1
|
Kaur R, Nikkel DJ, Aboelnga MM, Wetmore SD. The Impact of DFT Functional, Cluster Model Size, and Implicit Solvation on the Structural Description of Single-Metal-Mediated DNA Phosphodiester Bond Cleavage: The Case Study of APE1. J Phys Chem B 2022; 126:10672-10683. [PMID: 36485014 DOI: 10.1021/acs.jpcb.2c06756] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphodiester bond hydrolysis in nucleic acids is a ubiquitous reaction that can be facilitated by enzymes called nucleases, which often use metal ions to achieve catalytic function. While a two-metal-mediated pathway has been well established for many enzymes, there is growing support that some enzymes require only one metal for the catalytic step. Using human apurinic/apyrimidinic endonuclease (APE1) as a prototypical example and cluster models, this study clarifies the impact of DFT functional, cluster model size, and implicit solvation on single-metal-mediated phosphodiester bond cleavage and provides insight into how to efficiently model this chemistry. Initially, a model containing 69 atoms built from a high-resolution X-ray crystal structure is used to explore the reaction pathway mapped by a range of DFT functionals and basis sets, which provides support for the use of standard functionals (M06-2X and B3LYP-D3) to study this reaction. Subsequently, systematically increasing the model size to 185 atoms by including additional amino acids and altering residue truncation points highlights that small models containing only a few amino acids or β carbon truncation points introduce model strains and lead to incorrect metal coordination. Indeed, a model that contains all key residues (general base and acid, residues that stabilize the substrate, and amino acids that maintain the metal coordination) is required for an accurate structural depiction of the one-metal-mediated phosphodiester bond hydrolysis by APE1, which results in 185 atoms. The additional inclusion of the broader enzyme environment through continuum solvation models has negligible effects. The insights gained in the present work can be used to direct future computational studies of other one-metal-dependent nucleases to provide a greater understanding of how nature achieves this difficult chemistry.
Collapse
Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Dylan J Nikkel
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| | - Mohamed M Aboelnga
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada.,Chemistry Department, Faculty of Science, Damietta University, New Damietta 34517, Egypt
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta T1K 3M4, Canada
| |
Collapse
|
2
|
Kaur R, Aboelnga MM, Nikkel DJ, Wetmore SD. The metal dependence of single-metal mediated phosphodiester bond cleavage: a QM/MM study of a multifaceted human enzyme. Phys Chem Chem Phys 2022; 24:29130-29140. [PMID: 36444615 DOI: 10.1039/d2cp04338f] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleases catalyze the cleavage of phosphodiester bonds in nucleic acids using a range of metal cofactors. Although it is well accepted that many nucleases rely on two metal ions, the one-metal mediated pathway is debated. Furthermore, one-metal mediated nucleases maintain activity in the presence of many different metals, but the underlying reasons for this broad metal specificity are unknown. The human apurinic/apyrimidinic endonuclease (APE1), which plays a key role in DNA repair, transcription regulation, and gene expression, is a prototypical example of a one-metal dependent nuclease. Although Mg2+ is the native metal cofactor, APE1 remains catalytically active in the presence of several metals, with the rate decreasing as Mg2+ > Mn2+ > Ni2+ > Zn2+, while Ca2+ completely abolished the activity. The present work uses quantum mechanics-molecular mechanics techniques to map APE1-facilitated phosphodiester bond hydrolysis in the presence of these metals. The structural differences in stationary points along the reaction pathway shed light on the interplay between several factors that allow APE1 to remain catalytically active for various metals, with the trend in the barrier heights correlating with the experimentally reported APE1 catalytic activity. In contrast, Ca2+ significantly changes the metal coordination and active site geometry, and thus completely inhibits catalysis. Our work thereby provides support for the controversial single-metal mediated phosphodiester bond cleavage and clarifies uncertainties regarding the role of the metal and metal identity in this important reaction. This information is key for future medicinal and biotechnological applications including disease diagnosis and treatment, and protein engineering.
Collapse
Affiliation(s)
- Rajwinder Kaur
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| | - Mohamed M Aboelnga
- Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive West, Lethbridge, Alberta, T1K 3M4, Canada.
| | - Dylan J Nikkel
- 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.
