1
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Kaur R, Nikkel DJ, Wetmore SD. Mechanism of Nucleic Acid Phosphodiester Bond Cleavage by Human Endonuclease V: MD and QM/MM Calculations Reveal a Versatile Metal Dependence. J Phys Chem B 2024; 128:9455-9469. [PMID: 39359137 DOI: 10.1021/acs.jpcb.4c05846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2024]
Abstract
Human endonuclease V (EndoV) catalytically removes deaminated nucleobases by cleaving the phosphodiester bond as part of RNA metabolism. Despite being implicated in several diseases (cancers, cardiovascular diseases, and neurological disorders) and potentially being a useful tool in biotechnology, details of the human EndoV catalytic pathway remain unclear due to limited experimental information beyond a crystal structure of the apoenzyme and select mutational data. Since a mechanistic understanding is critical for further deciphering the central roles and expanding applications of human EndoV in medicine and biotechnology, molecular dynamics (MD) simulations and quantum mechanics/molecular mechanics (QM/MM) calculations were used to unveil the atomistic details of the catalytic pathway. Due to controversies surrounding the number of metals required for nuclease activity, enzyme-substrate models with different numbers of active site metals and various metal-substrate binding configurations were built based on structural data for other nucleases. Subsequent MD simulations revealed the structure and stability of the human EndoV-substrate complex for a range of active site metal binding architectures. Four unique pathways were then characterized using QM/MM that vary in metal number (one versus two) and modes of substrate coordination [direct versus indirect (water-mediated)], with several mechanisms being fully consistent with experimental structural, kinetic, and mutational data for related nucleases, including members of the EndoV family. Beyond uncovering key roles for several active site amino acids (D240 and K155), our calculations highlight that while one metal is essential for human EndoV activity, the enzyme can benefit from using two metals due to the presence of two suitable metal binding sites. By directly comparing one- versus two-metal-mediated P-O bond cleavage reactions within the confines of the same active site, our work brings a fresh perspective to the "number of metals" controversy.
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Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge T1K 3M4, Alberta, Canada
| | - Dylan J Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge T1K 3M4, Alberta, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge T1K 3M4, Alberta, Canada
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2
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Kaur R, Frederickson A, Wetmore SD. Elucidation of the catalytic mechanism of a single-metal dependent homing endonuclease using QM and QM/MM approaches: the case study of I- PpoI. Phys Chem Chem Phys 2024; 26:8919-8931. [PMID: 38426850 DOI: 10.1039/d3cp06201e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Homing endonucleases (HEs) are highly specific DNA cleaving enzymes, with I-PpoI having been suggested to use a single metal to accelerate phosphodiester bond cleavage. Although an I-PpoI mechanism has been proposed based on experimental structural data, no consensus has been reached regarding the roles of the metal or key active site amino acids. This study uses QM cluster and QM/MM calculations to provide atomic-level details of the I-PpoI catalytic mechanism. Minimal QM cluster and large-scale QM/MM models demonstrate that the experimentally-proposed pathway involving direct Mg2+ coordination to the substrate coupled with leaving group protonation through a metal-activated water is not feasible due to an inconducive I-PpoI active site alignment. Despite QM cluster models of varying size uncovering a pathway involving leaving group protonation by a metal-activated water, indirect (water-mediated) metal coordination to the substrate is required to afford this pathway, which renders this mechanism energetically infeasible. Instead, QM cluster models reveal that the preferred pathway involves direct Mg2+-O3' coordination to stabilize the charged substrate and assist leaving group departure, while H98 activates the water nucleophile. These calculations also underscore that both catalytic residues that directly interact with the substrate and secondary amino acids that position or stabilize these residues are required for efficient catalysis. QM/MM calculations on the solvated enzyme-DNA complex verify the preferred mechanism, which is fully consistent with experimental kinetic, structural, and mutational data. The fundamental understanding of the I-PpoI mechanism of action, gained from the present work can be used to further explore potential uses of this enzyme in biotechnology and medicine, and direct future computational investigations of other members of the understudied HE family.
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Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
| | - Angela Frederickson
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.
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3
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Kaur R, Wetmore SD. Is Metal Stabilization of the Leaving Group Required or Can Lysine Facilitate Phosphodiester Bond Cleavage in Nucleic Acids? A Computational Study of EndoV. J Chem Inf Model 2024; 64:944-959. [PMID: 38253321 DOI: 10.1021/acs.jcim.3c01775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Endonuclease V (EndoV) is a single-metal-dependent enzyme that repairs deaminated DNA nucleobases in cells by cleaving the phosphodiester bond, and this enzyme has proven to be a powerful tool in biotechnology and medicine. The catalytic mechanism used by EndoV must be understood to design new disease detection and therapeutic solutions and further exploit the enzyme in interdisciplinary applications. This study has used a mixed molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) approach to compare eight distinct catalytic pathways and provides the first proposed mechanism for bacterial EndoV. The calculations demonstrate that mechanisms involving either direct or indirect metal coordination to the leaving group of the substrate previously proposed for other nucleases are unlikely for EndoV, regardless of the general base (histidine, aspartate, and substrate phosphate moiety). Instead, distinct catalytic pathways are characterized for EndoV that involve K139 stabilizing the leaving group, a metal-coordinated water stabilizing the transition structure, and either H214 or a substrate phosphate group activating the water nucleophile. In silico K139A and H214A mutational results support the newly proposed roles of these residues. Although this is a previously unseen combination of general base, general acid, and metal-binding architecture for a one-metal-dependent endonuclease, our proposed catalytic mechanisms are fully consistent with experimental kinetic, structural, and mutational data. In addition to substantiating a growing body of literature, suggesting that one metal is enough to catalyze P-O bond cleavage in nucleic acids, this new fundamental understanding of the catalytic function will promote the exploration of new and improved applications of EndoV.
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Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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4
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Shan Z, Ghadirian N, Lyumkis D, Horton NC. Pretransition state and apo structures of the filament-forming enzyme SgrAI elucidate mechanisms of activation and substrate specificity. J Biol Chem 2022; 298:101760. [PMID: 35202658 PMCID: PMC8960973 DOI: 10.1016/j.jbc.2022.101760] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 12/01/2022] Open
Abstract
Enzyme filamentation is a widespread phenomenon that mediates enzyme regulation and function. For the filament-forming sequence-specific DNA endonuclease SgrAI, the process of filamentation both accelerates its DNA cleavage activity and expands its DNA sequence specificity, thus allowing for many additional DNA sequences to be rapidly cleaved. Both outcomes-the acceleration of DNA cleavage and the expansion of sequence specificity-are proposed to regulate critical processes in bacterial innate immunity. However, the mechanistic bases underlying these events remain unclear. Herein, we describe two new structures of the SgrAI enzyme that shed light on its catalytic function. First, we present the cryo-EM structure of filamentous SgrAI bound to intact primary site DNA and Ca2+ resolved to ∼2.5 Å within the catalytic center, which represents the trapped enzyme-DNA complex prior to the DNA cleavage reaction. This structure reveals important conformational changes that contribute to the catalytic mechanism and the binding of a second divalent cation in the enzyme active site, which is expected to contribute to increased DNA cleavage activity of SgrAI in the filamentous state. Second, we present an X-ray crystal structure of DNA-free (apo) SgrAI resolved to 2.0 Å resolution, which reveals a disordered loop involved in DNA recognition. Collectively, these multiple new observations clarify the mechanism of expansion of DNA sequence specificity of SgrAI, including the indirect readout of sequence-dependent DNA structure, changes in protein-DNA interactions, and the disorder-to-order transition of a crucial DNA recognition element.
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Affiliation(s)
- Zelin Shan
- Laboratory of Genetics, The Salk Institute of Biological Sciences, La Jolla, California, USA
| | - Niloofar Ghadirian
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Dmitry Lyumkis
- Laboratory of Genetics, The Salk Institute of Biological Sciences, La Jolla, California, USA; Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.
| | - Nancy C Horton
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, Arizona, USA.
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5
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Comparative Analysis of Exo- and Endonuclease Activities of APE1-like Enzymes. Int J Mol Sci 2022; 23:ijms23052869. [PMID: 35270011 PMCID: PMC8911113 DOI: 10.3390/ijms23052869] [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: 02/16/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/05/2022] Open
Abstract
Apurinic/apyrimidinic (AP)-endonucleases are multifunctional enzymes that are required for cell viability. AP-endonucleases incise DNA 5′ to an AP-site; can recognize and process some damaged nucleosides; and possess 3′-phosphodiesterase, 3′-phosphatase, and endoribonuclease activities. To elucidate the mechanism of substrate cleavage in detail, we analyzed the effect of mono- and divalent metal ions on the exo- and endonuclease activities of four homologous APE1-like endonucleases (from an insect (Rrp1), amphibian (xAPE1), fish (zAPE1), and from humans (hAPE1)). It was found that the enzymes had similar patterns of dependence on metal ions’ concentrations in terms of AP-endonuclease activity, suggesting that the main biological function (AP-site cleavage) was highly conserved among evolutionarily distant species. The efficiency of the 3′-5′ exonuclease activity was the highest in hAPE1 among these enzymes. In contrast, the endoribonuclease activity of the enzymes could be ranked as hAPE1 ≈ zAPE1 ≤ xAPE1 ≤ Rrp1. Taken together, the results revealed that the tested enzymes differed significantly in their capacity for substrate cleavage, even though the most important catalytic and substrate-binding amino acid residues were conserved. It can be concluded that substrate specificity and cleavage efficiency were controlled by factors external to the catalytic site, e.g., the N-terminal domain of these enzymes.
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6
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Kuznetsova AA, Gavrilova AA, Novopashina DS, Fedorova OS, Kuznetsov NA. Mutational and Kinetic Analysis of APE1 Endoribonuclease Activity. Mol Biol 2021; 55:211-224. [PMID: 33948042 PMCID: PMC8083922 DOI: 10.1134/s0026893321020102] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 12/20/2022]
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) participates in the DNA repair system. It is believed that the main biological function of APE1 is Mg2+-dependent hydrolysis of AP-sites in DNA. On the base of structural data, kinetic studies, and mutation analysis, the key stages of APE1 interaction with damaged DNA were established. It has been shown recently that APE1 can act as an endoribonuclease that catalyzes mRNA hydrolysis at certain pyrimidine–purine sites and thus controls the level of certain transcripts. In addition, the presence of Mg2+ ions was shown to be not required for the endoribonuclease activity of APE1, in contrast to the AP-endonuclease activity. This indicates differences in mechanisms of APE1 catalysis on RNA and DNA substrates, but the reasons for these differences remain unclear. Here, the analysis of endoribonuclease hydrolysis of model RNA substrates with wild type APE1 enzyme and its mutant forms Y171F, R177F, R181A, D210N, N212A, T268D, M270A, and D308A, was performed. It was shown that mutation of Asn212, Asp210, and Tyr171 residues leads to the decrease of AP-endonuclease activity while endoribonuclease activity is retained. Also, T268D and M270A APE1 mutants lose specificity to pyrimidine–purine sequences. R177F and R181A did not show a significant decrease in enzyme activity, whereas D308A demonstrated a decrease of endoribonuclease activity.
