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Shimizu N, Hamada Y, Morozumi R, Yamamoto J, Iwai S, Sugiyama KI, Ide H, Tsuda M. Repair of topoisomerase 1-induced DNA damage by tyrosyl-DNA phosphodiesterase 2 (TDP2) is dependent on its magnesium binding. J Biol Chem 2023; 299:104988. [PMID: 37392847 PMCID: PMC10407441 DOI: 10.1016/j.jbc.2023.104988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 07/03/2023] Open
Abstract
Topoisomerases are enzymes that relax DNA supercoiling during replication and transcription. Camptothecin, a topoisomerase 1 (TOP1) inhibitor, and its analogs trap TOP1 at the 3'-end of DNA as a DNA-bound intermediate, resulting in DNA damage that can kill cells. Drugs with this mechanism of action are widely used to treat cancers. It has previously been shown that tyrosyl-DNA phosphodiesterase 1 (TDP1) repairs TOP1-induced DNA damage generated by camptothecin. In addition, tyrosyl-DNA phosphodiesterase 2 (TDP2) plays critical roles in repairing topoisomerase 2 (TOP2)-induced DNA damage at the 5'-end of DNA and in promoting the repair of TOP1-induced DNA damage in the absence of TDP1. However, the catalytic mechanism by which TDP2 processes TOP1-induced DNA damage has not been elucidated. In this study, we found that a similar catalytic mechanism underlies the repair of TOP1- and TOP2-induced DNA damage by TDP2, with Mg2+-TDP2 binding playing a role in both repair mechanisms. We show chain-terminating nucleoside analogs are incorporated into DNA at the 3'-end and abort DNA replication to kill cells. Furthermore, we found that Mg2+-TDP2 binding also contributes to the repair of incorporated chain-terminating nucleoside analogs. Overall, these findings reveal the role played by Mg2+-TDP2 binding in the repair of both 3'- and 5'-blocking DNA damage.
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Affiliation(s)
- Naoto Shimizu
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Yusaku Hamada
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Ryosuke Morozumi
- Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| | - Junpei Yamamoto
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Shigenori Iwai
- Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, Japan
| | - Kei-Ichi Sugiyama
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan
| | - Hiroshi Ide
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan.
| | - Masataka Tsuda
- Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan; Program of Biomedical Science, Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan; Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kawasaki, Kanagawa, Japan.
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Crewe M, Madabhushi R. Topoisomerase-Mediated DNA Damage in Neurological Disorders. Front Aging Neurosci 2021; 13:751742. [PMID: 34899270 PMCID: PMC8656403 DOI: 10.3389/fnagi.2021.751742] [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: 08/01/2021] [Accepted: 10/23/2021] [Indexed: 12/12/2022] Open
Abstract
The nervous system is vulnerable to genomic instability and mutations in DNA damage response factors lead to numerous developmental and progressive neurological disorders. Despite this, the sources and mechanisms of DNA damage that are most relevant to the development of neuronal dysfunction are poorly understood. The identification of primarily neurological abnormalities in patients with mutations in TDP1 and TDP2 suggest that topoisomerase-mediated DNA damage could be an important underlying source of neuronal dysfunction. Here we review the potential sources of topoisomerase-induced DNA damage in neurons, describe the cellular mechanisms that have evolved to repair such damage, and discuss the importance of these repair mechanisms for preventing neurological disorders.
