1
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Zubova EA, Strelnikov IA. Experimental detection of conformational transitions between forms of DNA: problems and prospects. Biophys Rev 2023; 15:1053-1078. [PMID: 37974981 PMCID: PMC10643659 DOI: 10.1007/s12551-023-01143-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 09/06/2023] [Indexed: 11/19/2023] Open
Abstract
Under different conditions, the DNA double helix can take different geometric forms. Of the large number of its conformations, in addition to the "canonical" B form, the A, C, and Z forms are widely known, and the D, Hoogsteen, and X forms are less known. DNA locally takes the A, C, and Z forms in the cell, in complexes with proteins. We compare different methods for detecting non-canonical DNA conformations: X-ray, IR, and Raman spectroscopy, linear and circular dichroism in both the infrared and ultraviolet regions, as well as NMR (measurement of chemical shifts and their anisotropy, scalar and residual dipolar couplings and inter-proton distances from NOESY (nuclear Overhauser effect spectroscopy) data). We discuss the difficulties in applying these methods, the problems of theoretical interpretation of the experimental results, and the prospects for reliable identification of non-canonical DNA conformations.
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Affiliation(s)
- Elena A. Zubova
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 4 Kosygin St., Moscow, 119991 Russia
| | - Ivan A. Strelnikov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 4 Kosygin St., Moscow, 119991 Russia
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2
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Biere N, Kreft D, Walhorn V, Schwarzbich S, Glaser T, Anselmetti D. Dinuclear complex-induced DNA melting. J Nanobiotechnology 2023; 21:26. [PMID: 36691056 PMCID: PMC9869567 DOI: 10.1186/s12951-023-01784-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 01/15/2023] [Indexed: 01/24/2023] Open
Abstract
Dinuclear copper complexes have been designed for molecular recognition in order to selectively bind to two neighboring phosphate moieties in the backbone of double strand DNA. Associated biophysical, biochemical and cytotoxic effects on DNA were investigated in previous works, where atomic force microscopy (AFM) in ambient conditions turned out to be a particular valuable asset, since the complexes influence the macromechanical properties and configurations of the strands. To investigate and scrutinize these effects in more depth from a structural point of view, cutting-edge preparation methods and scanning force microscopy under ultra-high vacuum (UHV) conditions were employed to yield submolecular resolution images. DNA strand mechanics and interactions could be resolved on the single base pair level, including the amplified formation of melting bubbles. Even the interaction of singular complex molecules could be observed. To better assess the results, the appearance of treated DNA is also compared to the behavior of untreated DNA in UHV on different substrates. Finally, we present data from a statistical simulation reasoning about the nanomechanics of strand dissociation. This sort of quantitative experimental insights paralleled by statistical simulations impressively shade light on the rationale for strand dissociations of this novel DNA interaction process, that is an important nanomechanistic key and novel approach for the development of new chemotherapeutic agents.
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Affiliation(s)
- Niklas Biere
- grid.7491.b0000 0001 0944 9128Experimental Biophysics & Applied Nanoscience, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
| | - Dennis Kreft
- grid.7491.b0000 0001 0944 9128Experimental Biophysics & Applied Nanoscience, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
| | - Volker Walhorn
- grid.7491.b0000 0001 0944 9128Experimental Biophysics & Applied Nanoscience, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
| | - Sabrina Schwarzbich
- grid.7491.b0000 0001 0944 9128Lehrstuhl für Anorganische Chemie I, Faculty of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Thorsten Glaser
- grid.7491.b0000 0001 0944 9128Lehrstuhl für Anorganische Chemie I, Faculty of Chemistry, Bielefeld University, 33615 Bielefeld, Germany
| | - Dario Anselmetti
- grid.7491.b0000 0001 0944 9128Experimental Biophysics & Applied Nanoscience, Faculty of Physics, Bielefeld University, 33615 Bielefeld, Germany
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3
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The Development of Single Molecule Force Spectroscopy: From Polymer Biophysics to Molecular Machines. Q Rev Biophys 2022; 55:e9. [PMID: 35916314 DOI: 10.1017/s0033583522000087] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4
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Kolenko P, Svoboda J, Černý J, Charnavets T, Schneider B. Structural variability of CG-rich DNA 18-mers accommodating double T-T mismatches. Acta Crystallogr D Struct Biol 2020; 76:1233-1243. [PMID: 33263329 PMCID: PMC7709200 DOI: 10.1107/s2059798320014151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/23/2020] [Indexed: 11/26/2022] Open
Abstract
Solution and crystal data are reported for DNA 18-mers with sequences related to those of bacterial noncoding single-stranded DNA segments called repetitive extragenic palindromes (REPs). Solution CD and melting data showed that the CG-rich, near-palindromic REPs from various bacterial species exhibit dynamic temperature-dependent and concentration-dependent equilibria, including architectures compatible with not only hairpins, which are expected to be biologically relevant, but also antiparallel duplexes and bimolecular tetraplexes. Three 18-mer oligonucleotides named Hpar-18 (PDB entry 6rou), Chom-18 (PDB entry 6ros) and its brominated variant Chom-18Br (PDB entry 6ror) crystallized as isomorphic right-handed A-like duplexes. The low-resolution crystal structures were solved with the help of experimental phases for Chom-18Br. The center of the duplexes is formed by two successive T-T noncanonical base pairs (mismatches). They do not deform the double-helical geometry. The presence of T-T mismatches prompted an analysis of the geometries of these and other noncanonical pairs in other DNA crystals in terms of their fit to the experimental electron densities (RSCC) and their geometric fit to the NtC (dinucleotide conformational) classes (https://dnatco.datmos.org/). Throughout this work, knowledge of the NtC classes was used to refine and validate the crystal structures, and to analyze the mismatches.
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Affiliation(s)
- Petr Kolenko
- Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Brehova 7, 11519 Prague 1, Czech Republic
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Jakub Svoboda
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Jiří Černý
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Tatsiana Charnavets
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
| | - Bohdan Schneider
- Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic
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5
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Vandavasi VG, Blakeley MP, Keen DA, Hu LR, Huang Z, Kovalevsky A. Temperature-Induced Replacement of Phosphate Proton with Metal Ion Captured in Neutron Structures of A-DNA. Structure 2018; 26:1645-1650.e3. [PMID: 30244969 PMCID: PMC6281803 DOI: 10.1016/j.str.2018.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/02/2018] [Accepted: 08/01/2018] [Indexed: 11/18/2022]
Abstract
Nucleic acids can fold into well-defined 3D structures that help determine their function. Knowing precise nucleic acid structures can also be used for the design of nucleic acid-based therapeutics. However, locations of hydrogen atoms, which are key players of nucleic acid function, are normally not determined with X-ray crystallography. Accurate determination of hydrogen atom positions can provide indispensable information on protonation states, hydrogen bonding, and water architecture in nucleic acids. Here, we used neutron crystallography in combination with X-ray diffraction to obtain joint X-ray/neutron structures at both room and cryo temperatures of a self-complementary A-DNA oligonucleotide d[GTGG(CSe)CAC]2 containing 2'-SeCH3 modification on Cyt5 (CSe) at pH 5.6. We directly observed protonation of a backbone phosphate oxygen of Ade7 at room temperature. The proton is replaced with hydrated Mg2+ upon cooling the crystal to 100 K, indicating that metal binding is favored at low temperature, whereas proton binding is dominant at room temperature.
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Affiliation(s)
- Venu Gopal Vandavasi
- Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37922, USA
| | - Matthew P Blakeley
- Large Scale Structures Group, Institut Laue-Langevin, Grenoble 38000, France
| | - David A Keen
- ISIS Facility, Rutherford Appleton Laboratory, Harwell Campus, Didcot OX11 0QX, UK
| | | | - Zhen Huang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37922, USA.
