Base Excision Repair is another repair pathway that our cells go through when there's a damage in the DNA.
Base Excision Repair in short terms is just removing the wrong base and replacing it with the right one.
Different enzymes are alerted in almost each step:
1. Wrong base in the sequence = DNA glycocylase removes that wrong base only and leaving behind a phosphate site without a base (a.k.a. an AP site or Abasic Phosphate Site)
2. Appearance of an AP site = alerts and is recognized by an enzyme called an AP endonuclease which will make a cut/cleave the phosphodiester bond found in the phosphate backbone of the AP site.
3. A cleaved phospate backbone = gets recognized by an lyase which will now remove a stretch of DNA randomly.
4. Missing stretch of DNA = allows DNA polymerase to come in and add at the free 3'OH of one of the strands and elongate it with the tight sequence.
5. A gap between the 3' and 5 ' end = fixed by ligase by connecting it and catalyzing a phosphodiester bond between the two
6. Repaired DNA = yay!
