title: Efficient and precise measurement of H(alpha)-C(alpha), C(alpha)-C', C(alpha)-C(beta) and H(N)-N residual dipolar couplings from 2D H(N)-N correlation spectra.
abstract: A suite of experiments are presented for the measurement of H(alpha)-C(alpha), C(alpha)-C', C(alpha)-C(beta) and H(N)-N couplings from uniformly 15N, 13C labeled proteins. Couplings are obtained from a series of intensity modulated two-dimensional H(N)-N spectra equivalent to the common 1H-15N-HSQC spectra, alleviating many overlap and assignment issues associated with other techniques. To illustrate the efficiency of this method, H(alpha)-C(alpha), C(alpha)-C', and H(N)-N isotropic scalar couplings were determined for ubiquitin from data collected in less than 4.5 h, C(alpha)-C(beta) data collection required 10 h. The resulting couplings were measured with an average error of +/-0.06, +/-0.05, +/-0.04 and +/-0.10 Hz, respectively. This study also shows H(alpha)-C(alpha) and C(alpha)-C(beta) couplings, valuable because they provide orientation of bond vectors outside the peptide plane, can be measured in a uniform and precise way. Superior accuracy and precision to existing 3D measurements for C(alpha)-C' couplings and increased precision compared to IPAP measurements for H(N)-N couplings are demonstrated. Minor modifications allow for acquisition of modulated H(N)-C' 2D spectra, which can yield additional well resolved peaks and significantly increase the number of measured RDCs for proteins with crowded 1H-15N resonances.
authors.affiliation: Macromolecular NMR Section, Structural Biophysics Laboratory, National Cancer Institute, Frederick, MD 21702, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: McFeeters
authors.forename: C Andrew
authors.initials: CA
authors.lastname: Fowler
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Gaponenko
authors.forename: R Andrew
authors.initials: RA
authors.lastname: Byrd
mesh_terms: D002244:Carbon; D003627:Data Interpretation, Statistical; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009584:Nitrogen; D025801:Ubiquitin / Q000737:chemistry
chemical_list: D025801:Ubiquitin; D002244:Carbon; D006859:Hydrogen; D009584:Nitrogen