Chain Conformation in Amorphous States

The rotational flexibility of the various bonds along the DNA chains makes possible the adoption of many different conformations, orientations and forms of the molecules. Some of these are crucial for interaction of the chains with their bio-environment and certain coformations seem to be preferred (Chapter 11). DNA chains undergo many types of oscillation, twisting, bending and so forth. The chains are known to interact reversibly with water molecules, metal ions, small organic molecules and proteins. 

FIGURE 10.44 Actions of topoisomerases. (a) Double helix formation, (b) Twisting of double helix, (c) Catenane formation from single helix, (d) Catenane from double helices. 

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