title: Accurate measurement of (3)J(HNHα) couplings in small or disordered proteins from WATERGATE-optimized TROSY spectra.
abstract: Provided that care is taken in adjusting the WATERGATE element of a (1)H-(15)N TROSY-HSQC experiment, such that neither the water magnetization nor the (1)H(α) protons are inverted by its final 180° pulse, (3)JHNHα couplings can be measured directly from splittings in the (1)H dimension of the spectrum. With band-selective (1)H decoupling, very high (15)N resolution can be achieved. A complete set of (3)JHNHα values, ranging from 3.4 to 10.1 Hz was measured for the 56-residue third domain of IgG-binding protein G (GB3). Using the H-N-C(α)-H(α) dihedral angles extracted from a RDC-refined structure of GB3, (3)JHNHα values predicted by a previously parameterized Karplus equation agree to within a root-mean-square deviation (rmsd) of 0.37 Hz with the experimental data. Values measured for the Alzheimer's implicated Aβ(1-40) peptide fit to within an rmsd of 0.45 Hz to random coil (3)JHNHα values.
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Julien
authors.initials: J
authors.lastname: Roche
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Jinfa
authors.initials: J
authors.lastname: Ying
authors.affiliation: Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Ad
authors.initials: A
authors.lastname: Bax
mesh_terms: D064267:Intrinsically Disordered Proteins / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011506:Proteins / Q000737:chemistry*
chemical_list: D064267:Intrinsically Disordered Proteins; D011506:Proteins
keywords: Abeta; IDP; Karplus curve; Protein NMR; Random coil; Synuclein