1
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Duan M, Li Y, Zhang F, Huang Q. Assessing B-Z DNA Transitions in Solutions via Infrared Spectroscopy. Biomolecules 2023; 13:964. [PMID: 37371544 DOI: 10.3390/biom13060964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/25/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Z-DNA refers to the left-handed double-helix DNA that has attracted much attention because of its association with some specific biological functions. However, because of its low content and unstable conformation, Z-DNA is normally difficult to observe or identify. Up to now, there has been a lack of unified or standard analytical methods among diverse techniques for probing Z-DNA and its transformation conveniently. In this work, NaCl, MgCl2, and ethanol were utilized to induce d(GC)8 from B-DNA to Z-DNA in vitro, and Fourier transform infrared (FTIR) spectroscopy was employed to monitor the transformation of Z-DNA under different induction conditions. The structural changes during the transformation process were carefully examined, and the DNA chirality alterations were validated by the circular dichroism (CD) measurements. The Z-DNA characteristic signals in the 1450 cm-1-900 cm-1 region of the d(GC)8 infrared (IR) spectrum were observed, which include the peaks at 1320 cm-1, 1125 cm-1 and 925 cm-1, respectively. The intensity ratios of A1320/A970, A1125/A970, and A925/A970 increased with Z-DNA content in the transition process. Furthermore, compared with the CD spectra, the IR spectra showed higher sensitivity to Z-DNA, providing more information about the molecular structure change of DNA. Therefore, this study has established a more reliable FTIR analytical approach to assess BZ DNA conformational changes in solutions, which may help the understanding of the Z-DNA transition mechanism and promote the study of Z-DNA functions in biological systems.
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Affiliation(s)
- Mengmeng Duan
- Henan Key Laboratory of Ion-Beam Bioengineering, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China
| | - Yalin Li
- School of Food and Biological Engineering, Henan University of Animal Husbandry and Economy, Zhengzhou 450047, China
| | - Fengqiu Zhang
- Henan Key Laboratory of Ion-Beam Bioengineering, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China
| | - Qing Huang
- CAS Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Institute of Intelligent Machines, Hefei Institutes of Physical Sciences, Chinese Academy of Sciences, Hefei 230031, China
- Science Island Branch of Graduate School, University of Science and Technology, Hefei 230026, China
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2
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Tucker MR, Piana S, Tan D, LeVine MV, Shaw DE. Development of Force Field Parameters for the Simulation of Single- and Double-Stranded DNA Molecules and DNA-Protein Complexes. J Phys Chem B 2022; 126:4442-4457. [PMID: 35694853 PMCID: PMC9234960 DOI: 10.1021/acs.jpcb.1c10971] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
![]()
Although molecular
dynamics (MD) simulations have been used extensively
to study the structural dynamics of proteins, the role of MD simulation
in studies of nucleic acid based systems has been more limited. One
contributing factor to this disparity is the historically lower level
of accuracy of the physical models used in such simulations to describe
interactions involving nucleic acids. By modifying nonbonded and torsion
parameters of a force field from the Amber family of models, we recently
developed force field parameters for RNA that achieve a level of accuracy
comparable to that of state-of-the-art protein force fields. Here
we report force field parameters for DNA, which we developed by transferring
nonbonded parameters from our recently reported RNA force field and
making subsequent adjustments to torsion parameters. We have also
modified the backbone charges in both the RNA and DNA parameter sets
to make the treatment of electrostatics compatible with our recently
developed variant of the Amber protein and ion force field. We name
the force field resulting from the union of these three parameter
sets (the new DNA parameters, the revised RNA parameters, and the
existing protein and ion parameters) DES-Amber. Extensive
testing of DES-Amber indicates that it can describe the thermal stability
and conformational flexibility of single- and double-stranded DNA
systems with a level of accuracy comparable to or, especially for
disordered systems, exceeding that of state-of-the-art nucleic acid
force fields. Finally, we show that, in certain favorable cases, DES-Amber
can be used for long-timescale simulations of protein–nucleic
acid complexes.
