Bacterial DNA gyrase (Type II topoisomerase) (DNA gyrase)

Bacterial DNA gyrase is a specialized Type II topoisomerase enzyme found exclusively in bacteria, composed of GyrA and GyrB subunits. It is unique in its ability to introduce negative supercoils into DNA using ATP hydrolysis, in addition to relaxing positive supercoils. By actively managing DNA supercoiling, DNA gyrase facilitates, and is essential for, DNA replication, transcription, and maintenance of chromosome structure. DNA gyrase is a validated and widely exploited antibacterial drug target; its inhibition leads to the accumulation of DNA breaks and bacterial cell death. Structurally and functionally, gyrase differs from eukaryotic topoisomerases, making it a selective target for antibiotics such as fluoroquinolones and coumarins.

Other names

DNA topoisomerase IIGyrase (GyrA/GyrB)Type II DNA topoisomeraseTopoisomerase II (bacterial)Gyrase AGyrase B

Drugs bind to the gyrase-DNA complex, stabilizing the DNA cleavage state and preventing religation, leading to double-strand DNA breaks and bacterial cell death (bactericidal effect). Inhibition of ATPase activity, blocking energy-dependent supercoiling.