DNA Gyrase (Topoisomerase II) (DNA Gyrase)

DNA gyrase is a unique and essential bacterial enzyme classified as a type II topoisomerase. It catalyzes the ATP-dependent introduction of negative supercoils into double-stranded, closed-circular DNA, which is critical for maintaining DNA topology during processes such as replication, transcription, and recombination. Unlike other topoisomerases, DNA gyrase is the only known enzyme capable of actively introducing negative supercoils into DNA. It is a heterotetramer composed of two GyrA and two GyrB subunits (A₂B₂). The GyrA subunit contains the active site tyrosine responsible for cleaving and rejoining the DNA strands, while the GyrB subunit harbors the ATP-binding and hydrolysis sites necessary for energy transduction during catalysis. DNA gyrase is an established antibacterial drug target, with many antibiotics, including fluoroquinolones, acting by inhibiting its activity.

Other names

Topoisomerase IIGyrase

Inhibition of DNA gyrase activity, stabilization of cleavage complexes leading to DNA double-strand breaks