What can base excision repair fix?

Base excision repair (BER) corrects DNA damage from oxidation, deamination and alkylation. Such base lesions cause little distortion to the DNA helix structure.

What happens during base excision repair?

base excision repair, pathway by which cells repair damaged DNA during DNA replication. Base excision repair helps ensure that mutations are not incorporated into DNA as it is copied.

What is the end result of base excision repair?

What is the end result of base excision repair? The nucleotide bearing the incorrect base is excised and replaced with a nucleotide bearing the correct base.

What does base excision repair require?

BER requires only four or five enzymes in the basic reaction steps to carry out repair of DNA containing AP sites or base damage. These include a DNA glycosylase, an AP endonuclease, a DNA polymerase, and a DNA ligase 15. BER is initiated with excision of a damaged base by the DNA glycosylase.

Is base excision repair direct repair?

Base excision repair (BER) is a cellular mechanism, studied in the fields of biochemistry and genetics, that repairs damaged DNA throughout the cell cycle. It is responsible primarily for removing small, non-helix-distorting base lesions from the genome.

How does excision repair work?

In nucleotide excision repair, the damaged nucleotide(s) are removed along with a surrounding patch of DNA. In this process, a helicase (DNA-opening enzyme) cranks open the DNA to form a bubble, and DNA-cutting enzymes chop out the damaged part of the bubble.

Can excision repair cause mutations?

If the improper uracils or thymines in these base pairs are not removed before DNA replication, they will cause transition mutations.

What is the difference between base excision repair and mismatch repair?

In base excision repair, just the damaged base is removed. In nucleotide excision repair, as in the mismatch repair we saw above, a patch of nucleotides is removed.

Which enzyme is involved in excision repair?

Excision repair involves removal of a damaged nucleotide by dual incisions bracketing the lesion; this is accomplished by a multisubunit enzyme referred to as the excision nuclease or excinuclease.

What is a base mismatch?

Base pair mismatches that arise occasionally during replication are subsequently repaired in a process that takes advantage of the fact that newly synthesized DNA in some organisms is undermethylated. From: Encyclopedia of Genetics, 2001.

What happens if mutations are not corrected?

Mutations cause a change in the DNA sequence and then to the changes in the functional product of the gene or proteins. Mutations get established if the error occurred during replication is not repaired and the cell does not recognise them as errors and the incorrect sequence gets replicated.