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Affiliation(s)
- A A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - A A Gavrilova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia.,Novosibirsk National Research State University, 630090 Novosibirsk, Russia
| | - D S Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - O S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
| | - N A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, 630090 Novosibirsk, Russia
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7
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Davletgildeeva AT, Ishchenko AA, Saparbaev M, Fedorova OS, Kuznetsov NA. The Enigma of Substrate Recognition and Catalytic Efficiency of APE1-Like Enzymes. Front Cell Dev Biol 2021; 9:617161. [PMID: 33842455 PMCID: PMC8033172 DOI: 10.3389/fcell.2021.617161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/22/2021] [Indexed: 11/13/2022] Open
Abstract
Despite significant achievements in the elucidation of the nature of protein-DNA contacts that control the specificity of nucleotide incision repair (NIR) by apurinic/apyrimidinic (AP) endonucleases, the question on how a given nucleotide is accommodated by the active site of the enzyme remains unanswered. Therefore, the main purpose of our study was to compare kinetics of conformational changes of three homologous APE1-like endonucleases (insect Drosophila melanogaster Rrp1, amphibian Xenopus laevis xAPE1, and fish Danio rerio zAPE1) during their interaction with various damaged DNA substrates, i.e., DNA containing an F-site (an uncleavable by DNA-glycosylases analog of an AP-site), 1,N6-ethenoadenosine (εA), 5,6-dihydrouridine (DHU), uridine (U), or the α-anomer of adenosine (αA). Pre-steady-state analysis of fluorescence time courses obtained for the interaction of the APE1-like enzymes with DNA substrates containing various lesions allowed us to outline a model of substrate recognition by this class of enzymes. It was found that the differences in rates of DNA substrates’ binding do not lead to significant differences in the cleavage efficiency of DNA containing a damaged base. The results suggest that the formation of enzyme–substrate complexes is not the key factor that limits enzyme turnover; the mechanisms of damage recognition and cleavage efficacy are related to fine conformational tuning inside the active site.
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Affiliation(s)
- Anastasiia T Davletgildeeva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Alexander A Ishchenko
- Group "Mechanisms of DNA Repair and Carcinogenesis", Equipe Labellisée LIGUE 2016, CNRS UMR 9019, Université Paris-Saclay, Villejuif, France
| | - Murat Saparbaev
- Group "Mechanisms of DNA Repair and Carcinogenesis", Equipe Labellisée LIGUE 2016, CNRS UMR 9019, Université Paris-Saclay, Villejuif, France
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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Ognik K, Konieczka P, Stępniowska A, Jankowski J. Oxidative and Epigenetic Changes and Gut Permeability Response in Early-Treated Chickens with Antibiotic or Probiotic. Animals (Basel) 2020; 10:E2204. [PMID: 33255575 PMCID: PMC7760912 DOI: 10.3390/ani10122204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/02/2020] [Accepted: 11/20/2020] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to compare the effect of the use of enrofloxacin and a probiotic containing Enterococcus faecium and Bacillus amyloliquefaciens strains in the first week of life of chickens on oxidative and epigenetic changes in molecules and intestinal integrity. The three treatments were as follows: the control group received no additive in the drinking water (GC); the second group (GP) received a probiotic preparation in the drinking water during the first five days of life, providing E. faecium strain 4a1713 at 1.0 × 107 CFU/L water and B. amyloliquefaciens 4b1822 at 1.0 × 107 CFU/L water, the third group (GA) received an antibiotic (enrofloxacin 0.5 mL/L water) in the drinking water during the first five days of life. The use of both enrofloxacin and a probiotic containing E. faecium and B. amyloliquefaciens strains in chickens' first week of life improved intestinal integrity and reduced inflammation and oxidative and epigenetic changes in the small intestine. This effect was evident both at 6 days of age and at the end of the rearing period.
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Affiliation(s)
- Katarzyna Ognik
- Department of Biochemistry and Toxicology, Faculty of Animal Science and Bioeconomy, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland;
| | - Paweł Konieczka
- Department of Poultry Science, Faculty of Animal Bioengineering, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, 10-719 Olsztyn, Poland; (P.K.); (J.J.)
| | - Anna Stępniowska
- Department of Biochemistry and Toxicology, Faculty of Animal Science and Bioeconomy, University of Life Sciences, Akademicka 13, 20-950 Lublin, Poland;
| | - Jan Jankowski
- Department of Poultry Science, Faculty of Animal Bioengineering, University of Warmia and Mazury in Olsztyn, Oczapowskiego 5, 10-719 Olsztyn, Poland; (P.K.); (J.J.)
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9
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The role of active-site amino acid residues in the cleavage of DNA and RNA substrates by human apurinic/apyrimidinic endonuclease APE1. Biochim Biophys Acta Gen Subj 2020; 1864:129718. [PMID: 32858086 DOI: 10.1016/j.bbagen.2020.129718] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/10/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Human apurinic/apyrimidinic endonuclease APE1 is one of participants of the DNA base excision repair pathway. APE1 processes AP-sites and many other types of DNA damage via hydrolysis of the phosphodiester bond on the 5' side of the lesion. APE1 also acts as an endoribonuclease, i.e., can cleave undamaged RNA. METHODS Using pre-steady-state kinetic analysis we examined the role of certain catalytically important amino acids in APE1 enzymatic pathway and described their involvement in the mechanism of the target nucleotide recognition. RESULTS Comparative analysis of the cleavage efficiency of damaged DNAs containing an abasic site, 5,6-dihydrouridine, or α-anomer of adenosine as well as 3'-5'-exonuclease degradation of undamaged DNA and endonuclease hydrolysis of RNA substrates by mutant APE1 enzymes containing a substitution of an active-site amino acid residue (D210N, N212A, T268D, M270A, or D308A) was performed. Detailed pre-steady-state kinetics of conformational changes of the enzyme and of DNA substrate molecules during recognition and cleavage of the abasic site were studied. CONCLUSIONS It was revealed that substitution T268D significantly disturbed initial DNA binding, whereas Asn212 is critical for the DNA-bending stage and catalysis. Substitution D210N increased the binding efficacy and blocked the catalytic reaction, but D308A decreased the binding efficacy owing to disruption of Mg2+ coordination. Finally, the substitution of Met270 also destabilized the enzyme-substrate complex but did not affect the catalytic reaction. SIGNIFICANCE It was found that the tested substitutions of the active-site amino acid residues affected different stages of the complex formation process as well as the catalytic reaction.
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10
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Jenkins K, Mateeva T, Szabó I, Melnik A, Picotti P, Csikász-Nagy A, Rosta E. Combining data integration and molecular dynamics for target identification in α-Synuclein-aggregating neurodegenerative diseases: Structural insights on Synaptojanin-1 (Synj1). Comput Struct Biotechnol J 2020; 18:1032-1042. [PMID: 32419904 PMCID: PMC7215115 DOI: 10.1016/j.csbj.2020.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/15/2020] [Accepted: 04/18/2020] [Indexed: 12/19/2022] Open
Abstract
Parkinson’s disease (PD), Alzheimer’s disease (AD) and Amyotrophic lateral sclerosis (ALS) are neurodegenerative diseases hallmarked by the formation of toxic protein aggregates. However, targeting these aggregates therapeutically have thus far shown no success. The treatment of AD has remained particularly problematic since no new drugs have been approved in the last 15 years. Therefore, novel therapeutic targets need to be identified and explored. Here, through the integration of genomic and proteomic data, a set of proteins with strong links to α-synuclein-aggregating neurodegenerative diseases was identified. We propose 17 protein targets that are likely implicated in neurodegeneration and could serve as potential targets. The human phosphatidylinositol 5-phosphatase synaptojanin-1, which has already been independently confirmed to be implicated in Parkinson’s and Alzheimer’s disease, was among those identified. Despite its involvement in PD and AD, structural aspects are currently missing at the molecular level. We present the first atomistic model of the 5-phosphatase domain of synaptojanin-1 and its binding to its substrate phosphatidylinositol 4,5-bisphosphate (PIP2). We determine structural information on the active site including membrane-embedded molecular dynamics simulations. Deficiency of charge within the active site of the protein is observed, which suggests that a second divalent cation is required to complete dephosphorylation of the substrate. The findings in this work shed light on the protein’s binding to phosphatidylinositol 4,5-bisphosphate (PIP2) and give additional insight for future targeting of the protein active site, which might be of interest in neurodegenerative diseases where synaptojanin-1 is overexpressed.
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Affiliation(s)
- Kirsten Jenkins
- Randall Division of Cell and Molecular Biophysics, Institute for Mathematical and Molecular Biomedicine, King's College London, London SE1 1UL, UK
| | - Teodora Mateeva
- Department of Chemistry, King's College London, London SE1 1DB, UK
| | - István Szabó
- Department of Chemistry, King's College London, London SE1 1DB, UK
| | - Andre Melnik
- Institute of Biochemistry, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Paola Picotti
- Institute of Biochemistry, Department of Biology, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Attila Csikász-Nagy
- Randall Division of Cell and Molecular Biophysics, Institute for Mathematical and Molecular Biomedicine, King's College London, London SE1 1UL, UK.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, 1083 Budapest, Hungary
| | - Edina Rosta
- Department of Chemistry, King's College London, London SE1 1DB, UK
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11
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Kuznetsova AA, Novopashina DS, Fedorova OS, Kuznetsov NA. Effect of the Substrate Structure and Metal Ions on the Hydrolysis of Undamaged RNA by Human AP Endonuclease APE1. Acta Naturae 2020; 12:74-85. [PMID: 32742730 PMCID: PMC7385091 DOI: 10.32607/actanaturae.10864] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/20/2020] [Indexed: 11/20/2022] Open
Abstract
Human apurinic/apyrimidinic (AP) endonuclease APE1 is one of the participants in the DNA base excision repair. The main biological function of APE1 is to hydrolyze the phosphodiester bond on the 5'-side of the AP sites. It has been shown recently that APE1 acts as an endoribonuclease and can cleave mRNA, thereby controlling the level of some transcripts. The sequences of CA, UA, and UG dinucleotides are the cleavage sites in RNA. In the present work, we performed a comparative analysis of the cleavage efficiency of model RNA substrates with short hairpin structures in which the loop size and the location of the pyrimidine-purine dinucleotide sequence were varied. The effect of various divalent metal ions and pH on the efficiency of the endoribonuclease reaction was analyzed. It was shown that site-specific hydrolysis of model RNA substrates depends on the spatial structure of the substrate. In addition, RNA cleavage occured in the absence of divalent metal ions, which proves that hydrolysis of DNA- and RNA substrates occurs via different catalytic mechanisms.
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Affiliation(s)
- A. A. Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
| | - D. S. Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
| | - O. S. Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
| | - N. A. Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
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12
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Aboelnga MM, Wetmore SD. Unveiling a Single-Metal-Mediated Phosphodiester Bond Cleavage Mechanism for Nucleic Acids: A Multiscale Computational Investigation of a Human DNA Repair Enzyme. J Am Chem Soc 2019; 141:8646-8656. [PMID: 31046259 DOI: 10.1021/jacs.9b03986] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Mohamed M. Aboelnga
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D. Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
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13
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Zhai J, Zhao M, Cao X, Li M, Zhao M. Metal-Ion-Responsive Bionanocomposite for Selective and Reversible Enzyme Inhibition. J Am Chem Soc 2018; 140:16925-16928. [DOI: 10.1021/jacs.8b10848] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Junqiu Zhai
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
- School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, China
| | - Muhua Zhao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Xiangjian Cao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Mengyuan Li
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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14
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Abstract
Before a deleterious DNA lesion can be replaced with its undamaged counterpart, the lesion must first be removed from the genome. This process of removing and replacing DNA lesions is accomplished by the careful coordination of several protein factors during DNA repair. One such factor is the multifunctional enzyme human apurinic/apyrimidinic endonuclease 1 (APE1), known best for its DNA backbone cleavage activity at AP sites during base excision repair (BER). APE1 preforms AP site incision with surgical precision and skill, by sculpting the DNA to place the cleavage site in an optimal position for nucleophilic attack within its compact protein active site. APE1, however, has demonstrated broad surgical expertise, and applies its DNA cleavage activity to a wide variety of DNA and RNA substrates. Here, we discuss what is known and unknown about APE1 cleavage mechanisms, focusing on structural and mechanistic considerations. Importantly, disruptions in the biological functions associated with APE1 are linked to numerous human maladies, including cancer and neurodegenerative diseases. The continued elucidation of APE1 mechanisms is required for rational drug design towards novel and strategic ways to target its associated repair pathways.
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Affiliation(s)
- Amy M Whitaker
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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15
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Batebi H, Dragelj J, Imhof P. Role of AP-endonuclease (Ape1) active site residues in stabilization of the reactant enzyme-DNA complex. Proteins 2018; 86:439-453. [PMID: 29344998 DOI: 10.1002/prot.25460] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 01/08/2018] [Accepted: 01/11/2018] [Indexed: 11/11/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (Ape1) is an important metal-dependent enzyme in the base excision repair mechanism, responsible for the backbone cleavage of abasic DNA through a phosphate hydrolysis reaction. Molecular dynamics simulations of Ape1 complexed to its substrate DNA performed for models containing 1 or 2 Mg2+ -ions as cofactor located at different positions show a complex with 1 metal ion bound on the leaving group site of the scissile phosphate to be the most likely reaction-competent conformation. Active-site residue His309 is found to be protonated based on pKa calculations and the higher conformational stability of the Ape1-DNA substrate complex compared to scenarios with neutral His309. Simulations of the D210N mutant further support the prevalence of protonated His309 and strongly suggest Asp210 as the general base for proton acceptance by a nucleophilic water molecule.
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Affiliation(s)
- Hossein Batebi
- Department of Physics, Institute of Theoretical Physics, Freie Universität Berlin, Arnimallee 14, Berlin, 14195, Germany
| | - Jovan Dragelj
- Department of Biology, Chemistry, and Pharmacy, Institute of Chemistry and Biochemistry, Freie Universität Berlin, Fabeckstrasse 36A, Berlin, 14195, Germany
| | - Petra Imhof
- Department of Physics, Institute of Theoretical Physics, Freie Universität Berlin, Arnimallee 14, Berlin, 14195, Germany
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16
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Le Coq J, Camacho-Artacho M, Velázquez JV, Santiveri CM, Gallego LH, Campos-Olivas R, Dölker N, Lietha D. Structural basis for interdomain communication in SHIP2 providing high phosphatase activity. eLife 2017; 6. [PMID: 28792888 PMCID: PMC5550278 DOI: 10.7554/elife.26640] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 07/24/2017] [Indexed: 12/17/2022] Open
Abstract
SH2-containing-inositol-5-phosphatases (SHIPs) dephosphorylate the 5-phosphate of phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) and play important roles in regulating the PI3K/Akt pathway in physiology and disease. Aiming to uncover interdomain regulatory mechanisms in SHIP2, we determined crystal structures containing the 5-phosphatase and a proximal region adopting a C2 fold. This reveals an extensive interface between the two domains, which results in significant structural changes in the phosphatase domain. Both the phosphatase and C2 domains bind phosphatidylserine lipids, which likely helps to position the active site towards its substrate. Although located distant to the active site, the C2 domain greatly enhances catalytic turnover. Employing molecular dynamics, mutagenesis and cell biology, we identify two distinct allosteric signaling pathways, emanating from hydrophobic or polar interdomain interactions, differentially affecting lipid chain or headgroup moieties of PI(3,4,5)P3. Together, this study reveals details of multilayered C2-mediated effects important for SHIP2 activity and points towards interesting new possibilities for therapeutic interventions. DOI:http://dx.doi.org/10.7554/eLife.26640.001
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Affiliation(s)
- Johanne Le Coq
- Cell Signalling and Adhesion Group, Spanish National Cancer Research Centre, Madrid, Spain
| | - Marta Camacho-Artacho
- Cell Signalling and Adhesion Group, Spanish National Cancer Research Centre, Madrid, Spain
| | - José Vicente Velázquez
- Cell Signalling and Adhesion Group, Spanish National Cancer Research Centre, Madrid, Spain
| | - Clara M Santiveri
- Spectroscopy and Nuclear Magnetic Resonance Unit, Spanish National Cancer Research Centre, Madrid, Spain
| | - Luis Heredia Gallego
- Cell Signalling and Adhesion Group, Spanish National Cancer Research Centre, Madrid, Spain
| | - Ramón Campos-Olivas
- Spectroscopy and Nuclear Magnetic Resonance Unit, Spanish National Cancer Research Centre, Madrid, Spain
| | - Nicole Dölker
- Structural Computational Biology Group, Structural Biology and Biocomputing Programme, Spanish National Cancer Research Centre, Madrid, Spain
| | - Daniel Lietha
- Cell Signalling and Adhesion Group, Spanish National Cancer Research Centre, Madrid, Spain
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17
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Dyrkheeva NS, Lebedeva NA, Lavrik OI. AP Endonuclease 1 as a Key Enzyme in Repair of Apurinic/Apyrimidinic Sites. BIOCHEMISTRY (MOSCOW) 2017; 81:951-67. [PMID: 27682167 DOI: 10.1134/s0006297916090042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) is one of the key participants in the DNA base excision repair system. APE1 hydrolyzes DNA adjacent to the 5'-end of an apurinic/apyrimidinic (AP) site to produce a nick with a 3'-hydroxyl group and a 5'-deoxyribose phosphate moiety. APE1 exhibits 3'-phosphodiesterase, 3'-5'-exonuclease, and 3'-phosphatase activities. APE1 was also identified as a redox factor (Ref-1). In this review, data on the role of APE1 in the DNA repair process and in other metabolic processes occurring in cells are analyzed as well as the interaction of this enzyme with DNA and other proteins participating in the repair system.
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Affiliation(s)
- N S Dyrkheeva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
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18
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Batebi H, Imhof P. Phosphodiester hydrolysis computed for cluster models of enzymatic active sites. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-2020-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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19
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Guerreiro PS, Estácio SG, Antunes F, Fernandes AS, Pinheiro PF, Costa JG, Castro M, Miranda JP, Guedes RC, Oliveira NG. Structure-based virtual screening toward the discovery of novel inhibitors of the DNA repair activity of the human apurinic/apyrimidinic endonuclease 1. Chem Biol Drug Des 2016; 88:915-925. [DOI: 10.1111/cbdd.12826] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 05/10/2016] [Accepted: 07/11/2016] [Indexed: 01/21/2023]
Affiliation(s)
- Patrícia S. Guerreiro
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
| | - Sílvia G. Estácio
- BioISI - Biosystems and Integrative Sciences Institute; Faculdade de Ciências; Universidade de Lisboa; Lisbon Portugal
| | - Fernando Antunes
- Departamento de Química e Bioquímica and Centro de Química e Bioquímica; Faculdade de Ciências; Universidade de Lisboa; Lisbon Portugal
| | - Ana S. Fernandes
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
- CBIOS; Universidade Lusófona Research Center for Biosciences and Health Technologies; Lisbon Portugal
| | - Pedro F. Pinheiro
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
- Centro de Química Estrutural (CQE); Instituto Superior Técnico; Universidade de Lisboa; Lisbon Portugal
| | - João G. Costa
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
- CBIOS; Universidade Lusófona Research Center for Biosciences and Health Technologies; Lisbon Portugal
| | - Matilde Castro
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
| | - Joana P. Miranda
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
| | - Rita C. Guedes
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
| | - Nuno G. Oliveira
- Research Institute for Medicines (iMed.ULisboa); Faculty of Pharmacy; Universidade de Lisboa; Lisbon Portugal
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20
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Kuznetsov NA, Kupryushkin MS, Abramova TV, Kuznetsova AA, Miroshnikova AD, Stetsenko DA, Pyshnyi DV, Fedorova OS. New oligonucleotide derivatives as unreactive substrate analogues and potential inhibitors of human apurinic/apyrimidinic endonuclease APE1. MOLECULAR BIOSYSTEMS 2016; 12:67-75. [PMID: 26548492 DOI: 10.1039/c5mb00692a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human apurinic/apyrimidinic endonuclease APE1 is one of the key enzymes of the base excision DNA repair system. The main biological function of APE1 is the hydrolysis of the phosphodiester bond on the 5'-side of an apurinic/apyrimidinic site (AP-site) to give the 5'-phosphate and 3'-hydroxyl group. It has long been known that AP-sites have mutagenic and cytotoxic effects and their accumulation in DNA is a potential hazard to the cell lifecycle. The structural and biochemical studies of APE1 are complicated by its high catalytic activity towards the AP-site and its cyclic or acyclic analogues. This work has focussed on the design, synthesis and analysis of oligonucleotide derivatives as potentially unreactive APE1 substrates. We have shown that the replacement of oxygen atoms in the phosphate group on the 5'-side from the AP-site analogue tetrahydrofuran (F) considerably decreases the rate of enzymatic hydrolysis of modified oligonucleotides. We have calculated that a N3'-P5' phosphoramidate linkage is hydrolysed about 30 times slower than the native phosphodiester bond while phosphorothioate or primary phosphoramidate linkages are cleaved more than three orders of magnitude slower. The value of IC50 of the oligonucleotide duplex containing a primary phosphoramidate linkage is 2.5 × 10(-7) M, which is in accordance with the APE1 association constant of DNA duplexes containing AP-sites. Thus, it is demonstrated that oligonucleotide duplexes with chemical modifications could be used as unreactive substrates and potential competitive inhibitors of APE1.
