51
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Waheed SO, Ramanan R, Chaturvedi SS, Ainsley J, Evison M, Ames JM, Schofield CJ, Christov CZ, Karabencheva-Christova TG. Conformational flexibility influences structure-function relationships in nucleic acid N-methyl demethylases. Org Biomol Chem 2019; 17:2223-2231. [PMID: 30720838 DOI: 10.1039/c9ob00162j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
N-Methylation of DNA/RNA bases can be regulatory or damaging and is linked to diseases including cancer and genetic disorders. Bacterial AlkB and human FTO are DNA/RNA demethylases belonging to the Fe(ii) and 2-oxoglutarate oxygenase superfamily. Modelling studies reveal conformational dynamics influence structure-function relationships of AlkB and FTO, e.g. why 1-methyladenine is a better substrate for AlkB than 6-methyladenine. Simulations show that the flexibility of the double stranded DNA substrate in AlkB influences correlated motions, including between the core jelly-roll fold and an active site loop involved in substrate binding. The FTO N- and C-terminal domains move in respect to one another in a manner likely important for substrate binding. Substitutions, including clinically observed ones, influencing catalysis contribute to the network of correlated motions in AlkB and FTO. Overall, the calculations highlight the importance of the overall protein environment and its flexibility to the geometry of the reactant complexes.
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Affiliation(s)
- Sodiq O Waheed
- Department of Chemistry, Michigan Technological University, Houghton, Michigan 49931, USA.
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52
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Structural insights into FTO's catalytic mechanism for the demethylation of multiple RNA substrates. Proc Natl Acad Sci U S A 2019; 116:2919-2924. [PMID: 30718435 PMCID: PMC6386707 DOI: 10.1073/pnas.1820574116] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The RNA modification N6-methyladenosine (m6A) was the first physiological substrate of FTO to be discovered. Recently, cap N6,2′-O-dimethyladenosine (m6Am), internal m6Am, and N1-methyladenosine were also found to be physiological substrates of FTO. However, the catalytic mechanism through which FTO demethylates its multiple RNA substrates remains largely mysterious. Here we present the first structure of FTO bound to N6-methyldeoxyadenosine–modified ssDNA. We show that N6-methyladenine is the most favorable nucleobase substrate of FTO and that the sequence and the tertiary structure of RNA can affect the catalytic activity of FTO. Our findings provide a structural basis for understanding FTO’s catalytic mechanism for the demethylation of multiple RNA substrates and shed light on the mechanism through which FTO is involved in diseases or biological processes. FTO demethylates internal N6-methyladenosine (m6A) and N6,2′-O-dimethyladenosine (m6Am; at the cap +1 position) in mRNA, m6A and m6Am in snRNA, and N1-methyladenosine (m1A) in tRNA in vivo, and in vitro evidence supports that it can also demethylate N6-methyldeoxyadenosine (6mA), 3-methylthymine (3mT), and 3-methyluracil (m3U). However, it remains unclear how FTO variously recognizes and catalyzes these diverse substrates. Here we demonstrate—in vitro and in vivo—that FTO has extensive demethylation enzymatic activity on both internal m6A and cap m6Am. Considering that 6mA, m6A, and m6Am all share the same nucleobase, we present a crystal structure of human FTO bound to 6mA-modified ssDNA, revealing the molecular basis of the catalytic demethylation of FTO toward multiple RNA substrates. We discovered that (i) N6-methyladenine is the most favorable nucleobase substrate of FTO, (ii) FTO displays the same demethylation activity toward internal m6A and m6Am in the same RNA sequence, suggesting that the substrate specificity of FTO primarily results from the interaction of residues in the catalytic pocket with the nucleobase (rather than the ribose ring), and (iii) the sequence and the tertiary structure of RNA can affect the catalytic activity of FTO. Our findings provide a structural basis for understanding the catalytic mechanism through which FTO demethylates its multiple substrates and pave the way forward for the structure-guided design of selective chemicals for functional studies and potential therapeutic applications.
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53
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Lee SJ, Sung RJ, Verdine GL. Mechanism of DNA Lesion Homing and Recognition by the Uvr Nucleotide Excision Repair System. RESEARCH (WASHINGTON, D.C.) 2019; 2019:5641746. [PMID: 31549070 PMCID: PMC6750098 DOI: 10.34133/2019/5641746] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 06/26/2019] [Indexed: 11/06/2022]
Abstract
Nucleotide excision repair (NER) is an essential DNA repair system distinguished from other such systems by its extraordinary versatility. NER removes a wide variety of structurally dissimilar lesions having only their bulkiness in common. NER can also repair several less bulky nucleobase lesions, such as 8-oxoguanine. Thus, how a single DNA repair system distinguishes such a diverse array of structurally divergent lesions from undamaged DNA has been one of the great unsolved mysteries in the field of genome maintenance. Here we employ a synthetic crystallography approach to obtain crystal structures of the pivotal NER enzyme UvrB in complex with duplex DNA, trapped at the stage of lesion-recognition. These structures coupled with biochemical studies suggest that UvrB integrates the ATPase-dependent helicase/translocase and lesion-recognition activities. Our work also conclusively establishes the identity of the lesion-containing strand and provides a compelling insight to how UvrB recognizes a diverse array of DNA lesions.
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Affiliation(s)
- Seung-Joo Lee
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
| | - Rou-Jia Sung
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Gregory L. Verdine
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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54
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Yang C, Kim E, Lim M, Pak Y. Computational Probing of Watson-Crick/Hoogsteen Breathing in a DNA Duplex Containing N1-Methylated Adenine. J Chem Theory Comput 2018; 15:751-761. [PMID: 30501194 DOI: 10.1021/acs.jctc.8b00936] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
DNA breathing is a local conformational fluctuation spontaneously occurring in double-stranded DNAs. In particular, the possibility of individual base pairs (bps) in duplex DNA to flip between alternate bp modes, i.e., Watson-Crick (WC)-like and Hoogsteen (HG)-like, at relevant time scales has impacted DNA research fields for many years. In this study, to computationally probe effects of chemical modification on the DNA breathing, we present a free energy landscape of spontaneous thermal transitions between WC and HG bps in a free DNA duplex containing N1-methylated adenine (m1A). For the current free energy computation, a variant of well-tempered metadynamics simulation was extensively performed for a total of 40 μs to produce free energy surfaces. The free energy profile indicated that, upon the chemical modification of adenine, the HG bp (m1A·T) was located in the most favorable conformation (96.7%); however, the canonical WC bp (m1A·T) was distorted into two WC-like bps of WC* (2.8%) and WC** (0.5%). The conformational exchange between these two minor WC-like bps occurs with the first hundred nanoseconds. The transition between WC-like and HG bp features multiple transition pathways displaying various extents of base flipping in combination with glycosidic rotation. Analysis of the simulated ensemble showed that the m1A-induced changes of the backbone and sugar pucker were in a reasonable agreement with previous results inferred from NMR experiments. Also, this study revealed that the formation of the stable HG bp upon the mutation alters the characteristics of dynamic fluctuations of the neighboring WC residues of m1A. We expect this simulation approach to be a robust computational scheme to complement and guide future high-resolution experiments on many outstanding issues of duplex DNA breathing.
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Affiliation(s)
- Changwon Yang
- Department of Chemistry and Institute of Functional Materials , Pusan National University , Busan 46241 , South Korea
| | - Eunae Kim
- College of Pharmacy , Chosun University , Gwangju 61452 , South Korea
| | - Manho Lim
- Department of Chemistry and Institute of Functional Materials , Pusan National University , Busan 46241 , South Korea
| | - Youngshang Pak
- Department of Chemistry and Institute of Functional Materials , Pusan National University , Busan 46241 , South Korea
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55
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Rajecka V, Skalicky T, Vanacova S. The role of RNA adenosine demethylases in the control of gene expression. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:343-355. [PMID: 30550773 DOI: 10.1016/j.bbagrm.2018.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 01/21/2023]
Abstract
RNA modifications are being recognized as an essential factor in gene expression regulation. They play essential roles in germ line development, differentiation and disease. In eukaryotic mRNAs, N6-adenosine methylation (m6A) is the most prevalent internal chemical modification identified to date. The m6A pathway involves factors called writers, readers and erasers. m6A thus offers an interesting concept of dynamic reversible modification with implications in fine-tuning the cellular metabolism. In mammals, FTO and ALKBH5 have been initially identified as m6A erasers. Recently, FTO m6A specificity has been debated as new reports identify FTO targeting N6,2'-O-dimethyladenosine (m6Am). The two adenosine demethylases have diverse roles in the metabolism of mRNAs and their activity is involved in key processes, such as embryogenesis, disease or infection. In this article, we review the current knowledge of their function and mechanisms and discuss the existing contradictions in the field. This article is part of a Special Issue entitled: mRNA modifications in gene expression control edited by Dr. Soller Matthias and Dr. Fray Rupert.
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Affiliation(s)
- Veronika Rajecka
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 625 00, Czech Republic
| | - Tomas Skalicky
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 625 00, Czech Republic
| | - Stepanka Vanacova
- Central European Institute of Technology (CEITEC), Masaryk University, Brno 625 00, Czech Republic.
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56
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Thapar R, Bacolla A, Oyeniran C, Brickner JR, Chinnam NB, Mosammaparast N, Tainer JA. RNA Modifications: Reversal Mechanisms and Cancer. Biochemistry 2018; 58:312-329. [PMID: 30346748 DOI: 10.1021/acs.biochem.8b00949] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An emerging molecular understanding of RNA alkylation and its removal is transforming our knowledge of RNA biology and its interplay with cancer chemotherapy responses. DNA modifications are known to perform critical functions depending on the genome template, including gene expression, DNA replication timing, and DNA damage protection, yet current results suggest that the chemical diversity of DNA modifications pales in comparison to those on RNA. More than 150 RNA modifications have been identified to date, and their complete functional implications are still being unveiled. These include intrinsic roles such as proper processing and RNA maturation; emerging evidence has furthermore uncovered RNA modification "readers", seemingly analogous to those identified for histone modifications. These modification recognition factors may regulate mRNA stability, localization, and interaction with translation machinery, affecting gene expression. Not surprisingly, tumors differentially modulate factors involved in expressing these marks, contributing to both tumorigenesis and responses to alkylating chemotherapy. Here we describe the current understanding of RNA modifications and their removal, with a focus primarily on methylation and alkylation as functionally relevant changes to the transcriptome. Intriguingly, some of the same RNA modifications elicited by physiological processes are also produced by alkylating agents, thus blurring the lines between what is a physiological mark and a damage-induced modification. Furthermore, we find that a high level of gene expression of enzymes with RNA dealkylation activity is a sensitive readout for poor survival in four different cancer types, underscoring the likely importance of examining RNA dealkylation mechanisms to cancer biology and for cancer treatment and prognosis.
