1
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Li K, Yatsunyk LA, Neidle S. Machine learning shows torsion angle preferences in left-handed and right-handed quadruplex DNAs. Biophys J 2022; 121:4874-4881. [PMID: 35999813 PMCID: PMC9808593 DOI: 10.1016/j.bpj.2022.08.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 07/21/2022] [Accepted: 08/18/2022] [Indexed: 01/07/2023] Open
Abstract
Left-handed G quadruplexes (LHG4) have been recently discovered as a new class of G quadruplexes. The biological functions of LHG4s are still unknown, but they share a striking resemblance to Z-DNA in their helicity and jagged phosphate backbone. To further understand structural features of the LHG4s that define their left handedness, we have employed human-interpretable machine-learning methods to classify right- and left-handed G4s purely based on torsional angle analysis. Our results reveal the importance of the α, β, δ, and χ angles in left-handed structuring across both Z-DNAs and LHG4s. Our analysis may serve as the first step to understanding the conditions of formation for LHG4s and their potential biological relevance.
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Affiliation(s)
- Kevin Li
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| | - Liliya A Yatsunyk
- Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania
| | - Stephen Neidle
- UCL School of Pharmacy, University College London, London, United Kingdom.
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2
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Oh J, Jia T, Xu J, Chong J, Dervan PB, Wang D. RNA polymerase II trapped on a molecular treadmill: Structural basis of persistent transcriptional arrest by a minor groove DNA binder. Proc Natl Acad Sci U S A 2022; 119:e2114065119. [PMID: 35022237 PMCID: PMC8784135 DOI: 10.1073/pnas.2114065119] [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: 07/29/2021] [Accepted: 12/07/2021] [Indexed: 02/06/2023] Open
Abstract
Elongating RNA polymerase II (Pol II) can be paused or arrested by a variety of obstacles. These obstacles include DNA lesions, DNA-binding proteins, and small molecules. Hairpin pyrrole-imidazole (Py-Im) polyamides bind to the minor groove of DNA in a sequence-specific manner and induce strong transcriptional arrest. Remarkably, this Py-Im-induced Pol II transcriptional arrest is persistent and cannot be rescued by transcription factor TFIIS. In contrast, TFIIS can effectively rescue the transcriptional arrest induced by a nucleosome barrier. The structural basis of Py-Im-induced transcriptional arrest and why TFIIS cannot rescue this arrest remain elusive. Here we determined the X-ray crystal structures of four distinct Pol II elongation complexes (Pol II ECs) in complex with hairpin Py-Im polyamides as well as of the hairpin Py-Im polyamides-dsDNA complex. We observed that the Py-Im oligomer directly interacts with RNA Pol II residues, introduces compression of the downstream DNA duplex, prevents Pol II forward translocation, and induces Pol II backtracking. These results, together with biochemical studies, provide structural insight into the molecular mechanism by which Py-Im blocks transcription. Our structural study reveals why TFIIS fails to promote Pol II bypass of Py-Im-induced transcriptional arrest.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Tiezheng Jia
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Jun Xu
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093
| | - Peter B Dervan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125;
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093;
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093
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3
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Sequence-dependent structural properties of B-DNA: what have we learned in 40 years? Biophys Rev 2021; 13:995-1005. [DOI: 10.1007/s12551-021-00893-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 11/01/2021] [Indexed: 11/27/2022] Open
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4
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Battistini F, Dans PD, Terrazas M, Castellazzi CL, Portella G, Labrador M, Villegas N, Brun-Heath I, González C, Orozco M. The Impact of the HydroxyMethylCytosine epigenetic signature on DNA structure and function. PLoS Comput Biol 2021; 17:e1009547. [PMID: 34748533 PMCID: PMC8601608 DOI: 10.1371/journal.pcbi.1009547] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 11/18/2021] [Accepted: 10/10/2021] [Indexed: 12/30/2022] Open
Abstract
We present a comprehensive, experimental and theoretical study of the impact of 5-hydroxymethylation of DNA cytosine. Using molecular dynamics, biophysical experiments and NMR spectroscopy, we found that Ten-Eleven translocation (TET) dioxygenases generate an epigenetic variant with structural and physical properties similar to those of 5-methylcytosine. Experiments and simulations demonstrate that 5-methylcytosine (mC) and 5-hydroxymethylcytosine (hmC) generally lead to stiffer DNA than normal cytosine, with poorer circularization efficiencies and lower ability to form nucleosomes. In particular, we can rule out the hypothesis that hydroxymethylation reverts to unmodified cytosine physical properties, as hmC is even more rigid than mC. Thus, we do not expect dramatic changes in the chromatin structure induced by differences in physical properties between d(mCpG) and d(hmCpG). Conversely, our simulations suggest that methylated-DNA binding domains (MBDs), associated with repression activities, are sensitive to the substitution d(mCpG) ➔ d(hmCpG), while MBD3 which has a dual activation/repression activity is not sensitive to the d(mCpG) d(hmCpG) change. Overall, while gene activity changes due to cytosine methylation are the result of the combination of stiffness-related chromatin reorganization and MBD binding, those associated to 5-hydroxylation of methylcytosine could be explained by a change in the balance of repression/activation pathways related to differential MBD binding. In Eukaryotic cells, DNA epigenetic modifications play an important role in gene expression and regulation, and protein recognition. In this work we investigate the physical implications of cytosine 5-hydroxymethylation on DNA, its structural and flexibility differences with methylated and unmodified cytosine using molecular dynamics, biophysical experiments and NMR spectroscopy. In particular the effect of hydroxyl group on free energy of nucleosome and Methyl binding Protein (MBD) binding, comparing in silico and experimental data to shed light on the effect of the reduced flexibility and the direct protein-DNA recognition.
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Affiliation(s)
- Federica Battistini
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Pablo D. Dans
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Biological Sciences, CENUR Litoral Norte, Universidad de la República (UdelaR), Salto, Uruguay
- Functional Genomics Lab., Institut Pasteur of Montevideo, Montevideo, Uruguay
| | - Montserrat Terrazas
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Chiara L. Castellazzi
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Guillem Portella
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
- Chemistry Department, University of Cambridge, Cambridge, United Kingdom
| | - Mireia Labrador
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Núria Villegas
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Isabelle Brun-Heath
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Carlos González
- Instituto Química Física Rocasolano, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona). The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Biochemistry and Molecular Biology, University of Barcelona, Barcelona, Spain
- * E-mail:
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5
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Balaceanu A, Buitrago D, Walther J, Hospital A, Dans PD, Orozco M. Modulation of the helical properties of DNA: next-to-nearest neighbour effects and beyond. Nucleic Acids Res 2019; 47:4418-4430. [PMID: 30957854 PMCID: PMC6511876 DOI: 10.1093/nar/gkz255] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/23/2019] [Accepted: 03/30/2019] [Indexed: 12/21/2022] Open
Abstract
We used extensive molecular dynamics simulations to study the structural and dynamic properties of the central d(TpA) step in the highly polymorphic d(CpTpApG) tetranucleotide. Contrary to the assumption of the dinucleotide-model and its nearest neighbours (tetranucleotide-model), the properties of the central d(TpA) step change quite significantly dependent on the next-to-nearest (hexanucleotide) sequence context and in a few cases are modulated by even remote neighbours (beyond next-to-nearest from the central TpA). Our results highlight the existence of previously undescribed dynamical mechanisms for the transmission of structural information into the DNA and demonstrate the existence of certain sequences with special physical properties that can impact on the global DNA structure and dynamics.
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Affiliation(s)
- Alexandra Balaceanu
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Diana Buitrago
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Jürgen Walther
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Adam Hospital
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Pablo D Dans
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
| | - Modesto Orozco
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain.,Department of Biochemistry and Biomedicine, University of Barcelona, 08028 Barcelona, Spain
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6
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Gilski M, Zhao J, Kowiel M, Brzezinski D, Turner DH, Jaskolski M. Accurate geometrical restraints for Watson-Crick base pairs. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2019; 75:235-245. [PMID: 32830749 PMCID: PMC6457083 DOI: 10.1107/s2052520619002002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Accepted: 02/05/2019] [Indexed: 05/30/2023]
Abstract
Geometrical restraints provide key structural information for the determination of biomolecular structures at lower resolution by experimental methods such as crystallography or cryo-electron microscopy. In this work, restraint targets for nucleic acids bases are derived from three different sources and compared: small-molecule crystal structures in the Cambridge Structural Database (CSD), ultrahigh-resolution structures in the Protein Data Bank (PDB) and quantum-mechanical (QM) calculations. The best parameters are those based on CSD structures. After over two decades, the standard library of Parkinson et al. [(1996), Acta Cryst. D52, 57-64] is still valid, but improvements are possible with the use of the current CSD database. The CSD-derived geometry is fully compatible with Watson-Crick base pairs, as comparisons with QM results for isolated and paired bases clearly show that the CSD targets closely correspond to proper base pairing. While the QM results are capable of distinguishing between single and paired bases, their level of accuracy is, on average, nearly two times lower than for the CSD-derived targets when gauged by root-mean-square deviations from ultrahigh-resolution structures in the PDB. Nevertheless, the accuracy of QM results appears sufficient to provide stereochemical targets for synthetic base pairs where no reliable experimental structural information is available. To enable future tests for this approach, QM calculations are provided for isocytosine, isoguanine and the iCiG base pair.
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Affiliation(s)
- Miroslaw Gilski
- Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, 61-614, Poland
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland
| | - Jianbo Zhao
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
- Center for RNA Biology, University of Rochester, Rochester, NY 14627, USA
| | - Marcin Kowiel
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland
| | - Dariusz Brzezinski
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland
- Institute of Computing Science, Poznan University of Technology, Poznan, 60-965, Poland
- Center for Artificial Intelligence and Machine Learning, Poznan University of Technology, 60-965, Poland
| | - Douglas H. Turner
- Department of Chemistry, University of Rochester, Rochester, NY 14627, USA
- Center for RNA Biology, University of Rochester, Rochester, NY 14627, USA
| | - Mariusz Jaskolski
- Department of Crystallography, Faculty of Chemistry, A. Mickiewicz University, Poznan, 61-614, Poland
- Center for Biocrystallographic Research, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland
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7
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Sunami T, Chatake T, Kono H. DNA conformational transitions inferred from re-evaluation of m|F o| - D|F c| electron-density maps. Acta Crystallogr D Struct Biol 2017; 73:600-608. [PMID: 28695860 PMCID: PMC5505156 DOI: 10.1107/s2059798317007707] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 05/24/2017] [Indexed: 11/30/2022] Open
Abstract
Conformational flexibility of DNA plays important roles in biological processes such as transcriptional regulation and DNA packaging etc. To understand the mechanisms of these processes, it is important to analyse when, where and how DNA shows conformational variations. Recent analyses have indicated that conventional refinement methods do not always provide accurate models of crystallographic heterogeneities and that some information on polymorphism has been overlooked in previous crystallographic studies. In the present study, the m|Fo| - D|Fc| electron-density maps of double-helical DNA crystal structures were calculated at a resolution equal to or better than 1.5 Å and potential conformational transitions were found in 27% of DNA phosphates. Detailed analyses of the m|Fo| - D|Fc| peaks indicated that some of these unassigned densities correspond to ZI ↔ ZII or A/B → BI conformational transitions. A relationship was also found between ZI/ZII transitions and metal coordination in Z-DNA from the detected peaks. The present study highlights that frequent transitions of phosphate backbones occur even in crystals and that some of these transitions are affected by the local molecular environment.
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Affiliation(s)
- Tomoko Sunami
- Molecular Modeling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa 619-0215, Japan
| | - Toshiyuki Chatake
- Research Reactor Institute, Kyoto University, 2 Asashironishi, Kumatori, Osaka 590-0494, Japan
| | - Hidetoshi Kono
- Molecular Modeling and Simulation Group, National Institutes for Quantum and Radiological Science and Technology, 8-1-7 Umemidai, Kizugawa 619-0215, Japan
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8
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Zgarbová M, Jurečka P, Lankaš F, Cheatham TE, Šponer J, Otyepka M. Influence of BII Backbone Substates on DNA Twist: A Unified View and Comparison of Simulation and Experiment for All 136 Distinct Tetranucleotide Sequences. J Chem Inf Model 2017; 57:275-287. [PMID: 28059516 DOI: 10.1021/acs.jcim.6b00621] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reliable representation of the B-DNA base-pair step twist is one of the crucial requirements for theoretical modeling of DNA supercoiling and other biologically relevant phenomena in B-DNA. It has long been suspected that the twist is inaccurately described by current empirical force fields. Unfortunately, comparison of simulation results with experiments is not straightforward because of the presence of BII backbone substates, whose populations may differ in experimental and simulation ensembles. In this work, we provide a comprehensive view of the effect of BII substates on the overall B-DNA helix twist and show how to reliably compare twist values from experiment and simulation in two scenarios. First, for longer DNA segments freely moving in solution, we show that sequence-averaged twists of different BI/BII ensembles can be compared directly because of approximate cancellation of the opposing BII effects. Second, for sequence-specific data, such as a particular base-pair step or tetranucleotide twist, can be compared only for a clearly defined BI/BII backbone conformation. For the purpose of force field testing, we designed a compact set of fourteen 22-base-pair B-DNA duplexes (Set 14) containing all 136 distinct tetranucleotide sequences and carried out a total of 84 μs of molecular dynamics simulations, primarily with the OL15 force field. Our results show that the ff99bsc0εζOL1χOL4, parmbsc1, and OL15 force fields model the B-DNA helical twist in good agreement with X-ray and minicircle ligation experiments. The comprehensive understanding obtained regarding the effect of BII substates on the base-pair step geometry should aid meaningful comparisons of various conformational ensembles in future research.
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Affiliation(s)
- Marie Zgarbová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , 17 listopadu 12, 77146 Olomouc, Czech Republic
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , 17 listopadu 12, 77146 Olomouc, Czech Republic
| | - Filip Lankaš
- Laboratory of Informatics and Chemistry, University of Chemistry and Technology Prague , Technická 5, 16628 Prague, Czech Republic
| | - Thomas E Cheatham
- Department of Medicinal Chemistry, University of Utah , 30 South 2000 East, Skaggs 105, Salt Lake City, Utah 84112, United States
| | - Jiří Šponer
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , 17 listopadu 12, 77146 Olomouc, Czech Republic.,Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 61265 Brno, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , 17 listopadu 12, 77146 Olomouc, Czech Republic
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9
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Fromm M, Boulanouar O. Low energy electrons and ultra-soft X-rays irradiation of plasmid DNA. Technical innovations. Radiat Phys Chem Oxf Engl 1993 2016. [DOI: 10.1016/j.radphyschem.2016.05.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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10
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Rohner M, Medina-Molner A, Spingler B. N,N,O and N,O,N Meridional cis Coordination of Two Guanines to Copper(II) by d(CGCGCG)2. Inorg Chem 2016; 55:6130-40. [DOI: 10.1021/acs.inorgchem.6b00672] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Melanie Rohner
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Alfredo Medina-Molner
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Bernhard Spingler
- University of Zurich, Department of Chemistry, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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11
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Ammar FF, Hobaika Z, Abdel-Azeim S, Zargarian L, Maroun RG, Fermandjian S. A targeted DNA substrate mechanism for the inhibition of HIV-1 integrase by inhibitors with antiretroviral activity. FEBS Open Bio 2016; 6:234-50. [PMID: 27239438 PMCID: PMC4821353 DOI: 10.1002/2211-5463.12025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 11/25/2015] [Accepted: 12/16/2015] [Indexed: 12/21/2022] Open
Abstract
We recently reported that viral DNA could be the primary target of raltegravir (RAL), an efficient anti‐HIV‐1 drug, which acts by inhibiting integrase. To elucidate this mechanism, we conducted a comparative analysis of RAL and TB11, a diketoacid abandoned as an anti‐HIV‐1 drug for its weak efficiency and marked toxicity, and tested the effects of the catalytic cofactor Mg2+ (5 mm) on drug‐binding properties. We used circular dichroism and fluorescence to determine drug affinities for viral DNA long terminal repeats (LTRs) and peptides derived from the integrase active site and DNA retardation assays to assess drug intercalation into DNA base pairs. We found that RAL bound more tightly to LTR ends than did TB11 (a diketo acid bearing an azido group) and that Mg2+ significantly increased the affinity of both RAL and TB11. We also observed a good relationship between drug binding with processed LTR and strand transfer inhibition. This unusual type of inhibition was caused by Mg2+‐assisted binding of drugs to DNA substrate, rather than to enzyme. Notably, while RAL bound exclusively to the cleavable/cleaved site, TB11 further intercalated into DNA base pairs and interacted with the integrase‐derived peptides. These unwanted binding sites explain the weaker bioavailability and higher toxicity of TB11 compared with the more effective RAL.
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Affiliation(s)
- Farah F Ammar
- Centre d'Analyses et de Recherche UR EGFEM Faculté des Sciences Université Saint-Joseph Beirut Lebanon; LBPA, UMR8113 du CNRS Ecole Normale Supérieure de Cachan Cedex Cachan France
| | - Zeina Hobaika
- Centre d'Analyses et de Recherche UR EGFEM Faculté des Sciences Université Saint-Joseph Beirut Lebanon
| | - Safwat Abdel-Azeim
- LBPA, UMR8113 du CNRS Ecole Normale Supérieure de Cachan Cedex Cachan France
| | - Loussinée Zargarian
- LBPA, UMR8113 du CNRS Ecole Normale Supérieure de Cachan Cedex Cachan France
| | - Richard G Maroun
- Centre d'Analyses et de Recherche UR EGFEM Faculté des Sciences Université Saint-Joseph Beirut Lebanon
| | - Serge Fermandjian
- LBPA, UMR8113 du CNRS Ecole Normale Supérieure de Cachan Cedex Cachan France; Chemistry and Biology, Nucleo(s)tides and Immunology for Therapy UMR8601 CNRS Paris Cedex 06 France
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12
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Thirugnanasambandam A, Karthik S, Artheswari G, Gautham N. DNA polymorphism in crystals: three stable conformations for the decadeoxynucleotide d(GCATGCATGC). ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2016; 72:780-8. [PMID: 27303798 DOI: 10.1107/s2059798316006306] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 04/14/2016] [Indexed: 11/11/2022]
Abstract
High-resolution structures of DNA fragments determined using X-ray crystallography or NMR have provided descriptions of a veritable alphabet of conformations. They have also shown that DNA is a flexible molecule, with some sequences capable of adopting two different structures. Here, the first example is presented of a DNA fragment that can assume three different and distinct conformations in crystals. The decanucleotide d(GCATGCATGC) was previously reported to assume a single-stranded double-fold structure. In one of the two crystal structures described here the decamer assumes both the double-fold conformation and, simultaneously, the more conventional B-type double-helical structure. In the other crystal the sequence assumes the A-type double-helical conformation. These results, taken together with CD spectra, which were recorded as the decamer was titrated against four metal ions and spermine, indicate that the molecule may exist as a mixed population of structures in solution. Small differences in the environmental conditions, such as the concentration of metal ion, may decide which of these crystallizes out. The results also support the idea that it may be possible for DNA to change its structure to suit the binding requirements of proteins or drugs.