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6
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Šponer J, Bussi G, Krepl M, Banáš P, Bottaro S, Cunha RA, Gil-Ley A, Pinamonti G, Poblete S, Jurečka P, Walter NG, Otyepka M. RNA Structural Dynamics As Captured by Molecular Simulations: A Comprehensive Overview. Chem Rev 2018; 118:4177-4338. [PMID: 29297679 PMCID: PMC5920944 DOI: 10.1021/acs.chemrev.7b00427] [Citation(s) in RCA: 327] [Impact Index Per Article: 54.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Indexed: 12/14/2022]
Abstract
With both catalytic and genetic functions, ribonucleic acid (RNA) is perhaps the most pluripotent chemical species in molecular biology, and its functions are intimately linked to its structure and dynamics. Computer simulations, and in particular atomistic molecular dynamics (MD), allow structural dynamics of biomolecular systems to be investigated with unprecedented temporal and spatial resolution. We here provide a comprehensive overview of the fast-developing field of MD simulations of RNA molecules. We begin with an in-depth, evaluatory coverage of the most fundamental methodological challenges that set the basis for the future development of the field, in particular, the current developments and inherent physical limitations of the atomistic force fields and the recent advances in a broad spectrum of enhanced sampling methods. We also survey the closely related field of coarse-grained modeling of RNA systems. After dealing with the methodological aspects, we provide an exhaustive overview of the available RNA simulation literature, ranging from studies of the smallest RNA oligonucleotides to investigations of the entire ribosome. Our review encompasses tetranucleotides, tetraloops, a number of small RNA motifs, A-helix RNA, kissing-loop complexes, the TAR RNA element, the decoding center and other important regions of the ribosome, as well as assorted others systems. Extended sections are devoted to RNA-ion interactions, ribozymes, riboswitches, and protein/RNA complexes. Our overview is written for as broad of an audience as possible, aiming to provide a much-needed interdisciplinary bridge between computation and experiment, together with a perspective on the future of the field.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences , Kralovopolska 135 , Brno 612 65 , Czech Republic
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Sandro Bottaro
- Structural Biology and NMR Laboratory, Department of Biology , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Richard A Cunha
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Alejandro Gil-Ley
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Giovanni Pinamonti
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Simón Poblete
- Scuola Internazionale Superiore di Studi Avanzati , Via Bonomea 265 , Trieste 34136 , Italy
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science , Palacky University Olomouc , 17. listopadu 12 , Olomouc 771 46 , Czech Republic
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7
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Lubbe AS, Szymanski W, Feringa BL. Recent developments in reversible photoregulation of oligonucleotide structure and function. Chem Soc Rev 2018; 46:1052-1079. [PMID: 28128377 DOI: 10.1039/c6cs00461j] [Citation(s) in RCA: 206] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
There is a growing interest in the photoregulation of biological functions, due to the high level of spatiotemporal precision achievable with light. Additionally, light is non-invasive and waste-free. In particular, the photoregulation of oligonucleotide structure and function is a rapidly developing study field with relevance to biological, physical and material sciences. Molecular photoswitches have been incorporated in oligonucleotides for 20 years, and the field has currently grown beyond fundamental studies on photochemistry of the switches and DNA duplex stability, and is moving towards applications in chemical biology, nanotechnology and material science. Moreover, the currently emerging field of photopharmacology indicates the relevance of photocontrol in future medicine. In recent years, a large number of publications has appeared on photoregulation of DNA and RNA structure and function. New strategies are evaluated and novel, exciting applications are shown. In this comprehensive review, the key strategies for photoswitch inclusion in oligonucleotides are presented and illustrated with recent examples. Additionally the applications that have emerged in recent years are discussed, including gene regulation, drug delivery and materials design. Finally, we identify the challenges that the field currently faces and look forward to future applications.
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Affiliation(s)
- Anouk S Lubbe
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
| | - Wiktor Szymanski
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands. and Department of Radiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, 9713 GZ, Groningen, The Netherlands.
| | - Ben L Feringa
- Centre for Systems Chemistry, Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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8
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5-Formylcytosine does not change the global structure of DNA. Nat Struct Mol Biol 2017; 24:544-552. [PMID: 28504696 DOI: 10.1038/nsmb.3411] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/13/2017] [Indexed: 01/14/2023]
Abstract
The mechanism by which the recently identified DNA modification 5-formylcytosine (fC) is recognized by epigenetic writer and reader proteins is not known. Recently, an unusual DNA structure, F-DNA, has been proposed as the basis for enzyme recognition of clusters of fC. We used NMR and X-ray crystallography to compare several modified DNA duplexes with unmodified analogs and found that in the crystal state the duplexes all belong to the A family, whereas in solution they are all members of the B family. We found that, contrary to previous findings, fC does not significantly affect the structure of DNA, although there are modest local differences at the modification sites. Hence, global conformation changes are unlikely to account for the recognition of this modified base, and our structural data favor a mechanism that operates at base-pair resolution for the recognition of fC by epigenome-modifying enzymes.
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9
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Karthik S, Thirugnanasambandam A, Mandal PK, Gautham N. Crystal structure of d(CCGGGGTACCCCGG) 2 at 1.4 Å resolution. Acta Crystallogr F Struct Biol Commun 2017; 73:259-265. [PMID: 28471357 PMCID: PMC5417315 DOI: 10.1107/s2053230x17004770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/27/2017] [Indexed: 11/10/2022] Open
Abstract
The X-ray crystal structure of the DNA tetradecamer sequence d(CCGGGGTACCCCGG)2 is reported at 1.4 Å resolution in the tetragonal space group P41212. The sequence was designed to fold as a four-way junction. However, it forms an A-type double helix in the presence of barium chloride. The metal ion could not be identified in the electron-density map. The crystallographic asymmetric unit consists of one A-type double helix with 12 base pairs per turn, in contrast to 11 base pairs per turn for canonical A-DNA. A large number of solvent molecules have been identified in both the grooves of the duplex and around the backbone phosphate groups.
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Affiliation(s)
- Selvam Karthik
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | | | - Pradeep Kumar Mandal
- Institut Européen de Chimie et Biologie (IECB), 2 Rue Robert Escarpit, 33607 Pessac CEDEX, France
| | - Namasivayam Gautham
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
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10
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Karthik S, Thirugnanasambandam A, Mandal PK, Gautham N. Comparison of X-ray crystal structures of a tetradecamer sequence d(CCCGGGTACCCGGG) 2 at 1.7 Å resolution. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 36:343-354. [PMID: 28387634 DOI: 10.1080/15257770.2017.1287378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
We present here a comparison of three different X-ray crystal structures of DNA tetradecamer sequence d(CCCGGGTACCCGGG)2 all at about 1.7 Å resolution. The sequence was designed as an attempt to form a DNA four-way junction with A-type helical arms. However, in the presence of zinc, magnesium, and in the absence of any metal ion, it does not take up the junction structure, but forms an A-type double helix. This allowed us to study possible conformational changes in the double helix due to the presence of metal ions. Upon addition of the zinc ion, there is a change in the space group from P41212 to P41. The overall conformation of the duplex remains the same. There are small changes in the interaction of the metal ions with the DNA. In the zinc-bound structure, there are two zinc ions that show direct interaction with the N7 atoms of terminal G13 bases at either end of the molecule. There are small changes in the interhelical contacts. The consequence of these differences is to break some of the symmetry and change the space group.
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Affiliation(s)
- S Karthik
- a CAS in Crystallography and Biophysics , University of Madras , Guindy Campus, Chennai , Tamil Nadu , India
| | - A Thirugnanasambandam
- a CAS in Crystallography and Biophysics , University of Madras , Guindy Campus, Chennai , Tamil Nadu , India
| | - P K Mandal
- a CAS in Crystallography and Biophysics , University of Madras , Guindy Campus, Chennai , Tamil Nadu , India
| | - N Gautham
- a CAS in Crystallography and Biophysics , University of Madras , Guindy Campus, Chennai , Tamil Nadu , India
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11
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Karamychev VN, Panyutin IG, Neumann RD, Zhurkin VB. DNA and RNA folds in transcription complex as evidenced by iodine-125 radioprobing. J Biomol Struct Dyn 2016; 17 Suppl 1:155-67. [PMID: 22607419 DOI: 10.1080/07391102.2000.10506616] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Abstract Folding of the DNA and RNA strands in an arrested T7 RNA polymerase (RNAP) transcription complex was studied by radioprobing, a novel method based on an analysis of the strand breaks produced by decay of the iodine-125 incorporated at the C5 position of cytosine. (125)I-labeled cytosines were incorporated into transcripts at different positions relative to the site of the arrest. The intensities of the DNA breaks inversely correlate with the distances from the (125)I decay site, so the radioprobing data provide information about the spatial RNA/DNA folding during transcription. We found that the yield of DNA strand breaks is significantly higher in the template than the non-template strand. This is consistent with local opening of the DNA duplex and formation of a hybrid between RNA and the template DNA strand. Our data demonstrate that the RNA-DNA hybrid has a nonuni form A-like structure. When the (125)I is incorporatedseven nucleotides from the active center of RNAP, the yield of strand breaks is substantially lower than if (125)I is positioned at the ends of the hybrid. Consequently, the DNA and RNA strands are located closer to each other at the ends of the hybrid and somehow separated in the middle. Surprisingly, the (125)I-induced breaks were detected in both DNA strands upstream from the transcription "bubble" indicating that DNA and RNA are closely associated outside the RNAP cleft. Thus, radioprobing data imply that the RNA/DNA fold in the complex with T7 RNAP is more complicated than had been anticipated by the existing models. Based on the present data, we suggest a sterically feasible model explaining how formation of the long RNA-DNA hybrid can result in the initiation-to-elongation switch in the T7 transcription complex. According to this model, the topological linkage between the DNA and RNA strands provides the necessary stability for the elongation complex, while permitting movement of the polymerase along the DNA duplex.
