DNA catabolic process

Definition

Target type: biologicalprocess

The cellular DNA metabolic process resulting in the breakdown of DNA, deoxyribonucleic acid, one of the two main types of nucleic acid, consisting of a long unbranched macromolecule formed from one or two strands of linked deoxyribonucleotides, the 3'-phosphate group of each constituent deoxyribonucleotide being joined in 3',5'-phosphodiester linkage to the 5'-hydroxyl group of the deoxyribose moiety of the next one. [GOC:go_curators, ISBN:0198506732]

DNA catabolic processes are the enzymatic breakdown of DNA into smaller units. This process is essential for various cellular functions, including DNA repair, replication, and recombination. It involves a series of steps, each catalyzed by specific enzymes:

1. **Depurination:** This step removes purine bases (adenine and guanine) from DNA, leaving an abasic site. The enzyme responsible for this is called DNA glycosylase.
2. **Depyrimidination:** This step removes pyrimidine bases (cytosine and thymine) from DNA, also leaving an abasic site. The enzyme responsible for this is called DNA glycosylase.
3. **Nicking:** This step breaks the phosphodiester backbone of DNA at the abasic site. The enzyme responsible for this is called an AP endonuclease.
4. **Excision:** This step removes the damaged or abasic nucleotides from the DNA strand. The enzyme responsible for this is called a 5'-3' exonuclease.
5. **Gap Filling:** This step fills the gap created by the excision of the damaged nucleotides. The enzyme responsible for this is called DNA polymerase.
6. **Ligation:** This step joins the newly synthesized DNA segment to the rest of the DNA strand. The enzyme responsible for this is called DNA ligase.

These steps can be repeated multiple times to completely degrade DNA into its constituent nucleotides. These nucleotides can then be recycled for use in other cellular processes, such as DNA replication and repair.

DNA catabolic processes also play a critical role in defense mechanisms against pathogens. For example, many bacteria and viruses have mechanisms to degrade host DNA, preventing the host from using it for their own purposes. These processes also ensure that the host genome does not become overloaded with damaged DNA.

Overall, DNA catabolic processes are essential for maintaining the integrity of the genome and for supporting various cellular processes. They are tightly regulated and controlled by specific enzymes and pathways, ensuring that DNA is broken down only when necessary and in a controlled manner.'
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Proteins (4)

Compounds (24)