Transverse-Dephasing Optimized Homonuclear J-Decoupling in Solid-State NMR Spectroscopy of Uniformly 13C-Labeled Proteins
Sgolne Laage†, Anne Lesage†, Lyndon Emsley†, Ivano Bertini‡, Isabella C. Felli‡, Roberta Pierattelli‡ and Guido Pintacuda*†
A transverse-dephasing optimized S3E (spin-state selective excitation) method is implemented in solid-state NMR experiments of uniformly labeled protein samples, and it is shown to provide a simultaneous significant gain in both resolution (up to a factor of 2.2) and sensitivity (up to a factor of 1.4). This is illustrated with high-resolution NCO and NCA correlations of a microcrystalline sample of the oxidized form of the 153 residue human Cu(II)Zn(II) superoxide dismutase (SOD), a dimeric paramagnetic enzyme of 32 kDa. This method allows the resolution of 145 signals in the highly crowded carbonyl region in the NCO correlation spectrum.