CEM 311 Lecture Notes - Lecture 44: Dna Polymerase Iii Holoenzyme, Okazaki Fragments, Dna Replication
Document Summary
Mismatch dna repair is one of the three major dna repair pathways. It deals with mispairings which are overlooked by dna pol iii"s proof reading. Muts scans along the dsdna for distortion, following right after the replisome. If found, introduces a kink in dna to mark damage spot and recruits mutl & muth (endonuclease). Mutl activates muth to cause a nick on the strand near the site of mismatch. Then a helicase (uvrd) unwinds the nicked dna strand and an exonuclease (3"-5" exo and 5"-3" exo) progressively digests the displaced dna strand beyond the mismatch. The ssdna gap produced is then filled in by dna pol iii and closed by ligase. Defined as: the average number of nucleotides added each time dna polymerase binds to a dna primer-template complex. Refers to the speed of dna synthesis, to cope with cellular activites and cell division. For example, e. coli genome consists of 3. 000. 000 bp and replication is completed in.
