1
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Zhang L, Duan HC, Paduch M, Hu J, Zhang C, Mu Y, Lin H, He C, Kossiakoff AA, Jia G, Zhang L. The Molecular Basis of Human ALKBH3 Mediated RNA N 1 -methyladenosine (m 1 A) Demethylation. Angew Chem Int Ed Engl 2024; 63:e202313900. [PMID: 38158383 DOI: 10.1002/anie.202313900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 12/17/2023] [Accepted: 12/27/2023] [Indexed: 01/03/2024]
Abstract
N1 -methyladenosine (m1 A) is a prevalent post-transcriptional RNA modification, and the distribution and dynamics of the modification play key epitranscriptomic roles in cell development. At present, the human AlkB Fe(II)/α-ketoglutarate-dependent dioxygenase family member ALKBH3 is the only known mRNA m1 A demethylase, but its catalytic mechanism remains unclear. Here, we present the structures of ALKBH3-oligo crosslinked complexes obtained with the assistance of a synthetic antibody crystallization chaperone. Structural and biochemical results showed that ALKBH3 utilized two β-hairpins (β4-loop-β5 and β'-loop-β'') and the α2 helix to facilitate single-stranded substrate binding. Moreover, a bubble-like region around Asp194 and a key residue inside the active pocket (Thr133) enabled specific recognition and demethylation of m1 A- and 3-methylcytidine (m3 C)-modified substrates. Mutation of Thr133 to the corresponding residue in the AlkB Fe(II)/α-ketoglutarate-dependent dioxygenase family members FTO or ALKBH5 converted ALKBH3 substrate selectivity from m1 A to N6 -methyladenosine (m6 A), as did Asp194 deletion. Our findings provide a molecular basis for understanding the mechanisms of substrate recognition and m1 A demethylation by ALKBH3. This study is expected to aid structure-guided design of chemical probes for further functional studies and therapeutic applications.
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Affiliation(s)
- Lin Zhang
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Hong-Chao Duan
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Marcin Paduch
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
| | - Jingyan Hu
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Chi Zhang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Yajuan Mu
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Houwen Lin
- Research Centre for Marine Drugs, State Key Laboratory of Oncogene and Related Genes, Department of Pharmacy, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200127, China
- Institute of Marine Biomedicine, Shenzhen Polytechnic, Shenzhen, 518055, China
| | - Chuan He
- Department of Chemistry and Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
- Howard Hughes Medical Institute, University of Chicago, Chicago, IL, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Anthony A Kossiakoff
- Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Guifang Jia
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
- Peking-Tsinghua Center for Life Sciences, Beijing, 100871, China
| | - Liang Zhang
- Department of Pharmacology and Chemical Biology, State Key Laboratory of Systems Medicine for Cancer, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
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Kanazhevskaya LY, Gorbunov AA, Lukina MV, Smyshliaev DA, Zhdanova PV, Lomzov AA, Koval VV. The Role of Key Amino Acids of the Human Fe(II)/2OG-Dependent Dioxygenase ALKBH3 in Structural Dynamics and Repair Activity toward Methylated DNA. Int J Mol Sci 2024; 25:1145. [PMID: 38256217 PMCID: PMC10816986 DOI: 10.3390/ijms25021145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/13/2024] [Accepted: 01/16/2024] [Indexed: 01/24/2024] Open
Abstract
Non-heme dioxygenases of the AlkB family hold a unique position among enzymes that repair alkyl lesions in nucleic acids. These enzymes activate the Fe(II) ion and molecular oxygen through the coupled decarboxylation of the 2-oxoglutarate co-substrate to subsequently oxidize the substrate. ALKBH3 is a human homolog of E. coli AlkB, which displays a specific activity toward N1-methyladenine and N3-methylcytosine bases in single-stranded DNA. Due to the lack of a DNA-bound structure of ALKBH3, the basis of its substrate specificity and structure-function relationships requires further exploration. Here we have combined biochemical and biophysical approaches with site-directed mutational analysis to elucidate the role of key amino acids in maintaining the secondary structure and catalytic activity of ALKBH3. Using stopped-flow fluorescence spectroscopy we have shown that conformational dynamics play a crucial role in the catalytic repair process catalyzed by ALKBH3. A transient kinetic mechanism, which comprises the steps of the specific substrate binding, eversion, and anchoring within the DNA-binding cleft, has been described quantitatively by rate and equilibrium constants. Through CD spectroscopy, we demonstrated that replacing side chains of Tyr143, Leu177, and His191 with alanine results in significant alterations in the secondary structure content of ALKBH3 and decreases the stability of mutant proteins. The bulky side chain of Tyr143 is critical for binding the methylated base and stabilizing its flipped-out conformation, while its hydroxyl group is likely involved in facilitating the product release. The removal of the Leu177 and His191 side chains substantially affects the secondary structure content and conformational flexibility, leading to the complete inactivation of the protein. The mutants lacking enzymatic activity exhibit a marked decrease in antiparallel β-strands, offset by an increase in the helical component.
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Affiliation(s)
- Lyubov Yu. Kanazhevskaya
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Alexey A. Gorbunov
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova St., Novosibirsk 630090, Russia
| | - Maria V. Lukina
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova St., Novosibirsk 630090, Russia
| | - Denis A. Smyshliaev
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova St., Novosibirsk 630090, Russia
| | - Polina V. Zhdanova
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova St., Novosibirsk 630090, Russia
| | - Alexander A. Lomzov
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova St., Novosibirsk 630090, Russia
| | - Vladimir V. Koval
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), 8 Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova St., Novosibirsk 630090, Russia
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3
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Shang G, Yang M, Li M, Ma L, Liu Y, Ma J, Chen Y, Wang X, Fan S, Xie M, Wu W, Dai S, Chen Z. Structural Basis of Nucleic Acid Recognition and 6mA Demethylation by Caenorhabditis elegans NMAD-1A. Int J Mol Sci 2024; 25:686. [PMID: 38255759 PMCID: PMC10815869 DOI: 10.3390/ijms25020686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 12/30/2023] [Accepted: 12/31/2023] [Indexed: 01/24/2024] Open
Abstract
N6-methyladenine (6mA) of DNA is an emerging epigenetic mark in the genomes of Chlamydomonas, Caenorhabditis elegans, and mammals recently. Levels of 6mA undergo drastic fluctuation and thus affect fertility during meiosis and early embryogenesis. Here, we showed three complex structures of 6mA demethylase C. elegans NMAD-1A, a canonical isoform of NMAD-1 (F09F7.7). Biochemical results revealed that NMAD-1A prefers 6mA Bubble or Bulge DNAs. Structural studies of NMAD-1A revealed an unexpected "stretch-out" conformation of its Flip2 region, a conserved element that is usually bent over the catalytic center to facilitate substrate base flipping in other DNA demethylases. Moreover, the wide channel between the Flip1 and Flip2 of the NMAD-1A explained the observed preference of NMAD-1A for unpairing substrates, of which the flipped 6mA was primed for catalysis. Structural analysis and mutagenesis studies confirmed that key elements such as carboxy-terminal domain (CTD) and hypothetical zinc finger domain (ZFD) critically contributed to structural integrity, catalytic activity, and nucleosome binding. Collectively, our biochemical and structural studies suggest that NMAD-1A prefers to regulate 6mA in the unpairing regions and is thus possibly associated with dynamic chromosome regulation and meiosis regulation.
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Affiliation(s)
- Guohui Shang
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Meiting Yang
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Min Li
- National Protein Science Facility, Tsinghua University, Beijing 100084, China
| | - Lulu Ma
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yunlong Liu
- School of Life Sciences, Tiangong University, Tianjin 300387, China
| | - Jun Ma
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yiyun Chen
- Department of Biochemistry, University of Colorado, Boulder, CO 80303, USA
| | - Xue Wang
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shilong Fan
- National Protein Science Facility, Tsinghua University, Beijing 100084, China
| | - Mengjia Xie
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Wei Wu
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Shaodong Dai
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Zhongzhou Chen
- State Key Laboratory of Animal Biotech Breeding and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China
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Li Q, Qian W, Zhang Y, Hu L, Chen S, Xia Y. A new wave of innovations within the DNA damage response. Signal Transduct Target Ther 2023; 8:338. [PMID: 37679326 PMCID: PMC10485079 DOI: 10.1038/s41392-023-01548-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 06/01/2023] [Accepted: 06/27/2023] [Indexed: 09/09/2023] Open
Abstract
Genome instability has been identified as one of the enabling hallmarks in cancer. DNA damage response (DDR) network is responsible for maintenance of genome integrity in cells. As cancer cells frequently carry DDR gene deficiencies or suffer from replicative stress, targeting DDR processes could induce excessive DNA damages (or unrepaired DNA) that eventually lead to cell death. Poly (ADP-ribose) polymerase (PARP) inhibitors have brought impressive benefit to patients with breast cancer gene (BRCA) mutation or homologous recombination deficiency (HRD), which proves the concept of synthetic lethality in cancer treatment. Moreover, the other two scenarios of DDR inhibitor application, replication stress and combination with chemo- or radio- therapy, are under active clinical exploration. In this review, we revisited the progress of DDR targeting therapy beyond the launched first-generation PARP inhibitors. Next generation PARP1 selective inhibitors, which could maintain the efficacy while mitigating side effects, may diversify the application scenarios of PARP inhibitor in clinic. Albeit with unavoidable on-mechanism toxicities, several small molecules targeting DNA damage checkpoints (gatekeepers) have shown great promise in preliminary clinical results, which may warrant further evaluations. In addition, inhibitors for other DNA repair pathways (caretakers) are also under active preclinical or clinical development. With these progresses and efforts, we envision that a new wave of innovations within DDR has come of age.
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Affiliation(s)
- Qi Li
- Domestic Discovery Service Unit, WuXi AppTec, 200131, Shanghai, China
| | - Wenyuan Qian
- Domestic Discovery Service Unit, WuXi AppTec, 200131, Shanghai, China
| | - Yang Zhang
- Domestic Discovery Service Unit, WuXi AppTec, 200131, Shanghai, China
| | - Lihong Hu
- Domestic Discovery Service Unit, WuXi AppTec, 200131, Shanghai, China
| | - Shuhui Chen
- Domestic Discovery Service Unit, WuXi AppTec, 200131, Shanghai, China
| | - Yuanfeng Xia
- Domestic Discovery Service Unit, WuXi AppTec, 200131, Shanghai, China.
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Yin L, Shi K, Aihara H. Structural basis of sequence-specific cytosine deamination by double-stranded DNA deaminase toxin DddA. Nat Struct Mol Biol 2023; 30:1153-1159. [PMID: 37460895 PMCID: PMC10442228 DOI: 10.1038/s41594-023-01034-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 06/12/2023] [Indexed: 07/21/2023]
Abstract
The interbacterial deaminase toxin DddA catalyzes cytosine-to-uracil conversion in double-stranded (ds) DNA and enables CRISPR-free mitochondrial base editing, but the molecular mechanisms underlying its unique substrate selectivity have remained elusive. Here, we report crystal structures of DddA bound to a dsDNA substrate containing the 5'-TC target motif. These structures show that DddA binds to the minor groove of a sharply bent dsDNA and engages the target cytosine extruded from the double helix. DddA Phe1375 intercalates in dsDNA and displaces the 5' (-1) thymine, which in turn replaces the target (0) cytosine and forms a noncanonical T-G base pair with the juxtaposed guanine. This tandem displacement mechanism allows DddA to locate a target cytosine without flipping it into the active site. Biochemical experiments demonstrate that DNA base mismatches enhance the DddA deaminase activity and relax its sequence selectivity. On the basis of the structural information, we further identified DddA mutants that exhibit attenuated activity or altered substrate preference. Our studies may help design new tools useful in genome editing or other applications.
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Affiliation(s)
- Lulu Yin
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Ke Shi
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA
| | - Hideki Aihara
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, USA.
- Institute for Molecular Virology, University of Minnesota, Minneapolis, MN, USA.
- Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA.
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6
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Davletgildeeva AT, Tyugashev TE, Zhao M, Kuznetsov NA, Ishchenko AA, Saparbaev M, Kuznetsova AA. Individual Contributions of Amido Acid Residues Tyr122, Ile168, and Asp173 to the Activity and Substrate Specificity of Human DNA Dioxygenase ABH2. Cells 2023; 12:1839. [PMID: 37508504 PMCID: PMC10377887 DOI: 10.3390/cells12141839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 06/29/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
Human Fe(II)/α-ketoglutarate-dependent dioxygenase ABH2 plays a crucial role in the direct reversal repair of nonbulky alkyl lesions in DNA nucleobases, e.g., N1-methyladenine (m1A), N3-methylcytosine (m3C), and some etheno derivatives. Moreover, ABH2 is capable of a less efficient oxidation of an epigenetic DNA mark called 5-methylcytosine (m5C), which typically is a specific target of DNA dioxygenases from the TET family. In this study, to elucidate the mechanism of the substrate specificity of ABH2, we investigated the role of several active-site amino acid residues. Functional mapping of the lesion-binding pocket was performed through the analysis of the functions of Tyr122, Ile168, and Asp173 in the damaged base recognition mechanism. Interactions of wild-type ABH2, or its mutants Y122A, I168A, or D173A, with damaged DNA containing the methylated base m1A or m3C or the epigenetic marker m5C were analyzed by molecular dynamics simulations and kinetic assays. Comparative analysis of the enzymes revealed an effect of the substitutions on DNA binding and on catalytic activity. Obtained data clearly demonstrate the effect of the tested amino acid residues on the catalytic activity of the enzymes rather than the DNA-binding ability. Taken together, these data shed light on the molecular and kinetic consequences of the substitution of active-site residues for the mechanism of the substrate recognition.
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Affiliation(s)
- Anastasiia T Davletgildeeva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Timofey E Tyugashev
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - Mingxing Zhao
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Alexander A Ishchenko
- Groupe Mechanisms of DNA Repair and Carcinogenesis, CNRS UMR9019, Gustave Roussy Cancer Campus, Université Paris-Saclay, CEDEX, F-94805 Villejuif, France
| | - Murat Saparbaev
- Groupe Mechanisms of DNA Repair and Carcinogenesis, CNRS UMR9019, Gustave Roussy Cancer Campus, Université Paris-Saclay, CEDEX, F-94805 Villejuif, France
| | - Aleksandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia
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Peng Z, Ma J, Christov CZ, Karabencheva-Christova T, Lehnert N, Li D. Kinetic Studies on the 2-Oxoglutarate/Fe(II)-Dependent Nucleic Acid Modifying Enzymes from the AlkB and TET Families. DNA 2023; 3:65-84. [PMID: 38698914 PMCID: PMC11065319 DOI: 10.3390/dna3020005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Nucleic acid methylations are important genetic and epigenetic biomarkers. The formation and removal of these markers is related to either methylation or demethylation. In this review, we focus on the demethylation or oxidative modification that is mediated by the 2-oxoglutarate (2-OG)/Fe(II)-dependent AlkB/TET family enzymes. In the catalytic process, most enzymes oxidize 2-OG to succinate, in the meantime oxidizing methyl to hydroxymethyl, leaving formaldehyde and generating demethylated base. The AlkB enzyme from Escherichia coli has nine human homologs (ALKBH1-8 and FTO) and the TET family includes three members, TET1 to 3. Among them, some enzymes have been carefully studied, but for certain enzymes, few studies have been carried out. This review focuses on the kinetic properties of those 2-OG/Fe(II)-dependent enzymes and their alkyl substrates. We also provide some discussions on the future directions of this field.
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Affiliation(s)
- Zhiyuan Peng
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Jian Ma
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Christo Z. Christov
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA
| | | | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
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Li Q, Zhu Q. The role of demethylase AlkB homologs in cancer. Front Oncol 2023; 13:1153463. [PMID: 37007161 PMCID: PMC10060643 DOI: 10.3389/fonc.2023.1153463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 03/03/2023] [Indexed: 03/18/2023] Open
Abstract
The AlkB family (ALKBH1-8 and FTO), a member of the Fe (II)- and α-ketoglutarate-dependent dioxygenase superfamily, has shown the ability to catalyze the demethylation of a variety of substrates, including DNA, RNA, and histones. Methylation is one of the natural organisms’ most prevalent forms of epigenetic modifications. Methylation and demethylation processes on genetic material regulate gene transcription and expression. A wide variety of enzymes are involved in these processes. The methylation levels of DNA, RNA, and histones are highly conserved. Stable methylation levels at different stages can coordinate the regulation of gene expression, DNA repair, and DNA replication. Dynamic methylation changes are essential for the abilities of cell growth, differentiation, and division. In some malignancies, the methylation of DNA, RNA, and histones is frequently altered. To date, nine AlkB homologs as demethylases have been identified in numerous cancers’ biological processes. In this review, we summarize the latest advances in the research of the structures, enzymatic activities, and substrates of the AlkB homologs and the role of these nine homologs as demethylases in cancer genesis, progression, metastasis, and invasion. We provide some new directions for the AlkB homologs in cancer research. In addition, the AlkB family is expected to be a new target for tumor diagnosis and treatment.
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Affiliation(s)
- Qiao Li
- Department of Orthopedic Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
- Department of Spine Surgery, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Qingsan Zhu
- Department of Orthopedic Surgery, China-Japan Union Hospital of Jilin University, Changchun, Jilin, China
- *Correspondence: Qingsan Zhu,
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Conformational Dynamics of Human ALKBH2 Dioxygenase in the Course of DNA Repair as Revealed by Stopped-Flow Fluorescence Spectroscopy. Molecules 2022; 27:molecules27154960. [PMID: 35956910 PMCID: PMC9370705 DOI: 10.3390/molecules27154960] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 11/30/2022] Open
Abstract
Elucidation of physicochemical mechanisms of enzymatic processes is one of the main tasks of modern biology. High efficiency and selectivity of enzymatic catalysis are mostly ensured by conformational dynamics of enzymes and substrates. Here, we applied a stopped-flow kinetic analysis based on fluorescent spectroscopy to investigate mechanisms of conformational transformations during the removal of alkylated bases from DNA by ALKBH2, a human homolog of Escherichia coli AlkB dioxygenase. This enzyme protects genomic DNA against various alkyl lesions through a sophisticated catalytic mechanism supported by a cofactor (Fe(II)), a cosubstrate (2-oxoglutarate), and O2. We present here a comparative study of conformational dynamics in complexes of the ALKBH2 protein with double-stranded DNA substrates containing N1-methyladenine, N3-methylcytosine, or 1,N6-ethenoadenine. By means of fluorescent labels of different types, simultaneous detection of conformational transitions in the protein globule and DNA substrate molecule was performed. Fitting of the kinetic curves by a nonlinear-regression method yielded a molecular mechanism and rate constants of its individual steps. The results shed light on overall conformational dynamics of ALKBH2 and damaged DNA during the catalytic cycle.
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10
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Tan T, Li Y, Tang B, Chen Y, Chen X, Xie Q, Hu Z, Chen G. Knockout of SlALKBH2 weakens the DNA damage repair ability of tomato. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2022; 319:111266. [PMID: 35487670 DOI: 10.1016/j.plantsci.2022.111266] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/01/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
During the growth and evolution of plants, genomic DNA is subject to constant assault from endogenous and environmental DNA damage compounds, which will result in mutagenic or genotoxic covalent adducts. Whether for prokaryotes, eukaryotes or even viruses, maintaining genome integrity is critical for the continuation of life. Escherichia coli and mammals have evolved the AlkB family of Fe(II)/alpha-ketoglutarate-dependent dioxygenases that repair DNA alkylation damage. We identified a functional homologue with EsAlkB and HsALKBH2 in tomatoes, and named it SlALKBH2. In our study, the SlALKBH2 knockout mutant showed hypersensitivity to the DNA mutagen MMS and displayed more severe growth abnormalities than wild-type plants under mutagen treatment, such as slow growth, leaf deformation and early senescence. Additionally, genes with high transcriptional activity, such as rDNA, have increased methylation under MMS treatment. In conclusion, this study shows that the tomato SlALKBH2 gene may play an important role in ensuring the integrity of the genome.
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Affiliation(s)
- Tingting Tan
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China
| | - Yangyang Li
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China
| | - Boyan Tang
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China
| | - Yating Chen
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China
| | - Xinru Chen
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China
| | - Qiaoli Xie
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China
| | - Zongli Hu
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China.
| | - Guoping Chen
- Laboratory of Molecular Biology of Tomato, Bioengineering College, Chongqing University, Chongqing, People's Republic of China.
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11
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Shaji UP, Tuti N, Das S, Anindya R, Mohan M. Interactions between HIV protease inhibitor ritonavir and human DNA repair enzyme ALKBH2: a molecular dynamics simulation study. Mol Divers 2022; 27:931-938. [PMID: 35543797 DOI: 10.1007/s11030-022-10444-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 04/12/2022] [Indexed: 11/24/2022]
Abstract
The human DNA repair enzyme AlkB homologue-2 (ALKBH2) repairs methyl adducts from genomic DNA. Overexpression of ALKBH2 has been implicated in both tumorigenesis and chemotherapy resistance in some cancers, including glioblastoma and renal cancer rendering it a potential therapeutic target and a diagnostic marker. However, no inhibitor is available against these important DNA repair proteins. Intending to repurpose a drug as an inhibitor of ALKBH2, we performed in silico evaluation of HIV protease inhibitors and identified Ritonavir as an ALKBH2-interacting molecule. Using molecular dynamics simulation, we elucidated the molecular details of Ritonavir-ALKBH2 interaction. The present work highlights that Ritonavir might be used to target the ALKBH2-mediated DNA alkylation repair.
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Affiliation(s)
| | - Nikhil Tuti
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi Sanga Reddy, Telangana, 502284, India
| | - Susmita Das
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi Sanga Reddy, Telangana, 502284, India
| | - Roy Anindya
- Department of Biotechnology, Indian Institute of Technology Hyderabad, Kandi Sanga Reddy, Telangana, 502284, India.
| | - Monisha Mohan
- Department of Science and Humanities, Indian Institute of Information Technology Design and Manufacturing Kancheepuram, Chennai, Tamilnadu, 600127, India.
