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Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis

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...

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Detalles Bibliográficos
Autores principales: Ioannou, Charikleia, Schaeffer, Patrick M., Dixon, Nicholas E., Soultanas, Panos
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2006
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1636449/
https://www.ncbi.nlm.nih.gov/pubmed/17003052
http://dx.doi.org/10.1093/nar/gkl690
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author Ioannou, Charikleia
Schaeffer, Patrick M.
Dixon, Nicholas E.
Soultanas, Panos
author_facet Ioannou, Charikleia
Schaeffer, Patrick M.
Dixon, Nicholas E.
Soultanas, Panos
author_sort Ioannou, Charikleia
collection PubMed
description 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 Zn(2+)-binding module mediates the interaction with the helicase and C67, C70 and H84 are involved in the coordination of the Zn(2+). DnaI binds ATP and exhibits ATPase activity that is not stimulated by ssDNA, because the DNA-binding 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 DNA-binding 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.
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spelling pubmed-16364492006-11-29 Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis Ioannou, Charikleia Schaeffer, Patrick M. Dixon, Nicholas E. Soultanas, Panos Nucleic Acids Res Molecular Biology 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 Zn(2+)-binding module mediates the interaction with the helicase and C67, C70 and H84 are involved in the coordination of the Zn(2+). DnaI binds ATP and exhibits ATPase activity that is not stimulated by ssDNA, because the DNA-binding 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 DNA-binding 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. Oxford University Press 2006-10 2006-09-26 /pmc/articles/PMC1636449/ /pubmed/17003052 http://dx.doi.org/10.1093/nar/gkl690 Text en © 2006 The Author(s)
spellingShingle Molecular Biology
Ioannou, Charikleia
Schaeffer, Patrick M.
Dixon, Nicholas E.
Soultanas, Panos
Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
title Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
title_full Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
title_fullStr Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
title_full_unstemmed Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
title_short Helicase binding to DnaI exposes a cryptic DNA-binding site during helicase loading in Bacillus subtilis
title_sort helicase binding to dnai exposes a cryptic dna-binding site during helicase loading in bacillus subtilis
topic Molecular Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1636449/
https://www.ncbi.nlm.nih.gov/pubmed/17003052
http://dx.doi.org/10.1093/nar/gkl690
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