Strategie zur Identifizierung zyklischer Peptide als selektive Inhibitoren von RNA-Protein-Wechselwirkungen zur antibakteriellen Therapie

结构化RNA元件在病毒、细菌和真核生物的基因调控中起着重要作用。细菌在mRNA中使用所谓的核糖开关将基因表达与代谢联系起来。配体与核糖开关的结合诱导构象变化，导致抑制相关基因的转录或翻译。环肽（cyclicpeptides，ZP）是一类高效、高亲和力的类药物，具有高度的稳定性、灵活性、可变性和广泛的生物活性。最近开发了产生遗传编码和表达的环肽文库的方法，当与体内筛选测定结合时，其允许直接鉴定活性成员。本文提出的项目的目的是建立一种体内筛选方法，以从表达文库中鉴定ZPs，其特异性结合细菌mRNA中的结构化和保守的RNA元件，以抑制病原菌的生长。这些ZP-RNA相互作用将进行生物化学，生物物理和结构表征，并从理论和生物药理学上分析其构象状态。基于这些结果，将引入影响ZPs动力学的化学修饰，导致与靶RNA的结合概率和亲和力增加。

Structured RNA-elements play an important role in the gene regulation of viruses, bacteria as well as eukrayotes. Bacteria use so called riboswitches in the mRNA to link gene expression to their metabolism. Binding of ligands to the riboswitch induces conformational changes resulting in the inhibition of transcription or translation of the respect gene. Cyclic peptides (ZP) belong to the most effective, high-affinity drug-like agents, which are extremely stable, flexible, variable and exhibit a wide range of biological activities. Recently methods were developed to generate libraries of genetically encoded and expressed cyclopeptides, which allow the direct identification of the active member when combined with an in vivo screening assay. Aim of the here proposed project is to establish an in vivo screening assay to identify ZPs from an expressed library, specifically binding to structured and conserved RNA elements in bacterial mRNAs in order to inhibit growth of pathogenic bacteria. These ZP-RNA interactions will be biochemical, biophysical and structural characterised and their conformational states theoretically and biophysically analysed. Based on these results, chemical modifications influencing the dynamics of the ZPs will be introduced, resulting in an increased binding probability and affinity to the target RNA.