Covalent and Transition State Inhibitor Design

该奖项资助纽约州立大学布法罗大学的安德鲁·穆尔金教授开发一系列化合物，这些化合物可能会作为植物和细菌新陈代谢的关键酶--异柠檬酸裂解酶(ICL)的特定抑制剂。抑制剂设计的障碍之一是确保与ICL的选择性结合超过其他潜在的靶点。实现这一目标通常需要抑制剂和酶之间的一种或一组特殊的相互作用。实现这一点的一种策略是引入一种抑制物的一部分，只有当靶子处于合适的相互作用位置时，它才会附着在靶子上。第二种策略是让抑制剂类似于催化转化过程中发生的事情。这会使酶与抑制剂紧密结合，并具有极高的特异性。目前的研究旨在开发通过这两种策略中的一种来抑制ICL的化合物，这可能被证明是一种抑制多种酶的通用手段。向本科生和研究生提供教育发展，当地教师将接受培训，向K-12学生介绍酶的实践课程。该项目利用脂肪族硝基化合物的两种性质，可能导致有效的酶抑制。其中第一个以前是未知的，因此进行了详细的调查。具体地说，当与酶结合时，与硝基相邻的碳在一定条件下可以作为电泳剂与邻近的半胱氨酸残基进行共价反应。提出了动力学、质谱学和X射线结晶学实验来阐明简单的硝基化合物与ICL之间发生该反应的机理。为了提高选择性，将制备更精细的硝基化合物并进行测试。将在这里使用的硝基化合物的第二个性质是它们的共轭碱，称为硝酸盐，与它们的羧酸等效物的ACI烯醇酸形式相似。通过利用动力学同位素效应和计算模拟，将确定ICL的过渡态。将准备过渡状态的硝酸盐类似物，目标是获得与ICL的强大约束力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award funds Professor Andrew Murkin of the University at Buffalo, The State University of New York, to develop a series of compounds that may serve as specific inhibitors of an enzyme critical to metabolism in plants and bacteria, known as isocitrate lyase (ICL). One of the obstacles to inhibitor design is ensuring selective binding to ICL over other potential targets. Meeting this goal usually requires a special interaction or group of interactions between the inhibitor and the enzyme. One strategy for accomplishing this is to introduce a part of an inhibitor that only sticks to the target if it is in just the right place for an interaction. A second strategy is to have the inhibitor resemble what is happening during the catalyzed conversion. This tricks the enzyme into binding to the inhibitor tightly and with great specificity. The current research aims to develop compounds that inhibit ICL by one of these two strategies, which may prove to be a general means for inhibiting numerous enzymes. Educational development is provided to undergraduate and graduate students, and local area teachers will be trained to perform hands-on lessons that introduce enzymes to K-12 students.This project exploits two properties of aliphatic nitro compounds that may lead to potent enzyme inhibition. The first of these is previously unknown and therefore investigated in detail. Specifically, the carbon adjacent to the nitro group can act as an electrophile for covalent reaction with a neighboring cysteine residue under certain conditions when bound to an enzyme. Kinetic, mass spectral, and X-ray crystallographic experiments are proposed to elucidate the mechanism by which this reaction occurs between a simple nitro compound and ICL. In an attempt to improve selectivity, more elaborate nitro compounds will be prepared and tested. The second property of nitro compounds that will be utilized here is the resemblance of their conjugate bases, called nitronates, to the aci enolate form of their carboxylic acid equivalents. Through the use of kinetic isotope effects and computational modeling, the transition state of ICL will be determined. Nitronate analogues of the transition state will be prepared, with the goal of obtaining strong binding with ICL.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.