title: Magic angle spinning NMR of proteins: high-frequency dynamic nuclear polarization and (1)H detection.
abstract: Magic angle spinning (MAS) NMR studies of amyloid and membrane proteins and large macromolecular complexes are an important new approach to structural biology. However, the applicability of these experiments, which are based on (13)C- and (15)N-detected spectra, would be enhanced if the sensitivity were improved. Here we discuss two advances that address this problem: high-frequency dynamic nuclear polarization (DNP) and (1)H-detected MAS techniques. DNP is a sensitivity enhancement technique that transfers the high polarization of exogenous unpaired electrons to nuclear spins via microwave irradiation of electron-nuclear transitions. DNP boosts NMR signal intensities by factors of 10(2) to 10(3), thereby overcoming NMR's inherent low sensitivity. Alternatively, it permits structural investigations at the nanomolar scale. In addition, (1)H detection is feasible primarily because of the development of MAS rotors that spin at frequencies of 40 to 60 kHz or higher and the preparation of extensively (2)H-labeled proteins.
authors.affiliation: Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; email: rgg@mit.edu.
authors.forename: Yongchao
authors.initials: Y
authors.lastname: Su
authors.forename: Loren
authors.initials: L
authors.lastname: Andreas
authors.forename: Robert G
authors.initials: RG
authors.lastname: Griffin
mesh_terms: D000682:Amyloid / Q000737:chemistry; D001419:Bacteria / Q000737:chemistry; D006801:Humans; D006859:Hydrogen / Q000032:analysis; D008565:Membrane Proteins / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000295:instrumentation / Q000379:methods*
chemical_list: D000682:Amyloid; D008565:Membrane Proteins; D006859:Hydrogen
keywords: 1H detection; NMR; amyloid fibrils; dynamic nuclear polarization; membrane proteins; protein structure