Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems (ICMS) , Eindhoven University of Technology , 5600 MB Eindhoven , The Netherlands.
Department of Pharmaceutical Chemistry and Small Molecule Discovery Centre (SMDC) , University of California , San Francisco 94143 , United States.
J Am Chem Soc. 2019 Feb 27;141(8):3524-3531. doi: 10.1021/jacs.8b11658. Epub 2019 Feb 19.
Modulation of protein-protein interactions (PPIs) by small molecules has emerged as a valuable approach in drug discovery. Compared to direct inhibition, PPI stabilization is vastly underexplored but has strong advantages, including the ability to gain selectivity by targeting an interface formed only upon association of proteins. Here, we present the application of a site-directed screening technique based on disulfide trapping (tethering) to select for fragments that enhance the affinity between protein partners. We target the phosphorylation-dependent interaction between the hub protein 14-3-3σ and a peptide derived from Estrogen Receptor α (ERα), an important breast cancer target that is negatively regulated by 14-3-3σ. We identify orthosteric stabilizers that increase 14-3-3/ERα affinity up to 40-fold and propose the mechanism of stabilization based on X-ray crystal structures. These fragments already display partial selectivity toward ERα-like motifs over other representative 14-3-3 clients. This first of its kind study illustrates the potential of the tethering approach to overcome the hurdles in systematic PPI stabilizer discovery.
小分子对蛋白质-蛋白质相互作用（PPIs）的调节已成为药物发现的一种有价值的方法。与直接抑制相比，PPI 稳定化的研究还远远不够，但它具有很强的优势，包括通过靶向仅在蛋白质结合时形成的界面来获得选择性的能力。在这里，我们介绍了一种基于二硫键捕获（系链）的定点筛选技术在选择增强蛋白质伴侣之间亲和力的片段方面的应用。我们的目标是磷酸化依赖性相互作用的hub 蛋白 14-3-3σ 和来自雌激素受体α（ERα）的肽之间的相互作用，ERα 是一个重要的乳腺癌靶点，它受 14-3-3σ 的负调控。我们确定了正构稳定剂，可将 14-3-3/ERα 的亲和力提高多达 40 倍，并基于 X 射线晶体结构提出了稳定化的机制。这些片段已经显示出对 ERα 样基序的部分选择性，而对其他代表性的 14-3-3 客户则没有选择性。这项首例研究说明了系链方法在克服系统的 PPI 稳定剂发现障碍方面的潜力。
