Novobiocin's mechanism targets which enzyme?

Novobiocin's mechanism targets which enzyme?

• A. DNA Gyrase
• B. RNA Polymerase
• C. Peptidoglycan Synthesis Enzymes
• D. 50S Ribosome

Answer: (A)

Novobiocin targets DNA gyrase, the enzyme that introduces negative supercoils into bacterial DNA and relies on ATP hydrolysis to power the strand-passing step during replication. By binding the GyrB subunit and inhibiting its ATPase activity, novobiocin stops the enzyme from properly supercoiling DNA, which blocks DNA replication and halts bacterial growth. This mechanism is distinct from drugs that inhibit transcription by targeting RNA polymerase, disrupt cell wall synthesis by inhibiting peptidoglycan enzymes, or block protein synthesis by affecting the 50S ribosomal subunit. (Note: quinolones target a different subunit, GyrA, whereas novobiocin primarily affects GyrB.)

Novobiocin targets DNA gyrase, the enzyme that introduces negative supercoils into bacterial DNA and relies on ATP hydrolysis to power the strand-passing step during replication. By binding the GyrB subunit and inhibiting its ATPase activity, novobiocin stops the enzyme from properly supercoiling DNA, which blocks DNA replication and halts bacterial growth. This mechanism is distinct from drugs that inhibit transcription by targeting RNA polymerase, disrupt cell wall synthesis by inhibiting peptidoglycan enzymes, or block protein synthesis by affecting the 50S ribosomal subunit. (Note: quinolones target a different subunit, GyrA, whereas novobiocin primarily affects GyrB.)