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Affiliation(s)
- Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Maxim S Kupryushkin
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Tatyana V Abramova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Alexandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Anastasia D Miroshnikova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia.
| | - Dmitry A Stetsenko
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Dmitrii V Pyshnyi
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia. and Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
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21
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Structural comparison of AP endonucleases from the exonuclease III family reveals new amino acid residues in human AP endonuclease 1 that are involved in incision of damaged DNA. Biochimie 2016; 128-129:20-33. [PMID: 27343627 DOI: 10.1016/j.biochi.2016.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 06/20/2016] [Indexed: 12/21/2022]
Abstract
Oxidatively damaged DNA bases are substrates for two overlapping repair pathways: DNA glycosylase-initiated base excision repair (BER) and apurinic/apyrimidinic (AP) endonuclease-initiated nucleotide incision repair (NIR). In the BER pathway, an AP endonuclease cleaves DNA at AP sites and 3'-blocking moieties generated by DNA glycosylases, whereas in the NIR pathway, the same AP endonuclease incises DNA 5' to an oxidized base. The majority of characterized AP endonucleases possess classic BER activities, and approximately a half of them can also have a NIR activity. At present, the molecular mechanism underlying DNA substrate specificity of AP endonucleases remains unclear mainly due to the absence of a published structure of the enzyme in complex with a damaged base. To identify critical residues involved in the NIR function, we performed biochemical and structural characterization of Bacillus subtilis AP endonuclease ExoA and compared its crystal structure with the structures of other AP endonucleases: Escherichia coli exonuclease III (Xth), human APE1, and archaeal Mth212. We found conserved amino acid residues in the NIR-specific enzymes APE1, Mth212, and ExoA. Four of these positions were studied by means of point mutations in APE1: we applied substitution with the corresponding residue found in NIR-deficient E. coli Xth (Y128H, N174Q, G231S, and T268D). The APE1-T268D mutant showed a drastically decreased NIR activity and an inverted Mg(2+) dependence of the AP site cleavage activity, which is in line with the presence of an aspartic residue at the equivalent position among other known NIR-deficient AP endonucleases. Taken together, these data show that NIR is an evolutionarily conserved function in the Xth family of AP endonucleases.
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22
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Miroshnikova AD, Kuznetsova AA, Vorobjev YN, Kuznetsov NA, Fedorova OS. Effects of mono- and divalent metal ions on DNA binding and catalysis of human apurinic/apyrimidinic endonuclease 1. MOLECULAR BIOSYSTEMS 2016; 12:1527-39. [PMID: 27063150 DOI: 10.1039/c6mb00128a] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Here, we used stopped-flow fluorescence techniques to conduct a comparative kinetic analysis of the conformational transitions in human apurinic/apyrimidinic endonuclease 1 (APE1) and in DNA containing an abasic site in the course of their interaction. Effects of monovalent (K(+)) and divalent (Mg(2+), Mn(2+), Ca(2+), Zn(2+), Cu(2+), and Ni(2+)) metal ions on DNA binding and catalytic stages were studied. It was shown that the first step of substrate binding (corresponding to formation of a primary enzyme-substrate complex) does not depend on the concentration (0.05-5.0 mM) or the nature of divalent metal ions. In contrast, the initial DNA binding efficiency significantly decreased at a high concentration (5-250 mM) of monovalent K(+) ions, indicating the involvement of electrostatic interactions in this stage. It was also shown that Cu(2+) ions abrogated the DNA binding ability of APE1, possibly, due to a strong interaction with DNA bases and the sugar-phosphate backbone. In the case of Ca(2+) ions, the catalytic activity of APE1 was lost completely with retention of binding potential. Thus, the enzymatic activity of APE1 is increased in the order Zn(2+) < Ni(2+) < Mn(2+) < Mg(2+). Circular dichroism spectra and calculation of the contact area between APE1 and DNA reveal that Mg(2+) ions stabilize the protein structure and the enzyme-substrate complex.
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Affiliation(s)
- Anastasia D Miroshnikova
- Institute of Chemical Biology and Fundamental Medicine (ICBFM), Siberian Branch of Russian Academy of Sciences, 8 Lavrentyev Ave., Novosibirsk 630090, Russia.
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23
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Oppegard LM, Schwanz HA, Towle TR, Kerns RJ, Hiasa H. Fluoroquinolones stimulate the DNA cleavage activity of topoisomerase IV by promoting the binding of Mg(2+) to the second metal binding site. Biochim Biophys Acta Gen Subj 2015; 1860:569-75. [PMID: 26723176 DOI: 10.1016/j.bbagen.2015.12.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/14/2015] [Accepted: 12/22/2015] [Indexed: 01/03/2023]
Abstract
BACKGROUND Fluoroquinolones target bacterial type IIA topoisomerases, DNA gyrase and topoisomerase IV (Topo IV). Fluoroquinolones trap a topoisomerase-DNA covalent complex as a topoisomerase-fluoroquinolone-DNA ternary complex and ternary complex formation is critical for their cytotoxicity. A divalent metal ion is required for type IIA topoisomerase-catalyzed strand breakage and religation reactions. Recent studies have suggested that type IIA topoisomerases use two metal ions, one structural and one catalytic, to carry out the strand breakage reaction. METHODS We conducted a series of DNA cleavage assays to examine the effects of fluoroquinolones and quinazolinediones on Mg(2+)-, Mn(2+)-, or Ca(2+)-supported DNA cleavage activity of Escherichia coli Topo IV. RESULTS In the absence of any drug, 20-30 mM Mg(2+) was required for the maximum levels of the DNA cleavage activity of Topo IV, whereas approximately 1mM of either Mn(2+) or Ca(2+) was sufficient to support the maximum levels of the DNA cleavage activity of Topo IV. Fluoroquinolones promoted the Topo IV-catalyzed strand breakage reaction at low Mg(2+) concentrations where Topo IV alone could not efficiently cleave DNA. CONCLUSIONS AND GENERAL SIGNIFICANCE At low Mg(2+) concentrations, fluoroquinolones may stimulate the Topo IV-catalyzed strand breakage reaction by promoting Mg(2+) binding to metal binding site B through the structural distortion in DNA. As Mg(2+) concentration increases, fluoroquinolones may inhibit the religation reaction by either stabilizing Mg(2+) at site B or inhibition the binding of Mg(2+) to site A. This study provides a molecular basis of how fluoroquinolones stimulate the Topo IV-catalyzed strand breakage reaction by modulating Mg(2+) binding.
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Affiliation(s)
- Lisa M Oppegard
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA.
| | - Heidi A Schwanz
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, USA.
| | - Tyrell R Towle
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, USA.
| | - Robert J Kerns
- Division of Medicinal and Natural Products Chemistry, Department of Pharmaceutical Sciences and Experimental Therapeutics, University of Iowa, 115 S Grand Ave., S321 Pharmacy Building, Iowa City, IA 52242, USA.
| | - Hiroshi Hiasa
- Department of Pharmacology, University of Minnesota Medical School, 6-120 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA.
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24
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Capturing snapshots of APE1 processing DNA damage. Nat Struct Mol Biol 2015; 22:924-31. [PMID: 26458045 PMCID: PMC4654669 DOI: 10.1038/nsmb.3105] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 09/06/2015] [Indexed: 12/22/2022]
Abstract
DNA apurinic-apyrimidinic (AP) sites are prevalent noncoding threats to genomic stability and are processed by AP endonuclease 1 (APE1). APE1 incises the AP-site phosphodiester backbone, generating a DNA-repair intermediate that is potentially cytotoxic. The molecular events of the incision reaction remain elusive, owing in part to limited structural information. We report multiple high-resolution human APE1-DNA structures that divulge new features of the APE1 reaction, including the metal-binding site, the nucleophile and the arginine clamps that mediate product release. We also report APE1-DNA structures with a T-G mismatch 5' to the AP site, representing a clustered lesion occurring in methylated CpG dinucleotides. These structures reveal that APE1 molds the T-G mismatch into a unique Watson-Crick-like geometry that distorts the active site, thus reducing incision. These snapshots provide mechanistic clarity for APE1 while affording a rational framework to manipulate biological responses to DNA damage.
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25
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Schein CH, Ye M, Paul AV, Oberste MS, Chapman N, van der Heden van Noort GJ, Filippov DV, Choi KH. Sequence specificity for uridylylation of the viral peptide linked to the genome (VPg) of enteroviruses. Virology 2015; 484:80-85. [PMID: 26074065 PMCID: PMC4567471 DOI: 10.1016/j.virol.2015.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 05/17/2015] [Accepted: 05/22/2015] [Indexed: 12/16/2022]
Abstract
Enteroviruses (EV) uridylylate a peptide, VPg, as the first step in their replication. VPgpUpU, found free in infected cells, serves as the primer for RNA elongation. The abilities of four polymerases (3D(pol)), from EV-species A-C, to uridylylate VPgs that varied by up to 60% of their residues were compared. Each 3D(pol) was able to uridylylate all five VPgs using polyA RNA as template, while showing specificity for its own genome encoded peptide. All 3D(pol) uridylylated a consensus VPg representing the physical chemical properties of 31 different VPgs. Thus the residues required for uridylylation and the enzymatic mechanism must be similar in diverse EV. As VPg-binding sites differ in co-crystal structures, the reaction is probably done by a second 3D(pol) molecule. The conservation of polymerase residues whose mutation reduces uridylylation but not RNA elongation is compared.
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Affiliation(s)
- Catherine H Schein
- Foundation for Applied Molecular Evolution (FfAME), 13709 Progress Blvd., Alachua, FL 32616, United States.
| | - Mengyi Ye
- Dept. Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, United States
| | - Aniko V Paul
- Dept. Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11790, United States
| | - M Steven Oberste
- Division of Viral Diseases, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, MS G-17, Atlanta, GA 30333, United States
| | - Nora Chapman
- Dept. Pathology and Microbiology, University of Nebraska Medical Center, NE 68198, United States
| | | | - Dmitri V Filippov
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands
| | - Kyung H Choi
- Dept. Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, United States
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26
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Braun W, Schein CH. Membrane interaction and functional plasticity of inositol polyphosphate 5-phosphatases. Structure 2015; 22:664-6. [PMID: 24807076 DOI: 10.1016/j.str.2014.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In this issue of Structure, Trésaugues and colleagues determined the interaction of membrane-bound phosphoinositides with three clinically significant human inositol polyphosphate 5-phosphatases (I5Ps). A comparison to the structures determined with soluble substrates revealed differences in the binding mode and suggested how the I5Ps and apurinic endonuclease (APE1) activities evolved from the same metal-binding active center.
