A functional interaction between the putative primosomal protein DnaI and the main replicative DNA helicase DnaB in Bacillus.
In Gram negative Escherichia coli there are two well-characterised primosomal assembly processes, the PriA- and DnaA-mediated cascades. The presence of PriA and DnaA proteins in Gram positive Bacillus spp. supports the assumption that both the PriA- and DnaA-mediated primosomal assembly cascades also operate in these organisms. However, the lack of sequence homology between the rest of the primosomal proteins indicates significant differences between these two bacterial species. Central to the process of primosomal assembly is the loading of the main hexameric replicative helicase (DnaB in E.coli and DnaC in Bacillus subtilis) on the DNA. This loading is achieved by specialised proteins known as 'helicase loaders'. In E.coli DnaT and DnaC are responsible for loading DnaB onto the DNA during primosome assembly, in the PriA- and DnaA-mediated cascades, respectively. In Bacillus the identity of the helicase loader is still not established unequivocally. In this paper we provide evidence for a functional interaction between the primosomal protein DnaI from B.subtilis and the main hexameric replicative helicase DnaB from Bacillus stearothermophilus. Our results are consistent with the putative role of DnaI as the 'helicase loader' in the Gram positive Bacillus spp.
Soultanas
P
P
School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, UK. panos.soultanas@nottingham.ac.uk
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001665:Binding Sites; D004265:DNA Helicases / Q000737:chemistry / Q000502:physiology*; D019915:DNA Primase / Q000378:metabolism; D004261:DNA Replication; D053488:DnaB Helicases; D029968:Escherichia coli Proteins / Q000235:genetics; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; C071702:DnaC protein, E coli; C448302:DnaI protein, Bacillus subtilis; D029968:Escherichia coli Proteins; D046911:Macromolecular Substances; D019915:DNA Primase; D000251:Adenosine Triphosphatases; D004265:DNA Helicases; D053488:DnaB Helicases