DnaB and DciA: mechanisms of helicase loading and translocation on ssDNA.

ABSTRACT: Replicative helicases are assembled on chromosomes by helicase loaders before the initiation of DNA replication. Here, we investigate the mechanisms employed by the bacterial Vibrio cholerae (Vc) DnaB replicative helicase and the DciA helicase loader. Structural analysis of the ATPγS form of the VcDnaB-ssDNA complex reveals a configuration distinct from that observed with GDP•AlF4. With ATPγS, the amino-terminal domain (NTD) tier, previously found as an open spiral in the GDP•AlF4 complex, adopts a closed planar arrangement. Furthermore, the DnaB subunit at the top of the carboxy-terminal domain (CTD) spiral is displaced by approximately 25 Å between the two forms. We suggest that remodeling the NTD layer between closed planar and open spiral configurations, along with the migration of two

SUBMITTER: Gao N 

PROVIDER: S-EPMC12214026 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature