Identification of human DNA helicase V with the far upstream element-binding protein.
The properties of human DNA helicase V (HDH V) were studied in greater detail following an improved purification procedure. From 450 g of cultured cells, <0.1 mg of pure protein was isolated. HDH V unwinds DNA unidirectionally by moving in the 3' to 5' direction along the bound strand in an ATP- and Mg(2+)-dependent fashion. The enzyme is not processive and can also unwind partial RNA-RNA duplexes such as HDH IV and HDH VIII. The M:(r) determined by SDS-PAGE (66 kDa) corresponds to that measured under native conditions, suggesting that HDH V exists as a monomer in the nucleus. Microsequencing of the purified HDH V shows that this enzyme is identical to the far upstream element-binding protein (FBP), a protein that stimulates the activity of the c-myc gene by binding specifically to the 'FUSE' DNA region localized upstream of its promoter. The sequence of HDH V/FBP contains RGG motifs like HDH IV/nucleolin, HDH VIII/G3BP as well as other human RNA and DNA helicases identified by other laboratories.
International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste, Italy.
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Vindigni
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Ochem
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Triolo
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Falaschi
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000201:enzymology; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004265:DNA Helicases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D016601:RNA-Binding Proteins; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; C492258:FUBP1 protein, human; D009841:Oligonucleotides; D016601:RNA-Binding Proteins; D004247:DNA; D004265:DNA Helicases