An illustration of DNA supercoiling domains in the E. coli chromosome. This is a cartoon of the chromosome; in real life there are perhaps as many as 400 different domains. Plectonemic (unrestrained) and toroidal (restrained, for example by wrapping around a protein) supercoiling is indicated. Curved DNA tends to be localized at the tips of supercoils. The illustration is modified with permission from .
Willenbrock and Ussery Genome Biology 2004 5:252 doi:10.1186/gb-2004-5-12-252