Laboratory of Chemical Biology, Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology , Den Dolech 2, 5612 AZ Eindhoven, The Netherlands.
Department of Chemistry, University of Duisburg-Essen , Universitätsstrasse 7, 45117 Essen, Germany.
J Am Chem Soc. 2017 Nov 15;139(45):16256-16263. doi: 10.1021/jacs.7b07939. Epub 2017 Nov 2.
Protein regions that are involved in protein-protein interactions (PPIs) very often display a high degree of intrinsic disorder, which is reduced during the recognition process. A prime example is binding of the rigid 14-3-3 adapter proteins to their numerous partner proteins, whose recognition motifs undergo an extensive disorder-to-order transition. In this context, it is highly desirable to control this entropy-costly process using tailored stabilizing agents. This study reveals how the molecular tweezer CLR01 tunes the 14-3-3/Cdc25CpS216 protein-protein interaction. Protein crystallography, biophysical affinity determination and biomolecular simulations unanimously deliver a remarkable finding: a supramolecular "Janus" ligand can bind simultaneously to a flexible peptidic PPI recognition motif and to a well-structured adapter protein. This binding fills a gap in the protein-protein interface, "freezes" one of the conformational states of the intrinsically disordered Cdc25C protein partner and enhances the apparent affinity of the interaction. This is the first structural and functional proof of a supramolecular ligand targeting a PPI interface and stabilizing the binding of an intrinsically disordered recognition motif to a rigid partner protein.
参与蛋白质-蛋白质相互作用（PPIs）的蛋白质区域通常表现出高度的固有无序性，这种无序性在识别过程中会降低。一个典型的例子是刚性 14-3-3 衔接蛋白与其众多伴侣蛋白的结合，其识别模体经历广泛的无序到有序的转变。在这种情况下，使用定制的稳定化剂来控制这种熵成本高的过程是非常可取的。本研究揭示了分子夹 CLR01 如何调节 14-3-3/Cdc25CpS216 蛋白质-蛋白质相互作用。蛋白质晶体学、生物物理亲和力测定和生物分子模拟一致提供了一个显著的发现：超分子“两面神”配体可以同时结合柔性肽 PPI 识别模体和结构良好的衔接蛋白。这种结合填补了蛋白质-蛋白质界面中的一个空白，“冻结”了固有无序的 Cdc25C 蛋白伴侣的构象状态之一，并增强了相互作用的表观亲和力。这是第一个针对 PPI 界面的超分子配体的结构和功能证明，并稳定了固有无序识别模体与刚性伴侣蛋白的结合。