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Zhang H, Xiong Y, Chen J. DNA-protein cross-link repair: what do we know now? Cell Biosci 2020; 10:3. [PMID: 31921408 PMCID: PMC6945406 DOI: 10.1186/s13578-019-0366-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 12/13/2019] [Indexed: 12/13/2022] Open
Abstract
When a protein is covalently and irreversibly bound to DNA (i.e., a DNA–protein cross-link [DPC]), it may obstruct any DNA-based transaction, such as transcription and replication. DPC formation is very common in cells, as it can arise from endogenous factors, such as aldehyde produced during cell metabolism, or exogenous sources like ionizing radiation, ultraviolet light, and chemotherapeutic agents. DPCs are composed of DNA, protein, and their cross-linked bonds, each of which can be targeted by different repair pathways. Many studies have demonstrated that nucleotide excision repair and homologous recombination can act on DNA molecules and execute nuclease-dependent DPC repair. Enzymes that have evolved to deal specifically with DPC, such as tyrosyl-DNA phosphodiesterases 1 and 2, can directly reverse cross-linked bonds and release DPC from DNA. The newly identified proteolysis pathway, which employs the proteases Wss1 and SprT-like domain at the N-terminus (SPRTN), can directly hydrolyze the proteins in DPCs, thus offering a new venue for DPC repair in cells. A deep understanding of the mechanisms of each pathway and the interplay among them may provide new guidance for targeting DPC repair as a therapeutic strategy for cancer. Here, we summarize the progress in DPC repair field and describe how cells may employ these different repair pathways for efficient repair of DPCs.
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Affiliation(s)
- Huimin Zhang
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Yun Xiong
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Junjie Chen
- Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX USA
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Laev SS, Salakhutdinov NF, Lavrik OI. Tyrosyl-DNA phosphodiesterase inhibitors: Progress and potential. Bioorg Med Chem 2016; 24:5017-5027. [PMID: 27687971 DOI: 10.1016/j.bmc.2016.09.045] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/30/2016] [Accepted: 09/18/2016] [Indexed: 10/21/2022]
Abstract
DNA topoisomerases are essential during transcription and replication. The therapeutic mechanism of action of topoisomerase inhibitors is enzyme poisoning rather than catalytic inhibition. Tyrosyl-DNA phosphodiesterases 1 or 2 were found as DNA repair enzymes hydrolyzing the covalent bond between the tyrosyl residue of topoisomerases I or II and the 3'- or 5'-phosphate groups in DNA, respectively. Tyrosyl-DNA phosphodiesterase 1 is a key enzyme in DNA repair machinery and a promising target for antitumor and neurodegenerative therapy. Inhibitors of tyrosyl-DNA phosphodiesterase 1 could act synergistically with topoisomerase I inhibitors and thereby potentiate the effects of topoisomerase I poisons. Tyrosyl-DNA phosphodiesterase 2 is an enzyme that specifically repairs DNA damages induced by topoisomerase II poisons and causes resistance to these drugs. Selective inhibition of tyrosyl-DNA phosphodiesterase 2 may be a novel approach to overcome intrinsic or acquired resistance to topoisomerase II-targeted drug therapy. Thus, agents that inhibit tyrosyl-DNA phosphodiesterases 1 and 2 have many applications in biochemical and physiological research and they have the potential to become anticancer and antiviral drugs. The structures, mechanism of action and therapeutic rationale of tyrosyl-DNA phosphodiesterase inhibitors and their development for combinations with topoisomerase inhibitors and DNA damaging agents are discussed.
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Affiliation(s)
- Sergey S Laev
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation.
| | - Nariman F Salakhutdinov
- Vorozhtsov Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 9, Novosibirsk 630090, Russian Federation; Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation
| | - Olga I Lavrik
- Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russian Federation; Novosibirsk Institute of Chemical Biology and Fundamental Medicine, Siberian Division, Russian Academy of Sciences, pr. akademika Lavrent'eva 8, Novosibirsk 630090, Russian Federation
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Depletion of tyrosyl DNA phosphodiesterase 2 activity enhances etoposide-mediated double-strand break formation and cell killing. DNA Repair (Amst) 2016; 43:38-47. [DOI: 10.1016/j.dnarep.2016.04.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 11/20/2022]
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Kemmerich FE, Daldrop P, Pinto C, Levikova M, Cejka P, Seidel R. Force regulated dynamics of RPA on a DNA fork. Nucleic Acids Res 2016; 44:5837-48. [PMID: 27016742 PMCID: PMC4937307 DOI: 10.1093/nar/gkw187] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/04/2016] [Indexed: 01/24/2023] Open
Abstract
Replication protein A (RPA) is a single-stranded DNA binding protein, involved in most aspects of eukaryotic DNA metabolism. Here, we study the behavior of RPA on a DNA substrate that mimics a replication fork. Using magnetic tweezers we show that both yeast and human RPA can open forked DNA when sufficient external tension is applied. In contrast, at low force, RPA becomes rapidly displaced by the rehybridization of the DNA fork. This process appears to be governed by the binding or the release of an RPA microdomain (toehold) of only few base-pairs length. This gives rise to an extremely rapid exchange dynamics of RPA at the fork. Fork rezipping rates reach up to hundreds of base-pairs per second, being orders of magnitude faster than RPA dissociation from ssDNA alone. Additionally, we show that RPA undergoes diffusive motion on ssDNA, such that it can be pushed over long distances by a rezipping fork. Generally the behavior of both human and yeast RPA homologs is very similar. However, in contrast to yeast RPA, the dissociation of human RPA from ssDNA is greatly reduced at low Mg2+ concentrations, such that human RPA can melt DNA in absence of force.
