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  • 1
    Electronic Resource
    Electronic Resource
    An NMR investigation of the changes in plasma membrane triglyceride and phospholipid precursors during the activation of T-lymphocytes (1992)
    s.l. : American Chemical Society
    Biochemistry 31 (1992), S. 9098-9106 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00152a054
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Measuring protein self-association using pulsed-field-gradient NMR spectroscopy: Application to myosin light chain 2 (1995)
    Springer
    Journal of biomolecular NMR 6 (1995), S. 321-328 
    Details
    ISSN: 1573-5001
    Keywords: Pulsed-field-gradient NMR ; Translational diffusion coefficient ; Self-association ; Myosin light chain ; CHAPS
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary At the millimolar concentrations required for structural studies, NMR spectra of the calcium-binding protein myosin light chain 2 (MLC2) showed resonance line widths indicative of extensive self-association. Pulsed-field-gradient (PFG) NMR spectroscopy was used to examine whether MLC2 aggregation could be prevented by the zwitterionic bile salt derivative 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). PFG NMR measurements indicated that CHAPS was capable of preventing MLC2 self-association, but only at concentrations well above the critical micelle concentration of ∼7.5 mM. CHAPS was most effective at a concentration of 22.5 mM, where the apparent molecular mass of MLC2 correponded to a protein monomer plus seven molecules of bound detergent. The resolution and sensitivity of 2D 15N-1H HSQC spectra of MLC2 were markedly improved by the addition of 25 mM CHAPS, consistent with a reduction in aggregation following addition of the detergent. The average amide nitrogen T2 value for MLC2 increased from ∼30 ms in the absence of CHAPS to ∼56 ms in the presence of 25 mM CHAPS. The results of this study lead us to propose that PFG NMR spectroscopy can be used as a facile alternative to conventional techniques such as analytical ultracentrifugation for examining the self-association of biological macromolecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00197813
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  • 3
    Electronic Resource
    Electronic Resource
    Determination of backbone nitrogen–nitrogen J correlations in proteins (1997)
    Springer
    Journal of biomolecular NMR 10 (1997), S. 403-408 
    Details
    ISSN: 1573-5001
    Keywords: Nitrogen–nitrogen J coupling ; HOHAHA ; TOCSY ; ψ Angle ; Relaxation ; Ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Recently, a quantitative J correlation technique has been presented which makes use of homonuclear Hartmann–Hahn cross-polarization (TOCSY) to measure 3JC′C′ in proteins isotopically enriched with 13C [Grzesiek, S. and Bax, A. (1997) J. Biomol. NMR, 9, 207–211]. Since homonuclear Hartmann–Hahn is twice as fast as conventional COSY transfer, this method is much less sensitive to transverse relaxation, which is the principal limiting factor in achieving long-range J-coupling correlations in macromolecules. Here we describe a similar experiment which is used to measure3 JNN coupling constants between sequential amide15 N nuclei in the backbone of ubiquitin. As expected from the low magnetic moment of 15N, the 3JNN coupling constants are exceedingly small, with values between 0.14 and 0.36 Hz for residues in β-conformations and values below 0.15 Hz for residues in α-conformations. In contrast to what is expected from a Karplus-type dependence on the backbone angle ψ, large differences in the values of3 JNN are observed for a number of residues with very similar backbone ψ angles. A quantitative description of statistical and systematic errors, in particular of relaxation effects during the TOCSY transfer, shows that these differences are highly significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018373601391
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  • 4
    Electronic Resource
    Electronic Resource
    Characterization of the hydrogen bond network in guanosine quartets by internucleotide 3hJNC′ and 2hJNN scalar couplings (2000)
    Springer
    Journal of biomolecular NMR 16 (2000), S. 279-289 
    Details
    ISSN: 1573-5001
