{"doi":"10.1016/j.jbc.2024.107275","title":"Biochemical characterization of Escherichia coli DnaC variants that alter DnaB helicase loading onto DNA","abstract":"DNA replication in E. coli starts with loading of the replicative helicase, DnaB, onto DNA . This reaction requires the DnaC loader protein, which forms a 6:6 complex with DnaB and opens a channel in the DnaB hexamer through which single-stranded DNA is thought to pass. During replication, replisomes frequently encounter DNA damage and nucleoprotein complexes that can lead to replication fork collapse. Such events require DnaB re-loading onto DNA to allow replication to continue. Replication restart proteins mediate this process by recruiting DnaB 6 /DnaC 6 to abandoned DNA replication forks. Several dnaC mutations that bypass the requirement for replication restart proteins or that block replication restart have been identified in E. coli . To better understand how these DnaC variants function, we have purified and characterized the protein products of several such alleles. Unlike wild-type DnaC, three of the variants (DnaC 809, DnaC 809,820, and DnaC 811) can load DnaB onto replication forks bound by single-stranded DNA-binding protein. DnaC 809 can also load DnaB onto double-stranded DNA. These results suggest that structural changes in the variant DnaB 6 /DnaC 6 complexes expand the range of DNA substrates that can be used for DnaB loading, obviating the need for the existing replication restart pathways. The protein product of dnaC1331 , which phenocopies deletion of the priB replication restart gene, blocks loading through the major restart pathway in vitro . Overall, the results of our study highlight the utility of bacterial DnaC variants as tools for probing the regulatory mechanisms that govern replicative helicase loading.","journal":"Journal of Biological Chemistry","year":2024,"id":453530,"datarank":0.3865336368476192,"base_score":2.1972245773362196,"endowment":2.1972245773362196,"self_citation_contribution":0.32958368660043297,"citation_network_contribution":0.05694995024718625,"self_endowment_contribution":0.32958368660043297,"citer_contribution":0.05694995024718625,"corpus_percentile":null,"corpus_rank":null,"citation_count":8,"citer_count":8,"citers_with_citation_signal":3,"citers_with_endowment":3,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.955,"is_data_producer":true,"deposit_databanks":{"Dryad":["10.5061/dryad.qrfj6q5pg"]},"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2024-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":475676,"name":"James L. Keck","orcid":"0000-0002-5961-0220","position":1,"is_corresponding":false},{"id":453606,"name":"Sarah D. McMillan","orcid":"0009-0005-8378-5177","position":0,"is_corresponding":true}],"reference_count":39,"raw_metadata":null,"created_at":"2026-07-19T02:03:03.428151Z","pmid":"38588814","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}