| |
Collapse
|
3
|
Fleming AM, Tran R, Omaga CA, Manage SAH, Burrows CJ, Conboy JC. Second Harmonic Generation Interrogation of the Endonuclease APE1 Binding Interaction with G-Quadruplex DNA. Anal Chem 2022; 94:15027-15032. [PMID: 36269876 PMCID: PMC9945475 DOI: 10.1021/acs.analchem.2c02951] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The binding interaction between the DNA repair enzyme apurinic/apyrimidinic endonuclease-1 (APE1) with promoter G-quadruplex (G4) folds bearing an abasic site (AP) can serve as a gene regulatory switch during oxidative stress. Prior fluorescence-based analysis in solution suggested APE1 binds the VEGF promoter G4 but whether this interaction was specific or not remained an open question. Second harmonic generation (SHG) was used in this work to measure the noncanonical DNA-protein binding interaction in a label-free assay with high sensitivity to demonstrate the interaction is ordered and specific. The binding of APE1 to the VEGF promoter G4 with AP sites modeled by a tetrahydrofuran analogue produced dissociation constants of ∼100 nM that differed from duplex and single-stranded DNA control studies. The SHG measurements confirmed APE1 binds the VEGF G4 folds in a specific manner resolving a remaining question regarding how this endonuclease with gene regulatory features engages G4 folds. The studies demonstrate the power of SHG to interrogate noncanonical DNA-protein interactions providing a foundational example for the use of this analytical method in future biochemical analyses.
Collapse
Affiliation(s)
- Aaron M. Fleming
- 315 S 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT United States, 84112-0850
| | - Renee Tran
- 315 S 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT United States, 84112-0850
| | - Carla A. Omaga
- 315 S 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT United States, 84112-0850
| | - Shereen A. Howpay Manage
- 315 S 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT United States, 84112-0850
| | - Cynthia J. Burrows
- 315 S 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT United States, 84112-0850
| | - John C. Conboy
- 315 S 1400 East, Dept. of Chemistry, University of Utah, Salt Lake City, UT United States, 84112-0850
| |
Collapse
|
4
|
Manage SAH, Fleming AM, Chen HN, Burrows CJ. Cysteine Oxidation to Sulfenic Acid in APE1 Aids G-Quadruplex Binding While Compromising DNA Repair. ACS Chem Biol 2022; 17:2583-2594. [PMID: 36037088 PMCID: PMC9931449 DOI: 10.1021/acschembio.2c00511] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Apurinic/apyrimidinic endonuclease-1 (APE1) is a base excision repair (BER) enzyme that is also engaged in transcriptional regulation. Previous work demonstrated that the enzymatic stalling of APE1 on a promoter G-quadruplex (G4) recruits transcription factors during oxidative stress for gene regulation. Also, during oxidative stress, cysteine (Cys) oxidation is a post-translational modification (PTM) that can change a protein's function. The current study provides a quantitative survey of cysteine oxidation to sulfenic acid in APE1 and how this PTM at specific cysteine residues affects the function of APE1 toward the NEIL3 gene promoter G4 bearing an abasic site. Of the seven cysteine residues in APE1, five (C65, C93, C208, C296, and C310) were prone to carbonate radical anion oxidation to yield sulfenic acids that were identified and quantified by mass spectrometry. Accordingly, five Cys-to-serine (Ser) mutants of APE1 were prepared and found to have attenuated levels of endonuclease activity, depending on the position, while KD values generally decreased for G4 binding, indicating greater affinity. These data support the concept that cysteine oxidation to sulfenic acid can result in modified APE1 that enhances G4 binding at the expense of endonuclease activity during oxidative stress. Cysteine oxidation to sulfenic acid residues should be considered as one of the factors that may trigger a switch from base excision repair activity to transcriptional modulation by APE1.
Collapse
Affiliation(s)
- Shereen A. Howpay Manage
- Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, UT 84112-0850, United States
| | - Aaron M. Fleming
- Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, UT 84112-0850, United States
| | - Hsiao-Nung Chen
- Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, UT 84112-0850, United States
| | - Cynthia J. Burrows
- Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, UT 84112-0850, United States
| |
Collapse
|
5
|
Bakman AS, Ishchenko AA, Saparbaev M, Fedorova OS, Kuznetsov NA. Pre-steady-state kinetic and mutational insights into mechanisms of endo- and exonuclease DNA processing by mutant forms of human AP endonuclease. Biochim Biophys Acta Gen Subj 2022; 1866:130198. [PMID: 35809816 DOI: 10.1016/j.bbagen.2022.130198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/09/2022] [Accepted: 06/27/2022] [Indexed: 11/19/2022]
Abstract
Human apurinic/apyrimidinic endonuclease APE1 catalyzes endonucleolytic hydrolysis of phosphodiester bonds on the 5' side of structurally unrelated damaged nucleotides in DNA or native nucleotides in RNA. APE1 additionally possesses 3'-5'-exonuclease, 3'-phosphodiesterase, and 3'-phosphatase activities. According to structural data, endo- and exonucleolytic cleavage of DNA is executed in different complexes when the excised residue is everted from the duplex or placed within the intrahelical DNA cavity without nucleotide flipping. In this study, we investigated the functions of residues Arg177, Arg181, Tyr171 and His309 in the APE1 endo- and exonucleolytic reactions. The interaction between residues Arg177 and Met270, which was hypothesized recently to be a switch for endo- and exonucleolytic catalytic mode regulation, was verified by pre-steady-state kinetic analysis of the R177A APE1 mutant. The function of another DNA-binding-site residue, Arg181, was analyzed too; it changed its conformation when enzyme-substrate and enzyme-product complexes were compared. Mutation R181A significantly facilitated the product dissociation stage and only weakly affected DNA-binding affinity. Moreover, R181A reduced the catalytic rate constant severalfold due to a loss of contact with a phosphate group. Finally, the protonation/deprotonation state of residues Tyr171 and His309 in the catalytic reaction was verified by their substitution. Mutations Y171F and H309A inhibited the chemical step of the AP endonucleolytic reaction by several orders of magnitude with retention of capacity for (2R,3S)-2-(hydroxymethyl)-3-hydroxytetrahydrofuran-containing-DNA binding and without changes in the pH dependence profile of AP endonuclease activity, indicating that deprotonation of these residues is likely not important for the catalytic reaction.
Collapse
Affiliation(s)
- Artemiy S Bakman
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Alexander A Ishchenko
- Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Murat Saparbaev
- Group «Mechanisms of DNA Repair and Carcinogenesis», CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia; Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia.
| |
Collapse
|
6
|
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.
Collapse
|
7
|
Ahlawat S, Mote KR, Lakomek NA, Agarwal V. Solid-State NMR: Methods for Biological Solids. Chem Rev 2022; 122:9643-9737. [PMID: 35238547 DOI: 10.1021/acs.chemrev.1c00852] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In the last two decades, solid-state nuclear magnetic resonance (ssNMR) spectroscopy has transformed from a spectroscopic technique investigating small molecules and industrial polymers to a potent tool decrypting structure and underlying dynamics of complex biological systems, such as membrane proteins, fibrils, and assemblies, in near-physiological environments and temperatures. This transformation can be ascribed to improvements in hardware design, sample preparation, pulsed methods, isotope labeling strategies, resolution, and sensitivity. The fundamental engagement between nuclear spins and radio-frequency pulses in the presence of a strong static magnetic field is identical between solution and ssNMR, but the experimental procedures vastly differ because of the absence of molecular tumbling in solids. This review discusses routinely employed state-of-the-art static and MAS pulsed NMR methods relevant for biological samples with rotational correlation times exceeding 100's of nanoseconds. Recent developments in signal filtering approaches, proton methodologies, and multiple acquisition techniques to boost sensitivity and speed up data acquisition at fast MAS are also discussed. Several examples of protein structures (globular, membrane, fibrils, and assemblies) solved with ssNMR spectroscopy have been considered. We also discuss integrated approaches to structurally characterize challenging biological systems and some newly emanating subdisciplines in ssNMR spectroscopy.
Collapse
Affiliation(s)
- Sahil Ahlawat
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Kaustubh R Mote
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| | - Nils-Alexander Lakomek
- University of Düsseldorf, Institute for Physical Biology, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Vipin Agarwal
- Tata Institute of Fundamental Research Hyderabad, Survey No. 36/P Gopanpally, Serilingampally, Ranga Reddy District, Hyderabad 500046, Telangana, India
| |
Collapse
|
8
|
Wu Z, Duan H, Cheng Y, Guo D, Peng L, Hu Y, Hu J, Luo T. A novel ligand swing-mediated active site coordination change of human apurinic/apyrimidinic endonuclease 1: A potential cytotoxic mechanism of nickel ion in the base excision repair. Chem Phys 2022. [DOI: 10.1016/j.chemphys.2022.111456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
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.
Collapse
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
| |
Collapse
|
11
|
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.
Collapse
|
12
|
He Y, Wang Y, Qin C, Xu Y, Cheng K, Xu H, Tian B, Zhao Y, Wang L, Hua Y. Structural and Functional Characterization of a Unique AP Endonuclease From Deinococcus radiodurans. Front Microbiol 2020; 11:1178. [PMID: 33117296 PMCID: PMC7548837 DOI: 10.3389/fmicb.2020.01178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/08/2020] [Indexed: 11/13/2022] Open
Abstract
Various endogenous and exogenous agents cause DNA damage, including apurinic/apyrimidinic (AP) sites. Due to their cytotoxic effects, AP sites are usually cleaved by AP endonuclease through the base excision repair (BER) pathway. Deinococcus radiodurans, an extraordinary radiation-resistant bacterium, is known as an ideal model organism for elucidating DNA repair processes. Here, we have investigated a unique AP endonuclease (DrXth) from D. radiodurans and found that it possesses AP endonuclease, 3'-phosphodiesterase, 3'-phosphatase, and 3'-5' exonuclease but has no nucleotide incision repair (NIR) activity. We also found that Mg2+ and Mn2+ were the preferred divalent metals for endonuclease and exonuclease activities, respectively. In addition, DrXth were crystallized and the crystals diffracted to 1.5 Å. Structural and biochemical analyses demonstrated that residue Gly198 is the key residue involved in the substrate DNA binding and cleavage. Deletion of the drxth gene in D. radiodurans caused elevated sensitivity to DNA damage agents and increased spontaneous mutation frequency. Overall, our results indicate that DrXth is an important AP endonuclease involved in BER pathway and functions in conjunction with other DNA repair enzymes to maintain the genome stability.
