Low-power polarization transfer between deuterons and spin-1/2 nuclei using adiabatic RESPIRATIONCP in solid-state NMR

Abstract

Establishing high-resolution structures of biological macromolecules in heterogeneous environments by MAS solid-state NMR is an important challenge where development of advanced experimental procedures is in high demand. Promising new methods take advantage of samples with extensive ²H, ¹³C, and ¹⁵N isotope labelling, effectively diluting ¹H spins. In many cases, a sufficient amount of ¹H at exchangeable sites cannot be re-established during the purification procedure, hence it is necessary to exploit also the potential of ²H as a starting point in pulse sequences, capitalizing on its short T₁ as compared to ¹³C, and to detect carbon or proton spins as appropriate. Here we present a new method that enables the required high-efficiency ²H to ¹³C or ¹⁵N polarization transfer to be accomplished under the limited ²H rf power conditions using current ¹H, ²H, ¹³C and ¹⁵N quadruple-resonance MAS NMR instrumentation.