细菌耐药导致抗生素纷纷失效，新抗菌模式成为指导抗耐药菌结构修饰的关键。红霉素的抗菌机制是阻碍新生蛋白从核糖体输出而抑菌，我们前期合成一种新型红霉素，作用细菌核糖体新生肽输出通道门靶点，不但抗耐药菌活性高还呈现杀菌剂特点。故此本申请提出假说：优化的杀菌活性与调控门靶点所致的选择性释放功能蛋白的新途径相关。本项目拟借助部分分子共价对接和核糖体与红霉素复合物的晶体数据虚拟设计，研究亲和核糖体门靶点在内的新型多靶点杀菌红霉素分子的合成策略，揭示门靶点协同其它靶点提高抗耐药菌活性的科学规律；然后利用多种生化手段研究杀菌机制的内在结构基础、差异蛋白质组学揭示调控门靶点对蛋白表达谱的影响，探索调控靶点与调控蛋白相结合的结构修饰新思路；最后优化杀菌红霉素结构的类药性质并提高代谢安全性，系统阐明杀菌红霉素的构效关系。临床抗生素半数以核糖体为靶标，本申请突破传统模式，可为未来提供一个调控蛋白网络的新抗菌模式。

The rising and increasingly prevalent bacterial resistance has led to the loss of the potency of the clinical antibiotics. Discovery of an effective antibacterial mode is crucial to structural modification of the skeleton against the resistance. Erythromycin is a protein synthesis inhibitor by blocking the release of nascent proteins. Recently we found if the bacteriostatic agent erythromycin was appropriately modified with a mode of interaction with the gate-function base A2062 located in the bacterial ribosomal nascent peptide exit tunnel (NPET), the resulting derivatives not only are against resistant pathogens but also become bactericidal agents. Thus we hypothesize the bactericidal activity results from a novel mechanism of modulating the gate-function base followed by selective release of some specific proteins. In this proposal, a new protocol of rational design based on the multi-base of the rRNA will be explored with the aid of the partial covalent molecular docking and the available complex crystal structures of RNA and erythromycins. By this way, we will unravel how to enhance the activity of new erythromycins against resistant bacteria by interacting with the rRNA multi-base including the gate-function base A2062. Furthermore, we will combine the advantage of modulating both the ribosomal bases and the protein networks, and synthesize more potent erythromycin derivatives. Then, X-ray diffraction crystallography plus chemfootprinting and differential proteomics techniques will be utilized to illuminate the effect of the obtained bactericidal erythromycins on the bacterial rRNA bases and the subsequent protein expression profiling, respectively. Finally, optimizing drug-like properties in combination with analysis of the structure-activity relationships will shed light on how to fight effectively against the erythromycin-resistant bacteria. This proposal is not limited by well-known mechanisms targeting at the bacterial ribosome, which account for a half of the clinical antibiotics. The research will pave a new avenue for future design of antibiotics facilitated by the protein networks-based bactericidal mechanism studied herein.