dna glycosylase

It is specialized to fix single base damage in the form of small chemical modifications.

Dna glycosylase. In dna repair and beyond. Dna glycosylase are a family of enzymes involved in the classification 3 2 2 base excision repair ec number ec. Dna glycosylase catalyzes the first step of this process. The base excision repair machinery protects dna in cells from the damaging effects of oxidation alkylation and deamination.

If unrepaired these base lesions induce mutations and cell death and contribute to aging and cancer. Base excision repair is the mechanism by which damaged bases in dna are removed and replaced. Base modifications can be mutagenic and or cytotoxic depending on how they interfere. Dna 3 methyladenine glycosylase also known as 3 alkyladenine dna glycosylase aag or n methylpurine dna glycosylase mpg is an enzyme that in humans is encoded by the mpg gene.

They remove the damaged nitrogenous base while leaving the sugar phosphate backbone intact creating an apurinic apyrimidinic site commonly referred to as an ap site. Dna glycosylase repair also known as base excision repair ber is a mechanism present in all living cells which removes lesions generated by spontaneous dna decay endogenous or exogenous genotoxic agents. Then ap endonuclease cleaves the 5 deoxyribose phosphate in the dna backbone of a single strand leaving a 3 hydroxy end and a 5 deoxyribose phosphate end second downward arrow. Alkyladenine dna glycosylase is a specific type of dna glycosylase.

Coli uracil dna glycosylase udg catalyses the release of free uracil from uracil containing dna. Udg efficiently hydrolyzes uracil from single stranded or double stranded dna but not from oligomers 6 or fewer bases. This is accomplished by flipping the damaged base out of the double. The first downward arrow shows thymine dna glycosylase tdg removing 5 formylcytosine 5fc from the dna backbone leaving an apyrimidinic site.

Uracil dna glycosylase uracil n glycosylase removes uracil residues from the sugar moiety of single and double stranded dna without destroying the phosphodiester backbone preventing its use as a hybridization target or as a template for dna polymerases. Coli strain that carries the udg gene from e. Udg will not remove uracil from rna. Thermo scientific uracil dna glycosylase udg ung catalyzes the hydrolysis of the n glycosylic bond between uracil and sugar leaving an apyrimidinic site in uracil containing single or double stranded dna see figure 1 in supporting data.