RNA modification and antibiotic resistance

摘要 抗生素在细菌感染治疗中的应用彻底改变了现代医疗实践。在……里面 自那以后的几十年里，不适当的使用控制和细菌惊人的能力相结合 对这些药物产生抗药性的人群严重限制了许多药物的临床应用 抗生素。我们现在正处在一个关键时刻，大多数有用的抗生素都知道，有时 广泛的抗药性，几乎没有新的替代方案或战略来解决耐药性问题 发展。许多临床上有用的抗生素都是针对细菌核糖体的。一种日益流行的形式 对这些药物的耐药性是指通过获得或改变核糖体RNA(RRNA)的修饰状态 内源性甲基转移酶。而负责整合这些抗生素耐药性的酶- 相关的rRNA修饰是已知的，但我们对其作用机制(如 特定底物识别)，这可能提供可行的新靶点来对抗耐药性。此外，我们还 目前对rRNA甲基化如何影响核糖体抗生素的分子基础知之甚少 互动。本应用程序中建议的实验将直接解决我们的 RRNA甲基化和细菌抗生素耐药性的基础知识。在前两个目标中，我们将 确定两种不同的rRNA修饰酶识别核糖体亚基的分子机制， 获得性氨基糖苷类耐药16S rRNA(M7G1405)甲基转移酶(AIM 1)及其内源性 结核分枝杆菌甲基转移酶TlyA(目标2)。接下来，我们将开发一种新的计算和 理解抗生素-甲基化rRNA相互作用的实验框架(目标3)。我们的目标是解释 在分子水平上，rRNA修饰如何限制药物疗效，以及如何避免这些影响。 总的来说，这三个独立但相辅相成的目标的结果将深化我们的根本 了解rRNA修饰酶使用的分子策略和rRNA的影响 甲基化对细菌抗生素耐药性的影响。我们的结果将支持未来的创新战略，以应对 由这些酶产生的抗药性，例如，通过促进m7G1405抑制剂的发展 甲基转移酶活性或30S底物结合，也可能导致新的合理设计 能够完全避开rRNA修饰效果的抗菌剂。

ABSTRACT The application of antibiotics to the treatment of bacterial infections revolutionized modern medical practice. In the decades since, a combination of improperly controlled usage and the remarkable ability of bacterial populations to develop resistance to these drugs has severely restricted the clinical usefulness of many antibiotics. We are now at a critical juncture where the majority of useful antibiotics have known and sometimes extensive resistance, and few novel replacements or strategies to combat the resistance problem are in active development. Many clinically useful antibiotics target the bacterial ribosome. One increasingly prevalent form of resistance to these drugs is alteration of the modification status of the ribosomal RNA (rRNA) via acquired or intrinsic methyltransferase enzymes. While enzymes responsible for incorporating these antibiotic resistance- associated rRNA modifications are known, we understand far less about their mechanisms of action (such as specific substrate recognition), which might offer viable new targets to counter the resistance. Further, we also currently have a poor understanding of the molecular basis for how rRNA methylation affects ribosome-antibiotic interactions. The experiments proposed in this application will directly address these critical gaps in our fundamental knowledge of rRNA methylation and bacterial antibiotic resistance. In the first two aims we will define the molecular mechanisms of ribosome subunit recognition by two different rRNA modification enzymes, the acquired aminoglycoside-resistance 16S rRNA (m7G1405) methyltransferases (Aim 1) and the intrinsic Mycobacterium tuberculosis methyltransferase TlyA (Aim 2). Next, we will develop a new computational and experimental framework for understanding antibiotic-methylated rRNA interactions (Aim 3). Our goal is to explain at the molecular level how rRNA modifications limit drug efficacy and how these effects can be evaded. Collectively, the results of these three independent but complementary aims will deepen our fundamental understanding of the molecular strategies used by rRNA modification enzymes and the impacts of rRNA methylation on antibiotic resistance in bacteria. Our results will support future innovative strategies to counter the resistance conferred by these enzymes, for example, by facilitating the development of inhibitors of m7G1405 methyltransferase activity or 30S substrate binding, and could also lead to the rational design of novel antimicrobials capable of fully evading the effects of rRNA modification.