    Keywords: base pairs ; DNA ; hydrogen bond ; nucleic acid ; quadruplex ; scalar coupling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Scalar coupling correlations across hydrogen bonds with carbonyl groups as acceptors have been observed in a variety of proteins, but not in nucleic acids. Here we present a pulse scheme that allows such an observation and quantification of trans-hydrogen bond 3hJNC′ correlations in nucleic acid base pairs, between the imino nitrogen 15N1 and the carbonyl 13C6 nuclei within the guanine quartets of the Oxy-1.5 DNA-quadruplex. Intra- and internucleotide N-H···O=C connectivities can be traced around each guanine quartet, allowing the hydrogen bonding partners to be unambiguously assigned. Absolute values of the 3hJNC′ couplings are approximately 0.2 Hz as quantified by a selective long-range H(N)CO experiment and are thus on average smaller than the analogous 3hJNC′ couplings observed in proteins. In addition, an improved version of the pseudo-heteronuclear H(N)N-COSY [Majumdar et al. (1999) J. Biomol. NMR, 14, 67–70] is presented which allows simultaneous detection of the 15N-donor and 15N-acceptor resonances connected by 2hJNN couplings in hydrogen bonds involving amino groups. Using this experiment, values ranging between 6 and 8 Hz are determined for the 2hJNN couplings between 15N2 and 15N7 nuclei in the guanine quartet. These values are not strongly influenced by the presence of a significant amount of chemical exchange broadening due to amino group rotations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008307115641
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  • 5
    Electronic Resource
    Electronic Resource
    A doublet-separated sensitivity-enhanced HSQC for the determination of scalar and dipolar one-bond J-couplings (1999)
    Springer
    Journal of biomolecular NMR 13 (1999), S. 175-180 
    Details
    ISSN: 1573-5001
    Keywords: dipolar coupling ; hepatitis C protease ; one-bond J coupling ; sensitivity enhancement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A simple, sensitivity-enhanced HSQC experiment is described which separates the upfield and downfield components in the indirect dimension into different subspectra. The sequence is similar to the generalized TROSY scheme; however, decoupling of the X-nucleus is used during detection. A detailed analysis of relaxation effects, precision and sensitivity of the method is presented. The approach is demonstrated in a two-dimensional water flip-back 1H- 15N HSQC which measures 1JHN splittings in isotropic and oriented samples of ubiquitin and the hepatitis C protease. The results are in excellent agreement with splittings obtained from a conventional 1H-coupled HSQC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008301415843
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  • 6
    Electronic Resource
    Electronic Resource
    Measuring macromolecular diffusion using heteronuclear multiple-quantum pulsed-field-gradient NMR (1997)
    Springer
    Journal of biomolecular NMR 10 (1997), S. 1-8 
    Details
    ISSN: 1573-5001
    Keywords: Pulsed-field-gradient NMR ; Translational diffusion coefficient ; Self-association ; Macromolecules ; Solvent suppression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We have previously shown that 1H pulsed-field-gradient(PFG) NMR spectroscopy provides a facile method for monitoring proteinself-association and can be used, albeit with some caveats, to measure theapparent molecular mass of the diffusant [Dingley et al. (1995) J. Biomol.NMR, 6, 321–328]. In this paper we show that, for15N-labelled proteins, selection of1H-15N multiple-quantum (MQ) coherences in PFGdiffusion experiments provides several advantages over monitoring1H single-quantum (SQ) magnetization. First, the use of agradient-selected MQ filter provides a convenient means of suppressingresonances from both the solvent and unlabelled solutes. Second,1H-15N zero-quantum coherence dephases morerapidly than 1H SQ coherence under the influence of a PFG.This allows the diffusion coefficients of larger proteins to be measuredmore readily. Alternatively, the gradient length and/or the diffusion delaymay be decreased, thereby reducing signal losses from relaxation. In orderto extend the size of macromolecules to which these experiments can beapplied, we have developed a new MQ PFG diffusion experiment in which themagnetization is stored as longitudinal two-spin order for most of thediffusion period, thus minimizing sensitivity losses due to transverserelaxation and J-coupling evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018339526108
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