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Affiliation(s)
- V N Karamychev
- a Department of Nuclear Medicine, Warren G. Magnuson Clinical Center
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12
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Arias-Gonzalez JR. Single-molecule portrait of DNA and RNA double helices. Integr Biol (Camb) 2015; 6:904-25. [PMID: 25174412 DOI: 10.1039/c4ib00163j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The composition and geometry of the genetic information carriers were described as double-stranded right helices sixty years ago. The flexibility of their sugar-phosphate backbones and the chemistry of their nucleotide subunits, which give rise to the RNA and DNA polymers, were soon reported to generate two main structural duplex states with biological relevance: the so-called A and B forms. Double-stranded (ds) RNA adopts the former whereas dsDNA is stable in the latter. The presence of flexural and torsional stresses in combination with environmental conditions in the cell or in the event of specific sequences in the genome can, however, stabilize other conformations. Single-molecule manipulation, besides affording the investigation of the elastic response of these polymers, can test the stability of their structural states and transition models. This approach is uniquely suited to understanding the basic features of protein binding molecules, the dynamics of molecular motors and to shedding more light on the biological relevance of the information blocks of life. Here, we provide a comprehensive single-molecule analysis of DNA and RNA double helices in the context of their structural polymorphism to set a rigorous interpretation of their material response both inside and outside the cell. From early knowledge of static structures to current dynamic investigations, we review their phase transitions and mechanochemical behaviour and harness this fundamental knowledge not only through biological sciences, but also for Nanotechnology and Nanomedicine.
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Affiliation(s)
- J Ricardo Arias-Gonzalez
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia), Calle Faraday no. 9, Cantoblanco, 28049 Madrid, Spain.
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13
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Georgiadis MM, Singh I, Kellett WF, Hoshika S, Benner SA, Richards NGJ. Structural basis for a six nucleotide genetic alphabet. J Am Chem Soc 2015; 137:6947-55. [PMID: 25961938 DOI: 10.1021/jacs.5b03482] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Expanded genetic systems are most likely to work with natural enzymes if the added nucleotides pair with geometries that are similar to those displayed by standard duplex DNA. Here, we present crystal structures of 16-mer duplexes showing this to be the case with two nonstandard nucleobases (Z, 6-amino-5-nitro-2(1H)-pyridone and P, 2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)one) that were designed to form a Z:P pair with a standard "edge on" Watson-Crick geometry, but joined by rearranged hydrogen bond donor and acceptor groups. One duplex, with four Z:P pairs, was crystallized with a reverse transcriptase host and adopts primarily a B-form. Another contained six consecutive Z:P pairs; it crystallized without a host in an A-form. In both structures, Z:P pairs fit canonical nucleobase hydrogen-bonding parameters and known DNA helical forms. Unique features include stacking of the nitro group on Z with the adjacent nucleobase ring in the A-form duplex. In both B- and A-duplexes, major groove widths for the Z:P pairs are approximately 1 Å wider than those of comparable G:C pairs, perhaps to accommodate the large nitro group on Z. Otherwise, ZP-rich DNA had many of the same properties as CG-rich DNA, a conclusion supported by circular dichroism studies in solution. The ability of standard duplexes to accommodate multiple and consecutive Z:P pairs is consistent with the ability of natural polymerases to biosynthesize those pairs. This, in turn, implies that the GACTZP synthetic genetic system can explore the entire expanded sequence space that additional nucleotides create, a major step forward in this area of synthetic biology.
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Bascom G, Andricioaei I. Single-Walled Carbon Nanotubes Modulate the B- to A-DNA Transition. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2014; 118:29441-29447. [PMID: 25553205 PMCID: PMC4275165 DOI: 10.1021/jp5081274] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/20/2014] [Indexed: 06/04/2023]
Abstract
We study the conformational equilibrium between B-to-A forms of ds-DNA adsorbed onto a single-walled carbon nanotube (SWNT) using free energy profile calculations based on all-atom molecular dynamics simulations. The potential of mean force (PMF) of the B-to-A transition of ds-DNA in the presence of an uncharged (10,0) carbon nanotube for two dodecamers with poly-AT or poly-GC sequences is calculated as a function of a root-mean-square-distance (ΔRMSD) difference metric for the B-to-A transition. The calculations reveal that in the presence of a SWNT DNA favors B-form DNA significantly in both poly-GC and poly-AT sequences. Furthermore, the poly-AT DNA:SWNT complex shows a higher energy penalty for adopting an A-like conformation than poly-GC DNA:SWNT by several kcal/mol. The presence of a SWNT on either poly-AT or poly-GC DNA affects the PMF of the transition such that the B form is favored by as much as 10 kcal/mol. In agreement with published data, we find a potential energy minimum between A and B-form DNA at ΔRMSD ≈ -1.5 Å and that the presence of the SWNT moves this minimum by as much as ΔRMSD = 3 Å.
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15
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Kabir A, Kumar GS. Probing the interaction of spermine and 1-naphthyl acetyl spermine with DNA polynucleotides: a comparative biophysical and thermodynamic investigation. MOLECULAR BIOSYSTEMS 2014; 10:1172-83. [PMID: 24643290 DOI: 10.1039/c3mb70616h] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The interaction of spermine and its analogue, 1-naphthyl acetyl spermine with four double stranded DNA polynucleotides has been studied to understand the structural and thermodynamic basis of the binding. The efficacy and specificity of DNA binding of this analogue has not yet been revealed. The energetics of the interaction was studied by isothermal titration calorimetry and differential scanning calorimetry. Circular dichroism spectroscopy, UV-thermal melting and ethidium bromide displacement assay have been employed to characterize the association. Circular dichroism studies showed that 1-naphthyl acetyl spermine caused a stronger structural perturbation in the polynucleotides. Among the adenine-thymine polynucleotides the alternating polynucleotide was more preferred by naphthyl acetyl spermine compared to the preference of spermine for the homo sequence. The higher melting stabilization revealed by the optical melting and differential scanning calorimetry results suggested that the binding of 1-naphthyl acetyl spermine increased the melting temperature and the total standard molar enthalpy of the transition of adenine-thymine polynucleotides. Microcalorimetry results revealed that unlike spermine the binding of 1-naphthyl acetyl spermine was endothermic. The interaction was characterized by total enthalpy-entropy compensation and high standard molar heat capacity values. There are differences in the mode of association of 1-naphthyl acetyl spermine and spermine. 1-naphthyl acetyl spermine binds with an enhanced affinity with the adenine-thymine hetero polynucleotide. Thus, the result suggests the importance of polyamine analogues and their ability to interfere with normal polyamine interactions.
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Affiliation(s)
- Ayesha Kabir
- Biophysical Chemistry Laboratory, Chemistry Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 700 032, India.
