Coherent Multidimensional Spectroscopy of the Oxygen Evolving Complex in Photosystem II

化学系的化学测量和成像以及化学结构、动力学和机制项目资助了约翰·C·史密斯教授。赖特的威斯康星州大学开发激光光谱学方法测量复杂的分子系统与量子状态的分辨率。这些方法类似于大脑从三种类型的视网膜锥细胞的反应中区分颜色的能力。激光方法使用三种不同的激光束颜色来同时激发特定分子的三种量子态，从而驱动光合作用。这些方法为发现植物如何通过解析光合作用中实际涉及的量子态来制造氧气提供了关键。主要研究目标是应用新的激光方法来理解光合作用中的放氧机制。氧是在光系统II（PS II）的氧释放中心（OEC）产生的。OEC含有Mn、O和Ca离子以及氨基酸配体。激光束的颜色将激发OEC的振动和电子状态的不同组合，使其与PS II中数量大得多的分子区分开来。不同的过渡金属配位络合物钴胺素将作为测试和开发方法的模型系统。该项目将解决量子状态的变化，因为OEC的进展，通过其不同的氧化态。这些变化将与X射线激光生物学NSF-STC计划测量的变化相关联。这项研究的影响扩大了代表性不足的少数民族的参与;战略，材料和教育基础设施的发展，需要在大学课堂上实施积极的学习;并通过不同的沟通渠道传播的研究。最广泛的影响是为如何有效地收集和利用太阳能为我们的能源未来提供了一个模型。

The Chemical Measurement and Imaging and the Chemical Structure, Dynamics and Mechanisms Programs of the Chemistry Division have funded Professor John C. Wright of the University of Wisconsin to develop laser spectroscopy methods for measuring complex molecular systems with quantum state resolution. The methods are analogous to the brain's ability to distinguish colors from the response of the three types of retinal cone cells. The laser methods use three different laser beam colors to simultaneously excite three quantum states of specific molecules that proceed to drive photosynthesis. The methods provide the key for discovering how plants make oxygen by resolving the quantum states actually involved in photosynthesis. The primary research goal is applying the new laser methods to understanding the mechanism of oxygen evolution in photosynthesis. Oxygen is created at the oxygen evolution center (OEC) in photosystem II (PS II). The OEC contains Mn, O, and Ca ions and amino acid ligands. The laser beam colors will excite different combinations of vibrational and electronic states of the OEC that distinguish it from the much larger number of molecules in PS II. Different transition metal coordination complexes cobalamin will serve as model systems for testing and developing the methods. The project will resolve the quantum state changes as the OEC progresses through its different oxidation states. The changes will be correlated with those measured by the Biology with X-ray lasers NSF-STC program. The impact of this research is broadened by the participation of under-represented minorities; the development of strategies, materials, and the educational infrastructure required to implement active learning in college classrooms; and the dissemination of the research through different communication channels. The broadest impact is providing a model for how to efficiently collect and use solar energy for our energy future.