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Affiliation(s)
- Felix E Kemmerich
- Institute of Experimental Physics I, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany Institute for Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster, Germany
| | - Peter Daldrop
- Institute for Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster, Germany
| | - Cosimo Pinto
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Maryna Levikova
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Petr Cejka
- Institute of Molecular Cancer Research, University of Zurich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Ralf Seidel
- Institute of Experimental Physics I, Universität Leipzig, Linnéstr. 5, 04103 Leipzig, Germany Institute for Molecular Cell Biology, University of Münster, Schlossplatz 5, D-48149 Münster, Germany
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Wei J, Zhang P, Guo M, Xu M, Li P, Chen X, Gao P, Yan Y, Wei S, Qin Q. TTRAP is a critical factor in grouper immune response to virus infection. FISH & SHELLFISH IMMUNOLOGY 2015; 46:274-284. [PMID: 26172204 DOI: 10.1016/j.fsi.2015.07.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 07/07/2015] [Accepted: 07/08/2015] [Indexed: 06/04/2023]
Abstract
TTRAP (TRAF and TNF receptor-associated protein) is latest identified cytosolic protein that serves as a negative regulator for TNF signaling pathway. In this study, a member of TNF superfamily, TTRAP gene (designed as EcTTRAP) was cloned from grouper, Epinephelus coioides. There was an Exo_endo_phos type domain in EcTTRAP, and it was well conserved when compared with other TTRAPs, especially the endonuclease activity related motifs. EcTTRAP exhibited prominent endonuclease activity against the genome DNA from Escherichia coli, Vibrio vulnificus and E. coli JM109. Intracellular localization revealed that EcTTRAP expression distributed in both cytoplasm and nucleus. Real-time PCR analysis indicates that EcTTRAP is expressed in all selective grouper tissues, with the higher expression level in muscle, skin and gills. EcTTRAP was identified as a remarkably (P < 0.01) up-regulated protein responding to Singapore grouper iridovirus (SGIV) infection. Overexpression of EcTTRAP inhibited NF-κB activation, meanwhile the C terminal portion of the protein was found to be responsive domain for the inhibition. Stable transfection of FHM cells with EcTTRAP inhibited apoptosis induced by SGIV. Overexpression of EcTTRAP in grouper spleen (GS) cells inhibited the replication of SGIV. The present results provided new evidences for the potential roles of such molecule in E. coioides, and further confirmed the existence of TTRAP modulated TNF signaling pathway in grouper.
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Affiliation(s)
- Jingguang Wei
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China
| | - Ping Zhang
- Teaching Center of Biology Experiment, School of Life Sciences, Sun Yat-sen University, 135West Xingang Road, Guangzhou 510275, PR China
| | - Minglan Guo
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China
| | - Meng Xu
- State Key Laboratory Breeding Base for Sustainable Exploitation of Tropical Biotic Resources, College of Marine Science, Hainan University, Haikou 570228, PR China
| | - Pengfei Li
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China
| | - Xiuli Chen
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China
| | - Pin Gao
- State Key Laboratory Breeding Base for Sustainable Exploitation of Tropical Biotic Resources, College of Marine Science, Hainan University, Haikou 570228, PR China
| | - Yang Yan
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China
| | - Shina Wei
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China
| | - Qiwei Qin
- Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China; Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, PR China.
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Barrera D, Díaz L, Noyola-Martínez N, Halhali A. Vitamin D and Inflammatory Cytokines in Healthy and Preeclamptic Pregnancies. Nutrients 2015; 7:6465-90. [PMID: 26247971 PMCID: PMC4555132 DOI: 10.3390/nu7085293] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 04/28/2015] [Accepted: 07/29/2015] [Indexed: 01/08/2023] Open
Abstract
Preeclampsia is a pregnancy disease characterized by hypertension and proteinuria. Among several disorders, the imbalance of inflammatory cytokines and the alteration of vitamin D metabolism have been reported in preeclampsia. The effects of calcitriol upon inflammatory cytokines has been demonstrated. In healthy pregnant women there is a shift toward a Th2 cytokine profile, which is necessary for an adequate pregnancy outcome. As compared with normal pregnancy, high pro-inflammatory and low anti-inflammatory cytokine levels have been observed in preeclamptic women. Preeclampsia has been associated with low calcitriol levels and vitamin D deficiency is correlated with a higher risk of the development of this disease. It has been demonstrated that placenta is a source as well as the target of calcitriol and cytokines and placental dysfunction has been associated with preeclampsia. Therefore, the present manuscript includes a review about serum calcitriol levels in non-pregnant, pregnant, and preeclamptic women as well as a review on the fetoplacental vitamin D metabolism in healthy and preeclamptic pregnancies. In addition, circulating and fetoplacental inflammatory cytokines in healthy and preeclamptic pregnancies are reviewed. Finally, the effects of calcitriol upon placental pro-inflammatory cytokines are also explored. In conclusion, maternal and placental calcitriol levels are low in preeclampsia which may explain, at least in part, high pro-inflammatory cytokine levels in this disease.
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Affiliation(s)
- David Barrera
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga No. 15, Tlalpan, México D.F. 14000, México.
| | - Lorenza Díaz
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga No. 15, Tlalpan, México D.F. 14000, México.
| | - Nancy Noyola-Martínez
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga No. 15, Tlalpan, México D.F. 14000, México.
| | - Ali Halhali
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga No. 15, Tlalpan, México D.F. 14000, México.
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Abstract
TDP1 and TDP2 were discovered and named based on the fact they process 3'- and 5'-DNA ends by excising irreversible protein tyrosyl-DNA complexes involving topoisomerases I and II, respectively. Yet, both enzymes have an extended spectrum of activities. TDP1 not only excises trapped topoisomerases I (Top1 in the nucleus and Top1mt in mitochondria), but also repairs oxidative damage-induced 3'-phosphoglycolates and alkylation damage-induced DNA breaks, and excises chain terminating anticancer and antiviral nucleosides in the nucleus and mitochondria. The repair function of TDP2 is devoted to the excision of topoisomerase II- and potentially topoisomerases III-DNA adducts. TDP2 is also essential for the life cycle of picornaviruses (important human and bovine pathogens) as it unlinks VPg proteins from the 5'-end of the viral RNA genome. Moreover, TDP2 has been involved in signal transduction (under the former names of TTRAP or EAPII). The DNA repair partners of TDP1 include PARP1, XRCC1, ligase III and PNKP from the base excision repair (BER) pathway. By contrast, TDP2 repair functions are coordinated with Ku and ligase IV in the non-homologous end joining pathway (NHEJ). This article summarizes and compares the biochemistry, functions, and post-translational regulation of TDP1 and TDP2, as well as the relevance of TDP1 and TDP2 as determinants of response to anticancer agents. We discuss the rationale for developing TDP inhibitors for combinations with topoisomerase inhibitors (topotecan, irinotecan, doxorubicin, etoposide, mitoxantrone) and DNA damaging agents (temozolomide, bleomycin, cytarabine, and ionizing radiation), and as novel antiviral agents.