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Affiliation(s)
- Roopa Thapar
- Department of Molecular and Cellular Oncology , University of Texas M. D. Anderson Cancer Center , Houston , Texas 77030 , United States
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology , University of Texas M. D. Anderson Cancer Center , Houston , Texas 77030 , United States
| | - Clement Oyeniran
- Department of Pathology and Immunology, Siteman Cancer Center , Washington University in St. Louis School of Medicine , St. Louis , Missouri 63110 , United States
| | - Joshua R Brickner
- Department of Pathology and Immunology, Siteman Cancer Center , Washington University in St. Louis School of Medicine , St. Louis , Missouri 63110 , United States
| | - Naga Babu Chinnam
- Department of Molecular and Cellular Oncology , University of Texas M. D. Anderson Cancer Center , Houston , Texas 77030 , United States
| | - Nima Mosammaparast
- Department of Pathology and Immunology, Siteman Cancer Center , Washington University in St. Louis School of Medicine , St. Louis , Missouri 63110 , United States
| | - John A Tainer
- Department of Molecular and Cellular Oncology , University of Texas M. D. Anderson Cancer Center , Houston , Texas 77030 , United States
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57
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Cheong A, Low JJA, Lim A, Yen PM, Woon ECY. A fluorescent methylation-switchable probe for highly sensitive analysis of FTO N 6-methyladenosine demethylase activity in cells. Chem Sci 2018; 9:7174-7185. [PMID: 30288236 PMCID: PMC6149071 DOI: 10.1039/c8sc02163e] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/01/2018] [Indexed: 01/25/2023] Open
Abstract
N 6-Methyladenosine (m6A) is one of the most abundant epigenetic modifications on mRNA. It is dynamically regulated by the m6A demethylases FTO and ALKBH5, which are currently attracting intense medical interest because of their strong association with several human diseases. Despite their clinical significance, the molecular mechanisms of m6A demethylases remain unclear, hence there is tremendous interest in developing analytical tools to facilitate their functional studies, with a longer term view of validating their therapeutic potentials. To date, no method exists which permits the analysis of m6A-demethylase activity in cells. To overcome this challenge, herein, we describe the first example of a fluorescent m6A-switchable oligonucleotide probe, which enables the direct detection of FTO demethylase activity both in vitro and in living cells. The m6A probe provides a simple, yet powerful visual tool for highly sensitive detection of demethylase activity. Through the use of m6A-probe, we were able to achieve real-time imaging and single-cell flow cytometry analyses of FTO activity in HepG2 cells. We also successfully applied the probe to monitor dynamic changes in FTO activity and m6A methylation levels during 3T3-L1 pre-adipocyte differentiation. The strategy outlined here is highly versatile and may, in principle, be adapted to the study of a range of RNA demethylases and, more widely, other RNA modifying enzymes. To the best of our knowledge, the present study represents not only the first assay for monitoring FTO activity in living cells, but also a new strategy for sensing m6A methylation dynamics.
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Affiliation(s)
- Adeline Cheong
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Joanne J A Low
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Andrea Lim
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
- Program of Cardiovascular and Metabolic Disorders , Duke-NUS Medical School , 8 College Road , 169857 , Singapore
| | - Paul M Yen
- Program of Cardiovascular and Metabolic Disorders , Duke-NUS Medical School , 8 College Road , 169857 , Singapore
| | - Esther C Y Woon
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
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58
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Wei J, Liu F, Lu Z, Fei Q, Ai Y, He PC, Shi H, Cui X, Su R, Klungland A, Jia G, Chen J, He C. Differential m 6A, m 6A m, and m 1A Demethylation Mediated by FTO in the Cell Nucleus and Cytoplasm. Mol Cell 2018; 71:973-985.e5. [PMID: 30197295 PMCID: PMC6151148 DOI: 10.1016/j.molcel.2018.08.011] [Citation(s) in RCA: 468] [Impact Index Per Article: 78.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 06/03/2018] [Accepted: 08/02/2018] [Indexed: 10/28/2022]
Abstract
FTO, the first RNA demethylase discovered, mediates the demethylation of internal N6-methyladenosine (m6A) and N6, 2-O-dimethyladenosine (m6Am) at the +1 position from the 5' cap in mRNA. Here we demonstrate that the cellular distribution of FTO is distinct among different cell lines, affecting the access of FTO to different RNA substrates. We find that FTO binds multiple RNA species, including mRNA, snRNA, and tRNA, and can demethylate internal m6A and cap m6Am in mRNA, internal m6A in U6 RNA, internal and cap m6Am in snRNAs, and N1-methyladenosine (m1A) in tRNA. FTO-mediated demethylation has a greater effect on the transcript levels of mRNAs possessing internal m6A than the ones with cap m6Am in the tested cells. We also show that FTO can directly repress translation by catalyzing m1A tRNA demethylation. Collectively, FTO-mediated RNA demethylation occurs to m6A and m6Am in mRNA and snRNA as well as m1A in tRNA.
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Affiliation(s)
- Jiangbo Wei
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - Fange Liu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - Zhike Lu
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Institute of Natural Sciences, Westlake Institute for Advanced Study, Westlake University, 18 Shilongshan Road, Hangzhou 310064, China
| | - Qili Fei
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - Yuxi Ai
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - P Cody He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - Hailing Shi
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - Xiaolong Cui
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA
| | - Rui Su
- Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA
| | - Arne Klungland
- Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, Norway Institute of Basic Medical Sciences, University of Oslo, PO Box 1018 Blindern, 0315 Oslo, Norway
| | - 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
| | - Jianjun Chen
- Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA 91016, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, and Institute for Biophysical Dynamics, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, 929 East 57 Street, Chicago, IL 60637, USA.
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59
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Das M, Yang T, Dong J, Prasetya F, Xie Y, Wong KHQ, Cheong A, Woon ECY. Multiprotein Dynamic Combinatorial Chemistry: A Strategy for the Simultaneous Discovery of Subfamily-Selective Inhibitors for Nucleic Acid Demethylases FTO and ALKBH3. Chem Asian J 2018; 13:2854-2867. [PMID: 29917331 DOI: 10.1002/asia.201800729] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 06/12/2018] [Indexed: 12/18/2022]
Abstract
Dynamic combinatorial chemistry (DCC) is a powerful supramolecular approach for discovering ligands for biomolecules. To date, most, if not all, biologically templated DCC systems employ only a single biomolecule to direct the self-assembly process. To expand the scope of DCC, herein, a novel multiprotein DCC strategy has been developed that combines the discriminatory power of a zwitterionic "thermal tag" with the sensitivity of differential scanning fluorimetry. This strategy is highly sensitive and could differentiate the binding of ligands to structurally similar subfamily members. Through this strategy, it was possible to simultaneously identify subfamily-selective probes against two clinically important epigenetic enzymes: FTO (7; IC50 =2.6 μm) and ALKBH3 (8; IC50 =3.7 μm). To date, this is the first report of a subfamily-selective ALKBH3 inhibitor. The developed strategy could, in principle, be adapted to a broad range of proteins; thus it is of broad scientific interest.
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MESH Headings
- AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase/antagonists & inhibitors
- AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase/chemistry
- AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase/genetics
- AlkB Homolog 5, RNA Demethylase/antagonists & inhibitors
- AlkB Homolog 5, RNA Demethylase/chemistry
- AlkB Homolog 5, RNA Demethylase/genetics
- Alpha-Ketoglutarate-Dependent Dioxygenase FTO/antagonists & inhibitors
- Alpha-Ketoglutarate-Dependent Dioxygenase FTO/chemistry
- Alpha-Ketoglutarate-Dependent Dioxygenase FTO/genetics
- Catalysis
- Combinatorial Chemistry Techniques/methods
- Enzyme Inhibitors/chemistry
- Fluorometry/methods
- Humans
- Hydrazones/chemistry
- Kinetics
- Ligands
- Molecular Structure
- Oxidoreductases, O-Demethylating/antagonists & inhibitors
- Oxidoreductases, O-Demethylating/chemistry
- Oxidoreductases, O-Demethylating/genetics
- Peptides/chemistry
- Peptides/genetics
- Protein Denaturation
- Protein Engineering
- Protein Structure, Secondary
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Transition Temperature
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Affiliation(s)
- Mohua Das
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Tianming Yang
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Jinghua Dong
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Fransisca Prasetya
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Yiming Xie
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Kendra H Q Wong
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Adeline Cheong
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
| | - Esther C Y Woon
- Department of Pharmacy, National University of Singapore, 18 Science Drive 4, Singapore, 117543, Singapore
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60
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Wilson DL, Beharry AA, Srivastava A, O'Connor TR, Kool ET. Fluorescence Probes for ALKBH2 Allow the Measurement of DNA Alkylation Repair and Drug Resistance Responses. Angew Chem Int Ed Engl 2018; 57:12896-12900. [PMID: 30098084 DOI: 10.1002/anie.201807593] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Indexed: 01/18/2023]
Abstract
The DNA repair enzyme ALKBH2 is implicated in both tumorigenesis as well as resistance to chemotherapy in certain cancers. It is currently under study as a potential diagnostic marker and has been proposed as a therapeutic target. To date, however, there exist no direct methods for measuring the repair activity of ALKBH2 in vitro or in biological samples. Herein, we report a highly specific, fluorogenic probe design based on an oligonucleotide scaffold that reports directly on ALKBH2 activity both in vitro and in cell lysates. Importantly, the probe enables the monitoring of cellular regulation of ALKBH2 activity in response to treatment with the chemotherapy drug temozolomide through a simple fluorescence assay, which has only previously been observed through indirect means such as qPCR and western blots. Furthermore, the probe provides a viable high-throughput assay for drug discovery.
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Affiliation(s)
- David L Wilson
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Andrew A Beharry
- Department of Chemical and Physical Sciences, University of Toronto, Mississauga, ON, L5L 1C6, Canada
| | - Avinash Srivastava
- Department of Cancer Biology, Beckman Research Institute, Duarte, CA, 91010, USA
| | - Timothy R O'Connor
- Department of Cancer Biology, Beckman Research Institute, Duarte, CA, 91010, USA
| | - Eric T Kool
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
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61
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Wilson DL, Beharry AA, Srivastava A, O'Connor TR, Kool ET. Fluorescence Probes for ALKBH2 Allow the Measurement of DNA Alkylation Repair and Drug Resistance Responses. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807593] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- David L. Wilson
- Department of Chemistry; Stanford University; Stanford CA 94305 USA
| | - Andrew A. Beharry
- Department of Chemical and Physical Sciences; University of Toronto; Mississauga ON L5L 1C6 Canada
| | - Avinash Srivastava
- Department of Cancer Biology; Beckman Research Institute; Duarte CA 91010 USA
| | - Timothy R. O'Connor
- Department of Cancer Biology; Beckman Research Institute; Duarte CA 91010 USA
| | - Eric T. Kool
- Department of Chemistry; Stanford University; Stanford CA 94305 USA
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62
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Gao SS, Naowarojna N, Cheng R, Liu X, Liu P. Recent examples of α-ketoglutarate-dependent mononuclear non-haem iron enzymes in natural product biosyntheses. Nat Prod Rep 2018; 35:792-837. [PMID: 29932179 PMCID: PMC6093783 DOI: 10.1039/c7np00067g] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Covering: up to 2018 α-Ketoglutarate (αKG, also known as 2-oxoglutarate)-dependent mononuclear non-haem iron (αKG-NHFe) enzymes catalyze a wide range of biochemical reactions, including hydroxylation, ring fragmentation, C-C bond cleavage, epimerization, desaturation, endoperoxidation and heterocycle formation. These enzymes utilize iron(ii) as the metallo-cofactor and αKG as the co-substrate. Herein, we summarize several novel αKG-NHFe enzymes involved in natural product biosyntheses discovered in recent years, including halogenation reactions, amino acid modifications and tailoring reactions in the biosynthesis of terpenes, lipids, fatty acids and phosphonates. We also conducted a survey of the currently available structures of αKG-NHFe enzymes, in which αKG binds to the metallo-centre bidentately through either a proximal- or distal-type binding mode. Future structure-function and structure-reactivity relationship investigations will provide crucial information regarding how activities in this large class of enzymes have been fine-tuned in nature.
