Ciprofloxacin inhibits dna gyrase, a bacterial topoisomerase that cuts dna ahead of the replication fork, winds the dna in a direction that relieves the twists added during dna synthesis, and then reseals the dna. in ciprofloxacin-treated bacteria, newly synthesized dna is found in fragments. based on this evidence, what activity of dna gyrase is likely to be inhibited by ciprofloxacin? ligase activity. dna polymerase activity. primase activity. helicase activity