Abstract Main-chain 1HNâ??15N residual dipolar couplings (RDCs) ranging from approximately â??200 to 200 Hz have been measured for ubiquitin under strong alignment conditions in Pf1 phage. This represents a ten-fold increase in the degree of alignment over the typical weakly aligned samples. The measurements are made possible by extensive proton-dilution of the sample, achieved by deuteration of the protein with partial back-substitution of labile protons from 25 % H2O / 75 % D2O buffer. The spectral quality is further improved by application of deuterium decoupling. Since standard experiments using fixed-delay INEPT elements cannot accommodate a broad range of couplings, the measurements were conducted using J-resolved and J-modulated versions of the HSQC and TROSY sequences. Due to unusually large variations in dipolar couplings, the trosy (sharp) and anti-trosy (broad) signals are often found to be interchanged in the TROSY spectra. To distinguish between the two, we have relied on their respective 15N linewidths. This strategy ultimately allowed us to determine the signs of RDCs. The fitting of the measured RDC values to the crystallographic coordinates of ubiquitin yields the quality factor Q = 0.16, which confirms the perturbation-free character of the Pf1 alignment. Our results demonstrate that RDC data can be successfully acquired not only in dilute liquid crystals, but also in more concentrated ones. As a general rule, the increase in liquid crystal concentration improves the stability of alignment media and makes them more tolerant to variations in sample conditions. The technical ability to measure RDCs under moderately strong alignment conditions may open the door for development of alternative alignment media, including new types of media that mimic biologically relevant systems.
Content Type Journal Article
Category Article
Pages 1-15
DOI 10.1007/s10858-012-9651-4
Authors
Joshua M. Ward, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USA
Nikolai R. Skrynnikov, Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, USA
Independent alignment of RNA for dynamic studies using residual dipolar couplings
Independent alignment of RNA for dynamic studies using residual dipolar couplings
Abstract Molecular motion and dynamics play an essential role in the biological function of many RNAs. An important source of information on biomolecular motion can be found in residual dipolar couplings which contain dynamics information over the entire ms-ps timescale. However, these methods are not fully applicable to RNA because nucleic acid molecules tend to align in a highly collinear manner in different alignment media. As a consequence, information on dynamics that can be obtained with this method...
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07-20-2012 11:13 PM
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
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] Various strategies of using residual dipolar couplings in NMR-driven protein docking: application to Lys48-linked di-ubiquitin and validation against 15N-relaxation data.
Various strategies of using residual dipolar couplings in NMR-driven protein docking: application to Lys48-linked di-ubiquitin and validation against 15N-relaxation data.
Related Articles Various strategies of using residual dipolar couplings in NMR-driven protein docking: application to Lys48-linked di-ubiquitin and validation against 15N-relaxation data.
Proteins. 2005 Aug 15;60(3):367-81
Authors: van Dijk AD, Fushman D, Bonvin AM
When classical, Nuclear Overhauser Effect (NOE)-based approaches fail, it is possible, given high-resolution...
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12-01-2010 06:56 PM
[NMR paper] Residual dipolar couplings in NMR structure analysis.
Residual dipolar couplings in NMR structure analysis.
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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.
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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.
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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...
Very large residual dipolar couplings from deuterated ubiquitin
Linear Mode
