Conformational Dynamics in the Core of Human Y145Stop Prion Protein Amyloid Probed by Relaxation Dispersion NMR

International audienceMicrosecond to millisecond timescale backbone dynamics of the amyloid core residues in Y145Stop human prion protein (PrP) fibrils were investigated by using 15 N rotating frame (R1r) relaxation dispersion solid-state nuclear magnetic resonance spectroscopy over a wide range of spin-lock fields. Numerical simulations enabled the experimental relaxation dispersion profiles for most of the fibril core residues to be modelled by using a two-state exchange process with a common exchange rate of 1,000 s-1 , corresponding to protein backbone motion on the timescale of 1 ms, and an excited-state population of 2%. We also found that the relaxation dispersion profiles for several amino acids positioned near the edges of the most structured regions of the amyloid core were better modelled by assuming somewhat higher excited-state populations (~5-15%) and faster exchange rate constants, corresponding to protein backbone motions on the timescale of ~100-300 µs. The slow backbone dynamics of the core residues were evaluated in the context of the structural model of human Y145Stop PrP amyloid

Rapid Quantitative Measurements of Paramagnetic Relaxation Enhancements in Cu(II)-Tagged Proteins by Proton-Detected Solid-State NMR Spectroscopy

We demonstrate rapid quantitative measurements of site-resolved paramagnetic relaxation enhancements (PREs), which are a source of valuable structural restraints corresponding to electron–nucleus distances in the ∼10–20 Å regime, in solid-state nuclear magnetic resonance (NMR) spectra of proteins containing covalent Cu²⁺-binding tags. Specifically, using protein GB1 K28C-EDTA-Cu²⁺ mutant as a model, we show the determination of backbone amide ¹⁵N longitudinal and ¹H transverse PREs within a few hours of experiment time based on proton-detected 2D or 3D correlation spectra recorded with magic-angle spinning frequencies ≥ ∼ 60 kHz for samples containing ∼10–50 nanomoles of ²H,¹³C,¹⁵N-labeled protein back-exchanged in H₂O. Additionally, we show that the electron relaxation time for the Cu²⁺ center, needed to convert PREs into distances, can be estimated directly from the experimental data. Altogether, these results are important for establishing solid-state NMR based on paramagnetic-tagging as a routine tool for structure determination of natively diamagnetic proteins

Chemoselective umpolung of thiols to episulfoniums for cysteine bioconjugation

MS Raw Data. Each MS raw spectrum was named, based on the used protein and the corresponding reaction. The assignment will be added shorty. Currently, the assignment can be provided by Philipp Hartmann ([email protected])

Author Correction: Chemoselective umpolung of thiols to episulfoniums for cysteine bioconjugation

Hartmann P, Bohdan K, Hommrich M, et al. Author Correction: Chemoselective umpolung of thiols to episulfoniums for cysteine bioconjugation. Nature chemistry. 2024