BIOL 4246 Chapter : 6 28 12 DNA Repair
Document Summary
If you have an n glycosylase that can recognize the damaged base, you can cleave the bond and leave an ap site. Dealing with ap site is the same process throughout. Need ap endonuclease, ligase, dna pol i every time. Methyl-directed mismatch repair system in e coli: mmr- mismatch repair. All cells have them. if proofreading fails and you have unpaired bases, you have to be able to resolve that: most cells use strand breaks to direct the system. These are most common on the discontinuously synthesized strand by okazaki fragments. Immediately after dna replication, you need to be able to determine the newly synthesized strand from the template strand. Dna is hemimethylated- old strand is methylated and new strand is not: muthls- h is dna breaking activity in e. coli. In other cells l has a dna breaking domain. Cell must be going down for good before they use this system.
