Several enzymes are involved in DNA repair pathways. Which one of the ...
Methyltransferase - The Suicidal Enzyme
DNA repair enzymes play a crucial role in maintaining the integrity of the genome by correcting any damage that may occur. Among these enzymes, methyltransferase stands out as a unique player in the DNA repair pathway.
Suicidal Enzyme
Methyltransferase, also known as O6-methylguanine-DNA methyltransferase (MGMT), is often referred to as a "suicidal enzyme" because of its remarkable self-sacrificing mechanism. When MGMT encounters alkylated DNA lesions, such as O6-methylguanine, it transfers the alkyl group to its own active site cysteine residue. This covalent modification inactivates the enzyme, rendering it unable to repair any further DNA damage.
Importance in DNA Repair
Although the inactivation of methyltransferase might seem counterintuitive, this unique mechanism ensures the efficient repair of alkylated DNA lesions. By sacrificing itself to remove the harmful alkyl group from the DNA, methyltransferase prevents the propagation of mutations that could lead to genomic instability and ultimately cancer.
Conclusion
In summary, methyltransferase's role as a suicidal enzyme highlights the intricate and strategic nature of DNA repair mechanisms. Despite its self-inactivation, the sacrifice made by methyltransferase is essential for maintaining genomic integrity and protecting cells from the deleterious effects of DNA damage.