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Affiliation(s)
| | - Selvam Karthik
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Gunanithi Artheswari
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Namasivayam Gautham
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
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13
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Ramazanov RR, Maksimov DA, Kononov AI. Noncanonical Stacking Geometries of Nucleobases as a Preferred Target for Solar Radiation. J Am Chem Soc 2015; 137:11656-65. [DOI: 10.1021/jacs.5b05140] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Ruslan R. Ramazanov
- Department of Molecular Biophysics
and Polymer Physics, St. Petersburg State University, 7/9 Universitetskaya
nab., St. Petersburg 199034 Russia
| | - Dmitriy A. Maksimov
- Department of Molecular Biophysics
and Polymer Physics, St. Petersburg State University, 7/9 Universitetskaya
nab., St. Petersburg 199034 Russia
| | - Alexei I. Kononov
- Department of Molecular Biophysics
and Polymer Physics, St. Petersburg State University, 7/9 Universitetskaya
nab., St. Petersburg 199034 Russia
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14
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Acosta-Reyes FJ, Subirana JA, Pous J, Sánchez-Giraldo R, Condom N, Baldini R, Malinina L, Campos JL. Polymorphic crystal structures of an all-AT DNA dodecamer. Biopolymers 2014; 103:123-33. [DOI: 10.1002/bip.22565] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/17/2014] [Accepted: 09/23/2014] [Indexed: 12/12/2022]
Affiliation(s)
| | - Juan A. Subirana
- Departament d'Enginyeria Química; Universitat Politècnica de Catalunya; 08028 Barcelona Spain
| | - Joan Pous
- Plataforma Automatitzada de Cristal·lografia; IBMB-CSIC and Institut de Recerca Biomédica de Barcelona; 08028 Barcelona Spain
| | - Raquel Sánchez-Giraldo
- Departament d'Enginyeria Química; Universitat Politècnica de Catalunya; 08028 Barcelona Spain
| | - Núria Condom
- Departament d'Enginyeria Química; Universitat Politècnica de Catalunya; 08028 Barcelona Spain
| | - Roberto Baldini
- Departament d'Enginyeria Química; Universitat Politècnica de Catalunya; 08028 Barcelona Spain
| | - Lucy Malinina
- Structural Biology Unit, CIC bioGUNE; Technology Park of Bizkaia; 48160 Derio Bilbao Spain
| | - J. Lourdes Campos
- Departament d'Enginyeria Química; Universitat Politècnica de Catalunya; 08028 Barcelona Spain
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15
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Dans PD, Faustino I, Battistini F, Zakrzewska K, Lavery R, Orozco M. Unraveling the sequence-dependent polymorphic behavior of d(CpG) steps in B-DNA. Nucleic Acids Res 2014; 42:11304-20. [PMID: 25223784 PMCID: PMC4191396 DOI: 10.1093/nar/gku809] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 11/12/2022] Open
Abstract
We have made a detailed study of one of the most surprising sources of polymorphism in B-DNA: the high twist/low twist (HT/LT) conformational change in the d(CpG) base pair step. Using extensive computations, complemented with database analysis, we were able to characterize the twist polymorphism in the d(CpG) step in all the possible tetranucleotide environment. We found that twist polymorphism is coupled with BI/BII transitions, and, quite surprisingly, with slide polymorphism in the neighboring step. Unexpectedly, the penetration of cations into the minor groove of the d(CpG) step seems to be the key element in promoting twist transitions. The tetranucleotide environment also plays an important role in the sequence-dependent d(CpG) polymorphism. In this connection, we have detected a previously unexplored intramolecular C-H···O hydrogen bond interaction that stabilizes the low twist state when 3'-purines flank the d(CpG) step. This work explains a coupled mechanism involving several apparently uncorrelated conformational transitions that has only been partially inferred by earlier experimental or theoretical studies. Our results provide a complete description of twist polymorphism in d(CpG) steps and a detailed picture of the molecular choreography associated with this conformational change.
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Affiliation(s)
- Pablo Daniel Dans
- Joint BSC-CRG-IRB Research Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Ignacio Faustino
- Joint BSC-CRG-IRB Research Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Federica Battistini
- Joint BSC-CRG-IRB Research Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain
| | - Krystyna Zakrzewska
- Bases Moléculaires et Structurales des Systèmes Infectieux, Univ. Lyon I/CNRS UMR 5086, IBCP, 7 Passage du Vercors, Lyon 69367, France
| | - Richard Lavery
- Bases Moléculaires et Structurales des Systèmes Infectieux, Univ. Lyon I/CNRS UMR 5086, IBCP, 7 Passage du Vercors, Lyon 69367, France
| | - Modesto Orozco
- Joint BSC-CRG-IRB Research Program in Computational Biology, Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain Departament de Bioquimica, Facultat de Biologia, Avgda Diagonal 647, Barcelona 08028, Spain
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16
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Zubatiuk TA, Shishkin OV, Gorb L, Hovorun DM, Leszczynski J. B-DNA characteristics are preserved in double stranded d(A)3·d(T)3 and d(G)3·d(C)3 mini-helixes: conclusions from DFT/M06-2X study. Phys Chem Chem Phys 2014; 15:18155-66. [PMID: 24065071 DOI: 10.1039/c3cp51584b] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We report the results of the first comprehensive DFT study on the d(A)3·d(T)3 and d(G)3·d(C)3 nucleic acid duplexes. The ability of mini-helixes to preserve the conformation of B-DNA in the gas phase and under the influence of such factors as: solvent, uncompensated charge, and counter-ions was evaluated using M06-2X functional with 6-31G(d,p) basis set. The accuracy of the models was ascertained based on their ability to reproduce key structural features of natural B-DNA. Analysis of the helicity suggests that the helical conformations adopt geometrical parameters which are close to those of the B-DNA form. The torsion angles fall somewhere between the values observed for BI/BII conformational classes. The comparative analysis of parameters of isolated Watson-Crick base pairs versus B-DNA-like conformations indicates the same tendency of base-pair polarization and hydration. Specifically, effects of polarization of nucleobases in continuum type dielectric medium mimicking water are stronger than those caused by the presence of backbone. Polar environment as well as the presence of counterions stabilizes duplexes, facilitating helix formation. Substantial conformational changes of nucleotides upon duplex formation decrease the binding energy. In spite of structural and energetic changes, the placement of a mini-helix into the gas phase does not lead to significant disruption of the structure. On the contrary, the duplex preserves its helicity and the strands remain bound.
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Affiliation(s)
- Tetiana A Zubatiuk
- Division of Functional Materials Chemistry, SSI "Institute for Single Crystals" National Academy of Science of Ukraine, 60 Lenina Ave., Kharkiv, 61001, Ukraine
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17
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Xiao S, Zhu H, Wang L, Liang H. DNA conformational flexibility study using phosphate backbone neutralization model. SOFT MATTER 2014; 10:1045-1055. [PMID: 24983118 DOI: 10.1039/c3sm52345d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Due to the critical role of DNA in the processes of the cell cycle, the structural and physicochemical properties of DNA have long been of concern. In the present work, the effect of interplay between the DNA duplex and metal ions in solution on the DNA structure and conformational flexibility is studied by comparing the structure and dynamic conformational behavior of a duplex in a normal form and its “null isomer” using molecular dynamics methods. It was found that the phosphate neutralization changes the cation atmosphere around the DNA duplex greatly, increases the major groove width, decreases the minor groove width, and reduces the global bending direction preference. We also noted that the probability of BI phosphate linkages increases significantly because of the charge reduction in the backbone phosphate groups. More importantly, we found that the electrostatic effect on the DNA conformational flexibility is dependent on the sequence; that is, the phosphate backbone neutralization induces the global dynamic bending to be less flexible for GC-rich sequences but more flexible for AT-rich sequences.
