Department of Biochemistry and Molecular Genetics, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, Colorado 80045, United States.
Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, ETH-Hönggerberg, Zürich CH-8093, Switzerland.
J Am Chem Soc. 2021 Oct 6;143(39):16055-16067. doi: 10.1021/jacs.1c06289. Epub 2021 Sep 27.
Proteins composed of multiple domains allow for structural heterogeneity and interdomain dynamics that may be vital for function. Intradomain structures and dynamics can influence interdomain conformations and . However, no established structure determination method is currently available that can probe the coupling of these motions. The protein Pin1 contains separate regulatory and catalytic domains that sample "extended" and "compact" states, and ligand binding changes this equilibrium. Ligand binding and interdomain distance have been shown to impact the activity of Pin1, suggesting interdomain allostery. In order to characterize the conformational equilibrium of Pin1, we describe a novel method to model the coupling between intra- and interdomain dynamics at atomic resolution using multistate ensembles. The method uses time-averaged nuclear magnetic resonance (NMR) restraints and double electron-electron resonance (DEER) data that resolve distance distributions. While the intradomain calculation is primarily driven by exact nuclear Overhauser enhancements (eNOEs), couplings, and residual dipolar couplings (RDCs), the relative domain distribution is driven by paramagnetic relaxation enhancement (PREs), RDCs, interdomain NOEs, and DEER. Our data support a 70:30 population of the compact and extended states in apo Pin1. A multistate ensemble describes these conformations simultaneously, with distinct conformational differences located in the interdomain interface stabilizing the compact or extended states. We also describe correlated conformations between the catalytic site and interdomain interface that may explain allostery driven by interdomain contact.
由多个结构域组成的蛋白质允许结构异质性和结构域间动力学，这可能对功能至关重要。结构域内结构和动力学可以影响结构域间构象和。然而，目前还没有可用于探测这些运动耦合的既定结构确定方法。Pin1 蛋白包含单独的调节和催化结构域，这些结构域可以分别采用“扩展”和“紧凑”状态，配体结合会改变这种平衡。配体结合和结构域间距离已被证明会影响 Pin1 的活性，这表明结构域间变构作用。为了描述 Pin1 的构象平衡，我们描述了一种新的方法，该方法使用多态集合以原子分辨率模拟结构域内和结构域间动力学的耦合。该方法使用时间平均核磁共振（NMR）约束和双电子电子共振（DEER）数据来解析距离分布。虽然结构域内计算主要由精确核 Overhauser 增强（eNOE）、 耦合和残余偶极耦合（RDC）驱动，但相对结构域分布由顺磁弛豫增强（PRE）、RDC、结构域间 NOE 和 DEER 驱动。我们的数据支持apo Pin1 中存在 70:30 的紧凑和扩展状态群体。多态集合同时描述这些构象，结构域间界面上的独特构象差异稳定了紧凑或扩展状态。我们还描述了催化位点和结构域间界面之间的相关构象，这可能解释了由结构域间接触驱动的变构作用。
