Reanalysis of histone‐induced conformational changes in DNA determined by quasielastic light scattering

Ramsay-Shaw, Barbara; Schmitz, Kenneth S.

doi:10.1002/bip.1976.360151121

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…The solid lines are the theoretical predictions obtained by solving eq 4-8. a function of added multivalent ion concentration for Mg2+ (from Rhee and Ware27), Sp3+, and Sp4+, together with the theoretical dependences obtained by solving eq 4-8 (b = 1.7 A, ¿ = 4.2, Vp = 646 cm3/mol P, l/ = 62.6 A). For N = 2 the data lie above the theoretical line, for TV = 3 the data lie first above the line and then below at concentrations above ~40 µ , and for TV = 4 the experimental dependence appears to cross the theoretical line around 7 µ . Rhee and Ware27 attributed the deviation for Mg2+ to be a consequence of the fact that cN in the Manning theory is the free TV-valent ion concentration.…”

Section: Discussionmentioning

confidence: 72%

Condensation of Polyamines onto Nucleic Acids

Wei¹,

Rhee²,

Ware³

1983

J. Phys. Chem.

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Section: Discussionmentioning

confidence: 72%

Condensation of Polyamines onto Nucleic Acids

Wei¹,

Rhee²,

Ware³

1983

J. Phys. Chem.

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“…In contrast to the other models, analysis of the friction factor of the dimer unit required the presence of a bridge region in the low-ionic-strength solvent. 31,32 Although the helical supramolecular conformation of nucleosomes is strongly favored, there is no general agreement as to the parametric representation of this structure. This is due, in part, to the large number of parameters needed to describe the structure and the interrelationship of these parameters.…”

Section: Introductionmentioning

confidence: 98%

Chromatin conformation: A systematic analysis of helical parameters from hydrodynamic data

Schmitz

Ramsay-Shaw

1977

Biopolymers

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SynopsisChromatin has a "bead-and-bridge" appearance when viewed by electron microscopy. We have used quasielastic light scattering and sedimentation velocity techniques to study the hydrodynamic properties of chicken erythrocyte chromatin multimers in an attempt to determine the superstructure in solution. The functional dependence of the friction factor on the number of core particles in the multimer was analyzed by the Garcia de la Torre-Bloomfield formalism for a rigid array of odd-sized beads. The hydrodynamic parameters of the monomeric and dimeric subunit components, i.e., bead size and separation, form the basis of a systematic determination of the superstructure. These calculations support a helical conformation for chromatin multimers containing up to twenty repeat units. It is also shown that an "equivalent" helix can be obtained if the bead separation distance is not constrained to that determined for the dimer.

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Dynamic light‐scattering studies of internal motions in DNA. I. Applicability of the rouse‐zimm model

Lin¹,

Schurr²

1978

Biopolymers

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SynopsisThe intermediate scattering function G ( K , t ) for any polymer model obeying a linear separable Langevin equation can be expressed in terms of the eigenvalues and eigenvectors of its normal coordinate transformation. An algorithm for the exact numerical evaluation of G ( K , t ) for linear Rouse-Zimm chains in the presence of hydrodynamic interaction has been developed. The computed G ( K , t ) 2 were fit to C ( t ) = A exp(-t/TA) + B, and apparent diffusion coefficients calculated according to Dapp = 1/(27,4K2). G(K,t)2 was surprisingly well-fit by single-exponential decays, especially a t both small and large values of Kb, where K is the scattering vector and b the root-mean-squared subunit extension. Plots of D,,, vs K 2 invariably showed a sigmoidal rise from Do a t K 2 = 0 up to a constant plateau value a t large K2b2.Analytical expressions for G(K,t), exact in the limit of short times, were obtained for circularRouse-Zimm chains with and without hydrodynamic interaction, and also for free-draining linear chains, and in addition for the independent-segment-mean-force (ISMF) model. The predicted behavior for G(K,t) a t large Kb (or KRc) was found in all cases to be single-exponential with ~/ T A a K 2 a t large Kb, in agreement with the computational results. A simple procedure for estimating all parameters of the Rouse-Zimm model from a plot of Dapp vs K 2 is proposed. Experimental data for both native and pH-denatured calf-thymus DNA in 1.OM NaCl with and without EDTA clearly exhibit plateau behavior of D,,, a t large values of K , in harmony with the present Rouse-Zimm and ISMF theories, and in sharp contrast to previous predictions based on the Rouse-Zimm model.

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Reanalysis of histone‐induced conformational changes in DNA determined by quasielastic light scattering

Cited by 5 publications

References 13 publications

Condensation of Polyamines onto Nucleic Acids

Condensation of Polyamines onto Nucleic Acids

Chromatin conformation: A systematic analysis of helical parameters from hydrodynamic data

Dynamic light‐scattering studies of internal motions in DNA. I. Applicability of the rouse‐zimm model

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