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18
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Szulik MW, Voehler MW, Ganguly M, Gold B, Stone MP. Site-specific stabilization of DNA by a tethered major groove amine, 7-aminomethyl-7-deaza-2'-deoxyguanosine. Biochemistry 2013; 52:7659-68. [PMID: 24131376 PMCID: PMC3812902 DOI: 10.1021/bi400695r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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A cationic
7-aminomethyl-7-deaza-2′-deoxyguanosine (7amG)
was incorporated site-specifically into the self-complementary duplex
d(G1A2G3A4X5C6G7C8T9C10T11C12)2 (X = 7amG). This construct placed two positively charged amines adjacent
to the major groove edges of two symmetry-related guanines, providing
a model for probing how cation binding in the major groove modulates
the structure and stability of DNA. Molecular dynamics calculations
restrained by nuclear magnetic resonance (NMR) data revealed that
the tethered cationic amines were in plane with the modified base
pairs. The tethered amines did not form salt bridges to the phosphodiester
backbone. There was also no indication of the amines being capable
of hydrogen bonding to flanking DNA bases. NMR spectroscopy as a function
of temperature revealed that the X5 imino resonance remained
sharp at 55 °C. Additionally, two 5′-neighboring base
pairs, A4:T9 and G3:C10, were stabilized with respect to the exchange of their imino protons
with solvent. The equilibrium constant for base pair opening at the
A4:T9 base pair determined by magnetization
transfer from water in the absence and presence of added ammonia base
catalyst decreased for the modified duplex compared to that of the
A4:T9 base pair in the unmodified duplex, which
confirmed that the overall fraction of the A4:T9 base pair in the open state of the modified duplex decreased. This
was also observed for the G3:C10 base pair,
where αKop for the G3:C10 base pair in the modified duplex was 3.0 × 106 versus 4.1 × 106 for the same base pair in
the unmodified duplex. In contrast, equilibrium constants for base
pair opening at the X5:C8 and C6:G7 base pairs did not change at 15 °C. These results argue
against the notion that electrostatic interactions with DNA are entirely
entropic and suggest that major groove cations can stabilize DNA via
enthalpic contributions to the free energy of duplex formation.
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Affiliation(s)
- Marta W Szulik
- Department of Chemistry and Center for Structural Biology, Vanderbilt University , Nashville, Tennessee 37235, United States
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19
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Robbins TJ, Wang Y. Effect of initial ion positions on the interactions of monovalent and divalent ions with a DNA duplex as revealed with atomistic molecular dynamics simulations. J Biomol Struct Dyn 2012; 31:1311-23. [PMID: 23153112 DOI: 10.1080/07391102.2012.732344] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Monovalent (Na(+)) and divalent (Mg(2+)) ion distributions around the Dickerson-Drew dodecamer were studied by atomistic molecular dynamics (MD) simulations with AMBER molecular modeling software. Different initial placements of ions were tried and the resulting effects on the ion distributions around DNA were investigated. For monovalent ions, results were found to be nearly independent of initial cation coordinates. However, Mg(2+) ions demonstrated a strong initial coordinate dependent behavior. While some divalent ions initially placed near the DNA formed essentially permanent direct coordination complexes with electronegative DNA atoms, Mg(2+) ions initially placed further away from the duplex formed a full, nonexchanging, octahedral first solvation shell. These fully solvated cations were still capable of binding with DNA with events lasting up to 20 ns, and in comparison were bound much longer than Na(+) ions. Force field parameters were also investigated with modest and little differences arising from ion (ions94 and ions08) and nucleic acid description (ff99, ff99bsc0, and ff10), respectively. Based on known Mg(2+) ion solvation structure, we conclude that in most cases Mg(2+) ions retain their first solvation shell, making only solvent-mediated contacts with DNA duplex. The proper way to simulate Mg(2+) ions around DNA duplex, therefore, should begin with ions placed in the bulk water.
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Affiliation(s)
- Timothy J Robbins
- a Department of Chemistry , University of Memphis , Memphis , TN , 38152 , USA
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20
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Chenoweth DM, Meier JL, Dervan PB. Pyrrole-imidazole polyamides distinguish between double-helical DNA and RNA. Angew Chem Int Ed Engl 2012; 52:415-8. [PMID: 22987334 DOI: 10.1002/anie.201205775] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Indexed: 12/14/2022]
Abstract
Groove specificity: pyrrole-imidazole polyamides are well-known for their specific interactions with the minor groove of DNA. However, polyamides do not show similar binding to duplex RNA, and a structural rationale for the molecular-level discrimination of nucleic acid duplexes by minor-groove-binding ligands is presented.
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Affiliation(s)
- David M Chenoweth
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, 91125, USA
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21
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Chenoweth DM, Meier JL, Dervan PB. Pyrrole-Imidazole Polyamides Distinguish Between Double-Helical DNA and RNA. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201205775] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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22
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Guéroult M, Boittin O, Mauffret O, Etchebest C, Hartmann B. Mg2+ in the major groove modulates B-DNA structure and dynamics. PLoS One 2012; 7:e41704. [PMID: 22844516 PMCID: PMC3402463 DOI: 10.1371/journal.pone.0041704] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Accepted: 06/25/2012] [Indexed: 12/12/2022] Open
Abstract
This study investigates the effect of Mg(2+) bound to the DNA major groove on DNA structure and dynamics. The analysis of a comprehensive dataset of B-DNA crystallographic structures shows that divalent cations are preferentially located in the DNA major groove where they interact with successive bases of (A/G)pG and the phosphate group of 5'-CpA or TpG. Based on this knowledge, molecular dynamics simulations were carried out on a DNA oligomer without or with Mg(2+) close to an ApG step. These simulations showed that the hydrated Mg(2+) forms a stable intra-strand cross-link between the two purines in solution. ApG generates an electrostatic potential in the major groove that is particularly attractive for cations; its intrinsic conformation is well-adapted to the formation of water-mediated hydrogen bonds with Mg(2+). The binding of Mg(2+) modulates the behavior of the 5'-neighboring step by increasing the BII (ε-ζ>0°) population of its phosphate group. Additional electrostatic interactions between the 5'-phosphate group and Mg(2+) strengthen both the DNA-cation binding and the BII character of the 5'-step. Cation binding in the major groove may therefore locally influence the DNA conformational landscape, suggesting a possible avenue for better understanding how strong DNA distortions can be stabilized in protein-DNA complexes.
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Affiliation(s)
- Marc Guéroult
- Dynamique des Structures et Interactions des Macromolécules Biologiques, UMR 665 INSERM-Université Paris Diderot, Sorbonne Paris Cité, Institut National de la Transfusion Sanguine, Paris, France
- Laboratoire de Biochimie Théorique, UPR 9080 CNRS, Institut de Biologie Physico-Chimique, Paris, France
| | - Olivier Boittin
- Dynamique des Structures et Interactions des Macromolécules Biologiques, UMR 665 INSERM-Université Paris Diderot, Sorbonne Paris Cité, Institut National de la Transfusion Sanguine, Paris, France
| | - Oliver Mauffret
- Laboratoire de Biologie et Pharmacologie Appliquée, UMR 8113 CNRS-ENS de Cachan, Cachan, France
| | - Catherine Etchebest
- Dynamique des Structures et Interactions des Macromolécules Biologiques, UMR 665 INSERM-Université Paris Diderot, Sorbonne Paris Cité, Institut National de la Transfusion Sanguine, Paris, France
| | - Brigitte Hartmann
- Dynamique des Structures et Interactions des Macromolécules Biologiques, UMR 665 INSERM-Université Paris Diderot, Sorbonne Paris Cité, Institut National de la Transfusion Sanguine, Paris, France
- Laboratoire de Biologie et Pharmacologie Appliquée, UMR 8113 CNRS-ENS de Cachan, Cachan, France
- * E-mail:
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23
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Krepl M, Zgarbová M, Stadlbauer P, Otyepka M, Banáš P, Koča J, Cheatham TE, Jurečka P, Šponer J. Reference simulations of noncanonical nucleic acids with different χ variants of the AMBER force field: quadruplex DNA, quadruplex RNA and Z-DNA. J Chem Theory Comput 2012; 8:2506-2520. [PMID: 23197943 PMCID: PMC3506181 DOI: 10.1021/ct300275s] [Citation(s) in RCA: 200] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Refinement of empirical force fields for nucleic acids requires their extensive testing using as wide range of systems as possible. However, finding unambiguous reference data is not easy. In this paper, we analyze four systems which we suggest should be included in standard portfolio of molecules to test nucleic acids force fields, namely, parallel and antiparallel stranded DNA guanine quadruplex stems, RNA quadruplex stem, and Z-DNA. We highlight parameters that should be monitored to assess the force field performance. The work is primarily based on 8.4 μs of 100-250 ns trajectories analyzed in detail followed by 9.6 μs of additional selected back up trajectories that were monitored to verify that the results of the initial analyses are correct. Four versions of the Cornell et al. AMBER force field are tested, including an entirely new parmχ(OL4) variant with χ dihedral specifically reparametrized for DNA molecules containing syn nucleotides. We test also different water models and ion conditions. While improvement for DNA quadruplexes is visible, the force fields still do not fully represent the intricate Z-DNA backbone conformation.
