Aromatic spectral editing techniques for magic-angle-spinning solid-state NMR spectroscopy of uniformly C-13-labeled proteins

作者：Williams Jonathan K; Schmidt Rohr Klaus; Hong Mei^*

来源：Solid State Nuclear Magnetic Resonance, 2015, 72: 118-126.

DOI：10.1016/j.ssnmr.2015.09.006

• Aromatic residues
• Gated decoupling
• ASSET
• PDSD

The four aromatic amino acids in proteins, namely histidine, phenylalanine, tyrosine, and tryptophan, have strongly overlapping C-13 chemical shift ranges between 100 and 160 ppm, and have so far been largely neglected in solid-state NMR determination of protein structures. Yet aromatic residues play important roles in biology through pi-pi and cation-pi interactions. To better resolve and assign aromatic residues' C-13 signals in magic-angle-spinning (MAS) solid-state NMR spectra, we introduce two spectral editing techniques. The first method uses gated H-1 decoupling in a proton-driven spin-diffusion (PDSD) experiment to remove all protonated C-13 signals and retain only non-protonated carbon signals in the aromatic region of the C-13 spectra. The second technique uses chemical shift filters and H-1-C-13 dipolar dephasing to selectively detect the C alpha, C beta and CO cross peaks of aromatic residues while suppressing the signals of all aliphatic residues. We demonstrate these two techniques on amino acids, a model peptide, and the microcrystalline protein GB1, and show that they significantly simplify the 2D NMR spectra and both reveal and permit the ready assignment of the aromatic residues' signals.

• 出版日期2015-11
• 单位MIT