Skip to main content
Article
Helicase-binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
Faculty of Science - Papers (Archive)
  • Charikleia Ioannou, University of Nottingham
  • Patrick M Schaeffer, Australian National University
  • Nicholas E Dixon, University of Wollongong
  • Panos Soultanas, University of Nottingham
RIS ID
16849
Publication Date
1-1-2006
Publication Details

Ioannou, C., Schaeffer, P. M., Dixon, N. E. & Soultanas, P. (2006). Helicase-binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis. Nucleic Acids Research, 34 (18), 5247-5258.

Abstract
The Bacillus subtilis DnaI, DnaB and DnaD proteins load the replicative ring helicase DnaC onto DNA during priming of DNA replication. Here we show that DnaI consists of a C-terminal domain (Cd) with ATPase and DNA-binding activities and an N-terminal domain (Nd) that interacts with the replicative ring helicase. A Zn21-binding module mediates the interaction with the helicase and C67, C70 and H84 are involved in the coordination of the Zn21. DnaI binds ATP and exhibits ATPase activity that is not stimulated by ssDNA, because the DNAbinding site on Cd is masked by Nd. The ATPase activity resides on the Cd domain and when detached from the Nd domain, it becomes sensitive to stimulation by ssDNA because its cryptic DNAbinding site is exposed. Therefore, Nd acts as a molecular ‘switch’ regulating access to the ssDNA binding site on Cd, in response to binding of the helicase. DnaI is sufficient to load the replicative helicase from a complex with six DnaI molecules, so there is no requirement for a dual helicase loader system.
Citation Information
Charikleia Ioannou, Patrick M Schaeffer, Nicholas E Dixon and Panos Soultanas. "Helicase-binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis" (2006) p. 5247 - 5258
Available at: http://works.bepress.com/nick_dixon/45/