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Affiliation(s)
- Miroslav Krepl
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Marie Zgarbová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Petr Stadlbauer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Jaroslav Koča
- CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
- National Center for Biomolecular Research, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Thomas E. Cheatham
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University, tr. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno, Czech Republic
- CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
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24
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Mandal PK, Venkadesh S, Gautham N. Structure of the tetradecanucleotide d(CCCCGGTACCGGGG)2 as an A-DNA duplex. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:393-9. [PMID: 22505405 PMCID: PMC3325805 DOI: 10.1107/s174430911200869x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 02/27/2012] [Indexed: 11/10/2022]
Abstract
The crystal structure of the tetradecanucleotide sequence d(CCCCGGTACCGGGG)(2) has been determined at 2.5 Å resolution in the tetragonal space group P4(1). This sequence was designed with the expectation of a four-way junction. However, the sequence crystallized as an A-DNA duplex and represents more than one full turn of the A-helix. The crystallographic asymmetric unit consists of one tetradecanucleotide duplex. The structural parameters of the A-type DNA duplex structure and the crystal-packing arrangement are described. One Mn(2+) ion was identified with direct coordination to the N7 position of G(13) and a water molecule at the major-groove side of the C(2)·G(13) base pair.
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Affiliation(s)
- Pradeep Kumar Mandal
- C. A. S. in Crystallography and Biophysics, University of Madras, Guindy, Chennai 600 025, India
| | - Sarkarai Venkadesh
- C. A. S. in Crystallography and Biophysics, University of Madras, Guindy, Chennai 600 025, India
| | - Namasivayam Gautham
- C. A. S. in Crystallography and Biophysics, University of Madras, Guindy, Chennai 600 025, India
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25
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Abstract
Metal ions play a key role in nucleic acid structure and activity. Elucidation of the rules that govern the binding of metal ions is therefore an essential step for better understanding of the nucleic acid functions. This review is as an update to a preceding one (Metal Ions Biol. Syst., 1996, 32, 91-134), in which we offered a general view of metal ion interactions with mono-, di-, tri-, and oligonucleotides in the solid state, based on their crystal structures reported before 1994. In this chapter, we survey all the crystal structures of metal ion complexes with nucleotides involving oligonucleotides reported after 1994 and we have tried to uncover new characteristic metal bonding patterns for mononucleotides and oligonucleotides with A-RNA and A/B/Z-DNA fragments that form duplexes. We do not cover quadruplexes, duplexes with metal-mediated base-pairs, tRNAs, rRNAs in ribosome, ribozymes, and nucleic acid-drug and -protein complexes. Factors that affect metal binding to mononucleotides and oligonucleotide duplexes are also dealt with.
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26
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Maehigashi T, Hsiao C, Woods KK, Moulaei T, Hud NV, Williams LD. B-DNA structure is intrinsically polymorphic: even at the level of base pair positions. Nucleic Acids Res 2011; 40:3714-22. [PMID: 22180536 PMCID: PMC3333872 DOI: 10.1093/nar/gkr1168] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Increasingly exact measurement of single crystal X-ray diffraction data offers detailed characterization of DNA conformation, hydration and electrostatics. However, instead of providing a more clear and unambiguous image of DNA, highly accurate diffraction data reveal polymorphism of the DNA atomic positions and conformation and hydration. Here we describe an accurate X-ray structure of B-DNA, painstakingly fit to a multistate model that contains multiple competing positions of most of the backbone and of entire base pairs. Two of ten base-pairs of CCAGGCCTGG are in multiple states distinguished primarily by differences in slide. Similarly, all the surrounding ions are seen to fractionally occupy discrete competing and overlapping sites. And finally, the vast majority of water molecules show strong evidence of multiple competing sites. Conventional resolution appears to give a false sense of homogeneity in conformation and interactions of DNA. In addition, conventional resolution yields an average structure that is not accurate, in that it is different from any of the multiple discrete structures observed at high resolution. Because base pair positional heterogeneity has not always been incorporated into model-building, even some high and ultrahigh-resolution structures of DNA do not indicate the full extent of conformational polymorphism.
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Affiliation(s)
- Tatsuya Maehigashi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
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27
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Russo Krauss I, Merlino A, Giancola C, Randazzo A, Mazzarella L, Sica F. Thrombin-aptamer recognition: a revealed ambiguity. Nucleic Acids Res 2011; 39:7858-67. [PMID: 21715374 PMCID: PMC3177225 DOI: 10.1093/nar/gkr522] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Aptamers are structured oligonucleotides that recognize molecular targets and can function as direct protein inhibitors. The best-known example is the thrombin-binding aptamer, TBA, a single-stranded 15-mer DNA that inhibits the activity of thrombin, the key enzyme of coagulation cascade. TBA folds as a G-quadruplex structure, as proved by its NMR structure. The X-ray structure of the complex between TBA and human α-thrombin was solved at 2.9-Å resolution, but did not provide details of the aptamer conformation and the interactions with the protein molecule. TBA is rapidly processed by nucleases. To improve the properties of TBA, a number of modified analogs have been produced. In particular, a modified TBA containing a 5′-5′ polarity inversion site, mTBA, has higher stability and higher affinity toward thrombin with respect to TBA, although it has a lower inhibitory activity. We present the crystal structure of the thrombin–mTBA complex at 2.15-Å resolution; the resulting model eventually provides a clear picture of thrombin–aptamers interaction, and also highlights the structural bases of the different properties of TBA and mTBA. Our findings open the way for a rational design of modified aptamers with improved potency as anticoagulant drugs.
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28
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Abstract
A new functional bifacial nucleoside derived from 7-aminopyrimido[4,5-d]pyrimidine-2,4(1H,3H)-dione, a Janus-type nucleobase, has been synthesized and incorporated into DNA oligonucleotides. The nucleobase, having self-complementary H-bonding faces, mimics both T and A and engages in the corresponding Watson-Crick-like base pairs, forming stable duplexes.
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Affiliation(s)
- Dongwon Shin
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358
| | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358
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29
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Brzezinski K, Brzuszkiewicz A, Dauter M, Kubicki M, Jaskolski M, Dauter Z. High regularity of Z-DNA revealed by ultra high-resolution crystal structure at 0.55 A. Nucleic Acids Res 2011; 39:6238-48. [PMID: 21459852 PMCID: PMC3152349 DOI: 10.1093/nar/gkr202] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The crystal structure of a Z-DNA hexamer duplex d(CGCGCG)(2) determined at ultra high resolution of 0.55 Å and refined without restraints, displays a high degree of regularity and rigidity in its stereochemistry, in contrast to the more flexible B-DNA duplexes. The estimations of standard uncertainties of all individually refined parameters, obtained by full-matrix least-squares optimization, are comparable with values that are typical for small-molecule crystallography. The Z-DNA model generated with ultra high-resolution diffraction data can be used to revise the stereochemical restraints applied in lower resolution refinements. Detailed comparisons of the stereochemical library values with the present accurate Z-DNA parameters, shows in general a good agreement, but also reveals significant discrepancies in the description of guanine-sugar valence angles and in the geometry of the phosphate groups.
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Affiliation(s)
- Krzysztof Brzezinski
- Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439, USA
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30
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Chenoweth DM, Dervan PB. Structural basis for cyclic Py-Im polyamide allosteric inhibition of nuclear receptor binding. J Am Chem Soc 2011; 132:14521-9. [PMID: 20812704 PMCID: PMC2954530 DOI: 10.1021/ja105068b] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
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Pyrrole-imidazole polyamides are a class of small molecules that can be programmed to bind a broad repertoire of DNA sequences, disrupt transcription factor−DNA interfaces, and modulate gene expression pathways in cell culture experiments. In this paper we describe a high-resolution X-ray crystal structure of a β-amino turn-linked eight-ring cyclic Py-Im polyamide bound to the central six base pairs of the sequence d(5′-CCAGTACTGG-3′)2, revealing significant modulation of DNA shape. We compare the DNA structural perturbations induced by DNA-binding transcripton factors, androgen receptor and glucocorticoid receptor, in the major groove to those induced by cyclic polyamide binding in the minor groove. The cyclic polyamide is an allosteric modulator that perturbs the DNA structure in such a way that nuclear receptor protein binding is no longer compatible. This allosteric perturbation of the DNA helix provides a molecular basis for disruption of transcription factor−DNA interfaces by small molecules, a minimum step in chemical control of gene networks.
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Affiliation(s)
- David M Chenoweth
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
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31
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Grokhovsky SL, Il'icheva IA, Nechipurenko DY, Golovkin MV, Panchenko LA, Polozov RV, Nechipurenko YD. Sequence-specific ultrasonic cleavage of DNA. Biophys J 2011; 100:117-25. [PMID: 21190663 PMCID: PMC3010002 DOI: 10.1016/j.bpj.2010.10.052] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2010] [Revised: 10/15/2010] [Accepted: 10/19/2010] [Indexed: 10/18/2022] Open
Abstract
We investigated the phenomenon of ultrasonic cleavage of DNA by analyzing a large set of cleavage patterns of DNA restriction fragments using polyacrylamide gel electrophoresis. The cleavage intensity of individual phosphodiester bonds was found to depend on the nucleotide sequence and the position of the bond with respect to the ends of the fragment. The relative intensities of cleavage of the central phosphodiester bond in 16 dinucleotides and 256 tetranucleotides were determined by multivariate statistical analysis. We observed a remarkable enhancement of the mean values of the relative intensities of cleavage (cleavage rates) in phosphodiester bonds following deoxycytidine, which diminished in the row of dinucleotides: d(CpG) > d(CpA) > d(CpT) >> d(CpC). The cleavage rates for all pairs of complementary dinucleotides were significantly different from each other. The effect of flanking nucleotides in tetranucleotides on cleavage rates of all 16 types of central dinucleotides was also statistically significant. The sequence-dependent ultrasonic cleavage rates of dinucleotides are consistent with reported data on the intensity of the conformational motion of their 5'-deoxyribose. As a measure of local conformational dynamics, cleavage rates may be useful for characterizing functional regions of the genome.
