The Bloom's Syndrome Helicase Unwinds G4 DNA

BLM, the gene that is defective in Bloom's syndrome, encodes a protein homologous to RecQ subfamily helicases that functions as a 3′-5′ DNA helicase in vitro. We now report that the BLM helicase can unwind G4 DNA. The BLM G4 DNA unwinding activity is ATP-dependent and requires a short 3′ region...

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Bibliographic Details
Published in:The Journal of biological chemistry 1998-10, Vol.273 (42), p.27587-27592
Main Authors: Sun, Hui, Karow, Julia K., Hickson, Ian D., Maizels, Nancy
Format: Article
Language:English
Subjects:
Adenosine Triphosphatases - metabolism
Adenosine Triphosphate - metabolism
Bloom Syndrome
DNA - metabolism
DNA Helicases - metabolism
DNA Replication
Guanine
Humans
Models, Genetic
Nucleic Acid Conformation
Recombination, Genetic
RecQ Helicases
Substrate Specificity
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Summary:BLM, the gene that is defective in Bloom's syndrome, encodes a protein homologous to RecQ subfamily helicases that functions as a 3′-5′ DNA helicase in vitro. We now report that the BLM helicase can unwind G4 DNA. The BLM G4 DNA unwinding activity is ATP-dependent and requires a short 3′ region of single-stranded DNA. Strikingly, G4 DNA is a preferred substrate of the BLM helicase, as measured both by efficiency of unwinding and by competition. These results suggest that G4 DNA may be a natural substrate of BLM in vivo and that the failure to unwind G4 DNA may cause the genomic instability and increased frequency of sister chromatid exchange characteristic of Bloom's syndrome.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.273.42.27587