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Purushothaman M, Varghese A, Mandal PK, Gautham N. Structure of d(CCCCGGTACCGGGG)2 at 1.65 Å resolution. Acta Crystallogr F Struct Biol Commun 2014; 70:860-5. [PMID: 25005078 PMCID: PMC4089521 DOI: 10.1107/s2053230x1401084x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 05/12/2014] [Indexed: 11/10/2022] Open
Abstract
The crystal structure of the tetradecanucleotide d(CCCCGGTACCGGGG)2 has previously been reported as an A-type double helix at a resolution of 2.5 Å in space group P41. Here, the structure of this sequence was determined at a significantly higher resolution of 1.65 Å in space group P4₁2₁2. The differences in crystal packing between the former and latter are described. The crystallographic asymmetric unit consists of one tetradecanucleotide duplex that spans more than one full turn of the A-helix. This structure allowed the unambiguous identification of solvent interactions.
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Affiliation(s)
- Monica Purushothaman
- CAS in Crystallography and Biophysics, University of Madras, Guindy, Chennai, Tamil Nadu 600 025, India
| | - Anna Varghese
- CAS in Crystallography and Biophysics, University of Madras, Guindy, Chennai, Tamil Nadu 600 025, India
| | - Pradeep Kumar Mandal
- Institut Européen de Chimie et Biologie (IECB), 2 Rue Robert Escarpit, 33607 Pessac CEDEX, France
| | - Namasivayam Gautham
- CAS in Crystallography and Biophysics, University of Madras, Guindy, Chennai, Tamil Nadu 600 025, India
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17
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Keniry MA, Owen EA. Insight into the molecular recognition of spermine by DNA quadruplexes from an NMR study of the association of spermine with the thrombin-binding aptamer. J Mol Recognit 2013; 26:308-17. [PMID: 23657986 DOI: 10.1002/jmr.2274] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/22/2013] [Accepted: 02/23/2013] [Indexed: 01/22/2023]
Abstract
The preferred residence sites and the conformation of DNA-bound polyamines are central to understanding the regulatory roles of polyamines. To this end, we have used a series of selective (13)C-edited and selective total correlation spectroscopy-edited one-dimensional (1D) nuclear Overhauser effect spectroscopy NMR experiments to determine a number of intramolecular (1)H nuclear Overhauser effect (NOE) connectivities in (13)C-labelled spermine bound to the thrombin-binding aptamer. The results provide evidence that the aptamer-bound spermine adopts a conformation that optimizes electrostatic and hydrogen bond contacts with the aptamer backbone. The distance between the nitrogen atoms of the central aminobutyl is reduced by an increase in the population of gauche conformers at the C6-C7 bonds, which results in either a curved or S-shaped spermine conformation. Molecular modelling contributes insight toward the mode of spermine binding of these spermine structures within the narrow grooves of DNA quadruplexes. In each case, the N5 ammonium group makes hydrogen bonds with two nearby phosphates across the narrow groove. Our results have implications for the understanding of chromatin structure and the rational design of quadruplex-binding drugs.
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Affiliation(s)
- Max A Keniry
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia.
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Wysoczynski CL, Roemer SC, Dostal V, Barkley RM, Churchill MEA, Malarkey CS. Reversed-phase ion-pair liquid chromatography method for purification of duplex DNA with single base pair resolution. Nucleic Acids Res 2013; 41:e194. [PMID: 24013567 PMCID: PMC3814375 DOI: 10.1093/nar/gkt815] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Obtaining quantities of highly pure duplex DNA is a bottleneck in the biophysical analysis of protein–DNA complexes. In traditional DNA purification methods, the individual cognate DNA strands are purified separately before annealing to form DNA duplexes. This approach works well for palindromic sequences, in which top and bottom strands are identical and duplex formation is typically complete. However, in cases where the DNA is non-palindromic, excess of single-stranded DNA must be removed through additional purification steps to prevent it from interfering in further experiments. Here we describe and apply a novel reversed-phase ion-pair liquid chromatography purification method for double-stranded DNA ranging in lengths from 17 to 51 bp. Both palindromic and non-palindromic DNA can be readily purified. This method has the unique ability to separate blunt double-stranded DNA from pre-attenuated (n-1, n-2, etc) synthesis products, and from DNA duplexes with single base pair overhangs. Additionally, palindromic DNA sequences with only minor differences in the central spacer sequence of the DNA can be separated, and the purified DNA is suitable for co-crystallization of protein–DNA complexes. Thus, double-stranded ion-pair liquid chromatography is a useful approach for duplex DNA purification for many applications.
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Affiliation(s)
- Christina L Wysoczynski
- Department of Pharmacology, University of Colorado Denver, School of Medicine, Aurora, CO 80045, USA and Program in Structural Biology and Biochemistry, University of Colorado Denver, School of Medicine, Aurora, CO 80045, USA
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Kabir A, Suresh Kumar G. Binding of the biogenic polyamines to deoxyribonucleic acids of varying base composition: base specificity and the associated energetics of the interaction. PLoS One 2013; 8:e70510. [PMID: 23894663 PMCID: PMC3722294 DOI: 10.1371/journal.pone.0070510] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 06/24/2013] [Indexed: 11/18/2022] Open
Abstract
Background The thermodynamics of the base pair specificity of the binding of the polyamines spermine, spermidine, putrescine, and cadaverine with three genomic DNAs Clostridium perfringens, 27% GC, Escherichia coli, 50% GC and Micrococcus lysodeikticus, 72% GC have been studied using titration calorimetry and the data supplemented with melting studies, ethidium displacement and circular dichroism spectroscopy results. Methodology/Principal Findings Isothermal titration calorimetry, differential scanning calorimetry, optical melting studies, ethidium displacement, circular dichroism spectroscopy are the various techniques employed to characterize the interaction of four polyamines, spermine, spermidine, putersine and cadaverine with the DNAs. Polyamines bound stronger with AT rich DNA compared to the GC rich DNA and the binding varied depending on the charge on the polyamine as spermine>spermidine >putrescine>cadaverine. Thermodynamics of the interaction revealed that the binding was entropy driven with small enthalpy contribution. The binding was influenced by salt concentration suggesting the contribution from electrostatic forces to the Gibbs energy of binding to be the dominant contributor. Each system studied exhibited enthalpy-entropy compensation. The negative heat capacity changes suggested a role for hydrophobic interactions which may arise due to the non polar interactions between DNA and polyamines. Conclusion/Significance From a thermodynamic analysis, the AT base specificity of polyamines to DNAs has been elucidated for the first time and supplemented by structural studies.
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Affiliation(s)
- Ayesha Kabir
- Biophysical Chemistry Laboratory, Chemistry Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Gopinatha Suresh Kumar
- Biophysical Chemistry Laboratory, Chemistry Division, CSIR-Indian Institute of Chemical Biology, Kolkata, India
- * E-mail:
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Beššeová I, Banáš P, Kührová P, Košinová P, Otyepka M, Šponer J. Simulations of A-RNA Duplexes. The Effect of Sequence, Solute Force Field, Water Model, and Salt Concentration. J Phys Chem B 2012; 116:9899-916. [DOI: 10.1021/jp3014817] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Ivana Beššeová
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
| | - Pavel Banáš
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
- 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
| | - Petra Kührová
- 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
| | - Pavlína Košinová
- 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
| | - Michal Otyepka
- Institute
of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska
135, 612 65 Brno, Czech Republic
- 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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Venkadesh S, Mandal PK, Gautham N. Crystallographic and spectroscopic studies of d(CCGGTACCGG). NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2012; 31:184-96. [PMID: 22356234 DOI: 10.1080/15257770.2011.648363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The decanucleotide sequence d(CCGGTACCGG) crystallizes as a four-way junction at low cobalt ion concentrations (i.e., 1 mM). When the cobalt concentration in the crystallization solution is increased to 5 mM, the sequence crystallizes as resolved B-DNA duplexes. Gel retardation studies of the decamer show both a faint slow-moving band and a much thicker fast-moving band at low cobalt ion concentrations, and only the intense fast-moving band at higher ion concentration. Circular dichroism (CD) spectroscopy of the decamer indicates a structural transition as the cobalt ion concentration in the solution is increased, probably from B-type to A-type DNA. These studies revealed that the oligomer sequence has several conformations and structures accessible to it, in a manner dependent on sequence, ion concentration, and DNA concentration. [Supplementary materials are available for this article. Go to the publisher's online edition of Nucleosides, Nucleotides & Nucleic Acids for the following free supplemental resources(s): Supplementary Figures 1, 2, and 3.].