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Affiliation(s)
- Sergei L Grokhovsky
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
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Mládek A, Šponer JE, Jurečka P, Banáš P, Otyepka M, Svozil D, Šponer J. Conformational Energies of DNA Sugar−Phosphate Backbone: Reference QM Calculations and a Comparison with Density Functional Theory and Molecular Mechanics. J Chem Theory Comput 2010. [DOI: 10.1021/ct1004593] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Arnošt Mládek
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
| | - Judit E. Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
| | - Petr Jurečka
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
| | - Pavel Banáš
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
| | - Michal Otyepka
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
| | - Daniel Svozil
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Physical Chemistry, Faculty of Science, Palacký University, 771 46 Olomouc, Czech Republic, Laboratory of Informatics and Chemistry, Faculty of Chemical Technology, Institute of Chemical Technology, Technická 3, 166 28 Prague 6, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6,
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Wu B, Davey CA. Using soft X-rays for a detailed picture of divalent metal binding in the nucleosome. J Mol Biol 2010; 398:633-40. [PMID: 20350553 DOI: 10.1016/j.jmb.2010.03.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 03/04/2010] [Accepted: 03/19/2010] [Indexed: 11/17/2022]
Abstract
Divalent metals associate with DNA in a site-selective manner, which can influence nucleosome positioning, mobility, compaction, and recognition by nuclear factors. We previously characterized divalent metal binding in the nucleosome core using hard (short-wavelength) X-rays allowing high-resolution crystallographic determination of the strongest affinity sites, which revealed that Mn(2+) associates with the DNA major groove in a sequence- and conformation-dependent manner. In this study, we obtained diffraction data with soft X-rays at the Mn(2+) absorption edge for a core particle crystal in the presence of 10 mM MnSO(4), mimicking prevailing Mg(2+) concentration in the nucleus. This provides an exceptional view of counterion binding in the nucleosome through identification of 45 divalent metal binding sites. In addition to that at the well-characterized major interparticle interface, only one other histone-divalent metal binding site is found, which corresponds to a symmetry-related counterpart on the 'free' H2B alpha1 helix C-terminus. This emphasizes the importance of the alpha-helix dipole in ion binding and suggests that the H2B motif may serve as a nucleation site in nucleosome compaction. The 43 sites associated with the DNA are characterized by (1) high-affinity direct coordination at the most electrostatically favorable major groove locations, (2) metal hydrate binding to the major groove, (3) direct coordination to phosphate groups at sites of high charge density, (4) metal hydrate binding in the minor groove, or (5) metal hydrate-divalent anion pairing. Metal hydrates are found within the minor groove only at locations displaying a narrow range of high-intermediate width and to which histone N-terminal tails are not associated or proximal. This indicates that divalent metals and histone tails can both collaborate and compete in minor groove association, which sheds light on nucleosome solubility and chromatin compaction behavior.
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Affiliation(s)
- Bin Wu
- Division of Structural and Computational Biology, School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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Hobaika Z, Zargarian L, Boulard Y, Maroun RG, Mauffret O, Fermandjian S. Specificity of LTR DNA recognition by a peptide mimicking the HIV-1 integrase {alpha}4 helix. Nucleic Acids Res 2010; 37:7691-700. [PMID: 19808934 PMCID: PMC2794180 DOI: 10.1093/nar/gkp824] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
HIV-1 integrase integrates retroviral DNA through 3′-processing and strand transfer reactions in the presence of a divalent cation (Mg2+ or Mn2+). The α4 helix exposed at the catalytic core surface is essential to the specific recognition of viral DNA. To define group determinants of recognition, we used a model composed of a peptide analogue of the α4 helix, oligonucleotides mimicking processed and unprocessed U5 LTR end and 5 mM Mg2+. Circular dichroism, fluorescence and NMR experiments confirmed the implication of the α4 helix polar/charged face in specific and non-specific bindings to LTR ends. The specific binding requires unprocessed LTR ends—i.e. an unaltered 3′-processing site CA↓GT3′—and is reinforced by Mg2+ (Kd decreases from 2 to 0.8 nM). The latter likely interacts with the ApG and GpT3′ steps of the 3′-processing site. With deletion of GT3′, only persists non-specific binding (Kd of 100 μM). Proton chemical shift deviations showed that specific binding need conserved amino acids in the α4 helix and conserved nucleotide bases and backbone groups at LTR ends. We suggest a conserved recognition mechanism based on both direct and indirect readout and which is subject to evolutionary pressure.
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Affiliation(s)
- Zeina Hobaika
- Laboratoire de Biotechnologies et Pharmacologie génétique Appliquée (LBPA), UMR 8113 CNRS, Ecole Normale Supérieure de Cachan, 61 Avenue du Président Wilson, 94235 Cachan Cedex, France
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Hänsel R, Foldynová-Trantírková S, Löhr F, Buck J, Bongartz E, Bamberg E, Schwalbe H, Dötsch V, Trantírek L. Evaluation of parameters critical for observing nucleic acids inside living Xenopus laevis oocytes by in-cell NMR spectroscopy. J Am Chem Soc 2010; 131:15761-8. [PMID: 19824671 DOI: 10.1021/ja9052027] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In-cell NMR spectroscopy of proteins in different cellular environments is a well-established technique that, however, has not been applied to nucleic acids so far. Here, we show that isotopically labeled DNA and RNA can be observed inside the eukaryotic environment of Xenopus laevis oocytes by in-cell NMR spectroscopy. One limiting factor for the observation of nucleic acids in Xenopus oocytes is their reduced stability. We demonstrate that chemical modification of DNA and RNA can protect them from degradation and can significantly enhance their lifetime. Finally, we show that the imino region of the NMR spectrum is devoid of any oocyte background signals enabling the detection even of isotopically nonlabeled molecules.
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Affiliation(s)
- Robert Hänsel
- Institute of Biophysical Chemistry, Goethe-University, Max-von-Laue Str. 9, 60438 Frankfurt am Main, Germany
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Schnieders MJ, Fenn TD, Pande VS, Brunger AT. Polarizable atomic multipole X-ray refinement: application to peptide crystals. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2009; 65:952-65. [PMID: 19690373 PMCID: PMC2733883 DOI: 10.1107/s0907444909022707] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 06/13/2009] [Indexed: 11/26/2022]
Abstract
Recent advances in computational chemistry have produced force fields based on a polarizable atomic multipole description of biomolecular electrostatics. In this work, the Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) force field is applied to restrained refinement of molecular models against X-ray diffraction data from peptide crystals. A new formalism is also developed to compute anisotropic and aspherical structure factors using fast Fourier transformation (FFT) of Cartesian Gaussian multipoles. Relative to direct summation, the FFT approach can give a speedup of more than an order of magnitude for aspherical refinement of ultrahigh-resolution data sets. Use of a sublattice formalism makes the method highly parallelizable. Application of the Cartesian Gaussian multipole scattering model to a series of four peptide crystals using multipole coefficients from the AMOEBA force field demonstrates that AMOEBA systematically underestimates electron density at bond centers. For the trigonal and tetrahedral bonding geometries common in organic chemistry, an atomic multipole expansion through hexadecapole order is required to explain bond electron density. Alternatively, the addition of interatomic scattering (IAS) sites to the AMOEBA-based density captured bonding effects with fewer parameters. For a series of four peptide crystals, the AMOEBA-IAS model lowered R(free) by 20-40% relative to the original spherically symmetric scattering model.
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Affiliation(s)
| | - Timothy D. Fenn
- Department of Molecular and Cellular Physiology, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, USA
| | | | - Axel T. Brunger
- Department of Molecular and Cellular Physiology, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, USA
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Khuu P, Ho PS. A rare nucleotide base tautomer in the structure of an asymmetric DNA junction. Biochemistry 2009; 48:7824-32. [PMID: 19580331 PMCID: PMC2761035 DOI: 10.1021/bi900829b] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The single-crystal structure of a DNA Holliday junction assembled from four unique sequences shows a structure that conforms to the general features of models derived from similar constructs in solution. The structure is a compact stacked-X form junction with two sets of stacked B-DNA-type arms that coaxially stack to form semicontinuous duplexes interrupted only by the crossing of the junction. These semicontinuous helices are related by a right-handed rotation angle of 56.5 degrees, which is nearly identical to the 60 degree angle in the solution model but differs from the more shallow value of approximately 40 degrees for previous crystal structures of symmetric junctions that self-assemble from single identical inverted-repeat sequences. This supports the model in which the unique set of intramolecular interactions at the trinucleotide core of the crossing strands, which are not present in the current asymmetric junction, affects both the stability and geometry of the symmetric junctions. An unexpected result, however, is that a highly wobbled A.T base pair, which is ascribed here to a rare enol tautomer form of the thymine, was observed at the end of a CCCC/GGGG sequence within the stacked B-DNA arms of this 1.9 A resolution structure. We suggest that the junction itself is not responsible for this unusual conformation but served as a vehicle for the study of this CG-rich sequence as a B-DNA duplex, mimicking the form that would be present in a replication complex. The existence of this unusual base lends credence to and defines a sequence context for the "rare tautomer hypothesis" as a mechanism for inducing transition mutations during DNA replication.