Collapse
Affiliation(s)
- Yuan He
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Yiyi Wang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Chen Qin
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Ying Xu
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Kaiying Cheng
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Hong Xu
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Bing Tian
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Ye Zhao
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Liangyan Wang
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| | - Yuejin Hua
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Institute of Biophysics, Zhejiang University, Hangzhou, China
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
Zhou M, Feng C, Mao D, Yang S, Ren L, Chen G, Zhu X. An electrochemical biosensor integrating immunoassay and enzyme activity analysis for accurate detection of active human apurinic/apyrimidinic endonuclease 1. Biosens Bioelectron 2019; 142:111558. [DOI: 10.1016/j.bios.2019.111558] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/21/2019] [Accepted: 07/31/2019] [Indexed: 12/15/2022]
|
15
|
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
| |
Collapse
|
16
|
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.
Collapse
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.
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Whitaker AM, Flynn TS, Freudenthal BD. Molecular snapshots of APE1 proofreading mismatches and removing DNA damage. Nat Commun 2018; 9:399. [PMID: 29374164 PMCID: PMC5785985 DOI: 10.1038/s41467-017-02175-y] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/10/2017] [Indexed: 01/13/2023] Open
Abstract
Human apurinic/apyrimidinic (AP) endonuclease 1 (APE1) is an essential DNA repair enzyme which uses a single active site to process DNA damage via two distinct activities: (1) AP-endonuclease and (2) 3′ to 5′ exonuclease. The AP-endonuclease activity cleaves at AP-sites, while the exonuclease activity excises bulkier 3′ mismatches and DNA damage to generate clean DNA ends suitable for downstream repair. Molecular details of the exonuclease reaction and how one active site can accommodate various toxic DNA repair intermediates remains elusive despite being biologically important. Here, we report multiple high-resolution APE1–DNA structural snapshots revealing how APE1 removes 3′ mismatches and DNA damage by placing the 3′ group within the intra-helical DNA cavity via a non-base flipping mechanism. This process is facilitated by a DNA nick, instability of a mismatched/damaged base, and bending of the DNA. These results illustrate how APE1 cleanses DNA dirty-ends to generate suitable substrates for downstream repair enzymes. The essential DNA repair enzyme apurinic/apyrimidinic endonuclease 1 (APE1) has both endonuclease and exonuclease activities. Here, the authors present DNA bound human APE1 crystal structures which give insights into its exonuclease mechanism.
Collapse
Affiliation(s)
- Amy M Whitaker
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Tony S Flynn
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Bret D Freudenthal
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
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.
Collapse
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.
| | | | | | | | | |
Collapse
|
21
|
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.
Collapse
|
22
|
Xu J, Lucier BEG, Sinelnikov R, Terskikh VV, Staroverov VN, Huang Y. Monitoring and Understanding the Paraelectric-Ferroelectric Phase Transition in the Metal-Organic Framework [NH4][M(HCOO)3] by Solid-State NMR Spectroscopy. Chemistry 2015; 21:14348-61. [DOI: 10.1002/chem.201501954] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 11/08/2022]
|
23
|
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.
Collapse
Affiliation(s)
- Hongzhen He
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana 46202, United States
| | | | | |
Collapse
|
24
|
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.
Collapse
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.
| |
Collapse
|
25
|
Abstract
SIGNIFICANCE Human apurinic/apyrimidinic endonuclease 1 (APE1, also known as REF-1) was isolated based on its ability to cleave at AP sites in DNA or activate the DNA binding activity of certain transcription factors. We review herein topics related to this multi-functional DNA repair and stress-response protein. RECENT ADVANCES APE1 displays homology to Escherichia coli exonuclease III and is a member of the divalent metal-dependent α/β fold-containing phosphoesterase superfamily of enzymes. APE1 has acquired distinct active site and loop elements that dictate substrate selectivity, and a unique N-terminus which at minimum imparts nuclear targeting and interaction specificity. Additional activities ascribed to APE1 include 3'-5' exonuclease, 3'-repair diesterase, nucleotide incision repair, damaged or site-specific RNA cleavage, and multiple transcription regulatory roles. CRITICAL ISSUES APE1 is essential for mouse embryogenesis and contributes to cell viability in a genetic background-dependent manner. Haploinsufficient APE1(+/-) mice exhibit reduced survival, increased cancer formation, and cellular/tissue hyper-sensitivity to oxidative stress, supporting the notion that impaired APE1 function associates with disease susceptibility. Although abnormal APE1 expression/localization has been seen in cancer and neuropathologies, and impaired-function variants have been described, a causal link between an APE1 defect and human disease remains elusive. FUTURE DIRECTIONS Ongoing efforts aim at delineating the biological role(s) of the different APE1 activities, as well as the regulatory mechanisms for its intra-cellular distribution and participation in diverse molecular pathways. The determination of whether APE1 defects contribute to human disease, particularly pathologies that involve oxidative stress, and whether APE1 small-molecule regulators have clinical utility, is central to future investigations.
Collapse
Affiliation(s)
- Mengxia Li
- Intramural Research Program, Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
| | | |
Collapse
|
26
|
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.
Collapse
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
| |
Collapse
|
27
|
Burgess KMN, Xu Y, Leclerc MC, Bryce DL. Insight into Magnesium Coordination Environments in Benzoate and Salicylate Complexes through 25Mg Solid-State NMR Spectroscopy. J Phys Chem A 2013; 117:6561-70. [DOI: 10.1021/jp405145b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Kevin M. N. Burgess
- Department of Chemistry
and Centre for Catalysis Research and
Innovation, University of Ottawa, 10 Marie
Curie Private, Ottawa, Ontario, Canada K1N 6N5
| | - Yang Xu
- Department of Chemistry
and Centre for Catalysis Research and
Innovation, University of Ottawa, 10 Marie
Curie Private, Ottawa, Ontario, Canada K1N 6N5
| | - Matthew C. Leclerc
- Department of Chemistry
and Centre for Catalysis Research and
Innovation, University of Ottawa, 10 Marie
Curie Private, Ottawa, Ontario, Canada K1N 6N5
| | - David L. Bryce
- Department of Chemistry
and Centre for Catalysis Research and
Innovation, University of Ottawa, 10 Marie
Curie Private, Ottawa, Ontario, Canada K1N 6N5
| |
Collapse
|
28
|
Perras FA, Viger-Gravel J, Burgess KMN, Bryce DL. Signal enhancement in solid-state NMR of quadrupolar nuclei. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2013; 51-52:1-15. [PMID: 23336997 DOI: 10.1016/j.ssnmr.2012.11.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 11/13/2012] [Accepted: 11/18/2012] [Indexed: 06/01/2023]
Abstract
Recent progress in the development and application of signal enhancement methods for NMR of quadrupolar nuclei in solids is presented. First, various pulse schemes for manipulating the populations of the satellite transitions in order to increase the signal of the central transition (CT) in stationary and rotating solids are evaluated (e.g., double-frequency sweeps, hyperbolic secant pulses). Second, the utility of the quadrupolar Carr-Purcell-Meiboom-Gill (QCPMG) and WURST-QCPMG pulse sequences for the rapid and efficient acquisition of particularly broad CT powder patterns is discussed. Third, less frequently used experiments involving polarization transfer from abundant nuclear spins (cross-polarization) or from unpaired electrons (dynamic nuclear polarization) are assessed in the context of recent examples. Advantages and disadvantages of particular enhancement schemes are highlighted and an outlook on possible future directions for the signal enhancement of quadrupolar nuclei in solids is offered.
Collapse
Affiliation(s)
- Frédéric A Perras
- Department of Chemistry, University of Ottawa, Ottawa, Ontario, Canada
| | | | | | | |
Collapse
|
29
|
Xu J, Terskikh VV, Huang Y. Resolving multiple non-equivalent metal sites in magnesium-containing metal-organic frameworks by natural abundance (25)Mg solid-state NMR spectroscopy. Chemistry 2013; 19:4432-6. [PMID: 23450828 DOI: 10.1002/chem.201300113] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Indexed: 11/06/2022]
Abstract
In a spin: Directly differentiating multiple Mg sites in Mg-containing MOFs by (25)Mg solid-state NMR spectroscopy is very challenging at natural abundance. By performing (25)Mg two-dimensional triple-quantum magic-angle spinning solid-state NMR experiments at a magnetic field of 21.1 T at natural abundance, four non-equivalent Mg sites with very similar local environments in α-Mg(3)(HCOO)(6) were unambiguously resolved (see figure).
Collapse
Affiliation(s)
- Jun Xu
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
| | | | | |
Collapse
|
30
|
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.