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Affiliation(s)
- S Venkadesh
- CAS in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai, India
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22
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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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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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FAN WENJIE, ZHANG RUIQIN. COMPUTATION OF LARGE SYSTEMS WITH AN ECONOMIC BASIS SET: AB INITIO CALCULATIONS OF BIOLOGICAL NUCLEIC ACID BASE PAIRS. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633606002350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We show that an economic basis set, in which the polarization functions are considered only for oxygen and nitrogen atoms of strong electronegativity, can be used to determine reliable structures of nucleic acid base pairs. Mulliken charge analysis and the HOMO-LUMO gap in single-point energy calculations using standard basis sets on the geometric structures optimized with the economic basis set found reasonable agreements with the ones of standard calculations. This study is expected to provide a general guideline for basis set selection in the computation of large biological systems being performed with considerable high accuracy, using a low cost computation resource.
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Affiliation(s)
- WENJIE FAN
- Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, P. R. China
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, P. R. China
| | - RUIQIN ZHANG
- Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong, Hong Kong SAR, P. R. China
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, P. R. China
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Hormeño S, Ibarra B, Valpuesta JM, Carrascosa JL, Ricardo Arias-Gonzalez J. Mechanical stability of low-humidity single DNA molecules. Biopolymers 2011; 97:199-208. [DOI: 10.1002/bip.21728] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 10/14/2011] [Indexed: 12/12/2022]
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Venkadesh S, Mandal PK, Gautham N. The structure of a full turn of an A-DNA duplex d(CGCGGGTACCCGCG)₂. Biochem Biophys Res Commun 2011; 407:307-12. [PMID: 21397589 DOI: 10.1016/j.bbrc.2011.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Accepted: 03/02/2011] [Indexed: 11/25/2022]
Abstract
We report the 2.6Å resolution crystal structure of the tetra-decamer d(CGCGGGTACCCGCG) in the tetragonal space group P4₃. This sequence contains the KpnI restriction site GGTACC in the centre which is flanked by alternating 'CG' sequences, and has a 'TA' step at the centre. These are features could favour the left-handed Z type helix. Despite this, overall the molecule has the A form. This is the first tetra-decamer crystallized in the A-DNA conformation, i.e. more than one full turn of the A helix. The crystallographic asymmetric unit consists of one tetra-decamer duplex. The helical twist and slide, as well as the base pair-base pair stacking interactions show alternations at the alternating pyrimidine-purine and purine-pyrimidine base steps. This variation is reminiscent of the dinucleotide repeat in left-handed Z-DNA helices. The crystal packing is unlike other A-DNA crystal structures, with each helix having a large number of contacts of many different types with symmetry-related neighbours.
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Affiliation(s)
- S Venkadesh
- CAS in Crystallography and Biophysics, University of Madras, Chennai 600 025, Tamil Nadu, India
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28
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Chattopadhyay B, Mukherjee M. Molecular dynamics study and electronic structure evolution of a DNA duplex d(CCCGATCGGG)2. J Phys Chem B 2011; 115:1760-6. [PMID: 21291265 DOI: 10.1021/jp109779v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The molecular dynamics simulations and electronic structure evolution of a A-DNA decamer, d(CCCGATCGGG)(2), in the presence and absence of [Co(NH(3))(6)](3+) ions have been investigated. In both cases, the results of 2.5 ns MD simulation indicate a A-DNA→B-DNA transition. Ab initio DFT calculations were performed on a series of conformations representing the A→B transitions to reveal the dynamical behavior of the electronic structure of the decamer. The results suggest that the conformational parameters as well as the surrounding environment have no direct correlation with the electronic structures. Instead, the thermal fluctuations play an important role in the electronic structure of the present DNA system.
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Affiliation(s)
- Basab Chattopadhyay
- Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata 700032, India
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29
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Boryskina OP, Tkachenko MY, Shestopalova AV. Protein-DNA complexes: specificity and DNA readout mechanisms. ACTA ACUST UNITED AC 2011. [DOI: 10.7124/bc.00007c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- O. P. Boryskina
- O. Ya. Usikov Institute for Radio Physics and Electronics, National Academy of Sciences of Ukraine
| | - M. Yu. Tkachenko
- O. Ya. Usikov Institute for Radio Physics and Electronics, National Academy of Sciences of Ukraine
| | - A. V. Shestopalova
- O. Ya. Usikov Institute for Radio Physics and Electronics, National Academy of Sciences of Ukraine
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Singh A, Snyder S, Lee L, Johnston APR, Caruso F, Yingling YG. Effect of oligonucleotide length on the assembly of DNA materials: molecular dynamics simulations of layer-by-layer DNA films. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:17339-17347. [PMID: 20939494 DOI: 10.1021/la102762t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
DNA strand length has been found to be an important factor in many DNA-based nanoscale systems. Here, we apply molecular dynamics simulations in a synergistic effort with layer-by-layer experimental data to understand the effect of DNA strand length on the assembly of DNA films. The results indicate that short (less than 10 bases) and long (more than 30 bases) single-stranded DNAs do not exhibit optimal film growth, and this can be associated with the limited accessibility of the bases on the surface due to formation of self-protected interactions that prevent efficient hybridization. Interestingly, the presence of a duplex attached to a single strand significantly alters the persistence length of the polyT strands. Our study suggests that restrained polyT, compared to labile suspensions of free polyT, are more capable of hybridization and hence DNA-based assembly.
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Affiliation(s)
- Abhishek Singh
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
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31
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Secco F, Venturini M, Biver T, Sánchez F, Prado-Gotor R, Grueso E. Solvent Effects on the Kinetics of the Interaction of 1-Pyrenecarboxaldehyde with Calf Thymus DNA. J Phys Chem B 2010; 114:4686-91. [DOI: 10.1021/jp910411c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fernando Secco
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy, and Department of Physical Chemistry, University of Seville, C/Profesor García González s/n, 41012, Seville, Spain
| | - Marcella Venturini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy, and Department of Physical Chemistry, University of Seville, C/Profesor García González s/n, 41012, Seville, Spain
| | - Tarita Biver
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy, and Department of Physical Chemistry, University of Seville, C/Profesor García González s/n, 41012, Seville, Spain
| | - Francisco Sánchez
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy, and Department of Physical Chemistry, University of Seville, C/Profesor García González s/n, 41012, Seville, Spain
| | - Rafael Prado-Gotor
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy, and Department of Physical Chemistry, University of Seville, C/Profesor García González s/n, 41012, Seville, Spain
| | - Elia Grueso
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento, 35, 56126 Pisa, Italy, and Department of Physical Chemistry, University of Seville, C/Profesor García González s/n, 41012, Seville, Spain
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32
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Vokáčová Z, Bickelhaupt FM, Šponer J, Sychrovský V. Structural Interpretation of J Coupling Constants in Guanosine and Deoxyguanosine: Modeling the Effects of Sugar Pucker, Backbone Conformation, and Base Pairing. J Phys Chem A 2009; 113:8379-86. [DOI: 10.1021/jp902473v] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Zuzana Vokáčová
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo Square 2, 166 10 Prague 6, Czech Republic, Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Scheikundig Laboratorium der Vrije Universiteit, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
| | - F. Matthias Bickelhaupt
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo Square 2, 166 10 Prague 6, Czech Republic, Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Scheikundig Laboratorium der Vrije Universiteit, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
| | - JiYí Šponer
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo Square 2, 166 10 Prague 6, Czech Republic, Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Scheikundig Laboratorium der Vrije Universiteit, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
| | - Vladimír Sychrovský
- Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Flemingovo Square 2, 166 10 Prague 6, Czech Republic, Theoretical Chemistry and Amsterdam Center for Multiscale Modeling, Scheikundig Laboratorium der Vrije Universiteit, De Boelelaan 1083, NL-1081 HV Amsterdam, The Netherlands, and Institute of Biophysics, v.v.i., Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
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Morgado CA, Jurečka P, Svozil D, Hobza P, Šponer J. Balance of Attraction and Repulsion in Nucleic-Acid Base Stacking: CCSD(T)/Complete-Basis-Set-Limit Calculations on Uracil Dimer and a Comparison with the Force-Field Description. J Chem Theory Comput 2009; 5:1524-44. [DOI: 10.1021/ct9000125] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Claudio A. Morgado
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic
| | - Petr Jurečka
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic
| | - Daniel Svozil
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic
| | - Pavel Hobza
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo náměstí 2, 166 10 Prague 6, Czech Republic, and Department of Physical Chemistry, Palacky University, tr. Svobody 26, 771 46, Olomouc, Czech Republic
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Abstract
One obstacle to achieving complete understanding of the principles underlying sequence-dependent recognition of DNA is the paucity of structural data for DNA recognition sequences in their free (unbound) state. Here, we carried out crystallization screening of 50 DNA duplexes containing cognate protein binding sites and obtained new crystal structures of free DNA binding sites for three distinct modes of DNA recognition: anti-parallel beta strands (MetR), helix-turn-helix motif + hinge helices (PurR), and zinc fingers (Zif268). Structural changes between free and protein-bound DNA are manifested differently in each case. The new DNA structures reveal that distinctive sequence-dependent DNA geometry dominates recognition by MetR, protein-induced bending of DNA dictates recognition by PurR, and deformability of DNA along the A-B continuum is important in recognition by Zif268. Together, our findings show that crystal structures of free DNA binding sites provide new information about the nature of protein-DNA interactions and thus lend insights towards a structural code for DNA recognition.
