¹H-Detected Biomolecular NMR under Fast Magic-Angle Spinning

Abstract

Since the first pioneering studies on small deuterated peptides dating more than 20 years ago, 1H detection has evolved into the most efficient approach for investigation of biomolecular structure, dynamics, and interactions by solid-state NMR. The development of faster and faster magic-angle spinning (MAS) rates (up to 150 kHz today) at ultrahigh magnetic fields has triggered a real revolution in the field. This new spinning regime reduces the 1H–1H dipolar couplings, so that a direct detection of 1H signals, for long impossible without proton dilution, has become possible at high resolution. The switch from the traditional MAS NMR approaches with 13C and 15N detection to 1H boosts the signal by more than an order of magnitude, accelerating the site-specific analysis and opening the way to more complex immobilized biological systems of higher molecular weight and available in limited amounts. This paper reviews the concepts underlying this recent leap forward in sensitivity and resolution, presents a detailed description of the experimental aspects of acquisition of multidimensional correlation spectra with fast MAS, and summarizes the most successful strategies for the assignment of the resonances and for the elucidation of protein structure and conformational dynamics. It finally outlines the many examples where 1H-detected MAS NMR has contributed to the detailed characterization of a variety of crystalline and noncrystalline biomolecular targets involved in biological processes ranging from catalysis through drug binding, viral infectivity, amyloid fibril formation, to transport across lipid membranes.

The evolution of paramagnetic NMR as a tool in structural biology

“…(6) When discussing the use of high fields, it is mandatory to mention the use of solid-state NMR, where the absence/reduction of incoherent molecular tumbling yields an effective reduction of the Curie-spin relaxation 146,147 and, in parallel, the appearance of a “powder pattern” reflects the geometry and the anisotropy of the interaction of the nuclear spin with the “Curie Spin”, and encodes highly relevant structural/dynamical information. 11,127,148–150…”

“…145 (6) When discussing the use of high fields, it is mandatory to mention the use of solid-state NMR, where the absence/ reduction of incoherent molecular tumbling yields an effective reduction of the Curie-spin relaxation 146,147 and, in parallel, the appearance of a ''powder pattern'' reflects the geometry and the anisotropy of the interaction of the nuclear spin with the ''Curie Spin'', and encodes highly relevant structural/dynamical information. 11,127,[148][149][150] The possibility of providing structural information in solution with an increasing level of detail, in conjunction with the possibility of characterizing biomolecular dynamics, is expected to further increase the number of users and applications of paramagnetic NMR, and to foster the development of computational tools and automated protocols for integrated data analysis. These advancements will keep paramagnetic NMR vital in the foreseeable future, contributing to solve challenging and important biological problems.…”

Sensitivity-Enhanced Multidimensional Solid-State NMR Spectroscopy by Optimal-Control-Based Transverse Mixing Sequences

“…In structural biology, solid-state NMR has recently reached a similar level as solution-state NMR and has been used recently to determine the structure of insoluble proteins such as amyloids fibrils, , cytoskeleton associated factors, phage coat or tail spike proteins, , and membrane proteins. , This advance has been enabled by the recent progress in sample preparation including various isotope labeling strategies, development of fast magic-angle-spinning (MAS) hardware yielding more efficient averaging of anisotropic interactions, and the availability of ultrahigh magnetic fields resulting in increased resolution and sensitivity . In analogy to solution-state NMR, numerous proton-detected multidimensional solid-state NMR experimental schemes have been developed − to increase the effective resolution and to resolve the massive overlap of resonances in large protein systems. However, sensitivity remains the major obstacle for a broader applicability, in particular in the solid state, due to the integrated loss of sensitivity in the multiple magnetization transfer elements in high-dimensional pulse schemes.…”

Aromatic ring flips in differently packed ubiquitin protein crystals from MAS NMR and MD

“…The cubic-PEG-ub simulation cell contains 48 ubiquitin molecules equally divided between chain A (molecules 1-24) and chain B (molecules. The rod-PEG-ub simulation cell contains 24 ubiqutin molecules equally divided between chain A (molecules 1-8), chain B (molecules 9-16) and chain C (molecules[17][18][19][20][21][22][23][24]…”