At physiological temperatures functional motions arise from the interplay of different thermal motions of proteins and solvent. Here we determine the hierarchy in the protein conformational energy landscape that underlies these motions by using a series of temperature-dependent multinuclear solid-state NMR relaxation measurements in hydrated nanocrystalline GB1. We measure a set of thirteen different NMR relaxation rates in a single sample that are sensitive to dynamics occurring on different timescales and in different parts of the system over temperatures from 105 to 280 K. The analysis of multiple probes that report on the different structural components of this complex system allows us to develop a complete and coherent picture of the dynamic processes across the whole temperature range, as well as to rationalize prior observations from other techniques. The results support strong coupling between protein and solvent dynamics above 160 K, with fast solvent motions, slow protein side-chain motions, and fast protein backbone motions being activated consecutively. Low activation energy, small-amplitude local motions dominate at low temperatures, with larger-amplitude, anisotropic, and functionally relevant motions involving entire peptide units becoming dominant at temperatures above 220 K.<br/><br/>J. Lewandowski, M.E. Halse, M. Blackledge & L. Emsley, 'Direct observation of hierarchical protein dynamics,' <i>Science </i>348, 578-581 (2015).

Direct observation of hierarchical protein dynamics

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.