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Hung SH, Elliott GI, Ramkumar TR, Burtnyak L, McGrenaghan CJ, Alkuzweny S, Quaiyum S, Iwata-Reuyl D, Pan X, Green BD, Kelly VP, de Crécy-Lagard V, Swairjo M. Structural basis of Qng1-mediated salvage of the micronutrient queuine from queuosine-5'-monophosphate as the biological substrate. Nucleic Acids Res 2023; 51:935-951. [PMID: 36610787 PMCID: PMC9881137 DOI: 10.1093/nar/gkac1231] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 12/02/2022] [Accepted: 12/10/2022] [Indexed: 01/09/2023] Open
Abstract
Eukaryotic life benefits from-and ofttimes critically relies upon-the de novo biosynthesis and supply of vitamins and micronutrients from bacteria. The micronutrient queuosine (Q), derived from diet and/or the gut microbiome, is used as a source of the nucleobase queuine, which once incorporated into the anticodon of tRNA contributes to translational efficiency and accuracy. Here, we report high-resolution, substrate-bound crystal structures of the Sphaerobacter thermophilus queuine salvage protein Qng1 (formerly DUF2419) and of its human ortholog QNG1 (C9orf64), which together with biochemical and genetic evidence demonstrate its function as the hydrolase releasing queuine from queuosine-5'-monophosphate as the biological substrate. We also show that QNG1 is highly expressed in the liver, with implications for Q salvage and recycling. The essential role of this family of hydrolases in supplying queuine in eukaryotes places it at the nexus of numerous (patho)physiological processes associated with queuine deficiency, including altered metabolism, proliferation, differentiation and cancer progression.
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Affiliation(s)
- Shr-Hau Hung
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
- The Viral Information Institute, San Diego State University, San Diego, CA, USA
| | - Gregory I Elliott
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
| | - Thakku R Ramkumar
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Lyubomyr Burtnyak
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Callum J McGrenaghan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Sana Alkuzweny
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
| | - Samia Quaiyum
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, PO Box 751 Portland State University, Portland, OR 97207, USA
| | - Xiaobei Pan
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, UK
| | - Brian D Green
- School of Biological Sciences, Institute for Global Food Security, Queen's University Belfast, Belfast, UK
| | - Vincent P Kelly
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, USA
- University of Florida Genetics Institute, Gainesville, FL 32610, USA
| | - Manal A Swairjo
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
- The Viral Information Institute, San Diego State University, San Diego, CA, USA
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2
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Franck C, Stéphane G, Julien C, Virginie G, Martine G, Norbert G, Fabrice C, Didier F, Josef SM, Bertrand C. Structural and functional determinants of the archaeal 8-oxoguanine-DNA glycosylase AGOG for DNA damage recognition and processing. Nucleic Acids Res 2022; 50:11072-11092. [PMID: 36300625 PMCID: PMC9638937 DOI: 10.1093/nar/gkac932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 08/31/2022] [Accepted: 10/25/2022] [Indexed: 11/29/2022] Open
Abstract
8-Oxoguanine (GO) is a major purine oxidation product in DNA. Because of its highly mutagenic properties, GO absolutely must be eliminated from DNA. To do this, aerobic and anaerobic organisms from the three kingdoms of life have evolved repair mechanisms to prevent its deleterious effect on genetic integrity. The major way to remove GO is the base excision repair pathway, usually initiated by a GO-DNA glycosylase. First identified in bacteria (Fpg) and eukaryotes (OGG1), GO-DNA glycosylases were more recently identified in archaea (OGG2 and AGOG). AGOG is the less documented enzyme and its mode of damage recognition and removing remains to be clarified at the molecular and atomic levels. This study presents a complete structural characterisation of apo AGOGs from Pyrococcus abyssi (Pab) and Thermococcus gammatolerans (Tga) and the first structure of Pab-AGOG bound to lesion-containing single- or double-stranded DNA. By combining X-ray structure analysis, site directed mutagenesis and biochemistry experiments, we identified key amino acid residues of AGOGs responsible for the specific recognition of the lesion and the base opposite the lesion and for catalysis. Moreover, a unique binding mode of GO, involving double base flipping, never observed for any other DNA glycosylases, is revealed. In addition to unravelling the properties of AGOGs, our study, through comparative biochemical and structural analysis, offers new insights into the evolutionary plasticity of DNA glycosylases across all three kingdoms of life.
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Affiliation(s)
- Coste Franck
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Goffinont Stéphane
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Cros Julien
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Gaudon Virginie
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Guérin Martine
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Garnier Norbert
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Confalonieri Fabrice
- Institut de Biologie Intégrative de la cellule (I2BC), UMR 9198 Université Paris-Saclay-CNRS-CEA , Bâtiment 21, Avenue de la Terrasse , F-91190 Gif-sur-Yvette , France
| | - Flament Didier
- Université de Brest, Ifremer, CNRS, Unité Biologie et Ecologie des Ecosystèmes marins Profonds (BEEP) , F-29280 Plouzané , France
| | - Suskiewicz Marcin Josef
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
| | - Castaing Bertrand
- Centre de Biophysique Moléculaire (CBM), UPR4301 CNRS, Université d’Orléans , CS 80054, rue Charles Sadron , F-45071 Orléans cedex 02 , France
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3
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Wang L, Jiang D, Zhang L. A thermophilic 8-oxoguanine DNA glycosylase from Thermococcus barophilus Ch5 is a new member of AGOG DNA glycosylase family. Acta Biochim Biophys Sin (Shanghai) 2022; 54:1801-1810. [PMID: 35713316 PMCID: PMC10157611 DOI: 10.3724/abbs.2022072] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 05/24/2022] [Indexed: 11/25/2022] Open
Abstract
8-Oxoguanine (8oxoG) in DNA is a major oxidized base that poses a severe threat to genome stability. To counteract the mutagenic effect generated by 8oxoG in DNA, cells have evolved 8oxoG DNA glycosylase (OGG) that can excise this oxidized base from DNA. Currently, OGG enzymes have been divided into three families: OGG1, OGG2 and AGOG (archaeal 8oxoG DNA glycosylase). Due to the limited reports, our understanding on AGOG enzymes remains incomplete. Herein, we present evidence that an AGOG from the hyperthermophilic euryarchaeon Ch5 (Tb-AGOG) excises 8oxoG from DNA at high temperature. The enzyme displays maximum efficiency at 75°C-95°C and at pH 9.0. As expected, Tb-AGOG is a bifunctional glycosylase that harbors glycosylase activity and AP (apurinic/apyrimidinic) lyase activity. Importantly, we reveal for the first time that residue D41 in Tb-AGOG is essential for 8oxoG excision and intermediate formation, but not essential for DNA binding or AP cleavage. Furthermore, residue E79 in Tb-AGOG is essential for 8oxoG excision and intermediate formation, and is partially involved in DNA binding and AP cleavage, which has not been described among the reported AGOG members to date. Overall, our work provides new insights into catalytic mechanism of AGOG enzymes.
