Dielectric relaxation and orientation of DNA molecules

Hanss, M.; Bernengo, Jean‐Claude

doi:10.1002/bip.1973.360120918

Cited by 57 publications

(25 citation statements)

References 23 publications

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“…In studies of the relaxation of DNA in saline solutions, Takashima observed an a relaxation at around 100 Hz [1,16], for DNA molecular masses of 5 x 10^D . Hanss and Sakamoto [10,20,32,35,36,94] performed experiments on the same length molecules and found relaxations in the 5 to 1000 Hz range. Takashima used a capacitor with platinum-blacked electrodes to measure permittivity from 1 Hz to 1000 Hz.…”

Section: Simple Model Of Dipole Momentmentioning

confidence: 98%

“…Higher-frequency measurements were made by a number of authors [40,[89][90][91][92]. Low-frequency measurements have been made by Takashima, Sakamoto, Hanss, and Tung [16,20,32,93]. In studies of the relaxation of DNA in saline solutions, Takashima observed an a relaxation at around 100 Hz [1,16], for DNA molecular masses of 5 x 10^D .…”

Section: Simple Model Of Dipole Momentmentioning

confidence: 99%

“…[20]. In alternating fields, the symmetry of the molecule may be deformed slightly to produce a small permanent dipole moment [1].…”

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Electrical properties and dielectric relaxaction of DNA in solution

Baker–Jarvis¹

1998

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Section: Simple Model Of Dipole Momentmentioning

confidence: 98%

Section: Simple Model Of Dipole Momentmentioning

confidence: 99%

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Electrical properties and dielectric relaxaction of DNA in solution

Baker–Jarvis¹

1998

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“…Oosawa (3) examined a similar fluctuation mechanism for rigid rods and concluded that attractive forces resulted if coupling occurred between counterion distributions along neighboring rods. It is the current beliefthat fluctuations in the small-ion distribution about a polyion are also responsible for the enhancement of the dielectric constant for linear polyelectrolytes at low frequencies of the external field (4)(5)(6)(7)(8)(9). It follows, therefore, that the dynamics of polyions would be greatly affected under conditions that promote large amplitude fluctuations in the small-ion distributions.…”

mentioning

confidence: 99%

“…Dapp = 1/2TK2, [5] where K = (4lTn/A)sin(0/2) is the scattering vector, n is the index of refraction, A = 488 nm, and 0 is the scattering angle. Fig.…”

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Effect of titration charge on the diffusion of bovine serum albumin.

Schmitz¹,

Lü²

1983

Proc. Natl. Acad. Sci. U.S.A.

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Quasi-elastic light scattering studies were performed on purified bovine serum albumin sample under conditions of high and low ionic strength and pH. Two relaxation modes were observed in all cases. The apparent diffusion coefficient obtained in the asymptotic time window (T) limit T-* 0-i.e., Dapp(T --* 0)-was found to be 6.1 X 10-7 cm2/sec under conditions that minimized electrical forces (100 mM KCI at pH 4.5). As the ionic strength was lowered to 0.1 mM KCI (pH 4.5) or the pH was raised to 10 (100 mM KCI), Dapp(T -*0) increased to 7.2-7.5 X 10-7 cm2/sec. Kirkwood and Shumaker first suggested that fluctuations in the net charge of proteins can fully account for the observed permanent dipole of globular proteins (1) and that these fluctuations may lead to substantial attractive interactions between the polyions (2). Oosawa (3) examined a similar fluctuation mechanism for rigid rods and concluded that attractive forces resulted if coupling occurred between counterion distributions along neighboring rods. It is the current beliefthat fluctuations in the small-ion distribution about a polyion are also responsible for the enhancement of the dielectric constant for linear polyelectrolytes at low frequencies of the external field (4-9). It follows, therefore, that the dynamics of polyions would be greatly affected under conditions that promote large amplitude fluctuations in the small-ion distributions. Lin et aL (10) examined the effect of coupled polyion-small-ion dynamics on the apparent diffusion coefficient, with the result Dapp = (I/2)[Dp(l -fl) + Ds (1 + fl)], [1] where DP is the polyion diffusion coefficient, Ds is the small ion diffusion coefficient, and [4] where the first term is the hydrodynamic dissipation term for a Stokes bead of radius ap, and the second term is referred to as the electrolyte dissipation term, which arises from an asymmetric distribution of small ions about the polyion. The parameters in Eq. 4 are: solvent viscosity (ii), electrolyte dissipation charge (Zedc), electron charge (e), small-ion diffusion coefficient (Dj), Debye-Huckel screening parameter (K), and bulk dielectric constant (E). It has been suggested through use of Eq. 4 that "apparent unfolding" of polyelectrolytes as the ionic strength is lowered below 50 mM actually may be overestimated because of the presence of significant electrolyte dissipation effects (12). We have proposed that small-ion fluctuations play a significant role not only in the self-diffusion coefficient of polyions but also in the stabilization of "localized ordered domains" within the polyelectrolyte solution (13-18). The involvement of small ions was suggested to explain quasi-elastic light-scattering (QLS) experiments performed in the presence of a sinusoidal electric field (QLS-SEF). The apparent electrophoretic mobility and apparent diffusion coefficient for mono-and polynucleosomes showed a dispersion curve in the same frequency range as that of the dielectric constant for low molecular weight DNA. The increased amplitude of the slow...

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Electro-optic studies of polymers of varying flexibility in solution

Nwammuo¹,

Maitland

1999

Angew. Makromol. Chem.

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By use of rectangular and reversing pulse electric birefringence techniques, the electrical properties of polymers of intermediate degrees of flexibility were studied. The effects of chain flexibility, interactions, temperature and solvent on the electrical properties of seven selected polymers are covered. In all the cases the concentration‐field dependence is exponential. There is also considerably deviation from the Kerr law as the field is increased. The Kerr constants are measured for some systems for the first time while results for others are in good agreement with similar systems studied in the past. For fairly rigid polymers the Kerr constant variation with concentrations is of the form B ∝ Cζc where the exponent ζc is 2.0 for monodisperse poly(γ‐benzyl‐L‐glutamate) and 0.4 for polydisperse poly(n‐butyl isocyanate), respectively. For the flexible coil polymers the Kerr constants varied linearly with concentration. The other electrical properties, such as the dipole moments and the polarisability anisotropies for the systems show marked concentration and molecular weight dependence.

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Dielectric relaxation and orientation of DNA molecules

Cited by 57 publications

References 23 publications

Electrical properties and dielectric relaxaction of DNA in solution

Electrical properties and dielectric relaxaction of DNA in solution

Effect of titration charge on the diffusion of bovine serum albumin.

Electro-optic studies of polymers of varying flexibility in solution

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