What Mechanisms are Involved in the Catalytic Process?
The catalytic process of MMR involves several mechanisms:
Mismatch Recognition: MutS homologs (e.g., MSH2-MSH6) scan the DNA and recognize mismatched base pairs. Recruitment and Activation: The recognition complex recruits MutL homologs (e.g., MLH1-PMS2), which act as molecular matchmakers, orchestrating subsequent steps. Excision: An endonuclease, such as MutH in prokaryotes, introduces a nick near the mismatch. In eukaryotes, the exonuclease EXO1 plays a significant role. Resynthesis and Ligation: DNA polymerase synthesizes the correct sequence using the undamaged strand as a template, and DNA ligase seals the nick, completing the repair.
