Synthesis and characterization of macrocyclic peptide inhibitors of the Galpha protein family

干扰异源三聚体G蛋白活性的分子为更好地理解蛋白质结构及其作用机制提供了有价值的工具。此外，这些化合物也可能成为研究生理状态的合适物质，并可能因此提供对各自机制的见解。对特异性G蛋白抑制剂的明确需求尚未得到满足。因此，设计和合成具有较好理化和药理特性的大环肽抑制剂是本课题的主要目的。研究基于现有的环状沉积肽FR900359和结构相关的YM-254890。结构简化的分子将首先作为模板，用于逐步优化合成单个ym相关肽的反应条件。为此，固相肽合成的方案将基于构建模块的介绍和困难序列的手册来建立，以应对天然对应物的结构要求。多肽纯化和分析表征的方法将作为提供足够的材料进行结构阐明和生物学测试的先决条件。反过来，来自溶液核磁共振分析和不同生物测定的信息将用于进行深入的构效关系研究和特定G蛋白抑制剂的计算设计。在第二种方法中，寻找不同的Galpha蛋白抑制剂将通过筛选组合肽库来支持，该组合肽库将基于使用构建块的初始调查来构建。化合物的结合能力和抑制特性以及它们的结构-活性关系的评估将通过重组表达G蛋白的设想提供额外的支持。总之，这些研究可能为深入了解单个G蛋白的作用机制和研究涉及G蛋白的生理途径的潜在新物质提供重要工具。

Molecules that interfere with the activity of heterotrimeric G proteins represent valuable tools for a better understanding of the protein structure and its mechanism of action. Such compounds, in addition, may also turn out suitable substances for investigating physiological states and may thus provide insight into the respective mechanisms. The clear demand for specific G protein inhibitors has not been satisfied yet. Thus, it is the primary aim of this project to design and synthesize macrocyclic peptide inhibitors with improved physico-chemical and pharmacological properties. The investigations are based on the existing cyclic depsipeptide FR900359 and the structurally related YM-254890. Structurally simplified molecules will initially serve first as templates for a stepwise optimization of the reaction conditions for the synthesis of individual YM-related peptides. For this purpose, protocols for solid phase peptide synthesis will be established based on the introduction of building blocks and manuals for difficult sequences to cope with the structural demands of the natural counterpart. Methods for peptide purification and analytical characterization will serve as prerequisite to supply sufficient material for structure elucidation and biological testing. In turn, information from solution NMR analysis and different bioassays will be used to perform in-depth structure-activity relationship studies and computational design of specific G protein inhibitors. In a second approach, the search for such inhibitors of different Galpha proteins will be supported by screening a combinatorial peptide library, which will be constructed based on the initial investigations using building blocks. Evaluation of the compounds binding capacities and inhibitory properties as well as their structure-activity relationships will be additionally supported by the envisaged provision of recombinantly expressed G proteins. Altogether, these studies may provide important tools to offer a profound insight into the mechanism of action of individual G proteins and potential novel substances for studying physiological pathways involving G proteins.