BIOL-UA 21 Lecture Notes - Lecture 12: Dna Glycosylase, Dna Ligase, Dna Polymerase
18 Mar 2016
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Document Summary
Dna damage per cell is range of 104-106 per day. Normal cellular reactions can produce hydroxyl radicals, or superoxide. Different types of damages and repairs: that can cause damage: mismatch, nick, adduct repair. Deamination of methylcytosine can lead to c-t change. Methylated cytosine spontaneously converting on its own will leading to a base pair change if not caught by repair machinery. Dna glycosylase = goes around the genome and looks for t-g mismatches and removes the base (t) Machine repair has evolved with this mistake realized that the methylated cytosine can frequently turn to a. Apei endonuclease = cleaves dna backbone on one side of the damage base, and 2 other enzymes ap lyase and dna polym. Beta removes damage out and ligate the backbone with the proper c. Incorporation of wrong base by the polymerase. Polymerase can make mistakes = 99% are fied by proofreading.
