Final answer:
Mismatch repair enzymes recognize newly synthesized DNA without methyl groups and replace the incorrect nucleotides with the aid of the proteins Muts, MutL, and MutH. Nucleotide excision repair makes cuts around damaged bases, such as pyrimidine dimers, and also replaces them with the correct nucleotides. These repair processes maintain the integrity of DNA after replication.
Step-by-step explanation:
The process by which mismatch repair enzymes recognize a mismatch incorporation after DNA replication involves a mechanism where the newly synthesized DNA strand is identified due to the lack of methyl groups that are otherwise present on the template, or parental, DNA strand. In E. coli, the enzyme MutH distinguishes the newly synthesized strand by the absence of a methyl group on adenine. Proteins Muts and MutL assist in the repair process by binding to the mismatch and facilitating the removal of the incorrect nucleotide by MutH. An exonuclease then removes a portion of the DNA including the incorrect nucleotide. DNA polymerase III fills in the gap with the correct nucleotide, and DNA ligase seals the strand to restore the integrity of the DNA molecule.
Nucleotide excision repair is another type of repair mechanism where enzymes make cuts on both the 3' and 5' ends of a damaged base, notably in cases where UV exposure causes the formation of pyrimidine dimers. The incorrect base is excised and replaced with the correct one, a process facilitated by DNA polymerase, with the final phosphodiester linkage sealed by DNA ligase.
The subject of this question relates to the specific mechanisms employed during the repair of mismatched or damaged nucleotides in DNA.