In: Biology
List and explain the functions of three different enzymes that participate in DNA replication.
How does DNA polymerase work to proofread a DNA strand?
Primase- DNA polymerase starts the DNA replication by its own. It needs 3'-OH to add nucleotide. So Primase adds few bases in the newly synthesized DNA and then DNA polymerase continues the replication. Primase adds short RNA on the Leading and lagging strand.
DNA topoisomerase- It is the first enzyme which binds to the DNA origin of replication. Its main function is to unwind by breaking the H-bond between the nitrogen bases.
RNase-H - During DNA replication, RNA primer is formed. It needed to be removed so that DNA replication is completed. RNase-H removed the RNA from the hybrid so the new nucleotide can be added to the primary site.
DNA replication always occurs in 5' to 3' direction. If by mistake any wrong nucleotide is added then it needs to be replaced by the correct nucleotides. To carry out the removal of wrong nucleotide DNA polymerase has 3' to 5' exonuclease activity. This exonuclease activity helps in the removal of the wrong nucleotide .