supercoiled DNA


supercoiled DNA

a conformation of a circular DNA molecule or a linear molecule, in which the ends of the DNA strands are not free to rotate, whereby the double helix is further twisted into a more compact structure. This puts extra tension into the molecule. Certain ENZYMES, such as topoisomerases and gyrases, can alter the amount of supercoiling of the DNA. The EXPRESSION of some GENES is influenced by the extent of supercoiling of the molecule