Fundamental and applied studies of biological light-harvesting systems

我的研究重点是利用结合在生物光系统或光合作用反应中心(RC)中的特殊蛋白质和色素，捕捉太阳光并将其能量转化为电流的微生物。我的方法范围从寻找新物种到设计具有新生物物理特性的蛋白质，以及在将阳光转化为电能的生物光伏设备中的应用。加拿大致力于减少碳排放(www.ec.gc.ca)，在非核能、碳中性电力能源(太阳能、风能、生物质、水)中，太阳能潜力最大(比其他三种能源加起来大10倍)。由于我们对生物光系统的了解和新的基因工程方法的改进，生物光系统在光伏领域的应用已经成为可能，但我们仍然需要回答许多关于蛋白质中光子和电路的设计和创造的问题，以充分利用这些系统的潜力。 这项拟议的研究有两个目标：1)利用天然样品，发现并表征具有新特性的生物光系统；2)利用合成生物学，创造进出和通过作为电路一部分的蛋白质的新的电子路径。每个目标都将从另一个目标产生的新信息中受益。 1.为了获取自然样本，我们将：i)从自然环境中培育新物种；ii)从元基因组(从环境中收集的遗传物质)档案中提取基因。我们将使用我们获得的基因在我们的合成生物系统中创建活跃的光系统，该系统基于光合作用细菌球形红杆菌，它在中等温度(20-45摄氏度)下生长。具有新的物理化学性质的光系统将被用于设计生物光伏设备。目标是利用嗜热细菌的基因，因为它们的蛋白质应该能耐受高温(50-70摄氏度)，这种高温可能出现在太阳能应用中，比如屋顶上。 2.我们将开始与球藻的RC一起创造新的电通路，包括单独的和作为一个被捕光色素-蛋白质复合体包围的共复合体，在某些情况下，它提供耐热性。我们将改变蛋白质中特定位置的氨基酸，以阻断自然的电子转移途径，并将高压电力从RC转移到连接到电路的电极上。我们将测试色氨酸和酪氨酸残基是否可以用来在受激发的光色素和外部电路之间创建新的电子隧道路径。最初的目标是创造新的途径，利用球形乳杆菌蛋白提取电压升高的电流。稍后的工作将是研究在AIM 1中发现的嗜热菌的光系统。 我们的工作将创造新的知识，推进光伏技术，并为未来的研究和技术发展培养学生。

My research centres on microbes that capture solar light and convert its energy to electrical current, using special proteins and pigments combined in a biological photosystem or photosynthetic reaction centre (RC). My approach ranges from finding new species to engineering proteins with new biophysical properties, and applications in biophotovoltaic devices that convert sunlight to electricity. Canada is committed to reducing carbon emissions (www.ec.gc.ca) and of the non-nuclear, carbon-neutral electrical energy sources (solar, wind, biomass, water) solar has the greatest potential (order of 10-fold greater than the other three combined). The use of biological photosystems in photovoltaics has become possible due to our improved knowledge of these systems and new gene engineering methods, but we still need to answer many questions about the design and creation of photon and electrical circuits in proteins, to make full use of the potential of these systems. The proposed research has two Aims: 1) to discover and characterize biological photosystems with new properties, using natural samples; 2) to create novel electrical pathways into, out of, and through proteins that are part of an electrical circuit, using synthetic biology. Each aim will benefit from new information generated in the other. 1. To get natural samples we will: i) cultivate new species from natural environments; ii) extract genes from metagenome (genetic material collected from the environment) archives. We will use the genes we get to create active photosystems in our synthetic biology system, based on the photosynthetic bacterium Rhodobacter sphaeroides, which grows at moderate temperatures (20-45 C). Photosystems that have new physicochemical properties will be used to design biophotovoltaic devices. The goal is to use genes from thermophilic (heat loving) bacteria as their proteins should tolerate high temperatures (50-70 C) that might occur in solar energy applications such as on rooftops. 2. We will begin creating new electrical pathways with the RC of R. sphaeroides, both alone and as a co-complex encircled by a light-harvesting pigment-protein complex, which in some cases provides heat tolerance. We will change amino acids at specific sites in the protein to block the natural electron transfer pathway, and to divert high-voltage electricity from the RC to an electrode connected to a circuit. We will test if tryptophan and tyrosine residues may be used to create novel electron-tunnelling pathways between excited photopigments and an external electrical circuit. The initial goal is to create new pathways that extract electrical current of increased voltage using R. sphaeroides proteins. Later work will be on photosystems from thermophilic bacteria found in Aim 1. Our work will create new knowledge, advance photovoltaic technology, and train students for future careers in research and technology development.