5'-3' exonuclease activity

Definition

Target type: molecularfunction

Catalysis of the hydrolysis of ester linkages within nucleic acids by removing nucleotide residues from the 5' end. [GOC:ai]

5'-3' exonuclease activity is a molecular function that involves the removal of nucleotides from the 5' end of a nucleic acid strand. This activity is typically catalyzed by enzymes called exonucleases, which can be found in various cellular compartments.

The mechanism of 5'-3' exonuclease activity involves the sequential hydrolysis of phosphodiester bonds, releasing individual nucleotides from the 5' terminus. This process often requires a free 5' hydroxyl group on the DNA or RNA molecule.

5'-3' exonuclease activity plays crucial roles in various cellular processes, including:

* **DNA replication:** During DNA replication, 5'-3' exonucleases are involved in proofreading and removing incorrectly incorporated nucleotides, ensuring the fidelity of the newly synthesized DNA strand.
* **DNA repair:** 5'-3' exonucleases are essential for DNA repair pathways, such as base excision repair (BER) and nucleotide excision repair (NER), where they remove damaged or mismatched nucleotides.
* **RNA processing:** 5'-3' exonucleases are involved in the maturation of RNA transcripts, such as removing leader sequences and processing ribosomal RNA (rRNA) and transfer RNA (tRNA).
* **Recombination:** 5'-3' exonucleases contribute to homologous recombination by generating single-stranded DNA overhangs that can be used as substrates for strand invasion.

The specific functions of 5'-3' exonucleases can vary depending on the enzyme and the cellular context. However, their ability to degrade nucleic acids from the 5' end is fundamental for maintaining genomic integrity, regulating gene expression, and ensuring proper cellular function.'
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Proteins (1)

Compounds (3)