Vulnerabilities in Metabolite, Heme-lron and Redox Environments

这个项目的重点是为结核分枝杆菌(Mtb)细胞壁定义新的机械范例。 生物合成和重塑，这是细胞生长和分裂所必需的。细胞壁生物合成是众所周知的关键抗结核药物的靶点，包括异烟肼、环丝氨酸和乙胺丁醇。我们将集中在细胞壁的肽聚糖(PG)层，它作为芽孢杆菌结构完整性的网络。最近的进展已经确定了参与PG动态平衡的蛋白质，要么是酶作用的(PG水解酶)，要么是参与调节作用的蛋白质(PnuB、FhaA和Liped II Flippase)。这些酶，以及其他细胞壁生物合成酶，代表着潜在的脆弱性，可以被用来设计新的结核病药物。 我们将采取多学科、多研究者的方法，利用我们的核心能力来解决有关结核分枝杆菌细胞壁生物发生及其调控的主要问题。在目标1中，我们将定义PG水解酶自我抑制的新的分子机制，以发现它们的毒性是如何减轻的。在目标2中，我们将对具有活性的PG水解酶的络合物进行结构表征。为了发现间接的细胞墙漏洞，我们 还将确定在不同环境中控制PG生物合成的调控因子复合体的结构。这些研究将首次揭示控制PG完整性的激活机制。 目的3重点确定PG水解酶和其他细胞壁靶标的小分子复合体的结构，以确定底物结合和抑制剂结合的基础。 通过测试有关细胞壁生物合成途径和调控网络的基本假设，该项目为开发有效的、选择性的结核分枝杆菌生长抑制剂奠定了基础。

This project is focused on defining new mechanistic paradigms for Mycobacterium tuberculosis (Mtb) cell wall. biosynthesis and remodeling, which are essential for cell growth and division. Cell-wall biosynthesis is the target of well-known, critical anti-tuberculars, including isoniazid, cycloserine and ethambutol. We will concentrate on the pepfidoglycan (PG) layer of the cell wall, which serves as a meshwork for the structural integrity of the bacillus. Recent progress has identified proteins involved in PG homeostasis either enzymatically (PG hydrolases) or in regulatory roles (PknB, FhaA, and the lipid II flippase). These, along with other cell-wall biosynthetic enzymes, represent potential vulnerabilities that could be exploited for design of new TB drugs. We will take a multidisciplinary, multi-investigator approach enabled by our Core capabilities to address major questions about Mtb cell-wall biogenesis and its regulation. In Aim 1, we will define new molecular mechanisms of auto-inhibition of PG hydrolases to discover how their toxicity is mitigated. In Aim 2, we will structurally characterize complexes of active PG hydrolases. To uncover indirect cell-wall vulnerabilities, we also will determine the structures of complexes of regulatory factors that control PG biosynthesis in diverse environments. These studies will uncover for the first time activation mechanisms that control PG integrity. Aim 3 focuses on determining structures of small-molecule complexes of PG hydrolases and other cell-wall targets to define the basis for subrate- and inhibitor-binding specificty. By testtng fundamental hypotheses about cell-wall biosynthettc pathways and regulatory networks, this project sets the stage to develop potent, selective inhibitors of Mtb growth.