DNA Gyrase is:: (A) Eukaryotic DNA Topoisomerase I, (B) Prokaryotic DNA Topoisomerase III, (C) Prokaryotic DNA Topoisomerase I, (D) Prokaryotic DNA Topoisomerase II
Answer is D. Topoisomerases Relieves supercoils. Cut and reseal DNA and relieve positive supercoils. Don't use ATP. Gain energy from the cleavage of the phosphodiester bond. DNA Gyrase: Counterpa of Topoisomerase II in prokaryotes. Introduces negative supercoils (underwinding is known as negative supercoiling) and Uses ATP Topoisomerase I Topoisomerase II Makes cut on single strand Makes cut on both strands Formation of a covalent DNA-enzyme complex preserves the free energy. ATP is not needed. ATP is needed. Relaxes negative supercoils in E. coli; Both negative and positive in Eukaryotes. Relaxes both negative & positive supercoils. +ve supercoil is relieved by introducing -ve supercoils.