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Affiliation(s)
- Lei Wang
- College of Environmental Science and EngineeringMarine Science & Technology InstituteYangzhou UniversityYangzhou225127China
| | - Donghao Jiang
- College of Environmental Science and EngineeringMarine Science & Technology InstituteYangzhou UniversityYangzhou225127China
| | - Likui Zhang
- College of Environmental Science and EngineeringMarine Science & Technology InstituteYangzhou UniversityYangzhou225127China
- Guangling CollegeYangzhou UniversityYangzhou225000China
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5
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Gehring AM, Zatopek KM, Burkhart BW, Potapov V, Santangelo TJ, Gardner AF. Biochemical reconstitution and genetic characterization of the major oxidative damage base excision DNA repair pathway in Thermococcus kodakarensis. DNA Repair (Amst) 2020; 86:102767. [PMID: 31841800 PMCID: PMC8061334 DOI: 10.1016/j.dnarep.2019.102767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/22/2019] [Accepted: 12/04/2019] [Indexed: 11/16/2022]
Abstract
Reactive oxygen species drive the oxidation of guanine to 8-oxoguanine (8oxoG), which threatens genome integrity. The repair of 8oxoG is carried out by base excision repair enzymes in Bacteria and Eukarya, however, little is known about archaeal 8oxoG repair. This study identifies a member of the Ogg-subfamily archaeal GO glycosylase (AGOG) in Thermococcus kodakarensis, an anaerobic, hyperthermophilic archaeon, and delineates its mechanism, kinetics, and substrate specificity. TkoAGOG is the major 8oxoG glycosylase in T. kodakarensis, but is non-essential. In addition to TkoAGOG, the major apurinic/apyrimidinic (AP) endonuclease (TkoEndoIV) required for archaeal base excision repair and cell viability was identified and characterized. Enzymes required for the archaeal oxidative damage base excision repair pathway were identified and the complete pathway was reconstituted. This study illustrates the conservation of oxidative damage repair across all Domains of life.
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Affiliation(s)
| | | | - Brett W Burkhart
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, United States
| | | | - Thomas J Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, United States
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6
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Zhang L, Li Y, Shi H, Zhang D, Yang Z, Oger P, Zheng J. Biochemical characterization and mutational studies of the 8-oxoguanine DNA glycosylase from the hyperthermophilic and radioresistant archaeon Thermococcus gammatolerans. Appl Microbiol Biotechnol 2019; 103:8021-8033. [PMID: 31372707 DOI: 10.1007/s00253-019-10031-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 07/08/2019] [Accepted: 07/13/2019] [Indexed: 12/22/2022]
Abstract
8-oxoguanine (GO) is a major lesion found in DNA that arises from guanine oxidation. The hyperthermophilic and radioresistant euryarchaeon Thermococcus gammatolerans encodes an archaeal GO DNA glycosylase (Tg-AGOG). Here, we characterized biochemically Tg-AGOG and probed its GO removal mechanism by mutational studies. Tg-AGOG can remove GO from DNA at high temperature through a β-elimination reaction. The enzyme displays an optimal temperature, ca.85-95 °C, and an optimal pH, ca.7.0-8.5. In addition, Tg-AGOG activity is independent on a divalent metal ion. However, both Co2+ and Cu2+ inhibit its activity. The enzyme activity is also inhibited by NaCl. Furthermore, Tg-AGOG specifically cleaves GO-containing dsDNA in the order: GO:C, GO:T, GO:A, and GO:G. Moreover, the temperature dependence of cleavage rates of the enzyme was determined, and from this, the activation energy for GO removal from DNA was first estimated to be 16.9 ± 0.9 kcal/mol. In comparison with the wild-type Tg-AGOG, the R197A mutant has a reduced cleavage activity for GO-containing DNA, whereas both the P193A and F167A mutants exhibit similar cleavage activities for GO-containing DNA. While the mutations of P193 and F167 to Ala lead to increased binding, the mutation of R197 to Ala had no significant effect on binding. These observations suggest that residue R197 is involved in catalysis, and residues P193 and F167 are flexible for conformational change.
