Verkhivker Gennady M
Keck Center for Science and Engineering, Schmid College of Science and Technology, Chapman University, 1 University Drive, Orange, California 92866, United States.
Depatment of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California 92618, United States.
J Phys Chem B. 2022 Jul 19. doi: 10.1021/acs.jpcb.2c03464.
Understanding the allosteric mechanisms of the Hsp90 chaperone interactions with cochaperones and client protein clientele is fundamental to dissect activation and regulation of many proteins. In this work, atomistic simulations are combined with perturbation-based approaches and dynamic network modeling for a comparative mutational profiling of the Hsp90 binding and allosteric interaction networks in the three Hsp90 maturation complexes with FKBP51 and P23 cochaperones and the glucocorticoid receptor (GR) client. The conformational dynamics signatures of the Hsp90 complexes and dynamics fluctuation analysis revealed how the intrinsic plasticity of the Hsp90 dimer can be modulated by cochaperones and client proteins to stabilize the closed dimer state required at the maturation stage of the ATPase cycle. In silico deep mutational scanning of the protein residues characterized the hot spots of protein stability and binding affinity in the Hsp90 complexes, showing that binding hot spots may often coincide with the regulatory centers that modulate dynamic allostery in the Hsp90 dimer. We introduce a perturbation-based network approach for mutational scanning of allosteric residue potentials and characterize allosteric switch clusters that control mechanism of cochaperone-dependent client recognition and remodeling by the Hsp90 chaperone. The results revealed a conserved network of allosteric switches in the Hsp90 complexes that allow cochaperones and GR protein to become integrated into the Hsp90 system by anchoring to the conformational switch points in the functional Hsp90 regions. This study suggests that the Hsp90 binding and allostery may operate under a regulatory mechanism in which activation or repression of the Hsp90 activity can be pre-encoded in the allosterically regulated Hsp90 dimer motions. By binding directly to the conformational switch centers on the Hsp90, cochaperones and interacting proteins can efficiently modulate the allosteric interactions and long-range communications required for client remodeling and activation.
了解热休克蛋白90（Hsp90）伴侣蛋白与共伴侣蛋白及客户蛋白之间的变构机制，对于剖析许多蛋白质的激活和调控至关重要。在这项工作中，将原子模拟与基于微扰的方法以及动态网络建模相结合，对三种含有FKBP51和P23共伴侣蛋白以及糖皮质激素受体（GR）客户蛋白的Hsp90成熟复合物中Hsp90的结合和变构相互作用网络进行了比较突变分析。Hsp90复合物的构象动力学特征和动力学波动分析揭示了Hsp90二聚体的内在可塑性如何被共伴侣蛋白和客户蛋白调节，以稳定ATP酶循环成熟阶段所需的闭合二聚体状态。对蛋白质残基进行的计算机深度突变扫描确定了Hsp90复合物中蛋白质稳定性和结合亲和力的热点，表明结合热点通常可能与调节Hsp90二聚体动态变构的调控中心重合。我们引入了一种基于微扰的网络方法来对变构残基电位进行突变扫描，并确定了控制Hsp90伴侣蛋白依赖共伴侣蛋白识别和重塑机制的变构开关簇。结果揭示了Hsp90复合物中一个保守的变构开关网络，该网络允许共伴侣蛋白和GR蛋白通过锚定在功能性Hsp90区域的构象开关点而整合到Hsp90系统中。这项研究表明，Hsp90的结合和变构可能在一种调控机制下运作，其中Hsp90活性的激活或抑制可以预先编码在变构调节的Hsp90二聚体运动中。通过直接结合到Hsp90上的构象开关中心，共伴侣蛋白和相互作用蛋白可以有效地调节客户蛋白重塑和激活所需的变构相互作用和远程通讯。
