Cross-Polarization Schemes for Improved Heteronuclear Transfers Involving Labile Protons in Biomolecular Solution NMR
Abstract
INEPT-based experiments are widely used for ¹H→¹⁵N transfers, but often fail when involving labile protons due to solvent exchanges. J-based cross polarization (CP) strategies offer a more efficient alternative to perform such transfers, particularly when leveraging the Hʷᵃᵗᵉʳ ↔ Hᴺ exchange process to boost the ¹H→¹⁵N transfer process. This leveraging, however, demands the simultaneous spin-locking of both Hʷᵃᵗᵉʳ and Hᴺ protons by a strong ¹H RF field, while fulfilling the γₕB₁,ₕ=γₙB₁,ₙ Hartmann-Hahn matching condition. Given the low value of γₙ/γₕ, however, these demands are often incompatible—particularly when experiments are executed by the power-limited cryogenic probes used in contemporary high field NMR. The present manuscript discusses CP alternatives that can alleviate this limitation, and evaluates their performance on urea, amino acids, and intrinsically disordered proteins. These alternatives include new CP variants based on frequency-swept and phase-modulated pulses, designed to simultaneously fulfill the aforementioned conflicting conditions. Their performances vis-à-vis current options are theoretically analyzed with Liouville-space simulations, and experimentally tested with double and triple resonance transfer experiments. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000624574Publication status
publishedExternal links
Journal / series
Angewandte Chemie. International EditionVolume
Pages / Article No.
Publisher
Wiley-VCHSubject
Adiabatic Sweeps; Chemical Exchange; Cross Polarization; INEPT; Intrinsically Disordered ProteinsMore
Show all metadata
ETH Bibliography
yes
Altmetrics