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Affiliation(s)
- Shu-Shan Gao
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | | | - Ronghai Cheng
- Department of Chemistry, Boston University, Boston, MA 02215, USA.
| | - Xueting Liu
- Department of Chemistry, Boston University, Boston, MA 02215, USA. and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, MA 02215, USA.
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63
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Zhou C, Wang C, Liu H, Zhou Q, Liu Q, Guo Y, Peng T, Song J, Zhang J, Chen L, Zhao Y, Zeng Z, Zhou DX. Identification and analysis of adenine N 6-methylation sites in the rice genome. NATURE PLANTS 2018; 4:554-563. [PMID: 30061746 DOI: 10.1038/s41477-018-0214-x] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 07/04/2018] [Indexed: 05/22/2023]
Abstract
DNA N6-methyladenine (6mA) is a non-canonical DNA modification that is present at low levels in different eukaryotes1-8, but its prevalence and genomic function in higher plants are unclear. Using mass spectrometry, immunoprecipitation and validation with analysis of single-molecule real-time sequencing, we observed that about 0.2% of all adenines are 6mA methylated in the rice genome. 6mA occurs most frequently at GAGG motifs and is mapped to about 20% of genes and 14% of transposable elements. In promoters, 6mA marks silent genes, but in bodies correlates with gene activity. 6mA overlaps with 5-methylcytosine (5mC) at CG sites in gene bodies and is complementary to 5mC at CHH sites in transposable elements. We show that OsALKBH1 may be potentially involved in 6mA demethylation in rice. The results suggest that 6mA is complementary to 5mC as an epigenomic mark in rice and reinforce a distinct role for 6mA as a gene expression-associated epigenomic mark in eukaryotes.
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Affiliation(s)
- Chao Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Changshi Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Hongbo Liu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Qiangwei Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Qian Liu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Yan Guo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Ting Peng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Jiaming Song
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Jianwei Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Lingling Chen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Zhixiong Zeng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China.
- Institute of Plant Science of Paris-Saclay (IPS2), CNRS, INRA, Université Paris-sud 11, Université Paris-Saclay, Orsay, France.
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64
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Boriack-Sjodin PA, Ribich S, Copeland RA. RNA-modifying proteins as anticancer drug targets. Nat Rev Drug Discov 2018; 17:435-453. [PMID: 29773918 DOI: 10.1038/nrd.2018.71] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
All major biological macromolecules (DNA, RNA, proteins and lipids) undergo enzyme-catalysed covalent modifications that impact their structure, function and stability. A variety of covalent modifications of RNA have been identified and demonstrated to affect RNA stability and translation to proteins; these mechanisms of translational control have been termed epitranscriptomics. Emerging data suggest that some epitranscriptomic mechanisms are altered in human cancers as well as other human diseases. In this Review, we examine the current understanding of RNA modifications with a focus on mRNA methylation, highlight their possible roles in specific cancer indications and discuss the emerging potential of RNA-modifying proteins as therapeutic targets.
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65
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Huang J, Yin P. Structural Insights into N 6-methyladenosine (m 6A) Modification in the Transcriptome. GENOMICS PROTEOMICS & BIOINFORMATICS 2018; 16:85-98. [PMID: 29709557 PMCID: PMC6112310 DOI: 10.1016/j.gpb.2018.03.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 03/28/2018] [Accepted: 03/29/2018] [Indexed: 01/04/2023]
Abstract
More than 100 types of chemical modifications in RNA have been well documented. Recently, several modifications, such as N6-methyladenosine (m6A), have been detected in mRNA, opening the window into the realm of epitranscriptomics. The m6A modification is the most abundant modification in mRNA and non-coding RNA (ncRNA). At the molecular level, m6A affects almost all aspects of mRNA metabolism, including splicing, translation, and stability, as well as microRNA (miRNA) maturation, playing essential roles in a range of cellular processes. The m6A modification is regulated by three classes of proteins generally referred to as the “writer” (adenosine methyltransferase), “eraser” (m6A demethylating enzyme), and “reader” (m6A-binding protein). The m6A modification is reversibly installed and removed by writers and erasers, respectively. Readers, which are members of the YT521-B homology (YTH) family proteins, selectively bind to RNA and affect its fate in an m6A-dependent manner. In this review, we summarize the structures of the functional proteins that modulate the m6A modification, and provide our insights into the m6A-mediated gene regulation.
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Affiliation(s)
- Jinbo Huang
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China.
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66
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Shi H, Clay MC, Rangadurai A, Sathyamoorthy B, Case DA, Al-Hashimi HM. Atomic structures of excited state A-T Hoogsteen base pairs in duplex DNA by combining NMR relaxation dispersion, mutagenesis, and chemical shift calculations. JOURNAL OF BIOMOLECULAR NMR 2018; 70:229-244. [PMID: 29675775 PMCID: PMC6048961 DOI: 10.1007/s10858-018-0177-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/29/2018] [Indexed: 05/20/2023]
Abstract
NMR relaxation dispersion studies indicate that in canonical duplex DNA, Watson-Crick base pairs (bps) exist in dynamic equilibrium with short-lived low abundance excited state Hoogsteen bps. N1-methylated adenine (m1A) and guanine (m1G) are naturally occurring forms of damage that stabilize Hoogsteen bps in duplex DNA. NMR dynamic ensembles of DNA duplexes with m1A-T Hoogsteen bps reveal significant changes in sugar pucker and backbone angles in and around the Hoogsteen bp, as well as kinking of the duplex towards the major groove. Whether these structural changes also occur upon forming excited state Hoogsteen bps in unmodified duplexes remains to be established because prior relaxation dispersion probes provided limited information regarding the sugar-backbone conformation. Here, we demonstrate measurements of C3' and C4' spin relaxation in the rotating frame (R1ρ) in uniformly 13C/15N labeled DNA as sensitive probes of the sugar-backbone conformation in DNA excited states. The chemical shifts, combined with structure-based predictions using an automated fragmentation quantum mechanics/molecular mechanics method, show that the dynamic ensemble of DNA duplexes containing m1A-T Hoogsteen bps accurately model the excited state Hoogsteen conformation in two different sequence contexts. Formation of excited state A-T Hoogsteen bps is accompanied by changes in sugar-backbone conformation that allow the flipped syn adenine to form hydrogen-bonds with its partner thymine and this in turn results in overall kinking of the DNA toward the major groove. Results support the assignment of Hoogsteen bps as the excited state observed in canonical duplex DNA, provide an atomic view of DNA dynamics linked to formation of Hoogsteen bps, and lay the groundwork for a potentially general strategy for solving structures of nucleic acid excited states.
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Affiliation(s)
- Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Mary C. Clay
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Bharathwaj Sathyamoorthy
- Department of Chemistry, Duke University, Durham, NC 27710, USA
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - David A. Case
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854, USA
- To whom correspondence should be addressed. Telephone: (919) 660-1113, or
| | - Hashim M. Al-Hashimi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- To whom correspondence should be addressed. Telephone: (919) 660-1113, or
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67
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Wilkins SE, Islam MS, Gannon JM, Markolovic S, Hopkinson RJ, Ge W, Schofield CJ, Chowdhury R. JMJD5 is a human arginyl C-3 hydroxylase. Nat Commun 2018; 9:1180. [PMID: 29563586 PMCID: PMC5862942 DOI: 10.1038/s41467-018-03410-w] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 02/12/2018] [Indexed: 12/21/2022] Open
Abstract
Oxygenase-catalysed post-translational modifications of basic protein residues, including lysyl hydroxylations and Nε-methyl lysyl demethylations, have important cellular roles. Jumonji-C (JmjC) domain-containing protein 5 (JMJD5), which genetic studies reveal is essential in animal development, is reported as a histone Nε-methyl lysine demethylase (KDM). Here we report how extensive screening with peptides based on JMJD5 interacting proteins led to the finding that JMJD5 catalyses stereoselective C-3 hydroxylation of arginine residues in sequences from human regulator of chromosome condensation domain-containing protein 1 (RCCD1) and ribosomal protein S6 (RPS6). High-resolution crystallographic analyses reveal overall fold, active site and substrate binding/product release features supporting the assignment of JMJD5 as an arginine hydroxylase rather than a KDM. The results will be useful in the development of selective oxygenase inhibitors for the treatment of cancer and genetic diseases.
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Affiliation(s)
- Sarah E Wilkins
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Md Saiful Islam
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Joan M Gannon
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Suzana Markolovic
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Richard J Hopkinson
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
- Leicester Institute of Structural and Chemical Biology and Department of Chemistry, University of Leicester, Lancaster Road, Leicester, LE1 7RH, UK
| | - Wei Ge
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | | | - Rasheduzzaman Chowdhury
- The Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
- Stanford University School of Medicine, Department of Molecular and Cellular Physiology, Clark Center, Stanford, CA, 94305-5345, USA.
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68
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Tahara YK, Auld D, Ji D, Beharry AA, Kietrys AM, Wilson DL, Jimenez M, King D, Nguyen Z, Kool ET. Potent and Selective Inhibitors of 8-Oxoguanine DNA Glycosylase. J Am Chem Soc 2018; 140:2105-2114. [PMID: 29376367 PMCID: PMC5823510 DOI: 10.1021/jacs.7b09316] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The activity of DNA repair enzyme 8-oxoguanine DNA glycosylase (OGG1), which excises oxidized base 8-oxoguanine (8-OG) from DNA, is closely linked to mutagenesis, genotoxicity, cancer, and inflammation. To test the roles of OGG1-mediated repair in these pathways, we have undertaken the development of noncovalent small-molecule inhibitors of the enzyme. Screening of a PubChem-annotated library using a recently developed fluorogenic 8-OG excision assay resulted in multiple validated hit structures, including selected lead hit tetrahydroquinoline 1 (IC50 = 1.7 μM). Optimization of the tetrahydroquinoline scaffold over five regions of the structure ultimately yielded amidobiphenyl compound 41 (SU0268; IC50 = 0.059 μM). SU0268 was confirmed by surface plasmon resonance studies to bind the enzyme both in the absence and in the presence of DNA. The compound SU0268 was shown to be selective for inhibiting OGG1 over multiple repair enzymes, including other base excision repair enzymes, and displayed no toxicity in two human cell lines at 10 μM. Finally, experiments confirm the ability of SU0268 to inhibit OGG1 in HeLa cells, resulting in an increase in accumulation of 8-OG in DNA. The results suggest the compound SU0268 as a potentially useful tool in studies of the role of OGG1 in multiple disease-related pathways.
