Self-Association of Lysozyme as Seen by Magnetic Relaxation Dispersion

Halle, Bertil

doi:10.1021/jp034527k

Cited by 36 publications

(44 citation statements)

References 73 publications

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“…For instance the NMRD experiment has been used to study the self association of proteins [29]- [31]. The theoretical description and characterization of the NMRD dispersion profile of protein solutions provides a challenging problem [23,24,28].…”

Section: Introductionmentioning

confidence: 99%

Quadrupole-enhanced proton spin relaxation for a slow reorienting spin pair: (I)–(S). A stochastic Liouville approach

Westlund

2009

Molecular Physics

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Section: Introductionmentioning

confidence: 99%

Quadrupole-enhanced proton spin relaxation for a slow reorienting spin pair: (I)–(S). A stochastic Liouville approach

Westlund

2009

Molecular Physics

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“…Lysozyme is known to aggregate at high pH values, and is proposed [19] to be dimeric at pH 9.0. Measurements at pH* 9.0 (Figure 1 b) demonstrate the sensitivity of this technique to aggregation.…”

mentioning

confidence: 99%

NMR Spectroscopic Detection of Protein Protons and Longitudinal Relaxation Rates between 0.01 and 50 MHz

et al. 2005

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Nuclear magnetic relaxation data of water nuclei at variable fields provide valuable information on the dynamics of watersolute interactions. [1][2][3] However, information can be collected only within certain field ranges in which the nuclear relaxation rates are field-dependent owing to the dispersion of the spectral density, J(w,t). The dispersion depends on the type of motion and on the observed nucleus. The most informative 1 H NMR spectroscopic frequency range for rotational motions is centered around 10 MHz for small proteins (M W % 10 4 Da) and smaller frequencies for larger proteins and protein aggregates. Of course, resolution is low at these fields and in practice only one signal (or an unresolved signal envelope) can be detected. Furthermore, only the abundant water protons can be conveniently studied under such low sensitivity.Relaxation of the isotopes 17 O and 2 H in enriched water can also be studied; [1] in these cases the centers of the informative field ranges increase by a factor % 7 with respect to 1 H as a result of the magnetogyric ratios of 17 O and 2 H. Because water interacts with proteins, such relaxation studies provide direct information on the nature of water-protein dynamics, but give only indirect information on the protein itself.[4-6] It would be highly desirable to have complementary information directly from the protons of the protein, but this has been impractical so far owing to the low sensitivity of the available instrumentation. Protein 1 H relaxation data have been reported only on protein solutions of concentrations ! 35 % by mass, [7,8] far from physiological conditions. Improvements in field-cycling technology [9][10][11][12] have led to the production of instrumentation [13] with a % 10-fold increase in the signal-to-noise ratio, [14] with which direct protein 1 H detection can be attempted for protein concen- Figure 1. Protein 1 H relaxation dispersions for lysozyme solutions (2.8 mm in D 2 O) at a) pH* 3.5, and b) pH* 9.0 (pH=pH-meter reading in D20 solution). The time decay of the collective protein 1 H magnetization at 0.1 MHz and its single-exponential fit are shown in the inset of part a). Theoretical relaxation rates were obtained through singleexponential fits of time decays of collective protein 1 H magnetization calculated from the known protein structure of lysozyme [17] and a complete relaxation matrix (CORMA) analysis.[18] Only exchangeable NH protons from secondary structure elements ( % 50 % of total) were included, whereas all other exchangeable proton positions were assumed to be deuterated. Inclusion of either all or none of the NH protons affected the calculated rates by AE 2 %. The theoretical lowfield hE 2 i values obtained in this way were used to fit Equation (1) to the data (solid lines). The dotted lines represent data fits with two J-(w,t) terms in Equation (1) ( Table 1). Panel c) shows the protein 1 H relaxation dispersion for a solution of a-synuclein in D 2 O (1.4 mm, pH* 7.1). The solid and dotted lines represent fits with one or two J-(...

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“…Protons of one of the five water molecules buried in the HEWL molecule have been identified 30 as exchangeable with the bulk water proton pool on a time scale slow relative to the protein tumbling motion, but fast enough to affect the water proton T 1 . We include these protons in f l .…”

Section: Proton T 1 In D-hewlmentioning

confidence: 99%

“…25,31 For each protein the MRD results were consistent with a small number of slowly exchanging water molecules associated with the protein molecule. 25,30 The influence of protein aggregation on MRD profiles also has been exploited recently to study self-association of hen-egg-white lysozyme (HEWL) in solution. 30 To further characterize the spin relaxation in these systems we have studied the temperature dependence of the proton spin-lattice relaxation times T 1 in natural and deuterated HEWL solutions.…”

Section: Introductionmentioning

confidence: 99%

“…25,30 The influence of protein aggregation on MRD profiles also has been exploited recently to study self-association of hen-egg-white lysozyme (HEWL) in solution. 30 To further characterize the spin relaxation in these systems we have studied the temperature dependence of the proton spin-lattice relaxation times T 1 in natural and deuterated HEWL solutions. Through application of the exchange cross-relaxation model, 14 the importance of the labile proton-nonlabile proton coupling step in the protein-water proton magnetization exchange is estimated.…”

Section: Introductionmentioning

confidence: 99%

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Cross‐relaxation bottleneck in water–lysozyme proton magnetization exchange

Kakule¹,

Sharp²,

Schreiner³

et al. 2006

Biopolymers

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The proton spin-lattice relaxation parameters in natural and deuterated lysozyme solutions have been measured as a function of temperature (0-50 degrees C). The variation of the apparent magnitudes of the water proton magnetizations in the solutions with temperature indicates that magnetic coupling mixes protein and water proton magnetizations. The results are consistent with an exchange cross-relaxation model (Hills, B. P., Mol Phys 1992, 76, 489-508) in which the cross-relaxation acts between the labile and nonlabile protons, rather than between water and protein protons. Although this cross-relaxation pathway clearly affects the observed magnetization fractions in this protein solution, its influence on the relaxation rates is less apparent.

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Self-Association of Lysozyme as Seen by Magnetic Relaxation Dispersion

Cited by 36 publications

References 73 publications

Quadrupole-enhanced proton spin relaxation for a slow reorienting spin pair: (I)–(S). A stochastic Liouville approach

Quadrupole-enhanced proton spin relaxation for a slow reorienting spin pair: (I)–(S). A stochastic Liouville approach

NMR Spectroscopic Detection of Protein Protons and Longitudinal Relaxation Rates between 0.01 and 50 MHz

Cross‐relaxation bottleneck in water–lysozyme proton magnetization exchange

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