Controllable model membranes and new quantitative analyses to interrogate light harvesting proteins

本研究将开发新的模型系统和分析方法，以高时空分辨率量化重要的光收获（LH）蛋白的生物物理特性。这将使我们深入了解光合作用过程的物理基础，这一过程对地球上的生命至关重要，但人们对其知之甚少。它还将对LH蛋白在纳米技术、光子学和等离子体学中的潜在应用具有更广泛的相关性。我们需要开发一套“模型膜”（生物膜的理想实验模型），其中包含LH蛋白，并在复杂性，可控性和可适应的工具之间提供平衡，可以量化结构和光学性质。我们需要有能力控制这些模型膜内LH蛋白的密度。我们需要量化这些LH蛋白的组织和光学性质如何在重要的物理化学刺激下发生变化。该项目将开发三种用于LH蛋白研究的模型膜，这些模型膜将从大部分合成膜发展到接近天然膜。这些“模型膜”将首次通过施加外电场来操纵膜内LH蛋白的迁移。这些LH蛋白的纳米级组织和光物理性质将通过先进的显微镜和光谱组合系统在每种类型的膜中进行比较。我之前的研究表明，LH蛋白的聚类与能量耗散（荧光猝灭）有关，我对相关显微镜和光谱工具的专业知识使我非常适合进行能量传递过程的定量研究。在利兹，我们有一个新的荧光寿命成像显微镜与原子力显微镜（FLIM+AFM）仪器相结合，这将使光学性质和纳米级组织的直接关联和定量前所未有（我是获得该仪器的资助的共同研究者）。这种组合显微镜是研究LH蛋白的理想工具，给我们带来了竞争优势。总之，该项目将对新膜模型的优点和局限性进行比较分析，并在此过程中量化光收集蛋白的组织和光学性质之间的关键关系。这些新模型可以应用于与卫生和农业相关的细菌和哺乳动物膜。此外，了解重要的LHCII蛋白可能与开发替代太阳能纳米技术或生产增强型作物有关。

This proposal will develop new model systems and analysis methods to quantify the biophysical properties of important Light Harvesting (LH) proteins with high spatiotemporal resolution. This will provide insight into the physical basis of photosynthetic processes which are crucial for life on Earth but poorly understood. It will also have wider relevance for the potential use of LH proteins in nanotechnology, photonics and plasmonics. We need to develop a suite of "model membranes" (idealized experimental models of biomembranes) which incorporate LH proteins and offer a balance between complexity, controllability and amenability to tools that can quantify structure and optical properties. We need the ability to manipulate the density of LH proteins within these model membranes. We need to quantify how the organization and optical properties of these LH proteins change in response to important physicochemical stimuli. The proposed project will develop three types of model membranes for studying LH proteins, which progress from mostly synthetic to close-to-natural membranes. These "model membranes" will be manipulated by applying external electric fields to direct the migration of LH proteins within membranes, for the first time. The nanoscale organization and photophysical properties of these LH proteins will be compared in each type of membrane by an advanced microscopy and spectroscopy combined system. My previous research has demonstrated that the clustering of LH proteins is correlated to energy dissipation (fluorescence quenching) and my expertise with correlative microscopy and spectroscopy tools make me uniquely well-placed for performing quantitative studies of energy transfer processes. In Leeds, we have a new Fluorescence Lifetime Imaging Microscope combined with Atomic Force Microscopy (FLIM+AFM) instrument which will allow unprecedented direct correlation and quantification of optical properties and nanoscale organization (I was co-investigator on the grant acquiring this instrument). This combined microscope is ideal to study LH proteins and gives us a competitive edge. In summary, this project will provide a comparative analysis of the advantages and limitations of new membrane models and, in doing so, quantify the crucial relationship between organization and optical properties of light harvesting proteins. These new models could be applied to bacterial and mammalian membranes of relevance for health and agriculture. Furthermore, knowledge of the important LHCII protein could be relevant for the development of alternative solar nanotechnologies or the production of enhanced crops.