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12
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Kaur S, Tam NY, McDonough MA, Schofield CJ, Aik W. Mechanisms of substrate recognition and N6-methyladenosine demethylation revealed by crystal structures of ALKBH5-RNA complexes. Nucleic Acids Res 2022; 50:4148-4160. [PMID: 35333330 PMCID: PMC9023255 DOI: 10.1093/nar/gkac195] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/10/2022] [Accepted: 03/14/2022] [Indexed: 01/12/2023] Open
Abstract
AlkB homologue 5 (ALKBH5) is a ferrous iron and 2-oxoglutarate dependent oxygenase that demethylates RNA N6-methyladenosine (m6A), a post-transcriptional RNA modification with an emerging set of regulatory roles. Along with the fat mass and obesity-associated protein (FTO), ALKBH5 is one of only two identified human m6A RNA oxidizing enzymes and is a potential target for cancer treatment. Unlike FTO, ALKBH5 efficiently catalyzes fragmentation of its proposed nascent hemiaminal intermediate to give formaldehyde and a demethylated nucleoside. A detailed analysis of the molecular mechanisms used by ALKBH5 for substrate recognition and m6A demethylation is lacking. We report three crystal structures of ALKBH5 in complex with an m6A-ssRNA 8-mer substrate and supporting biochemical analyses. Strikingly, the single-stranded RNA substrate binds to the active site of ALKBH5 in a 5'-3' orientation that is opposite to single-stranded or double-stranded DNA substrates observed for other AlkB subfamily members, including single-stranded DNA bound to FTO. The combined structural and biochemical results provide insight into the preference of ALKBH5 for substrates containing a (A/G)m6AC consensus sequence motif. The results support a mechanism involving formation of an m6A hemiaminal intermediate, followed by efficient ALKBH5 catalyzed demethylation, enabled by a proton shuttle network involving Lys132 and Tyr139.
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Affiliation(s)
- Simranjeet Kaur
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
| | - Nok Yin Tam
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
| | - Michael A McDonough
- The Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Christopher J Schofield
- The Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Wei Shen Aik
- Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China
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13
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Ma L, Lu H, Tian Z, Yang M, Ma J, Shang G, Liu Y, Xie M, Wang G, Wu W, Zhang Z, Dai S, Chen Z. Structural insights into the interactions and epigenetic functions of human nucleic acid repair protein ALKBH6. J Biol Chem 2022; 298:101671. [PMID: 35120926 PMCID: PMC8892091 DOI: 10.1016/j.jbc.2022.101671] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 12/03/2022] Open
Abstract
Human AlkB homolog 6, ALKBH6, plays key roles in nucleic acid damage repair and tumor therapy. However, no precise structural and functional information are available for this protein. In this study, we determined atomic resolution crystal structures of human holo-ALKBH6 and its complex with ligands. AlkB members bind nucleic acids by NRLs (nucleotide recognition lids, also called Flips), which can recognize DNA/RNA and flip methylated lesions. We found that ALKBH6 has unusual Flip1 and Flip2 domains, distinct from other AlkB family members both in sequence and conformation. Moreover, we show that its unique Flip3 domain has multiple unreported functions, such as discriminating against double-stranded nucleic acids, blocking the active center, binding other proteins, and in suppressing tumor growth. Structural analyses and substrate screening reveal how ALKBH6 discriminates between different types of nucleic acids and may also function as a nucleic acid demethylase. Structure-based interacting partner screening not only uncovered an unidentified interaction of transcription repressor ZMYND11 and ALKBH6 in tumor suppression but also revealed cross talk between histone modification and nucleic acid modification in epigenetic regulation. Taken together, these results shed light on the molecular mechanism underlying ALKBH6-associated nucleic acid damage repair and tumor therapy.
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Affiliation(s)
- Lulu Ma
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Hongyun Lu
- School of food and health, Beijing Technology and Business University, No. 11, Fucheng Road, Haidian District, Beijing, 100048, China
| | - Zizi Tian
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Meiting Yang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jun Ma
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Guohui Shang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yunlong Liu
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Mengjia Xie
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Guoguo Wang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Wei Wu
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Ziding Zhang
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Shaodong Dai
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, United States
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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14
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A novel inhibitor of N 6-methyladenosine demethylase FTO induces mRNA methylation and shows anti-cancer activities. Acta Pharm Sin B 2022; 12:853-866. [PMID: 35256950 PMCID: PMC8897214 DOI: 10.1016/j.apsb.2021.08.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/19/2021] [Accepted: 08/24/2021] [Indexed: 11/26/2022] Open
Abstract
N6-methyladenosine (m6A) modification is critical for mRNA splicing, nuclear export, stability and translation. Fat mass and obesity-associated protein (FTO), the first identified m6A demethylase, is critical for cancer progression. Herein, we developed small-molecule inhibitors of FTO by virtual screening, structural optimization, and bioassay. As a result, two FTO inhibitors namely 18077 and 18097 were identified, which can selectively inhibit demethylase activity of FTO. Specifically, 18097 bound to the active site of FTO and then inhibited cell cycle process and migration of cancer cells. In addition, 18097 reprogrammed the epi-transcriptome of breast cancer cells, particularly for genes related to P53 pathway. 18097 increased the abundance of m6A modification of suppressor of cytokine signaling 1 (SOCS1) mRNA, which recruited IGF2BP1 to increase mRNA stability of SOCS1 and subsequently activated the P53 signaling pathway. Further, 18097 suppressed cellular lipogenesis via downregulation of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), and C/EBPβ. Animal studies confirmed that 18097 can significantly suppress in vivo growth and lung colonization of breast cancer cells. Collectively, we identified that FTO can work as a potential drug target and the small-molecule inhibitor 18097 can serve as a potential agent against breast cancer.
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15
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Schmidl D, Jonasson NSW, Menke A, Schneider S, Daumann L. Spectroscopic and in vitro investigations of Fe2+/α-Ketoglutarate-dependent enzymes involved in nucleic acid repair and modification. Chembiochem 2022; 23:e202100605. [PMID: 35040547 PMCID: PMC9401043 DOI: 10.1002/cbic.202100605] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/14/2022] [Indexed: 11/08/2022]
Abstract
The activation of molecular oxygen for the highly selective functionalization and repair of DNA and RNA nucleobases is achieved by α-ketoglutarate (α-KG)/iron-dependent dioxygenases. Enzymes of special interest are the human homologs AlkBH of Escherichia coli EcAlkB and ten-eleven translocation (TET) enzymes. These enzymes are involved in demethylation or dealkylation of DNA and RNA, although additional physiological functions are continuously being revealed. Given their importance, studying enzyme-substrate interactions, turnover and kinetic parameters is pivotal for the understanding of the mode of action of these enzymes. Diverse analytical methods, including X-ray crystallography, UV/Vis absorption, electron paramagnetic resonance (EPR), circular dichroism (CD) and NMR spectroscopy have been employed to study the changes in the active site and the overall enzyme structure upon substrate, cofactor and inhibitor addition. Several methods are now available to assess activity of these enzymes. By discussing limitations and possibilities of these techniques for EcAlkB, AlkBH and TET we aim to give a comprehensive synopsis from a bioinorganic point of view, addressing researchers from different disciplines working in the highly interdisciplinary and rapidly evolving field of epigenetic processes and DNA/RNA repair and modification.
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Affiliation(s)
- David Schmidl
- Ludwig-Maximilians-Universität München: Ludwig-Maximilians-Universitat Munchen, Chemistry, GERMANY
| | - Niko S W Jonasson
- Ludwig-Maximilians-Universität München: Ludwig-Maximilians-Universitat Munchen, Chemistry, GERMANY
| | - Annika Menke
- Ludwig-Maximilians-Universität München: Ludwig-Maximilians-Universitat Munchen, Chemistry, GERMANY
| | - Sabine Schneider
- Ludwig-Maximilians-Universität München: Ludwig-Maximilians-Universitat Munchen, Chemistry, GERMANY
| | - Lena Daumann
- Ludwig-Maximilians-Universität München, Department of Chemistry, Butenandtstr. 5-13, 81377, München, GERMANY
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16
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O’Brown ZK, Greer EL. N6-methyladenine: A Rare and Dynamic DNA Mark. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:177-210. [DOI: 10.1007/978-3-031-11454-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Structure and Function of TET Enzymes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:239-267. [DOI: 10.1007/978-3-031-11454-0_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Vincent MS, Uphoff S. Cellular heterogeneity in DNA alkylation repair increases population genetic plasticity. Nucleic Acids Res 2021; 49:12320-12331. [PMID: 34850170 PMCID: PMC8643705 DOI: 10.1093/nar/gkab1143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/27/2021] [Accepted: 11/03/2021] [Indexed: 11/29/2022] Open
Abstract
DNA repair mechanisms fulfil a dual role, as they are essential for cell survival and genome maintenance. Here, we studied how cells regulate the interplay between DNA repair and mutation. We focused on the adaptive response that increases the resistance of Escherichia coli cells to DNA alkylation damage. Combination of single-molecule imaging and microfluidic-based single-cell microscopy showed that noise in the gene activation timing of the master regulator Ada is accurately propagated to generate a distinct subpopulation of cells in which all proteins of the adaptive response are essentially absent. Whereas genetic deletion of these proteins causes extreme sensitivity to alkylation stress, a temporary lack of expression is tolerated and increases genetic plasticity of the whole population. We demonstrated this by monitoring the dynamics of nascent DNA mismatches during alkylation stress as well as the frequency of fixed mutations that are generated by the distinct subpopulations of the adaptive response. We propose that stochastic modulation of DNA repair capacity by the adaptive response creates a viable hypermutable subpopulation of cells that acts as a source of genetic diversity in a clonal population.
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Affiliation(s)
- Maxence S Vincent
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Stephan Uphoff
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
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19
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Perry GS, Das M, Woon ECY. Inhibition of AlkB Nucleic Acid Demethylases: Promising New Epigenetic Targets. J Med Chem 2021; 64:16974-17003. [PMID: 34792334 DOI: 10.1021/acs.jmedchem.1c01694] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The AlkB family of nucleic acid demethylases is currently of intense chemical, biological, and medical interest because of its critical roles in several key cellular processes, including epigenetic gene regulation, RNA metabolism, and DNA repair. Emerging evidence suggests that dysregulation of AlkB demethylases may underlie the pathogenesis of several human diseases, particularly obesity, diabetes, and cancer. Hence there is strong interest in developing selective inhibitors for these enzymes to facilitate their mechanistic and functional studies and to validate their therapeutic potential. Herein we review the remarkable advances made over the past 20 years in AlkB demethylase inhibition research. We discuss the rational design of reported inhibitors, their mode-of-binding, selectivity, cellular activity, and therapeutic opportunities. We further discuss unexplored structural elements of the AlkB subfamilies and propose potential strategies to enable subfamily selectivity. It is hoped that this perspective will inspire novel inhibitor design and advance drug discovery research in this field.
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Affiliation(s)
- Gemma S Perry
- School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom
| | - Mohua Das
- Lab of Precision Oncology and Cancer Evolution, Genome Institute of Singapore, 60 Biopolis Street, Singapore 138672, Singapore
| | - Esther C Y Woon
- School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom
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20
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Berger MB, Walker AR, Vázquez-Montelongo EA, Cisneros GA. Computational investigations of selected enzymes from two iron and α-ketoglutarate-dependent families. Phys Chem Chem Phys 2021; 23:22227-22240. [PMID: 34586107 PMCID: PMC8516722 DOI: 10.1039/d1cp03800a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
DNA alkylation is used as the key epigenetic mark in eukaryotes, however, most alkylation in DNA can result in deleterious effects. Therefore, this process needs to be tightly regulated. The enzymes of the AlkB and Ten-Eleven Translocation (TET) families are members of the Fe and alpha-ketoglutarate-dependent superfamily of enzymes that are tasked with dealkylating DNA and RNA in cells. Members of these families span all species and are an integral part of transcriptional regulation. While both families catalyze oxidative dealkylation of various bases, each has specific preference for alkylated base type as well as distinct catalytic mechanisms. This perspective aims to provide an overview of computational work carried out to investigate several members of these enzyme families including AlkB, ALKB Homolog 2, ALKB Homolog 3 and Ten-Eleven Translocate 2. Insights into structural details, mutagenesis studies, reaction path analysis, electronic structure features in the active site, and substrate preferences are presented and discussed.
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Affiliation(s)
- Madison B Berger
- Department of Chemistry, University of North Texas, Denton, Texas, 76201, USA.
| | - Alice R Walker
- Department of Chemistry, Wayne State University, Detroit, Michigan, 48202, USA
| | | | - G Andrés Cisneros
- Department of Chemistry, University of North Texas, Denton, Texas, 76201, USA.
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21
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Zhou LL, Xu H, Huang Y, Yang CG. Targeting the RNA demethylase FTO for cancer therapy. RSC Chem Biol 2021; 2:1352-1369. [PMID: 34704042 PMCID: PMC8496078 DOI: 10.1039/d1cb00075f] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 07/26/2021] [Indexed: 01/02/2023] Open
Abstract
N 6-Methyladenosine (m6A) is the most prevalent internal modification on mRNA and represents a new layer of gene expression in eukaryotes. The field of m6A-encoded epitranscriptomics was rejuvenated with the discovery of fat mass and obesity-associated protein (FTO) as the first m6A demethylase responsible for RNA modification in cells. Increasing evidence has revealed that FTO is significantly involved in physiological processes, and its dysregulation is implicated in various human diseases. Considering this functional significance, developing small-molecule modulators of the FTO protein represents a novel direction for biology research. However, such modulators remain in the early stages of development. Here, our review mainly focuses on the progress of FTO inhibitor development to date. We summarize screening methods used to identify FTO modulators, techniques used to assess the biological effects of these modulators, strategies used to achieve selective inhibition of FTO rather than its homologues, and the results of investigations of FTO modulator modes of action and anticancer efficacy. Thus, this review aims to facilitate novel chemical entity discovery, probe FTO biology, and promote the validation of FTO as a clinical drug target for cancer treatment.
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Affiliation(s)
- Lin-Lin Zhou
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- University of the Chinese Academy of Sciences Beijing 100049 China
| | - Hongjiao Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- University of the Chinese Academy of Sciences Beijing 100049 China
| | - Yue Huang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences Hangzhou 310024 China
| | - Cai-Guang Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- University of the Chinese Academy of Sciences Beijing 100049 China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences Hangzhou 310024 China
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22
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DNA Demethylation in the Processes of Repair and Epigenetic Regulation Performed by 2-Ketoglutarate-Dependent DNA Dioxygenases. Int J Mol Sci 2021; 22:ijms221910540. [PMID: 34638881 PMCID: PMC8508711 DOI: 10.3390/ijms221910540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 09/26/2021] [Accepted: 09/27/2021] [Indexed: 12/05/2022] Open
Abstract
Site-specific DNA methylation plays an important role in epigenetic regulation of gene expression. Chemical methylation of DNA, including the formation of various methylated nitrogenous bases, leads to the formation of genotoxic modifications that impair DNA functions. Despite the fact that different pathways give rise to methyl groups in DNA, the main pathway for their removal is oxidative demethylation, which is catalyzed by nonheme Fe(II)/α-ketoglutarate–dependent DNA dioxygenases. DNA dioxygenases share a common catalytic mechanism of the oxidation of the alkyl groups on nitrogenous bases in nucleic acids. This review presents generalized data on the catalytic mechanism of action of DNA dioxygenases and on the participation of typical representatives of this superfamily, such as prokaryotic enzyme AlkB and eukaryotic enzymes ALKBH1–8 and TET1–3, in both processes of direct repair of alkylated DNA adducts and in the removal of an epigenetic mark (5-methylcytosine).
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23
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Rabe P, Kamps JJAG, Sutherlin KD, Linyard JDS, Aller P, Pham CC, Makita H, Clifton I, McDonough MA, Leissing TM, Shutin D, Lang PA, Butryn A, Brem J, Gul S, Fuller FD, Kim IS, Cheah MH, Fransson T, Bhowmick A, Young ID, O'Riordan L, Brewster AS, Pettinati I, Doyle M, Joti Y, Owada S, Tono K, Batyuk A, Hunter MS, Alonso-Mori R, Bergmann U, Owen RL, Sauter NK, Claridge TDW, Robinson CV, Yachandra VK, Yano J, Kern JF, Orville AM, Schofield CJ. X-ray free-electron laser studies reveal correlated motion during isopenicillin N synthase catalysis. SCIENCE ADVANCES 2021; 7:eabh0250. [PMID: 34417180 PMCID: PMC8378823 DOI: 10.1126/sciadv.abh0250] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/29/2021] [Indexed: 05/23/2023]
Abstract
Isopenicillin N synthase (IPNS) catalyzes the unique reaction of l-δ-(α-aminoadipoyl)-l-cysteinyl-d-valine (ACV) with dioxygen giving isopenicillin N (IPN), the precursor of all natural penicillins and cephalosporins. X-ray free-electron laser studies including time-resolved crystallography and emission spectroscopy reveal how reaction of IPNS:Fe(II):ACV with dioxygen to yield an Fe(III) superoxide causes differences in active site volume and unexpected conformational changes that propagate to structurally remote regions. Combined with solution studies, the results reveal the importance of protein dynamics in regulating intermediate conformations during conversion of ACV to IPN. The results have implications for catalysis by multiple IPNS-related oxygenases, including those involved in the human hypoxic response, and highlight the power of serial femtosecond crystallography to provide insight into long-range enzyme dynamics during reactions presently impossible for nonprotein catalysts.
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Affiliation(s)
- Patrick Rabe
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Jos J A G Kamps
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
| | - Kyle D Sutherlin
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - James D S Linyard
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Pierre Aller
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
| | - Cindy C Pham
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Hiroki Makita
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Ian Clifton
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Michael A McDonough
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Thomas M Leissing
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Denis Shutin
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Pauline A Lang
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Agata Butryn
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
| | - Jürgen Brem
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Sheraz Gul
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Franklin D Fuller
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - In-Sik Kim
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Mun Hon Cheah
- Department of Chemistry - Ångström, Molecular Biomimetics, Uppsala University, SE 751 20 Uppsala, Sweden
| | - Thomas Fransson
- Interdisciplinary Center for Scientific Computing, University of Heidelberg, 69120 Heidelberg, Germany
| | - Asmit Bhowmick
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Iris D Young
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, 600 16th Street, San Francisco, CA 94158, USA
| | - Lee O'Riordan
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Aaron S Brewster
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Ilaria Pettinati
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Margaret Doyle
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Yasumasa Joti
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Shigeki Owada
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Alexander Batyuk
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Mark S Hunter
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Roberto Alonso-Mori
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Uwe Bergmann
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706, USA
| | - Robin L Owen
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK
| | - Nicholas K Sauter
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Timothy D W Claridge
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Carol V Robinson
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
| | - Vittal K Yachandra
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
| | - Jan F Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA.
| | - Allen M Orville
- Diamond Light Source, Diamond House, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, Oxfordshire OX11 0FA, UK
| | - Christopher J Schofield
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute for Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK.
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24
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Zhang LS, Xiong QP, Perez SP, Liu C, Wei J, Le C, Zhang L, Harada BT, Dai Q, Feng X, Hao Z, Wang Y, Dong X, Hu L, Wang ED, Pan T, Klungland A, Liu RJ, He C. ALKBH7-mediated demethylation regulates mitochondrial polycistronic RNA processing. Nat Cell Biol 2021; 23:684-691. [PMID: 34253897 PMCID: PMC8716185 DOI: 10.1038/s41556-021-00709-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 06/07/2021] [Indexed: 02/06/2023]
Abstract
Members of the mammalian AlkB family are known to mediate nucleic acid demethylation1,2. ALKBH7, a mammalian AlkB homologue, localizes in mitochondria and affects metabolism3, but its function and mechanism of action are unknown. Here we report an approach to site-specifically detect N1-methyladenosine (m1A), N3-methylcytidine (m3C), N1-methylguanosine (m1G) and N2,N2-dimethylguanosine (m22G) modifications simultaneously within all cellular RNAs, and discovered that human ALKBH7 demethylates m22G and m1A within mitochondrial Ile and Leu1 pre-tRNA regions, respectively, in nascent polycistronic mitochondrial RNA4-6. We further show that ALKBH7 regulates the processing and structural dynamics of polycistronic mitochondrial RNAs. Depletion of ALKBH7 leads to increased polycistronic mitochondrial RNA processing, reduced steady-state mitochondria-encoded tRNA levels and protein translation, and notably decreased mitochondrial activity. Thus, we identify ALKBH7 as an RNA demethylase that controls nascent mitochondrial RNA processing and mitochondrial activity.
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Affiliation(s)
- Li-Sheng Zhang
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Qing-Ping Xiong
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, PR China
| | - Sonia Peña Perez
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Chang Liu
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Jiangbo Wei
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Cassy Le
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| | - Linda Zhang
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Bryan T. Harada
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Qing Dai
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Xinran Feng
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Ziyang Hao
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Yuru Wang
- Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
| | - Xueyang Dong
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Lulu Hu
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - En-Duo Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, PR China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, PR China
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
| | - Arne Klungland
- Department of Microbiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.,Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Ru-Juan Liu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, PR China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, PR China
| | - Chuan He
- Department of Chemistry, The University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA.,Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
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25
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Raina A, Sahu PK, Laskar RA, Rajora N, Sao R, Khan S, Ganai RA. Mechanisms of Genome Maintenance in Plants: Playing It Safe With Breaks and Bumps. Front Genet 2021; 12:675686. [PMID: 34239541 PMCID: PMC8258418 DOI: 10.3389/fgene.2021.675686] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/04/2021] [Indexed: 01/14/2023] Open
Abstract
Maintenance of genomic integrity is critical for the perpetuation of all forms of life including humans. Living organisms are constantly exposed to stress from internal metabolic processes and external environmental sources causing damage to the DNA, thereby promoting genomic instability. To counter the deleterious effects of genomic instability, organisms have evolved general and specific DNA damage repair (DDR) pathways that act either independently or mutually to repair the DNA damage. The mechanisms by which various DNA repair pathways are activated have been fairly investigated in model organisms including bacteria, fungi, and mammals; however, very little is known regarding how plants sense and repair DNA damage. Plants being sessile are innately exposed to a wide range of DNA-damaging agents both from biotic and abiotic sources such as ultraviolet rays or metabolic by-products. To escape their harmful effects, plants also harbor highly conserved DDR pathways that share several components with the DDR machinery of other organisms. Maintenance of genomic integrity is key for plant survival due to lack of reserve germline as the derivation of the new plant occurs from the meristem. Untowardly, the accumulation of mutations in the meristem will result in a wide range of genetic abnormalities in new plants affecting plant growth development and crop yield. In this review, we will discuss various DNA repair pathways in plants and describe how the deficiency of each repair pathway affects plant growth and development.
