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Nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography are the two main methods for protein three-dimensional structure determination at atomic resolution. According to the protein structures deposited in the Protein Data Bank, X-ray crystallography has become the dominant method for structure determination, particularly for large proteins and complexes. However, with the developments of isotope labeling, increase of magnetic field strength, common use of a cryogenic probe, and ingenious pulse sequence design, the applications of NMR spectroscopy have expanded in biological research, especially in characterizing protein dynamics, sparsely populated transient structures, weak protein interactions, and proteins in living cells at atomic resolution, which is difficult if not impossible by other biophysical methods. Although great advances have been made in protein NMR spectroscopy, its applications in protein therapeutics, which represents the fastest growing segment of the pharmaceutical industry, are still limited. Here we review the recent advances in the use of NMR spectroscopy in studies of large proteins or complexes, posttranslation modifications, weak interactions, and aggregation, and in-cell NMR spectroscopy. The potential applications of NMR spectroscopy in protein therapeutic assays are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Most proteins function in cells where protein concentrations can reach 400g/l. However, most quantitative studies of protein properties are performed in idealized, dilute conditions. Recently developed in-cell NMR techniques can provide protein structure and other biophysical properties inside living cells at atomic resolution. Here we review how protein dynamics, including global and internal motions have been characterized by in-cell NMR, and then discuss the remaining challenges and future directions. [Copyright &y& Elsevier]

A protein gel electrophoresis procedure using 0.05% w/v sarkosyl, is reported. The method called 05SAR-PAGE can be used to identify the native masses, dimeric states and modification states of proteins, and also be suitable for pursuing native electroblotting and immunodetection. It has been demonstrated by NMR spectroscopy that 0.05% w/v SAR is much milder than SDS, so it has subtle effects on the native structure of proteins. Therefore, the non-covalent dimerization of PhoB N and PhoR cp can be identified by 05SAR-PAGE which cannot be observed by SDS-PAGE. It has also been demonstrated that 05SAR-PAGE can be used to identify the phosphorylated or methylated proteins. Besides, 05SAR-PAGE shows the advantages of simple operation and low cost, and can be easily adapted to diverse applications. Image 1 • Determination of the dimerization states of PhoB N and PhoR cp by 05SAR-PAGE. • Mild effect of SAR on protein structure. • Western-blot of monomer and dimer states in vivo by 05SAR-PAGE. • Identification of different modification states of proteins by 05SAR-PAGE. [ABSTRACT FROM AUTHOR]