The effect of changes in the bulk dielectric constant on the DNA torsional properties

The effect of changes in the bulk dielectric constant on the DNA torsional properties was evaluated from plasmid circularization reactions. In these reactions, pUC18 previously linearized by EcoRI digestion was recircularized with T4 DNA ligase. The bulk dielectric constant of the reaction medium wa...

Full description

Saved in:
Bibliographic Details
Published in:Biopolymers 2007-11, Vol.87 (4), p.244-248
Main Authors: de Souza, Fátima Pereira, Neto, Augusto Agostinho, Fossey, Marcelo Andrés, Neto, João Ruggiero
Format: Article
Language:English
Subjects:
Deoxyribonuclease EcoRI - chemistry
dielectric constant
DNA
DNA, Circular - chemistry
electrophoresis
helical twist angle
neutral solutes
Nucleic Acid Conformation
Plasmids - chemistry
Thermodynamics
Torsion, Mechanical
torsional energetic parameter
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The effect of changes in the bulk dielectric constant on the DNA torsional properties was evaluated from plasmid circularization reactions. In these reactions, pUC18 previously linearized by EcoRI digestion was recircularized with T4 DNA ligase. The bulk dielectric constant of the reaction medium was decreased by the addition of different concentrations of neutral solutes: ethylene glycol, glycerol, sorbitol, and sucrose, or increased by the addition of glycine. The topoisomers generated by the ligase reaction were resolved by agarose‐gel electrophoresis. The DNA twist energy parameter (κ), which is an apparent torsional constant, was determined by linearization of the Gaussian topoisomers' distribution. It was observed that the twist energy parameter for the given solutes is almost linearly dependent on the bulk dielectric constant. In the reaction buffer, the twist energy parameter was determined to be 1100 ± 100. By decreasing the dielectric constant to 74 with the addition of sorbitol, the value of the parameter reaches κ = 900 ± 100, whereas the addition of ethylene glycol leads to κ = 400 ± 50. Upon addition of glycine, which resulted in a dielectric constant equal to 91, the value of the twist energy parameter increased to κ = 1750 ± 100. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 244–248, 2007. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
ISSN:0006-3525
1097-0282
DOI:10.1002/bip.20830