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Affiliation(s)
| | - Stefano Piana
- D. E. Shaw Research, New York, New York 10036, United States
| | - Dazhi Tan
- D. E. Shaw Research, New York, New York 10036, United States
| | | | - David E Shaw
- D. E. Shaw Research, New York, New York 10036, United States.,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, New York 10032, United States
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3
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Possible Physical Basis of Mirror Symmetry Effect in Racemic Mixtures of Enantiomers: From Wallach’s Rule, Nonlinear Effects, B–Z DNA Transition, and Similar Phenomena to Mirror Symmetry Effects of Chiral Objects. Symmetry (Basel) 2020. [DOI: 10.3390/sym12060889] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Effects associated with mirror symmetry may be underlying for a number of phenomena in chemistry and physics. Increase in the density and melting point of the 50%L/50%D collection of enantiomers of a different sign (Wallach’s rule) is probably based on a physical effect of the mirror image. The catalytic activity of metal complexes with racemic ligands differs from the corresponding complexes with enantiomers as well (nonlinear effect). A similar difference in the physical properties of enantiomers and racemate underlies L/D inversion points of linear helical macromolecules, helical nanocrystals of magnetite and boron nitride etc., B–Z DNA transition and phenomenon of mirror neurons may have a similar nature. Here we propose an explanation of the Wallach effect along with some similar chemical, physical, and biological phenomena related to mirror image.
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4
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Wilson AL, Outeiral C, Dowd SE, Doig AJ, Popelier PLA, Waltho JP, Almond A. Deconvolution of conformational exchange from Raman spectra of aqueous RNA nucleosides. Commun Chem 2020; 3:56. [PMID: 36703475 PMCID: PMC9814580 DOI: 10.1038/s42004-020-0298-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 04/06/2020] [Indexed: 01/29/2023] Open
Abstract
Ribonucleic acids (RNAs) are key to the central dogma of molecular biology. While Raman spectroscopy holds great potential for studying RNA conformational dynamics, current computational Raman prediction and assignment methods are limited in terms of system size and inclusion of conformational exchange. Here, a framework is presented that predicts Raman spectra using mixtures of sub-spectra corresponding to major conformers calculated using classical and ab initio molecular dynamics. Experimental optimization allowed purines and pyrimidines to be characterized as predominantly syn and anti, respectively, and ribose into exchange between equivalent south and north populations. These measurements are in excellent agreement with Raman spectroscopy of ribonucleosides, and previous experimental and computational results. This framework provides a measure of ribonucleoside solution populations and conformational exchange in RNA subunits. It complements other experimental techniques and could be extended to other molecules, such as proteins and carbohydrates, enabling biological insights and providing a new analytical tool.
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Affiliation(s)
- Alex L. Wilson
- grid.5379.80000000121662407Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Science, Faculty of Science and Engineering, The University of Manchester, M1 7DN Manchester, UK
| | - Carlos Outeiral
- grid.5379.80000000121662407Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Science, Faculty of Science and Engineering, The University of Manchester, M1 7DN Manchester, UK
| | - Sarah E. Dowd
- grid.5379.80000000121662407Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Science, Faculty of Science and Engineering, The University of Manchester, M1 7DN Manchester, UK
| | - Andrew J. Doig
- grid.5379.80000000121662407Division of Neuroscience and Experimental Psychology, Michael Smith Building, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, M13 9PT Manchester, UK
| | - Paul L. A. Popelier
- grid.5379.80000000121662407Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Science, Faculty of Science and Engineering, The University of Manchester, M1 7DN Manchester, UK
| | - Jonathan P. Waltho
- grid.5379.80000000121662407Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Science, Faculty of Science and Engineering, The University of Manchester, M1 7DN Manchester, UK ,grid.11835.3e0000 0004 1936 9262Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, The University of Sheffield, S10 2TN Sheffield, UK
| | - Andrew Almond
- grid.5379.80000000121662407Manchester Institute of Biotechnology and Department of Chemistry, School of Natural Science, Faculty of Science and Engineering, The University of Manchester, M1 7DN Manchester, UK
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5
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Сhiral and Racemic Fields Concept for Understanding of the Homochirality Origin, Asymmetric Catalysis, Chiral Superstructure Formation from Achiral Molecules, and B-Z DNA Conformational Transition. Symmetry (Basel) 2019. [DOI: 10.3390/sym11050649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The four most important and well-studied phenomena of mirror symmetry breaking of molecules were analyzed for the first time in terms of available common features and regularities. Mirror symmetry breaking of the primary origin of biological homochirality requires the involvement of an external chiral inductor (environmental chirality). All reviewed mirror symmetry breaking phenomena were considered from that standpoint. A concept of chiral and racemic fields was highly helpful in this analysis. A chiral gravitational field in combination with a static magnetic field (Earth’s environmental conditions) may be regarded as a hypothetical long-term chiral inductor. Experimental evidences suggest a possible effect of the environmental chiral inductor as a chiral trigger on the mirror symmetry breaking effect. Also, this effect explains a conformational transition of the right-handed double DNA helix to the left-handed double DNA helix (B-Z DNA transition) as possible DNA damage.
