Talk:Topoisomerase

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[edit] Specific Topoisomerases

Consider adding a list of specific topoisomerases with the type they are: E.g. DNA gyrase - Type II. -Rage italic 17:02, 5 March 2007 (UTC)

[edit] Aren't Ligases responsible for reconnecting cut DNA parts?!

I have a Biology textbook right in front of me, that claims that Ligases are responsible for reconnecting the DNA parts that Topoisomerases split. As this book has turned out to be on the right side for the most part, I would consider rewriting that part. 84.185.233.56 22:25, 12 November 2007 (UTC)

In general, ligase is responsible for reconnecting breaks in DNA, but this is not always the case. With Topoisomerase I, this enzyme covalently attaches to a DNA phosphate to create a temporary break in the phosphodiester linkage of one strand of a double helix, allowing the other strand to rotate. Because the energy of the original phosphodiester bond is stored in the phosphotyrosine linkage between Topoisomerase I and the cut DNA strand, this reaction is reversible, and the strand can spontaneously reanneal without the aid of ligase. —Preceding unsigned comment added by 128.192.229.228 (talk) 01:13, 2 April 2008 (UTC)

That is true for type IA, type IIA, and type IIB topoisomerases. They all ligate DNA without the presence of a ligase. —Preceding unsigned comment added by 169.229.195.33 (talk) 21:45, 13 May 2008 (UTC)