Molecular mechanisms of action of macrolide antibiotics

性状（由申请方提供）：大环内酯类抗生素通过干扰蛋白质合成抑制细胞生长。这些药物结合在新生的肽出口隧道，并根据广泛接受的观点，抑制所有细胞蛋白质的合成在翻译的早期回合相反，这种传统的大环内酯类作用模型，我们的初步研究表明，治疗革兰氏阳性和革兰氏阴性细菌与大环内酯类允许继续翻译的一个定义的蛋白质子集。此外，蛋白逃避抑制的能力由其N-末端序列决定，其可以绕过出口通道中的抗生素而不将药物从其结合位点置换。在最初的旁路之后，一些蛋白质的翻译可以继续直到它们完成，而一些多肽的合成可以在稍后阶段被阻止。这两种作用都取决于抗生素的结构。尽管功能 和医学意义的这些现象，分子机制的蛋白质的能力，以逃避抑制和药物诱导的翻译逮捕的要求是未知的，将在这个项目中解决。全细胞蛋白质组学将用于全面表征在抗生素存在下继续翻译的蛋白质。高度创新的核糖体分析技术将提供药物依赖性“晚期”翻译停滞位点的全基因组信息。全细胞研究将B，然后是在无细胞翻译系统中进行的旁路和阻滞分子机制的生物化学表征。最后，将分析结合在核糖体出口通道中的抗生素的结构与抗生素处理的细胞中合成的蛋白质的谱之间的相关性，并检查耐药基因组的组成的变化的生理后果。预期的研究结果应显着扩大临床重要的大环内酯类抗菌药物的一般作用模式的理解和开放的新场所开发具有上级抗生素性能的蛋白质合成抑制剂。

DESCRIPTION (provided by applicant): Macrolide antibiotics inhibit cell growth by interfering with protein synthesis. These drugs bind in the nascent peptide exit tunnel and, according to the widely accepted view, inhibit synthesis of all cellular proteins at the early rounds of translation In contrast to this conventional model of macrolide action, our preliminary studies showed that treatment of Gram-positive and Gram-negative bacteria with macrolides allows for continued translation of a defined subset of proteins. Further, the ability of the protein to evade inhibitio is determined by its N-terminal sequence which can bypass the antibiotic in the exit tunnel without displacing the drug from its binding site. After the initial bypass, translation of some proteins cn continue until their completion, whereas synthesis of some polypeptides can be arrested at later stages. Both of these effects depend on the structure of the antibiotic. In spite of the functional and medical significance of these phenomena, the molecular mechanisms underlying the ability of the protein to evade inhibition and the requirements for the drug-induced translation arrest are unknown and will be addressed in this project. Whole-cell proteomics will be used to comprehensively characterize proteins whose translation continues in the presence of the antibiotic. The highly-innovative technique of ribosome profiling will provide genome-wide information of the sites of drug-dependent 'late' translation arrest. The whole cell-studies will b followed by biochemical characterization of molecular mechanisms of bypass and arrest carried out in a cell-free translation system. Finally, the correlation between the structure of the antibiotic bound in the ribosomal exit tunnel and the spectrum of proteins synthesized in antibiotic-treated cells will be analyzed and physiological consequences of the variation in the composition of the resistome will be examined. The anticipated findings should significantly expand the understanding of the general mode of action of clinically-important macrolide antibacterials and open new venues for development of protein synthesis inhibitors with superior antibiotic properties.