Dynamics of mouse-liver DNA by single-clipped photon correlation

Chen, F. C.; Chu, Barbara C.F.

doi:10.1063/1.434150

Cited by 6 publications

(1 citation statement)

References 2 publications

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“…These authors reported that Dfmt ~Dslow ~3.0 X 10~7 cm2/s for ionic strengths above 0.05 M, whereas these relaxation times "split" for ionic strengths below 0.05 M. For mononucleosomal DNA in 0.005 M NaCl Fulmer et al31 reported that Dslow ~2 X 10~8 cm2/s, which is comparable to the value of Dalow reported by Chen and Chu. 30 The location and breadth of the "splitting" The decay rates for• the two modes are proportional to K2, as expected for translational diffusion. The bimodal distribution is interpreted in terms of free and hindered diffusion regimes.…”

Section: Discussionmentioning

confidence: 73%

On the electrostatic contribution to the persistence length of flexible polyelectrolytes

Schmitz¹,

Yu²

1988

Macromolecules

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Fetters, L. J., unpublished results). Thus, the parameter ( R 2 ) / M was corrected to 75 "C and Tg + 100 "C. A similar change in ( R 2 ) / M for the two above temperatures was not done for PDMB since both theory and experiment indicate that d In (R2)/dT for sterreoirregular polydienes is ca. 0, e.g., see: Mays, J. W.; Hadjichristidis, N.; Graessley, W. W.; Fetters, L. The length b can be estimated from b2 = (R2)/N where N is the number of repeat units per chain. ABSTRACT Quasi-elastic light scattering methods were used to study the dynamics of dilute solutions of high molecular weight (Mp = lo7 daltons) poly(acry1ate) for [ K C l ] a = 0.00,0.05, and 0.10 M. The correlation functions were analyzed by a third-order cumulant and an overlay histogram with exponential sampling methods of analysis. The histograms exhibited a bimodal distribution. It is argued that the fast mode evident in the histograms is associated with the pure translational diffusion process for PAA-K and that the slow mode may be associated with hindered diffusion through cages formed by neighboring polyions. The ionic strength dependence of the translational diffusion coefficient is interpreted in terms of a minor increase in both the excluded-volume parameter and the persistence length, where these parameters eventually reach a limiting value as the ionic strength is lowered. The failure of the current theoretical models of the electrostatic component to adequately describe this ionic strength dependence of the persistence length is discussed in detail.

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Section: Discussionmentioning

confidence: 73%

On the electrostatic contribution to the persistence length of flexible polyelectrolytes

Schmitz¹,

Yu²

1988

Macromolecules

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Sedimentation Coefficients, Diffusion Coefficients, Partial Specific Volumes, Frictional Ratios, and Second Virial Coefficients of Polymers in Solution

Lechner

Nordmeier

Steinmeier

1999

The Wiley Database of Polymer Properties

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Dynamic light scattering studies of internal motions in DNA. II. Clean viral DNAs

et al. 1980

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SynopsisInternal Brownian motions of clean $29 and A-DNAs have been studied using photoncorrelation techniques a t both visible (A, = 632.8 nm) and uv (A" = 363.8 nm) wavelengths. The present dynamic light scattering data, which extend to K 2 = 19 X 10' O cm-*, can in every case be satisfactorily simulated by a Rouse-Zimm model polymer with an appropriate choice of the three model parameters. The effects of pH, salt concentration, single-strand breaks, and molecular weight on those model parameters have also been investigated. Intact clean DNAs exhibit surprisingly little variation with pH from 7.85 to 10.25, with salt concentration from 0.01 NaCl to 5.4M NHIC1, or with molecular weight or GC content. The single-strand breaks have no effect a t pH 9.46, but produce dramatic changes in the model parameters at pH 10.0 and 10.25, indicating the introduction of titratable joints a t those pHs. The failure of either single-strand breaks or a large change in GC content to alter the model parameters in the neutral pH range is a strong indication that local denaturation is not required for those flexions and torsions that dominate the relaxation of fluctuations in the scattered light. The Langevin relaxation time for the slowest internal mode of a particular Rouse-Zimm model derived from the dynamic light scattering data is compared with pertinent literature data extrapolated to the same molecular weight. The present algorithm for determining model parameters from the light-scattering Dapp vs K 2 curve actually yields a Langevin time in fairly good agreement with the literature value. For unknown reasons the light-scattering Do values generally exceed those obtained from the molecular weight and sedimentation coefficient by about 20%. INTRODUCTIONThe internal Brownian motions of flexible macromolecules provide a potential means for studying their static and dynamic mechanical properties, such as flexional and torsional rigidities, structural inhomogeneities or joints, and frictional properties. For macromolecules of sufficiently great physical extent, the polarized dynamic light scattering a t high angles contains significant contributions from internal which may in some cases completely dominate the observed intensity autocorrelation functions. Unfortunately, theoretical predictions for the dynamic light scattering from very realistic models of semiflexible polymers are not yet available, so recourse must temporarily be made to oversimplified models, such as those of Rouse,6 Zimm,7 and Harris and Nevertheless, for the comparatively long wavelength fluctuations (in the distribution of polymer segments) that are actually accessible to current dynamic light Biopolymers, Vol. 19, 1451-1474 is the apparent diffusion coefficient at a given angle, T is the exponential decay time, and K is the scattering vector. Subsequent discoveryg of pronounced variations in those model parameters in the pH range 9-10 for both calf thymus DNA and an initial $29 viral DNA sample provided strong evidence for the existence of titratable joints...

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Dynamics of mouse-liver DNA by single-clipped photon correlation

Cited by 6 publications

References 2 publications

On the electrostatic contribution to the persistence length of flexible polyelectrolytes

On the electrostatic contribution to the persistence length of flexible polyelectrolytes

Sedimentation Coefficients, Diffusion Coefficients, Partial Specific Volumes, Frictional Ratios, and Second Virial Coefficients of Polymers in Solution

Dynamic light scattering studies of internal motions in DNA. II. Clean viral DNAs

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