PMID: 30201718 , Related PDB ids: 6DGD, 6DCR

Authors:

Windgassen TA, Leroux M, Satyshur KA, Sandler SJ, Keck JL

Title:

Structure-specific DNA replication-fork recognition directs helicase and replication restart activities of the PriA helicase.

Journal:

Proc Natl Acad Sci U S A. 2018 Sep 10. pii: 1809842115. doi:, 10.1073/pnas.1809842115.

Abstract:

DNA replication restart, the essential process that reinitiates prematurely terminated genome replication reactions, relies on exquisitely specific recognition of abandoned DNA replication-fork structures. The PriA DNA helicase mediates this process in bacteria through mechanisms that remain poorly defined. We report the crystal structure of a PriA/replication-fork complex, which resolves leading-strand duplex DNA bound to the protein. Interaction with PriA unpairs one end of the DNA and sequesters the 3'-most nucleotide from the nascent leading strand into a conserved protein pocket. Cross-linking studies reveal a surface on the winged-helix domain of PriA that binds to parental duplex DNA. Deleting the winged-helix domain alters PriA's structure-specific DNA unwinding properties and impairs its activity in vivo. Our observations lead to a model in which coordinated parental-, leading-, and lagging-strand DNA binding provide PriA with the structural specificity needed to act on abandoned DNA replication forks.