Collapse
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.
| |
Collapse
|
31
|
Xu J, Terskikh VV, Huang Y. (25)Mg Solid-State NMR: A Sensitive Probe of Adsorbing Guest Molecules on a Metal Center in Metal-Organic Framework CPO-27-Mg. J Phys Chem Lett 2013; 4:7-11. [PMID: 26291203 DOI: 10.1021/jz301954t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Metal-organic frameworks (MOFs) have excellent adsorption capability. To understand their adsorptive properties requires detailed information on the host-guest interaction. The information on MOF desolvation (or activation) is also crucial because the very first step of many applications requires removal of the solvent molecules occluded inside of the pores. Unfortunately, such information is not always available from powder XRD data. Solid-state NMR is an excellent complementary technique to XRD. CPO-27-Mg is a MOF with unusual adsorption ability. The adsorption involves a direct interaction between Mg and guest species. Herein, we present, for the first time, a natural abundance (25)Mg solid-state NMR study of CPO-27-Mg at an ultrahigh magnetic field of 21.1 T. The results provide new physical insights into the effects of dehydration/rehydration and adsorption of guest species on the Mg local environment.
Collapse
Affiliation(s)
- Jun Xu
- †Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| | - Victor V Terskikh
- ‡Measurement Science and Standards, National Research Council Canada, Ottawa, Ontario, Canada K1A 0R6
| | - Yining Huang
- †Department of Chemistry, The University of Western Ontario, London, Ontario, Canada N6A 5B7
| |
Collapse
|
32
|
Khaliullin I, Nilov D, Shapovalova I, Švedas V. Construction of a Full-Atomic Mechanistic Model of Human Apurinic/Apyrimidinic Endonuclease APE1 for Virtual Screening of Novel Inhibitors. Acta Naturae 2012; 4:80-6. [PMID: 22872814 PMCID: PMC3408706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
A full-atomic molecular model of human apurinic/apyrimidinic endonuclease APE1, an important enzyme in the DNA repair system, has been constructed. The research consisted of hybrid quantum mechanics/molecular mechanics modeling of the enzyme-substrate interactions, as well as calculations of the ionization states of the amino acid residues of the active site of the enzyme. The choice of the APE1 mechanism with an Asp210 residue as a proton acceptor was validated by means of a generalization of modeling and experimental data. Interactions were revealed in the active site that are of greatest significance for binding the substrate and potential APE1 inhibitors (potential co-drugs of interest in the chemo- and radiotherapy of oncological diseases).
Collapse
Affiliation(s)
- I.G. Khaliullin
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State
University
| | - D.K. Nilov
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State
University
- Lomonosov Moscow State University, Faculty of Bioengineering and
Bioinformatics
| | - I.V. Shapovalova
- Lomonosov Moscow State University, Faculty of Bioengineering and
Bioinformatics
| | - V.K. Švedas
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State
University
- Lomonosov Moscow State University, Faculty of Bioengineering and
Bioinformatics
| |
Collapse
|
33
|
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.
Collapse
Affiliation(s)
- Mandula Borjigin
- Department of Chemistry, Bowling Green State University, 144 Overman Hall, Bowling Green, OH 43403, USA.
| | | | | |
Collapse
|
34
|
Rossini AJ, Zagdoun A, Lelli M, Gajan D, Rascón F, Rosay M, Maas WE, Copéret C, Lesage A, Emsley L. One hundred fold overall sensitivity enhancements for Silicon-29 NMR spectroscopy of surfaces by dynamic nuclear polarization with CPMG acquisition. Chem Sci 2012. [DOI: 10.1039/c1sc00550b] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
35
|
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.
Collapse
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
| |
Collapse
|
36
|
Variation in the internalization of differently sized nanoparticles induces different DNA-damaging effects on a macrophage cell line. Arch Toxicol 2011; 85:1575-88. [DOI: 10.1007/s00204-011-0725-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Accepted: 06/08/2011] [Indexed: 11/25/2022]
|
37
|
Griffin JM, Berry AJ, Ashbrook SE. Observation of "hidden" magnesium: first-principles calculations and 25Mg solid-state NMR of enstatite. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2011; 40:91-99. [PMID: 21871785 DOI: 10.1016/j.ssnmr.2011.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 08/02/2011] [Accepted: 08/03/2011] [Indexed: 05/31/2023]
Abstract
(25)Mg NMR parameters have been determined for two polymorphs of enstatite (MgSiO(3)), an important magnesium silicate phase present as a major component of the Earth's upper mantle. The crystal structures of both polymorphs contain two crystallographically distinct magnesium sites; however, only a single resonance is observed in (25)Mg MAS NMR spectra recorded at 14.1 and 20.0 T. First-principles calculations performed on geometry-optimised crystal structures reveal that the quadrupolar interaction for the second site is expected to be very large, resulting in extensive broadening of the spectral resonance, explaining its apparent absence in the NMR spectrum. (25)Mg QCPMG NMR experiments employing variable offset cumulative spectroscopy (VOCS) are used to observe the broadened site and enable measurement of NMR parameters. The large difference in quadrupolar interaction between the two crystallographic magnesium sites is rationalised qualitatively in terms of the distortion of the local coordination environment as well as longer-range effects using a simple point charge model.
