dna can have mutations that cause a base in the dna strand to be damaged. to ensure genetic integrity of the dna, enzymes need to repair any damage. there are many types of dna repair. base excision repair utilizes base flipping to flip the damaged base out of the double helix and into the specificity pocket of a glycosylase which hydrolyzes the glycosidic bond and removes the base. dna glycosylases interact with dna, flipping bases to determine a mismatch. an example of base excision repair occurs when a cytosine base is deaminated and becomes a uracil base. this causes a u:g mispair which is detected by uracil dna glycosylase. the uracil base is flipped out into the glycosylase active pocket where it is removed from the dna strand. base flipping is used to repair mutations such as 8-oxoguanine (oxog) and thymine dimers created by uv radiation.