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Affiliation(s)
- Yu-ki Tahara
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Douglas Auld
- Department of Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Debin Ji
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Andrew A. Beharry
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Anna M. Kietrys
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - David L. Wilson
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Marta Jimenez
- Department of Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Daniel King
- Department of Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Zachary Nguyen
- Department of Chemical Biology and Therapeutics, Novartis Institutes for Biomedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Eric T. Kool
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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69
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Ravichandran M, Jurkowska RZ, Jurkowski TP. Target specificity of mammalian DNA methylation and demethylation machinery. Org Biomol Chem 2018; 16:1419-1435. [DOI: 10.1039/c7ob02574b] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We review here the molecular mechanisms employed by DNMTs and TET enzymes that are responsible for shaping the DNA methylation pattern of a mammalian cell.
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Affiliation(s)
| | | | - T. P. Jurkowski
- Universität Stuttgart
- Abteilung Biochemie
- Institute für Biochemie und Technische Biochemie
- Stuttgart D-70569
- Germany
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70
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Jayanth N, Ogirala N, Yadav A, Puranik M. Structural basis for substrate discrimination by E. colirepair enzyme, AlkB. RSC Adv 2018; 8:1281-1291. [PMID: 35540905 PMCID: PMC9076979 DOI: 10.1039/c7ra11333a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 11/14/2017] [Indexed: 11/21/2022] Open
Abstract
Positive charge on methylated nucleotides is a prime criterion for substrate recognition byE. coliAlkB.
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Affiliation(s)
- Namrata Jayanth
- National Centre for Biological Sciences
- Tata Institute of Fundamental Research
- GKVK Campus
- Bangalore 560065
- India
| | - Nirmala Ogirala
- National Centre for Biological Sciences
- Tata Institute of Fundamental Research
- GKVK Campus
- Bangalore 560065
- India
| | - Anil Yadav
- Indian Institute of Science Education and Research (IISER)
- Pune
- India
| | - Mrinalini Puranik
- National Centre for Biological Sciences
- Tata Institute of Fundamental Research
- GKVK Campus
- Bangalore 560065
- India
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71
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Yin X, Xu Y. Structure and Function of TET Enzymes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 945:275-302. [PMID: 27826843 DOI: 10.1007/978-3-319-43624-1_12] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Mammalian DNA methylation mainly occurs at the carbon-C5 position of cytosine (5mC). TET enzymes were discovered to successively oxidize 5mC to 5-hydromethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC). TET enzymes and oxidized 5mC derivatives play important roles in various biological and pathological processes, including regulation of DNA demethylation, gene transcription, embryonic development, and oncogenesis. In this chapter, we will discuss the discovery of TET-mediated 5mC oxidation and the structure, function, and regulation of TET enzymes.
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Affiliation(s)
- Xiaotong Yin
- Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China
| | - Yanhui Xu
- Fudan University Shanghai Cancer Center, Institute of Biomedical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China.
- Key Laboratory of Molecular Medicine, Ministry of Education, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, 200032, China.
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, 200433, China.
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72
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Sathyamoorthy B, Shi H, Zhou H, Xue Y, Rangadurai A, Merriman DK, Al-Hashimi HM. Insights into Watson-Crick/Hoogsteen breathing dynamics and damage repair from the solution structure and dynamic ensemble of DNA duplexes containing m1A. Nucleic Acids Res 2017; 45:5586-5601. [PMID: 28369571 PMCID: PMC5435913 DOI: 10.1093/nar/gkx186] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/06/2017] [Accepted: 03/17/2017] [Indexed: 12/18/2022] Open
Abstract
In the canonical DNA double helix, Watson-Crick (WC) base pairs (bps) exist in dynamic equilibrium with sparsely populated (∼0.02-0.4%) and short-lived (lifetimes ∼0.2-2.5 ms) Hoogsteen (HG) bps. To gain insights into transient HG bps, we used solution-state nuclear magnetic resonance spectroscopy, including measurements of residual dipolar couplings and molecular dynamics simulations, to examine how a single HG bp trapped using the N1-methylated adenine (m1A) lesion affects the structural and dynamic properties of two duplexes. The solution structure and dynamic ensembles of the duplexes reveals that in both cases, m1A forms a m1A•T HG bp, which is accompanied by local and global structural and dynamic perturbations in the double helix. These include a bias toward the BI backbone conformation; sugar repuckering, major-groove directed kinking (∼9°); and local melting of neighboring WC bps. These results provide atomic insights into WC/HG breathing dynamics in unmodified DNA duplexes as well as identify structural and dynamic signatures that could play roles in m1A recognition and repair.
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Affiliation(s)
- Bharathwaj Sathyamoorthy
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Honglue Shi
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Huiqing Zhou
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | - Yi Xue
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27710, USA
| | - Atul Rangadurai
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
| | | | - Hashim M. Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Chemistry, Duke University, Durham, NC 27710, USA
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73
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1,N 6-α-hydroxypropanoadenine, the acrolein adduct to adenine, is a substrate for AlkB dioxygenase. Biochem J 2017; 474:1837-1852. [PMID: 28408432 DOI: 10.1042/bcj20161008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 04/07/2017] [Accepted: 04/13/2017] [Indexed: 11/17/2022]
Abstract
1,N6-α-hydroxypropanoadenine (HPA) is an exocyclic DNA adduct of acrolein - an environmental pollutant and endocellular oxidative stress product. Escherichia coli AlkB dioxygenase belongs to the superfamily of α-ketoglutarate (αKG)- and iron-dependent dioxygenases which remove alkyl lesions from bases via an oxidative mechanism, thereby restoring native DNA structure. Here, we provide in vivo and in vitro evidence that HPA is mutagenic and is effectively repaired by AlkB dioxygenase. HPA generated in plasmid DNA caused A → C and A → T transversions and, less frequently, A → G transitions. The lesion was efficiently repaired by purified AlkB protein; the optimal pH, Fe(II), and αKG concentrations for this reaction were determined. In vitro kinetic data show that the protonated form of HPA is preferentially repaired by AlkB, albeit the reaction is stereoselective. Moreover, the number of reaction cycles carried out by an AlkB molecule remains limited. Molecular modeling of the T(HPA)T/AlkB complex demonstrated that the R stereoisomer in the equatorial conformation of the HPA hydroxyl group is strongly preferred, while the S stereoisomer seems to be susceptible to AlkB-directed oxidative hydroxylation only when HPA adopts the syn conformation around the glycosidic bond. In addition to the biochemical activity assays, substrate binding to the protein was monitored by differential scanning fluorimetry allowing identification of the active protein form, with cofactor and cosubstrate bound, and monitoring of substrate binding. In contrast FTO, a human AlkB homolog, failed to bind an ssDNA trimer carrying HPA.
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74
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Dai Q, Zheng G, Schwartz MH, Clark WC, Pan T. Selective Enzymatic Demethylation of N
2
, N
2
-Dimethylguanosine in RNA and Its Application in High-Throughput tRNA Sequencing. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700537] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Qing Dai
- Department of Chemistry; The University of Chicago; Chicago IL 60637 USA
| | - Guanqun Zheng
- Department of Biochemistry & Molecular Biology; The University of Chicago; Chicago IL 60637 USA
| | - Michael H. Schwartz
- Department of Biochemistry & Molecular Biology; The University of Chicago; Chicago IL 60637 USA
| | - Wesley C. Clark
- Department of Biochemistry & Molecular Biology; The University of Chicago; Chicago IL 60637 USA
| | - Tao Pan
- Department of Biochemistry & Molecular Biology; The University of Chicago; Chicago IL 60637 USA
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75
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Vitamin C in Stem Cell Biology: Impact on Extracellular Matrix Homeostasis and Epigenetics. Stem Cells Int 2017; 2017:8936156. [PMID: 28512473 PMCID: PMC5415867 DOI: 10.1155/2017/8936156] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/05/2017] [Indexed: 12/30/2022] Open
Abstract
Transcription factors and signaling molecules are well-known regulators of stem cell identity and behavior; however, increasing evidence indicates that environmental cues contribute to this complex network of stimuli, acting as crucial determinants of stem cell fate. l-Ascorbic acid (vitamin C (VitC)) has gained growing interest for its multiple functions and mechanisms of action, contributing to the homeostasis of normal tissues and organs as well as to tissue regeneration. Here, we review the main functions of VitC and its effects on stem cells, focusing on its activity as cofactor of Fe+2/αKG dioxygenases, which regulate the epigenetic signatures, the redox status, and the extracellular matrix (ECM) composition, depending on the enzymes' subcellular localization. Acting as cofactor of collagen prolyl hydroxylases in the endoplasmic reticulum, VitC regulates ECM/collagen homeostasis and plays a key role in the differentiation of mesenchymal stem cells towards osteoblasts, chondrocytes, and tendons. In the nucleus, VitC enhances the activity of DNA and histone demethylases, improving somatic cell reprogramming and pushing embryonic stem cell towards the naive pluripotent state. The broad spectrum of actions of VitC highlights its relevance for stem cell biology in both physiology and disease.
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76
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Dai Q, Zheng G, Schwartz MH, Clark WC, Pan T. Selective Enzymatic Demethylation of N 2 ,N 2 -Dimethylguanosine in RNA and Its Application in High-Throughput tRNA Sequencing. Angew Chem Int Ed Engl 2017; 56:5017-5020. [PMID: 28371071 DOI: 10.1002/anie.201700537] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 02/10/2017] [Indexed: 12/17/2022]
Abstract
The abundant Watson-Crick face methylations in biological RNAs such as N1 -methyladenosine (m1 A), N1 -methylguanosine (m1 G), N3 -methylcytosine (m3 C), and N2 ,N2 -dimethylguanosine (m22 G) cause significant obstacles for high-throughput RNA sequencing by impairing cDNA synthesis. One strategy to overcome this obstacle is to remove the methyl group on these modified bases prior to cDNA synthesis using enzymes. The wild-type E. coli AlkB and its D135S mutant can remove most of m1 A, m1 G, m3 C modifications in transfer RNA (tRNA), but they work poorly on m22 G. Here we report the design and evaluation of a series of AlkB mutants against m22 G-containing model RNA substrates that we synthesize using an improved synthetic method. We show that the AlkB D135S/L118V mutant efficiently and selectively converts m22 G modification to N2 -methylguanosine (m2 G). We also show that this new enzyme improves the efficiency of tRNA sequencing.
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Affiliation(s)
- Qing Dai
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA
| | - Guanqun Zheng
- Department of Biochemistry & Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Michael H Schwartz
- Department of Biochemistry & Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Wesley C Clark
- Department of Biochemistry & Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Tao Pan
- Department of Biochemistry & Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
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77
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Chen F, Bian K, Tang Q, Fedeles BI, Singh V, Humulock ZT, Essigmann JM, Li D. Oncometabolites d- and l-2-Hydroxyglutarate Inhibit the AlkB Family DNA Repair Enzymes under Physiological Conditions. Chem Res Toxicol 2017; 30:1102-1110. [PMID: 28269980 DOI: 10.1021/acs.chemrestox.7b00009] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Cancer-associated mutations often lead to perturbed cellular energy metabolism and accumulation of potentially harmful oncometabolites. One example is the chiral molecule 2-hydroxyglutarate (2HG); its two stereoisomers (d- and l-2HG) have been found at abnormally high concentrations in tumors featuring anomalous metabolic pathways. 2HG has been demonstrated to competitively inhibit several α-ketoglutarate (αKG)- and non-heme iron-dependent dioxygenases, including some of the AlkB family DNA repair enzymes, such as ALKBH2 and ALKBH3. However, previous studies have only provided the IC50 values of d-2HG on the enzymes, and the results have not been correlated to physiologically relevant concentrations of 2HG and αKG in cancer cells. In this work, we performed detailed kinetic analyses of DNA repair reactions catalyzed by ALKBH2, ALKBH3, and the bacterial AlkB in the presence of d- and l-2HG in both double- and single-stranded DNA contexts. We determined the kinetic parameters of inhibition, including kcat, KM, and Ki. We also correlated the relative concentrations of 2HG and αKG previously measured in tumor cells with the inhibitory effect of 2HG on the AlkB family enzymes. Both d- and l-2HG significantly inhibited the human DNA repair enzymes ALKBH2 and ALKBH3 at pathologically relevant concentrations (73-88% for d-2HG and 31-58% for l-2HG inhibition). This work provides a new perspective that the elevation of the d- or l-2HG concentration in cancer cells may contribute to an increased mutation rate by inhibiting the DNA repair performed by the AlkB family enzymes and thus exacerbate the genesis and progression of tumors.
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Affiliation(s)
- Fangyi Chen
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Ke Bian
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Qi Tang
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Bogdan I Fedeles
- Department of Biological Engineering, Department of Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Vipender Singh
- Department of Biological Engineering, Department of Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Zachary T Humulock
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - John M Essigmann
- Department of Biological Engineering, Department of Chemistry, and Center for Environmental Health Sciences, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
| | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
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78
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Mechanism of error-free DNA synthesis across N1-methyl-deoxyadenosine by human DNA polymerase-ι. Sci Rep 2017; 7:43904. [PMID: 28272441 PMCID: PMC5341039 DOI: 10.1038/srep43904] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 01/31/2017] [Indexed: 12/17/2022] Open
Abstract
N1-methyl-deoxyadenosine (1-MeA) is formed by methylation of deoxyadenosine at the N1 atom. 1-MeA presents a block to replicative DNA polymerases due to its inability to participate in Watson-Crick (W-C) base pairing. Here we determine how human DNA polymerase-ι (Polι) promotes error-free replication across 1-MeA. Steady state kinetic analyses indicate that Polι is ~100 fold more efficient in incorporating the correct nucleotide T versus the incorrect nucleotide C opposite 1-MeA. To understand the basis of this selectivity, we determined ternary structures of Polι bound to template 1-MeA and incoming dTTP or dCTP. In both structures, template 1-MeA rotates to the syn conformation but pairs differently with dTTP versus dCTP. Thus, whereas dTTP partakes in stable Hoogsteen base pairing with 1-MeA, dCTP fails to gain a "foothold" and is largely disordered. Together, our kinetic and structural studies show how Polι maintains discrimination between correct and incorrect incoming nucleotide opposite 1-MeA in preserving genome integrity.
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79
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Walker AR, Silvestrov P, Müller TA, Podolsky RH, Dyson G, Hausinger RP, Cisneros GA. ALKBH7 Variant Related to Prostate Cancer Exhibits Altered Substrate Binding. PLoS Comput Biol 2017; 13:e1005345. [PMID: 28231280 PMCID: PMC5322872 DOI: 10.1371/journal.pcbi.1005345] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/04/2017] [Indexed: 11/18/2022] Open
Abstract
The search for prostate cancer biomarkers has received increased attention and several DNA repair related enzymes have been linked to this dysfunction. Here we report a targeted search for single nucleotide polymorphisms (SNPs) and functional impact characterization of human ALKBH family dioxygenases related to prostate cancer. Our results uncovered a SNP of ALKBH7, rs7540, which is associated with prostate cancer disease in a statistically significantly manner in two separate cohorts, and maintained in African American men. Comparisons of molecular dynamics (MD) simulations on the wild-type and variant protein structures indicate that the resulting alteration in the enzyme induces a significant structural change that reduces ALKBH7’s ability to bind its cosubstrate. Experimental spectroscopy studies with purified proteins validate our MD predictions and corroborate the conclusion that this cancer-associated mutation affects productive cosubstrate binding in ALKBH7. Improvements in personalized DNA sequencing have led to an increased interest in targeted biomarkers for therapeutic and diagnostic purposes. In this work, we report on a new biomarker for prostate cancer found through a targeted search for single nucleotide polymorphisms (SNPs) of the genes encoding human ALKBH family dioxygenases. Our results uncovered rs7540, which leads to a missense mutation in ALKBH7. Comparative molecular dynamics simulations on the wild type and SNP variant of the protein show that the mutation elicits a structural change that dramatically decreases ALKBH7’s affinity for its cosubstrate. This prediction is confirmed by experimental UV-Vis spectroscopy. Taken together, these results give important insights into a novel prostate-cancer related SNP and its impact on the structure and function of ALKBH7.
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Affiliation(s)
- Alice R. Walker
- Department of Chemistry, Wayne State University, Detroit, MI, United States of America
| | - Pavel Silvestrov
- Department of Chemistry, Wayne State University, Detroit, MI, United States of America
| | - Tina A. Müller
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States of America
| | - Robert H. Podolsky
- Wayne State University Department of Family Medicine and Public Health Sciences, Wayne State University, Detroit, MI, United States of America
| | - Gregory Dyson
- Karmanos Cancer Institute, Wayne State University, Detroit, MI, United States of America
| | - Robert P. Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, United States of America
| | - Gerardo Andrés Cisneros
- Department of Chemistry, Wayne State University, Detroit, MI, United States of America
- * E-mail:
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80
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Yang L, Adhikari J, Gross ML, Li L. Kinetic Isotope Effects and Hydrogen/Deuterium Exchange Reveal Large Conformational Changes During the Catalysis of the Clostridium acetobutylicum Spore Photoproduct Lyase. Photochem Photobiol 2017; 93:331-342. [PMID: 27992649 DOI: 10.1111/php.12697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 11/29/2016] [Indexed: 11/30/2022]
Abstract
Spore photoproduct lyase (SPL) catalyzes the direct reversal of a thymine dimer 5-thyminyl-5,6-dihydrothymine (i.e. the spore photoproduct (SP)) to two thymine residues in germinating endospores. Previous studies suggest that SPL from the bacterium Bacillus subtilis (Bs) harbors an unprecedented radical-transfer pathway starting with cysteine 141 proceeding through tyrosine 99. However, in SPL from the bacterium Clostridium acetobutylicum (Ca), the cysteine (at position 74) and the tyrosine are located on the opposite sides of a substrate-binding pocket that has to collapse to bring the two residues into proximity, enabling the C→Y radical passage as implied in SPL(Bs) . To test this hypothesis, we adopted hydrogen/deuterium exchange mass spectrometry (HDX-MS) to show that C74(Ca) is located at a highly flexible region. The repair of dinucleotide SP TpT by SPL(Ca) is eight-fold to 10-fold slower than that by SPL(Bs) ; the process also generates a large portion of the aborted product TpTSO2- . SPL(Ca) exhibits apparent (D V) kinetic isotope effects (KIEs) of ~6 and abnormally large competitive (D V/K) KIEs (~20), both of which are much larger than the KIEs observed for SPL(Bs) . All these observations indicate that SPL(Ca) possesses a flexible active site and readily undergoes conformational changes during catalysis.
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Affiliation(s)
- Linlin Yang
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN
| | - Jagat Adhikari
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO
| | - Michael L Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, IN.,Department of Biochemistry and Molecular Biology & Department of Dermatology, Indiana University School of Medicine, Indianapolis, IN
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81
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Chowdhury R, Leung IKH, Tian YM, Abboud MI, Ge W, Domene C, Cantrelle FX, Landrieu I, Hardy AP, Pugh CW, Ratcliffe PJ, Claridge TDW, Schofield CJ. Structural basis for oxygen degradation domain selectivity of the HIF prolyl hydroxylases. Nat Commun 2016; 7:12673. [PMID: 27561929 PMCID: PMC5007464 DOI: 10.1038/ncomms12673] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 07/21/2016] [Indexed: 02/06/2023] Open
Abstract
The response to hypoxia in animals involves the expression of multiple genes regulated by the αβ-hypoxia-inducible transcription factors (HIFs). The hypoxia-sensing mechanism involves oxygen limited hydroxylation of prolyl residues in the N- and C-terminal oxygen-dependent degradation domains (NODD and CODD) of HIFα isoforms, as catalysed by prolyl hydroxylases (PHD 1-3). Prolyl hydroxylation promotes binding of HIFα to the von Hippel-Lindau protein (VHL)-elongin B/C complex, thus signalling for proteosomal degradation of HIFα. We reveal that certain PHD2 variants linked to familial erythrocytosis and cancer are highly selective for CODD or NODD. Crystalline and solution state studies coupled to kinetic and cellular analyses reveal how wild-type and variant PHDs achieve ODD selectivity via different dynamic interactions involving loop and C-terminal regions. The results inform on how HIF target gene selectivity is achieved and will be of use in developing selective PHD inhibitors.
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Affiliation(s)
- Rasheduzzaman Chowdhury
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Ivanhoe K. H. Leung
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Ya-Min Tian
- Nuffield Department of Clinical Medicine, University of Oxford, Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Martine I. Abboud
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Wei Ge
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Carmen Domene
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | | | | | - Adam P. Hardy
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Christopher W. Pugh
- Nuffield Department of Clinical Medicine, University of Oxford, Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Peter J. Ratcliffe
- Nuffield Department of Clinical Medicine, University of Oxford, Henry Wellcome Building for Molecular Physiology, Roosevelt Drive, Oxford OX3 7BN, UK
- Ludwig Institute for Cancer Research, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Timothy D. W. Claridge
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
| | - Christopher J. Schofield
- Chemistry Research Laboratory, Department of Chemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK
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82
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Li Q, Huang Y, Liu X, Gan J, Chen H, Yang CG. Rhein Inhibits AlkB Repair Enzymes and Sensitizes Cells to Methylated DNA Damage. J Biol Chem 2016; 291:11083-93. [PMID: 27015802 PMCID: PMC4900258 DOI: 10.1074/jbc.m115.711895] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Indexed: 01/07/2023] Open
Abstract
The AlkB repair enzymes, including Escherichia coli AlkB and two human homologues, ALKBH2 and ALKBH3, are iron(II)- and 2-oxoglutarate-dependent dioxygenases that efficiently repair N(1)-methyladenine and N(3)-methylcytosine methylated DNA damages. The development of small molecule inhibitors of these enzymes has seen less success. Here we have characterized a previously discovered natural product rhein and tested its ability to inhibit AlkB repair enzymes in vitro and to sensitize cells to methyl methane sulfonate that mainly produces N(1)-methyladenine and N(3)-methylcytosine lesions. Our investigation of the mechanism of rhein inhibition reveals that rhein binds to AlkB repair enzymes in vitro and promotes thermal stability in vivo In addition, we have determined a new structural complex of rhein bound to AlkB, which shows that rhein binds to a different part of the active site in AlkB than it binds to in fat mass and obesity-associated protein (FTO). With the support of these observations, we put forth the hypothesis that AlkB repair enzymes would be effective pharmacological targets for cancer treatment.
