Collaborative Research: De novo Protein Constructs for Photosynthetic Energy Transduction

通过这一奖项，生命过程化学项目资助了杜克大学的Michael J.Therien、宾夕法尼亚大学的Jeffery G.Saven和加州大学旧金山分校的William F.DeGrado进行研究，以进一步了解植物从阳光中获取能量的准确方式。蛋白质在生物体中发挥许多功能，并催化生命所必需的一系列复杂的化学反应。在这些功能中，最关键的是能量从一种形式转化为另一种形式，例如在光合作用期间，植物将阳光转化为化学能。作为这一过程的结果，每年都有数以吨计的二氧化碳从大气中被去除。在这项工作中，研究人员正在构建人造蛋白质，以模拟植物中参与光合作用的蛋白质的行为。这一策略为测试天然光合作用蛋白的工作原理提供了重要手段。然后，重要的见解可以被用来开发新的蛋白质，使自然界中没有的能量转换过程得以实现。这项工作将通过提高对光合作用涉及的关键分子事件的理解，对生物学和能量储存等不同领域产生更广泛的影响。这对培养下一代科学家产生了更广泛的影响。这种独特的多机构结构为所有教育水平的学生提供了额外的机会，让他们参与在三个不同州进行的令人兴奋的合作研究。在这项研究中，为光合作用能量传递和储存提供的关键蛋白质设计原则正在被阐明。为了实现这一目标，人们采用了一种综合的、多学科的方法，重点是多肽-辅因子复合体的进化，这些复合体经历了光诱导的电荷转移反应，其中蛋白质基质稳定了电荷分离状态，并引导电子和空穴的有效分离。为此：(I)正在设计和合成捕光和氧化还原活性辅因子；(Ii)从头蛋白也被设计成选择性地结合这些单位的连接组件；(Iii)这些从头蛋白然后被表达和鉴定；(Iv)正在使用最先进的泵浦-探测瞬变光学方法来研究经历光诱导电子转移的从头蛋白；(V)实验数据正在指导辅因子和蛋白质的设计和重新设计，最初侧重于将适当的氨基酸侧链定位在供体和受体氧化还原位点附近，以调节电荷分离和电荷重组动力学；以及(Vi)通过自组装控制取向的重新设计的组件的光谱和动力学性质被表征为其纳米结构电子环境的函数。来自这项研究的信息为蛋白质结构和动力学方面提供了新的见解，这些方面对于高效的光子能量转换是不可或缺的，推动了功能从头设计的极限，并指导了具有独特光合作用功能的复杂多肽-辅因子组件的设计。该项目由分子和细胞生物科学部门的分子生物物理学集群和计算和数据启用的科学与工程计划共同资助

With this award, the Chemistry of Life Processes Program is funding Michael J. Therien (Duke University), Jeffery G. Saven (University of Pennsylvania), and William F. DeGrado (University of California at San Francisco) for research to further the understanding of the precise way plants capture energy from sunlight. Proteins perform many functions in living organisms and catalyze the complex set of chemical reactions necessary for life. Among the most critical of these functions is the conversion of energy from one form to another, such as during photosynthesis, when plants convert sunlight to chemical energy. As a result of this process, tons of carbon dioxide are removed from the atmosphere every year. In this work, the investigators are building artificial proteins that mimic the behavior of proteins in plants involved in photosynthesis. This strategy provides an important means to test how natural photosynthetic proteins work. Important insights can then be used to develop novel proteins that enable energy conversion processes not found in nature. The work will have a broader impact on diverse fields such as biology and energy storage, through the heightened understanding of key molecular events involved in photosynthesis. There is further broad impact on the training of the next generation of scientists. The unique multi-institution structure provides additional opportunities for students of all educational levels, graduate and undergraduate as well as high school, to participate in an exciting collaborative investigation being carried out in three different states.In this research, key protein design principles that provide for photosynthetic energy transduction and storage are being elucidated. An integrated, multi-disciplinary approach is employed toward this goal, and focus is on the evolution of peptide-cofactor complexes that undergo photoinduced charge-transfer reactions, where the protein matrix stabilizes the charge-separated state and guides the efficient separation of electrons and holes. Toward this end: (i) light-harvesting and redox-active cofactors are being designed and synthesized; (ii) de novo proteins are also being designed to selectively bind linked assemblies of these units; (iii) these de novo proteins are then expressed and characterized; (iv) de novo photosynthetic proteins that undergo photo-induced electron transfer are being interrogated using state-of-the-art pump-probe transient optical methods; (v) experimental data is guiding cofactor and protein design and redesign, initially focusing on the positioning of appropriate amino acid side chains near donor and acceptor redox sites to modulate charge separation and charge recombination dynamics; and (vi) the spectroscopic and dynamical properties of re-designed assemblies that control orientation via self-assembly are being characterized as functions of their nanostructured electronic environments. Information from this study is providing new insights into aspects of protein structure and dynamics that are integral for highly efficient photonic energy conversion, pushing the limits of functional de novo design, and guiding the design of complex peptide-cofactor assemblies that have unique photosynthetic functionality.This project is co-funded by the Molecular Biophysics Cluster in the Division of Molecular and Cellular Biosciences and the Computational and Data-Enabled Science and Engineering program