Human AlkB homologue 1 (ABH1) exhibits DNA lyase activity at abasic sites |
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| Authors: | Tina A. Müller Katheryn Meek Robert P. Hausinger |
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| Affiliation: | 1. Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States;2. Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, United States;3. Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States;1. Department of Pharmacology and Toxicology, Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, United States;2. Life Sciences Division, Lawrence Berkeley Laboratory, Berkeley, CA 94720, United States;3. Department of Biochemistry/Molecular Biology and Medicine, Indiana University Cancer Center, Indiana University Medical Center, Indianapolis, IN 46202, United States;4. Department of Medicine, University of Florida, Gainesville, FL 32610, United States;5. Lineberger Comprehensive Cancer Center, Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, United States;1. Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;2. Molecular Genetics Section, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;3. Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA;1. Planta Piloto de Ingeniería Química (PLAPIQUI-UNS-CONICET), Camino La Carrindanga Km 7, 8000 Bahía Blanca, Argentina;2. Thermodynamics Research Unit, School of Engineering, University of KwaZulu-Natal, Howard College Campus, King George V Avenue, Durban 4041, South Africa;3. Department of Chemistry and Materials Science Innovation & Modelling Research Focus Area, School of Mathematical and Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University (Mafikeng Campus), Private Bag X2046, Mmabatho 2735, South Africa;4. Institut de Recherche en Génie Chimique et Pétrolier (IRGCP), Paris Cedex, France;5. Département de Génie des Mines, de la Métallurgie et des Matériaux, Faculté des Sciences et de Génie, Université Laval, Québec, QC G1V0A6, Canada;1. Inha Research Institute for Medical Sciences, College of Medicine, Inha University, Incheon 400-712, Republic of Korea;2. Department of Pharmacology, College of Medicine, Inha University, Incheon 400-712, Republic of Korea;3. Department of Molecular Biomedicine, College of Medicine, Inha University, Incheon 400-712, Republic of Korea;4. Department of Parasitology, College of Medicine, Inha University, Incheon 400-712, Republic of Korea;1. Cardiothoracic Surgery, University of Colorado, Children''s Hospital Colorado, Aurora, Colorado;2. Cardiothoracic Surgery, University of Colorado Anschutz Medical Campus, Aurora, Colorado |
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| Abstract: | Bacterial AlkB and three human AlkB homologues (ABH1, ABH2, and ABH3) are Fe2+/2-oxoglutarate-dependent oxygenases that directly repair alkylation-damaged DNA. Here, we show that ABH1 unexpectedly has a second activity, cleaving DNA at abasic (AP) sites such as those arising spontaneously from alkylation-dependent depurination reactions. The DNA cleavage activity of ABH1 does not require added Fe2+ or 2-oxoglutarate, is not inhibited by EDTA, and is unaffected by mutation of the putative metal-binding residues, indicating that this activity arises from an active site distinct from that used for demethylation. AP-specific DNA cleavage was shown to occur by a lyase mechanism, rather than by hydrolysis, with the enzyme remaining associated with the DNA product. ABH1 can cleave at closely spaced AP-sites on opposite DNA strands yielding double-strand breaks in vitro and this reaction may relate to the physiological role of this unexpected AP lyase activity. |
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