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35
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Beššeová I, Otyepka M, Réblová K, Šponer J. Dependence of A-RNA simulations on the choice of the force field and salt strength. Phys Chem Chem Phys 2009; 11:10701-11. [DOI: 10.1039/b911169g] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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36
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Tsai AG, Engelhart AE, Hatmal MM, Houston SI, Hud NV, Haworth IS, Lieber MR. Conformational variants of duplex DNA correlated with cytosine-rich chromosomal fragile sites. J Biol Chem 2008; 284:7157-64. [PMID: 19106104 DOI: 10.1074/jbc.m806866200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We found that several major chromosomal fragile sites in human lymphomas, including the bcl-2 major breakpoint region, bcl-1 major translocation cluster, and c-Myc exon 1-intron 1 boundary, contain distinctive sequences of consecutive cytosines exhibiting a high degree of reactivity with the structure-specific chemical probe bisulfite. To assess the inherent structural variability of duplex DNA in these regions and to determine the range of structures reactive to bisulfite, we have performed bisulfite probing on genomic DNA in vitro and in situ; on duplex DNA in supercoiled and linearized plasmids; and on oligonucleotide DNA/DNA and DNA/2'-O-methyl RNA duplexes. Bisulfite is significantly more reactive at the frayed ends of DNA duplexes, which is expected given that bisulfite is an established probe of single-stranded DNA. We observed that bisulfite also distinguishes between more subtle sequence/structural differences in duplex DNA. Supercoiled plasmids are more reactive than linear DNA; and sequences containing consecutive cytosines, namely GGGCCC, are more reactive than those with alternating guanine and cytosine, namely GCGCGC. Circular dichroism and x-ray crystallography show that the GGGCCC sequence forms an intermediate B/A structure. Molecular dynamics simulations also predict an intermediate B/A structure for this sequence, and probe calculations suggest greater bisulfite accessibility of cytosine bases in the intermediate B/A structure over canonical B- or A-form DNA. Electrostatic calculations reveal that consecutive cytosine bases create electropositive patches in the major groove, predicting enhanced localization of the bisulfite anion at homo-C tracts over alternating G/C sequences. These characteristics of homo-C tracts in duplex DNA may be associated with DNA-protein interactions in vivo that predispose certain genomic regions to chromosomal fragility.
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Affiliation(s)
- Albert G Tsai
- Department of Biochemistry, University of Southern California Norris Comprehensive Cancer Center, Los Angeles, California 90089-9176, USA
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37
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Kumar A, Sevilla MD, Suhai S. Microhydration of the guanine-cytosine (GC) base pair in the neutral and anionic radical states: a density functional study. J Phys Chem B 2008; 112:5189-98. [PMID: 18380501 DOI: 10.1021/jp710957p] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A density functional study of the effects of microhydration on the guanine-cytosine (GC) base pair and its anion radical is presented. Geometries of the GC base pair in the presence of 6 and 11 water molecules were fully optimized in the neutral (GC-nH2O) and anion radical [(GC-nH2O)*-] (n = 6 and 11) states using the B3LYP method and the 6-31+G** basis set. Further, vibrational frequency analysis at the same level of theory (B3LYP/6-31+G**) was also performed to ensure the existence of local minima in these hydrated structures. It was found that water molecules surrounding the GC base pair have significant effects on the geometry of the GC base pair and promote nonplanarity in the GC base pair. The calculated structures were found to be in good agreement with those observed experimentally and obtained in molecular dynamics (MD) simulation studies. The water molecules in neutral GC-nH2O complexes lie near the ring plane of the GC base pair where they undergo hydrogen bonding with both GC and each other. However, in the GC anion radical complexes (GC-nH2O, n = 6, 11), the water molecules are displaced substantially from the GC ring plane. For GC-11H2O*-, a water molecule is hydrogen-bonded with the C6 atom of the cytosine base. We found that the hydration shell initially destabilizes the GC base pair toward electron capture as a transient anion. Energetically unstable diffuse states in the hydration shell are suggested to provide an intermediate state for the excess electron before molecular reorganization of the water molecules and the base pair results in a stable anion formation. The singly occupied molecular orbital (SOMO) in the anion radical complexes clearly shows that an excess electron localizes into a pi orbital of cytosine. The zero-point-energy (ZPE-) corrected adiabatic electron affinities (AEAs) of the GC-6H2O and GC-11H2O complexes, at the B3LYP/6-31+G** level of theory, were found to be 0.74 and 0.95 eV, respectively. However, the incorporation of bulk water as a solvent using the polarized continuum model (PCM) increases the EAs of these complexes to 1.77 eV.
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Affiliation(s)
- Anil Kumar
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA
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38
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Fan WJ, Zhang RQ, Liu S. Computation of large systems with an economic basis set: Structures and reactivity indices of nucleic acid base pairs from density functional theory. J Comput Chem 2007; 28:967-74. [PMID: 17269120 DOI: 10.1002/jcc.20670] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We show here that an economic basis set can describe nucleic acid base pairs involving the hydrogen bond interactions in density functional calculations. The economic basis set in which the polarization function is added only to oxygen and nitrogen atoms of strong electronegativity can predict reliable geometric structures and dipole moment of nucleic acid base pairs, comparable to those obtained from the basis set of 6-31G* in B3LYP calculations. Combining single point calculations with the standard basis set on the geometric structures optimized by the economic basis set, the present approach has predicted accurate natural bond orbital charge, binding energy, electronegativity, hardness, softness, and electrophilicity index. The principle for basis selection presented in this study can be regarded as a general guideline in the computation of large biological systems with considerably high accuracy and low computational expense.
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Affiliation(s)
- W J Fan
- Center of Super-Diamond and Advanced Films (COSDAF) & Department of Physics and Materials Science, City University of Hong Kong, Hong Kong SAR, People's Republic of China
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39
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Manku S, Hall DG. Screening of a combinatorial library of synthetic polyamines displaying selectivity in multiple ion-pairing interactions with model polyanionic compounds in aqueous organic solutions. ACTA ACUST UNITED AC 2006; 8:551-61. [PMID: 16827568 DOI: 10.1021/cc0501559] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The biological activity of natural polyamines is due in large part to their ability to form ion-pairing interactions with polyanionic biomolecules, such as proteins, oligonucleotides, and sulfated oligosaccharides. Unfortunately, the diversity of biogenic polyamines is compromised by their limitation to only just a few internitrogen spacers. As a proof-of-principle study, a synthetic split-pool library of linear triamines was screened in an on-bead assay against a selection of model trisulfonated azo dyes (1, 2, and 3) and a short glutamate-rich nonameric peptide (4) to demonstrate its use in the discovery of selective ligands via multivalent ion pairing. From screening a 196-membered split-pool library against the dyes in aqueous organic solutions, with or without spermidine as competing ligand, it was found that the most frequent residues possessed internitrogen distances that were very similar to the sulfonate distances on the dyes. The results from these screening assays were used in the design of two polyamine sequences (8, 8Aoc(R)-8Aoc(R), and 12, 2Acc(R)-epsilonAhx(R)) for follow-up studies in solution phase. These triamines demonstrated the same selectively toward dyes 2 and 3 as observed by the solid-phase approach. In addition, resin-supported triamines, synthesized as discrete compounds, were able to selectively extract either dye 2 or 3 from a mixture of the two, further verifying the observations made from the library screening efforts. With peptide 4, containing three glutamate residues, a preference was found for rather long residues (12 and 8 carbons long), which is suggestive of a linear peptide, rather than a helical motif under the conditions of the screening.
