DNA Topoisomerase: types and use
In this article we will discuss about the DNA Topoisomerase:- Types of Topoisomerase & Uses of Topoisomerase.
Linking number is an invariant property of DNA i.e topologicaly constraients. It can only the change by introducing interception into the sugar phosphate backbone. A remarkable class of enzymes know as Topoisomerase are able to do this work by introducing translate single stranded or double stranded break into the DNA.
Topoisomerase are so named as there association with the Topological feature of DNA.
Types of Topoisomerase:-
Topoisomerase are of the following 2general types:-
2. Type-II Topoisomerase
Type-I Topoisomerase change the linking no. Of DNA in steps of 1.They make transite single stranded break in the DNA. Allowing the uncut releasing the Nick. In contrast to the type- II Topoisomerase type -I Topoisomerase do not require ATP.
Type-ll Topoisomerase change the linking no.in step of two. They make translate double stranded break. In the DNA before releasing the Breaks.
Type-ll Topoisomerase required the energy of ATP Hydrolysis for their action.
Both prokaryotes & eukaryotes have type-I and type-ll. Topoisomerase that have capable of removing super coil from DNA. However prokaryotes have a special type-ll. Topoisomerase know as DNA gyrase that introduced rather then removes -ve super coiled DNA gyrase is responsible for the -ve super coiled of DNA in prokaryotes.
Uses of Topoisomerase:-
Topoisomerase use a covalent protein DNA linkage to cleave and rejoint DNA stranded. DNA cleavage occurred. When a tyrosine residue in active site of Topoisomerase attacks a phosphodiester
bond in a back bones of target. DNA which general a break & Topoisomerase is covalently joined to one end of the broken end via a phosphotyrosin linkage. The other end of the DNA by the enzymes.