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Affiliation(s)
- Likui Zhang
- Department of Environmental Science and Engineering Marine Science & Technology Institute, Yangzhou University, Yangzhou, Jiangsu, China.
| | - Yuting Li
- Department of Environmental Science and Engineering Marine Science & Technology Institute, Yangzhou University, Yangzhou, Jiangsu, China
| | - Haoqiang Shi
- Department of Environmental Science and Engineering Marine Science & Technology Institute, Yangzhou University, Yangzhou, Jiangsu, China
| | - Dai Zhang
- College of Plant Protection, Agricultural University of Hebei, Baoding City, 071001, Hebei Province, China
| | - Zhihui Yang
- College of Plant Protection, Agricultural University of Hebei, Baoding City, 071001, Hebei Province, China.
| | - Philippe Oger
- Univ Lyon, INSA de Lyon, CNRS UMR 5240, Villeurbanne, France.
| | - Jianting Zheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China
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7
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CX3CL1 binding protein-2 (CBP2) of Plasmodium falciparum binds nucleic acids. Int J Biol Macromol 2019; 138:996-1005. [PMID: 31356937 DOI: 10.1016/j.ijbiomac.2019.07.178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 12/21/2022]
Abstract
Several exported Plasmodium falciparum (Pf) proteins contribute to malaria biology through their involvement in cytoadherence, immune evasion and host cell remodelling. Many of these exported proteins and other host molecules are present in iRBC (infected red blood cell) generated extracellular vesicles (EVs), which are responsible for host cell modification and parasite development. CX3CL1 binding proteins (CBPs) present on the surface of iRBCs have been reported to contribute to cytoadhesion by binding with the chemokine 'CX3CL1' via their extracellular domains. Here, we have characterized the cytoplasmic domain of CBP2 to understand its function in parasite biology using biochemical and biophysical methods. Recombinant cytoplasmic CBP2 (cCBP2) binds nucleic acids showing interaction with DNA/RNA. cCBP2 shows dimer formation under non-reducing conditions highlighting the role of disulphide bonds in its oligomerization while ATP binding leads to structural changes in the protein. In vitro interaction studies depict its binding with a Maurer's cleft resident protein 'PfSBP1', which is influenced by ATP binding of cCBP2. Our results suggest CBP2 as a two-transmembrane (2TM) receptor responsible for targeting EVs and delivering cargo to host endothelial cells. We propose CBP2 as an important molecule having roles in cytoadherence and immune modulation through its extracellular and cytoplasmic domains respectively.
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8
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Sinitsky MY, Minina VI, Asanov MA, Yuzhalin AE, Ponasenko AV, Druzhinin VG. Association of DNA repair gene polymorphisms with genotoxic stress in underground coal miners. Mutagenesis 2018; 32:501-509. [PMID: 28992182 DOI: 10.1093/mutage/gex018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In underground coal mining, numerous harmful substances and ionising radiation pose a major threat to the occupational safety and health of workers. Because cell DNA repair machinery eliminates genotoxic stress conferred by these agents, we examined whether single nucleotide polymorphisms in hOGG1 (rs1052133), XRCC1 (rs25487), ADPRT (rs1136410), XRCC4 (rs6869366) and LIG4 (rs1805388) genes modulate the genotoxic damage assessed by the cytokinesis-block micronucleus assay in lymphocytes from 143 underground coal miners and 127 healthy non-exposed males. We also analyzed models of gene-gene interactions associated with increased cytogenetic damage in coal miners and determined 'protective' and 'risk' combinations of alleles. We showed that miners with the G/G genotype of the hOGG1 (rs1052133) gene had a significantly increased frequency of binucleated lymphocytes with micronuclei (13.17‰, 95% CI = 10.78-15.56) compared to the C/C genotype carriers (10.35‰, 95% CI = 9.59-11.18). In addition, in the exposed group this indicator was significantly increased in carriers of the T/T genotype of the LIG4 (rs1805388) gene compared to miners harbouring the C/T genotype (13.00‰, 95% CI = 10.96-15.04 and 9.69‰, 95% CI = 8.32-11.06, respectively). Using the multifactor dimensionality reduction method, we found the three-locus model of gene-gene interactions hOGG1 (rs1052133) × ADPRT (rs1136410) × XRCC4 (rs6869366) associated with high genotoxic risk in coal miners. These results indicate that the studied polymorphisms and their combinations are associated with cytogenetic status in miners and may be used as molecular predictors of occupational risks in underground coal mines.
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Affiliation(s)
- Maxim Yu Sinitsky
- Research Institute for Complex Issues of Cardiovascular Diseases, Sosnovy Boulevard 6, 650002 Kemerovo, Russia.,Federal Research Center of Coal and Coal Chemistry, Leningradsky Avenue 10, 650065 Kemerovo, Russia
| | - Varvara I Minina
- Federal Research Center of Coal and Coal Chemistry, Leningradsky Avenue 10, 650065 Kemerovo, Russia.,Department of Genetics, Kemerovo State University, Krasnaya Street 6, 650043 Kemerovo, Russia
| | - Maxim A Asanov
- Federal Research Center of Coal and Coal Chemistry, Leningradsky Avenue 10, 650065 Kemerovo, Russia
| | - Arseniy E Yuzhalin
- Department of Oncology, CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Anastasia V Ponasenko
- Research Institute for Complex Issues of Cardiovascular Diseases, Sosnovy Boulevard 6, 650002 Kemerovo, Russia
| | - Vladimir G Druzhinin
- Federal Research Center of Coal and Coal Chemistry, Leningradsky Avenue 10, 650065 Kemerovo, Russia.,Department of Genetics, Kemerovo State University, Krasnaya Street 6, 650043 Kemerovo, Russia
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9
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Boiteux S, Coste F, Castaing B. Repair of 8-oxo-7,8-dihydroguanine in prokaryotic and eukaryotic cells: Properties and biological roles of the Fpg and OGG1 DNA N-glycosylases. Free Radic Biol Med 2017; 107:179-201. [PMID: 27903453 DOI: 10.1016/j.freeradbiomed.2016.11.042] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 11/22/2016] [Accepted: 11/25/2016] [Indexed: 01/23/2023]
Abstract
Oxidatively damaged DNA results from the attack of sugar and base moieties by reactive oxygen species (ROS), which are formed as byproducts of normal cell metabolism and during exposure to endogenous or exogenous chemical or physical agents. Guanine, having the lowest redox potential, is the DNA base the most susceptible to oxidation, yielding products such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2-6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG). In DNA, 8-oxoG was shown to be mutagenic yielding GC to TA transversions upon incorporation of dAMP opposite this lesion by replicative DNA polymerases. In prokaryotic and eukaryotic cells, 8-oxoG is primarily repaired by the base excision repair pathway (BER) initiated by a DNA N-glycosylase, Fpg and OGG1, respectively. In Escherichia coli, Fpg cooperates with MutY and MutT to prevent 8-oxoG-induced mutations, the "GO-repair system". In Saccharomyces cerevisiae, OGG1 cooperates with nucleotide excision repair (NER), mismatch repair (MMR), post-replication repair (PRR) and DNA polymerase η to prevent mutagenesis. Human and mouse cells mobilize all these pathways using OGG1, MUTYH (MutY-homolog also known as MYH), MTH1 (MutT-homolog also known as NUDT1), NER, MMR, NEILs and DNA polymerases η and λ, to prevent 8-oxoG-induced mutations. In fact, mice deficient in both OGG1 and MUTYH develop cancer in different organs at adult age, which points to the critical impact of 8-oxoG repair on genetic stability in mammals. In this review, we will focus on Fpg and OGG1 proteins, their biochemical and structural properties as well as their biological roles. Other DNA N-glycosylases able to release 8-oxoG from damaged DNA in various organisms will be discussed. Finally, we will report on the role of OGG1 in human disease and the possible use of 8-oxoG DNA N-glycosylases as therapeutic targets.
