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

结构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。细菌利用mRNA中的所谓核糖开关将基因表达与他们的新陈代谢联系起来。配体与核糖开关的结合会导致构象变化，从而抑制尊重基因的转录或翻译。环肽(ZP)是一类最有效、高亲和力的类药物，具有极高的稳定性、灵活性、多变性和广泛的生物活性。最近发展了一些方法来建立基因编码和表达的环肽文库，当与体内筛选试验相结合时，这些方法允许直接鉴定活性成员。本项目的目的是建立一种体内筛选方法，从表达的文库中鉴定ZPs，特异性地与细菌mRNAs中的结构和保守的RNA元件结合，以抑制病原菌的生长。这些ZP-RNA相互作用将是生化的、生物物理的和结构的特征，并从理论和生物物理上分析它们的构象状态。基于这些结果，将引入影响ZPs动力学的化学修饰，从而增加与目标RNA的结合概率和亲和力。

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.