Chapter 4 - Nuclear magnetic resonance spectroscopy for protein structure, folding, and dynamics

Abstract

Understanding protein folding is one of the fundamental requirements for understanding life. From the early breakthrough of Christian Anfinsen or the concept of Levinthal's paradox to the current times, thousands of initiatives have contributed to understanding protein folding. The folding of a protein can be defined as a dynamic, fundamental, but complex process, which could be attained through an optimization process proceeded through one or more partially folded nonnative states and/or disordered states with different levels of associations. Three states are typically defined according to their energy barrier in the protein folding landscape. They are classified as native, low populous nonnative or unfolded states, and sparsely populous intermediate states. Generally, the native state is the critical requirement for structural biology due to its functional implications. However, recent studies have shown that the nonnative states also play a crucial role in ligand-binding and aggregation-related diseases. The development of modern nuclear magnetic resonance (NMR) spectroscopy approaches has helped perform detailed investigations of protein folding and associated dynamics. Since protein folding is a time-dependent process, and many different protein assemblies fold in different timescale ranges, the dynamic study is critical to understanding minute alterations in the folding process. Here, we reviewed different NMR-based approaches to study protein folding dynamics that are differentiated based on their functional inputs, timescale resolution, and atomic-level insights of protein folding. Together, these discussions highlight the immense potential of modern NMR spectroscopy toward unraveling the in-depth molecular mechanism of protein folding, thereby opening a new era in biomedical science.