Bacterial Reaction Centers with New Photochemical Properties

生命科学化学计划资助亚利桑那州立大学的詹姆斯·艾伦教授进行题为“具有新的光化学性质的细菌反应中心”的研究。在所有的光合作用系统中，主要的能量传递事件是光诱导色素-蛋白质复合体中电荷分离态的产生。尽管不同生物体的具体途径不同，但总体模式是非常保守的，对这些过程的理解是当前设计模拟光合作用过程的人工系统的基础。球形红细菌的反应中心可以作为一个模型系统来结合光系统II的特征，如高度氧化的初级供体。氧化还原活性单核锰辅因子的最新发展为研究新型锰辅因子和将新的光驱动反应引入这一光系统提供了机会。这项研究的第一个目标是设计新的锰协因子，并将这些协因子的性质与不同的实验观察值相关联。第二个目标是利用这个模型系统来探索光系统II的Mn4Ca簇的关键性质，即水被氧化的位置。总体而言，从这些研究中获得的分子洞察力应该会对开发金属酶的设计原则、理解光合作用中的电子传递机制以及改进能量转换技术产生普遍影响。我们的研究通过提供更广泛的参与本科生研究的机会，通过编写教科书来应对本科教育中的挑战，为新的跨学科研究生课程创建课程，促进与公众的科学交流，以及赞助面向有限科学研究机会的学生的外展努力，来促进科学进步。这个项目得到了分子和细胞生物科学部生物分子动力学、结构和功能集群的共同资助。

The Chemistry of Life Sciences Program funds Professor James Allen of Arizona State University for research entitled "Bacterial Reaction Centers with New Photochemical Properties." In all photosynthetic systems, the primary energy transduction event is the light-induced generation of a charge-separated state in a pigment-protein complex. Although the specific pathways vary among organisms, the general pattern is remarkably conserved, and an understanding of these processes serves as the basis for current designs of artificial systems that mimic the photosynthetic process. The reaction center from Rhodobacter sphaeroides can be used as a model system to incorporate features of photosystem II such as a highly oxidizing primary donor. The recent development of a redox active mononuclear Mn cofactor provides the opportunity to study novel manganese cofactors and to introduce new light-driven reactions into this photosystem. The first objective of the proposed research is to design novel Mn cofactors and correlate the properties of these cofactors with different experimental observables. The second objective is to use this model system to probe key properties of the Mn4Ca cluster of photosystem II that is the site of water oxidation. Overall, the molecular insight gained from these studies should have a general impact on developing design principles for metalloenzymes, understanding electron transfer mechanisms in photosynthesis, and improving energy conversion technologies. Our research promotes progress in science by providing wider opportunities for participation in undergraduate research, meeting challenges in undergraduate education by writing textbooks, creating a curriculum for a new interdisciplinary graduate program, fostering scientific communication to the general public, and sponsoring outreach efforts to students who have limited opportunities for scientific research. This project is receiving co-funding from the Biomolecular Dynamics, Structure and Function Cluster in the Division of Molecular and Cellular Biosciences.