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Affiliation(s)
- Serge Boiteux
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45072 Orléans, France.
| | - Franck Coste
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45072 Orléans, France
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45072 Orléans, France.
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Characterization of a Thermostable 8-Oxoguanine DNA Glycosylase Specific for GO/N Mismatches from the Thermoacidophilic Archaeon Thermoplasma volcanium. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2016; 2016:8734894. [PMID: 27799846 PMCID: PMC5069365 DOI: 10.1155/2016/8734894] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 08/27/2016] [Accepted: 09/07/2016] [Indexed: 01/09/2023]
Abstract
The oxidation of guanine (G) to 7,8-dihydro-8-oxoguanine (GO) forms one of the major DNA lesions generated by reactive oxygen species (ROS). The GO can be corrected by GO DNA glycosylases (Ogg), enzymes involved in base excision repair (BER). Unrepaired GO induces mismatched base pairing with adenine (A); as a result, the mismatch causes a point mutation, from G paired with cytosine (C) to thymine (T) paired with adenine (A), during DNA replication. Here, we report the characterization of a putative Ogg from the thermoacidophilic archaeon Thermoplasma volcanium. The 204-amino acid sequence of the putative Ogg (TVG_RS00315) shares significant sequence homology with the DNA glycosylases of Methanocaldococcus jannaschii (MjaOgg) and Sulfolobus solfataricus (SsoOgg). The six histidine-tagged recombinant TVG_RS00315 protein gene was expressed in Escherichia coli and purified. The Ogg protein is thermostable, with optimal activity near a pH of 7.5 and a temperature of 60°C. The enzyme displays DNA glycosylase, and apurinic/apyrimidinic (AP) lyase activities on GO/N (where N is A, T, G, or C) mismatch; yet it cannot eliminate U from U/G or T from T/G, as mismatch glycosylase (MIG) can. These results indicate that TvoOgg-encoding TVG_RS00315 is a member of the Ogg2 family of T. volcanium.
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11
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Zallot R, Brochier-Armanet C, Gaston KW, Forouhar F, Limbach PA, Hunt JF, de Crécy-Lagard V. Plant, animal, and fungal micronutrient queuosine is salvaged by members of the DUF2419 protein family. ACS Chem Biol 2014; 9:1812-25. [PMID: 24911101 PMCID: PMC4136680 DOI: 10.1021/cb500278k] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
Queuosine (Q) is a modification found
at the wobble position of
tRNAs with GUN anticodons. Although Q is present in most eukaryotes
and bacteria, only bacteria can synthesize Q de novo. Eukaryotes acquire queuine (q), the free base of Q, from diet and/or
microflora, making q an important but under-recognized micronutrient
for plants, animals, and fungi. Eukaryotic type tRNA-guanine transglycosylases
(eTGTs) are composed of a catalytic subunit (QTRT1) and a homologous
accessory subunit (QTRTD1) forming a complex that catalyzes q insertion
into target tRNAs. Phylogenetic analysis of eTGT subunits revealed
a patchy distribution pattern in which gene losses occurred independently
in different clades. Searches for genes co-distributing with eTGT
family members identified DUF2419 as a potential Q salvage protein
family. This prediction was experimentally validated in Schizosaccharomyces
pombe by confirming that Q was present by analyzing tRNAAsp with anticodon GUC purified from wild-type cells and by
showing that Q was absent from strains carrying deletions in the QTRT1
or DUF2419 encoding genes. DUF2419 proteins occur in most Eukarya
with a few possible cases of horizontal gene transfer to bacteria.
The universality of the DUF2419 function was confirmed by complementing
the S. pombe mutant with the Zea mays (maize), human, and Sphaerobacter thermophilus homologues.
The enzymatic function of this family is yet to be determined, but
structural similarity with DNA glycosidases suggests a ribonucleoside
hydrolase activity.
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Affiliation(s)
- Rémi Zallot
- Department
of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, United States
| | - Céline Brochier-Armanet
- Université
Lyon 1, CNRS, UMR5558, Laboratoire de Biométrie et Biologie
Evolutive, Université de Lyon, 69622 Villeurbanne, France
| | - Kirk W. Gaston
- Rieveschl
Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Farhad Forouhar
- Department
of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - Patrick A. Limbach
- Rieveschl
Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - John F. Hunt
- Department
of Biological Sciences and Northeast Structural Genomics Consortium, Columbia University, New York, New York 10027, United States
| | - Valérie de Crécy-Lagard
- Department
of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611, United States
- University of Florida Genetics Institute, Gainesville, Florida 32611, United States
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12
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Yu H, Yang M, Zhang XE, Bi L, Jiang T. Crystal structures of MBOgg1 in complex with two abasic DNA ligands. J Struct Biol 2012; 181:252-63. [PMID: 23246782 DOI: 10.1016/j.jsb.2012.12.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/29/2012] [Accepted: 12/02/2012] [Indexed: 11/16/2022]
Abstract
7,8-Dihydro-8-oxoguanine (8-oxoG) is one of the most common oxidative DNA lesions. 8-oxoguanine DNA glycosylases (Oggs) detect and excise 8-oxoG through a multiple-step process. To better understand the basis for estranged base recognition, we have solved the crystal structures of MBOgg1, the 8-oxoguanine DNA glycosylase of Thermoanaerobacter tengcongensis, in complex with DNA containing a tetrahydrofuranyl site (THF, a stable abasic site analog) paired with an estranged cytosine (MBOgg1/DNA(THF:C)) or thymine (MBOgg1/DNA(THF:T)). Different states of THF (extrahelical or intrahelical) are observed in the two complexes of the ASU of MBOgg1/DNA(THF:C) structure. Analyses of their different interaction modes reveal that variable contacts on the 5' region flanking the THF abasic site are correlated with the states of the THF. Comparison of MBOgg1/DNA(THF:T) with MBOgg1/DNA(THF:C) indicates that the non-preferred estranged T may affect MBOgg1's contacts with the 5' flank of the lesion strand. Furthermore, we identified a region in MBOgg1 that is rich in positive charges and interacts with the 5' region flanking the lesion. This region is conserved only in non-eukaryotic Oggs, and additional mutagenesis and biochemical assays reveal that it may contribute to the distinct estranged base specificities between eukaryotic and non-eukaryotic Oggs.
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Affiliation(s)
- Hongjun Yu
- National Key Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Chaoyang District, Beijing 100101, China
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13
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Brooks SC, Adhikary S, Rubinson EH, Eichman BF. Recent advances in the structural mechanisms of DNA glycosylases. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1834:247-71. [PMID: 23076011 DOI: 10.1016/j.bbapap.2012.10.005] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 09/24/2012] [Accepted: 10/05/2012] [Indexed: 02/06/2023]
Abstract
DNA glycosylases safeguard the genome by locating and excising a diverse array of aberrant nucleobases created from oxidation, alkylation, and deamination of DNA. Since the discovery 28years ago that these enzymes employ a base flipping mechanism to trap their substrates, six different protein architectures have been identified to perform the same basic task. Work over the past several years has unraveled details for how the various DNA glycosylases survey DNA, detect damage within the duplex, select for the correct modification, and catalyze base excision. Here, we provide a broad overview of these latest advances in glycosylase mechanisms gleaned from structural enzymology, highlighting features common to all glycosylases as well as key differences that define their particular substrate specificities.
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Affiliation(s)
- Sonja C Brooks
- Department of Biological Sciences and Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
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14
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Faucher F, Doublié S, Jia Z. 8-oxoguanine DNA glycosylases: one lesion, three subfamilies. Int J Mol Sci 2012; 13:6711-6729. [PMID: 22837659 PMCID: PMC3397491 DOI: 10.3390/ijms13066711] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 05/14/2012] [Accepted: 05/24/2012] [Indexed: 11/24/2022] Open
Abstract
Amongst the four bases that form DNA, guanine is the most susceptible to oxidation, and its oxidation product, 7,8-dihydro-8-oxoguanine (8-oxoG) is the most prevalent base lesion found in DNA. Fortunately, throughout evolution cells have developed repair mechanisms, such as the 8-oxoguanine DNA glycosylases (OGG), which recognize and excise 8-oxoG from DNA thereby preventing the accumulation of deleterious mutations. OGG are divided into three subfamilies, OGG1, OGG2 and AGOG, which are all involved in the base excision repair (BER) pathway. The published structures of OGG1 and AGOG, as well as the recent availability of OGG2 structures in both apo- and liganded forms, provide an excellent opportunity to compare the structural and functional properties of the three OGG subfamilies. Among the observed differences, the three-dimensional fold varies considerably between OGG1 and OGG2 members, as the latter lack the A-domain involved in 8-oxoG binding. In addition, all three OGG subfamilies bind 8-oxoG in a different manner even though the crucial interaction between the enzyme and the protonated N7 of 8-oxoG is conserved. Finally, the three OGG subfamilies differ with respect to DNA binding properties, helix-hairpin-helix motifs, and specificity for the opposite base.
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Affiliation(s)
- Frédérick Faucher
- Department of Biomedical and Molecular Sciences, Queen’s University, 18 Stuart Street, Kingston, K7L 3N6, Canada
- Authors to whom correspondence should be addressed; E-Mails: (F.F.); (Z.J.); Tel.: +613-533-6277 (Z.J.); Fax: +613-533-2497 (Z.J.)
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, E314A Given Building, 89 Beaumont Avenue, Burlington, VT 05405, USA; E-Mail:
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen’s University, 18 Stuart Street, Kingston, K7L 3N6, Canada
- Authors to whom correspondence should be addressed; E-Mails: (F.F.); (Z.J.); Tel.: +613-533-6277 (Z.J.); Fax: +613-533-2497 (Z.J.)
