TY - JOUR AB - Proton detection in solid state NMR is continuously developing and allows one to gain new insights in structural biology. Overall, this progress is a result of the synergy between hardware development, new NMR methodology and new isotope labeling strategies, to name a few factors. Even though current developments are rapid, it is worthwhile to summarize what can currently be achieved employing proton detection in biological solids. We illustrate this by analysing the signal-to-noise ratio (SNR) for spectra obtained for a microcrystalline α-spectrin SH3 domain protein sample by (i) employing different degrees of chemical dilution to replace protons by incorporating deuterons in different sites, by (ii) variation of the magic angle spinning (MAS) frequencies between 20 and 110 kHz, and by (iii) variation of the static magnetic field B0. The experimental SNR values are validated with numerical simulations employing up to 9 proton spins. Although in reality a protein would contain far more than 9 protons, in a deuterated environment this is a sufficient number to achieve satisfactory simulations consistent with the experimental data. The key results of this analysis are (i) with current hardware, deuteration is still necessary to record spectra of optimum quality; (ii) 13CH3 isotopomers for methyl groups yield the best SNR when MAS frequencies above 100 kHz are available; and (iii) sensitivity increases with a factor beyond B0 3/2 with the static magnetic field due to a transition of proton-proton dipolar interactions from a strong to a weak coupling limit. AU - Xue, K.* AU - Sarkar, R. AU - Tosner, Z.* AU - Reif, B. C1 - 65692 C2 - 52408 SP - 45-59 TI - Field and magic angle spinning frequency dependence of proton resonances in rotating solids. JO - Prog. Nucl. Magn. Reson. Spectrosc. VL - 130-131 PY - 2022 SN - 0079-6565 ER - TY - JOUR AB - Membrane proteins are important players in signal transduction and the exchange of metabolites within or between cells. Thus, this protein class is the target of around 60 % of currently marketed drugs, emphasizing their essential biological role. Besides functional assays, structural and dynamical investigations on this protein class are crucial to fully understanding their functionality. Even though X-ray crystallography and electron microscopy are the main methods to determine structures of membrane proteins and their complexes, NMR spectroscopy can contribute essential information on systems that (a) do not crystallize and (b) are too small for EM. Furthermore, NMR is a versatile tool for monitoring functional dynamics of biomolecules at various time scales. A crucial aspect of such studies is the use of a membrane mimetic that resembles a native environment and thus enables the extraction of functional insights. In recent decades, the membrane protein NMR community has moved from rather harsh detergents to membrane systems having more native-like properties. In particular, most recently phospholipid nanodiscs have been developed and optimized mainly for solution-state NMR but are now also being used for solid-state NMR spectroscopy. Nanodiscs consist of a patch of a planar lipid bilayer that is encircled by different (bio-) polymers to form particles of defined and tunable size. In this review, we provide an overview of available membrane mimetics, including nanodiscs, amphipols and bicelles, that are suitable for high-resolution NMR spectroscopy and describe how these advanced membrane mimetics can facilitate NMR studies on the structure and dynamics of membrane proteins. Since the stability of membrane proteins depends critically on the chosen membrane mimetic, we emphasize the importance of a suitable system that is not necessarily developed for solution-state NMR applications and hence requires optimization for each membrane protein. However, lipid-based membrane mimetics offer the possibility of performing NMR experiments at elevated temperatures and studying ligand and partner protein complexes as well as their functional dynamics in a realistic membrane environment. In order to be able to make an informed decision during the selection of a suitable membrane system, we provide a detailed overview of the available options for various membrane protein classes and thereby facilitate this often-difficult selection process for a broad range of desired NMR applications. (C) 2019 Elsevier B.V. All rights reserved. AU - Klöpfer, K. AU - Hagn, F. C1 - 56896 C2 - 47420 CY - The Boulevard, Langford Lane, Kidlington, Oxford Ox5 1gb, England SP - 271-283 TI - Beyond detergent micelles: The advantages and applications of non-micellar and lipid-based membrane mimetics for solution-state NMR. JO - Prog. Nucl. Magn. Reson. Spectrosc. VL - 114-115 PB - Pergamon-elsevier Science Ltd PY - 2019 SN - 0079-6565 ER - TY - JOUR AB - NMR spectroscopy is a key method for studying the structure and dynamics of (large) multidomain proteins and complexes in solution. It plays a unique role in integrated structural biology approaches as especially information about conformational dynamics can be readily obtained at residue resolution. Here, we review NMR techniques for such studies focusing on state-of-the-art tools and practical aspects. An efficient approach for determining the quaternary structure of multidomain complexes starts from the structures of individual domains or subunits. The arrangement of the domains/subunits within the complex is then defined based on NMR measurements that provide information about the domain interfaces combined with (long-range) distance and orientational restraints. Aspects discussed include sample preparation, specific isotope labeling and spin labeling; determination of binding interfaces and domain/subunit arrangements from chemical shift perturbations (CSP), nuclear Overhauser effects (NOEs), isotope editing/filtering, cross-saturation, and differential line broadening; and based on paramagnetic relaxation enhancements (PRE) using covalent and soluble spin labels. Finally, the utility of complementary methods such as small-angle X-ray or neutron scattering (SAXS, SANS), electron paramagnetic resonance (EPR) or fluorescence spectroscopy techniques is discussed. The applications of NMR techniques are illustrated with studies of challenging (high molecular weight) protein complexes. AU - Göbl, C.* AU - Madl, T. AU - Simon, B.* AU - Sattler, M. C1 - 31608 C2 - 34631 CY - Oxford SP - 26-63 TI - NMR approaches for structural analysis of multidomain proteins and complexes in solution. JO - Prog. Nucl. Magn. Reson. Spectrosc. VL - 80 PB - Pergamon-elsevier Science Ltd PY - 2014 SN - 0079-6565 ER -