The β subunit sliding DNA clamp is responsible for unassisted mutagenic translesion replication by DNA polymerase III holoenzyme

摘要

The replication of damaged nucleotides that have escaped DNA repair leads to the formation of mutations caused by misincorporation opposite the lesion. In Escherichia coli, this process is under tight regulation of the SOS stress response and is carried out by DNA polymerase III in a process that involves also the RecA, UmuD' and UmuC proteins. We have shown that DNA polymerase III holoenzyme is able to replicate, unassisted, through a synthetic abasic site in a gapped duplex plasmid. Here, we show that DNA poly- merase III*, a subassembly of DNA polymerase III holoen- zyme lacking the β subunit, is blocked very effectively by the synthetic abasic site in the same DNA substrate.