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15
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Faucher F, Wallace SS, Doublié S. The C-terminal lysine of Ogg2 DNA glycosylases is a major molecular determinant for guanine/8-oxoguanine distinction. J Mol Biol 2010; 397:46-56. [PMID: 20083120 DOI: 10.1016/j.jmb.2010.01.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Revised: 01/10/2010] [Accepted: 01/12/2010] [Indexed: 11/19/2022]
Abstract
7,8-Dihydro-8-oxoguanine (8-oxoG) is a major oxidative lesion found in DNA. The 8-oxoguanine DNA glycosylases (Ogg) responsible for the removal of 8-oxoG are divided into three families Ogg1, Ogg2 and AGOG. The Ogg2 members are devoid of the recognition loop used by Ogg1 to discriminate between 8-oxoG and guanine and it was unclear until recently how Ogg2 enzymes recognize the oxidized base. We present here the first crystallographic structure of an Ogg2 member, Methanocaldococcus janischii Ogg, in complex with a DNA duplex containing the 8-oxoG lesion. This structure highlights the crucial role of the C-terminal lysine, strictly conserved in Ogg2, in the recognition of 8-oxoG. The structure also reveals that Ogg2 undergoes a conformational change upon DNA binding similar to that observed in Ogg1 glycosylases. Furthermore, this work provides a structural rationale for the lack of opposite base specificity in this family of enzymes.
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Affiliation(s)
- Frédérick Faucher
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Stafford Hall, 95 Carrigan Drive, Burlington, VT 05405-0068, USA
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16
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Structural basis for the lack of opposite base specificity of Clostridium acetobutylicum 8-oxoguanine DNA glycosylase. DNA Repair (Amst) 2009; 8:1283-9. [PMID: 19747886 DOI: 10.1016/j.dnarep.2009.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 08/05/2009] [Accepted: 08/10/2009] [Indexed: 11/20/2022]
Abstract
7,8-Dihydro-8-oxoguanine (8-oxoG) is the major oxidative product of guanine and the most prevalent base lesion observed in DNA molecules. Because 8-oxoG has the capability to form a Hoogsteen pair with adenine (8-oxoG:A) in addition to a normal Watson-Crick pair with cytosine (8-oxoG:C), this lesion can lead to a G:C-->T:A transversion after replication. However, 8-oxoG is recognized and excised by the 8-oxoguanine DNA glycosylase (Ogg) of the base excision repair pathway. Members of the Ogg1 family usually display a strong preference for a C opposite the lesion. In contrast, the atypical Ogg1 from Clostridium actetobutylicum (CacOgg) can excise 8-oxoG when paired with either one of the four bases, albeit with a preference for C and A. Here we describe the first high-resolution crystal structures of CacOgg in complex with duplex DNA containing the 8-oxoG lesion paired to cytosine and to adenine. A structural comparison with human OGG1 provides a rationale for the lack of opposite base specificity displayed by the bacterial Ogg.
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17
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Faucher F, Duclos S, Bandaru V, Wallace SS, Doublié S. Crystal structures of two archaeal 8-oxoguanine DNA glycosylases provide structural insight into guanine/8-oxoguanine distinction. Structure 2009; 17:703-12. [PMID: 19446526 DOI: 10.1016/j.str.2009.03.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Revised: 02/06/2009] [Accepted: 03/12/2009] [Indexed: 12/16/2022]
Abstract
Among the four DNA bases, guanine is particularly vulnerable to oxidative damage and the most common oxidative product, 7,8-dihydro-8-oxoguanine (8-oxoG), is the most prevalent lesion observed in DNA molecules. Fortunately, 8-oxoG is recognized and excised by the 8-oxoguanine DNA glycosylase (Ogg) of the base excision repair pathway. Ogg enzymes are divided into three separate families, namely, Ogg1, Ogg2, and archaeal GO glycosylase (AGOG). To date, structures of members of both Ogg1 and AGOG families are known but no structural information is available for members of Ogg2. Here we describe the first crystal structures of two archaeal Ogg2: Methanocaldococcus janischii Ogg and Sulfolobus solfataricus Ogg. A structural comparison with OGG1 and AGOG suggested that the C-terminal lysine of Ogg2 may play a key role in discriminating between guanine and 8-oxoG. This prediction was substantiated by measuring the glycosylase/lyase activity of a C-terminal deletion mutant of MjaOgg.
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Affiliation(s)
- Frédérick Faucher
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Stafford Hall, Burlington, VT 05405-0068, USA
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18
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Dalhus B, Laerdahl JK, Backe PH, Bjørås M. DNA base repair--recognition and initiation of catalysis. FEMS Microbiol Rev 2009; 33:1044-78. [PMID: 19659577 DOI: 10.1111/j.1574-6976.2009.00188.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Endogenous DNA damage induced by hydrolysis, reactive oxygen species and alkylation modifies DNA bases and the structure of the DNA duplex. Numerous mechanisms have evolved to protect cells from these deleterious effects. Base excision repair is the major pathway for removing base lesions. However, several mechanisms of direct base damage reversal, involving enzymes such as transferases, photolyases and oxidative demethylases, are specialized to remove certain types of photoproducts and alkylated bases. Mismatch excision repair corrects for misincorporation of bases by replicative DNA polymerases. The determination of the 3D structure and visualization of DNA repair proteins and their interactions with damaged DNA have considerably aided our understanding of the molecular basis for DNA base lesion repair and genome stability. Here, we review the structural biochemistry of base lesion recognition and initiation of one-step direct reversal (DR) of damage as well as the multistep pathways of base excision repair (BER), nucleotide incision repair (NIR) and mismatch repair (MMR).