Collapse
Affiliation(s)
- John M Griffin
- School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews, UK
| | | | | |
Collapse
|
38
|
Zhu J, Huang Y. A natural abundance solid-state 25Mg NMR study of layered magnesium phosphates. CAN J CHEM 2011. [DOI: 10.1139/v10-171] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Natural abundance 25Mg solid-state magic-angle spinning and static NMR spectra of several representative layered magnesium phosphates were acquired at 21.1 and 9.4 T by using quadrupolar echo and double-frequency sweep quadrupolar Carr–Purcell–Meiboom–Gill pulse sequences. The spectra were dominated by the second-order quadrupolar interaction. The electric field gradient tensor parameters were extracted from the spectra via spectral simulations. These parameters, such as the quadrupolar coupling constant (CQ), appear to be sensitive to some parameters describing the distortion of the MgO6 octahedron in the layer. The empirical relationships between CQ and several structural parameters were established and used to obtain partial information on the Mg environment in a layered material (MgHPO4·1.2H2O) with unknown structure. Theoretical calculations suggest that the CQ values of the Mg sites are affected not only by the oxygen atoms in the first coordination sphere, but also by the spatial arrangements of the atoms in the second and third coordination spheres and beyond.
Collapse
Affiliation(s)
- Jianfeng Zhu
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
| | - Yining Huang
- Department of Chemistry, The University of Western Ontario, London, ON N6A 5B7, Canada
| |
Collapse
|
39
|
MacGregor AW, O'Dell LA, Schurko RW. New methods for the acquisition of ultra-wideline solid-state NMR spectra of spin-1/2 nuclides. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2011; 208:103-113. [PMID: 21130011 DOI: 10.1016/j.jmr.2010.10.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 10/15/2010] [Accepted: 10/16/2010] [Indexed: 05/30/2023]
Abstract
The Wideband Uniform Rate Smooth Truncation - Carr-Purcell Meiboom-Gill (WURST-CPMG) pulse sequence was recently introduced as a new method of acquiring ultra-wideline solid-state NMR (SSNMR) patterns of quadrupolar nuclei (Chem. Phys. Lett. 464 (2008) 97). Herein, we describe the application of the WURST-CPMG pulse sequence to stationary samples (i.e., non-spinning or "static" samples) of various spin-1/2 nuclides ((119)Sn, (207)Pb, (199)Hg and (195)Pt) in order to examine its effectiveness for acquiring ultra-wideline SSNMR patterns. WURST-CPMG is compared to the CPMG and Cross Polarization (CP)-CPMG pulse sequences in select cases ((119)Sn and (207)Pb, respectively), and its usefulness in obtaining ultra-wideline SSNMR spectra in a piecewise fashion is explored. In addition, a preliminary investigation of pulses generated using optimal control theory (OCT) for the purpose of wideline excitation is presented; spectra acquired using these pulses are compared with standard, rectangular pulses of similar pulse powers. Both methods show much promise for acquiring high quality wideline patterns dominated by chemical shift anisotropy, with minimal distortions and significantly reduced experimental times.
Collapse
Affiliation(s)
- Alan W MacGregor
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4
| | | | | |
Collapse
|
40
|
|
41
|
Rossini AJ, Hung I, Johnson SA, Slebodnick C, Mensch M, Deck PA, Schurko RW. Solid-State 91Zr NMR Spectroscopy Studies of Zirconocene Olefin Polymerization Catalyst Precursors. J Am Chem Soc 2010; 132:18301-17. [DOI: 10.1021/ja107749b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Aaron J. Rossini
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| | - Ivan Hung
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| | - Samuel A. Johnson
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| | - Carla Slebodnick
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| | - Mike Mensch
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| | - Paul A. Deck
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| | - Robert W. Schurko
- Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4, and Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0121, United States
| |
Collapse
|
42
|
Wilson DM, Simeonov A. Small molecule inhibitors of DNA repair nuclease activities of APE1. Cell Mol Life Sci 2010; 67:3621-31. [PMID: 20809131 PMCID: PMC2956791 DOI: 10.1007/s00018-010-0488-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 10/19/2022]
Abstract
APE1 is a multifunctional protein that possesses several nuclease activities, including the ability to incise at apurinic/apyrimidinic (AP) sites in DNA or RNA, to excise 3'-blocking termini from DNA ends, and to cleave at certain oxidized base lesions in DNA. Pre-clinical and clinical data indicate a role for APE1 in the pathogenesis of cancer and in resistance to DNA-interactive drugs, particularly monofunctional alkylators and antimetabolites. In an effort to improve the efficacy of therapeutic compounds, such as temozolomide, groups have begun to develop high-throughput screening assays and to identify small molecule inhibitors against APE1 repair nuclease activities. It is envisioned that such inhibitors will be used in combinatorial treatment paradigms to enhance the efficacy of DNA-interactive drugs that introduce relevant cytotoxic DNA lesions. In this review, we summarize the current state of the efforts to design potent and selective inhibitors against APE1 AP site incision activity.
