2PNH

Escherichia coli PriB E39A variant

Summary for 2PNH

• Entry DOI: 10.2210/pdb2pnh/pdb
• Descriptor: Primosomal replication protein n (2 entities in total)
• Functional Keywords: beta barrel, ob fold, dna binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 23366.87

Authors

Lopper, M.E.,Keck, J.L. (deposition date: 2007-04-24, release date: 2007-08-07, Last modification date: 2024-11-20)

Primary citation

Lopper, M.,Boonsombat, R.,Sandler, S.J.,Keck, J.L.
A hand-off mechanism for primosome assembly in replication restart.
Mol.Cell, 26:781-793, 2007

PubMed Abstract: Collapsed DNA replication forks must be reactivated through origin-independent reloading of the replication machinery (replisome) to ensure complete duplication of cellular genomes. In E. coli, the PriA-dependent pathway is the major replication restart mechanism and requires primosome proteins PriA, PriB, and DnaT for replisome reloading. However, the molecular mechanisms that regulate origin-independent replisome loading are not fully understood. Here, we demonstrate that assembly of primosome protein complexes represents a key regulatory mechanism, as inherently weak PriA-PriB and PriB-DnaT interactions are strongly stimulated by single-stranded DNA. Furthermore, the binding site on PriB for single-stranded DNA partially overlaps the binding sites for PriA and DnaT, suggesting a dynamic primosome assembly process in which single-stranded DNA is handed off from one primosome protein to another as a repaired replication fork is reactivated. This model helps explain how origin-independent initiation of DNA replication is restricted to repaired replication forks, preventing overreplication of the genome.

PubMed: 17588514
DOI: 10.1016/j.molcel.2007.05.012

Experimental method

X-RAY DIFFRACTION (2.25 Å)