Related ArticlesControlling residual dipolar couplings in high-resolution NMR of proteins by strain induced alignment in a gel.
J Biomol NMR. 2001 Oct;21(2):141-51
Authors: Ishii Y, Markus MA, Tycko R
Water-soluble biological macromolecules can be weakly aligned by dissolution in a strained, hydrated gel such as cross-linked polyacrylamide, an effect termed 'strain-induced alignment in a gel' (SAG). SAG induces nonzero nuclear magnetic dipole-dipole couplings that can be measured in high-resolution NMR spectra and used as structural constraints. The dependence of experimental 15N-1H dipolar couplings extracted from two-dimensional heteronuclear single quantum coherence (HSQC) spectra on several properties of compressed polyacrylamide, including the extent of compression, the polyacrylamide concentration, and the cross-link density, is reported for the B1 immunoglobulin binding domain of streptococcal protein G (protein G/B1, 57 residues). It is shown that the magnitude of macromolecular alignment can be widely varied by adjusting these properties, although the orientation and asymmetry of the alignment tensor are not affected significantly. The dependence of the 15N relaxation times T1 and T2 of protein G/B1 on polyacrylamide concentration are also reported. In addition, the results of 15N relaxation and HSQC experiments on the RNA binding domain of prokaryotic protein S4 from Bacillus stearothermophilus (S4 delta41, residues 43-200) in a compressed polyacrylamide gel are presented. These results demonstrate the applicability of SAG to proteins of higher molecular weight and greater complexity. A modified in-phase/anti-phase (IPAP) HSQC technique is described that suppresses natural-abundance 15N background signals from amide groups in polyacrylamide, resulting in cleaner HSQC spectra in SAG experiments. The mechanism of protein alignment in strained polyacrylamide gels is contrasted with that in liquid crystalline media.
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
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
Residual dipolar couplings: are multiple independent alignments always possible?
Residual dipolar couplings: are multiple independent alignments always possible?
Abstract RDCs for the 14 kDa protein hen egg-white lysozyme (HEWL) have been measured in eight different alignment media. The elongated shape and strongly positively charged surface of HEWL appear to limit the protein to four main alignment orientations. Furthermore, low levels of alignment and the proteinâ??s interaction with some alignment media increases the experimental error. Together with heterogeneity across the alignment media arising from constraints on temperature, pH and ionic strength for some...
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12-26-2010 04:43 AM
[NMR paper] Residual dipolar couplings in NMR structure analysis.
Residual dipolar couplings in NMR structure analysis.
Related Articles Residual dipolar couplings in NMR structure analysis.
Annu Rev Biophys Biomol Struct. 2004;33:387-413
Authors: Lipsitz RS, Tjandra N
Residual dipolar couplings (RDCs) have recently emerged as a new tool in nuclear magnetic resonance (NMR) with which to study macromolecular structure and function in a solution environment. RDCs are complementary to the more conventional use of NOEs to provide structural information. While NOEs are local-distance restraints, RDCs provide...
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11-24-2010 09:25 PM
[NMR paper] Residual dipolar couplings: synergy between NMR and structural genomics.
Residual dipolar couplings: synergy between NMR and structural genomics.
Related Articles Residual dipolar couplings: synergy between NMR and structural genomics.
J Biomol NMR. 2002 Jan;22(1):1-8
Authors: Al-Hashimi HM, Patel DJ
Structural genomics is on a quest for the structure and function of a significant fraction of gene products. Current efforts are focusing on structure determination of single-domain proteins, which can readily be targeted by X-ray crystallography, NMR spectroscopy and computational homology modeling. However,...
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11-24-2010 08:49 PM
[NMR paper] Protein structural motif recognition via NMR residual dipolar couplings.
Protein structural motif recognition via NMR residual dipolar couplings.
Related Articles Protein structural motif recognition via NMR residual dipolar couplings.
J Am Chem Soc. 2001 Feb 14;123(6):1222-9
Authors: Andrec M, Du P, Levy RM
NMR residual dipolar couplings have great potential to provide rapid structural information for proteins in the solution state. This information even at low resolution may be used to advantage in proteomics projects that seek to annotate large numbers of gene products for entire genomes. In this paper, we...
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11-19-2010 08:32 PM
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
Theoretical framework for NMR residual dipolar couplings in unfolded proteins
Theoretical framework for NMR residual dipolar couplings in unfolded proteins
O. I. Obolensky, Kai Schlepckow, Harald Schwalbe and A. V. Solov’yov
Journal of Biomolecular NMR; 2007; 39(1) pp 1-16
Abstract:
A theoretical framework for the prediction of nuclear magnetic resonance (NMR) residual dipolar couplings (RDCs) in unfolded proteins under weakly aligning conditions is presented. The unfolded polypeptide chain is modeled as a random flight chain while the alignment medium is represented by a set of regularly arranged obstacles. For the case of bicelles oriented perpendicular to...