Fast magic angle spinning NMR with heteronucleus detection for resonance assignments and structural characterization of fully protonated proteins.

Heteronucleus-detected dipolar based correlation spectroscopy is established for assignments of ¹H, ¹³C, and ¹⁵N resonances and structural analysis in fully protonated proteins. We demonstrate that ¹³C detected 3D experiments are highly efficient and permit assignments of the majority of backbone resonances, as shown in an 89-residue dynein light chain 8, LC8 protein. With these experiments, we have resolved many ambiguities that were persistent in our previous studies using moderate MAS frequencies and lacking the ¹H dimension. The availability of ¹H isotropic chemical shifts measured with the heteronucleus-detected fast-MAS experiments presented here is essential for the accurate determination of the ¹H CSA tensors, which provide very useful structural probe. Finally, our results indicate that ¹³C detection in fast-MAS HETCOR experiments may be advantageous compared with ¹H detection as it yields datasets of significantly higher resolution in the ¹³C dimension than the ¹H detected HETCOR versions.