Journal ArticleDOI
Threshold effects observed in conformation changes induced by electric fields.
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TLDR
In this paper, it was demonstrated that the single-strand helix-coil transition in poly(A, poly(dA), and poly(C) can be induced by application of high electric fields.Abstract:
Single-stranded polynucleotides are used as model systems for the investigation of conformational changes induced by electric fields. It is demonstrated that the single-strand helix–coil transition in poly(A), poly(dA), and poly(C) can be induced by application of high electric fields. The transition is measured by UV absorbance using polarized light at an angle of 54.8° with respect to the vector of the electric field and by electrodichroism. A linear increase of the absorbance, reflecting the helix-to-coil transition, is observed at increasing field strength. When ions are added to the polymer, electric fields do not induce conformation changes, unless a threshold value of the electric field strength E0 is exceeded. At field strengths above this threshold, the degree of transition is a linear function of the increase in field strength. The threshold values E0 show a linear increase with the logarithm of the ion concentration. Bivalent ions cause thresholds at much lower ion concentrations than mo-novalent ions. The shielding efficiency of ions is correlated to the binding affinity of these ions to the polymer.
The conformation changes induced by the field and the existence of thresholds can be explained on the basis of dissociation field effects. Similar threshold effects may be expected for other macromolecules as well as for membrane structures and may be important in the regulation of bioelectricity.read more
Citations
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Journal ArticleDOI
The molecular theory of polyelectrolyte solutions with applications to the electrostatic properties of polynucleotides.
TL;DR: An analogous situation existed in the field of protein chemistry during the period after the formulation and confirmation of the Debye—Huckel theory of ionic solutions but before Scatchard's incorporation of the theory into his analysis of the binding properties of proteins.
Journal ArticleDOI
Chemical electric field effects in biological macromolecules
TL;DR: Reactions in Polar Media and Polyionic Macromolecules: Permanent and Induced Dipole Moments in Polyionics.
Journal ArticleDOI
Polynucleotide conformation from flow dichroism studies.
TL;DR: It is demonstrated that the isotropic absorption and linear dichroism in an unknown flow field can be used to determine base tilt in polynucleotides if three transitions are measured and the directions of the corresponding dipoles are known.
Journal ArticleDOI
A field-dissociation relation for polyelectrolytes with an application to field-induced conformational changes of polynucleotides
TL;DR: The threshold effect found experimentally by Pörschke, and particularly the observed linear dependence of the threshold field on the logarithm of the ionic strength, appears here as a simple consequence of the linear increase of the stabilization free energy with the logarym of Ionic strength.
Journal ArticleDOI
Dual effect of high electric field in capillary electrophoresis study of the conformational stability of Bungarus fasciatus acetylcholinesterase
TL;DR: It is shown that increasing the applied field causes denaturation-like transition of the enzyme at a current power which does not induce excessive Joule heating in the capillary.
References
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Journal ArticleDOI
Conformation changes in rRNA induced by electric impulses
Arnold Revzin,Eberhard Neumann +1 more
TL;DR: The fast part of the relaxation spectrum is attributed to alignment of double-helical segments of rRNA with the external electric field; the slower part is shown to be due to changes in orientation of the entire τRNA molecule, concomitant with electric field-induced helix-coil transitions of oligomeric base-paired regions.
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Structural Transition Produced by Electric Fields in Aqueous Sodium Deoxyribonucleate
TL;DR: It was found that the birefringence of aqueous solutions of sodium DNA is anomalous when electric fields of high intensity (>/=10(4) v/cm) are applied), and it is proposed that the electric field may cause aggregation of the macromolecules and then produce a structural transition concomitant with theElectric field orientation effect.
Journal ArticleDOI
A Specific Photoreaction in Polydeoxyadenylic Acid
TL;DR: A relatively high probability of DNA photolesions, that cannot be repaired by simple repair enzyme systems, is demonstrated, indicating a high structure specificity in poly(dA).
Journal ArticleDOI
Electric birefringence of poly-L-lysine hydrobromide in methanol–water mixtures and helix–coil transition induced by high electric fields
Kazuo Kikuchi,Koshiro Yoshioka +1 more
TL;DR: The electric birefringence of poly‐L‐lysine hydrobromide in methanol–water mixtures has been measured at 25 °C over a wide range of field strengths by use of the rectangular pulse technique, and the specific Kerr constant increased rapidly with dilution in the random coil form, and more slowly in the helical conformation.
Journal ArticleDOI
A conformation change of single stranded polyriboadenyiate induced by an electric field
TL;DR: Absorbance measurements performed with high molecular weight poly A at pH 8 show that the degree of single strand stacking present at high ionic strength is reduced at low ionic strengths, suggesting that the conformation change is caused by a dissociation field effect.