title: Mapping membrane protein backbone dynamics: a comparison of site-directed spin labeling with NMR 15N-relaxation measurements.
abstract: The ability to detect nanosecond backbone dynamics with site-directed spin labeling (SDSL) in soluble proteins has been well established. However, for membrane proteins, the nitroxide appears to have more interactions with the protein surface, potentially hindering the sensitivity to backbone motions. To determine whether membrane protein backbone dynamics could be mapped with SDSL, a nitroxide was introduced at 55 independent sites in a model polytopic membrane protein, TM0026. Electron paramagnetic resonance spectral parameters were compared with NMR (15)N-relaxation data. Sequential scans revealed backbone dynamics with the same trends observed for the R1 relaxation rate, suggesting that nitroxide dynamics remain coupled to the backbone on membrane proteins.
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, Virginia.
authors.forename: Ryan H
authors.initials: RH
authors.lastname: Lo
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, Virginia.
authors.forename: Brett M
authors.initials: BM
authors.lastname: Kroncke
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, Virginia.
authors.forename: Tsega L
authors.initials: TL
authors.lastname: Solomon
authors.affiliation: Department of Chemistry, University of Virginia, Charlottesville, Virginia. Electronic address: columbus@virginia.edu.
authors.forename: Linda
authors.initials: L
authors.lastname: Columbus
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009589:Nitrogen Oxides / Q000737:chemistry; D013113:Spin Labels
chemical_list: D008565:Membrane Proteins; D009589:Nitrogen Oxides; D013113:Spin Labels; C039900:nitroxyl