DNA TOPOISOMERASE | Online Biotech Notes
DNA TOPOISOMERASE
Every cell has enzyme with the sole function of under winding and / or relaxing DNA The enzyme that increase or decrease the extent of DNA under winding are topoisomerase DNA topoisomerase remove the super coaling in the DNA.
Types of Topoisomerase
There are two classes topoisomerase.
- · Type I topoisomerase
- · Type II topoisomerase
Type I topoisomerase
Type I topoisomerase act by transiently breaking one of the two DNA Strands, passing the unbroken strand through the break, and rejoining the broken ends.
Type II topoisomerase
Type II topoisomerase break both DNA strand
Step 2- In step 2 cleaving it, creating covalent 5’-p-Tyr protein –DNA Linkage.
Step 3-The enzyme switches to its open conformation and the unbroken DNA strand passes through the break in the first strand.
Step 4:-The librated 3’ hydroxyl group attacks the 5’- p-tyr protein-DNA Linkage in step 4 to relegate the cleaved DNA strand.
Mechanism of DNA Topoisomerase
Step 1- DNA binds (step 0, an active site Tyr attacks a phosphodiester bond on one DNA strand in step.Step 2- In step 2 cleaving it, creating covalent 5’-p-Tyr protein –DNA Linkage.
Step 3-The enzyme switches to its open conformation and the unbroken DNA strand passes through the break in the first strand.
Step 4:-The librated 3’ hydroxyl group attacks the 5’- p-tyr protein-DNA Linkage in step 4 to relegate the cleaved DNA strand.
0 Response to "DNA TOPOISOMERASE | Online Biotech Notes"
Post a Comment