Biopolymers and cell. 1986. Volume 2. № 6. 283 - 292
Yu. S. Lazurkin
DNA: SUPERCOILING AND ALTERNATIVE STRUCTURES
Summary
The effect of superhelicity of DNA on its structure and properties is reviewed. The superhelicity is shown to induce in the DNA double helix three alternative structures: cruciform, the Z form and the H form (a novel structure formed in homopurine-homopyrimidine tracts). Convincing evidence of these structures in vitro is obtained in recent years by the method of two-dimensional gel electrophoresis. Their occurrence in vivo is closely related to specific proteins which stabilize them. These proteins are believed to play an important role in regulation of the gene activity.