Topological properties of DNA
Topological properties of DNA
- Topology is the branch of mathematics which deals with structural properties of DNA that remain unchanged by structural deformities such as twisting or bending
- Covalently closed circular DNA molecules show topological property called Linking Number that determines the Degree of Supercoiling (overfolding ) of DNA.
- In 1963, J Vinograd for the first time showed presence of Supercoiling in the DNA of Polyoma virus that separated in two distinct band after centrifugation.
- Supercoiling is a phenomenon by which a duplex DNA molecule is twisted or coiled in space around its own axis. A supercoiled DNA molecule is more compact than a relaxed DNA molecule of the same length.
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Electron Micrographs of Circular DNA from Mitochondria (Supercoiled form and relaxed form) and different levels of supercoiling.