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Affiliation(s)
- Werner Braun
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA; Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Catherine H Schein
- Foundation for Applied Molecular Evolution, 720 SW 2nd Avenue Suite 201, Gainesville, FL 32601, USA
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27
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The role of Asn-212 in the catalytic mechanism of human endonuclease APE1: stopped-flow kinetic study of incision activity on a natural AP site and a tetrahydrofuran analogue. DNA Repair (Amst) 2015; 21:43-54. [PMID: 25038572 DOI: 10.1016/j.dnarep.2014.06.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 11/21/2022]
Abstract
Mammalian AP endonuclease 1 is a pivotal enzyme of the base excision repair pathway acting on apurinic/apyrimidinic sites. Previous structural and biochemical studies showed that the conserved Asn-212 residue is important for the enzymatic activity of APE1. Here, we report a comprehensive pre-steady-state kinetic analysis of two APE1 mutants, each containing amino acid substitutions at position 212, to ascertain the role of Asn-212 in individual steps of the APE1 catalytic mechanism. We applied the stopped-flow technique for detection of conformational transitions in the mutant proteins and DNA substrates during the catalytic cycle, using fluorophores that are sensitive to the micro-environment. Our data indicate that Asn-212 substitution by Asp reduces the rate of the incision step by ∼550-fold, while Ala substitution results in ∼70,000-fold decrease. Analysis of the binding steps revealed that both mutants continued to rapidly and efficiently bind to abasic DNA containing the natural AP site or its tetrahydrofuran analogue (F). Moreover, transient kinetic analysis showed that N212A APE1 possessed a higher binding rate and a higher affinity for specific substrates compared to N212D APE1. Molecular dynamics (MD) simulation revealed a significant dislocation of the key catalytic residues of both mutant proteins relative to wild-type APE1. The analysis of the model structure of N212D APE1 provides evidence for alternate hydrogen bonding between Asn-212 and Asp-210 residues, whereas N212A possesses an extended active site pocket due to Asn removal. Taken together, these biochemical and MD simulation results indicate that Asn-212 is essential for abasic DNA incision, but is not crucial for effective recognition/binding.
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28
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Thakur S, Dhiman M, Tell G, Mantha AK. A review on protein-protein interaction network of APE1/Ref-1 and its associated biological functions. Cell Biochem Funct 2015; 33:101-12. [DOI: 10.1002/cbf.3100] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 02/10/2015] [Accepted: 02/24/2015] [Indexed: 12/17/2022]
Affiliation(s)
- S. Thakur
- Center for Biosciences, School of Basic and Applied Sciences; Central University of Punjab; Bathinda Punjab India
| | - M. Dhiman
- Center for Genetic Diseases and Molecular Medicine, School of Emerging Life Science Technologies; Central University of Punjab; Bathinda Punjab India
| | - G. Tell
- Department of Medical and Biological Sciences; University of Udine; Udine Italy
| | - A. K. Mantha
- Center for Biosciences, School of Basic and Applied Sciences; Central University of Punjab; Bathinda Punjab India
- Department of Biochemistry and Molecular Biology; University of Texas Medical Branch; Galveston TX USA
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29
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Kaur G, Cholia RP, Mantha AK, Kumar R. DNA repair and redox activities and inhibitors of apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1): a comparative analysis and their scope and limitations toward anticancer drug development. J Med Chem 2014; 57:10241-56. [PMID: 25280182 DOI: 10.1021/jm500865u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The apurinic/apyrimidinic endonuclease 1/redox effector factor 1 (APE1/Ref-1) is a multifunctional enzyme involved in DNA repair and activation of transcription factors through its redox function. The evolutionarily conserved C- and N-termini are involved in these functions independently. It is also reported that the activity of APE1/Ref-1 abruptly increases several-fold in various human cancers. The control over the outcomes of these two functions is emerging as a new strategy to combine enhanced DNA damage and chemotherapy in order to tackle the major hurdle of increased cancer cell growth and proliferation. Studies have targeted these two domains individually for the design and development of inhibitors for APE1/Ref-1. Here, we have made, for the first time, an attempt at a comparative analysis of APE1/Ref-1 inhibitors that target both DNA repair and redox activities simultaneously. We further discuss their scope and limitations with respect to the development of potential anticancer agents.
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Affiliation(s)
- Gagandeep Kaur
- Laboratory for Drug Design and Synthesis, Centre for Chemical and Pharmaceutical Sciences, School of Basic and Applied Sciences, Central University of Punjab , Bathinda, 151001, Punjab, India
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30
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He H, Chen Q, Georgiadis MM. High-resolution crystal structures reveal plasticity in the metal binding site of apurinic/apyrimidinic endonuclease I. Biochemistry 2014; 53:6520-9. [PMID: 25251148 PMCID: PMC4204877 DOI: 10.1021/bi500676p] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Apurinic/apyrimidinic
endonuclease I (APE1) is an essential base
excision repair enzyme that catalyzes a Mg2+-dependent
reaction in which the phosphodiester backbone is cleaved 5′
of an abasic site in duplex DNA. This reaction has been proposed to
involve either one or two metal ions bound to the active site. In
the present study, we report crystal structures of Mg2+, Mn2+, and apo-APE1 determined at 1.4, 2.2, and 1.65
Å, respectively, representing two of the highest resolution structures
yet reported for APE1. In our structures, a single well-ordered Mn2+ ion was observed coordinated by D70 and E96; the Mg2+ site exhibited disorder modeled as two closely positioned
sites coordinated by D70 and E96 or E96 alone. Direct metal binding
analysis of wild-type, D70A, and E96A APE1, as assessed by differential
scanning fluorimetry, indicated a role for D70 and E96 in binding
of Mg2+ or Mn2+ to APE1. Consistent with the
disorder exhibited by Mg2+ bound to the active site, two
different conformations of E96 were observed coordinated to Mg2+. A third conformation for E96 in the apo structure is similar
to that observed in the APE1–DNA–Mg2+ complex
structure. Thus, binding of Mg2+ in three different positions
within the active site of APE1 in these crystal structures corresponds
directly with three different conformations of E96. Taken together,
our results are consistent with the initial capture of metal by D70
and E96 and repositioning of Mg2+ facilitated by the structural
plasticity of E96 in the active site.
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Affiliation(s)
- Hongzhen He
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
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31
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Trésaugues L, Silvander C, Flodin S, Welin M, Nyman T, Gräslund S, Hammarström M, Berglund H, Nordlund P. Structural basis for phosphoinositide substrate recognition, catalysis, and membrane interactions in human inositol polyphosphate 5-phosphatases. Structure 2014; 22:744-55. [PMID: 24704254 DOI: 10.1016/j.str.2014.01.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/24/2014] [Accepted: 01/24/2014] [Indexed: 11/15/2022]
Abstract
SHIP2, OCRL, and INPP5B belong to inositol polyphosphate 5-phophatase subfamilies involved in insulin regulation and Lowes syndrome. The structural basis for membrane recognition, substrate specificity, and regulation of inositol polyphosphate 5-phophatases is still poorly understood. We determined the crystal structures of human SHIP2, OCRL, and INPP5B, the latter in complex with phosphoinositide substrate analogs, which revealed a membrane interaction patch likely to assist in sequestering substrates from the lipid bilayer. Residues recognizing the 1-phosphate of the substrates are highly conserved among human family members, suggesting similar substrate binding modes. However, 3- and 4-phosphate recognition varies and determines individual substrate specificity profiles. The high conservation of the environment of the scissile 5-phosphate suggests a common reaction geometry for all members of the human 5-phosphatase family.
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Affiliation(s)
- Lionel Trésaugues
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Camilla Silvander
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden.
| | - Susanne Flodin
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Martin Welin
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Tomas Nyman
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Susanne Gräslund
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Martin Hammarström
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Helena Berglund
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Pär Nordlund
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden; Division of Biophysics, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden; Centre for Biomedical Structural Biology, School of Biological Sciences, Nanyang Technological University, 637551, Singapore.
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32
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Manvilla BA, Pozharski E, Toth EA, Drohat AC. Structure of human apurinic/apyrimidinic endonuclease 1 with the essential Mg2+ cofactor. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2013; 69:2555-62. [PMID: 24311596 PMCID: PMC3852660 DOI: 10.1107/s0907444913027042] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 10/01/2013] [Indexed: 11/10/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) mediates the repair of abasic sites and other DNA lesions and is essential for base-excision repair and strand-break repair pathways. APE1 hydrolyzes the phosphodiester bond at abasic sites, producing 5'-deoxyribose phosphate and the 3'-OH primer needed for repair synthesis. It also has additional repair activities, including the removal of 3'-blocking groups. APE1 is a powerful enzyme that absolutely requires Mg2+, but the stoichiometry and catalytic function of the divalent cation remain unresolved for APE1 and for other enzymes in the DNase I superfamily. Previously reported structures of DNA-free APE1 contained either Sm3+ or Pb2+ in the active site. However, these are poor surrogates for Mg2+ because Sm3+ is not a cofactor and Pb2+ inhibits APE1, and their coordination geometry is expected to differ from that of Mg2+. A crystal structure of human APE1 was solved at 1.92 Å resolution with a single Mg2+ ion in the active site. The structure reveals ideal octahedral coordination of Mg2+ via two carboxylate groups and four water molecules. One residue that coordinates Mg2+ directly and two that bind inner-sphere water molecules are strictly conserved in the DNase I superfamily. This structure, together with a recent structure of the enzyme-product complex, inform on the stoichiometry and the role of Mg2+ in APE1-catalyzed reactions.
