Arginine dynamics probed by magic-angle spinning NMR with a specific isotope-labeling scheme Rohden, Darja Napoli, Federico ; https://orcid.org/0000-0002-9043-136X Kapitonova, Anna Tatman, Benjamin Lichtenecker, Roman J. Schanda, Paul ; https://orcid.org/0000-0002-9350-7606 ddc:540 The specific introduction of ^1H-^13C or ^1H-^15N moieties into otherwise deuterated proteins holds great potential for high-resolution solution and magic-angle spinning (MAS) NMR studies of protein structure and dynamics. Arginine residues play key roles for example at active sites of enzymes. Taking advantage of a chemically synthesized Arg with a ^13C-^1H2 group in an otherwise deuterated backbone, we demonstrate here the usefulness of proton-detected MAS NMR approaches to probe arginine dynamics. In experiments with crystalline ubiquitin and the 134 kDa tetrameric enzyme malate dehydrogenase we detected a wide range of motions, from sites that are rigid on time scales of at least tens of milliseconds to residues undergoing predominantly nanosecond motions. Spin-relaxation and dipolar-coupling measurements enabled quantitative determination of these dynamics. We observed microsecond dynamics of residue Arg54 in crystalline ubiquitin, whose backbone is known to sample different β-turn conformations on this time scale. The labeling scheme and experiments presented here expand the toolkit for high-resolution proton-detected MAS NMR. Elsevier 2025 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/20258 https://research-explorer.ista.ac.at/download/20258/20876 Rohden D, Napoli F, Kapitonova A, Tatman B, Lichtenecker RJ, Schanda P. Arginine dynamics probed by magic-angle spinning NMR with a specific isotope-labeling scheme. <i>Journal of Molecular Biology</i>. 2025;437(23). doi:<a href="https://doi.org/10.1016/j.jmb.2025.169379">10.1016/j.jmb.2025.169379</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.jmb.2025.169379 info:eu-repo/semantics/altIdentifier/issn/0022-2836 info:eu-repo/semantics/altIdentifier/e-issn/1089-8638 info:eu-repo/semantics/altIdentifier/wos/001618289100020 https://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess