Abstract
In this paper we address the mechanics of ply formation in DNA supercoils. We extend the variable ply formulation of Coleman & Swigon to include end loads, and the derived constitutive relations of this generalized ply are shown to be in excellent agreement with experiments. We make a careful physical examination of the uniform ply in which two strands coil around one another in the form of a helix. We next address the problem of determining the link (Lk), twist (Tw) and writhe (Wr) of a closed DNA plasmid from an inspection of its electron micrograph. Previous work has made use of the topological relation, Lk = Tw + Wr, but we show how this kinematic result can be augmented by the mechanics solutions. A very precise result is achieved in a trial calculation.
Original language | English |
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Pages (from-to) | 959-985 |
Number of pages | 26 |
Journal | Proceedings of the Royal Society of Edinburgh A |
Volume | 458 |
Issue number | 2020 |
DOIs | |
Publication status | Published - Apr 2002 |
Keywords
- supercoiling of DNA
- DNA molecule
- writhing
- ply mechanics
- writhing of DNA
- electron micrograph
- rod theory
- ELASTIC STABILITY
- CROSS-SECTION
- SELF-CONTACT
- RODS
- CONFIGURATIONS
- MOLECULE
- LINKING
- NUMBER
- MODEL