Coherent Multidimensional Spectroscopy of the Oxygen Evolving Complex in Photosystem II

在化学系化学测量和成像项目的支持下，威斯康星大学赖特教授通过扩展其测量分子运动的能力，不断开发相干多维光谱（CMDS）。CMDC是一种分子指纹的光谱技术，可以帮助科学家区分复杂样品中存在的不同分子。在这个项目中，赖特教授使用一对激光脉冲来产生分子中不同电子的特定反应，然后在很宽的时间尺度范围内跟踪它们的能级变化。然后，他利用这项技术研究维生素B12是如何起作用的，以及绿色植物是如何在分子水平上利用阳光制造氧气的。研究这两个问题可以帮助我们更好地了解人体是如何工作的，以及如何更有效地利用太阳能。赖特教授还与一家仪器公司合作，通过降低成本，使其他科学家更容易使用，将CMDS技术商业化。通过这个项目，赖特教授为研究生、本科生和中学生提供了研究机会。他还热衷于使用主动学习方法为未来的STEM学生准备更好的国家竞争力，并与斯佩尔曼学院的暑期学生密切合作。赖特教授的项目有两个具体目标——了解维生素B12催化乙醇胺降解的酶促机制，以及光系统II中氧气进化复合体制造氧气的机制。维生素B12的机制可以作为理解酶促反应的模型。OEC机制是化学领域的重大挑战之一，特别是在开发太阳能方面。对于这两个系统，Wright教授使用CMDS创建了振动态和电子态的量子力学叠加，提供了定义具有量子态分辨率的机制所需的选择性和结构细节。具体来说，他正在努力(1)开发一种泵- cmds探针来创建3D光谱；(2)研究钴胺-乙醇胺解氨酶(EAL)-乙醇胺（EA）配合物中Co-C键的裂解，探讨乙醇胺转化为乙醛和氨的酶促反应；(3)表征光系统II中出氧配合物（OEC）的电子态和振动态，以了解水氧化机理。此外，赖特教授(1)继续在本科和研究生课程中发展主动学习方法；(2)通过REU项目与斯佩尔曼学院的学生合作；(3)计划通过网站教程、教育材料、出版物和会议传播CMDS。

With support from the Chemical Measurement and Imaging Program in the Division of Chemistry, Professor Wright at University of Wisconsin continuously develops coherent multidimensional spectroscopy (CMDS) by expanding its capability of measuring molecular motions. CMDC is a spectroscopic technique to fingerprint a molecule, which helps scientists to distinguish different molecules present in complex samples. In this project, Professor Wright uses a pair of laser pulses to create specific responses from different electrons in a molecule and then follow the change of their energy levels over a very wide range of time scales. He then uses this technique to study how vitamin B12 works and how green plants use sunlight to make oxygen at the molecular level. Studying these two questions could help us to better understand how human body works and how to harness solar energy more effectively. Professor Wright also works with an instrument company on the commercialization of the CMDS technique by reducing the cost and make it easier to use by other scientists. Through this project, Professor Wright provides research opportunities to graduate, undergraduate, and secondary school students. He is also passionate about using active learning methods to prepare future STEM students for better national competitiveness and works closely with summer students from Spelman College. Professor Wright's project has two specific goals - understanding the enzymatic mechanism for vitamin B12's catalysis of ethanolamine degradation and the mechanism by which the oxygen evolving complex in photosystem II makes oxygen. The vitamin B12 mechanism serves as a model for understanding enzymatic reactions. The OEC mechanism is one of the grand challenges of chemistry, particularly for developing solar energy. For both systems, Professor Wright uses CMDS to create quantum mechanical superpositions of vibrational and electronic states that provide the selectivity and structural details required to define the mechanisms with quantum state resolution. Specifically, he is working to (1) develop a pump-CMDS probe to create a 3D spectrum; (2) to study the Co-C bond cleavage in a cobalamin-ethanolamine ammonida lyase (EAL)-ethanolamine (EA) complex to investigate the enzymatic reaction converting ethanolamine to acetaldehyde and ammonia; and (3) to characterize the electronic and vibrational states of oxygen evolving complexes (OEC) in photosystem II to understand the water oxidation mechanism. In addition, Professor Wright (1) continues his development of active learning methods in undergraduate and graduate courses; (2) works with students from Spelman College through a REU program; and (3) plans to disseminate CMDS through web site tutorials, educational materials, publications and conferences.