Publications by authors named "Charikleia Ioannou"

Recent work has identified a "glutamate switch" in six of the seven clades of AAA+ ATPases. The glutamate switch acts to transduce information regarding substrate binding to the ATPase active site. We provide biochemical evidence that a highly conserved threonine residue acts as a glutamate switch in the replicative helicase, MCM, and, thus, reveal that the glutamate switch is a feature common to all seven AAA+ clades.

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The helicase loader protein DnaI (the Bacillus subtilis homologue of Escherichia coli DnaC) is required to load the hexameric helicase DnaC (the B. subtilis homologue of E. coli DnaB) onto DNA at the start of replication.

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The DnaD protein is an essential component of the chromosome-replication machinery of the Gram-positive bacterium Bacillus subtilis and is part of the primosomal cascade that ultimately loads the replicative ring helicase DnaC onto DNA. Moreover, DnaD is a global regulator of DNA architecture, as it forms higher order nucleoprotein structures in order to open supercoiled DNA. Here, the crystallization and preliminary X-ray diffraction analysis of the two domains of DnaD from B.

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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 Zn2+-binding module mediates the interaction with the helicase and C67, C70 and H84 are involved in the coordination of the Zn2+.

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The Bacillus subtilis DnaD protein is an essential protein that has been implicated in the primosomal step of DNA replication, and recently in global DNA remodelling. Here we show that DnaD consists of two domains with distinct activities; an N-terminal domain (Nd) with oligomerization activity, and a C-terminal domain (Cd) with DNA-binding activity and a second DNA-induced oligomerization activity. Although Cd can bind to DNA and form large nucleoprotein complexes, it does not exhibit global DNA-remodelling activity.

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