* Endonucleases: These enzymes cut the damaged DNA strand at specific points flanking the damaged base. There are two main types:

* 5' endonucleases: Cut the phosphodiester bond on the 5' side of the damaged base.

* 3' endonucleases: Cut the phosphodiester bond on the 3' side of the damaged base.

* Exonucleases: These enzymes remove the damaged nucleotide(s) from the DNA strand, creating a gap.

* DNA polymerase: This enzyme fills in the gap with the correct nucleotides using the undamaged strand as a template.

* DNA ligase: This enzyme seals the nick in the DNA strand, rejoining the newly synthesized DNA to the original strand.

The specific endonucleases and exonucleases involved vary depending on the type of DNA damage being repaired.

Here's a breakdown of the common types of excision repair:

* Base Excision Repair (BER): This pathway primarily targets damaged or modified bases. It involves a specific DNA glycosylase enzyme to remove the damaged base, followed by an endonuclease (often AP endonuclease) to create a single-strand break.

* Nucleotide Excision Repair (NER): This pathway repairs bulky DNA lesions that distort the DNA helix, such as UV-induced pyrimidine dimers. It involves a complex of proteins that recognize the damage and excise a larger segment of DNA, including the damaged base.

Let me know if you'd like to delve deeper into any specific type of excision repair!