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Targeting bacterial cell division with small molecules and peptides

用小分子和肽靶向细菌细胞分裂

基本信息

批准号：
10630926
负责人：
WILLIAM MARGOLIN
金额：
$ 19.5万
依托单位：
UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-06-01 至 2024-12-31
项目状态：
已结题

项目摘要

Resistance to antibacterial therapies continues to be an urgent threat to human health, particularly bacteria that are already resistant to multiple antibiotics. To discover and develop new antibacterials, it is important to find and exploit under-utilized antibiotic targets. One attractive candidate is the divisome, the dynamic protein complex that splits bacterial cells in two. The bacterial divisome contains a set of highly conserved and essential proteins that act coordinately to ensure the correct timing and placement of the cell division septum at mid-cell. The septal transpeptidase is already a target of several widely used beta-lactam antibiotics, but no other divisome protein is currently targeted. FtsZ, a highly conserved polymer-forming GTPase that forms a membrane-associated "Z ring" required for organizing the septal transpeptidase and other septum-synthesizing enzymes, is the only other divisome protein that has been studied extensively as a target of small molecules and peptides, and our lab has helped to advance the understanding of FtsZ and its interacting proteins for 30 years. Nevertheless, there is still much to learn about how small molecules perturb FtsZ function at the molecular and cellular level and whether these can lead to potential therapeutics. To address this over-arching theme, this proposal seeks to define, structurally and physiologically, two different sets of promising new small molecule inhibitors of FtsZ. The first is a set of two related benzamide derivatives, synthesized by our medicinal chemistry collaborators, that have high potencies against both Gram-positive bacteria and Gramnegative bacteria with disabled efflux pumps. These derivatives were synthesized to have optimized binding to the interdomain cleft (IDC) of FtsZ, a common target of inhibitors that we have termed FtsZ's "Achilles Heel". Unexpectedly, we found that these two compounds perturb FtsZ by distinct mechanisms in Gram-positive versus Gram-negative bacteria, prompting the hypothesis that they disrupt FtsZ's ability to assemble into the proper condensed polymer architecture needed for cell division to progress further. This model will be tested with our laboratory's unique interdisciplinary array of genetic, cytological, and structural biology methods. The second set of small molecule inhibitors is a pair of bacteriophage peptides that have evolved to target FtsZ as part of their lytic cycle. Each peptide binds directly to FtsZ and blocks Z ring assembly, but also binds to another essential divisome protein that tethers FtsZ to the cytoplasmic membrane. The molecular details of these binding sites are unknown, but we hypothesize that they do not involve the FtsZ IDC and instead perturb Z ring assembly by novel two-pronged mechanisms. Again, we will apply our extensive expertise in genetics, microscopy and structural biology of divisome proteins to elucidate these mechanisms. The insights we will gain from the proposed studies should lay a foundation for the future therapeutic potential of small molecules and peptides, potentially in combination with each other or with other antibiotics, to kill bacteria by disrupting the cell division machinery.

对抗菌疗法的耐药性仍然是对人类健康的紧迫威胁，特别是细菌已经对多种抗生素产生耐药性。为了发现和开发新的抗菌药物，重要的是发现并利用未充分利用的抗生素靶点。一个有吸引力的候选者是分裂体，动态蛋白质将细菌细胞一分为二的复合物。细菌分裂体包含一组高度保守且协调作用以确保细胞分裂隔膜的正确时间和位置的必需蛋白质中细胞。隔膜转肽酶已经是几种广泛使用的 β-内酰胺抗生素的靶标，但还没有其他分裂体蛋白目前是目标。 FtsZ，一种高度保守的聚合物形成 GTP 酶，可形成组织隔膜转肽酶和其他隔膜合成所需的膜相关“Z 环” 酶，是唯一一种作为小分子靶标被广泛研究的分裂蛋白和肽，我们的实验室帮助加深了对 FtsZ 及其相互作用蛋白的理解 30 年。尽管如此，关于小分子如何干扰 FtsZ 的功能，仍有很多东西需要了解。分子和细胞水平以及这些是否可以带来潜在的治疗方法。为了解决这个总体问题主题，该提案旨在从结构和生理上定义两组不同的有前途的新小型 FtsZ 分子抑制剂。第一个是一组两种相关的苯甲酰胺衍生物，由我们合成药物化学合作者，对革兰氏阳性菌和革兰氏阴性菌均具有高效能外排泵失效的细菌。这些衍生物的合成具有优化的结合 FtsZ 的域间裂口 (IDC) 是抑制剂的常见靶点，我们将其称为 FtsZ 的“致命弱点”。出乎意料的是，我们发现这两种化合物在革兰氏阳性菌中通过不同的机制扰乱 FtsZ 与革兰氏阴性细菌相比，引发了这样的假设：它们破坏了 FtsZ 组装成细胞分裂进一步进展所需的适当的缩合聚合物结构。该模型将被测试凭借我们实验室独特的跨学科遗传学、细胞学和结构生物学方法。这第二组小分子抑制剂是一对噬菌体肽，它们已进化为靶向 FtsZ 他们的裂解周期的一部分。每个肽直接结合 FtsZ 并阻断 Z 环组装，但也结合另一种重要的分裂体蛋白，将 FtsZ 固定在细胞质膜上。分子细节这些结合位点未知，但我们假设它们不涉及 FtsZ IDC，而是扰乱 Z 形环由新颖的双管机构组装。再次，我们将运用我们在遗传学方面广泛的专业知识，分裂蛋白的显微镜和结构生物学来阐明这些机制。我们将得到的见解拟议研究的成果将为小分子未来的治疗潜力奠定基础和肽，可能相互组合或与其他抗生素组合，通过破坏细菌来杀死细菌细胞分裂机器。