A bipartite interaction with the processivity clamp potentiates Pol IV-mediated TLS.

ABSTRACT: Processivity clamps mediate polymerase switching for translesion synthesis (TLS). All three Escherichia coli TLS polymerases interact with the β₂ processivity clamp through a conserved clamp-binding motif (CBM), which is indispensable for TLS. Notably, Pol IV also interacts weakly with the rim of the clamp through non-CBM residues. Ablating this "rim contact" in cells results in selective sensitivity to DNA-damaging agents, raising the question how the rim contact contributes to TLS. Here, we show that the rim contact is critical for TLS past a strong replication block but barely necessary for a weak blocking lesion. Within the in vitro reconstituted E. coli replisome, the rim mutation compromises Pol IV-mediated TLS past 3-deaza-methyl dA, a strong block, whereas

SUBMITTER: Chang S 

PROVIDER: S-EPMC11892629 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature