Replication initiation in E. coli cell

In E. coli cell, replication of genome starts at the single origin oriC. OriC is an AT rich sequence, composed of  232 – 245 bp. At the beginning, initiator protein DnaA will recognize and bind to DnaA boxes of oriC which contains 9 bp repeats, to form a large protein – DNA complex. Among the DnaA boxes, 3 boxes R1, R2, R4 have highest affinity with DnaA. This complex contributes to melting of A-T rich DNA unwinding element (DUE) which consists of three 13 bp repeats. Continue Reading →