋白质聚集和类胡萝卜素的双重影响有关，人造生物膜为我们提供了对系统更好的控制。第三，我们将评估天然生物膜，并将其与人造生物膜进行比较，以表明更复杂的自然系统是否有其他因素改变黄体生成素蛋白的行为。揭示植物和细菌如何控制LH膜内能量分配的共同分子机制将有助于我们理解太阳能捕获的关键阶段，这些阶段是全球光合作用过程的基础。这可能会提供新的信息，帮助其他研究人员开发产量更高的改良作物。

This project will quantify how "light-harvesting" (LH) proteins can protect photosynthetic organisms from exposure to intense sunlight, in a process called "photo-protection". To do this, we will use genetically-modified versions of the LH proteins and artificial biomembranes that were recently developed by our team. These LH proteins are naturally localised within specialised biomembranes found in photosynthetic bacteria or plant chloroplasts. Bright sunlight can cause damage to plants and photosynthetic bacteria, so, to prevent this they activate photo-protective processes which safely remove the excess energy. This process is essential for fitness of plants and phototrophic bacteria but there are gaps in our knowledge of it. We know that carotenoid pigments are involved and also that the clustering of LH proteins increases energy dissipation, but the molecular details are uncertain. This project will determine how these two factors (carotenoids and protein clustering) can cause photo-protection by comparing LH proteins from photosynthetic bacteria to LH proteins from plants. Samples will be analysed with a world-class suite of microscopy and spectroscopy instruments. Firstly, we will assess how energy dissipation in the LH proteins is related to their carotenoid content for the simplest situation of isolated proteins. Secondly, we will assess how energy dissipation relates to the dual effects of protein clustering and carotenoids using artificial biomembranes which offer us greater control over the system. Thirdly, we will assess natural biomembranes and compare these to the artificial biomembranes to show whether the more complicated native system has other factors which alter the behaviour of LH proteins. Revealing the shared molecular mechanisms for how plants and bacteria control the distribution of energy within LH membranes will help us to understand the critical stages of solar energy capture which are fundamental to the global process of photosynthesis. This could provide new information that helps other researchers develop improved crops that have higher yields.