Collapse
Affiliation(s)
- David M Wilson
- Laboratory of Molecular Gerontology, Biomedical Research Center, National Institute on Aging, NIH, IRP, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | | |
Collapse
|
43
|
Affiliation(s)
- Shi Bai
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA
| | | | | |
Collapse
|
44
|
Hung I, Gan Z. On the practical aspects of recording wideline QCPMG NMR spectra. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 204:256-265. [PMID: 20359918 DOI: 10.1016/j.jmr.2010.03.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 03/02/2010] [Accepted: 03/02/2010] [Indexed: 05/29/2023]
Abstract
The practical aspects of applying CPMG for acquisition of wideline powder patterns are examined. It is shown that most distortions/modulations of spikelet spectra can be traced to the incoherent signal averaging from multiple coherence transfer pathways. A strategy for minimizing these distortions/modulations is described. Also, a few interesting observations regarding the implementation of the wideline WURST-QCPMG experiment are presented, namely the accumulation of second-order signal phase and the effects of varying the sweep rate and rf field of chirp pulses.
Collapse
Affiliation(s)
- Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | | |
Collapse
|
45
|
Hung I, Shetty K, Ellis PD, Brey WW, Gan Z. High-field QCPMG NMR of large quadrupolar patterns using resistive magnets. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2009; 36:159-63. [PMID: 19913391 DOI: 10.1016/j.ssnmr.2009.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Revised: 10/09/2009] [Accepted: 10/21/2009] [Indexed: 05/06/2023]
Abstract
Spectroscopy in a high magnetic field reduces second-order quadrupolar shift while increasing chemical shift. It changes the scale between quadrupolar and chemical shift of half-integer quadrupolar spins. The application of QCPMG multiple echo for acquiring large quadrupolar pattern under the high magnetic field of a 25 T resistive magnet is presented for acquiring large quadrupolar patterns. It shows that temporal field fluctuations and spatial homogeneity of the Keck magnet at the NHMFL contribute about +/- 20 ppm in line broadening. NMR patterns which have breadths of hundreds to thousands of kilohertz can be efficiently recorded using a combination of QCPMG and magnetic field stepping with negligible hindrance from the inhomogeneity and field fluctuations of powered magnets.
Collapse
Affiliation(s)
- Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | | | | | | | | |
Collapse
|
46
|
Cahill L, Hanna J, Wong A, Freitas JC, Yates J, Harris R, Smith M. Natural Abundance25Mg Solid-State NMR of Mg Oxyanion Systems: A Combined Experimental and Computational Study. Chemistry 2009; 15:9785-98. [DOI: 10.1002/chem.200900346] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
47
|
Laurencin D, Gervais C, Wong A, Coelho C, Mauri F, Massiot D, Smith ME, Bonhomme C. Implementation of High Resolution 43Ca Solid State NMR Spectroscopy: Toward the Elucidation of Calcium Sites in Biological Materials. J Am Chem Soc 2009; 131:13430-40. [DOI: 10.1021/ja904553q] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Danielle Laurencin
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Christel Gervais
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Alan Wong
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Cristina Coelho
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Francesco Mauri
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Dominique Massiot
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Mark E. Smith
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| | - Christian Bonhomme
- Department of Physics, University of Warwick, Coventry, CV4 7AL, UK, UPMC Univ Paris 06, UMR CNRS 7574, Laboratoire de Chimie de la Matière Condensée de Paris, F-75005 Paris, France, UPMC Univ Paris 06, UMR 7590, Institut de Minéralogie et de Physique des Milieux Condensés, F-75005 Paris, France, and CEMHTI, CNRS UPR 3079, Université d’Orléans, 1D avenue de la Recherche Scientifique, Orléans, France
| |
Collapse
|
48
|
Widdifield CM, Bryce DL. Crystallographic structure refinement with quadrupolar nuclei: a combined solid-state NMR and GIPAW DFT example using MgBr2. Phys Chem Chem Phys 2009; 11:7120-2. [DOI: 10.1039/b911448n] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
49
|
Application of static microcoils and WURST pulses for solid-state ultra-wideline NMR spectroscopy of quadrupolar nuclei. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.10.044] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|