Keyang Ding

National Institutes of Health, Bethesda, MD, United States

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Publications (9)36.76 Total impact

  • Keyang Ding, Angela M Gronenborn
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    ABSTRACT: A simple, sensitivity-enhanced experiment was devised for accurate measurement of backbone 15N-13Calpha and 1HN-13Calpha couplings in proteins. The measured residual dipolar couplings 2DHCA, 1DNCA, 3DHCA, and 2DNCA for protein GB1 display very good agreement with the refined NMR structure (PDB code: 3GB1). A Karplus-type relationship between the one-bond 1JNCA couplings and the backbone dihedral psi angles holds, and on the basis of the two-bond 2JNCA couplings a secondary structure index can be established.
    Journal of the American Chemical Society 06/2004; 126(20):6232-3. · 10.68 Impact Factor
  • Keyang Ding, Angela M Gronenborn
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    ABSTRACT: Sensitivity-enhanced 2D IPAP experiments using the accordion principle for measuring one-bond 13C'-13Calpha and 1Halpha-13Calpha dipolar couplings in proteins are presented. The resolution of the resulting spectra is identical to that of the decoupled HSQC spectra and the sensitivity of the corresponding 1D acquisitions are only slightly lower than those obtained with 3D HNCO and 3D HN(COCA)HA pulse sequences due to an additional delay 2Delta. For cases of limited resolution in the 2D 15N-1HN HSQC spectrum the current pulse sequences can easily be modified into 3D versions by introducing a poorly digitized third dimension, if so desired. The experiments described here are a valuable addition to the suites available for determination of residual dipolar couplings in biological systems.
    Journal of Magnetic Resonance 05/2004; 167(2):253-8. · 2.30 Impact Factor
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    ABSTRACT: Understanding protein stability requires characterization of structural determinants of the folded and unfolded states. Many proteins are capable of populating partially folded states under specific solution conditions. Occasionally, coexistence of the folded and an unfolded state under non- or mildly denaturing conditions can be observed by NMR, allowing us to structurally probe these states under identical conditions. Here we report on a destabilized mutant of the B1 domain of protein G (GB1) whose equilibrium unfolding was systematically investigated. Backbone amide residual dipolar couplings (RDCs), the tryptophan Nepsilon-H resonance and the amide nitrogen transverse relaxation rates (R2s) for varying pH values and different temperatures were measured. The backbone amide RDCs indicate that prior to complete unfolding, two melting hot spots are formed at the turn around T11, L12 and K13 and the N terminus of the helix at A24 and T25. The RDCs for the low pH, thermally unfolded state of GB1 are very small and do not indicate the presence of any native-like structure. Amide nitrogen transverse relaxation rates for GB1 in the folded state at different temperatures exhibit large contributions from exchange processes and the associated dynamics display considerable heterogeneity. Our data provide clear evidence for intermediate conformations and multi-state equilibrium un/folding for this GB1 variant.
    Journal of Molecular Biology 02/2004; 335(5):1299-307. · 3.91 Impact Factor
  • Keyang Ding, Angela M Gronenborn
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    ABSTRACT: Using the echo-anti-echo manipulation, the 15N-1HN cross-peaks split in the E.COSY spectrum by the 13CO couplings are separated into different, distinct regions in the HSQC spectrum. From this novel E.COSY 15N-1HN HSQC spectrum, the small one-bond 15N-13C' and two-bond 1HN-13C' residual dipolar couplings can be extracted easily and accurately. These dipolar couplings provide a set of important long-range constraints for protein structure determination.
    Journal of the American Chemical Society 10/2003; 125(38):11504-5. · 10.68 Impact Factor
  • Keyang Ding, Angela M Gronenborn
