RAD3 protein of Saccharomyces cerevisiae is a DNA helicase.
The Saccharomyces cerevisiae RAD3 gene, which is required for cell viability and excision repair of damaged DNA, encodes an 89-kDa protein that has a single-stranded DNA-dependent ATPase activity. We now show that the RAD3 protein also possesses a helicase activity that unwinds duplex regions in DNA substrates constructed by annealing DNA fragments of 71-851 nucleotides to circular, single-stranded M13 DNA. The DNA helicase activity is dependent on the hydrolysis of ATP, has a pH optimum of approximately 5.6, and is inhibited by antibodies raised against a truncated RAD3 protein produced in Escherichia coli. The RAD3 helicase translocates along single-stranded DNA in the 5'----3' direction. The direction of RAD3 helicase movement is consistent with the possibility that it unwinds DNA duplexes in advance of the replication fork during DNA replication.
Sung
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Department of Biology, University of Rochester, NY 14627.
Prakash
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Matson
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SW
Prakash
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D000937:Antigen-Antibody Reactions; D004265:DNA Helicases / Q000302:isolation & purification / Q000502:physiology*; D004260:DNA Repair; D004261:DNA Replication; D005656:Fungal Proteins / Q000302:isolation & purification / Q000502:physiology*; D012441:Saccharomyces cerevisiae / Q000502:physiology*
D005656:Fungal Proteins; D004265:DNA Helicases