Building Solar-Powered, Carbon-Fixing Protoalgae

藻类是单细胞生物，它们利用阳光进行新陈代谢，并将大气中的二氧化碳转化为有用的碳水化合物。像植物一样，它们有复杂的光合作用机制，可以有效地捕获光能并将其转化为生物电。这种电流通过嵌入在蛋白质中的电路流动，蛋白质是由线性氨基酸链构成的生物分子，采用复杂的三维结构，由它们的氨基酸序列决定。这些蛋白质中还含有其他类型的生物衍生分子，这些分子赋予捕获光和形成电路所需的特定功能。既然我们现在在原子水平上对光合作用机制有了很好的理解，就有可能考虑这个过程中的关键步骤，并将它们整合到全新的人造蛋白质或重新设计的天然蛋白质中；因此，光合作用过程可以在更简单的、按比例缩小的系统中重现。因此，我们选择了人造蛋白质和天然蛋白质作为人工光合作用途径的功能性构建块，这将使我们不仅可以操作简单的光合作用过程，而且还可以将其封装在称为原始细胞的基本细胞样组装中。这些实体的设计是为了方便功能性生物和人工成分在一个非常简单的隔间中输入，就像一个活的细菌细胞。目前，由于这些原始细胞的信息存储能力有限或没有，它们不能进化或主动繁殖，它们作为一个安全的平台，让我们测试我们对复杂生物分子和系统的理解，同时让我们探索地球上生命起源的各个方面。原始细胞还可以对蛋白质等生物分子产生不同寻常的影响，增加酶（能够进行化学反应的蛋白质）的速率，并提供蛋白质和酶进化环境的有用摹本。因此，我们不仅打算构建功能性的人造光合作用组件，而且还打算将这些组件与能够将二氧化碳转化为有用化学构建块的天然酶共同封装在原始细胞中。这将提供一种原始但用途广泛的太阳能“原生藻类”，可以在其上构建更复杂的新陈代谢。除了通过这项工作可以实现的生物系统和分子的学术研究之外，提供可编程细胞样实体也有很大的潜力，可以执行大规模工业过程中无法实现的真正有用的化学反应。因此，我们坚信这项工作对于生物工程的基础探索和解决工业问题的原始细胞的构建都是有意义的。

Algae are single-celled organisms that use sunlight to power their metabolism and convert atmospheric carbon dioxide into useful carbohydrates. Like plants, they have a sophisticated photosynthetic machinery that has evolved to efficiently capture light energy and convert it into a type of biological electricity. This electricity flows through circuits that are embedded in proteins - biological molecules built from linear chains of amino acids that adopt complex 3D structures informed by their amino acid sequence. These proteins also contain within them other types of biologically derived molecules that impart specific functions necessary for capturing light and forming electrical circuits. Since we now have a good, working understanding of the photosynthetic machinery at the atomic level, it is possible to consider the key steps in this process and incorporate them into entirely new, manmade proteins or redesigned natural proteins; thus, the photosynthetic process could be recapitulated in much simpler, scaled-down systems. We have therefore selected both manmade and natural proteins to act as functional building blocks in an artificial photosynthetic pathway that will allow us not only to operate a simple photosynthetic process, but also to encapsulated it within an elementary cell-like assembly called a protocell. These entities are designed to facilitate the input of functional biological and artificial components in a very simple compartment, much like a living bacterial cell. Currently, since there is limited or no information storage capacity in these protocells, they cannot evolve or actively reproduce and they act as a safe platform for us to test our understanding of complex biological molecules and systems, while allowing us to explore aspects of the origin of life on Earth. Protocells can also exhibit unusual influences on biological molecules like proteins, increasing the rates of enzymes - proteins capable of performing chemical reactions - and providing a useful facsimile of the environment in which proteins and enzymes evolved. We therefore intend not only to build functional, manmade photosynthetic assemblies, but also to co-encapsulate these in a protocell with a natural enzyme capable of transforming carbon dioxide into a useful chemical building block. This will provide a primitive but versatile, solar-powered 'protoalgae' into which a more sophisticated metabolism can be constructed. Beyond the academic study of biological systems and molecules that can be achieved through this work, there is also great potential to deliver programmable cell-like entities that can perform truly useful chemistry unachievable in large-scale industrial process. Therefore, we strongly believe this work to be of interest both for the fundamental exploration of biological engineering and for the construction of protocells for addressing industrial issues.