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Affiliation(s)
- Sukhdev Manku
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2
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40
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Jana B, Pal S, Maiti PK, Lin ST, Hynes JT, Bagchi B. Entropy of Water in the Hydration Layer of Major and Minor Grooves of DNA. J Phys Chem B 2006; 110:19611-8. [PMID: 17004828 DOI: 10.1021/jp061588k] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Transport properties (translational and rotational) of water in the two grooves of the B-DNA duplex are known to be different from those in the bulk. Here, we use a recently developed theoretical scheme to compute the entropies of water molecules in both of the grooves of DNA and compare them with that in the bulk. The scheme requires as input both translational and rotational velocity autocorrelation function (C(V)(t) and C(omega)(t), respectively) data. These velocity autocorrelation functions were computed from an atomistic MD simulation of a B-DNA duplex (36 base pairs long) in explicit water (TIP3P). The average values of the entropy of water at 300 K in both of the grooves of DNA (the TS value in the major groove is 6.71 kcal/mol and that in the minor groove is 6.41 kcal/mol) are found to be significantly lower than that in bulk water (the TS value is 7.27 kcal/mol). Thus, the entropic contribution to the free energy change (TDeltaS) of transferring a minor groove water molecule to the bulk is 0.86 kcal/mol and of transferring a major groove water to the bulk is 0.56 kcal/mol at 300 K, which is to be compared with 1.44 kcal/mol for melting of ice at 273 K. We also calculate the energy of interaction of each water molecule with the rest of the atoms in the system and hence calculate the chemical potential (Helmholtz free energy per water molecule, A = E - TS) in the different domains. The identical free energy value of water molecules in the different domains proves the robustness of the scheme. We propose that the configurational entropy of water in the grooves can be used as a measure of the mobility (or microviscosity) of water molecules in a given domain.
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Affiliation(s)
- Biman Jana
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore-560012, India
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41
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Réblová K, Lankas F, Rázga F, Krasovska MV, Koca J, Sponer J. Structure, dynamics, and elasticity of free 16s rRNA helix 44 studied by molecular dynamics simulations. Biopolymers 2006; 82:504-20. [PMID: 16538608 DOI: 10.1002/bip.20503] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molecular dynamics (MD) simulations were employed to investigate the structure, dynamics, and local base-pair step deformability of the free 16S ribosomal helix 44 from Thermus thermophilus and of a canonical A-RNA double helix. While helix 44 is bent in the crystal structure of the small ribosomal subunit, the simulated helix 44 is intrinsically straight. It shows, however, substantial instantaneous bends that are isotropic. The spontaneous motions seen in simulations achieve large degrees of bending seen in the X-ray structure and would be entirely sufficient to allow the dynamics of the upper part of helix 44 evidenced by cryo-electron microscopic studies. Analysis of local base-pair step deformability reveals a patch of flexible steps in the upper part of helix 44 and in the area proximal to the bulge bases, suggesting that the upper part of helix 44 has enhanced flexibility. The simulations identify two conformational substates of the second bulge area (bottom part of the helix) with distinct base pairing. In agreement with nuclear magnetic resonance (NMR) and X-ray studies, a flipped out conformational substate of conserved 1492A is seen in the first bulge area. Molecular dynamics (MD) simulations reveal a number of reversible alpha-gamma backbone flips that correspond to transitions between two known A-RNA backbone families. The flipped substates do not cumulate along the trajectory and lead to a modest transient reduction of helical twist with no significant influence on the overall geometry of the duplexes. Despite their considerable flexibility, the simulated structures are very stable with no indication of substantial force field inaccuracies.
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Affiliation(s)
- Kamila Réblová
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 61265 Brno, Czech Republic
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42
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Gore J, Bryant Z, Nöllmann M, Le MU, Cozzarelli NR, Bustamante C. DNA overwinds when stretched. Nature 2006; 442:836-9. [PMID: 16862122 DOI: 10.1038/nature04974] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 06/08/2006] [Indexed: 11/08/2022]
Abstract
DNA is often modelled as an isotropic rod, but its chiral structure suggests the possible importance of anisotropic mechanical properties, including coupling between twisting and stretching degrees of freedom. Simple physical intuition predicts that DNA should unwind under tension, as it is pulled towards a denatured structure. We used rotor bead tracking to directly measure twist-stretch coupling in single DNA molecules. Here we show that for small distortions, contrary to intuition, DNA overwinds under tension, reaching a maximum twist at a tension of approximately 30 pN. As tension is increased above this critical value, the DNA begins to unwind. The observed twist-stretch coupling predicts that DNA should also lengthen when overwound under constant tension, an effect that we quantitatively confirm. We present a simple model that explains these unusual mechanical properties, and also suggests a possible origin for the anomalously large torsional rigidity of DNA. Our results have implications for the action of DNA-binding proteins that must stretch and twist DNA to compensate for variability in the lengths of their binding sites. The requisite coupled DNA distortions are favoured by the intrinsic mechanical properties of the double helix reported here.
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Affiliation(s)
- Jeff Gore
- Department of Physics, University of California, Berkeley, California 94720, USA
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43
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Kumar A, Mishra PC, Suhai S. Binding of Gold Clusters with DNA Base Pairs: A Density Functional Study of Neutral and Anionic GC−Aun and AT−Aun (n = 4, 8) Complexes. J Phys Chem A 2006; 110:7719-27. [PMID: 16774220 DOI: 10.1021/jp060932a] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binding of clusters of gold atoms (Au) with the guanine-cytosine (GC) and adenine-thymine (AT) Watson-Crick DNA base pairs was studied using the density functional theory (DFT). Geometries of the neutral GC-Au(n) and AT-Au(n) and the corresponding anionic (GC-Au(n))(-1) and (AT-Au(n))(-1) (n = 4, 8) complexes were fully optimized in different electronic states, that is, singlet and triplet states for the neutral complexes and doublet and quartet states for the anionic complexes, using the B3LYP density functional method. The 6-31+G basis set was used for all atoms except gold. For gold atoms, the Los Alamos effective core potential (ECP) basis set LanL2DZ was employed. Vibrational frequency calculations were performed to ensure that the optimized structures corresponded to potential energy surface minima. The gold clusters around the neutral GC and AT base pairs have a T-shaped structure, which satisfactorily resemble those observed experimentally and in other theoretical studies. However, in anionic GC and AT base pairs, the gold clusters have extended zigzag and T-shaped structures. We found that guanine and adenine have high affinity for Au clusters, with their N3 and N7 sites being preferentially involved in binding with the same. The calculated adiabatic electron affinities (AEAs) of the GC-Au(n)complexes (n = 4, 8) were found to be much larger than those of the isolated base pairs.
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Affiliation(s)
- Anil Kumar
- Department of Physics, Banaras Hindu University, Varanasi-221 005, India
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44
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Dohm JA, Hsu MH, Hwu JR, Huang RCC, Moudrianakis EN, Lattman EE, Gittis AG. Influence of Ions, Hydration, and the Transcriptional Inhibitor P4N on the Conformations of the Sp1 Binding Site. J Mol Biol 2005; 349:731-44. [PMID: 15896803 DOI: 10.1016/j.jmb.2005.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Revised: 03/30/2005] [Accepted: 04/01/2005] [Indexed: 11/19/2022]
Abstract
Three crystal structures containing the entire Sp1 consensus sequence d(GGGGCGGGG) with two or three additional base-pairs on either the 5' or 3' ends and overhangs have been determined. Despite the different lengths of DNA in the pseudo-dodecamers and pseudo-tridecamer, all three structures form A-DNA duplexes that share a common set of crystal contacts, including a T*(G.C) base triplet and a 5'-overhang that flips out and away from the helical axes to form a Hoogsteen base-pair with the 3'-overhang of a symmetry mate. The global conformations of the three structures differ, however, in the widths of their respective major grooves, the lengths of the molecules, and the extent of crystal packing. The structures were determined from crystals grown in an unusual precipitant for A-DNA, polyethylene glycol (PEG) 400, in combination with polyamines or ions; cobalt hexamine for the pseudo-tridecamer, and spermidine for the pseudo-dodecamers. As the Sp1 binding site is a target for antiviral and anticancer drugs, pseudo-dodecamer crystals were soaked with one such antiviral and anticancer compound, P4N. Although P4N was not visualized unambiguously in the electron density maps, the effect of the drug is evident from significant differences in the lattice constants, crystal packing, and overall conformation of the structure.
