topoisomerase i topo i dna binding enzyme. target of a number of chemotherapy drugs used against cancer.

topoisomerase topo dna binding enzyme target number chemotherapy drugs used cancer pdb1a36 winding tangled untangled unwound unknotting inhibitor scleroderma knotting type 1b irinotecan topotecan camptothecin structure peptide protein amino acid molecule polypeptide polymer atoms science scientific disease health molecular model are represented as colorcoded spheres colored blue