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

ABSTRACT: Processivity clamps mediate polymerase switching for translesion synthesis (TLS). All three E. 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 makes a unique secondary contact with the clamp through non-CBM residues. However, the role of this "rim contact" in Pol IV-mediated TLS remains poorly understood. Here we show that the rim contact is critical for TLS past strong replication blocks. In in vitro reconstituted Pol IV-mediated TLS, ablating the rim contact compromises TLS past 3-methyl dA, a strong block, while barely affecting TLS past N²-furfuryl dG, a weak block. Similar observations are also made in E. coli cells bearing a singl

SUBMITTER: Chang S 

PROVIDER: S-EPMC11160790 | biostudies-literature | 2024 May

REPOSITORIES: biostudies-literature