Novel Imine Formation by ATP Grasp Enzymes

在化学学部生命过程化学研究项目的支持下，丁友松博士将与张学勇博士合作。来自佛罗里达大学的Steven Bruner和Gustavo Seabra，研究了一种被称为ATP抓住酶的酶超家族成员形成亚胺键（碳和氮通过两个键连接）的机制。亚胺对许多生命过程至关重要，它们是在许多类型的酶催化反应中形成的。然而，对于ATP抓住酶超家族中的酶如何催化亚胺的形成，人们知之甚少。ATP抓握超家族大约有55万个成员，其中一些成员催化核心生物途径的反应，例如，制造蛋白质、细胞壁和脂肪酸。利用一套生化、结构和计算工具，研究小组将描述两种ATP抓住酶如何促进亚胺的形成，以生产自然界中发现的复杂分子，并发现由亚胺形成ATP抓住酶驱动的新化合物和过程。该项目旨在提供关于大自然如何在同一酶家族中设计新功能的新见解，并揭示这些酶如何帮助制造用于生物技术的复杂分子。此外，这个项目将提供机会训练学生，特别是妇女和代表性不足的少数民族，掌握现代科学技术，从而为他们从事高级科学事业做好准备。通过与本科生研究中心、佛罗里达夏季本科生研究中心和佛罗里达大学预科教育和培训中心的合作，该项目还将吸引高中生和大学生参与研究，并通过对高中教师的外展活动扩大其更广泛的影响。亚胺是许多酶催化反应的关键中间体，也是新兴的具有生物活性的小分子官能团。已知ATP捕获酶可形成酰胺、酯或硫酯键。然而，两种ATP把握酶MysC和MysD催化亚胺形成，用于天然紫外线保护剂真菌孢素样氨基酸（MAAs）的生物合成，代表了该酶超家族的新化学性质。该项目将研究与atp依赖性抓握酶的典型反应机制的基本偏差的分子基础，这些反应机制有利于亚胺的形成。具体来说，研究团队将描述MysC（目标1）和MysD（目标2）的反应路径、底物要求、动力学细节和独特的结构特征，并探索ATP捕获酶的新化学特性所带来的新反应流形和过程（目标3）。因此，这项工作可能会增加我们对蛋白质序列变异对蛋白质结构和功能的影响的基本理解。此外，概述的研究可能会提供关于ATP把握酶超家族在自然界中的功能范围的新信息，揭示隐藏的化学多样性和生物过程，并开辟这些亚胺形成酶在生物技术中的长期应用。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemistry of Life Processes Program in the Division of Chemistry, Dr. Yousong Ding will collaborate with Drs. Steven Bruner and Gustavo Seabra, all from the University of Florida, to study the mechanism for the formation of an imine bond (carbon connected to nitrogen by two bonds) by members of an enzyme superfamily known as ATP grasp enzymes. Imines are essential to a number of life processes and they are formed during many types of enzyme-catalyzed reactions. However, little is known about how enzymes in the ATP grasp enzyme superfamily catalyze imine formation. The ATP grasp superfamily has about 550,000 members, some of which catalyze reactions for central biological pathways, e.g., making proteins, cell-walls, and fatty acids. Using a suite of biochemical, structural and computational tools, the research team will characterize how two ATP grasp enzymes promote the formation of imines for the production of complex molecules found in nature and discover new compounds and processes driven by imine-forming ATP grasp enzymes. This project aims to deliver novel insights into how nature has devised novel functions in the same enzyme family and reveal how these enzymes could aid in making complex molecules for applications in biotechnology. Furthermore, this project will provide opportunities for training students, particularly women and underrepresented minorities, in modern scientific techniques, thereby preparing them for advanced careers in science. Through established collaborations with the Center for Undergraduate Research, Summer Undergraduate Research at Florida, and the Center for Precollegiate Education and Training at the University of Florida, this project will also engage high school and college students in the research and magnify its broader impacts through outreach activities for high school teachers.The imine is important as a key reactive intermediate species in a number of enzyme catalyzed reactions and as an emerging functional group of bioactive small molecules. ATP grasp enzymes are known to form the amide, ester or thioester linkage. However, two ATP grasp enzymes MysC and MysD catalyze imine formation for the biosynthesis of natural UV protectants mycosporine-like amino acids (MAAs), representing new chemistry for this enzyme superfamily. This project will investigate the molecular basis for fundamental deviations from the canonical reaction mechanism for ATP-dependent grasp enzymes that favor imine formation here. Specifically, the research team will characterize the reaction paths, substrate requirements, kinetic details, and unique structural features of MysC (Objective 1) and MysD (Objective 2), and explore new reaction manifolds and processes enabled by the new chemistry of ATP grasp enzymes (Objective 3). As such, this work will likely add to our fundamental understanding of the consequences of protein sequence variation upon protein structure and function. Furthermore, the outlined studies will likely provide fresh information about the functional scope of the ATP grasp enzyme superfamily in nature, uncover hidden chemical diversity and biological processes, and open up longer term applications of these imine-forming enzymes in biotechnology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.