From Comparative Genomics to Photosynthetic Function

光合作用是一个惊人的动态过程，可以迅速调整到环境变化和细胞的发展。光合作用活性的调节对于协调细胞生长、发育过程和环境条件与能量、还原剂和固定碳（例如糖）的光合生产至关重要。光合作用的动态特征包括蛋白质和色素修饰以及可能需要数毫秒的构象调整，以及可能需要数分钟至数小时的光合机制的更广泛的重塑。在我们的知识中仍然有很大的差距，协调光合作用活动与环境变化和发展过程的机制。该项目的重点是识别和表征一组相对较小的蛋白质中的突变体，这些蛋白质与绿色植物/藻类谱系相关，但不存在于不进行光合作用的生物体中。该蛋白质组的许多成员被称为“GreenCut”（Merchant等人，Science 2007），似乎对叶绿体中发生的活动至关重要，但没有确定的功能。将使用GreenCut蛋白缺陷的既存衣原体（绿色，单细胞衣原体）突变体进行实验，然后生成额外的GreenCut突变菌株;将在生物物理和生物化学水平对这些菌株进行彻底表征。这项工作将对许多研究领域产生重大的智力影响：它将（1）赋予功能未知但与植物和藻类绿色谱系相关的蛋白质功能，并且最有可能具有与叶绿体功能相关的某些活性（直接或间接）;（2）允许更好地了解光合动力学及其如何调节;（3）初步了解光合作用成分的演变以及它们在不同藻类和植物群体中的分化方式。了解光合动力学可能会为生态系统生物学提供新的见解，其中许多正在遭受严重的退化（例如，珊瑚礁的消亡与藻类光合作用电子传递的恶化有关，藻类生活在珊瑚的动物部分内，为珊瑚提供固定碳）。从广义上讲，该项目的深入发展将使人们更好地了解光合生物与其环境的界面，从而使研究人员能够更好地管理地球上的各种生态系统。这方面的研究还促进了一门名为“光合作用：从基本机制到生物燃料”的本科课程的发展，该课程目前正在斯坦福大学教授，并导致培养博士后研究员、本科生和研究生。最后，该项目促进了国家和国际合作;与著名的实验室合作。

Intellectual Merit: Photosynthesis is an astoundingly dynamic process that can be rapidly tuned to environmental change and the development of cells. The tuning of photosynthetic activity is critical for coordinating cellular growth, developmental processes, and environmental conditions with the photosynthetic production of energy, reductants, and fixed carbon (e.g. sugars). Dynamic features of photosynthesis include protein and pigment modifications and conformational adjustments that can take milliseconds, to more extensive remodeling of the photosynthetic machinery that can take from minutes to hours. There are still large gaps in our knowledge concerning mechanisms that coordinate photosynthetic activity with environmental change and developmental processes. This project is focused on identifying and characterizing mutants in a relatively small set of proteins that have been associated with the green plant/algal lineages, but are not present in organisms that do not perform photosynthesis. Many members of this protein set, which is designated the "GreenCut"(Merchant et al., Science 2007), appear to be critical for activities that occur in chloroplasts, but have no established function. Experiments will be performed with pre-existing Chlamydomonas (green, unicellular alga) mutants defective for GreenCut proteins, followed by the generation of additional GreenCut mutant strains; these strains will be thoroughly characterized at the biophysical and biochemical levels. This work will have significant intellectual impact with respect to a number of research areas: It will (1) confer functionality on proteins that have no known function but that are associated with the plant and algal green lineages, and that most likely have some activity associated with chloroplast function (directly or indirectly); (2) allow for a better understanding of photosynthetic dynamics and how they are regulated; (3) generate an initial view of the evolution of photosynthetic components and the ways in which they have diverged in the different algal and plant groups.Broader Impact: Understanding photosynthetic dynamics is likely to provide new insights into ecosystem biology, many of which are suffering severe degradation (e.g. the demise of coral reefs is linked to the deterioration of photosynthetic electron transport in the algae that lives inside the animal component of the coral and provides it with fixed carbon). In a broad sense, an in-depth development of this project will generate a better understanding of the interface of photosynthetic organisms with their environment, which in turn will allow researchers to better manage the various ecosystems on the planet. This line of research has also stimulated the development of an undergraduate course called "Photosynthesis; From Basic Mechanisms to Biofuels", which is currently being taught at Stanford University, and has led to the training of postdoctoral fellows, undergraduate students and graduate students. Finally, this project has facilitated both national and international collaborations; with prominent laboratories.