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

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 H-2, C-13, and N-15 isotope labelling, effectively diluting 1H spins. In many cases, a sufficient amount of H-1 at exchangeable sites cannot be re-established during the purification procedure, hence it is necessary to exploit also the potential of H-2 as a starting point in pulse sequences, capitalizing on its short T-1 as compared to C-13, and to detect carbon or proton spins as appropriate. Here we present a new method that enables the required high-efficiency H-2, C-13, and N-15 polarization transfer to be accomplished under the limited H-2 rf power conditions using current H-1, H-2, C-13 and N-15 quadruple-resonance MAS NMR instrumentation.