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6
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Linking Temperature, Cation Concentration and Water Activity for the B to Z Conformational Transition in DNA. Molecules 2018; 23:molecules23071806. [PMID: 30037061 PMCID: PMC6099936 DOI: 10.3390/molecules23071806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/05/2022] Open
Abstract
High concentrations of Na+ or [Co(NH3)6]3+ can induce the B to Z conformational transition in alternating (dC-dG) oligo and polynucleotides. The use of short DNA oligomers (dC-dG)4 and (dm5C-dG)4 as models can allow a thermodynamic characterization of the transition. Both form right handed double helical structures (B-DNA) in standard phosphate buffer with 115 mM Na+ at 25 °C. However, at 2.0 M Na+ or 200 μM [Co(NH3)6]3+, (dm5C-dG)4 assumes a left handed double helical structure (Z-DNA) while the unmethylated (dC-dG)4 analogue remains right handed under those conditions. We have previously demonstrated that the enthalpy of the transition at 25 °C for either inducer can be determined using isothermal titration calorimetry (ITC). Here, ITC is used to investigate the linkages between temperature, water activity and DNA conformation. We found that the determined enthalpy for each titration varied linearly with temperature allowing determination of the heat capacity change (ΔCp) between the initial and final states. As expected, the ΔCp values were dependent upon the cation (i.e., Na+ vs. [Co(NH3)6]3+) as well as the sequence of the DNA oligomer (i.e., methylated vs. unmethylated). Osmotic stress experiments were carried out to determine the gain or loss of water by the oligomer induced by the titration. The results are discussed in terms of solvent accessible surface areas, electrostatic interactions and the role of water.
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7
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Abstract
The complex conformational change from B-DNA to Z-DNA requires inversion of helix-handedness. Multiple degrees of freedom are intricately coupled during this transition, and formulating an appropriate reaction coordinate that captures the underlying complexity would be problematic. In this contribution, we adopt an alternative approach, based on the potential energy landscape perspective, to construct a kinetic transition network. Microscopic insight into the B → Z transition is provided in terms of geometrically defined discrete paths consisting of local minima and the transition states that connect them. We find that the inversion of handedness can occur via two competing mechanisms, either involving stretched intermediates, or a B-Z junction, in agreement with previous predictions. The organisation of the free energy landscape further suggests that this process is likely to be slow under physiological conditions. Our results represent a key step towards decoding the more intriguing features of the B → Z transition, such as the role of ionic strength and negative supercoiling in reshaping the landscape.
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Affiliation(s)
- Debayan Chakraborty
- Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, UK.
| | - David J Wales
- Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW, UK.