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Affiliation(s)
- Patricia Khuu
- Department of Biochemistry and Biophysics, ALS 2011, Oregon State University, Corvallis, OR 97331
| | - P. Shing Ho
- Department of Biochemistry and Biophysics, ALS 2011, Oregon State University, Corvallis, OR 97331
- Department of Biochemistry and Molecular Biology, 1870 Campus Delivery, Colorado State University, Fort Collins, CO 80523
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Millonig H, Pous J, Gouyette C, Subirana JA, Campos JL. The interaction of manganese ions with DNA. J Inorg Biochem 2009; 103:876-80. [DOI: 10.1016/j.jinorgbio.2009.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 03/10/2009] [Accepted: 03/16/2009] [Indexed: 12/01/2022]
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Marathe A, Karandur D, Bansal M. Small local variations in B-form DNA lead to a large variety of global geometries which can accommodate most DNA-binding protein motifs. BMC STRUCTURAL BIOLOGY 2009; 9:24. [PMID: 19393049 PMCID: PMC2687451 DOI: 10.1186/1472-6807-9-24] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 04/24/2009] [Indexed: 01/01/2023]
Abstract
BACKGROUND An important question of biological relevance is the polymorphism of the double-helical DNA structure in its free form, and the changes that it undergoes upon protein-binding. We have analysed a database of free DNA crystal structures to assess the inherent variability of the free DNA structure and have compared it with a database of protein-bound DNA crystal structures to ascertain the protein-induced variations. RESULTS Most of the dinucleotide steps in free DNA display high flexibility, assuming different conformations in a sequence-dependent fashion. With the exception of the AA/TT and GA/TC steps, which are 'A-phobic', and the GG/CC step, which is 'A-philic', the dinucleotide steps show no preference for A or B forms of DNA. Protein-bound DNA adopts the B-conformation most often. However, in certain cases, protein-binding causes the DNA backbone to take up energetically unfavourable conformations. At the gross structural level, several protein-bound DNA duplexes are observed to assume a curved conformation in the absence of any large distortions, indicating that a series of normal structural parameters at the dinucleotide and trinucleotide level, similar to the ones in free B-DNA, can give rise to curvature at the overall level. CONCLUSION The results illustrate that the free DNA molecule, even in the crystalline state, samples a large amount of conformational space, encompassing both the A and the B-forms, in the absence of any large ligands. A-form as well as some non-A, non-B, distorted geometries are observed for a small number of dinucleotide steps in DNA structures bound to the proteins belonging to a few specific families. However, for most of the bound DNA structures, across a wide variety of protein families, the average step parameters for various dinucleotide sequences as well as backbone torsion angles are observed to be quite close to the free 'B-like' DNA oligomer values, highlighting the flexibility and biological significance of this structural form.
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Affiliation(s)
- Arvind Marathe
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India.
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Abstract
Profiles provide insights into the lives, backgrounds, career paths, and futures of scientists who serve as Experts on ACS Chemical Biology's online Ask the Expert feature. Ding will begin answering your questions in mid-March, 2009. Readers are encouraged to submit their questions to the Experts at http://community.acs.org/chembiol/ . The editors will post the most interesting exchanges on the web site.
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Kumar TS, Madsen AS, Østergaard ME, Sau SP, Wengel J, Hrdlicka PJ. Functionalized 2'-amino-alpha-L-LNA: directed positioning of intercalators for DNA targeting. J Org Chem 2009; 74:1070-81. [PMID: 19108636 PMCID: PMC2853939 DOI: 10.1021/jo802037v] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Chemically modified oligonucleotides are increasingly applied in nucleic acid based therapeutics and diagnostics. LNA (locked nucleic acid) and its diastereomer alpha-L-LNA are two promising examples thereof that exhibit increased thermal and enzymatic stability. Herein, the synthesis, biophysical characterization, and molecular modeling of N2'-functionalized 2'-amino-alpha-L-LNA is described. Chemoselective N2'-functionalization of protected amino alcohol 1 followed by phosphitylation afforded a structurally varied set of target phosphoramidites, which were incorporated into oligodeoxyribonucleotides. Incorporation of pyrene-functionalized building blocks such as 2'-N-(pyren-1-yl)carbonyl-2'-amino-alpha-L-LNA (monomer X) led to extraordinary increases in thermal affinity of up to +19.5 degrees C per modification against DNA targets in particular. In contrast, incorporation of building blocks with small nonaromatic N2'-functionalities such as 2'-N-acetyl-2'-amino-alpha-L-LNA (monomer V) had detrimental effects on thermal affinity toward DNA/RNA complements with decreases of as much as -16.5 degrees C per modification. Extensive thermal DNA selectivity, favorable entropic contributions upon duplex formation, hybridization-induced bathochromic shifts of pyrene absorption maxima and increases in circular dichroism signal intensity, and molecular modeling studies suggest that pyrene-functionalized 2'-amino-alpha-L-LNA monomers W-Y having short linkers between the bicyclic skeleton and the pyrene moiety allow high-affinity hybridization with DNA complements and precise positioning of intercalators in nucleic acid duplexes. This rigorous positional control has been utilized for the development of probes for emerging therapeutic and diagnostic applications focusing on DNA targeting.
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Affiliation(s)
- T Santhosh Kumar
- Nucleic Acid Center, Department of Physics and Chemistry, University of Southern Denmark, DK-5230 Odense M, Denmark
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Narayana N, Weiss MA. Crystallographic analysis of a sex-specific enhancer element: sequence-dependent DNA structure, hydration, and dynamics. J Mol Biol 2008; 385:469-90. [PMID: 18992257 DOI: 10.1016/j.jmb.2008.10.041] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2008] [Revised: 10/02/2008] [Accepted: 10/06/2008] [Indexed: 11/29/2022]
Abstract
The crystal structure of a sex-specific enhancer element is described at a resolution of 1.6 A. This 16-bp site, designated Dsx(A), functions in the regulation of a genetic switch between male and female patterns of gene expression in Drosophila melanogaster. Related sites are broadly conserved in metazoans, including in the human genome. This enhancer element is unusually rich in general regulatory sequences related to DNA recognition by multiple classes of eukaryotic transcription factors, including the DM motifs, homeodomain, and high mobility group box. Whereas free DNA is often crystallized as an A-form double helix, Dsx(A) was crystallized as B-DNA and thus provides a model for the prebound conformation of diverse regulatory DNA complexes. Sequence-dependent conformational properties that extend features of shorter B-DNA fragments with respect to double helical parameters, groove widths, hydration, and binding of divalent metal ions are observed. The structure also exhibits a sequence-dependent pattern of isotropic thermal B-factors, suggesting possible variation in the local flexibility of the DNA backbone. Such fluctuations are in accord with structural variability observed in prior B-DNA structures. We speculate that sites of intrinsic flexibility within a DNA control element provide hinges for its protein-directed reorganization in a transcriptional preinitiation complex.
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Affiliation(s)
- Narendra Narayana
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106, USA.
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McCann JAB, Berti PJ. Transition-state analysis of the DNA repair enzyme MutY. J Am Chem Soc 2008; 130:5789-97. [PMID: 18393424 DOI: 10.1021/ja711363s] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The transition state (TS) structure of MutY-catalyzed DNA hydrolysis was solved using multiple kinetic isotope effect (KIE) measurements. MutY is a base excision repair enzyme which cleaves adenine from 8-oxo-G:A mismatches in vivo, and also from G:A mismatches in vitro. TS analysis of G:A-DNA hydrolysis revealed a stepwise S(N)1 (D(N)*A(N)(double dagger)) mechanism proceeding through a highly reactive oxacarbenium ion intermediate which would have a lifetime in solution of <10(-10) s. C-N bond cleavage is reversible; the N-glycoside bond breaks and reforms repeatedly before irreversible water attack on the oxacarbenium ion. KIEs demonstrated that MutY uses general acid catalysis by protonating N7. It enforces a 3'-exo sugar ring conformation and other sugar ring distortions to stabilize the oxacarbenium ion. Combining the experimental TS structure with the previously reported crystal structure of an abortive Michaelis complex elucidates the step-by-step catalytic sequence.
