title: The N-terminal domain of human DNA helicase Rtel1 contains a redox active iron-sulfur cluster.
abstract: Human telomere length regulator Rtel1 is a superfamily II DNA helicase and is essential for maintaining proper length of telomeres in chromosomes. Here we report that the N-terminal domain of human Rtel1 (RtelN) expressed in Escherichia coli cells produces a protein that contains a redox active iron-sulfur cluster with the redox midpoint potential of -248 ± 10 mV (pH 8.0). The iron-sulfur cluster in RtelN is sensitive to hydrogen peroxide and nitric oxide, indicating that reactive oxygen/nitrogen species may modulate the DNA helicase activity of Rtel1 via modification of its iron-sulfur cluster. Purified RtelN retains a weak binding affinity for the single-stranded (ss) and double-stranded (ds) DNA in vitro. However, modification of the iron-sulfur cluster by hydrogen peroxide or nitric oxide does not significantly affect the DNA binding activity of RtelN, suggesting that the iron-sulfur cluster is not directly involved in the DNA interaction in the N-terminal domain of Rtel1.
authors.affiliation: Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Landry
authors.affiliation: Department of Biological Sciences, Louisiana State University, 202 Life Sciences Building, Baton Rouge, LA 70803, USA.
authors.forename: Huangen
authors.identifier: 0000-0002-4815-7336
authors.initials: H
authors.lastname: Ding
mesh_terms: D000595:Amino Acid Sequence; D004247:DNA / Q000235:genetics; D004265:DNA Helicases / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000378:metabolism; D010084:Oxidation-Reduction; D017434:Protein Structure, Tertiary / Q000235:genetics*; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D016415:Sequence Alignment; D013455:Sulfur / Q000378:metabolism*
chemical_list: D004277:DNA, Single-Stranded; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D013455:Sulfur; D004247:DNA; D006861:Hydrogen Peroxide; D007501:Iron; D004265:DNA Helicases