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8
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Lee S, Huh S. Measuring Fluorescence Anisotropy as One of Very Useful Analytical Methods to Obtain Detailed Information of the Complex Binding Interaction. B KOREAN CHEM SOC 2017. [DOI: 10.1002/bkcs.11090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Seongkyung Lee
- Department of Biochemistry; Chungnam National University; Daejeon 34134 Korea
| | - Sungho Huh
- Department of Biochemistry; Chungnam National University; Daejeon 34134 Korea
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9
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Guéron M, Plateau P, Filoche M. Studies of the B-Z transition of DNA: The temperature dependence of the free-energy difference, the composition of the counterion sheath in mixed salt, and the preparation of a sample of the 5'-d[T-(m(5) C-G)12 -T] duplex in pure B-DNA or Z-DNA form. Biopolymers 2017; 105:369-84. [PMID: 26900058 DOI: 10.1002/bip.22824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/08/2016] [Accepted: 02/16/2016] [Indexed: 01/24/2023]
Abstract
It is often envisioned that cations might coordinate at specific sites of nucleic acids and play an important structural role, for instance in the transition between B-DNA and Z-DNA. However, nucleic acid models explicitly devoid of specific sites may also exhibit features previously considered as evidence for specific binding. Such is the case of the "composite cylinder" (or CC) model which spreads out localized features of DNA structure and charge by cylindrical averaging, while sustaining the main difference between the B and Z structures, namely the better immersion of the B-DNA phosphodiester charges in the solution. Here, we analyze the non-electrostatic component of the free-energy difference between B-DNA and Z-DNA. We also compute the composition of the counterion sheath in a wide range of mixed-salt solutions and of temperatures: in contrast with the large difference of composition between the B-DNA and Z-DNA forms, the temperature dependence of sheath composition, previously unknown, is very weak. In order to validate the model, the mixed-salt predictions should be compared to experiment. We design a procedure for future measurements of the sheath composition based on Anomalous Small-Angle X-ray Scattering and complemented by (31) P NMR. With due consideration for the kinetics of the B-Z transition and for the capacity of generating at will the B or Z form in a single sample, the 5'-d[T-(m(5) C-G)12 -T] 26-mer emerges as a most suitable oligonucleotide for this study. Finally, the application of the finite element method to the resolution of the Poisson-Boltzmann equation is described in detail. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 369-384, 2016.
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Affiliation(s)
- Maurice Guéron
- Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128, Palaiseau, France
| | - Pierre Plateau
- Laboratoire de Biochimie, Ecole polytechnique, CNRS, Université Paris-Saclay, 91128, Palaiseau Cedex, France
| | - Marcel Filoche
- Physique de la Matière Condensée, Ecole Polytechnique, CNRS, 91128, Palaiseau, France
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10
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Chandrasegaran S, Kan LS. Chemical Synthesis of Oligodeoxyribonucleotides on the Polystyrene Polymer Support. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.198500055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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11
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Das S, Kundu S, Suresh Kumar G. Quinacrine and 9-Amino Acridine Inhibit B-Z and B-HL Form DNA Conformational Transitions. DNA Cell Biol 2011; 30:525-35. [PMID: 21395448 DOI: 10.1089/dna.2010.1206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Suman Das
- Department of Chemistry, Jadavpur University, Kolkata, India
| | - Suprabhat Kundu
- Department of Chemistry, Jadavpur University, Kolkata, India
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12
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The conformational effect of para-substituted C8-arylguanine adducts on the B/Z-DNA equilibrium. Biophys Chem 2010; 154:41-8. [PMID: 21255902 DOI: 10.1016/j.bpc.2010.12.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 12/19/2010] [Accepted: 12/19/2010] [Indexed: 11/20/2022]
Abstract
The B form of DNA exists in equilibrium with the Z form and is mainly affected by sequence, electrostatic interactions, and steric effects. C8-purine substitution shifts the equilibrium toward the Z form though how this interaction overcomes the unfavorable electrostatic interactions and decrease in stacking in the Z form has not been determined. Here, a series of C8-arylguanine derivatives, bearing a para-substituent were prepared and the B/Z equilibrium determined. B/Z ratios were measured by CD and conformational effects of the aryl substitution determined by NMR spectroscopy and molecular modeling. The para-substituent was found to have a significant effect on the B/Z DNA equilibrium caused by altering base-pair stacking of the B form and modifying the hydration/ion shell of the B form. A unique melting temperature versus salt concentration was observed and provides evidence relevant to the mechanism of B/Z conformational interconversion.
