Abstract
Magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy is emerging as a unique method for the atomic resolution structure determination of native membrane proteins in lipid bilayers. Although 13C-detected ssNMR experiments continue to play a major role, recent technological developments have made it possible to carry out 1H-detected experiments, boosting both sensitivity and resolution. Here, we describe a new set of 1H-detected hybrid pulse sequences that combine through-bond and through-space correlation elements into single experiments, enabling the simultaneous detection of rigid and dynamic domains of membrane proteins. As proof-of-principle, we applied these new pulse sequences to the membrane protein phospholamban (PLN) reconstituted in lipid bilayers under moderate MAS conditions. The cross-polarization (CP) based elements enabled the detection of the relatively immobile residues of PLN in the transmembrane domain using through-space correlations; whereas the most dynamic region, which is in equilibrium between folded and unfolded states, was mapped by through-bond INEPT-based elements. These new 1H-detected experiments will enable one to detect not only the most populated (ground) states of biomacromolecules, but also sparsely populated high-energy (excited) states for a complete characterization of protein free energy landscapes.
Original language | English (US) |
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Pages (from-to) | 101-107 |
Number of pages | 7 |
Journal | Journal of Magnetic Resonance |
Volume | 285 |
DOIs | |
State | Published - Dec 2017 |
Bibliographical note
Funding Information:This work is supported by the National Institutes of Health ( GM 64742 and GM 72701 ). The NMR experiments were carried out at the Minnesota NMR Center.
Publisher Copyright:
© 2017 Elsevier Inc.
Keywords
- Conformationally excited states
- DUMAS
- Membrane proteins
- Simultaneous acquisitions
- cpHSQC
- riHSQC