Electrostatic-Undulatory Theory of Plectonemically Supercoiled DNA
نویسندگان
چکیده
منابع مشابه
Electrostatic-undulatory theory of plectonemically supercoiled DNA.
We present an analytical calculation of the electrostatic interaction in a plectonemic supercoil within the Poisson-Boltzmann approximation. Undulations of the supercoil strands arising from thermal motion couple nonlinearly with the electrostatic interaction, giving rise to a strong enhancement of the bare interaction. In the limit of fairly tight winding, the free energy of a plectonemic supe...
متن کاملDimensions of plectonemically supercoiled DNA.
With a view to determine the configuration and regularity of plectonemically supercoiled DNA, we have measured the small angle neutron scattering from pUC18 plasmid in saline solutions. Furthermore, we have derived the mathematical expression for the single chain scattering function (form factor) of a superhelical structure, including the longitudinal and transverse interference over the plecto...
متن کاملBehavior of supercoiled DNA.
We study DNA supercoiling in a quantitative fashion by micromanipulating single linear DNA molecules with a magnetic field gradient. By anchoring one end of the DNA to multiple sites on a magnetic bead and the other end to multiple sites on a glass surface, we were able to exert torsional control on the DNA. A rotating magnetic field was used to induce rotation of the magnetic bead, and reversi...
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Supercoiling is introduced into DNAmolecules when the double helix is twisted around its own axis in three-dimensional space. Generally, DNAmolecules are negatively supercoiled inside cells, although the level of supercoiling is not equal throughout the genome and many supercoils may be constrained by bound proteins. Supercoiling increases the free energy of DNA and influences DNA metabolism by...
متن کاملStructural diversity of supercoiled DNA
By regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism. Despite its importance, however, much about supercoiled DNA (positively supercoiled DNA, in particular) remains unknown. Here we use electron cryo-tomography together with biochemical analyses to investigate structures of individual purified DNA minicircle topoisomers with defined degrees of supercoiling...
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ژورنال
عنوان ژورنال: Biophysical Journal
سال: 1999
ISSN: 0006-3495
DOI: 10.1016/s0006-3495(99)77405-9