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Affiliation(s)
- Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA.
| | - Shar-yin N Huang
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA
| | - Rui Gao
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA
| | - Benu Brata Das
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA; Laboratory of Molecular Biology, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Junko Murai
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA; Department of Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshidakonoe, Sakyo-ku 606-8501, Japan
| | - Christophe Marchand
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, Building 37, Room 5068, NIH, Bethesda, MD 20892, USA
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Shi K, Kurahashi K, Gao R, Tsutakawa SE, Tainer JA, Pommier Y, Aihara H. Structural basis for recognition of 5'-phosphotyrosine adducts by Tdp2. Nat Struct Mol Biol 2012; 19:1372-7. [PMID: 23104058 PMCID: PMC3515695 DOI: 10.1038/nsmb.2423] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 09/19/2012] [Indexed: 12/28/2022]
Abstract
The DNA-repair enzyme Tdp2 resolves 5'-phosphotyrosyl DNA adducts and mediates resistance to anticancer drugs that target covalent topoisomerase-DNA complexes. Tdp2 also participates in key signaling pathways during development and tumorigenesis and cleaves a protein-RNA linkage during picornavirus replication. The crystal structure of zebrafish Tdp2 bound to DNA reveals a deep, narrow basic groove that selectively accommodates the 5' end of single-stranded DNA in a stretched conformation. The crystal structure of the full-length Caenorhabditis elegans Tdp2 shows that this groove can also accommodate an acidic peptide stretch in vitro, with glutamate and aspartate side chains occupying the DNA backbone phosphate-binding sites. This extensive molecular mimicry suggests a potential mechanism for autoregulation and interaction of Tdp2 with phosphorylated proteins in signaling. Our study provides a framework to interrogate functions of Tdp2 and develop inhibitors for chemotherapeutic and antiviral applications.
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Affiliation(s)
- Ke Shi
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
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Gao R, Huang SYN, Marchand C, Pommier Y. Biochemical characterization of human tyrosyl-DNA phosphodiesterase 2 (TDP2/TTRAP): a Mg(2+)/Mn(2+)-dependent phosphodiesterase specific for the repair of topoisomerase cleavage complexes. J Biol Chem 2012; 287:30842-52. [PMID: 22822062 DOI: 10.1074/jbc.m112.393983] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
TDP2 is a multifunctional enzyme previously known for its role in signal transduction as TRAF and TNF receptor-associated protein (TTRAP) and ETS1-associated protein 2 (EAPII). The gene has recently been renamed TDP2 because it plays a critical role for the repair of topoisomerase II cleavage complexes (Top2cc) and encodes an enzyme that hydrolyzes 5'-tyrosine-DNA adducts that mimic abortive Top2cc. Here we further elucidate the DNA-processing activities of human recombinant TDP2 and its biochemical characteristics. The preferred substrate for TDP2 is single-stranded DNA or duplex DNA with a four-base pair overhang, which is consistent with the known structure of Top2cc or Top3cc. The k(cat)/K(m) of TDP1 and TDP2 was determined. It was found to be 4 × 10(5) s(-1)M(-1) for TDP2 using single-stranded 5'-tyrosyl-DNA. The processing of substrates as short as five nucleotides long suggests that TDP2 can directly bind DNA ends. 5'-Phosphodiesterase activity requires a phosphotyrosyl linkage and tolerates an extended group attached to the tyrosine. TDP2 requires Mg(2+) or Mn(2+) for efficient catalysis but is weakly active with Ca(2+) or Zn(2+). Titration with Ca(2+) demonstrates a two-metal binding site in TDP2. Sequence alignment suggests that TDP2 contains four conserved catalytic motifs shared by Mg(2+)-dependent endonucleases, such as APE1. Substitutions at each of the four catalytic motifs identified key residues Asn-120, Glu-152, Asp-262, and His-351, whose mutation to alanine significantly reduced or completely abolished enzymatic activity. Our study characterizes the substrate specificity and kinetic parameters of TDP2. In addition, a two-metal catalytic mechanism is proposed.
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Affiliation(s)
- Rui Gao
- Laboratory of Molecular Pharmacology, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, MD 20892, USA
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