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Affiliation(s)
- Qi Li
- From the Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yue Huang
- From the Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xichun Liu
- the Coordination Chemistry Institute and State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China, and
| | - Jianhua Gan
- the School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Hao Chen
- the Coordination Chemistry Institute and State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China, and
| | - Cai-Guang Yang
- From the Laboratory of Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China, , To whom correspondence should be addressed. Tel.: 86-21-50806029; Fax: 86-21-50807088; E-mail:
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83
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Simms CL, Zaher HS. Quality control of chemically damaged RNA. Cell Mol Life Sci 2016; 73:3639-53. [PMID: 27155660 DOI: 10.1007/s00018-016-2261-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 04/15/2016] [Accepted: 04/29/2016] [Indexed: 01/10/2023]
Abstract
The "central dogma" of molecular biology describes how information contained in DNA is transformed into RNA and finally into proteins. In order for proteins to maintain their functionality in both the parent cell and subsequent generations, it is essential that the information encoded in DNA and RNA remains unaltered. DNA and RNA are constantly exposed to damaging agents, which can modify nucleic acids and change the information they encode. While much is known about how cells respond to damaged DNA, the importance of protecting RNA has only become appreciated over the past decade. Modification of the nucleobase through oxidation and alkylation has long been known to affect its base-pairing properties during DNA replication. Similarly, recent studies have begun to highlight some of the unwanted consequences of chemical damage on mRNA decoding during translation. Oxidation and alkylation of mRNA appear to have drastic effects on the speed and fidelity of protein synthesis. As some mRNAs can persist for days in certain tissues, it is not surprising that it has recently emerged that mRNA-surveillance and RNA-repair pathways have evolved to clear or correct damaged mRNA.
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Affiliation(s)
- Carrie L Simms
- Department of Biology, Washington University in St. Louis, One Brookings Drive, Campus Box 1137, St. Louis, MO, 63130, USA
| | - Hani S Zaher
- Department of Biology, Washington University in St. Louis, One Brookings Drive, Campus Box 1137, St. Louis, MO, 63130, USA.
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84
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Chen F, Tang Q, Bian K, Humulock ZT, Yang X, Jost M, Drennan CL, Essigmann JM, Li D. Adaptive Response Enzyme AlkB Preferentially Repairs 1-Methylguanine and 3-Methylthymine Adducts in Double-Stranded DNA. Chem Res Toxicol 2016; 29:687-93. [PMID: 26919079 DOI: 10.1021/acs.chemrestox.5b00522] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The AlkB protein is a repair enzyme that uses an α-ketoglutarate/Fe(II)-dependent mechanism to repair alkyl DNA adducts. AlkB has been reported to repair highly susceptible substrates, such as 1-methyladenine and 3-methylcytosine, more efficiently in ss-DNA than in ds-DNA. Here, we tested the repair of weaker AlkB substrates 1-methylguanine and 3-methylthymine and found that AlkB prefers to repair them in ds-DNA. We also discovered that AlkB and its human homologues, ABH2 and ABH3, are able to repair the aforementioned adducts when the adduct is present in a mismatched base pair. These observations demonstrate the strong adaptability of AlkB toward repairing various adducts in different environments.
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Affiliation(s)
- Fangyi Chen
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Qi Tang
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Ke Bian
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Zachary T Humulock
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
| | - Xuedong Yang
- School of Pharmaceutical Science and Technology, Tianjin University , Tianjin 300072, P. R. China
| | | | | | | | - Deyu Li
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island , Kingston, Rhode Island 02881, United States
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85
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Qiao Y, Zhou B, Zhang M, Liu W, Han Z, Song C, Yu W, Yang Q, Wang R, Wang S, Shi S, Zhao R, Chai J, Chang J. A Novel Inhibitor of the Obesity-Related Protein FTO. Biochemistry 2016; 55:1516-22. [DOI: 10.1021/acs.biochem.6b00023] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Yan Qiao
- Pathophysiology
Department, Basic Medical College of Zhengzhou University, Zhengzhou 450001, PR China
| | - Bin Zhou
- School
of Life Sciences, Tsinghua University, Beijing 100084, PR China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China
| | - Meizi Zhang
- Space
Biology Research and Technology Center, Engineering Research Center
of Space Biology, China Academy of Space Technology, Beijing 100190, PR China
| | - Weijia Liu
- School
of Life Sciences, Tsinghua University, Beijing 100084, PR China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China
| | - Zhifu Han
- School
of Life Sciences, Tsinghua University, Beijing 100084, PR China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China
| | - Chuanjun Song
- College
of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Wenquan Yu
- College
of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Qinghua Yang
- College
of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Ruiyong Wang
- College
of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Shaomin Wang
- College
of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Shuai Shi
- College
of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, PR China
| | - Renbin Zhao
- Space
Biology Research and Technology Center, Engineering Research Center
of Space Biology, China Academy of Space Technology, Beijing 100190, PR China
| | - Jijie Chai
- School
of Life Sciences, Tsinghua University, Beijing 100084, PR China
- Tsinghua-Peking Center for Life Sciences, Beijing 100084, PR China
| | - Junbiao Chang
- Pathophysiology
Department, Basic Medical College of Zhengzhou University, Zhengzhou 450001, PR China
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86
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O'Brown ZK, Greer EL. N6-Methyladenine: A Conserved and Dynamic DNA Mark. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 945:213-246. [PMID: 27826841 DOI: 10.1007/978-3-319-43624-1_10] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
Chromatin, consisting of deoxyribonucleic acid (DNA) wrapped around histone proteins, facilitates DNA compaction and allows identical DNA codes to confer many different cellular phenotypes. This biological versatility is accomplished in large part by posttranslational modifications to histones and chemical modifications to DNA. These modifications direct the cellular machinery to expand or compact specific chromatin regions and mark regions of the DNA as important for cellular functions. While each of the four bases that make up DNA can be modified (Iyer et al. 2011), this chapter will focus on methylation of the sixth position on adenines (6mA), as this modification has been poorly characterized in recently evolved eukaryotes, but shows promise as a new conserved layer of epigenetic regulation. 6mA was previously thought to be restricted to unicellular organisms, but recent work has revealed its presence in metazoa. Here, we will briefly describe the history of 6mA, examine its evolutionary conservation, and evaluate the current methods for detecting 6mA. We will discuss the enzymes that bind and regulate this mark and finally examine known and potential functions of 6mA in eukaryotes.
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Affiliation(s)
- Zach Klapholz O'Brown
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.,Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Eric Lieberman Greer
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA. .,Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA.
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87
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Abstract
DNA N(6)-adenine methylation (N(6)-methyladenine; 6mA) in prokaryotes functions primarily in the host defence system. The prevalence and significance of this modification in eukaryotes had been unclear until recently. Here, we discuss recent publications documenting the presence of 6mA in Chlamydomonas reinhardtii, Drosophila melanogaster and Caenorhabditis elegans; consider possible roles for this DNA modification in regulating transcription, the activity of transposable elements and transgenerational epigenetic inheritance; and propose 6mA as a new epigenetic mark in eukaryotes.
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88
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Structural insight into substrate preference for TET-mediated oxidation. Nature 2015; 527:118-22. [PMID: 26524525 DOI: 10.1038/nature15713] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 09/10/2015] [Indexed: 12/19/2022]
Abstract
DNA methylation is an important epigenetic modification. Ten-eleven translocation (TET) proteins are involved in DNA demethylation through iteratively oxidizing 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). Here we show that human TET1 and TET2 are more active on 5mC-DNA than 5hmC/5fC-DNA substrates. We determine the crystal structures of TET2-5hmC-DNA and TET2-5fC-DNA complexes at 1.80 Å and 1.97 Å resolution, respectively. The cytosine portion of 5hmC/5fC is specifically recognized by TET2 in a manner similar to that of 5mC in the TET2-5mC-DNA structure, and the pyrimidine base of 5mC/5hmC/5fC adopts an almost identical conformation within the catalytic cavity. However, the hydroxyl group of 5hmC and carbonyl group of 5fC face towards the opposite direction because the hydroxymethyl group of 5hmC and formyl group of 5fC adopt restrained conformations through forming hydrogen bonds with the 1-carboxylate of NOG and N4 exocyclic nitrogen of cytosine, respectively. Biochemical analyses indicate that the substrate preference of TET2 results from the different efficiencies of hydrogen abstraction in TET2-mediated oxidation. The restrained conformation of 5hmC and 5fC within the catalytic cavity may prevent their abstractable hydrogen(s) adopting a favourable orientation for hydrogen abstraction and thus result in low catalytic efficiency. Our studies demonstrate that the substrate preference of TET2 results from the intrinsic value of its substrates at their 5mC derivative groups and suggest that 5hmC is relatively stable and less prone to further oxidation by TET proteins. Therefore, TET proteins are evolutionarily tuned to be less reactive towards 5hmC and facilitate the generation of 5hmC as a potentially stable mark for regulatory functions.
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89
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Conde J, Yoon JH, Roy Choudhury J, Prakash L, Prakash S. Genetic Control of Replication through N1-methyladenine in Human Cells. J Biol Chem 2015; 290:29794-800. [PMID: 26491020 DOI: 10.1074/jbc.m115.693010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Indexed: 11/06/2022] Open
Abstract
N1-methyl adenine (1-MeA) is formed in DNA by reaction with alkylating agents and naturally occurring methyl halides. The 1-MeA lesion impairs Watson-Crick base pairing and blocks normal DNA replication. Here we identify the translesion synthesis (TLS) DNA polymerases (Pols) required for replicating through 1-MeA in human cells and show that TLS through this lesion is mediated via three different pathways in which Pols ι and θ function in one pathway and Pols η and ζ, respectively, function in the other two pathways. Our biochemical studies indicate that in the Polι/Polθ pathway, Polι would carry out nucleotide insertion opposite 1-MeA from which Polθ would extend synthesis. In the Polη pathway, this Pol alone would function at both the nucleotide insertion and extension steps of TLS, and in the third pathway, Polζ would extend from the nucleotide inserted opposite 1-MeA by an as yet unidentified Pol. Whereas by pushing 1-MeA into the syn conformation and by forming Hoogsteen base pair with the T residue, Polι would carry out TLS opposite 1-MeA, the ability of Polη to replicate through 1-MeA suggests that despite its need for Watson-Crick hydrogen bonding, Polη can stabilize the adduct in its active site. Remarkably, even though Pols η and ι are quite error-prone at inserting nucleotides opposite 1-MeA, TLS opposite this lesion in human cells occurs in a highly error-free fashion. This suggests that the in vivo fidelity of TLS Pols is regulated by factors such as post-translational modifications, protein-protein interactions, and possibly others.
