Rotational Inhibition and Magnetization Transfer in α-Crystallin Solutions

Koenig, Seymour H.; Brown, Rodney D.; Pande, Ajay; Ugolini, Raphael

doi:10.1006/jmrb.1993.1027

Cited by 8 publications

(4 citation statements)

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“…We have shown here that the apparent correlation time of 1 ,s, deduced from 2H relaxation dispersion profiles from several immobilized proteins at different temperatures (Kimmich et al, 1990;Koenig et al, 1993b;Koenig and Brown, 1993), does not reflect a universal dynamic behavior of protein-associated water molecules, as previously suggested (Koenig et al, 1993a; Brown, 1993, 1994). Using a stochastic theory of spin relaxation (B. Halle, submitted for publication), which, in contrast to the conventional perturbation theory, is valid for slowly ex-1995a, b; Denisov and Halle, in preparation), including changing quadrupolar nuclei in immobilized protein sam-ples, we have demonstrated that the apparent correlation time of 1 ,us is nothing but the inverse of the deuteron quadrupole frequency, which indeed is expected to be independent of temperature and protein structure.…”

Section: Discussionsupporting

confidence: 50%

A new view of water dynamics in immobilized proteins

Halle¹,

Денисов²

1995

Biophysical Journal

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The inflection frequency of the deuteron magnetic relaxation dispersion from water in rotationally immobilized protein samples has recently been found to be essentially independent of temperature and protein structure. This remarkable invariance has been interpreted in terms of a universal residence time of 1 microseconds for protein-associated water molecules. We demonstrate here that this interpretation is an artifact of the conventional perturbation theory of spin relaxation, which is not valid for rotationally immobile proteins. Using a newly developed non-perturbative, stochastic theory of spin relaxation, we identify the apparent correlation time of 1 microseconds with the inverse of the nuclear quadrupole frequency, thus explaining its invariance. The observed dispersion profiles are consistent with a broad distribution of residence times, spanning the microseconds range. Furthermore, we argue that the deuteron dispersion is due to buried water molecules rather than to the traditional surface hydration previously invoked, and that the contribution from rapidly exchanging protein hydrogens cannot be neglected. The conclusions of the present work are also relevant to proton relaxation in immobilized protein samples and to magnetic resonance imaging of soft tissue.

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Section: Discussionsupporting

confidence: 50%

A new view of water dynamics in immobilized proteins

Halle¹,

Денисов²

1995

Biophysical Journal

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“…Nuclear magnetic relaxation dispersion experiments showed that, under these conditions, αB-crystallin has a rotational correlation time of about 1.4 μs. 117 For αB-crystallin, the CP buildup curves and intensities for both 1 H-13 C and 13 C-15 N CP were found to be similar to those measured on precipitated protein, indicating that molecular tumbling under these conditions is extremely slow, 50 consistent with prior measurements of the nuclear magnetic relaxation dispersion profile 118 and proton relaxation in the doubly rotating frame 119 of concentrated α-crystallin solutions. Although this methodology is applicable to many large protein complexes, αB-crystallin acts as an ideal test case because of the high concentration at which it is found in its native environment.…”

Section: α-Crystallin Structure Dynamics and The Role Of The Flexibsupporting

confidence: 73%

NMR Studies of Eye Lens Crystallins

Martin

2014

eMagRes

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The crystallins of the eye lens are highly stable, soluble proteins that generate the refractive index gradient of the lens. In their native context, the crystallins form large soluble oligomers; a loss in solubility due to mutation, UV light damage, or chemical modification results in cataract. There are two broad classes of ubiquitous crystallin proteins; βγ -crystallins, which are purely structural, and the α-crystallins, which additionally play a chaperone role, maintaining solubility of compromised proteins in the lens. NMR methods have been used to investigate many structural and functional properties of both types of crystallins. Structures have been solved for many of the crystallins using both solid-state and solution NMRs, and these detailed molecular pictures have been used as a starting point for investigating conformational dynamics and intermolecular interactions.

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“…3 require that the magnetization of solute protons be in magnetic contact with the majority ofprotein NH protons. Whether this is dominated by direct contact through chemical diffusion of solvent or magnetization transfer at the protein-solvent interface and spin diffusion within the protein is an unsettled issue at present, although there is increasing evidence that magnetization transfer dominates (48,49).…”

Section: N Peaks Of #L-crystallin and Other Crystallinsmentioning

confidence: 99%

“…This explains the onset of intermolecular interactions at a protein concentration as low as one-half the weight-fraction expected, independent of the extent of oligomerization (if any) of solute. The mechanisms underlying the mobile-immobile (i.e., solid-state like) "transition" in crystallins, as exhibited in NMRD profiles, has only recently been clarified (30,35,49), and involves changes in the details of nuclear relaxation and transport when Brownian rotation is slower than that of a 50,000 kD sphere (see reference 29). (Indications of both liquidand solid-state behavior at high concentrations have been reported in off-resonance and cross-polarization high resolution NMR measurements, respectively, of bovine lens homogenates (52).…”

Section: An Overview Of Crystallinsmentioning

confidence: 99%

Intermolecular protein interactions in solutions of bovine lens beta L-crystallin. Results from 1/T1 nuclear magnetic relaxation dispersion profiles

Koenig¹,

Brown²,

Kenworthy³

et al. 1993

Biophysical Journal

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We report the magnetic field dependence of 1/T1 of solvent water protons and deuterons (nuclear magnetic relaxation dispersion, or NMRD, profiles) for solutions of steer lens beta L-crystallin. Such data allow the study of intermolecular protein interactions over a wide concentration range, here 1-34% vol/vol, by providing a measure of the rotational relaxation time of solute macromolecules. We conclude that, for approximately less than 5% protein, the solute particles are noncompact, with a rotationally averaged volume approximately three times that of a compact 60-kD sphere. (Earlier results for alpha-crystallin, approximately 1,000 kD, from optical and osmotic measurements (Vérétout and Tardieu, 1989. J. Mol. Biol. 205:713-728), show a similar, approximately twofold, effect). At intermediate concentrations, to approximately 20% protein, there is evidence for limited association or oligomerization, as found for the structurally related gamma II-crystallin (Koenig et al. 1990. Biophys. J. 57:461-469), to a limiting size about two-thirds that of alpha-crystallin. The difference in NMRD behavior of the three classes of crystallins is consonant with their differing osmotic properties (Vérétout and Tardieu. J. Mol. Biol. 1989, 205:713-728; Kenworthy, McIntosh, and Magid. Biophys. J. 1992. 61:A477; Tardieu et al. 1992. Eur. Biophys. J. 21:1-12). We indicate how the unusual structures and interactions of these three classes of proteins can be combined to optimize transparency and minimize colloid osmotic difficulties in eye lens.

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Rotational Inhibition and Magnetization Transfer in α-Crystallin Solutions

Cited by 8 publications

References 0 publications

A new view of water dynamics in immobilized proteins

A new view of water dynamics in immobilized proteins

NMR Studies of Eye Lens Crystallins

Intermolecular protein interactions in solutions of bovine lens beta L-crystallin. Results from 1/T1 nuclear magnetic relaxation dispersion profiles

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