Biochemistry 2280A Lecture Notes - Lecture 16: Dna Mismatch Repair, Pyrimidine Dimer, Ap Site
22 Sep 2020
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Document Summary
To preserve genetic information, the cell must guard against unintended changes in the sequence or structure of dna ( dna damage). , the first intermediate formed during reduction of oxygen to water by complex iv: another group of mutagens is the polycyclic aromatic hydrocarbons, strand breaks. Dna synthesis is cleaved by an endonuclease, and the resulting nick is sealed by dna ligase: nucleotide excision repair, pyrimidine dimers and base modifications that distort the helical structure of dna are repaired by nucleotide excision repair (ner) In this pathway, an endonuclease cuts the backbone of the damaged strand on either side of the site of damage: the distance b/w the nicks varies from organism-organism (in humans it"s. 29 bases: the damaged section is removed and new dna is synthesized to replace it, using the undamaged strand as a template, people with a defect in ner suffer from xeroderma pigmentosum.