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Affiliation(s)
- Julie A Dohm
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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45
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Kumar A, Mishra PC, Suhai S. Adiabatic Electron Affinities of the Polyhydrated Adenine−Thymine Base Pair: A Density Functional Study. J Phys Chem A 2005; 109:3971-9. [PMID: 16833718 DOI: 10.1021/jp0456178] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Adiabatic electron affinities (AEAs) of the adenine-thymine (AT) base pair surrounded by 5 and 13 water molecules have been studied by density functional theory (DFT). Geometries of neutral AT x nH2O and anionic (AT x nH2O)- complexes (n = 5 and 13) were fully optimized, and vibrational frequency analysis was performed at the B3LYP/6-31+G** level of theory. The optimized structures of the neutral (AT x nH2O) and (AT x nH2O)- complexes were found to be somewhat nonplanar. Some of the water molecules are displaced away from the AT ring plane and linked with one another by hydrogen bonds. The optimized structures of the complexes are found to be in a satisfactory agreement with the observed experimental and molecular dynamics simulation results. In the optimized anionic complexes, the thymine (T) moiety was found to be puckered, whereas the adenine (A) moiety remained almost planar. Natural population analysis (NPA) performed using the B3LYP/6-31+G** method shows that the thymine moiety in the anionic (AT x nH2O)- complexes (n = 5 and 13) has most of the excess electronic charge, i.e., approximately -0.87 and approximately -0.81 (in the unit of magnitude of the electronic charge), respectively. The zero-point energy corrected adiabatic electron affinities of the hydrated AT base pair were found to be positive both for n = 5 and 13 and have the values of 0.97 and 0.92 eV, respectively, which are almost three times the AEA of the AT base pair. The results show that the presence of water molecules appreciably enhances the EA of the base pair.
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Affiliation(s)
- Anil Kumar
- Department of Physics, Banaras Hindu University, Varanasi-221 005, India
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46
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Soares TA, Hünenberger PH, Kastenholz MA, Kräutler V, Lenz T, Lins RD, Oostenbrink C, van Gunsteren WF. An improved nucleic acid parameter set for the GROMOS force field. J Comput Chem 2005; 26:725-37. [PMID: 15770662 DOI: 10.1002/jcc.20193] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Over the past decades, the GROMOS force field for biomolecular simulation has primarily been developed for performing molecular dynamics (MD) simulations of polypeptides and, to a lesser extent, sugars. When applied to DNA, the 43A1 and 45A3 parameter sets of the years 1996 and 2001 produced rather flexible double-helical structures, in which the Watson-Crick hydrogen-bonding content was more limited than expected. To improve on the currently available parameter sets, the nucleotide backbone torsional-angle parameters and the charge distribution of the nucleotide bases are reconsidered based on quantum-chemical data. The new 45A4 parameter set resulting from this refinement appears to perform well in terms of reproducing solution NMR data and canonical hydrogen bonding. The deviation between simulated and experimental observables is now of the same order of magnitude as the uncertainty in the experimental values themselves.
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Affiliation(s)
- Thereza A Soares
- Laboratory of Physical Chemistry, Swiss Federal Institute of Technology, ETH-Hönggerberg, 8093 Zurich, Switzerland
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47
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Cooper RL, Lee SA. Differential Scanning Calorimetric Study of the Binding of the Water of Hydration to Deoxyadenosine. J Biomol Struct Dyn 2004; 22:375-80. [PMID: 15473711 DOI: 10.1080/07391102.2004.10507009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Differential scanning calorimetry was used to study the water of hydration in powder samples of deoxyadenosine (dA), a naturally occurring nucleoside. Though water of crystallization is present in samples which have not undergone heat treatment previously, dA was found to rehydrate at room temperature only at relative humidities (RHs) of 88% and higher. Rehydrated samples exhibited a single endothermic peak. At 95% RH, its activation energy was 1.61 +/- 0.06 eV and had an enthalpy change of 190 +/- 30 J/g. Experiments between 88 and 95% RH revealed that the energies are independent of RH, to within experimental error. This range of humidity corresponds to secondary hydration in DNA.
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Affiliation(s)
- R L Cooper
- Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606, USA
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48
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Abstract
Nucleic acids are characterized by a vast structural variability. Secondary structural conformations include the main polymorphs A, B, and Z, cruciforms, intrinsic curvature, and multistranded motifs. DNA secondary motifs are stabilized and regulated by the primary base sequence, contextual effects, environmental factors, as well as by high-order DNA packaging modes. The high-order modes are, in turn, affected by secondary structures and by the environment. This review is concerned with the flow of structural information among the hierarchical structural levels of DNA molecules, the intricate interplay between the various factors that affect these levels, and the regulation and physiological significance of DNA high-order structures.
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Affiliation(s)
- Abraham Minsky
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel.
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49
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Real AN, Greenall RJ. Influence of Spermine on DNA Conformation in a Molecular Dynamics Trajectory of d(CGCGAATTCGCG)2: Major Groove Binding by One Spermine Molecule Delays the A→B Transition. J Biomol Struct Dyn 2004; 21:469-88. [PMID: 14692792 DOI: 10.1080/07391102.2004.10506941] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The effect of spermine on the A-DNA to B-DNA transition in d(CGCGAATTCGCG)(2) has been investigated by five A-start molecular dynamics simulations, using the Cornell et al. potential. In the absence of spermine an A-->B transition is initiated immediately and the DNA becomes equidistant from the A- and B-forms at 200ps. In three DNA-spermine simulations, when a spermine is located across the major groove of A-DNA in one of three different initial locations, the time taken to reach equidistance from the A- and B-forms is delayed until 800, 950 or 1000ps. In each case the A-form appears to be temporarily stabilized by spermine's electrostatic interactions with phosphates on both sides of the major groove. The onset of the A-->B transition can be correlated with the spermine losing contact with phosphates on one side of the groove and with A-like --> B-like sugar pucker transitions in the vicinity of the spermine bridge. However in the fifth trajectory, in which the spermine initially threads from the major groove via the backbone into the minor groove, the B-->A transition occurs rapidly once again and the DNA is equidistant between the A- and B-forms within 300ps. This indicates that the mere presence of spermine is insufficient to delay the transition and that major groove binding stabilizes A-DNA.
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Affiliation(s)
- Alan N Real
- Department of Physics, University of York, York, YO10 5DD, United Kingdom
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50
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Rozners E, Moulder J. Hydration of short DNA, RNA and 2'-OMe oligonucleotides determined by osmotic stressing. Nucleic Acids Res 2004; 32:248-54. [PMID: 14715922 PMCID: PMC373285 DOI: 10.1093/nar/gkh175] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Studies on hydration are important for better understanding of structure and function of nucleic acids. We compared the hydration of self-complementary DNA, RNA and 2'-O-methyl (2'-OMe) oligonucleotides GCGAAUUCGC, (UA)6 and (CG)3 using the osmotic stressing method. The number of water molecules released upon melting of oligonucleotide duplexes, Delta(n)W, was calculated from the dependence of melting temperature on water activity and the enthalpy, both measured with UV thermal melting experiments. The water activity was changed by addition of ethylene glycol, glycerol and acetamide as small organic co-solutes. The Delta(n)W was 3-4 for RNA duplexes and 2-3 for DNA and 2'-OMe duplexes. Thus, the RNA duplexes were hydrated more than the DNA and the 2'-OMe oligonucleotide duplexes by approximately one to two water molecules depending on the sequence. Consistent with previous studies, GC base pairs were hydrated more than AU pairs in RNA, whereas in DNA and 2'-OMe oligonucleotides the difference in hydration between these two base pairs was relatively small. Our data suggest that the better hydration of RNA contributes to the increased enthalpic stability of RNA duplexes compared with DNA duplexes.
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Affiliation(s)
- Eriks Rozners
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA.
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