DNA polymerase II (also known as DNA Pol II or Pol II) is a prokaryotic DNA polymerase most likely involved in DNA repair.
The enzyme is 90 kDa in size and is coded by the polB gene. DNA Pol II can synthesize DNA new base pairs at an average rate of between 40 and 50 nucleotides/second. Strains lacking the gene show no defect in growth or replication. Synthesis of Pol II is induced during the stationary phase of cell growth. This is a phase in which little growth and DNA synthesis occurs. It is also a phase in which the DNA can accumulate damage such as short gaps, which act as a block to DNA Pol III. Under these circumstances, Pol II helps to overcome the problem because it can reinitiate DNA synthesis downstream of gaps. Pol II has a low error rate but it is much too slow to be of any use in normal DNA synthesis. Pol II differs from Pol I in that it lacks a 5'->3' exonuclease activity, and cannot use a nicked duplex template.
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