Question

Fill in the Blank 1. DNA replication in E. coli begins at a 245 base pair sequence called • The initiation of DNA replication at this site begins with the binding of the protein, to multiple 9 base pair repeats regions. The association of these proteins generate superhelical tension which unwinds the 13 bp repeat region called the . The next step of initiation involves the loading of the protein (a helicase) onto the 13 bp repeat region by another ATPase called The primosome which consist of the protein in addition to the helicase is required for synthesis. The initial primers are extended by DNA , which has a high processivity due to the subunit. This subunit is loaded and unloaded from the lagging strand by a complex called . (20 points) 2. Shown below is a replication bubble with two replisomes moving left to right and right to left. In the boxes place A or B for the leading and lagging templates for the replisome moving in the left to right direction, respectively. Labels C and D should be for the leading and lagging templates for the replisome moving in the right to left direction. Lastly, identify the protein that would stabilize the single stranded bubble.(10 points) ผิว Left to Right to left right ผิว

Answer 1

Question 1:

DNA replication in E. coli begins at a 245bp sequence called as origin of replication (oriC). The initiation of DNA replication at this site begins with the binding of the DnaA protein to multiple 9 base pair repeat regions. The association of these proteins generate superhelical tension which unwinds the 13 bp repeat region called the 13-mer. The next step of initiation involves the loading of the DnaB protein (a helicase) on to 13 bp repeat region by another ATPase called DnaC. The primosome which consists of the primase protein in addition to helicase is required for RNA primer synthesis. The initial primers are extended by DNA polymerase III, which has a high processivity due to the beta (β) subunit. This subunit is loaded and unloaded from lagging strand by a complex called γ( gamma) complex.