Human DNA helicase VIII: a DNA and RNA helicase corresponding to the G3BP protein, an element of the ras transduction pathway.
Human DNA helicase VIII (HDH VIII) was isolated in the course of a systematic study of the DNA unwinding enzymes present in human cells. From a HeLa cell nuclear extract a protein with an Mrof 68 kDa in SDS-PAGE was isolated, characterised and micro-sequenced. The enzyme shows ATP- and Mg2+-dependent activity is not stimulated by RPA, prefers partially unwound 3'-tailed substrates and moves along the bound strand in the 5' to 3' direction. HDH VIII can also unwind partial RNA/DNA and RNA/RNA duplexes. Microsequencing of the polypeptide showed that this enzyme corresponds to G3BP, an element of the Ras pathway which binds specifically to the GTPase-activating protein. HDH VIII/G3BP is analogous to the heterogeneous nuclear ribonucleoproteins and contains a sequence rich in RGG boxes similar to the C-terminal domain of HDH IV/nucleolin, another DNA and RNA helicase.
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International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste, Italy. 163-67404,Illkirch cedex-C. U. de Strasbourg,
Ochem
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Staub
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Falaschi
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D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism; D000595:Amino Acid Sequence; D004247:DNA / Q000378:metabolism; D004265:DNA Helicases / Q000737:chemistry / Q000378:metabolism; D004260:DNA Repair; D004268:DNA-Binding Proteins; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004591:Electrophoresis, Polyacrylamide Gel; D004706:Endodeoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D020690:GTPase-Activating Proteins; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D012313:RNA / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins / Q000378:metabolism*; D000097796:Nucleolin
D000251:Adenosine Triphosphatases; D004247:DNA; D004265:DNA Helicases; D004268:DNA-Binding Proteins; D043224:Deoxyribonuclease (Pyrimidine Dimer); D004706:Endodeoxyribonucleases; D029968:Escherichia coli Proteins; D020558:GTP Phosphohydrolases; D020690:GTPase-Activating Proteins; D010750:Phosphoproteins; D011506:Proteins; D012313:RNA; D016601:RNA-Binding Proteins; D020703:ras GTPase-Activating Proteins; D018631:ras Proteins; D000097796:Nucleolin; C059716:helD protein, E coli