Combining Multinuclear High-Resolution Solid-State MAS NMR and Computational Methods for Resonance Assignment of Glutathione Tripeptide

We present a complete set of experimental approaches for the NMR assignment of powdered tripeptide glutathione at natural isotopic abundance, based on J-coupling and dipolar NMR techniques combined with H-1 CRAMPS decoupling. To fully assign the spectra, two-dimensional (2D) high-resolution methods, such as H-1-C-13 INEPT-HSQC/PRESTO heteronuclear correlations (HETCOR) H-1-H-1, double-quantum (DQ), and H-1-N-14 D-HMQC correlation experiments, have been used. To support the interpretation of the experimental data, periodic density functional theory calculations together with the GIPAW approach have been used to calculate the H-1 and C-13 chemical shifts. It is found that the shifts calculated with two popular plane wave codes (CASTEP and Quantum ESPRESSO) are in excellent agreement with the experimental results.