MBB 222 Lecture Notes - Lecture 22: Ethidium Bromide, Superoxide Dismutase, Dna Glycosylase
20 Dec 2018
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Lecture 22 part 3: dna damage and repair. Flat aromatic molecules such as acridines can intercalate between adjacent base pairs in the dna double helix. Their presence can lead to the insertion or deletion of one or more base pairs. Ethidium bromide (ethbr) intercalates between bases, becoming intensely fluorescent when exposed to uv light. Ethidium bromide is commonly used to stain dna in gels. Ethidium bromide is carcinogenic and there are safety protocols in place to make sure ethidium bromide contamination doesn"t hurt researchers. Oxidative damage to dna by reactive oxygen species. The most common source of dna damage (together with the uv damage) for living cells reactive oxygen from ionizing irradiation, or as a byproduct of aerobic metabolism. Dna repair mechanisms to repair damage caused by reactive oxygen species. The human genome sustains tens of thousands of oxidative hits per day, most of which are repaired by dna glycosylases using base excision repair.
