A Novel Mechanism for Pyrimidine Methylation by a Flavin-dependent Enzyme

有了这个奖项，生命过程的化学计划正在支持密歇根大学的布鲁斯帕勒教授的研究，研究黄素依赖性胸苷酸合酶的反应机制。所有的生命都需要胸苷酸来合成DNA。经过半个世纪的详细研究，“经典”胸苷酸合成酶通过一系列共价中间体将碳从亚甲基四氢叶酸转移到脱氧尿苷一磷酸。它不需要假肢。相比之下，十年前才发现的依赖黄素的胸苷酸合成酶完成了同样的碳净转移，但不知何故黄素辅基对这个过程至关重要。将通过几种光谱和动力学方法来检查还原和氧化黄素辅基和从亚甲基四氢叶酸转移碳的反应，以期识别中间体并了解蛋白质如何控制反应。新的可能性将探讨黄素依赖性胸苷酸合成酶激活脱氧尿苷一磷酸的极化，而不是攻击的一个enzymic nucleophile.The更广泛的影响，这个项目包括洞察力的机制和进化的可塑性化学路线至关重要的生命。黄素依赖性胸苷酸合酶反应只是广泛存在的使核酸或其前体的嘧啶甲基化的反应的一个例子。对于参与的学生，该项目预计将提供多学科的培训，包括分子生物学，蛋白质生物化学，光谱学，动力学和有机合成。研究人员计划通过参与美国化学学会的SEED项目招募贫困高中生进入实验室。该项目由BIO董事会分子和细胞生物科学部的生物分子动力学，结构和功能集群共同资助。

With this award, the Chemistry of Life Processes program is supporting the research of Professor Bruce Palfey of the University of Michigan to study the reaction mechanism of the flavin dependent thymidylate synthase. All life requires thymidylate in order to synthesize DNA. The "classic" thymidylate synthase, studied in high detail for half a century, transfers carbon from methylenetetrahydrofolate to deoxyuridine monophosphate through a series of covalent intermediates. It does this without a prosthetic group. In contrast, flavin-dependent thymidylate synthase, discovered just a decade ago, accomplishes the same net transfer of carbon, but somehow the flavin prosthetic group is critical to the process. The reactions that reduce and oxidize the flavin prosthetic group and transfer carbon from methylenetetrahydrofolate will be examined by several spectroscopic and kinetic methods, in the hope of identifying intermediates and understanding how the protein controls the reactions. The novel possibility will be explored that flavin-dependent thymidylate synthase activates deoxyuridine monophosphate by polarization instead of attack by an enzymic nucleophile.The Broader Impacts of this project include insight on the mechanistic and evolutionary malleability of chemical routes critical to life. The flavin-dependent thymidylate synthase reaction is just one example of the widespread reactions that methylate the pyrimidines of nucleic acids or their precursors. For the students involved, this project is expected to provide multi-disciplinary training, including molecular biology, protein biochemistry, spectroscopy, kinetics and organic synthesis. The investigator plans to recruit underprivileged high school students into the laboratory via participation in the American Chemical Society's Project SEED.This project is being co-funded by the Biomolecular Dynamics, Structure and Function Cluster in the Molecular and Cellular Biosciences Division of the BIO Directorate.