Marion Dominique, Gauto Diego F, Ayala Isabel, Giandoreggio-Barranco Karine, Schanda Paul
Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 71 avenue des martyrs, 38000, Grenoble, France.
Chemphyschem. 2019 Jan 21;20(2):276-284. doi: 10.1002/cphc.201800935. Epub 2018 Dec 20.
Studying protein dynamics on microsecond-to-millisecond (μs-ms) time scales can provide important insight into protein function. In magic-angle-spinning (MAS) NMR, μs dynamics can be visualized by rotating-frame relaxation dispersion experiments in different regimes of radio-frequency field strengths: at low RF field strength, isotropic-chemical-shift fluctuation leads to "Bloch-McConnell-type" relaxation dispersion, while when the RF field approaches rotary resonance conditions bond angle fluctuations manifest as increased rate constants ("Near-Rotary-Resonance Relaxation Dispersion", NERRD). Here we explore the joint analysis of both regimes to gain comprehensive insight into motion in terms of geometric amplitudes, chemical-shift changes, populations and exchange kinetics. We use a numerical simulation procedure to illustrate these effects and the potential of extracting exchange parameters, and apply the methodology to the study of a previously described conformational exchange process in microcrystalline ubiquitin.
研究微秒至毫秒（μs-ms）时间尺度上的蛋白质动力学可以为蛋白质功能提供重要的见解。在魔角旋转（MAS）核磁共振中，可以通过在不同射频场强条件下的旋转框架弛豫色散实验来观察μs动力学：在低射频场强下，各向同性化学位移波动会导致“布洛赫-麦康奈尔型”弛豫色散，而当射频场接近旋转共振条件时，键角波动表现为速率常数增加（“近旋转共振弛豫色散”，NERRD）。在这里，我们探索对这两种情况进行联合分析，以便从几何幅度、化学位移变化、布居和交换动力学方面全面了解运动情况。我们使用数值模拟程序来说明这些效应以及提取交换参数的潜力，并将该方法应用于研究微晶泛素中先前描述的构象交换过程。
