Publications (2)4.96 Total impact
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Article: Sulfolobus tokodaii RadA paralog, stRadC2, is involved in DNA recombination via interaction with RadA and Hjc.
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ABSTRACT: Rad51/RadA paralogs found in eukaryotes and euryarchaea play important roles during recombination and repair, and mutations in one of the human Rad51 paralogs, Rad51C, are associated with breast and ovarian cancers. The hyperthermophilic crenarchaeon Sulfolobus tokodaii encodes four putative RadA paralogs and studies on these proteins may assist in understanding the functions of human Rad51 paralogs. Here, we report the biochemical characterization of stRadC2, a S. tokodaii RadA paralog. Pull-down assays revealed that the protein was able to interact with the recombinase, RadA, and the Holliday junction endonuclease, Hjc. stRadC2 inhibited the strand exchange activity of RadA and facilitated Hjc-mediated Holliday junction DNA cleavage in vitro. RT-PCR analysis revealed that stRadC2 transcription was immediately reduced after UV irradiation, but was restored to normal levels at the late stages of DNA repair. Our results suggest that stRadC2 may act as an anti-recombination factor in DNA recombinational repair in S. tokodaii.Science China. Life sciences 03/2012; 55(3):261-7. · 2.02 Impact Factor -
Article: Single-stranded DNA binding activity of XPBI, but not XPBII, from Sulfolobus tokodaii causes double-stranded DNA melting.
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ABSTRACT: XPB helicase is the largest subunit of transcription factor IIH (TFIIH), a ten-subunit protein complex essential for transcription initiation and nucleotide excision repair (NER) in Eukarya. Two XPB homologues (XPBI and XPBII) are present in the genome of most crenarchaeota, one of the two major phyla of archaea; however, the biochemical properties have not been fully characterized and their cellular roles have not been clearly defined. Here, we report that XPBI from the hyperthermophilic crenarchaeon Sulfolobus tokodaii (StoXPBI) is able to destabilize double-stranded DNA (dsDNA) helix independent of ATP (designated as dsDNA melting activity). This activity is inhibited by single-stranded DNA (ssDNA) and relies on the unique N-terminal domain of StoXPBI, which is also likely responsible for the intrinsic strong ssDNA binding activity of StoXPBI as revealed by deletion analysis. We demonstrate that the ATPase activity of StoXPBII is remarkably stimulated by StoBax1, a nuclease partner of StoXPBII. The role of the unique dsDNA melting activity of XPBI in NER in archaea was discussed.Extremophiles 01/2011; 15(1):67-76. · 2.94 Impact Factor