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Affiliation(s)
- Joe A B McCann
- Department of Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4M1, Canada
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Solt I, Simon I, Császár AG, Fuxreiter M. Electrostatic versus nonelectrostatic effects in DNA sequence discrimination by divalent ions Mg2+ and Mn2+. J Phys Chem B 2007; 111:6272-9. [PMID: 17497910 DOI: 10.1021/jp0668192] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mg2+ and Mn2+ ions are critical to the functioning of phosphoryl transfer enzymes, such as restriction endonucleases. Although these ions play similar roles in the chemical steps, they govern substrate specificity via modulating sequence discrimination by up to a factor of 10(5) with Mg2+ and only up to a factor of 10 with Mn2+. To explain whether such diversity originates in fundamental differences in the electronic structures of the nucleobase-hydrated-metal ion complexes, structures and interaction energies were determined at the density functional (DFT) and second-order Møller-Plesset (MP2) levels of theory. Although both metal ions favor identical binding sites, Mn2+ complexes exhibit greater distortions from the ideal octahedral geometry and larger variability than the corresponding Mg2+ systems. In inner-shell complexes, with direct contact between the metal and the nucleobase, Mg2+ is preferred over Mn2+ in the gas phase, due primarily to nonelectrostatic effects. The interaction energies of the two metal ions are more similar in the outer-shell complexes, likely due to reduced charge transfer between the hydrated metal ion and the base moieties. Inclusion of solvation effects can amplify the relative nucleobase preferences of Mg2+ and Mn2+, indicating that bulk hydration modulates the balance between electrostatic and nonelectrostatic terms. In most cases, the base substitutions in solution are facilitated more by Mn2+ than by Mg2+. Electrostatic properties of the environment were demonstrated to have a major influence on the nucleobase preferences of the two metal ions. Overall, quantum chemical calculations suggest that the contrasting selectivity of Mg2+ and Mn2+ cofactors toward nucleobases derives from the larger flexibility of the Mn2+ complexes accompanied by the excessive polarization and charge-transfer effects as well as less favorable solvation.
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Affiliation(s)
- Iván Solt
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, H-1518 Budapest PO Box 7, Hungary
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Durbeej B, Eriksson LA. On the Formation of Cyclobutane Pyrimidine Dimers in UV-irradiated DNA: Why are Thymines More Reactive?¶. Photochem Photobiol 2007. [DOI: 10.1562/0031-8655(2003)0780159otfocp2.0.co2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Griffiths KK, Russu IM. Specific Interactions of Divalent Metal Ions with a DNA Duplex Containing the d(CA)n/(GT)nTandem Repeat. J Biomol Struct Dyn 2006; 23:667-76. [PMID: 16615812 DOI: 10.1080/07391102.2006.10507091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Divalent metal ions are essential for maintaining functional states of the DNA molecule. Their participation in DNA structure is modulated by the base sequence and varies depending on the nature of the ion. The present investigation addresses the interaction of Ca2+ ions with a tandem repeat of two CA dinucleotides, (CA)2/(TG)2. The binding of Ca2+ to the repeat is monitored by nuclear magnetic resonance (NMR) spectroscopy using chemical shift mapping. Parallel experiments monitor binding of Mg2+ ions to the repeat as well as binding of each ion to a DNA duplex in which the (CA)2/(TG)2 repeat is eliminated. The results reveal that the direction and the magnitude of chemical shift changes induced by Ca2+ ions in the NMR spectra of the repeat are different from those induced by Mg2+ ions. The differences between the two cations are significantly diminished by the elimination of the (CA)2/(TG)2 repeat. These findings suggest a specific interaction of Ca2+ ions with the (CA)2/(TG)2 motif. The specificity of the interaction resides in the two A-T base pairs of the repeat, and it involves the major groove of the first A-T base pair and both grooves of the second A-T base pair.
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Affiliation(s)
- Keren K Griffiths
- Department of Chemistry and Molecular Biophysics Program, Wesleyan University, Middletown, CT 06459, USA
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Arai S, Chatake T, Ohhara T, Kurihara K, Tanaka I, Suzuki N, Fujimoto Z, Mizuno H, Niimura N. Complicated water orientations in the minor groove of the B-DNA decamer d(CCATTAATGG)2 observed by neutron diffraction measurements. Nucleic Acids Res 2005; 33:3017-24. [PMID: 15914673 PMCID: PMC1140084 DOI: 10.1093/nar/gki616] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
It has long been suspected that the structure and function of a DNA duplex can be strongly dependent on its degree of hydration. By neutron diffraction experiments, we have succeeded in determining most of the hydrogen (H) and deuterium (D) atomic positions in the decameric d(CCATTAATGG)2 duplex. Moreover, the D positions in 27 D2O molecules have been determined. In particular, the complex water network in the minor groove has been observed in detail. By a combined structural analysis using 2.0 Å resolution X-ray and 3.0 Å resolution neutron data, it is clear that the spine of hydration is built up, not only by a simple hexagonal hydration pattern (as reported in earlier X-ray studies), but also by many other water bridges hydrogen-bonded to the DNA strands. The complexity of the hydration pattern in the minor groove is derived from an extraordinary variety of orientations displayed by the water molecules.
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Affiliation(s)
| | | | | | | | | | - Nobuhiro Suzuki
- Department of Biochemistry, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
- Institute of Applied Biochemistry, University of TsukubaTsukuba, Ibaraki 305-8572, Japan
| | - Zui Fujimoto
- Department of Biochemistry, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Hiroshi Mizuno
- Department of Biochemistry, National Institute of Agrobiological Sciences2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
| | - Nobuo Niimura
- To whom correspondence should be addressed. Tel: +81 294 38 5254; Fax: +81 294 38 5272;
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48
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Li X, Eriksson LA. Influence of C5-methylation of cytosine on the formation of cyclobutane pyrimidine dimers. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2004.11.037] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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49
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Hays FA, Jones ZJR, Ho PS. Influence of minor groove substituents on the structure of DNA Holliday junctions. Biochemistry 2004; 43:9813-22. [PMID: 15274635 DOI: 10.1021/bi049461d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The inosine-containing sequence d(CCIGTACm(5)CGG) is shown to crystallize as a four-stranded DNA junction. This structure is nearly identical to the antiparallel junction formed by the parent d(CCGGTACm(5)()CGG) sequence [Vargason, J. M., and Ho, P. S. (2002) J. Biol. Chem. 277, 21041-21049] in terms of its conformational geometry, and inter- and intramolecular interactions within the DNA and between the DNA and solvent, even though the 2-amino group in the minor groove of the important G(3).m(5)C(8) base pair of the junction core trinucleotide (italicized) has been removed. In contrast, the analogous 2,6-diaminopurine sequence d(CCDGTACTGG) crystallizes as resolved duplex DNAs, just like its parent sequence d(CCAGTACTGG) [Hays, F. A., Vargason, J. M., and Ho, P. S. (2003) Biochemistry 42, 9586-9597]. These results demonstrate that it is not the presence or absence of the 2-amino group in the minor groove of the R(3).Y(8) base pair that specifies whether a sequence forms a junction, but the positions of the extracyclic amino and keto groups in the major groove. Finally, the study shows that the arms of the junction can accommodate perturbations to the B-DNA conformation of the stacked duplex arms associated with the loss of the 2-amino substituent, and that two hydrogen bonding interactions from the C(7) and Y(8) pyrimidine nucleotides to phosphate oxygens of the junction crossover specify the geometry of the Holliday junction.
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Affiliation(s)
- Franklin A Hays
- Department of Biochemistry and Biophysics, ALS 2011, Oregon State University, Corvallis, Oregon 97331, USA
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50
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Anthony NG, Johnston BF, Khalaf AI, MacKay SP, Parkinson JA, Suckling CJ, Waigh RD. Short Lexitropsin that Recognizes the DNA Minor Groove at 5‘-ACTAGT-3‘: Understanding the Role of Isopropyl-thiazole. J Am Chem Soc 2004; 126:11338-49. [PMID: 15355117 DOI: 10.1021/ja030658n] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Isopropyl-thiazole ((iPr)Th) represents a new addition to the building blocks of nucleic acid minor groove-binding molecules. The DNA decamer duplex d(CGACTAGTCG)(2) is bound by a short lexitropsin of sequence formyl-PyPy(iPr)Th-Dp (where Py represents N-methyl pyrrole, (iPr)Th represents thiazole with an isopropyl group attached, and Dp represents dimethylaminopropyl). NMR data indicate ligand binding in the minor groove of DNA to the sequence 5'-ACT(5)AG(7)T-3' at a 2:1 ratio of ligand to DNA duplex. Ligand binding, assisted by the enhanced hydrophobicity of the (iPr)Th group, occurs in a head-to-tail fashion, the formyl headgroups being located toward the 5'-ends of the DNA sequence. Sequence reading is augmented through hydrogen bond formation between the exocyclic amine protons of G(7) and the (iPr)Th nitrogen, which lies on the minor groove floor. The B(I)/B(II) DNA backbone equilibrium is altered at the T(5) 3'-phosphate position to accommodate a B(II) configuration. The ligands bind in a staggered mode with respect to one another creating a six base pair DNA reading frame. The introduction of a new DNA sequence-reading element into the recognition jigsaw, combined with an extended reading frame for a small lexitropsin with enhanced hydrophobicity, holds great promise in the development of new, potentially commercially viable drug lead candidates for gene targeting.
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Affiliation(s)
- Nahoum G Anthony
- Department of Pure and Applied Chemistry, 295 Cathedral Street, Glasgow G1 1XL, UK
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