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Affiliation(s)
- Juan Conde
- From the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1061
| | - Jung-Hoon Yoon
- From the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1061
| | - Jayati Roy Choudhury
- From the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1061
| | - Louise Prakash
- From the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1061
| | - Satya Prakash
- From the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, Texas 77555-1061
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90
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He W, Zhou B, Liu W, Zhang M, Shen Z, Han Z, Jiang Q, Yang Q, Song C, Wang R, Niu T, Han S, Zhang L, Wu J, Guo F, Zhao R, Yu W, Chai J, Chang J. Identification of A Novel Small-Molecule Binding Site of the Fat Mass and Obesity Associated Protein (FTO). J Med Chem 2015; 58:7341-8. [PMID: 26314339 DOI: 10.1021/acs.jmedchem.5b00702] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
N-(5-Chloro-2,4-dihydroxyphenyl)-1-phenylcyclobutanecarboxamide (N-CDPCB, 1a) is found to be an inhibitor of the fat mass and obesity associated protein (FTO). The crystal structure of human FTO with 1a reveals a novel binding site for the FTO inhibitor and defines the molecular basis for recognition by FTO of the inhibitor. The identification of the new binding site offers new opportunities for further development of selective and potent inhibitors of FTO, which is expected to provide information concerning novel therapeutic targets for treatment of obesity or obesity-associated diseases.
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Affiliation(s)
- Wu He
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Bin Zhou
- School of Life Sciences, Tsinghua University , Beijing 100084, PR China.,Tsinghua-Peking Center for Life Sciences , Beijing 100084, PR China
| | - Weijia Liu
- School of Life Sciences, Tsinghua University , Beijing 100084, PR China.,Tsinghua-Peking Center for Life Sciences , Beijing 100084, PR China
| | - Meizi Zhang
- Space Biology Research and Technology Center, Engineering Research Center of Space Biology, China Academy of Space Technology , Beijing 100190, PR China
| | - Zhenhua Shen
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Zhifu Han
- School of Life Sciences, Tsinghua University , Beijing 100084, PR China.,Tsinghua-Peking Center for Life Sciences , Beijing 100084, PR China
| | - Qingwei Jiang
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Qinghua Yang
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China.,Collaborative Innovation Center of New Drug Research and Safety Evaluation , Henan Province, Zhengzhou 450001, PR China
| | - Chuanjun Song
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Ruiyong Wang
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Tianhui Niu
- School of Life Sciences, Tsinghua University , Beijing 100084, PR China.,Tsinghua-Peking Center for Life Sciences , Beijing 100084, PR China
| | - Shengna Han
- Basic Medical College, Zhengzhou University , Zhengzhou 450001, PR China
| | - Lirong Zhang
- Basic Medical College, Zhengzhou University , Zhengzhou 450001, PR China
| | - Jie Wu
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Feima Guo
- Space Biology Research and Technology Center, Engineering Research Center of Space Biology, China Academy of Space Technology , Beijing 100190, PR China
| | - Renbin Zhao
- Space Biology Research and Technology Center, Engineering Research Center of Space Biology, China Academy of Space Technology , Beijing 100190, PR China
| | - Wenquan Yu
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China
| | - Jijie Chai
- School of Life Sciences, Tsinghua University , Beijing 100084, PR China.,Tsinghua-Peking Center for Life Sciences , Beijing 100084, PR China
| | - Junbiao Chang
- College of Chemistry and Molecular Engineering, Zhengzhou University , Zhengzhou 450001, PR China.,Collaborative Innovation Center of New Drug Research and Safety Evaluation , Henan Province, Zhengzhou 450001, PR China
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91
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Fedeles BI, Singh V, Delaney JC, Li D, Essigmann JM. The AlkB Family of Fe(II)/α-Ketoglutarate-dependent Dioxygenases: Repairing Nucleic Acid Alkylation Damage and Beyond. J Biol Chem 2015; 290:20734-20742. [PMID: 26152727 DOI: 10.1074/jbc.r115.656462] [Citation(s) in RCA: 271] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The AlkB family of Fe(II)- and α-ketoglutarate-dependent dioxygenases is a class of ubiquitous direct reversal DNA repair enzymes that remove alkyl adducts from nucleobases by oxidative dealkylation. The prototypical and homonymous family member is an Escherichia coli "adaptive response" protein that protects the bacterial genome against alkylation damage. AlkB has a wide variety of substrates, including monoalkyl and exocyclic bridged adducts. Nine mammalian AlkB homologs exist (ALKBH1-8, FTO), but only a subset functions as DNA/RNA repair enzymes. This minireview presents an overview of the AlkB proteins including recent data on homologs, structural features, substrate specificities, and experimental strategies for studying DNA repair by AlkB family proteins.
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Affiliation(s)
- Bogdan I Fedeles
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Vipender Singh
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - James C Delaney
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Deyu Li
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
| | - John M Essigmann
- Departments of Chemistry and Biological Engineering and the Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139.
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92
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Ougland R, Rognes T, Klungland A, Larsen E. Non-homologous functions of the AlkB homologs. J Mol Cell Biol 2015; 7:494-504. [PMID: 26003568 DOI: 10.1093/jmcb/mjv029] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 02/26/2015] [Indexed: 12/22/2022] Open
Abstract
The DNA repair enzyme AlkB was identified in E. coli more than three decades ago. Since then, nine mammalian homologs, all members of the superfamily of alpha-ketoglutarate and Fe(II)-dependent dioxygenases, have been identified (designated ALKBH1-8 and FTO). While E. coli AlkB serves as a DNA repair enzyme, only two mammalian homologs have been confirmed to repair DNA in vivo. The other mammalian homologs have remarkably diverse substrate specificities and biological functions. Substrates recognized by the different AlkB homologs comprise erroneous methyl- and etheno adducts in DNA, unique wobble uridine modifications in certain tRNAs, methylated adenines in mRNA, and methylated lysines on proteins. The phenotypes of organisms lacking or overexpressing individual AlkB homologs include obesity, severe sensitivity to inflammation, infertility, growth retardation, and multiple malformations. Here we review the present knowledge of the mammalian AlkB homologs and their implications for human disease and development.
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Affiliation(s)
- Rune Ougland
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway Department of Anesthesiology, Division of Emergencies and Critical Care, Oslo University Hospital, The Norwegian Radium Hospital, 0310 Oslo, Norway
| | - Torbjørn Rognes
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway Department of Informatics, University of Oslo, 0316 Oslo, Norway
| | - Arne Klungland
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway Faculty of Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Elisabeth Larsen
- Clinic for Diagnostics and Intervention and Institute of Medical Microbiology, Oslo University Hospital, Rikshospitalet, 0027 Oslo, Norway
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93
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Müller TA, Hausinger RP. AlkB and Its Homologues – DNA Repair and Beyond. 2-OXOGLUTARATE-DEPENDENT OXYGENASES 2015. [DOI: 10.1039/9781782621959-00246] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
AlkB is an Fe(ii)/2-oxoglutarate-dependent dioxygenase that is part of the adaptive response to alkylating agents in Escherichia coli. AlkB hydroxylates a wide variety of alkylated DNA bases producing unstable intermediates which decompose to restore the non-alkylated bases. Homologues exist in other bacteria, metazoa (e.g. nine in humans), plants and viruses, but not in archaea, with many catalysing the same oxidative demethylation reactions as for AlkB. The mammalian enzymes Alkbh2 and Alkbh3 catalyse direct DNA repair, Alkbh5 and FTO (Alkbh9) are RNA demethylases, and Alkbh8 is used to synthesize a tRNA, while the remaining mammalian homologues have alternative functions. Alkbh1 is an apurinic/apyrimidinic lyase in addition to exhibiting demethylase activities, but no clear role for the Alkbh1 protein has emerged. Alkbh4 is involved in cell division and potentially demethylates actin, whereas the mitochondrial homologue Alkbh7 has a role in obesity; however, no enzymatic activity has been linked to Alkbh4 or Alkbh7. Here, we discuss AlkB as the ‘archetype’ of this class of hydroxylases, compare it to Alkbh2 and Alkbh3, and then briefly review the diverse (and largely unknown) functions of Alkbh1, Alkbh4, Alkbh6 and Alkbh7. Alkbh5, Alkbh8 and Alkbh9 (FTO) are described separately.
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Affiliation(s)
- Tina A. Müller
- Department of Microbiology and Molecular Genetics, Michigan State University East Lansing MI 48824 USA
| | - Robert P. Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University East Lansing MI 48824 USA
- Department of Biochemistry and Molecular Biology, Michigan State University East Lansing MI 48824 USA
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94
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Rossetti G, Dans PD, Gomez-Pinto I, Ivani I, Gonzalez C, Orozco M. The structural impact of DNA mismatches. Nucleic Acids Res 2015; 43:4309-21. [PMID: 25820425 PMCID: PMC4417165 DOI: 10.1093/nar/gkv254] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 12/17/2014] [Accepted: 03/12/2015] [Indexed: 11/13/2022] Open
Abstract
The structure and dynamics of all the transversion and transition mismatches in three different DNA environments have been characterized by molecular dynamics simulations and NMR spectroscopy. We found that the presence of mismatches produced significant local structural alterations, especially in the case of purine transversions. Mismatched pairs often show promiscuous hydrogen bonding patterns, which interchange among each other in the nanosecond time scale. This therefore defines flexible base pairs, where breathing is frequent, and where distortions in helical parameters are strong, resulting in significant alterations in groove dimension. Even if the DNA structure is plastic enough to absorb the structural impact of the mismatch, local structural changes can be propagated far from the mismatch site, following the expected through-backbone and a previously unknown through-space mechanism. The structural changes related to the presence of mismatches help to understand the different susceptibility of mismatches to the action of repairing proteins.
