A phage-encoded inhibitor of Escherichia coli DNA replication targets the DNA polymerase clamp loader

摘要: Coliphage N4 infection leads to shut-off of host DNA replication without inhibition transcription or translation. We report the identification and characterization gp8, gene product responsible for this phenotype. gp8 is an Escherichia coli bacteriostatic inhibitor that colocalizes with E. replisome in a replication-dependent manner. Gp8 was purified observed cross-link complexes containing replicative polymerase, DNAP III, vivo. Purified inhibits polymerization by polymerase III holoenzyme vitro interfering processivity. specifically clamp-loading activity targeting delta subunit clamp loader; mutations conferring resistance were identified holA gene, encoding delta. Delta interact vitro; no interaction detected between inactive mutants wild-type gp8-resistant gp8. Therefore, work identifies loader as new target bacterial growth. Finally, we show not essential development under laboratory conditions, but its contributes phage yield.