Which bacterial enzymes do fluoroquinolone antibiotics inhibit?

Fluoroquinolone antibiotics specifically target bacterial enzymes known as DNA gyrase and topoisomerase IV. These enzymes play crucial roles in bacterial DNA replication, transcription, and repair.

DNA gyrase is responsible for inducing negative supercoils in bacterial DNA, which is essential for the unwinding process that occurs ahead of the replication fork during DNA replication. Inhibiting DNA gyrase disrupts the ability of bacteria to properly replicate their DNA, leading to cell death or the inability to reproduce.

Topoisomerase IV, on the other hand, is critical for decatenation, which is the process that separates two interlinked circular DNA molecules after replication. By inhibiting this enzyme, fluoroquinolones effectively prevent the successful completion of DNA replication, further impairing bacterial growth and proliferation.

These targeted actions of fluoroquinolones are a key reason for their efficacy against a wide range of bacterial infections, making the inhibition of DNA gyrase and topoisomerase IV the cornerstone of how these antibiotics operate. Other options listed involve enzymes that are either not relevant to the action of fluoroquinolones or are associated with different classes of antibiotics, which do not target bacterial DNA processes directly as fluoroquinolones do.