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Affiliation(s)
- Brittney A. Manvilla
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
| | - Edwin Pozharski
- Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, USA
| | - Eric A. Toth
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
| | - Alexander C. Drohat
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 108 North Greene Street, Baltimore, MD 21201, USA
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33
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Belousova EA, Vasil'eva IA, Moor NA, Zatsepin TS, Oretskaya TS, Lavrik OI. Clustered DNA lesions containing 5-formyluracil and AP site: repair via the BER system. PLoS One 2013; 8:e68576. [PMID: 23936307 PMCID: PMC3735541 DOI: 10.1371/journal.pone.0068576] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 05/29/2013] [Indexed: 12/31/2022] Open
Abstract
Lesions in the DNA arise under ionizing irradiation conditions or various chemical oxidants as a single damage or as part of a multiply damaged site within 1–2 helical turns (clustered lesion). Here, we explored the repair opportunity of the apurinic/apyrimidinic site (AP site) composed of the clustered lesion with 5-formyluracil (5-foU) by the base excision repair (BER) proteins. We found, that if the AP site is shifted relative to the 5-foU of the opposite strand, it could be repaired primarily via the short-patch BER pathway. In this case, the cleavage efficiency of the AP site-containing DNA strand catalyzed by human apurinic/apyrimidinic endonuclease 1 (hAPE1) decreased under AP site excursion to the 3'-side relative to the lesion in the other DNA strand. DNA synthesis catalyzed by DNA polymerase lambda was more accurate in comparison to the one catalyzed by DNA polymerase beta. If the AP site was located exactly opposite 5-foU it was expected to switch the repair to the long-patch BER pathway. In this situation, human processivity factor hPCNA stimulates the process.
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Affiliation(s)
- Ekaterina A. Belousova
- Laboratory of Bioorganic chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Inna A. Vasil'eva
- Laboratory of Bioorganic chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Nina A. Moor
- Laboratory of Bioorganic chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Timofey S. Zatsepin
- Chemistry Department of Moscow State University and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow, Russia
| | - Tatiana S. Oretskaya
- Chemistry Department of Moscow State University and A.N. Belozersky Institute of Physico-Chemical Biology, Moscow, Russia
| | - Olga I. Lavrik
- Laboratory of Bioorganic chemistry of Enzymes, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
- * E-mail:
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34
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Tsutakawa SE, Shin DS, Mol CD, Izumi T, Arvai AS, Mantha AK, Szczesny B, Ivanov IN, Hosfield DJ, Maiti B, Pique ME, Frankel KA, Hitomi K, Cunningham RP, Mitra S, Tainer JA. Conserved structural chemistry for incision activity in structurally non-homologous apurinic/apyrimidinic endonuclease APE1 and endonuclease IV DNA repair enzymes. J Biol Chem 2013; 288:8445-8455. [PMID: 23355472 DOI: 10.1074/jbc.m112.422774] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Non-coding apurinic/apyrimidinic (AP) sites in DNA form spontaneously and as DNA base excision repair intermediates are the most common toxic and mutagenic in vivo DNA lesion. For repair, AP sites must be processed by 5' AP endonucleases in initial stages of base repair. Human APE1 and bacterial Nfo represent the two conserved 5' AP endonuclease families in the biosphere; they both recognize AP sites and incise the phosphodiester backbone 5' to the lesion, yet they lack similar structures and metal ion requirements. Here, we determined and analyzed crystal structures of a 2.4 Å resolution APE1-DNA product complex with Mg(2+) and a 0.92 Å Nfo with three metal ions. Structural and biochemical comparisons of these two evolutionarily distinct enzymes characterize key APE1 catalytic residues that are potentially functionally similar to Nfo active site components, as further tested and supported by computational analyses. We observe a magnesium-water cluster in the APE1 active site, with only Glu-96 forming the direct protein coordination to the Mg(2+). Despite differences in structure and metal requirements of APE1 and Nfo, comparison of their active site structures surprisingly reveals strong geometric conservation of the catalytic reaction, with APE1 catalytic side chains positioned analogously to Nfo metal positions, suggesting surprising functional equivalence between Nfo metal ions and APE1 residues. The finding that APE1 residues are positioned to substitute for Nfo metal ions is supported by the impact of mutations on activity. Collectively, the results illuminate the activities of residues, metal ions, and active site features for abasic site endonucleases.
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Affiliation(s)
| | - David S Shin
- Scripps Research Institute, La Jolla, California 92037
| | | | - Tadahide Izumi
- University of Kentucky, Lexington, Kentucky 40536; University of Texas Medical Branch, Galveston, Texas 77555
| | | | - Anil K Mantha
- University of Texas Medical Branch, Galveston, Texas 77555
| | | | | | | | | | - Mike E Pique
- Scripps Research Institute, La Jolla, California 92037
| | | | - Kenichi Hitomi
- Lawrence Berkeley National Laboratory, Berkeley, California 94720; Scripps Research Institute, La Jolla, California 92037; Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | | | - Sankar Mitra
- University of Texas Medical Branch, Galveston, Texas 77555
| | - John A Tainer
- Lawrence Berkeley National Laboratory, Berkeley, California 94720; Scripps Research Institute, La Jolla, California 92037.
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35
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Borjigin M, Arenaz P, Stec B. Chinese hamster AP endonuclease operates by a two-metal ion assisted catalytic mechanism. FEBS Lett 2012; 586:242-7. [PMID: 22209979 DOI: 10.1016/j.febslet.2011.12.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 12/18/2011] [Accepted: 12/20/2011] [Indexed: 11/26/2022]
Abstract
The APE1, an important mammalian AP endonuclease, is an essential enzyme in the base excision DNA repair pathway (BER). The number of metal ions involved directly in the catalysis remains controversial. Here we describe the metal ion titration experiments that demonstrate the requirement for two metal ions for the endonuclease activity of the Chinese hamster APE1. The titration with the non-activating metal ion La(3+) showed a biphasic behavior with activating and inhibitory effects of La(3+) in the range of 0-100 μM in the presence of 5 mM Mg(2+). Modeling of the enzyme-substrate/product complexes provided insight into the endonuclease activity and elucidated the nature of the crystal structures. Accordingly, we proposed a reaction scheme for the two-metal ion assisted catalysis of chAPE1 endonuclease activity.
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Affiliation(s)
- Mandula Borjigin
- Department of Chemistry, Bowling Green State University, 144 Overman Hall, Bowling Green, OH 43403, USA.
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36
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Kanazhevskaya LY, Koval VV, Vorobjev YN, Fedorova OS. Conformational dynamics of abasic DNA upon interactions with AP endonuclease 1 revealed by stopped-flow fluorescence analysis. Biochemistry 2012; 51:1306-21. [PMID: 22243137 DOI: 10.1021/bi201444m] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Apurinic/apyrimidinic (AP) sites are abundant DNA lesions arising from exposure to UV light, ionizing radiation, alkylating agents, and oxygen radicals. In human cells, AP endonuclease 1 (APE1) recognizes this mutagenic lesion and initiates its repair via a specific incision of the phosphodiester backbone 5' to the AP site. We have investigated a detailed mechanism of APE1 functioning using fluorescently labeled DNA substrates. A fluorescent adenine analogue, 2-aminopurine, was introduced into DNA substrates adjacent to the abasic site to serve as an on-site reporter of conformational transitions in DNA during the catalytic cycle. Application of a pre-steady-state stopped-flow technique allows us to observe changes in the fluorescence intensity corresponding to different stages of the process in real time. We also detected an intrinsic Trp fluorescence of the enzyme during interactions with 2-aPu-containing substrates. Our data have revealed a conformational flexibility of the abasic DNA being processed by APE1. Quantitative analysis of fluorescent traces has yielded a minimal kinetic scheme and appropriate rate constants consisting of four steps. The results obtained from stopped-flow data have shown a substantial influence of the 2-aPu base location on completion of certain reaction steps. Using detailed molecular dynamics simulations of the DNA substrates, we have attributed structural distortions of AP-DNA to realization of specific binding, effective locking, and incision of the damaged DNA. The findings allowed us to accurately discern the step that corresponds to insertion of specific APE1 amino acid residues into the abasic DNA void in the course of stabilization of the precatalytic complex.
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Affiliation(s)
- Lyubov Yu Kanazhevskaya
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk 630090, Russia
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37
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Oezguen N, Power TD, Urvil P, Feng H, Pothoulakis C, Stamler JS, Braun W, Savidge TC. Clostridial toxins: sensing a target in a hostile gut environment. Gut Microbes 2012; 3:35-41. [PMID: 22356854 PMCID: PMC3337123 DOI: 10.4161/gmic.19250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The current global outbreak of Clostridium difficile infection exemplifies the major public health threat posed by clostridial glucosylating toxins. In the western world, C. difficile infection is one of the most prolific causes of bacterial-induced diarrhea and potentially fatal colitis. Two pathogenic enterotoxins, TcdA and TcdB, cause the disease. Vancomycin and metronidazole remain readily available treatment options for C. difficile infection, but neither is fully effective as is evident by high clinical relapse and fatality rates. Thus, there is an urgent need to find an alternative therapy that preferentially targets the toxins and not the drug-resistant pathogen. Recently, we addressed these critical issues in a Nature Medicine letter, describing a novel host defense mechanism for subverting toxin virulence that we translated into prototypic allosteric therapy for C. difficile infection. In this addendum article, we provide a continued perspective of this antitoxin mechanism and consider the broader implications of therapeutic allostery in combating gut microbial pathogenesis.
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Affiliation(s)
- Numan Oezguen
- Department of Internal Medicine; University of Texas Medical Branch; Galveston, TX USA
| | - Trevor D. Power
- Department of Biochemistry & Molecular Biology; University of Texas Medical Branch; Galveston, TX USA
| | - Petri Urvil
- Department of Internal Medicine; University of Texas Medical Branch; Galveston, TX USA
| | - Hanping Feng
- Department of Microbial Pathogenesis; University of Maryland Dental School; Baltimore, MD USA
| | - Charalabos Pothoulakis
- Inflammatory Bowel Disease; Division of Digestive Diseases; University of California at Los Angeles; Los Angeles, CA USA
| | - Jonathan S. Stamler
- Institute for Transformative Molecular Medicine; Department of Medicine; University Hospitals; Case Western Reserve University; Cleveland, OH USA
| | - Werner Braun
- Department of Biochemistry & Molecular Biology; University of Texas Medical Branch; Galveston, TX USA
| | - Tor C. Savidge
- Department of Internal Medicine; University of Texas Medical Branch; Galveston, TX USA,Correspondence to: Tor C. Savidge;
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38
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Oezguen N, Mantha AK, Izumi T, Schein CH, Mitra S, Braun W. MD simulation and experimental evidence for Mg²+ binding at the B site in human AP endonuclease 1. Bioinformation 2011; 7:184-98. [PMID: 22102776 PMCID: PMC3218521 DOI: 10.6026/97320630007184] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Accepted: 10/03/2011] [Indexed: 11/23/2022] Open
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1), a central enzyme in the base excision repair pathway, cleaves damaged DNA in Mg(2+) dependent reaction. Despite characterization of nine X-ray crystallographic structures of human APE1, in some cases, bound to various metal ions and substrate/product, the position of the metal ion and its stoichiometry for the cleavage reaction are still being debated. While a mutation of the active site E96Q was proposed to eliminate Mg(2+) binding at the "A" site, we show experimentally that this mutant still requires Mg(2+) at concentration similar to that for the wild type enzyme to cleave the AP site in DNA. Molecular dynamics simulations of the wild type APE1, E96Q and a double missense mutant E96Q + D210N indicate that Mg(2+) placed at the A-site destabilizes the bound AP site-containing DNA. In these simulations, the H-bond chain D238-H309-AP site oxygen is broken and the substrate DNA is shifted away from its crystal structure position (1DE9). In contrast, simulations with the Mg(2+) at site B or A+B sites leave the substrate DNA at the position shown in the crystal structure (1DE9). Taken together our MD simulations and biochemical analysis suggests that Mg(2+) binding at the B site is involved in the reaction mechanism associated with endonuclease function of APE1.
