Research data to: The rigid core and flexible surface of amyloid fibrils probed by magic-angle-spinning NMR spectroscopy of aromatic residues Becker, Lea Marie ; https://orcid.org/0000-0002-6401-5151 Schanda, Paul ; https://orcid.org/0000-0002-9350-7606 aromatic side chains isotopic labeling protein dynamics ring flips spin relaxation ddc:572 Aromatic side chains are important reporters of the plasticity of proteins, and often form important contacts in protein–protein interactions. We studied aromatic residues in the two structurally homologous cross-β amyloid fibrils HET-s, and HELLF by employing a specific isotope-labeling approach and magic-angle-spinning NMR. The dynamic behavior of the aromatic residues Phe and Tyr indicates that the hydrophobic amyloid core is rigid, without any sign of "breathing motions" over hundreds of milliseconds at least. Aromatic residues exposed at the fibril surface have a rigid ring axis but undergo ring flips on a variety of time scales from nanoseconds to microseconds. Our approach provides direct insight into hydrophobic-core motions, enabling a better evaluation of the conformational heterogeneity generated from an NMR structural ensemble of such amyloid cross-β architecture. Institute of Science and Technology Austria 2023 info:eu-repo/semantics/other doc-type:ResearchData text http://purl.org/coar/resource_type/63NG-B465 https://research-explorer.ista.ac.at/record/12497 https://research-explorer.ista.ac.at/download/12497/12743 https://research-explorer.ista.ac.at/download/12497/12755 Becker LM, Schanda P. Research data to: The rigid core and flexible surface of amyloid fibrils probed by magic-angle-spinning NMR spectroscopy of aromatic residues. 2023. doi:<a href="https://doi.org/10.15479/AT:ISTA:12497">10.15479/AT:ISTA:12497</a> info:eu-repo/semantics/altIdentifier/doi/10.15479/AT:ISTA:12497 https://creativecommons.org/licenses/by-nc/4.0/ info:eu-repo/semantics/openAccess