Exonuclease

Exonuclease is an enzyme that works to degrade DNA by removing nucleotide sequences from the ends. This process is crucial in various biological processes such as DNA replication, DNA repair, and recombination.

Function

Exonucleases are classified into two types based on the direction in which they degrade the DNA. The two types are 3' to 5' exonucleases and 5' to 3' exonucleases.

• 3' to 5' exonucleases remove sequences from the 3' end of the DNA. They play a significant role in the process of DNA replication and repair.

• 5' to 3' exonucleases remove sequences from the 5' end. They are involved in the process of DNA recombination and also in the repair of damaged DNA.

Role in DNA Replication

During DNA replication, exonucleases play a crucial role in proofreading the newly synthesized DNA strands. The 3' to 5' exonuclease activity of the DNA polymerase enzyme removes any incorrectly paired nucleotides from the 3' end of the new strand, ensuring the accuracy of DNA replication.

Role in DNA Repair

Exonucleases are also involved in the process of DNA repair. They help in the removal of damaged sections of DNA, allowing the repair enzymes to replace the damaged sections with the correct sequences.

Role in Recombination

5' to 3' exonucleases are involved in the process of DNA recombination. They help in the generation of single-stranded DNA that is necessary for the recombination process.

See Also

• Endonuclease
• DNA replication
• DNA repair
• Recombination

References

Exonuclease Resources
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