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Affiliation(s)
- Numan Oezguen
- Internal Medicine-Endocrinology Department, University of Texas Medical Branch, Galveston, TX 77555-1060, USA
| | - Anil K Mantha
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-1079, USA
| | - Tadahide Izumi
- Stanley S. Scott Cancer Center and Department of Otolaryngology, 533 Bolivar St., University Health Sciences Center, New Orleans, LA 70112, USA
| | - Catherine H Schein
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-1079, USA
| | - Sankar Mitra
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-1079, USA
| | - Werner Braun
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555-1079, USA
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39
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Timofeyeva NA, Koval VV, Ishchenko AA, Saparbaev MK, Fedorova OS. Lys98 substitution in human AP endonuclease 1 affects the kinetic mechanism of enzyme action in base excision and nucleotide incision repair pathways. PLoS One 2011; 6:e24063. [PMID: 21912662 PMCID: PMC3164677 DOI: 10.1371/journal.pone.0024063] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 08/04/2011] [Indexed: 11/18/2022] Open
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) is a key enzyme in the base excision repair (BER) and nucleotide incision repair (NIR) pathways. We recently analyzed the conformational dynamics and kinetic mechanism of wild-type (wt) protein, in a stopped-flow fluorescence study. In this study, we investigated the mutant enzyme APE1K98A using the same approach. Lys98 was known to hydrogen bond to the carboxyl group of Asp70, a residue implicated in binding the divalent metal ion. Our data suggested that the conformational selection and induced fit occur during the enzyme action. We expanded upon the evidence that APE1 can pre-exist in two conformations. The isomerization of an enzyme-product complex in the BER process and the additional isomerization stage of enzyme-substrate complex in the NIR process were established for APE1K98A. These stages had not been registered for the wtAPE1. We found that the K98A substitution resulted in a 12-fold reduction of catalytic constant of 5'-phosphodiester bond hydrolysis in (3-hydroxytetrahydrofuran-2-yl)methyl phosphate (F, tetrahydrofuran) containing substrate, and in 200-fold reduction in 5,6-dihydrouridine (DHU) containing substrate. Thus, the K98A substitution influenced NIR more than BER. We demonstrated that the K98A mutation influenced the formation of primary unspecific enzyme-substrate complex in a complicated manner, depending on the Mg(2+) concentration and pH. This mutation obstructed the induced fit of enzyme in the complex with undamaged DNA and F-containing DNA and appreciably decreased the stability of primary complex upon interaction of enzyme with DNA, containing the natural apurinic/apyrimidinic (AP) site. Furthermore, it significantly delayed the activation of the less active form of enzyme during NIR and slowed down the conformational conversion of the complex of enzyme with the cleavage product of DHU-substrate. Our data revealed that APE1 uses the same active site to catalyze the cleavage of DHU- and AP-substrates.
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Affiliation(s)
- Nadezhda A. Timofeyeva
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Vladimir V. Koval
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
| | - Alexander A. Ishchenko
- CNRS UMR8200 Université Paris-Sud XI, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Murat K. Saparbaev
- CNRS UMR8200 Université Paris-Sud XI, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Olga S. Fedorova
- Siberian Branch of the Russian Academy of Sciences, Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia
- * E-mail:
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40
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Pitts SL, Liou GF, Mitchenall LA, Burgin AB, Maxwell A, Neuman KC, Osheroff N. Use of divalent metal ions in the DNA cleavage reaction of topoisomerase IV. Nucleic Acids Res 2011; 39:4808-17. [PMID: 21300644 PMCID: PMC3113566 DOI: 10.1093/nar/gkr018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
It has long been known that type II topoisomerases require divalent metal ions in order to cleave DNA. Kinetic, mutagenesis and structural studies indicate that the eukaryotic enzymes utilize a novel variant of the canonical two-metal-ion mechanism to promote DNA scission. However, the role of metal ions in the cleavage reaction mediated by bacterial type II enzymes has been controversial. Therefore, to resolve this critical issue, this study characterized the DNA cleavage reaction of Escherichia coli topoisomerase IV. We utilized a series of divalent metal ions with varying thiophilicities in conjunction with oligonucleotides that replaced bridging and non-bridging oxygen atoms at (and near) the scissile bond with sulfur atoms. DNA scission was enhanced when thiophilic metal ions were used with substrates that contained bridging sulfur atoms. In addition, the metal-ion dependence of DNA cleavage was sigmoidal in nature, and rates and levels of DNA cleavage increased when metal ion mixtures were used in reactions. Based on these findings, we propose that topoisomerase IV cleaves DNA using a two-metal-ion mechanism in which one of the metal ions makes a critical interaction with the 3′-bridging atom of the scissile phosphate and facilitates DNA scission by the bacterial type II enzyme.
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Affiliation(s)
- Steven L Pitts
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA
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Kanazhevskaya LY, Koval VV, Zharkov DO, Strauss PR, Fedorova OS. Conformational transitions in human AP endonuclease 1 and its active site mutant during abasic site repair. Biochemistry 2010; 49:6451-61. [PMID: 20575528 DOI: 10.1021/bi100769k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AP endonuclease 1 (APE1) is a crucial enzyme of the base excision repair pathway (BER) in human cells. APE1 recognizes apurinic/apyrimidinic (AP) sites and makes a nick in the phosphodiester backbone 5' to them. The conformational dynamics and presteady-state kinetics of wild-type APE1 and its active site mutant, Y171F-P173L-N174K, have been studied. To observe conformational transitions occurring in the APE1 molecule during the catalytic cycle, we detected intrinsic tryptophan fluorescence of the enzyme under single turnover conditions. DNA duplexes containing a natural AP site, its tetrahydrofuran analogue, or a 2'-deoxyguanosine residue in the same position were used as specific substrates or ligands. The stopped-flow experiments have revealed high flexibility of the APE1 molecule and the complexity of the catalytic process. The fluorescent traces indicate that wild-type APE1 undergoes at least four conformational transitions during the processing of abasic sites in DNA. In contrast, nonspecific interactions of APE1 with undamaged DNA can be described by a two-step kinetic scheme. Rate and equilibrium constants were extracted from the stopped-flow and fluorescence titration data for all substrates, ligands, and products. A replacement of three residues at the enzymatic active site including the replacement of tyrosine 171 with phenylalanine in the enzyme active site resulted in a 2 x 10(4)-fold decrease in the reaction rate and reduced binding affinity. Our data indicate the important role of conformational changes in APE1 for substrate recognition and catalysis.
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Affiliation(s)
- Lyubov Yu Kanazhevskaya
- Institute of Chemical Biology & Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
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Gelin A, Redrejo-Rodríguez M, Laval J, Fedorova OS, Saparbaev M, Ishchenko AA. Genetic and biochemical characterization of human AP endonuclease 1 mutants deficient in nucleotide incision repair activity. PLoS One 2010; 5:e12241. [PMID: 20808930 PMCID: PMC2923195 DOI: 10.1371/journal.pone.0012241] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Accepted: 07/25/2010] [Indexed: 11/19/2022] Open
Abstract
Background Human apurinic/apyrimidinic endonuclease 1 (APE1) is a key DNA repair enzyme involved in both base excision repair (BER) and nucleotide incision repair (NIR) pathways. In the BER pathway, APE1 cleaves DNA at AP sites and 3′-blocking moieties generated by DNA glycosylases. In the NIR pathway, APE1 incises DNA 5′ to a number of oxidatively damaged bases. At present, physiological relevance of the NIR pathway is fairly well established in E. coli, but has yet to be elucidated in human cells. Methodology/Principal Finding We identified amino acid residues in the APE1 protein that affect its function in either the BER or NIR pathway. Biochemical characterization of APE1 carrying single K98A, R185A, D308A and double K98A/R185A amino acid substitutions revealed that all mutants exhibited greatly reduced NIR and 3′→5′ exonuclease activities, but were capable of performing BER functions to some extent. Expression of the APE1 mutants deficient in the NIR and exonuclease activities reduced the sensitivity of AP endonuclease-deficient E. coli xth nfo strain to an alkylating agent, methylmethanesulfonate, suggesting that our APE1 mutants are able to repair AP sites. Finally, the human NIR pathway was fully reconstituted in vitro using the purified APE1, human flap endonuclease 1, DNA polymerase β and DNA ligase I proteins, thus establishing the minimal set of proteins required for a functional NIR pathway in human cells. Conclusion/Significance Taken together, these data further substantiate the role of NIR as a distinct and separable function of APE1 that is essential for processing of potentially lethal oxidative DNA lesions.
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Affiliation(s)
- Aurore Gelin
- CNRS UMR8126, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Modesto Redrejo-Rodríguez
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Jacques Laval
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Olga S. Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
| | - Murat Saparbaev
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
| | - Alexander A. Ishchenko
- CNRS UMR8200 Groupe «Réparation de l′ADN», Université Paris-Sud, Institut de Cancérologie Gustave Roussy, Villejuif, France
- * E-mail:
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43
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Type IIA topoisomerase inhibition by a new class of antibacterial agents. Nature 2010; 466:935-40. [DOI: 10.1038/nature09197] [Citation(s) in RCA: 514] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Accepted: 05/20/2010] [Indexed: 11/08/2022]
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Dupureur CM. One is enough: insights into the two-metal ion nuclease mechanism from global analysis and computational studies. Metallomics 2010; 2:609-20. [PMID: 21072352 DOI: 10.1039/c0mt00013b] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Cynthia M Dupureur
- Department of Chemistry & Biochemistry and The Center for Nanoscience, University of Missouri-St. Louis, One University Blvd., St. Louis, MO 63121, USA.
