title: Regulation of the human Suv3 helicase on DNA by inorganic cofactors.
abstract: Mitochondria are essential organelles and consequently proper expression and maintenance of the mitochondrial genome are indispensable for proper cell function. The mitochondrial Suv3 (SUPV3L1) helicase is known to have a central role in mitochondrial RNA metabolism and to be essential for maintenance of mitochondrial DNA stability. Here we have performed biochemical investigations to determine the potential regulation of the human Suv3 (hSuv3) helicase function by inorganic cofactors. We find that hSuv3 helicase and ATPase activity in vitro is strictly dependent on the presence of specific divalent cations. Interestingly, we show that divalent cations and nucleotide concentration have a direct effect on helicase substrate stability. Also, hSuv3 helicase is able to utilize several different nucleotide cofactors including both NTPs and dNTPs. Intriguingly, the potency of the individual nucleotide as energy source for hSuv3 unwinding differed depending on the included divalent cation and nucleotide concentration. At low concentrations, all four NTPs could support helicase activity with varying effectiveness depending on the included divalent cation. However, at higher nucleotide concentrations, only ATP was able to elicit the helicase activity of hSuv3. Consequently, we speculate that the capacity of hSuv3 DNA unwinding activity might be sensitive to the local availability of specific inorganic cofactors.
authors.affiliation: Danish Center of Molecular Gerontology and Danish Aging Research Center, University of Aarhus, Department of Molecular Biology and Genetics, Aarhus C DK-8000, Denmark.
authors.forename: Susanne T
authors.initials: ST
authors.lastname: Venø
authors.affiliation: Danish Center of Molecular Gerontology and Danish Aging Research Center, University of Aarhus, Department of Molecular Biology and Genetics, Aarhus C DK-8000, Denmark.
authors.forename: Marie B
authors.initials: MB
authors.lastname: Witt
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kulikowicz
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
authors.forename: Vilhelm A
authors.initials: VA
authors.lastname: Bohr
authors.affiliation: Danish Center of Molecular Gerontology and Danish Aging Research Center, University of Aarhus, Department of Molecular Biology and Genetics, Aarhus C DK-8000, Denmark. Electronic address: tvs@mb.au.dk.
authors.forename: Tinna
authors.initials: T
authors.lastname: Stevnsner
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D002413:Cations, Divalent / Q000494:pharmacology*; D003067:Coenzymes / Q000494:pharmacology*; D053487:DEAD-box RNA Helicases / Q000378:metabolism*; D004247:DNA / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008928:Mitochondria / Q000201:enzymology; D009711:Nucleotides / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D013379:Substrate Specificity
chemical_list: D002413:Cations, Divalent; D003067:Coenzymes; D009711:Nucleotides; D004247:DNA; D000251:Adenosine Triphosphatases; C469673:SUPV3L1 protein, human; D053487:DEAD-box RNA Helicases
keywords: Cofactor; DNA binding protein; Divalent cations; Helicase; Nucleotide