|WikiProject Genetics||(Rated C-class, High-importance)|
|WikiProject Molecular and Cell Biology||(Rated Start-class, High-importance)|
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. 184.108.40.206 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 220.127.116.11 (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 18.104.22.168 (talk) 21:45, 13 May 2008 (UTC)
Discovery section confusion
I don't understand the wording of the first sentence of this section: "The origins of this enzyme predate the discovery of the enzyme." What does that actually mean? Of course the enzyme predates its discovery--should the sentence read "The concept of a topoisomerase predates the actual discovery of this enzyme"? I didn't edit the page directly, since I'm a mathematician, not a geneticist.—Bowenthebeard (talk) 21:22, 1 June 2009 (UTC)
Substrate binding site
Does the Topoisomerase require a substrate binding site, if so what is the substrate needed for the reaction to occur? —Preceding unsigned comment added by 22.214.171.124 (talk) 15:06, 12 January 2011 (UTC)
In the section Topoisomerase#Topological_problems, on the first statement "There are three main types of topology: supercoiling, knotting, and catenation." , the hyperlink on "Catenation", bring us to this-page on Catenation in basic-level chemistry.
Though fundamentally the fundamental origin of the word "catenation" , is catena , that means chain; but in the fundamental chemistry, catenation means the property of atoms of an element to form a long-chain molecule like these:
We commonly tell as carbon shows very high catenation property, whereas chlorine shows very minute catenation etc.
It has directly nothing to do with "interlock", however in case of molecular biology, the root "catena" often means "interlock" (Such as Catenane is formed at the end of theta type replication of DNA (Circular_bacterial_chromosome#Termination)); because traditionally chain is made up with interlocking metallic objects, like this:
So this hyperlink should be change to a better-one (if there is some article about interlocked rings in topology).