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45
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Endoribonuclease activity of human apurinic/apyrimidinic endonuclease 1 revealed by a real-time fluorometric assay. Anal Biochem 2009; 398:69-75. [PMID: 19932678 DOI: 10.1016/j.ab.2009.11.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 10/22/2009] [Accepted: 11/16/2009] [Indexed: 11/21/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme with a well-established abasic DNA cleaving activity in the base excision DNA repair pathway and in providing redox activity to several well-known transcription factors. APE1 has recently been shown to cleave at the UA, CA, and UG sites of c-myc RNA in vitro and regulates c-myc messenger RNA (mRNA) in cells. To further understand this new endoribonuclease activity of APE1, we have developed an accurate, sensitive, and rapid real-time endonuclease assay based on a fluorogenic oligodeoxynucleotide substrate with a single ribonucleotide. Using this substrate, we carried out the first kinetic analysis of APE1 endoribonuclease activity. We found that the purified native APE1 cleaves the fluorogenic substrate efficiently, as revealed by a k(cat)/K(m) of 2.62x10(6)M(-1)s(-1), a value that is only 71-fold lower than that obtained with the potent bovine pancreatic RNase A. Ion concentrations ranging from 0.2 to 2mM Mg2+ promoted catalysis, whereas 10 to 20mM Mg2+ was inhibitory to the RNA-cleaving activity of APE1. The monovalent cation K+ was inhibitory except at 20mM, where it significantly stimulated recombinant APE1 activity. These results demonstrate rapid and specific endoribonucleolytic cleavage by APE1 and support the notion that this activity is a previously undefined function of APE1.
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46
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Pingoud V, Wende W, Friedhoff P, Reuter M, Alves J, Jeltsch A, Mones L, Fuxreiter M, Pingoud A. On the divalent metal ion dependence of DNA cleavage by restriction endonucleases of the EcoRI family. J Mol Biol 2009; 393:140-60. [PMID: 19682999 DOI: 10.1016/j.jmb.2009.08.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 08/05/2009] [Accepted: 08/06/2009] [Indexed: 11/18/2022]
Abstract
Restriction endonucleases of the PD...D/EXK family need Mg(2+) for DNA cleavage. Whereas Mg(2+) (or Mn(2+)) promotes catalysis, Ca(2+) (without Mg(2+)) only supports DNA binding. The role of Mg(2+) in DNA cleavage by restriction endonucleases has elicited many hypotheses, differing mainly in the number of Mg(2+) involved in catalysis. To address this problem, we measured the Mg(2+) and Mn(2+) concentration dependence of DNA cleavage by BamHI, BglII, Cfr10I, EcoRI, EcoRII (catalytic domain), MboI, NgoMIV, PspGI, and SsoII, which were reported in co-crystal structure analyses to bind one (BglII and EcoRI) or two (BamHI and NgoMIV) Me(2+) per active site. DNA cleavage experiments were carried out at various Mg(2+) and Mn(2+) concentrations at constant ionic strength. All enzymes show a qualitatively similar Mg(2+) and Mn(2+) concentration dependence. In general, the Mg(2+) concentration optimum (between approximately 1 and 10 mM) is higher than the Mn(2+) concentration optimum (between approximately 0.1 and 1 mM). At still higher Mg(2+) or Mn(2+) concentrations, the activities of all enzymes tested are reduced but can be reactivated by Ca(2+). Based on these results, we propose that one Mg(2+) or Mn(2+) is critical for restriction enzyme activation, and binding of a second Me(2+) plays a role in modulating the activity. Steady-state kinetics carried out with EcoRI and BamHI suggest that binding of a second Mg(2+) or Mn(2+) mainly leads to an increase in K(m), such that the inhibitory effect of excess Mg(2+) or Mn(2+) can be overcome by increasing the substrate concentration. Our conclusions are supported by molecular dynamics simulations and are consistent with the structural observations of both one and two Me(2+) binding to these enzymes.
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Affiliation(s)
- Vera Pingoud
- Institut für Biochemie, Justus-Liebig-Universität, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.
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Sissi C, Palumbo M. Effects of magnesium and related divalent metal ions in topoisomerase structure and function. Nucleic Acids Res 2009; 37:702-11. [PMID: 19188255 PMCID: PMC2647314 DOI: 10.1093/nar/gkp024] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The catalytic steps through which DNA topoisomerases produce their biological effects and the interference of drug molecules with the enzyme–DNA cleavage complex have been thoroughly investigated both from the biophysical and the biochemical point of view. This provides the basic structural insight on how this family of essential enzymes works in living systems and how their functions can be impaired by natural and synthetic compounds. Besides other factors, the physiological environment is known to affect substantially the biological properties of topoisomerases, a key role being played by metal ion cofactors, especially divalent ions (Mg2+), that are crucial to bestow and modulate catalytic activity by exploiting distinctive chemical features such as ionic size, hardness and characteristics of the coordination sphere including coordination number and geometry. Indeed, metal ions mediate fundamental aspects of the topoisomerase-driven transphosphorylation process by affecting the kinetics of the forward and the reverse steps and by modifying the enzyme conformation and flexibility. Of particular interest in type IA and type II enzymes are ionic interactions involving the Toprim fold, a protein domain conserved through evolution that contains a number of acidic residues essential for catalysis. A general two-metal ion mechanism is widely accepted to account for the biophysical and biochemical data thus far available.
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Affiliation(s)
- Claudia Sissi
- Department of Pharmaceutical Sciences, University of Padova, Via Marzolo 5, 35131 Padova, Italy
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48
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Castillo-Acosta VM, Ruiz-Pérez LM, Yang W, González-Pacanowska D, Vidal AE. Identification of a residue critical for the excision of 3'-blocking ends in apurinic/apyrimidinic endonucleases of the Xth family. Nucleic Acids Res 2009; 37:1829-42. [PMID: 19181704 PMCID: PMC2665217 DOI: 10.1093/nar/gkp021] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
DNA single-strand breaks containing 3'-blocking groups are generated from attack of the sugar backbone by reactive oxygen species or after base excision by DNA glycosylase/apurinic/apyrimidinic (AP) lyases. In human cells, APE1 excises sugar fragments that block the 3'-ends thus facilitating DNA repair synthesis. In Leishmania major, the causal agent of leishmaniasis, the APE1 homolog is the class II AP endonuclease LMAP. Expression of LMAP but not of APE1 reverts the hypersensitivity of a xth nfo repair-deficient Escherichia coli strain to the oxidative compound hydrogen peroxide (H(2)O(2)). To identify the residues specifically involved in the repair of oxidative DNA damage, we generated random mutations in the ape1 gene and selected those variants that conferred protection against H(2)O(2). Among the resistant clones, we isolated a mutant in the nuclease domain of APE1 (D70A) with an increased capacity to remove 3'-blocking ends in vitro. D70 of APE1 aligns with A138 of LMAP and mutation of the latter to aspartate significantly reduces its 3'-phosphodiesterase activity. Kinetic analysis shows a novel role of residue D70 in the excision rate of 3'-blocking ends. The functional and structural differences between the parasite and human enzymes probably reflect a divergent molecular evolution of their DNA repair responses to oxidative damage.
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Affiliation(s)
- Víctor M. Castillo-Acosta
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n, 18100 Armilla (Granada), Spain and Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Luis M. Ruiz-Pérez
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n, 18100 Armilla (Granada), Spain and Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Wei Yang
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n, 18100 Armilla (Granada), Spain and Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n, 18100 Armilla (Granada), Spain and Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Antonio E. Vidal
- Instituto de Parasitología y Biomedicina López-Neyra, Consejo Superior de Investigaciones Científicas, Avda. del Conocimiento s/n, 18100 Armilla (Granada), Spain and Laboratory of Molecular Biology, NIDDK, National Institutes of Health, Bethesda, Maryland 20892, USA
- *To whom correspondence should be addressed. Tel: +34 958 181621 (ext. 518); Fax: +34 958 181632;
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Mundle ST, Delaney JC, Essigmann JM, Strauss PR. Enzymatic mechanism of human apurinic/apyrimidinic endonuclease against a THF AP site model substrate. Biochemistry 2009; 48:19-26. [PMID: 19123919 PMCID: PMC2731572 DOI: 10.1021/bi8016137] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The endonucleolytic activity of human apurinic/apyrimidinic endonuclease (AP endo) is a major factor in the maintenance of the integrity of the human genome. There are estimates that this enzyme is responsible for eliminating as many as 10(5) potentially mutagenic and genotoxic lesions from the genome of each cell every day. Furthermore, inhibition of AP endonuclease may be effective in decreasing the dose requirements of chemotherapeutics used in the treatment of cancer as well as other diseases. Therefore, it is essential to accurately and directly characterize the enzymatic mechanism of AP endo. Here we describe specifically designed double-stranded DNA oligomers containing tetrahydrofuran (THF) with a 5'-phosphorothioate linkage as the abasic site substrate. Using H(2)(18)O during the cleavage reaction and leveraging the stereochemical preferences of AP endo and T4 DNA ligase for phosphorothioate substrates, we show that AP endo acts by a one-step associative phosphoryl transfer mechanism on a THF-containing substrate.
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Affiliation(s)
- Sophia T. Mundle
- Department of Biology, Northeastern University, Boston, MA 02115
| | - James C. Delaney
- Departments of Biological Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - John M. Essigmann
- Departments of Biological Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
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50
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Lipton AS, Heck RW, Primak S, McNeill DR, Wilson DM, Ellis PD. Characterization of Mg2+ binding to the DNA repair protein apurinic/apyrimidic endonuclease 1 via solid-state 25Mg NMR spectroscopy. J Am Chem Soc 2008; 130:9332-41. [PMID: 18576638 PMCID: PMC2564828 DOI: 10.1021/ja0776881] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apurinic/apyrimidinic endonuclease 1 (APE1), a member of the divalent cation-dependent phosphoesterase superfamily of proteins that retain the conserved four-layered alpha/beta-sandwich structural core, is an essential protein that functions as part of base excision repair to remove mutagenic and cytotoxic abasic sites from DNA. Using low-temperature solid-state (25)Mg NMR spectroscopy and various mutants of APE1, we demonstrate that Mg(2+) binds to APE1 and a functional APE1-substrate DNA complex with an overall stoichiometry of one Mg(2+) per mole of APE1 as predicted by the X-ray work of Tainer and co-workers (Mol, C. D.; Kuo, C. F.; Thayer, M. M.; Cunningham, R. P.; Tainer, J. A. Nature 1995, 374 , 381-386). However, the NMR spectra show that the single Mg(2+) site is disordered. We discuss the probable reasons for the disorder at the Mg(2+) binding site. The most likely source of this disorder is arrangement of the protein-ligands about the Mg(2+) (cis and trans isomers). The existence of these isomers reinforces the notion of the plasticity of the metal binding site within APE1.
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Affiliation(s)
- A S Lipton
- The Biological Sciences Directorate, Pacific Northwest National Laboratory, K8-98, 902 Battelle Boulevard, Richland, Washington 99352, USA
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