Chemical Synthesis to Translate Fusicoccanes into PPI Modulators

弗雷德里希实验室的研究重点是天然产物的化学和生物学 蛋白质-蛋白质相互作用(PPI)。我们的长期目标是了解和提高黄连的药理作用 我们的目标使用化学合成。在这个提案中，我们研究了一类复杂的二萜糖苷。 在人类细胞培养中证明了14-3-3个PPI的有效性。 14-3-3蛋白是一个调节数百个客户蛋白(CP)的适配分子家族，通过 形成二元蛋白质复合体。这个扩张型14-3-3相互作用体被整合到磷酸化- 依赖于调节细胞内稳态的信号通路。14-3-3/CP相互作用的失调 与癌症和神经系统疾病的发展有关。因此，靶向14-的小分子- 3-3功能是研究生化途径中14-3-3/CP相互作用的特殊工具。 它们还为开发新的治疗方式提供了领导结构的入口。 二萜糖苷褐变霉素A(Fc)和胚胎素A(CN)是典型的稳定的镰刀菌。 体内PPI为14-3-3。Fc参与一组精选的14-3-3/CP相互作用，并延长这些PPI的寿命 通过与这两种蛋白质形成接触。这种生物学为褐霉素-四氢呋喃的发展提供了种子，这是一种半 具有外围结构修饰的FC的合成类似物，改变了14-3-Fc的结合亲和力和选择性 3个PPI。这些观察向我们表明，FC和CN的共有碳环核是一种特权 Motif用于设计选择性14-3-3 PPI稳定剂。然而，进入这一子结构受到其 立体化学的复杂性，唯一现有的获取FC和CN的手段是通过生产真菌。 我们建议使用化学合成作为一种工具来利用这些化合物的潜在药理作用。 天然产品。目标1的目标是建立快速和模块化装配的综合蓝图 Fc和CN。在初步研究中，我们已经发展了光化学来灵活地制备碳环 我们的核心目标。在目标1中，我们将调整和扩展这一化学，以第一次完全完成 合成这些二萜糖苷的途径。目标2的目的是测试Fc核是否可以 具有卓越选择性的脚手架14-3-3 PPI稳定剂。为了支持这项工作，我们建立了 生物物理工具在存在或不存在人工合成的情况下分析14-3-3/CP功能相互作用 化合物。在计算模型的指导下，我们提出了针对三个目标的配体的定制合成 涉及癌症生物学的14-3-3个监管PPI。这项研究对人类疾病具有重要意义。 因为它将提供精细的分子工具来调节14-3-3功能，从而改变疾病的途径。这 这项工作对基础化学科学具有重要意义，因为它将建立一种通用的战略来准备 具有不同功能特性的熔丝手杖。这一建议是创新的，因为稳定蛋白质 在小分子PPI调控中，络合物是一种尚未被探索的策略。

Research in the Frederich Lab focuses on the chemistry and biology of natural products that modulate protein-protein interactions (PPIs). Our long-term objective is to understand and enhance the pharmacology of our targets using chemical synthesis. In this proposal, we investigate a family of complex diterpene glycosides with demonstrated efficacy for 14-3-3 PPIs in human cell culture. 14-3-3 proteins are a family of adapter molecules that regulate several hundred client proteins (CPs) by forming binary protein complexes. This expansive 14-3-3 interactome is integrated into the phosphorylation- depended signaling pathways that regulate cellular homeostasis. Dysregulation of 14-3-3/CP interactions has been implicated in the development of cancer and neurological disorders. Thus, small-molecules targeting 14- 3-3 functions harbor special potential as tools to interrogate 14-3-3/CP interactions in biochemical pathways. They also provide entry to lead structures for the development of new therapy modalities. The diterpene glycosides fusicoccin A (FC) and cotylenin A (CN) are archetypal fusicoccanes that stabilize 14-3-3 PPIs in vivo. FC engages a select set of 14-3-3/CP interactions and prolongs the lifetime of these PPIs by forming contacts with both proteins. This biology seeded the development of fusicoccin-THF, a semi- synthetic analog of FC with peripheral structural modifications that alter binding affinity and selectivity for 14-3- 3 PPIs. These observations suggest to us that the shared carbocyclic nucleus of FC and CN is a privileged motif for the design of selective 14-3-3 PPI stabilizers. However, entry to this substructure is hampered by its stereochemical complexity and the only existing means to access FC and CN is from producing fungi. We propose to use chemical synthesis as a tool to harness the potentially impactful pharmacology of these natural products. The objective of Aim 1 is to establish a synthetic blueprint for the rapid and modular assembly of FC and CN. In preliminary studies, we have developed photochemistry to flexibly prepare the carbocyclic core of our targets. In Aim 1, we will adapt and extend this chemistry to complete, for the first time, fully synthetic access to these diterpene glycosides. The objective of Aim 2 is to test whether the FC nucleus can scaffold 14-3-3 PPI stabilizers with superior selectivity profiles. In support of this work we have established biophysical tools to assay functional 14-3-3/CP interactions in the presence or absence of synthetic compounds. Guided by computational models, we propose custom syntheses of ligands targeting three regulatory 14-3-3 PPIs involved in cancer biology. The proposed research is significant to human disease because it will provide refined molecular tools to modulate 14-3-3 functions that modify disease pathways. This work is significant to fundamental chemical science because it will establish a versatile strategy to prepare fusicoccanes with diverse functional properties. This proposal is innovative because stabilizing protein complexes is an underexplored strategy in small-molecule PPI modulation.