RAD3 protein of Saccharomyces cerevisiae is a DNA helicase.

P. Sung, L. Prakash, S. W. Matson, S. Prakash

Research output: Contribution to journalArticlepeer-review

200 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)8951-8955
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
StatePublished - Dec 1987
Externally publishedYes

ASJC Scopus subject areas

  • General


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