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Affiliation(s)
- Giulia Rossetti
- Joint BSC-CRG-IRB Program on Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac, 10, Barcelona 08028, Spain Computational Biophysics, German Research School for Simulation Sciences (Joint venture of RWTH Aachen University and Forschungszentrum Jülich, Germany), D-52425 Jülich, Germany and Institute for Advanced Simulation IAS-5, Computational Biomedicine, Forschungszentrum Jülich, D-52425 Jülich, Germany Juelich Supercomputing Center (JSC), Forschungszentrum Jülich, Jülich, Germany
| | - Pablo D Dans
- Joint BSC-CRG-IRB Program on Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Irene Gomez-Pinto
- Joint BSC-CRG-IRB Program on Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac, 10, Barcelona 08028, Spain Instituto de Química Física Rocasolano, CSIC, C/Serrano 119, Madrid 28006, Spain
| | - Ivan Ivani
- Joint BSC-CRG-IRB Program on Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Carlos Gonzalez
- Instituto de Química Física Rocasolano, CSIC, C/Serrano 119, Madrid 28006, Spain
| | - Modesto Orozco
- Joint BSC-CRG-IRB Program on Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac, 10, Barcelona 08028, Spain Departament de Bioquímica i Biologia Molecular, Facultat de Biologia, Universitat de Barcelona, Avgda Diagonal 647, Barcelona 08028, Spain
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95
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Monakhova M, Ryazanova A, Hentschel A, Viryasov M, Oretskaya T, Friedhoff P, Kubareva E. Chromatographic isolation of the functionally active MutS protein covalently linked to deoxyribonucleic acid. J Chromatogr A 2015; 1389:19-27. [PMID: 25746757 DOI: 10.1016/j.chroma.2015.02.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 02/10/2015] [Accepted: 02/16/2015] [Indexed: 12/11/2022]
Abstract
DNA metabolism is based on formation of different DNA-protein complexes which can adopt various conformations. To characterize functioning of such complexes, one needs a solution-based technique which allows fixing a complex in a certain transient conformation. The crosslinking approach is a popular tool for such studies. However, it is under debate if the protein components retain their natural activities in the resulting crosslinked complexes. In the present work we demonstrate the possibility of obtaining pure DNA conjugate with functionally active protein using as example MutS protein from Escherichia coli mismatch repair system. A conjugate of a chemically modified mismatch-containing DNA duplex with MutS is fixed by thiol-disulfide exchange reaction. To perform a reliable test of the protein activity in the conjugate, such conjugate must be thoroughly separated from the uncrosslinked protein and DNA prior to the test. In the present work, we employ anion exchange chromatography for this purpose for the first time and demonstrate this technique to be optimal for the conjugate purification. The activity test is a FRET-based detection of DNA unbending. We show experimentally that MutS in the conjugate retains its ability to unbend DNA in response to ATP addition and find out for the first time that the DNA unbending rate increases with increasing ATP concentration. Since the crosslinked complexes contain active MutS protein, they can be used in further experiments to investigate MutS interactions with other proteins of the mismatch repair system.
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Affiliation(s)
- Mayya Monakhova
- Chemistry Department and A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia
| | - Alexandra Ryazanova
- Chemistry Department and A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia
| | - Andreas Hentschel
- Institute for Biochemistry, FB 08, Justus Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Mikhail Viryasov
- Chemistry Department and A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia.
| | - Tatiana Oretskaya
- Chemistry Department and A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia
| | - Peter Friedhoff
- Institute for Biochemistry, FB 08, Justus Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany
| | - Elena Kubareva
- Chemistry Department and A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Leninskie Gory 1, 119991 Moscow, Russia
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96
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Huang Y, Yan J, Li Q, Li J, Gong S, Zhou H, Gan J, Jiang H, Jia GF, Luo C, Yang CG. Meclofenamic acid selectively inhibits FTO demethylation of m6A over ALKBH5. Nucleic Acids Res 2015; 43:373-84. [PMID: 25452335 PMCID: PMC4288171 DOI: 10.1093/nar/gku1276] [Citation(s) in RCA: 442] [Impact Index Per Article: 49.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 11/18/2014] [Accepted: 11/20/2014] [Indexed: 12/21/2022] Open
Abstract
Two human demethylases, the fat mass and obesity-associated (FTO) enzyme and ALKBH5, oxidatively demethylate abundant N(6)-methyladenosine (m(6)A) residues in mRNA. Achieving a method for selective inhibition of FTO over ALKBH5 remains a challenge, however. Here, we have identified meclofenamic acid (MA) as a highly selective inhibitor of FTO. MA is a non-steroidal, anti-inflammatory drug that mechanistic studies indicate competes with FTO binding for the m(6)A-containing nucleic acid. The structure of FTO/MA has revealed much about the inhibitory function of FTO. Our newfound understanding, revealed herein, of the part of the nucleotide recognition lid (NRL) in FTO, for example, has helped elucidate the principles behind the selectivity of FTO over ALKBH5. Treatment of HeLa cells with the ethyl ester form of MA (MA2) has led to elevated levels of m(6)A modification in mRNA. Our collective results highlight the development of functional probes of the FTO enzyme that will (i) enable future biological studies and (ii) pave the way for the rational design of potent and specific inhibitors of FTO for use in medicine.
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Affiliation(s)
- Yue Huang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jingli Yan
- 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
| | - Qi Li
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jiafei Li
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Shouzhe Gong
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Hu Zhou
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Jianhua Gan
- School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Hualiang Jiang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Gui-Fang 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
| | - Cheng Luo
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Cai-Guang Yang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
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97
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Abstract
Mammalian messenger RNA (mRNA) and long noncoding RNA (lncRNA) contain tens of thousands of posttranscriptional chemical modifications. Among these, the N(6)-methyl-adenosine (m(6)A) modification is the most abundant and can be removed by specific mammalian enzymes. m(6)A modification is recognized by families of RNA binding proteins that affect many aspects of mRNA function. mRNA/lncRNA modification represents another layer of epigenetic regulation of gene expression, analogous to DNA methylation and histone modification.
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98
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Toh JDW, Sun L, Lau LZM, Tan J, Low JJA, Tang CWQ, Cheong EJY, Tan MJH, Chen Y, Hong W, Gao YG, Woon ECY. A strategy based on nucleotide specificity leads to a subfamily-selective and cell-active inhibitor of N6-methyladenosine demethylase FTO. Chem Sci 2015; 6:112-122. [PMID: 28553460 PMCID: PMC5424463 DOI: 10.1039/c4sc02554g] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 09/15/2014] [Indexed: 01/30/2023] Open
Abstract
The AlkB family of nucleic acid demethylases are of intense biological and medical interest because of their roles in nucleic acid repair and epigenetic modification. However their functional and molecular mechanisms are unclear, hence, there is strong interest in developing selective inhibitors for them. Here we report the identification of key residues within the nucleotide-binding sites of the AlkB subfamilies that likely determine their substrate specificity. We further provide proof of principle that a strategy exploiting these inherent structural differences can enable selective and potent inhibition of the AlkB subfamilies. This is demonstrated by the first report of a subfamily-selective and cell-active FTO inhibitor 12. The distinct selectivity of 12 for FTO against other AlkB subfamilies and 2OG oxygenases shall be of considerable interest with regards to its potential use as a functional probe. The strategy outlined here is likely applicable to other AlkB subfamilies, and, more widely, to other 2OG oxygenases.
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Affiliation(s)
- Joel D W Toh
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
- Institute of Molecular and Cell Biology , 61 Biopolis Drive, Proteos , 138673 , Singapore
| | - Lingyi Sun
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Lisa Z M Lau
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Jackie Tan
- School of Biological Sciences , Nanyang Technological University , 60 Nanyang Drive , 637551 , Singapore .
| | - Joanne J A Low
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Colin W Q Tang
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Eleanor J Y Cheong
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Melissa J H Tan
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
| | - Yun Chen
- School of Biological Sciences , Nanyang Technological University , 60 Nanyang Drive , 637551 , Singapore .
| | - Wanjin Hong
- Institute of Molecular and Cell Biology , 61 Biopolis Drive, Proteos , 138673 , Singapore
| | - Yong-Gui Gao
- Institute of Molecular and Cell Biology , 61 Biopolis Drive, Proteos , 138673 , Singapore
- School of Biological Sciences , Nanyang Technological University , 60 Nanyang Drive , 637551 , Singapore .
| | - Esther C Y Woon
- Department of Pharmacy , National University of Singapore , 18 Science Drive 4 , 117543 , Singapore . ; ; Tel: +65 6516 2932
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99
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Yufa R, Krylova SM, Bruce C, Bagg EA, Schofield CJ, Krylov SN. Emulsion PCR significantly improves nonequilibrium capillary electrophoresis of equilibrium mixtures-based aptamer selection: allowing for efficient and rapid selection of aptamer to unmodified ABH2 protein. Anal Chem 2014; 87:1411-9. [PMID: 25495441 DOI: 10.1021/ac5044187] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM), a homogeneous approach to select DNA aptamers, is among the most efficient partitioning techniques. In contrast with surface-based systematic evolution of ligands by exponential enrichment (SELEX) approaches, the ability of NECEEM to select aptamers to unmodified proteins in solution is preferable for identifying aptamers for eventual in vivo use. The high stringency and low sample volumes of NECEEM, although generally beneficial, can result in binding of very few aptamers, requiring highly efficient amplification to propagate them. When amplified with standard PCR, detectable library enrichment can fail due to the fast conversion of the aptamers into byproducts and preferential amplification of nonbinders. As an alternative, we proposed the use of emulsion PCR (ePCR), which is known to reduce byproduct formation, as a PCR mode for coupling with NECEEM partitioning. For the first time, we tested the advantages of ePCR in NECEEM-based aptamer selection to a medically relevant DNA repair enzyme, ABH2. We report that the combination of ePCR with NECEEM allowed for the selection of aptamers in the first three rounds of SELEX, while SELEX with conventional PCR failed in a number of attempts. Selected aptamers to an unmodified ABH2 protein have potential use in diagnostics and as leads for anticancer cotherapies, used as enhancements of alkylating agents in chemotherapy.
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Affiliation(s)
- Roman Yufa
- Department of Chemistry and Centre for Research on Biomolecular Interactions, York University , Toronto, Ontario M3J 1P3, Canada
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100
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Silvestrov P, Müller TA, Clark KN, Hausinger RP, Cisneros GA. Homology modeling, molecular dynamics, and site-directed mutagenesis study of AlkB human homolog 1 (ALKBH1). J Mol Graph Model 2014; 54:123-30. [PMID: 25459764 DOI: 10.1016/j.jmgm.2014.10.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 10/16/2014] [Accepted: 10/21/2014] [Indexed: 02/03/2023]
Abstract
The ability to repair DNA is important for the conservation of genetic information of living organisms. Cells have a number of ways to restore damaged DNA, such as direct DNA repair, base excision repair, and nucleotide excision repair. One of the proteins that can perform direct repair of DNA bases is Escherichia coli AlkB. In humans, there are 9 identified AlkB homologs, including AlkB homolog 1 (ALKBH1). Many of these proteins catalyze the direct oxidative dealkylation of DNA and RNA bases and, as such, have an important role in repairing DNA from damage induced by alkylating agents. In addition to the dealkylase activity, ALKBH1 can also function as an apyrimidinic/apurinic lyase and was proposed to have a distinct lyase active site. To our knowledge, no crystal structure or complete homology model of ALKBH1 protein is available. In this study, we have used homology modeling to predict the structure of ALKBH1 based on AlkB and Duffy-binding-like domain crystal structures as templates. Molecular dynamics simulations were subsequently performed on the predicted structure of ALKBH1. The positions of two disulfide bonds or a zinc-finger motif and a disulfide bond were predicted and the importance of these features was tested by mutagenesis. Possible locations for the lyase active site are proposed based on the analysis of our predicted structures and previous experimental results.
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Affiliation(s)
- Pavel Silvestrov
- Department of Chemistry, Wayne State University, Detroit, MI 48202, United States
| | - Tina A Müller
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - Kristen N Clark
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - Robert P Hausinger
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, United States
| | - G Andrés Cisneros
- Department of Chemistry, Wayne State University, Detroit, MI 48202, United States.
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