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    ABSTRACT: Sensitivity-enhanced versions of the IPAP, TROSY-anti-TROSY, and E.COSY experiments for measuring one-bond 15N-1HN couplings are presented. Together with the previously developed sensitivity-enhanced E.COSY-type HSQC experiment they comprise a suite of sensitivity-enhanced experiments that allows one to chose the optimal spectrum for accurate measurement of one-bond 15N-1HN residual dipolar couplings in proteins. Since one-bond 15N-1HN residual dipolar couplings play uniquely important roles in structural NMR, these additional methods provide further tools for improving structure determination of proteins and other biological macromolecules.
    Journal of Magnetic Resonance 09/2003; 163(2):208-14. · 2.30 Impact Factor
  • Keyang Ding, Angela M. Gronenborn
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    ABSTRACT: Sensitivity-enhanced versions of the IPAP, TROSY–anti-TROSY, and E.COSY experiments for measuring one-bond 15N–1HN couplings are presented. Together with the previously developed sensitivity-enhanced E.COSY-type HSQC experiment they comprise a suite of sensitivity-enhanced experiments that allows one to chose the optimal spectrum for accurate measurement of one-bond 15N–1HN residual dipolar couplings in proteins. Since one-bond 15N–1HN residual dipolar couplings play uniquely important roles in structural NMR, these additional methods provide further tools for improving structure determination of proteins and other biological macromolecules.
    Journal of Magnetic Resonance - J MAGN RESON. 01/2003; 163(2):208-214.
  • Keyang Ding, Angela M. Gronenborn
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    ABSTRACT: Novel E.COSY-type HSQC experiments are presented for the accurate measurement of one-bond 15N- 1HN and 15N- 13C' and two-bond 13C'- 1HN residual dipolar couplings in proteins. Compared with existing experiments, the ( δ, J)-E.COSY experiments described here are composed of fewer pulses and the resulting spectra exhibit 1.4 times the sensitivity of coupled HSQC spectra. Since residual dipolar couplings play increasingly important roles in structural NMR, the proposed methods should find wide spread application for structure determination of proteins and other biological macromolecules.
    Journal of Magnetic Resonance 09/2002; 158(1-2):173-177. · 2.30 Impact Factor
  • Keyang Ding, Angela M Gronenborn
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    ABSTRACT: We present 2D versions of the popular triple resonance HN(CO) CACB, HN(COCA)CACB, HN(CO)CAHA, and HN(COCA) CAHA experiments, commonly used for sequential resonance assignments of proteins. These experiments provide information about correlations between amino proton and nitrogen chemical shifts and the alpha- and beta-carbon and alpha-proton chemical shifts within and between amino acid residues. Using these 2D spectra, sequential resonance assignments of H(N), N, C(alpha), C(beta), and H(alpha) nuclei are easily achieved. The resolution of these spectra is identical to the well-resolved 2D (15)N-(1)H HSQC and H(NCO)CA spectra, with slightly reduced sensitivity compared to their 3D and 4D versions. These types of spectra are ideally suited for exploitation in automated assignment procedures and thereby constitute a fast and efficient means for NMR structural determination of small and medium-sized proteins in solution in structural genomics programs.
    Journal of Magnetic Resonance 07/2002; 156(2):262-8. · 2.30 Impact Factor
  • Keyang Ding, Angela M Gronenborn
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    ABSTRACT: Novel E.COSY-type HSQC experiments are presented for the accurate measurement of one-bond 15N-1H(N) and 15N-13C(') and two-bond 13C(')-1H(N) residual dipolar couplings in proteins. Compared with existing experiments, the (delta,J)-E.COSY experiments described here are composed of fewer pulses and the resulting spectra exhibit 1.4 times the sensitivity of coupled HSQC spectra. Since residual dipolar couplings play increasingly important roles in structural NMR, the proposed methods should find wide spread application for structure determination of proteins and other biological macromolecules.
    Journal of Magnetic Resonance 01/2002; 158(1-2):173-7. · 2.30 Impact Factor

Publication Stats

156 Citations
36.76 Total Impact Points

Institutions

  • 2002–2004
    • National Institutes of Health
      • Laboratory of Chemical Physics (LCP)
      Bethesda, MD, United States