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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-10-26
pubmed:abstractText
Helicase loading factors are thought to transfer the hexameric ring-shaped helicases onto the replication fork during DNA replication. However, the mechanism of helicase transfer onto DNA remains unclear. In Bacillus subtilis, the protein DnaI, which belongs to the AAA+ family of ATPases, is responsible for delivering the hexameric helicase DnaC onto DNA. Here we investigated the interaction between DnaC and DnaI from Geobacillus kaustophilus HTA426 (GkDnaC and GkDnaI, respectively) and determined that GkDnaI forms a stable complex with GkDnaC with an apparent stoichiometry of GkDnaC(6)-GkDnaI(6) in the absence of ATP. Surface plasmon resonance analysis indicated that GkDnaI facilitates loading of GkDnaC onto single-stranded DNA (ssDNA) and supports complex formation with ssDNA in the presence of ATP. Additionally, the GkDnaI C-terminal AAA+ domain alone could bind ssDNA, and binding was modulated by nucleotides. We also determined the crystal structure of the C-terminal AAA+ domain of GkDnaI in complex with ADP at 2.5 A resolution. The structure not only delineates the binding of ADP in the expected Walker A and B motifs but also reveals a positively charged region that may be involved in ssDNA binding. These findings provide insight into the mechanism of replicative helicase loading onto ssDNA.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1089-8638
pubmed:author
pubmed:issnType
Electronic
pubmed:day
13
pubmed:volume
393
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1056-69
pubmed:meshHeading
pubmed-meshheading:19744498-Adenosine Triphosphatases, pubmed-meshheading:19744498-Amino Acid Sequence, pubmed-meshheading:19744498-Bacillus, pubmed-meshheading:19744498-Bacterial Proteins, pubmed-meshheading:19744498-Binding Sites, pubmed-meshheading:19744498-Chromatography, Gel, pubmed-meshheading:19744498-Crystallography, X-Ray, pubmed-meshheading:19744498-DNA, Single-Stranded, pubmed-meshheading:19744498-DNA Helicases, pubmed-meshheading:19744498-DNA Replication, pubmed-meshheading:19744498-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:19744498-Models, Molecular, pubmed-meshheading:19744498-Molecular Sequence Data, pubmed-meshheading:19744498-Nucleotides, pubmed-meshheading:19744498-Protein Binding, pubmed-meshheading:19744498-Protein Structure, Secondary, pubmed-meshheading:19744498-Protein Structure, Tertiary, pubmed-meshheading:19744498-Sequence Alignment, pubmed-meshheading:19744498-Surface Plasmon Resonance
pubmed:year
2009
pubmed:articleTitle
Molecular interplay between the replicative helicase DnaC and its loader protein DnaI from Geobacillus kaustophilus.
pubmed:affiliation
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan 115, ROC.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't