View source for DNA topoisimerase

&nbsp;<ref>Alberts, J. L. R. W., 2008. Molecular Biology of The Cell. 5th edition ed. Ney York: Garland Science.</ref>plays an impotant role in breaking the phosophodiester bond by binding covalently onto the DNA backbone phosphate. It acst as a reversible nuclease. This whole process is a reversible one, whereby before the protein leaves, the phosophodiester bonds are re-made.&nbsp;There are two types of DNA topoisomerase, topoisomerase I and topoismerase II.<br><br> 

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Reference: 

Alberts, Bruce, 2008. Molecular Biology if The Cell. 5th ed. New York: Garland Science.