In base-excision repair, modified bases are first excised and then the entire nucleotide is replaced. The excision of modified bases is catalyzed by a set of enzymes called DNA
MutL, MutS, MutH -(mismatch repair proteins)
^ Protein MutS binds to the mismatched bases and forms a complex with MutH and MutL; the mismatch is brought close to a methylated GATC sequence; and the new strand is identified.
Exonucleases remove nucleotides on the new strand between the GATC sequence and the mismatch.
DNA polymerase then replaces the nucleotides, correcting the mismatch, and DNA ligase seals the nick in the ^¿¡^A sugar-phosphate backbone.
Was this article helpful?