Round 2: Tossup 14

Resistance to a class of antibiotics targeting these enzymes often disrupts a water–metal ion bridge that chelates the drug’s keto acid. One of these enzymes from the vaccinia virus modifies a 3-prime thymidine in a namesake cloning method. An inhibitor of these enzymes was isolated from the barks of Camptotheca trees, derivatives of which include irinotecan and a related drug partially named after them. These enzymes create a “gate” for the T-segment to cross in the “strand passage” mechanism. (10[2])Ciprofloxacin (-5[1])(“sip-ro-flox-uh-sin”) and other fluoroquinolones (“fluoro-quino-lones”) target these enzymes, which can resolve catenanes. Bacteria use a type of these (-5[1])enzymes called gyrase that generates negative supercoils and changes the linking number by two. (10[1]-5[1])For 10 points, name these enzymes that relieve torsional stress (10[1])in DNA. (10[1])■END■ (10[1]0[7])

Back to tossups

Buzzes

Summary