A device for the measurement of residual chemical shift anisotropy and residual dipol
Abstract Residual dipolar coupling (RDC) and residual chemical shift anisotropy (RCSA) report on orientational properties of a dipolar bond vector and a chemical shift anisotropy principal axis system, respectively. They can be highly complementary in the analysis of backbone structure and dynamics in proteins as RCSAs generally include a report on vectors out of a peptide plane while RDCs usually report on in-plane vectors. Both RDC and RCSA average to zero in isotropic solutions and require partial orientation in a magnetic field to become observable. While the alignment and measurement of RDC has become routine, that of RCSA is less common. This is partly due to difficulties in providing a suitable isotopic reference spectrum for the measurement of the small chemical shift offsets coming from RCSA. Here we introduce a device (modified NMR tube) specifically designed for accurate measurement of reference and aligned spectra for RCSA measurements, but with a capacity for RDC measurements as well. Applications to both soluble and membrane anchored proteins are illustrated.
Content Type Journal Article
DOI 10.1007/s10858-010-9427-7
Authors
Yizhou Liu, The University of Georgia Complex Carbohydrate Research Center Athens GA 30602 USA
James H. Prestegard, The University of Georgia Complex Carbohydrate Research Center Athens GA 30602 USA
Simultaneous measurement of 1Hâ??15N and Methyl 1Hmâ??13Cm residual dipolar couplings in large proteins
Simultaneous measurement of 1Hâ??15N and Methyl 1Hmâ??13Cm residual dipolar couplings in large proteins
Abstract A two-dimensional TROSY-based SIM-13Cmâ??1Hm/1Hâ??15N NMR experiment for simultaneous measurements of methyl 1 D CH and backbone amide 1 D NH residual dipolar couplings (RDC) in {U-; Ileδ1-; Leu,Val-}-labeled samples of large proteins is described. Significant variation in the alignment tensor of the 82-kDa enzyme Malate synthase G is observed as a function of only slight changes in experimental conditions. The SIM-13Cmâ??1Hm/1Hâ??15N data sets provide convenient means...
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09-30-2011 08:01 PM
Measurement of 1Hâ??15N and 1Hâ??13C residual dipolar couplings in nucleic acids from TROSY intensities
Measurement of 1Hâ??15N and 1Hâ??13C residual dipolar couplings in nucleic acids from TROSY intensities
Abstract Analogous to the recently introduced ARTSY method for measurement of one-bond 1Hâ??15N residual dipolar couplings (RDCs) in large perdeuterated proteins, we introduce methods for measurement of base 13Câ??1H and 15Nâ??1H RDCs in protonated nucleic acids. Measurements are based on quantitative analysis of intensities in 1Hâ??15N and 13Câ??1H TROSY-HSQC spectra, and are illustrated for a 71-nucleotide adenine riboswitch. Results compare favorably with those of conventional...
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09-30-2011 08:01 PM
Rapid measurement of residual dipolar couplings for fast fold elucidation of proteins
Rapid measurement of residual dipolar couplings for fast fold elucidation of proteins
Abstract It has been demonstrated that protein folds can be determined using appropriate computational protocols with NMR chemical shifts as the sole source of experimental restraints. While such approaches are very promising they still suffer from low convergence resulting in long computation times to achieve accurate results. Here we present a suite of time- and sensitivity optimized NMR experiments for rapid measurement of up to six RDCs per residue. Including such an RDC data set, measured in less...
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09-17-2011 10:20 AM
Calculation of chemical shift anisotropy in proteins
Calculation of chemical shift anisotropy in proteins
Abstract Individual peptide groups in proteins must exhibit some variation in the chemical shift anisotropy (CSA) of their constituent atoms, but not much is known about the extent or origins of this dispersion. Direct spectroscopic measurement of CSA remains technically challenging, and theoretical methods can help to overcome these limitations by estimating shielding tensors for arbitrary structures. Here we use an automated fragmentation quantum mechanics/molecular mechanics (AF-QM/MM) approach to compute 15N, 13Câ?² and 1H...
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08-29-2011 06:41 AM
Facile measurement of 1Hâ??15N residual dipolar couplings in larger perdeuterated pro
Abstract We present a simple method, ARTSY, for extracting 1JNH couplings and 1Hâ??15N RDCs from an interleaved set of two-dimensional 1Hâ??15N TROSY-HSQC spectra, based on the principle of quantitative J correlation. The primary advantage of the ARTSY method over other methods is the ability to measure couplings without scaling peak positions or altering the narrow line widths characteristic of TROSY spectra. Accuracy of the method is demonstrated for the model system GB3. Application to the catalytic core domain of HIV integrase, a 36 kDa homodimer with unfavorable spectral...
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08-14-2010 04:19 AM
MQ-HNCO-TROSY for the measurement of scalar and residual dipolar couplings in larger
Abstract We describe a novel pulse sequence, MQ-HNCO-TROSY, for the measurement of scalar and residual dipolar couplings between amide proton and nitrogen in larger proteins. The experiment utilizes the whole 2TN polarization transfer delay for labeling of 15N chemical shift in a constant time manner, which efficiently doubles the attainable resolution in 15N dimension with respect to the conventional HNCO-TROSY experiment. In addition, the accordion principle is employed for measuring (J + D)NHs, and the multiplet components are selected with the generalized version of the TROSY scheme...
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08-14-2010 04:19 AM
chemical shift anisotropy (CSA) in model-free approach
Hi !
I have a quite general question about the value used for the CSA while studying protein dynamics of 15N-1H vectors with model-free approach.
In the litterature, we mainly find two values for the CSA (-160 and -172 ppm).
There is, if I understand well, a link between the bond length and the CSA, but everyone seems to agree about using the same value of 1.02 A which should give rise to a mean S2 of 0.85 for secondary structure when combined to a CSA of -172 ppm. When using a CSA of -160 ppm, the mean S2 for secondary structure should slightly rise up from 0.85.
The manuals for...
semor
NMR Questions and Answers
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09-29-2006 12:08 AM
Composite Alignment Media for the Measurement of Independent Sets of NMR Residual Dipolar Couplings
Composite Alignment Media for the Measurement of Independent Sets of NMR Residual Dipolar Couplings
Ke Ruan and Joel R. Tolman
J. Am. Chem. Soc.; 2005; 127(43) pp 15032 - 15033;
Abstract:
The measurement of independent sets of NMR residual dipolar couplings (RDCs) in multiple alignment media can provide a detailed view of biomolecular structure and dynamics, yet remains experimentally challenging. It is demonstrated here that independent sets of RDCs can be measured for ubiquitin using just a single alignment medium composed of aligned bacteriophage Pf1 particles embedded in a...
A device for the measurement of residual chemical shift anisotropy and residual dipol
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