Volume 50, Number 4, May II 2000
|Page(s)||559 - 564|
|Section||Interdisciplinary physics and related areas of science and technology|
|Published online||01 September 2002|
Crystalline toroidal globules of DNA and other semi-flexible polymers: Jumps in radius caused by hexagonal packing
Institute of Advanced Studies,
Research School of Physical Sciences and Engineering
The Australian National University - Canberra, ACT 0200, Australia
School of Chemistry, University of Sydney - Sydney, NSW 2006, Australia
Accepted: 21 March 2000
We study a single semiflexible polymer chain immersed in a poor solvent. Such chains are stiff and are known to form toroidal globules. Here we examine the effects of hexagonally ordered packing of the chains. This packing induces a series of sharp transitions in the circuit number (number of complete circuits of the toroid) and major radius of the torus as a function of chain length. Circuit numbers corresponding to closed shells are strongly favoured and circuit numbers corresponding to a spare loop are forbidden. The potential landscape as a function of the circuit number consists of a series of minima separated by barriers. In some cases these barriers may be high enough to produce long-lived non-equilibrium tori.
PACS: 87.15.-v – Biomolecules: structure and physical properties / 36.20.Ey – Conformation (statistics and dynamics) / 05.60.-k – Transport processes
© EDP Sciences, 2000
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