Assembly and evolution of a photosynthetic antenna

光合作用是我们吃的所有食物的来源，也是我们使用的几乎所有能量的来源。这一过程利用阳光从大气中去除二氧化碳，并将其转化为碳水化合物，为地球提供食物。阳光被叶绿素色素捕获，这些色素被蛋白质排列并保持在适当的位置；这些色素-蛋白质排列被称为天线复合体。天线收集光能，并将其输送到专门的“反应中心”，在那里，能量被转化为细胞可以使用的形式。植物和蓝藻(蓝藻)使用叶绿素(Chl)色素来捕获可见光(400-700 nm)，进行“氧合”光合作用，释放支持呼吸的氧气。此外，各种各样的细菌也能够利用这个范围以外的光(700 Nm)，我们看不到的光，但感觉到是热，来进行‘产氧’光合作用。这种光合作用模式依赖于细菌叶绿素(BCHL)色素，而不是Chls。大多数缺氧光合作用分子使用Bchl a来收集750-900 nm之间的光，尽管红色红螺菌是一个被充分研究的例子，它通常不能有效地收集850 nm以下的光，因为它缺乏共同的天线复合体。该项目旨在将另一种光合作用细菌的天线转移到红色红螺菌，使这种新的杂交生物能够捕捉以前无法捕捉的光。对新细菌的进一步修改将通过对基因组进行有针对性的改变来进行，突变也将通过在光下生长生物来自然获得，这种光只能被新的天线复合体吸收，这一过程反映了自然进化，但可以在实验室中加速。实现这些目标将揭示如何在其他简单细菌中组装和调节色素-蛋白质复合体的产生，其长期目标是将增强的光捕捉能力用于以可持续的方式应对人类迫在眉睫的燃料和食品供应挑战。这也可能对气候变化产生积极影响；增加二氧化碳温室气体的清除，并将其转化为糖，可能会减缓地球变暖，并减轻对环境的破坏。

Photosynthesis is the source of all the food we eat, and almost all of the energy we use. This process uses sunlight to remove carbon dioxide from the atmosphere and convert it into carbohydrates that feed the planet. Sunlight is captured by chlorophyll pigments that are arranged and held in place by proteins; these pigment-protein arrangements are known as antenna complexes. Antennas collect the light energy and funnel it towards specialised 'reaction centres', where the energy is converted to a form that can be used by the cell.Plants and cyanobacteria (blue-green algae) use chlorophyll (Chl) pigments to capture visible light (400-700 nm) to perform 'oxygenic' photosynthesis, releasing the oxygen that supports respiration. Additionally, a diverse assortment of bacteria are also capable of using light outside this range (>700 nm), which we cannot see but feel as heat, to perform 'anoxygenic' photosynthesis. This mode of photosynthesis relies on the bacteriochlorophyll (BChl) pigments, rather than Chls.The majority of anoxygenic photosynthesisers use BChl a to harvest light between 750-900 nm, although Rhodospirillum rubrum is a well-studied example that unusually cannot harvest light effectively up to 850 nm because it lacks the common antenna complex. This project aims to transfer the antenna of another photosynthetic bacterium to Rhodospirillum rubrum, to allow the new, hybrid organism to capture light it was not previously able to.Further modifications to the new bacterium will be made by targeted alterations to the genome, and mutations will also be naturally acquired by growing the organism under light that can only be absorbed by the new antenna complex, a process that mirrors natural evolution, but that can be speeded-up in the laboratory.Achieving these aims will reveal how to assemble and regulate the production of pigment-protein complexes in other simple bacteria, with the long-term goal of putting boosted light-capturing ability to use to tackle some of humanity's impending fuel and food supply challenges in a sustainable manner. This could also have a positive effect on climate change; increased removal of CO2 greenhouse gas, and its conversion into sugars, could slow the warming of the planet, and mitigate the damage to the environment.