Collecting Large Datasets of Unambiguous Structural Restraints for Protein Structure Determination by 4D Proton‐Detected Solid‐State NMR

Solid-state magic-angle spinning NMR is a powerful technique for obtaining atomic-resolution structural information of different types of biological macromolecules. The relatively low sensitivity and limited resolution of this method have continuously stimulated methodological developments to broaden its application range. In this study, we efficiently apply proton detection, moderate sample rotation, nonuniform sampling in four-dimensional spectra, multiplexing, deuteration, and stereospecific labeling of methyl groups to collect several hundred unambiguous long-range distance restraints based on proton-proton magnetization transfers. These data provide a reliable description of the core domain structure of full-length bactofilin BacA, which belongs to a newly discovered class of cytoskeletal proteins. The work demonstrates the power of combining available techniques for fast and reliable atomic-level structural investigations that can be applied to a wide range of proteins.