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Affiliation(s)
- Bjørn Dalhus
- Centre for Molecular Biology and Neuroscience (CMBN), Rikshospitalet University Hospital, Oslo, Norway
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19
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Lingaraju GM, Prota AE, Winkler FK. Mutational studies of Pa-AGOG DNA glycosylase from the hyperthermophilic crenarchaeon Pyrobaculum aerophilum. DNA Repair (Amst) 2009; 8:857-64. [PMID: 19410520 DOI: 10.1016/j.dnarep.2009.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Accepted: 03/27/2009] [Indexed: 01/27/2023]
Abstract
In all organisms studied to date, 8-oxoguanine (GO), an important oxidation product of guanine, is removed by highly conserved GO DNA glycosylases. The hyperthermophilic crenarchaeon Pyrobaculum aerophilum encodes a GO DNA glycosylase, Pa-AGOG (Archaeal GO DNA glycosylase) which has become the founding member of a new family within the HhH-GPD superfamily of DNA glycosylases based on unique structural and functional characteristics. In this study, we made quantitative measurements of the DNA glycosylase activity of Pa-AGOG wild type and some engineered variants under single turnover conditions. The mutagenesis study includes residues Trp222 (W222A and W222F), Trp69 (W69F), Gln31 (Q31S) and Lys147 (K147Q) all of which are involved in GO recognition and Asp172 (D172N and D172Q) and Lys140 (K140Q) that are involved in catalysis. Pa-AGOG prefers GO/G mispairs for both base excision and base excision/beta-lyase activities. The mutagenesis studies show that base-stacking between GO and Trp222 is very important for recognition. The contact between Trp69 and the 8-oxo group was found to be dispensable, while that to N7 by Gln31 is indispensable for GO recognition. In contrast to human OGG1 the catalytic mutant, D172Q did not show detectable glycosylase activity. Pa-AGOG mutants K140Q, D172N and D172Q did bind GO containing single-stranded DNA more tightly than double-stranded DNA containing a GO/C base pair. Our studies confirm and extend the unique characteristics of Pa-AGOG, which distinguish it from other mesophilic and thermostable GO DNA glycosylases.
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20
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Faucher F, Robey-Bond SM, Wallace SS, Doublié S. Structural characterization of Clostridium acetobutylicum 8-oxoguanine DNA glycosylase in its apo form and in complex with 8-oxodeoxyguanosine. J Mol Biol 2009; 387:669-79. [PMID: 19361427 DOI: 10.1016/j.jmb.2009.01.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/23/2009] [Accepted: 01/31/2009] [Indexed: 10/21/2022]
Abstract
DNA is subject to a multitude of oxidative damages generated by oxidizing agents from metabolism and exogenous sources and by ionizing radiation. Guanine is particularly vulnerable to oxidation, and the most common oxidative product 8-oxoguanine (8-oxoG) is the most prevalent lesion observed in DNA molecules. 8-OxoG can form a normal Watson-Crick pair with cytosine (8-oxoG:C), but it can also form a stable Hoogsteen pair with adenine (8-oxoG:A), leading to a G:C-->T:A transversion after replication. Fortunately, 8-oxoG is recognized and excised by either of two DNA glycosylases of the base excision repair pathway: formamidopyrimidine-DNA glycosylase and 8-oxoguanine DNA glycosylase (Ogg). While Clostridium acetobutylicum Ogg (CacOgg) DNA glycosylase can specifically recognize and remove 8-oxoG, it displays little preference for the base opposite the lesion, which is unusual for a member of the Ogg1 family. This work describes the crystal structures of CacOgg in its apo form and in complex with 8-oxo-2'-deoxyguanosine. A structural comparison between the apo form and the liganded form of the enzyme reveals a structural reorganization of the C-terminal domain upon binding of 8-oxoG, similar to that reported for human OGG1. A structural comparison of CacOgg with human OGG1, in complex with 8-oxoG containing DNA, provides a structural rationale for the lack of opposite base specificity displayed by CacOgg.
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Affiliation(s)
- Frédérick Faucher
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Stafford Hall, 95 Carrigan Drive, Burlington, VT 05405-0068, USA
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21
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Bowman BR, Lee S, Wang S, Verdine GL. Structure of the E. coli DNA glycosylase AlkA bound to the ends of duplex DNA: a system for the structure determination of lesion-containing DNA. Structure 2008; 16:1166-74. [PMID: 18682218 DOI: 10.1016/j.str.2008.04.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Revised: 04/23/2008] [Accepted: 04/30/2008] [Indexed: 10/21/2022]
Abstract
The constant attack on DNA by endogenous and exogenous agents gives rise to nucleobase modifications that cause mutations, which can lead to cancer. Visualizing the effects of these lesions on the structure of duplex DNA is key to understanding their biologic consequences. The most definitive method of obtaining such structures, X-ray crystallography, is troublesome to employ owing to the difficulty of obtaining diffraction-quality crystals of DNA. Here, we present a crystallization system that uses a protein, the DNA glycosylase AlkA, as a scaffold to mediate the crystallization of lesion-containing duplex DNA. We demonstrate the use of this system to facilitate the rapid structure determination of DNA containing the lesion 8-oxoguanine in several different sequence contexts, and also deoxyinosine and 1,N(6)-ethenoadenine, each stabilized as the corresponding 2'-flouro analog. The structures of 8-oxoguanine provide a correct atomic-level view of this important endogenous lesion in DNA.
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Affiliation(s)
- Brian R Bowman
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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22
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23
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Millen AL, Archibald LAB, Hunter KC, Wetmore SD. A kinetic and thermodynamic study of the glycosidic bond cleavage in deoxyuridine. J Phys Chem B 2007; 111:3800-12. [PMID: 17388517 DOI: 10.1021/jp063841m] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Density functional theory was used to study the thermodynamics and kinetics for the glycosidic bond cleavage in deoxyuridine. Two reaction pathways were characterized for the unimolecular decomposition in vacuo. However, these processes are associated with large reaction barriers and highly endothermic reaction energies, which is in agreement with experiments that suggest a (water) nucleophile is required for the nonenzymatic glycosidic bond cleavage. Two (S(N)1 and S(N)2) reaction pathways were characterized for direct hydrolysis of the glycosidic bond by a single water molecule; however, both pathways also involve very large barriers. Activation of the water nucleophile via partial proton abstraction steadily decreases the barrier and leads to a more exothermic reaction energy as the proton affinity of the molecule interacting with water increases. Indeed, our data suggests that the barrier heights and reaction energies range from that for hydrolysis by water to that for hydrolysis by the hydroxyl anion, which represents the extreme of (full) water activation (deprotonation). Hydrogen bonds between small molecules (hydrogen fluoride, water, or ammonia) and the nucleobase were found to further decrease the barrier and overall reaction energy but not to the extent that the same hydrogen-bonding interactions increase the acidity of the nucleobase. Our results suggest that the nature of the nucleophile plays a more important role in reducing the barrier to glycosidic bond cleavage than the nature of the small molecule bound, and models with more than one hydrogen fluoride molecule interacting with the nucleobase provide further support for this conclusion. Our results lead to a greater fundamental understanding of the effects of the nucleophile, activation of the nucleophile, and interactions with the nucleobase for this important biological reaction.