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Affiliation(s)
- Aamir Raina
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
- Botany Section, Women’s College, Aligarh Muslim University, Aligarh, India
| | - Parmeshwar K. Sahu
- Department of Genetics and Plant Breeding, Indira Gandhi Agriculture University, Raipur, India
| | | | - Nitika Rajora
- National Agri-Food Biotechnology Institute, Mohali, India
| | - Richa Sao
- Department of Genetics and Plant Breeding, Indira Gandhi Agriculture University, Raipur, India
| | - Samiullah Khan
- Mutation Breeding Laboratory, Department of Botany, Aligarh Muslim University, Aligarh, India
| | - Rais A. Ganai
- Watson-Crick Centre for Molecular Medicine, Islamic University of Science and Technology, Awantipora, India
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26
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Zhang X, Wang D, Elberse J, Qi L, Shi W, Peng YL, Schuurink RC, Van den Ackerveken G, Liu J. Structure-guided analysis of Arabidopsis JASMONATE-INDUCED OXYGENASE (JOX) 2 reveals key residues for recognition of jasmonic acid substrate by plant JOXs. MOLECULAR PLANT 2021; 14:820-828. [PMID: 33516967 DOI: 10.1016/j.molp.2021.01.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 12/20/2020] [Accepted: 01/22/2021] [Indexed: 05/06/2023]
Abstract
The jasmonic acid (JA) signaling pathway is used by plants to control wound responses. The persistent accumulation of JA inhibits plant growth, and the hydroxylation of JA to 12-hydroxy-JA by JASMONATE-INDUCED OXYGENASEs (JOXs, also named jasmonic acid oxidases) is therefore vital for plant growth, while structural details of JA recognition by JOXs are unknown. Here, we present the 2.65 Å resolution X-ray crystal structure of Arabidopsis JOX2 in complex with its substrate JA and its co-substrates 2-oxoglutarate and Fe(II). JOX2 contains a distorted double-stranded β helix (DSBH) core flanked by α helices and loops. JA is bound in the narrow substrate pocket by hydrogen bonds with the arginine triad R225, R350, and R354 and by hydrophobic interactions mainly with the phenylalanine triad F157, F317, and F346. The most critical residues for JA binding are F157 and R225, both from the DSBH core, which interact with the cyclopentane ring of JA. The spatial distribution of critical residues for JA binding and the shape of the substrate-binding pocket together define the substrate selectivity of the JOXs. Sequence alignment shows that these critical residues are conserved among JOXs from higher plants. Collectively, our study provides insights into the mechanism by which higher plants hydroxylate the hormone JA.
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Affiliation(s)
- Xin Zhang
- State Key Laboratory of Agrobiotechnology, Ministry of Agriculture Key Laboratory for Crop Pest Monitoring and Green Control, Joint International Research Laboratory of Crop Molecular Breeding, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Dongli Wang
- State Key Laboratory of Agrobiotechnology, Ministry of Agriculture Key Laboratory for Crop Pest Monitoring and Green Control, Joint International Research Laboratory of Crop Molecular Breeding, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Joyce Elberse
- Plant-Microbe Interactions, Department of Biology, Utrecht University, 3508 TB Utrecht, the Netherlands
| | - Linlu Qi
- State Key Laboratory of Agrobiotechnology, Ministry of Agriculture Key Laboratory for Crop Pest Monitoring and Green Control, Joint International Research Laboratory of Crop Molecular Breeding, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Wei Shi
- State Key Laboratory of Agrobiotechnology, Ministry of Agriculture Key Laboratory for Crop Pest Monitoring and Green Control, Joint International Research Laboratory of Crop Molecular Breeding, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - You-Liang Peng
- State Key Laboratory of Agrobiotechnology, Ministry of Agriculture Key Laboratory for Crop Pest Monitoring and Green Control, Joint International Research Laboratory of Crop Molecular Breeding, College of Plant Protection, China Agricultural University, Beijing 100193, China
| | - Robert C Schuurink
- Green Life Sciences Research Cluster, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Guido Van den Ackerveken
- Plant-Microbe Interactions, Department of Biology, Utrecht University, 3508 TB Utrecht, the Netherlands.
| | - Junfeng Liu
- State Key Laboratory of Agrobiotechnology, Ministry of Agriculture Key Laboratory for Crop Pest Monitoring and Green Control, Joint International Research Laboratory of Crop Molecular Breeding, College of Plant Protection, China Agricultural University, Beijing 100193, China.
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27
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Marcinkowski M, Pilžys T, Garbicz D, Piwowarski J, Mielecki D, Nowaczyk G, Taube M, Gielnik M, Kozak M, Winiewska-Szajewska M, Szołajska E, Dębski J, Maciejewska AM, Przygońska K, Ferenc K, Grzesiuk E, Poznański J. Effect of Posttranslational Modifications on the Structure and Activity of FTO Demethylase. Int J Mol Sci 2021; 22:ijms22094512. [PMID: 33925955 PMCID: PMC8123419 DOI: 10.3390/ijms22094512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/19/2021] [Accepted: 04/22/2021] [Indexed: 12/13/2022] Open
Abstract
The FTO protein is involved in a wide range of physiological processes, including adipogenesis and osteogenesis. This two-domain protein belongs to the AlkB family of 2-oxoglutarate (2-OG)- and Fe(II)-dependent dioxygenases, displaying N6-methyladenosine (N6-meA) demethylase activity. The aim of the study was to characterize the relationships between the structure and activity of FTO. The effect of cofactors (Fe2+/Mn2+ and 2-OG), Ca2+ that do not bind at the catalytic site, and protein concentration on FTO properties expressed in either E. coli (ECFTO) or baculovirus (BESFTO) system were determined using biophysical methods (DSF, MST, SAXS) and biochemical techniques (size-exclusion chromatography, enzymatic assay). We found that BESFTO carries three phosphoserines (S184, S256, S260), while there were no such modifications in ECFTO. The S256D mutation mimicking the S256 phosphorylation moderately decreased FTO catalytic activity. In the presence of Ca2+, a slight stabilization of the FTO structure was observed, accompanied by a decrease in catalytic activity. Size exclusion chromatography and MST data confirmed the ability of FTO from both expression systems to form homodimers. The MST-determined dissociation constant of the FTO homodimer was consistent with their in vivo formation in human cells. Finally, a low-resolution structure of the FTO homodimer was built based on SAXS data.
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Affiliation(s)
- Michał Marcinkowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Tomaš Pilžys
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Damian Garbicz
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Jan Piwowarski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Damian Mielecki
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Grzegorz Nowaczyk
- NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614 Poznan, Poland;
| | - Michał Taube
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznanskiego 2, 61-614 Poznan, Poland; (M.T.); (M.G.); (M.K.)
| | - Maciej Gielnik
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznanskiego 2, 61-614 Poznan, Poland; (M.T.); (M.G.); (M.K.)
| | - Maciej Kozak
- Department of Macromolecular Physics, Faculty of Physics, Adam Mickiewicz University, Uniwersytetu Poznanskiego 2, 61-614 Poznan, Poland; (M.T.); (M.G.); (M.K.)
- National Synchrotron Radiation Centre SOLARIS, Jagiellonian University, Czerwone Maki 98, 30-392 Kraków, Poland
| | - Maria Winiewska-Szajewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Ewa Szołajska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Janusz Dębski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Agnieszka M. Maciejewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Kaja Przygońska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
| | - Karolina Ferenc
- Veterinary Research Centre, Department of Large Animal Diseases and Clinic, Institute of Veterinary Medicine, Warsaw University of Life Sciences, Nowoursynowska 100, 02-797 Warsaw, Poland;
| | - Elżbieta Grzesiuk
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
- Correspondence: (E.G.); (J.P.)
| | - Jarosław Poznański
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland; (M.M.); (T.P.); (D.G.); (J.P.); (D.M.); (M.W.-S.); (E.S.); (J.D.); (A.M.M.); (K.P.)
- Correspondence: (E.G.); (J.P.)
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28
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Zhao S, Devega R, Francois A, Kidane D. Human ALKBH6 Is Required for Maintenance of Genomic Stability and Promoting Cell Survival During Exposure of Alkylating Agents in Pancreatic Cancer. Front Genet 2021; 12:635808. [PMID: 33897761 PMCID: PMC8058185 DOI: 10.3389/fgene.2021.635808] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/08/2021] [Indexed: 12/21/2022] Open
Abstract
Alpha-ketoglutarate-dependent dioxygenase (ALKBH) is a DNA repair gene involved in the repair of alkylating DNA damage. There are nine types of ALKBH (ALKBH1-8 and FTO) identified in humans. In particular, certain types of ALKBH enzymes are dioxygenases that directly reverse DNA methylation damage via transfer of a methyl group from the DNA adduct onto α-ketoglutarate and release of metabolic products including succinate and formaldehyde. Here, we tested whether ALKBH6 plays a significant role in preventing alkylating DNA damage and decreasing genomic instability in pancreatic cancer cells. Using an E. coli strain deficient with ALKB, we found that ALKBH6 complements ALKB deficiency and increases resistance after alkylating agent treatment. In particular, the loss of ALKBH6 in human pancreatic cancer cells increases alkylating agent-induced DNA damage and significantly decreases cell survival. Furthermore, in silico analysis from The Cancer Genome Atlas (TCGA) database suggests that overexpression of ALKBH6 provides better survival outcomes in patients with pancreatic cancer. Overall, our data suggest that ALKBH6 is required to maintain the integrity of the genome and promote cell survival of pancreatic cancer cells.
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Affiliation(s)
- Shengyuan Zhao
- Division of Pharmacology and Toxicology, College of Pharmacy, Dell Pediatric Research Institute, The University of Texas at Austin, Austin, TX, United States
| | - Rodan Devega
- Division of Pharmacology and Toxicology, College of Pharmacy, Dell Pediatric Research Institute, The University of Texas at Austin, Austin, TX, United States
| | - Aaliyah Francois
- Division of Pharmacology and Toxicology, College of Pharmacy, Dell Pediatric Research Institute, The University of Texas at Austin, Austin, TX, United States
| | - Dawit Kidane
- Division of Pharmacology and Toxicology, College of Pharmacy, Dell Pediatric Research Institute, The University of Texas at Austin, Austin, TX, United States
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29
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Wang Y, Katanski CD, Watkins C, Pan JN, Dai Q, Jiang Z, Pan T. A high-throughput screening method for evolving a demethylase enzyme with improved and new functionalities. Nucleic Acids Res 2021; 49:e30. [PMID: 33337498 PMCID: PMC7968990 DOI: 10.1093/nar/gkaa1213] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/25/2020] [Accepted: 11/30/2020] [Indexed: 01/26/2023] Open
Abstract
AlkB is a DNA/RNA repair enzyme that removes base alkylations such as N1-methyladenosine (m1A) or N3-methylcytosine (m3C) from DNA and RNA. The AlkB enzyme has been used as a critical tool to facilitate tRNA sequencing and identification of mRNA modifications. As a tool, AlkB mutants with better reactivity and new functionalities are highly desired; however, previous identification of such AlkB mutants was based on the classical approach of targeted mutagenesis. Here, we introduce a high-throughput screening method to evaluate libraries of AlkB variants for demethylation activity on RNA and DNA substrates. This method is based on a fluorogenic RNA aptamer with an internal modified RNA/DNA residue which can block reverse transcription or introduce mutations leading to loss of fluorescence inherent in the cDNA product. Demethylation by an AlkB variant eliminates the blockage or mutation thereby restores the fluorescence signals. We applied our screening method to sites D135 and R210 in the Escherichia coli AlkB protein and identified a variant with improved activity beyond a previously known hyperactive mutant toward N1-methylguanosine (m1G) in RNA. We also applied our method to O6-methylguanosine (O6mG) modified DNA substrates and identified candidate AlkB variants with demethylating activity. Our study provides a high-throughput screening method for in vitro evolution of any demethylase enzyme.
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Affiliation(s)
- Yuru Wang
- Department of Biochemistry and Molecular Biology, USA.,Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | | | | | - Jessica N Pan
- Department of Biochemistry and Molecular Biology, USA
| | - Qing Dai
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Zhuoxun Jiang
- Department of Biochemistry and Molecular Biology, USA
| | - Tao Pan
- Department of Biochemistry and Molecular Biology, USA
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30
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Levintov L, Paul S, Vashisth H. Reaction Coordinate and Thermodynamics of Base Flipping in RNA. J Chem Theory Comput 2021; 17:1914-1921. [PMID: 33594886 DOI: 10.1021/acs.jctc.0c01199] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Base flipping is a key biophysical event involved in recognition of various ligands by ribonucleic acid (RNA) molecules. However, the mechanism of base flipping in RNA remains poorly understood, in part due to the lack of atomistic details on complex rearrangements in neighboring bases. In this work, we applied transition path sampling (TPS) methods to study base flipping in a double-stranded RNA (dsRNA) molecule that is known to interact with RNA-editing enzymes through this mechanism. We obtained an ensemble of 1000 transition trajectories to describe the base-flipping process. We used the likelihood maximization method to determine the refined reaction coordinate (RC) consisting of two collective variables (CVs), a distance and a dihedral angle between nucleotides that form stacking interactions with the flipping base. The free energy profile projected along the refined RC revealed three minima, two corresponding to the initial and final states and one for a metastable state. We suggest that the metastable state likely represents a wobbled conformation of nucleobases observed in NMR studies that is often characterized as the flipped state. The analyses of reactive trajectories further revealed that the base flipping is coupled to a global conformational change in a stem-loop of dsRNA.
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Affiliation(s)
- Lev Levintov
- Department of Chemical Engineering, University of New Hampshire, Durham 03824, New Hampshire, United States
| | - Sanjib Paul
- Department of Chemistry, New York University, New York 10003, New York, United States
| | - Harish Vashisth
- Department of Chemical Engineering, University of New Hampshire, Durham 03824, New Hampshire, United States
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31
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Bayoumi M, Munir M. Structural Insights Into m6A-Erasers: A Step Toward Understanding Molecule Specificity and Potential Antiviral Targeting. Front Cell Dev Biol 2021; 8:587108. [PMID: 33511112 PMCID: PMC7835257 DOI: 10.3389/fcell.2020.587108] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 11/26/2020] [Indexed: 12/13/2022] Open
Abstract
The cellular RNA can acquire a variety of chemical modifications during the cell cycle, and compelling pieces of evidence highlight the importance of these modifications in determining the metabolism of RNA and, subsequently, cell physiology. Among myriads of modifications, methylation at the N6-position of adenosine (m6A) is the most important and abundant internal modification in the messenger RNA. The m6A marks are installed by methyltransferase complex proteins (writers) in the majority of eukaryotes and dynamically reversed by demethylases such as FTO and ALKBH5 (erasers). The incorporated m6A marks on the RNA transcripts are recognized by m6A-binding proteins collectively called readers. Recent epigenetic studies have unequivocally highlighted the association of m6A demethylases with a range of biomedical aspects, including human diseases, cancers, and metabolic disorders. Moreover, the mechanisms of demethylation by m6A erasers represent a new frontier in the future basic research on RNA biology. In this review, we focused on recent advances describing various physiological, pathological, and viral regulatory roles of m6A erasers. Additionally, we aim to analyze structural insights into well-known m6A-demethylases in assessing their substrate binding-specificity, efficiency, and selectivity. Knowledge on cellular and viral RNA metabolism will shed light on m6A-specific recognition by demethylases and will provide foundations for the future development of efficacious therapeutic agents to various cancerous conditions and open new avenues for the development of antivirals.
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Affiliation(s)
- Mahmoud Bayoumi
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom.,Virology Department, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt
| | - Muhammad Munir
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
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32
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Xu B, Liu D, Wang Z, Tian R, Zuo Y. Multi-substrate selectivity based on key loops and non-homologous domains: new insight into ALKBH family. Cell Mol Life Sci 2021; 78:129-141. [PMID: 32642789 PMCID: PMC11072825 DOI: 10.1007/s00018-020-03594-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/24/2020] [Accepted: 07/03/2020] [Indexed: 12/16/2022]
Abstract
AlkB homologs (ALKBH) are a family of specific demethylases that depend on Fe2+ and α-ketoglutarate to catalyze demethylation on different substrates, including ssDNA, dsDNA, mRNA, tRNA, and proteins. Previous studies have made great progress in determining the sequence, structure, and molecular mechanism of the ALKBH family. Here, we first review the multi-substrate selectivity of the ALKBH demethylase family from the perspective of sequence and structural evolution. The construction of the phylogenetic tree and the comparison of key loops and non-homologous domains indicate that the paralogs with close evolutionary relationship have similar domain compositions. The structures show that the lack and variations of four key loops change the shape of clefts to cause the differences in substrate affinity, and non-homologous domains may be related to the compatibility of multiple substrates. We anticipate that the new insights into selectivity determinants of the ALKBH family are useful for understanding the demethylation mechanisms.
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Affiliation(s)
- Baofang Xu
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Sciences, Inner Mongolia University, Hohhot, 010070, China
| | - Dongyang Liu
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Sciences, Inner Mongolia University, Hohhot, 010070, China
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zerong Wang
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Sciences, Inner Mongolia University, Hohhot, 010070, China
| | - Ruixia Tian
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Sciences, Inner Mongolia University, Hohhot, 010070, China
| | - Yongchun Zuo
- The State Key Laboratory of Reproductive Regulation and Breeding of Grassland Livestock, College of Life Sciences, Inner Mongolia University, Hohhot, 010070, China.
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Oxidative demethylase ALKBH5 repairs DNA alkylation damage and protects against alkylation-induced toxicity. Biochem Biophys Res Commun 2020; 534:114-120. [PMID: 33321288 DOI: 10.1016/j.bbrc.2020.12.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 12/05/2020] [Indexed: 11/22/2022]
Abstract
DNA integrity is challenged by both exogenous and endogenous alkylating agents. DNA repair proteins such as Escherichia coli AlkB family of enzymes can repair 1-methyladenine and 3-methylcytosine adducts by oxidative demethylation. Human AlkB homologue 5 (ALKBH5) is RNA N6-methyladenine demethylase and not known to be involved in DNA repair. Herein we show that ALKBH5 also has weak DNA repair activity and it can demethylate DNA 3-methylcytosine. The mutation of the amino acid residues involved in demethylation also abolishes the DNA repair activity of ALKBH5. Overexpression of ALKBH5 decreases the 3-methylcytosine level in genomic DNA and reduces the cytotoxic effects of the DNA damaging alkylating agent methyl methanesulfonate. Thus, demethylation by ALKBH5 might play a supporting role in maintaining genome integrity.
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Abstract
Genomic DNA is chemically reactive and therefore susceptible to damage by many exogenous and endogenous sources. Lesions produced from these damaging events can have various mutagenic and genotoxic consequences. This Perspective follows the journey of one particular lesion, 1,N6-ethenoadenine (εA), from its formation to replication and repair, and its role in cancerous tissues and inflammatory diseases. εA is generated by the reaction of adenine (A) with vinyl chloride or lipid peroxidation products. We present the miscoding properties of εA with an emphasis on how bacterial and mammalian cells can process lesions differently, leading to varied mutational spectra. But with information from these assays, we can better understand how the miscoding properties of εA lead to biological consequences and how genomic stability can be maintained via DNA repair mechanisms. We discuss how base excision repair (BER) and direct reversal repair (DRR) can minimize the biological consequences of εA lesions. Kinetic parameters of glycosylases and AlkB family enzymes are described, along with a discussion of the relative contributions of the BER and DRR pathways in the repair of εA. Because eukaryotic DNA is packaged in chromatin, we also discuss the impact of this packaging on BER and DRR, specifically in regards to repair of εA. Studying DNA lesions like εA in this context, from origin to biological implications, can provide crucial information to better understand prevention of mutagenesis and cancer.
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Affiliation(s)
- Katelyn L Rioux
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Van Deuren V, Plessers S, Robben J. Structural determinants of nucleobase modification recognition in the AlkB family of dioxygenases. DNA Repair (Amst) 2020; 96:102995. [PMID: 33069898 DOI: 10.1016/j.dnarep.2020.102995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 01/29/2023]
Abstract
Iron-dependent dioxygenases of the AlkB protein family found in most organisms throughout the tree of life play a major role in oxidative dealkylation processes. Many of these enzymes have attracted the attention of researchers across different fields and have been subjected to thorough biochemical characterization because of their link to human health and disease. For example, several mammalian AlkB homologues are involved in the direct reversal of alkylation damage in DNA, while others have been shown to play a regulatory role in epigenetic or epitranscriptomic nucleic acid methylation or in post-translational modifications such as acetylation of actin filaments. These studies show that that divergence in amino acid sequence and structure leads to different characteristics and substrate specificities. In this review, we aim to summarize current insights in the structural features involved in the substrate selection of AlkB homologues, with focus on nucleic acid interactions.
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Affiliation(s)
- V Van Deuren
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, B-3001, Heverlee, Belgium
| | - S Plessers
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, B-3001, Heverlee, Belgium
| | - J Robben
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G, B-3001, Heverlee, Belgium.
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36
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Distinct RNA N-demethylation pathways catalyzed by nonheme iron ALKBH5 and FTO enzymes enable regulation of formaldehyde release rates. Proc Natl Acad Sci U S A 2020; 117:25284-25292. [PMID: 32989163 DOI: 10.1073/pnas.2007349117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The AlkB family of nonheme Fe(II)/2-oxoglutarate-dependent oxygenases are essential regulators of RNA epigenetics by serving as erasers of one-carbon marks on RNA with release of formaldehyde (FA). Two major human AlkB family members, FTO and ALKBH5, both act as oxidative demethylases of N6-methyladenosine (m6A) but furnish different major products, N6-hydroxymethyladenosine (hm6A) and adenosine (A), respectively. Here we identify foundational mechanistic differences between FTO and ALKBH5 that promote these distinct biochemical outcomes. In contrast to FTO, which follows a traditional oxidative N-demethylation pathway to catalyze conversion of m6A to hm6A with subsequent slow release of A and FA, we find that ALKBH5 catalyzes a direct m6A-to-A transformation with rapid FA release. We identify a catalytic R130/K132/Y139 triad within ALKBH5 that facilitates release of FA via an unprecedented covalent-based demethylation mechanism with direct detection of a covalent intermediate. Importantly, a K132Q mutant furnishes an ALKBH5 enzyme with an m6A demethylation profile that resembles that of FTO, establishing the importance of this residue in the proposed covalent mechanism. Finally, we show that ALKBH5 is an endogenous source of FA in the cell by activity-based sensing of FA fluxes perturbed via ALKBH5 knockdown. This work provides a fundamental biochemical rationale for nonredundant roles of these RNA demethylases beyond different substrate preferences and cellular localization, where m6A demethylation by ALKBH5 versus FTO results in release of FA, an endogenous one-carbon unit but potential genotoxin, at different rates in living systems.
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Lenz SAP, Li D, Wetmore SD. Insights into the Direct Oxidative Repair of Etheno Lesions: MD and QM/MM Study on the Substrate Scope of ALKBH2 and AlkB. DNA Repair (Amst) 2020; 96:102944. [PMID: 33161373 DOI: 10.1016/j.dnarep.2020.102944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/27/2020] [Accepted: 07/30/2020] [Indexed: 01/09/2023]
Abstract
E. coli AlkB and human ALKBH2 belong to the AlkB family enzymes, which contain several α-ketoglutarate (α-KG)/Fe(II)-dependent dioxygenases that repair alkylated DNA. Specifically, the AlkB enzymes catalyze decarboxylation of α-KG to generate a high-valent Fe(IV)-oxo species that oxidizes alkyl groups on DNA adducts. AlkB and ALKBH2 have been reported to differentially repair select etheno adducts, with preferences for 1,N6-ethenoadenine (1,N6-εA) and 3,N4-ethenocytosine (3,N4-εC) over 1,N2-ethenoguanine (1,N2-εG). However, N2,3-ethenoguanine (N2,3-εG), the most common etheno adduct, is not repaired by the AlkB enzymes. Unfortunately, a structural understanding of the differential activity of E. coli AlkB and human ALKBH2 is lacking due to challenges acquiring atomistic details for a range of substrates using experiments. This study uses both molecular dynamics (MD) simulations and ONIOM(QM:MM) calculations to determine how the active site changes upon binding each etheno adduct and characterizes the corresponding catalytic impacts. Our data reveal that the preferred etheno substrates (1,N6-εA and 3,N4-εC) form favorable interactions with catalytic residues that situate the lesion near the Fe(IV)-oxo species and permit efficient oxidation. In contrast, although the damage remains correctly aligned with respect to the Fe(IV)-oxo moiety, repair of 1,N2-εG is mitigated by increased solvation of the active site and a larger distance between Fe(IV)-oxo and the aberrant carbons. Binding of non-substrate N2,3-εG in the active site disrupts key DNA-enzyme interactions, and positions the aberrant carbon atoms even further from the Fe(IV)-oxo species, leading to prohibitively high barriers for oxidative catalysis. Overall, our calculations provide the first structural insight required to rationalize the experimentally-reported substrate specificities of AlkB and ALKBH2 and thereby highlight the roles of several active site residues in the repair of etheno adducts that directly correlates with available experimental data. These proposed catalytic strategies can likely be generalized to other α-KG/Fe(II)-dependent dioxygenases that play similar critical biological roles, including epigenetic and post-translational regulation.
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Affiliation(s)
- Stefan A P Lenz
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI, 02881, USA
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
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The trajectory of intrahelical lesion recognition and extrusion by the human 8-oxoguanine DNA glycosylase. Nat Commun 2020; 11:4437. [PMID: 32895378 PMCID: PMC7477556 DOI: 10.1038/s41467-020-18290-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 08/14/2020] [Indexed: 02/05/2023] Open
Abstract
Efficient search for DNA damage embedded in vast expanses of the DNA genome presents one of the greatest challenges to DNA repair enzymes. We report here crystal structures of human 8-oxoguanine (oxoG) DNA glycosylase, hOGG1, that interact with the DNA containing the damaged base oxoG and the normal base G while they are nested in the DNA helical stack. The structures reveal that hOGG1 engages the DNA using different protein-DNA contacts from those observed in the previously determined lesion recognition complex and other hOGG1-DNA complexes. By applying molecular dynamics simulations, we have determined the pathways taken by the lesion and normal bases when extruded from the DNA helix and their associated free energy profiles. These results reveal how the human oxoG DNA glycosylase hOGG1 locates the lesions inside the DNA helix and facilitates their extrusion for repair. DNA glycosylases are lesion-specific enzymes that recognize specific nucleobase damages and catalyze their excision through cleavage of the glycosidic bond. Here, the authors present the crystal structures of human 8-oxoguanine (oxoG) DNA glycosylase bound to undamaged DNA and to DNA containing an intrahelical oxoG lesion and further analyse these structures with molecular dynamics simulations, which allows them to characterise the base-extrusion pathways.
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Rabe P, Beale JH, Butryn A, Aller P, Dirr A, Lang PA, Axford DN, Carr SB, Leissing TM, McDonough MA, Davy B, Ebrahim A, Orlans J, Storm SLS, Orville AM, Schofield CJ, Owen RL. Anaerobic fixed-target serial crystallography. IUCRJ 2020; 7:901-912. [PMID: 32939282 PMCID: PMC7467159 DOI: 10.1107/s2052252520010374] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 07/27/2020] [Indexed: 05/04/2023]
Abstract
Cryogenic X-ray diffraction is a powerful tool for crystallographic studies on enzymes including oxygenases and oxidases. Amongst the benefits that cryo-conditions (usually employing a nitro-gen cryo-stream at 100 K) enable, is data collection of di-oxy-gen-sensitive samples. Although not strictly anaerobic, at low temperatures the vitreous ice conditions severely restrict O2 diffusion into and/or through the protein crystal. Cryo-conditions limit chemical reactivity, including reactions that require significant conformational changes. By contrast, data collection at room temperature imposes fewer restrictions on diffusion and reactivity; room-temperature serial methods are thus becoming common at synchrotrons and XFELs. However, maintaining an anaerobic environment for di-oxy-gen-dependent enzymes has not been explored for serial room-temperature data collection at synchrotron light sources. This work describes a methodology that employs an adaptation of the 'sheet-on-sheet' sample mount, which is suitable for the low-dose room-temperature data collection of anaerobic samples at synchrotron light sources. The method is characterized by easy sample preparation in an anaerobic glovebox, gentle handling of crystals, low sample consumption and preservation of a localized anaerobic environment over the timescale of the experiment (<5 min). The utility of the method is highlighted by studies with three X-ray-radiation-sensitive Fe(II)-containing model enzymes: the 2-oxoglutarate-dependent l-arginine hy-droxy-lase VioC and the DNA repair enzyme AlkB, as well as the oxidase isopenicillin N synthase (IPNS), which is involved in the biosynthesis of all penicillin and cephalosporin antibiotics.
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Affiliation(s)
- Patrick Rabe
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - John H. Beale
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Agata Butryn
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Pierre Aller
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Anna Dirr
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Pauline A. Lang
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Danny N. Axford
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Stephen B. Carr
- Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot Oxfordshire OX11 0FA, United Kingdom
| | - Thomas M. Leissing
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Michael A. McDonough
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Bradley Davy
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Ali Ebrahim
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, United Kingdom
| | - Julien Orlans
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
- UMR0203, Biologie Fonctionnelle, Insectes et Interactions, Institut National des Sciences Appliquées de Lyon, Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement, University of Lyon, Villeurbanne F-69621, France
| | - Selina L. S. Storm
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Allen M. Orville
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
| | - Christopher J. Schofield
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Robin L. Owen
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom
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Waheed S, Ramanan R, Chaturvedi SS, Lehnert N, Schofield CJ, Christov CZ, Karabencheva-Christova TG. Role of Structural Dynamics in Selectivity and Mechanism of Non-heme Fe(II) and 2-Oxoglutarate-Dependent Oxygenases Involved in DNA Repair. ACS CENTRAL SCIENCE 2020; 6:795-814. [PMID: 32490196 PMCID: PMC7256942 DOI: 10.1021/acscentsci.0c00312] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Indexed: 05/08/2023]
Abstract
AlkB and its human homologue AlkBH2 are Fe(II)- and 2-oxoglutarate (2OG)-dependent oxygenases that repair alkylated DNA bases occurring as a consequence of reactions with mutagenic agents. We used molecular dynamics (MD) and combined quantum mechanics/molecular mechanics (QM/MM) methods to investigate how structural dynamics influences the selectivity and mechanisms of the AlkB- and AlkBH2-catalyzed demethylation of 3-methylcytosine (m3C) in single (ssDNA) and double (dsDNA) stranded DNA. Dynamics studies reveal the importance of the flexibility in both the protein and DNA components in determining the preferences of AlkB for ssDNA and of AlkBH2 for dsDNA. Correlated motions, including of a hydrophobic β-hairpin, are involved in substrate binding in AlkBH2-dsDNA. The calculations reveal that 2OG rearrangement prior to binding of dioxygen to the active site Fe is preferred over a ferryl rearrangement to form a catalytically productive Fe(IV)=O intermediate. Hydrogen atom transfer proceeds via a σ-channel in AlkBH2-dsDNA and AlkB-dsDNA; in AlkB-ssDNA, there is a competition between σ- and π-channels, implying that the nature of the complexed DNA has potential to alter molecular orbital interactions during the substrate oxidation. Our results reveal the importance of the overall protein-DNA complex in determining selectivity and how the nature of the substrate impacts the mechanism.
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Affiliation(s)
- Sodiq
O. Waheed
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Rajeev Ramanan
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Shobhit S. Chaturvedi
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Nicolai Lehnert
- Department
of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Christopher J. Schofield
- The
Chemistry Research Laboratory, The Department of Chemistry, Mansfield
Road, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Christo Z. Christov
- Department
of Chemistry, Michigan Technological University, Houghton, Michigan 49931, United States
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Caffrey PJ, Kher R, Bian K, Li D, Delaney S. Comparison of the Base Excision and Direct Reversal Repair Pathways for Correcting 1, N6-Ethenoadenine in Strongly Positioned Nucleosome Core Particles. Chem Res Toxicol 2020; 33:1888-1896. [PMID: 32293880 PMCID: PMC7374743 DOI: 10.1021/acs.chemrestox.0c00089] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
1,N6-ethenoadenine (εA) is a
mutagenic lesion and biomarker observed in numerous cancerous tissues.
Two pathways are responsible for its repair: base excision repair
(BER) and direct reversal repair (DRR). Alkyladenine DNA glycosylase
(AAG) is the primary enzyme that excises εA in BER, generating
stable intermediates that are processed by downstream enzymes. For
DRR, the Fe(II)/α-ketoglutarate-dependent ALKBH2 enzyme repairs
εA by direct conversion of εA to A. While the molecular
mechanism of each enzyme is well understood on unpackaged duplex DNA,
less is known about their actions on packaged DNA. The nucleosome
core particle (NCP) forms the minimal packaging unit of DNA in eukaryotic
organisms and is composed of 145–147 base pairs wrapped around
a core of eight histone proteins. In this work, we investigated the
activity of AAG and ALKBH2 on εA lesions globally distributed
at positions throughout a strongly positioned NCP. Overall, we examined
the repair of εA at 23 unique locations in packaged DNA. We
observed a strong correlation between rotational positioning of εA
and AAG activity but not ALKBH2 activity. ALKBH2 was more effective
than AAG at repairing occluded εA lesions, but only AAG was
capable of full repair of any εA in the NCP. However, notable
exceptions to these trends were observed, highlighting the complexity
of the NCP as a substrate for DNA repair. Modeling of binding of the
repair enzymes to NCPs revealed that some of these observations can
be explained by steric interference caused by DNA packaging. Specifically,
interactions between ALKBH2 and the histone proteins obstruct binding
to DNA, which leads to diminished activity. Taken together, these
results support in vivo observations of alkylation
damage profiles and contribute to our understanding of mutational
hotspots.
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Affiliation(s)
- Paul J Caffrey
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Raadhika Kher
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Ke Bian
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Sarah Delaney
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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Probing the DNA-binding center of the MutL protein from the Escherichia coli mismatch repair system via crosslinking and Förster resonance energy transfer. Biochimie 2020; 171-172:43-54. [PMID: 32061805 DOI: 10.1016/j.biochi.2020.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/11/2020] [Indexed: 11/23/2022]
Abstract
As no crystal structure of full-size MutL bound to DNA has been obtained up to date, in the present work we used crosslinking and Förster resonance energy transfer (FRET) assays for probing the putative DNA-binding center of MutL from Escherichia coli. Several single-cysteine MutL variants (scMutL) were used for site-specific crosslinking or fluorophore modification. The crosslinking efficiency between scMutL proteins and mismatched DNA modified with thiol-reactive probes correlated with the distances from the Cys residues to the DNA calculated from a model of MutS-MutL-DNA complex. FRET-based investigation of DNA binding with different scMutL variants clearly showed that the highest signals were detected for the variants MutL(T218C) and MutL(A251C) indicating closeness of the positions 218 and 251 to DNA in the MutL-DNA complex. Indeed, the Cys218 and Cys251 of scMutL were crosslinked to the reactive DNA with the highest yield demonstrating their proximity to DNA in the MutL-DNA complex. The presence of MutS increased the yield of conjugate formation between the MutL variants and the modified DNA due to tighter MutL-DNA interactions caused by MutS binding to MutL.
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43
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Mammalian ALKBH1 serves as an N 6-mA demethylase of unpairing DNA. Cell Res 2020; 30:197-210. [PMID: 32051560 PMCID: PMC7054317 DOI: 10.1038/s41422-019-0237-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/30/2019] [Indexed: 01/07/2023] Open
Abstract
N6-methyladenine (N6-mA) of DNA is an emerging epigenetic mark in mammalian genome. Levels of N6-mA undergo drastic fluctuation during early embryogenesis, indicative of active regulation. Here we show that the 2-oxoglutarate-dependent oxygenase ALKBH1 functions as a nuclear eraser of N6-mA in unpairing regions (e.g., SIDD, Stress-Induced DNA Double Helix Destabilization regions) of mammalian genomes. Enzymatic profiling studies revealed that ALKBH1 prefers bubbled or bulged DNAs as substrate, instead of single-stranded (ss-) or double-stranded (ds-) DNAs. Structural studies of ALKBH1 revealed an unexpected "stretch-out" conformation of its "Flip1" motif, a conserved element that usually bends over catalytic center to facilitate substrate base flipping in other DNA demethylases. Thus, lack of a bending "Flip1" explains the observed preference of ALKBH1 for unpairing substrates, in which the flipped N6-mA is primed for catalysis. Co-crystal structural studies of ALKBH1 bound to a 21-mer bulged DNA explained the need of both flanking duplexes and a flipped base for recognition and catalysis. Key elements (e.g., an ALKBH1-specific α1 helix) as well as residues contributing to structural integrity and catalytic activity were validated by structure-based mutagenesis studies. Furthermore, ssDNA-seq and DIP-seq analyses revealed significant co-occurrence of base unpairing regions with N6-mA in mouse genome. Collectively, our biochemical, structural and genomic studies suggest that ALKBH1 is an important DNA demethylase that regulates genome N6-mA turnover of unpairing regions associated with dynamic chromosome regulation.
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44
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Tian LF, Liu YP, Chen L, Tang Q, Wu W, Sun W, Chen Z, Yan XX. Structural basis of nucleic acid recognition and 6mA demethylation by human ALKBH1. Cell Res 2020; 30:272-275. [PMID: 32051559 DOI: 10.1038/s41422-019-0233-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/02/2019] [Indexed: 11/09/2022] Open
Affiliation(s)
- Li-Fei Tian
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.,National Laboratory of Biomacromolecules, Chinese Academy of Sciences (CAS) Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Yan-Ping Liu
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences (CAS) Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Lianqi Chen
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences (CAS) Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.,College of Life Sciences, University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Qun Tang
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences (CAS) Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Wei Wu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China
| | - Wei Sun
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences (CAS) Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.
| | - Xiao-Xue Yan
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences (CAS) Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.
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45
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Kanazhevskaya LY, Smyshlyaev DA, Alekseeva IV, Fedorova OS. Conformational Dynamics of Dioxygenase AlkB and DNA in the Course of Catalytically Active Enzyme–Substrate Complex Formation. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162019060190] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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46
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Koliadenko V, Wilanowski T. Additional functions of selected proteins involved in DNA repair. Free Radic Biol Med 2020; 146:1-15. [PMID: 31639437 DOI: 10.1016/j.freeradbiomed.2019.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 10/16/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022]
Abstract
Protein moonlighting is a phenomenon in which a single polypeptide chain can perform a number of different unrelated functions. Here we present our analysis of moonlighting in the case of selected DNA repair proteins which include G:T mismatch-specific thymine DNA glycosylase (TDG), methyl-CpG-binding domain protein 4 (MBD4), apurinic/apyrimidinic endonuclease 1 (APE1), AlkB homologs, poly (ADP-ribose) polymerase 1 (PARP-1) and single-strand selective monofunctional uracil DNA glycosylase 1 (SMUG1). Most of their additional functions are not accidental and clear patterns are emerging. Participation in RNA metabolism is not surprising as bases occurring in RNA are the same or very similar to those in DNA. Other common additional function involves regulation of transcription. This is not unexpected as these proteins bind to specific DNA regions for DNA repair, hence they can also be recruited to regulate transcription. Participation in demethylation and replication of DNA appears logical as well. Some of the multifunctional DNA repair proteins play major roles in many diseases, including cancer. However, their moonlighting might prove a major difficulty in the development of new therapies because it will not be trivial to target a single protein function without affecting its other functions that are not related to the disease.
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Affiliation(s)
- Vlada Koliadenko
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland
| | - Tomasz Wilanowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Ilji Miecznikowa 1, 02-096, Warsaw, Poland.
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47
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Kanazhevskaya LY, Alekseeva IV, Fedorova OS. A Single-Turnover Kinetic Study of DNA Demethylation Catalyzed by Fe(II)/α-Ketoglutarate-Dependent Dioxygenase AlkB. Molecules 2019; 24:molecules24244576. [PMID: 31847292 PMCID: PMC6943663 DOI: 10.3390/molecules24244576] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 01/31/2023] Open
Abstract
AlkB is a Fe(II)/α-ketoglutarate-dependent dioxygenase that repairs some alkylated bases of DNA and RNA in Escherichia coli. In the course of catalysis, oxidation of a co-substrate (α-ketoglutarate, αKG) leads to the formation of a highly reactive ‘oxyferryl’ enzyme-bound intermediate, Fe(IV) = O, ensuring hydroxylation of the alkyl nucleobase adducts. Previous studies have revealed that AlkB is a flexible protein and can adopt different conformations during interactions with cofactors and DNA. To assess the conformational dynamics of the enzyme in complex with single- or double-stranded DNA in real-time mode, we employed the stopped-flow fluorescence method. N1-Methyladenine (m1A) introduced into a sequence of 15-mer oligonucleotides was chosen as the specific damage. Single-turnover kinetics were monitored by means of intrinsic fluorescence of the protein’s Trp residues, fluorescent base analogue 2-aminopurine (2aPu), and a dye–quencher pair (FAM/BHQ1). For all the fluorescent labels, the fluorescent traces showed several phases of consistent conformational changes, which were assigned to specific steps of the enzymatic process. These data offer an overall picture of the structural dynamics of AlkB and DNA during their interaction.
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Affiliation(s)
| | | | - Olga S. Fedorova
- Correspondence: (L.Y.K.); (O.S.F.); Tel.: +7-(383)-3635175 (O.S.F.)
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48
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Stelling AL, Liu AY, Zeng W, Salinas R, Schumacher MA, Al‐Hashimi HM. Infrared Spectroscopic Observation of a G–C
+
Hoogsteen Base Pair in the DNA:TATA‐Box Binding Protein Complex Under Solution Conditions. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Allison L. Stelling
- Department of BiochemistryDuke University Medical Center Durham NC 27710 USA
| | - Amy Y. Liu
- Department of BiochemistryDuke University Medical Center Durham NC 27710 USA
| | - Wenjie Zeng
- Department of BiochemistryDuke University Medical Center Durham NC 27710 USA
| | - Raul Salinas
- Department of BiochemistryDuke University Medical Center Durham NC 27710 USA
| | - Maria A. Schumacher
- Department of BiochemistryDuke University Medical Center Durham NC 27710 USA
| | - Hashim M. Al‐Hashimi
- Department of BiochemistryDuke University Medical Center Durham NC 27710 USA
- Department of ChemistryDuke University Durham NC 27710 USA
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49
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Rangadurai A, Zhou H, Merriman DK, Meiser N, Liu B, Shi H, Szymanski ES, Al-Hashimi HM. Why are Hoogsteen base pairs energetically disfavored in A-RNA compared to B-DNA? Nucleic Acids Res 2019; 46:11099-11114. [PMID: 30285154 PMCID: PMC6237737 DOI: 10.1093/nar/gky885] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 10/02/2018] [Indexed: 12/15/2022] Open
Abstract
A(syn)-U/T and G(syn)-C+ Hoogsteen (HG) base pairs (bps) are energetically more disfavored relative to Watson–Crick (WC) bps in A-RNA as compared to B-DNA by >1 kcal/mol for reasons that are not fully understood. Here, we used NMR spectroscopy, optical melting experiments, molecular dynamics simulations and modified nucleotides to identify factors that contribute to this destabilization of HG bps in A-RNA. Removing the 2′-hydroxyl at single purine nucleotides in A-RNA duplexes did not stabilize HG bps relative to WC. In contrast, loosening the A-form geometry using a bulge in A-RNA reduced the energy cost of forming HG bps at the flanking sites to B-DNA levels. A structural and thermodynamic analysis of purine-purine HG mismatches reveals that compared to B-DNA, the A-form geometry disfavors syn purines by 1.5–4 kcal/mol due to sugar-backbone rearrangements needed to sterically accommodate the syn base. Based on MD simulations, an additional penalty of 3–4 kcal/mol applies for purine-pyrimidine HG bps due to the higher energetic cost associated with moving the bases to form hydrogen bonds in A-RNA versus B-DNA. These results provide insights into a fundamental difference between A-RNA and B-DNA duplexes with important implications for how they respond to damage and post-transcriptional modifications.
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Affiliation(s)
- Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Huiqing Zhou
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | | | - Nathalie Meiser
- Goethe University, Institute for Organic Chemistry and Chemical Biology, Frankfurt am Main, Germany
| | - Bei Liu
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC, USA
| | - Eric S Szymanski
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.,Department of Chemistry, Duke University, Durham, NC, USA
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50
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Stelling AL, Liu AY, Zeng W, Salinas R, Schumacher MA, Al-Hashimi HM. Infrared Spectroscopic Observation of a G-C + Hoogsteen Base Pair in the DNA:TATA-Box Binding Protein Complex Under Solution Conditions. Angew Chem Int Ed Engl 2019; 58:12010-12013. [PMID: 31268220 DOI: 10.1002/anie.201902693] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 05/24/2019] [Indexed: 12/22/2022]
Abstract
Hoogsteen DNA base pairs (bps) are an alternative base pairing to canonical Watson-Crick bps and are thought to play important biochemical roles. Hoogsteen bps have been reported in a handful of X-ray structures of protein-DNA complexes. However, there are several examples of Hoogsteen bps in crystal structures that form Watson-Crick bps when examined under solution conditions. Furthermore, Hoogsteen bps can sometimes be difficult to resolve in DNA:protein complexes by X-ray crystallography due to ambiguous electron density and by solution-state NMR spectroscopy due to size limitations. Here, using infrared spectroscopy, we report the first direct solution-state observation of a Hoogsteen (G-C+ ) bp in a DNA:protein complex under solution conditions with specific application to DNA-bound TATA-box binding protein. These results support a previous assignment of a G-C+ Hoogsteen bp in the complex, and indicate that Hoogsteen bps do indeed exist under solution conditions in DNA:protein complexes.
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Affiliation(s)
- Allison L Stelling
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA
| | - Amy Y Liu
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA
| | - Wenjie Zeng
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA
| | - Raul Salinas
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA
| | - Maria A Schumacher
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University Medical Center, Durham, NC, 27710, USA.,Department of Chemistry, Duke University, Durham, NC, 27710, USA
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