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Elastic model of highly supercoiled DNA
Author(s) -
Tsuru Hideo,
Wadati Miki
Publication year - 1986
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360251105
Subject(s) - dna supercoil , radius , linking number , topology (electrical circuits) , chemistry , closure (psychology) , dna , physics , geometry , classical mechanics , mathematics , combinatorics , biochemistry , dna replication , computer security , computer science , economics , market economy
The equilibrium shapes of supercoiled DNA are investigated by employing an elastic model. First, a set of Euler equations is derived to determine the equilibrium shapes under ring‐closure conditions. Two exact solutions that describe circular and figure‐8 shapes are obtained. Using these and their topological properties, the configuration change from the circular to the figure‐8 form is discussed. Second, more intricate structures of supercoiling DNA are studied by a numerical analysis. Among a class of configurations, the shape that has the minimum elastic energy is explicitly determined. Poisson's ratio, the ratio of the self‐avoiding radius to the total length, and the deficit (or excess) of the linking number ΔLk are found to be the important parameters. We conclude that the topology and the elastic theory of looped DNA explain the essential features of the supercoiling phenomena.