title: Distance and dynamics determination by W-band DEER and W-band ST-EPR.
abstract: To explore high-field EPR in biological applications we have compared measurements of dynamics with X-band (9 GHz) and W-band (94 GHz) saturation transfer EPR (ST-EPR) and distance determination by X and W-band DEER. A fourfold increase of sensitivity was observed for W-band ST-EPR compared with X-band. The distance measurements at both fields showed very good agreement in both the average distances and in the distance distributions. Multifrequency EPR thus provides an additional experimental dimension to facilitate extraction of distance populations. However, the expected orientational selectivity of W-band DEER to determine the relative orientation of spins has not been realized, most likely because of the large orientational disorder of spin labels on the protein surface.
authors.affiliation: National High Magnetic Field Laboratory, Institute of Molecular Biophysics, Department of Biological Science, Department of Biochemistry and Chemistry, Florida State University, Tallahassee, FL 32310, USA.
authors.forename: Likai
authors.initials: L
authors.lastname: Song
authors.forename: Mioara
authors.initials: M
authors.lastname: Larion
authors.forename: Jean
authors.initials: J
authors.lastname: Chamoun
authors.forename: Marco
authors.initials: M
authors.lastname: Bonora
authors.forename: Piotr G
authors.initials: PG
authors.lastname: Fajer
mesh_terms: D004058:Diffusion; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006454:Hemoglobins / Q000737:chemistry; D008872:Microwaves; D013696:Temperature; D014783:Viscosity
chemical_list: D006454:Hemoglobins