HLSC 2P21 Lecture Notes - Lecture 19: Topoisomerase, Dna Ligase, Phosphodiester Bond
15 Oct 2017
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10/31/2016 5:44:00 pm: dna polymerase and the beta sliding clamp are required for processive dna synthesis, binding of a pol iii core to the beta clamp tethers the core to the dna for processive synthesis. In the illustration, two pol iii cores connect to beta clamps on the leading and lagging strands. Primase (dnag) transiently associated with dnab for the synthesis of an rna primer on the lagging strand. The lagging strand pol iii core beta clamp travels with the replisome, yet extends dna in the 5" to 3", resulting in a dna loop. The opposed directions result in formation of a dna loop for each okazaki fragment. As multiple okazaki fragments are synthesized, loops repeatedly grow and are released, similar to the movement of a trombone slide as the instrument is played. Just two rounds of chromosome replication are shown here.
