Datensatz

Zusammenfassung

Solid-state Nuclear Magnetic Resonance can provide detailed insight into structural and dynamical aspects of complex biomolecules. With increasing molec- ular size, advanced approaches for spectral simplification and the detection of medium to long-range contacts become of critical relevance. We have analyzed the pro- tonation pattern of a membrane-embedded ion channel that was obtained from bacterial expression using protonated precursors and D 2 O medium. We find an overall reduction of 50% in protein protonation. High levels of deuteration at H a and H b positions reduce spectral congestion in ( 1 H, 13 C, 15 N) correlation experiments and generate a transfer profile in longitudinal mixing schemes that can be tuned to specific resonance frequencies. At the same time, residual protons are predominantly found at amino-acid side-chain positions enhancing the prospects for obtaining side-chain resonance assignments and for detecting med- ium to long-range contacts. Fractional deuteration thus provides a powerful means to aid the structural analysis of complex biomolecules by solid-state NMR.