Solid-state NMR spectroscopy of oriented membrane polypeptides at 100 K with signal enhancement by dynamic nuclear polarization.
Oriented membrane samples encompassing the biradical bTbK and a transmembrane peptide carrying a single (15)N labeled residue have been prepared on polymer sheets with sample geometries that fit into a 3.2 mm MAS rotor. The proton-decoupled (15)N cross-polarization spectra of the peptide were characterized by a single line at fast magic angle spinning speeds of approximately 8 kHz. Irradiating these samples with mu-waves resulted in Dynamic Nuclear Polarization and a concomitant 18-fold signal enhancement which considerably shortened the NMR acquisition times. Furthermore, the sideband patterns of magic angle oriented sample spinning (MAOSS) solid-state NMR spectra at slow spinning speeds (approximately 1 kHz) are indicative that the lipids and peptides form well-oriented bilayers at 100 K despite the narrow inner diameter of the rotor (2.2 mm) and the presence of considerable amounts of biradicals. The DNP signal enhancement opens up enhanced possibilities for multidimensional solid-state NMR investigation of oriented membrane polypeptides.
Salnikov
Evgeniy
E
Insitut de Chimie, Université de Strasbourg-CNRS UMR7177, 4 rue Blaise Pascal, 67070 Strasbourg, France.
Rosay
Melanie
M
Pawsey
Shane
S
Ouari
Olivier
O
Tordo
Paul
P
Bechinger
Burkhard
B
D000595:Amino Acid Sequence; D008565:Membrane Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*
D008565:Membrane Proteins; D010455:Peptides