DnaG interacts with a linker region that joins the N- and C-domains of DnaB and induces the formation of 3-fold symmetric rings

Thirlway, Jenny; Turner, Ian J.; Gibson, Christopher T.; Gardiner, Laurence; Brady, Kevin; Allen, Stephanie; Roberts, Clive J.; Soultanas, Panos

Abstract

Loading of the replicative ring helicase onto the origin of replication (oriC) is the final outcome of a well coordinated series of events that collectively constitute a primosomal cascade. Once the ring helicase is loaded, it recruits the primase and signals the switch to the polymerization mode. The transient nature of the helicase-primase (DnaB-DnaG) interaction in the Escherichia coli system has hindered our efforts to elucidate its structure and function. Taking advantage of the stable DnaB-DnaG complex in Bacillus stearothermophilus, we have reviewed conflicting mutagenic data from other bacterial systems and shown that DnaG interacts with the flexible linker that connects the N- and C-terminal domains of DnaB. Furthermore, atomic force microscopy (AFM) imaging experiments show that binding of the primase to the helicase induces predominantly a 3-fold symmetric morphology to the hexameric ring. Overall, three DnaG molecules appear to interact with the hexameric ring helicase but a small number of complexes with two and even one DnaG molecule bound to DnaB were also detected. The structural/functional significance of these data is discussed and a speculative structural model for this complex is suggested.

Citation

Thirlway, J., Turner, I. J., Gibson, C. T., Gardiner, L., Brady, K., Allen, S., …Soultanas, P. (2004). DnaG interacts with a linker region that joins the N- and C-domains of DnaB and induces the formation of 3-fold symmetric rings. Nucleic Acids Research, 32(10),

• Journal Article Type: Article
• Publication Date: Jun 1, 2004
• Deposit Date: Aug 11, 2009
• Publicly Available Date: Aug 11, 2009
• Journal: Nucleic Acids Research
• Print ISSN: 0305-1048
• Electronic ISSN: 0305-1048
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 32
• Issue: 10
• Public URL: https://nottingham-repository.worktribe.com/output/703170
• Publisher URL: http://nar.oxfordjournals.org/cgi/content/full/32/10/2977