Deuteron Quadrupolar Chemical Exchange Saturation Transfer (Q‐CEST) Solid‐State NMR for Static Powder Samples: Approach and Applications to Amyloid‐β Fibrils
| Autor: | Dmitry Ostrovsky, Riqiang Fu, Liliya Vugmeyster |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Deuterium NMR
Materials science Protein Conformation Proton Magnetic Resonance Spectroscopy 010402 general chemistry Fibril 01 natural sciences Article chemistry.chemical_compound 0103 physical sciences Amino Acid Sequence Physical and Theoretical Chemistry Nuclear Magnetic Resonance Biomolecular Amyloid beta-Peptides 010304 chemical physics Chemical exchange Deuterium Peptide Fragments Atomic and Molecular Physics and Optics 0104 chemical sciences Models Chemical Solid-state nuclear magnetic resonance chemistry Chemical physics Saturation transfer Shape analysis (digital geometry) Methyl group |
| Zdroj: | Chemphyschem |
| ISSN: | 1439-7641 1439-4235 |
| Popis: | We provide an experimental and computational framework for (2)H quadrupolar chemical exchange saturation transfer NMR experiments (Q-CEST) under static solid-state conditions for the quantification of dynamics on μs-ms timescales. Simulations using simple 2-site exchange models provide insights into the relation between spin dynamics and motions. Biological applications focus on two sites of amyloid-β fibrils in the 3-fold symmetric polymorph. The first site, the methyl group of A2 of the disordered N-terminal domain, undergoes diffusive motions and conformational exchange due to transient interactions. Earlier (2)H rotating frame relaxation and quadrupolar CPMG measurements are combined with the Q-CEST approach to characterize the multiple conformational states of the domain. The second site, the methyl group of M35, spans the water-accessible cavity inside the fibrils’ core and undergoes extensive rotameric exchange. Q-CEST permits us to refine the rotameric exchange model for this site and allows the more precise determination of populations and rotameric exchange rate constants than line shape analysis. |
| Databáze: | OpenAIRE |
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