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Affiliation(s)
- Andrea L Millen
- Department of Chemistry, Mount Allison University, 63C York Street, Sackville, New Brunswick E4L 1G8, Canada
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24
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Hunter KC, Wetmore SD. Environmental Effects on the Enhancement in Natural and Damaged DNA Nucleobase Acidity Because of Discrete Hydrogen-Bonding Interactions. J Phys Chem A 2007; 111:1933-42. [PMID: 17302396 DOI: 10.1021/jp066641j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present study uses density functional theory to carefully consider the effects of the environment on the enhancement in (natural and damaged) DNA nucleobase acidities because of multiple hydrogen-bonding interactions. Although interactions with one small molecule can increase the acidity of the nucleobases by up to 60 kJ mol-1 in the gas phase, the maximum increase in enzymatic-like environments is expected to be approximately 40 kJ mol-1, which reduces to approximately 30 kJ mol-1 in water. Furthermore, the calculated (simultaneous) effects of two, three, or four molecules are increasingly less than the sum of the individual (additive) effects with an increase in the number and acidity of the small molecules bound or the dielectric constant of the solvent. Regardless of these trends, our calculations reveal that additional hydrogen-bonding interactions will have a significant effect on nucleobase acidity in a variety of environments, where the exact magnitude of the effect depends on the properties of the small molecule bound, the nucleobase binding site, and the solvent. The maximum increase in nucleobase acidity because of interactions with up to four small molecules is approximately 80 kJ mol-1 in enzymatic-like environments (or 65 kJ mol-1 in water). These results suggest that hydrogen-bonding interactions likely play an important role in many biological processes by changing the physical and chemical properties of the nucleobases.
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Affiliation(s)
- Ken C Hunter
- Department of Chemistry, Mount Allison University, 63C York Street, Sackville, New Brunswick, E4L 1G8, Canada
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25
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Schubiger PA. Molecular imaging with PET--open questions? ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2007:1-13. [PMID: 17172150 DOI: 10.1007/978-3-540-49527-7_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Molecular imaging has become a very popular term in medicine and can be interpreted in many different ways. It is argued that a correct definition should be 'in vivo imaging of biological processes with appropriate molecular probes'. The real challenge in molecular imaging therefore is the search for the 'optimal' molecular imaging probes. It is discussed that nuclear, optical and magnetic probes can be used. However, only PET probes have the high sensitivity to be applied generally. To develop PET probes efficiently, methods for the in vitro and in vivo characterization are discussed and alternatives compared. Some open questions with respect to the reliability of animal imaging and evaluation of the imaging data will be elucidated.
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Affiliation(s)
- P A Schubiger
- Animal Imaging Center-PET, Center for Radiopharmaceutical Science of ETH, PSI and USZ, Zürich, Switzerland.
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26
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Affiliation(s)
- Patrick J O'Brien
- Department of Biological Chemistry, University of Michigan, Ann Arbor, 48109-0606, USA.
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27
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Berti PJ, McCann JAB. Toward a detailed understanding of base excision repair enzymes: transition state and mechanistic analyses of N-glycoside hydrolysis and N-glycoside transfer. Chem Rev 2006; 106:506-55. [PMID: 16464017 DOI: 10.1021/cr040461t] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Paul J Berti
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada.
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28
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Huffman JL, Sundheim O, Tainer JA. DNA base damage recognition and removal: new twists and grooves. Mutat Res 2005; 577:55-76. [PMID: 15941573 DOI: 10.1016/j.mrfmmm.2005.03.012] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 03/29/2005] [Accepted: 03/29/2005] [Indexed: 11/24/2022]
Abstract
The discoveries of nucleotide excision repair and transcription-coupled repair led by Phil Hanawalt and a few colleagues sparked a dramatic evolution in our understanding of DNA and molecular biology by revealing the intriguing systems of DNA repair essential to life. In fact, modifications of the cut-and-patch principles identified by Phil Hanawalt and colleagues underlie many of the common themes for the recognition and removal of damaged DNA bases outlined in this review. The emergence of these common themes and a unified understanding have been greatly aided from the direct visualizations of repair proteins and their interactions with damaged DNA by structural biology. These visualizations of DNA repair structures have complemented the increasing wealth of biochemical and genetic information on DNA base damage responses by revealing general themes for the recognition of damaged bases, such as sequence-independent DNA recognition motifs, minor groove reading heads for initial damage recognition, and nucleotide flipping from the major groove into active-site pockets for high specificity of base damage recognition and removal. We know that repair intermediates are as harmful as the initial damage itself, and that these intermediates are protected from one repair step to the next by the enzymes involved, such that pathway-specific handoffs must be efficiently coordinated. Here we focus on the structural biology of the repair enzymes and proteins that recognize specific base lesions and either initiate the base excision repair pathway or directly repair the damage in one step. This understanding of the molecular basis for DNA base integrity is fundamental to resolving key scientific, medical, and public health issues, including the evaluation of the risks from inherited repair protein mutations, environmental toxins, and medical procedures.
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Affiliation(s)
- Joy L Huffman
- Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd., La Jolla, CA 92037, USA
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