Biology And Biomedical Sciences BIOL 381 Lecture Notes - Dna Polymerase Iii Holoenzyme, Dna Polymerase I, Dna Replication
20 Dec 2018
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Document Summary
Lagging strand replication: primer placed by primase at the fork, polymerase occurs in the opposite direction of fork (by pol iii, new primers must then be placed after the fork has moved farther up the strand. This produces okazaki fragments result of discontinuous polymerization. Small gaps form between fragments, plus the primer still needs to be removed. Dna pol i fills gaps and removes rna primer with 5" to 3" exonuclease activity. Leaves a break in the sugar phosphate backbone of the dna. Creates a phosphodiester bond to seal the nick. Iii polymerization of dntp"s 5" to 3". I remove rna primer (5" to 3" exonuclease) Both proofreading activity (3" to 5" exonuclease activity) This exonuclease activity is structurally separated from the polymerization catalytic domain of polymerase. Dna pol iii on both the leading and lagging strand are linked and following the replication fork, but move in opposite directions relative to each other.
