title: Spo0J regulates the oligomeric state of Soj to trigger its switch from an activator to an inhibitor of DNA replication initiation.
abstract: Control of DNA replication initiation is essential for bacterial cells to co-ordinate the faithful replication and segregation of their genetic material. The Bacillus subtilis ATPase Soj is a dynamic protein that regulates DNA replication initiation by either inhibiting or activating the DNA replication initiator protein DnaA. Here we report that the key event which switches Soj regulatory activity is a transition in its oligomeric state from a monomer to an ATP-dependent homodimer capable of DNA binding. We show that the DNA binding activity of the Soj dimer is required both for activation of DNA replication initiation and for interaction with Spo0J. Finally, we demonstrate that Spo0J inhibits Soj dimerization by stimulating Soj ATPase activity. The data provide a molecular explanation for the dichotomous regulatory activities of Soj, as well as assigning unique Soj conformations to distinct cellular localization patterns. We discuss how the regulation of Soj ATPase activity by Spo0J could be utilized to control the initiation of DNA replication during the cell cycle.
authors.affiliation: Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle Upon Tyne NE2 4AX, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Scholefield
authors.forename: Rachel
authors.initials: R
authors.lastname: Whiting
authors.forename: Jeff
authors.initials: J
authors.lastname: Errington
authors.forename: Heath
authors.initials: H
authors.lastname: Murray
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D001412:Bacillus subtilis / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D055503:Protein Multimerization; D013171:Spores, Bacterial / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C066312:DnaA protein, Bacteria; C030069:spore-specific proteins, Bacillus; D000251:Adenosine Triphosphatases