Definition of Dna Gyrase
DNA gyrase belongs to the class of topoisomerases and it helps in reducing the topological strain when the double-stranded DNA helix is getting unwound by DNA helicase. This enzyme is responsible for introducing negative supercoils in the DNA molecule and on the other hand, relaxes the positive supercoils too.
The supercoiling happens when the template strand forms a crossing by cutting the helix and makes itself pass through this. In this way, the linking number gets changed by two at every enzymatic step. This phenomenon happens in the bacterial cells in which the circular DNA is cut by the gyrase and the resulting two ends get twisted around each other in order to form supercoils. This enzyme plays its role in the process of DNA replication too by relaxing the positive supercoils.