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13
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Nikan M, Sherman JC. Cation-Complexation Behavior of Template-Assembled Synthetic G-Quartets. J Org Chem 2009; 74:5211-8. [DOI: 10.1021/jo9001245] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mehran Nikan
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, Canada V6T 1Z1
| | - John C. Sherman
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, Canada V6T 1Z1
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14
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Khanduri D, Collins S, Kumar A, Adhikary A, Sevilla MD. Formation of sugar radicals in RNA model systems and oligomers via excitation of guanine cation radical. J Phys Chem B 2008; 112:2168-78. [PMID: 18225886 DOI: 10.1021/jp077429y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In previous work, we have shown that photoexcitation of guanine cation radical (G*+) in frozen aqueous solutions of DNA and its model compounds at 143 K results in the formation of neutral sugar radicals with substantial yield. In this report, we present electron spin resonance (ESR) and theoretical (DFT) evidence regarding the formation of sugar radicals after photoexcitation of guanine cation radical (G*+) in frozen aqueous solutions of one-electron-oxidized RNA model compounds (nucleosides, nucleotides and oligomers) at 143 K. Specific sugar radicals C5'*, C3'* and C1'* were identified employing derivatives of Guo deuterated at specific sites in the sugar moiety, namely, C1'-, C2'-, C3'- and C5'-. These results suggest C2'* is not formed upon photoexcitation of G*+ in one-electron-oxidized Guo and deuterated Guo derivatives. Phosphate substitution at C5'- (i.e., in 5-GMP) hinders formation of C5'* via photoexcitation at 143 K but not at 77 K. For the RNA-oligomers studied, we observe on photoexcitation of oligomer-G*+ the formation of mainly C1'* and an unidentified radical with a ca. 28 G doublet. The hyperfine coupling constants of each of the possible sugar radicals were calculated employing the DFT B3LYP/6-31G* approach for comparison to experiment. This work shows that formation of specific neutral sugar radicals occurs via photoexcitation of guanine cation radical (G*+) in RNA systems but not by photoexcitation of its N1 deprotonated species (G(-H)*). Thus, our mechanism regarding neutral sugar formation via photoexcitation of base cation radicals in DNA appears to be valid for RNA systems as well.
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Affiliation(s)
- Deepti Khanduri
- Department of Chemistry, Oakland University, Rochester, Michigan 48309, USA
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15
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Ferreira JM, Sheardy RD. Enthalpy of the B-to-Z conformational transition of a DNA oligonucleotide determined by isothermal titration calorimetry. Biophys J 2006; 91:3383-9. [PMID: 16920828 PMCID: PMC1614508 DOI: 10.1529/biophysj.106.084145] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 07/28/2006] [Indexed: 11/18/2022] Open
Abstract
The influence of high concentrations of Na(+) or [Co(NH(3))(6)](3+) on the conformation of two related DNA oligomers was investigated by circular dichroism spectropolarimetry (CD), isothermal titration calorimetry (ITC), and differential scanning calorimetry (DSC). As revealed by CD, DNA oligomers, (dC-dG)(4) and (dm(5)C-dG)(4), both form right-handed double helical structures (B-DNA) in standard phosphate buffer with 115 mM Na(+) at 25 degrees C. However, at 2.0 M Na(+) or 200 microM [Co(NH(3))(6)](3+), (dm(5)C-dG)(4) assumes a left-handed double helical structure (Z-DNA), whereas the unmethylated (dC-dG)(4) analog remains right-handed under those conditions. ITC was then used to determine the enthalpy change upon increasing the concentration of either Na(+) or [Co(NH(3))(6)](3+) for both DNA oligomers at 25 degrees C. The titration with Na(+) resulted in endothermic isotherms with (dm(5)C-dG)(4) being more endothermic than (dC-dG)(4) by 700 cal/mol basepair. In contrast, titration with [Co(NH(3))(6)](3+) resulted in exothermic isotherms with (dC-dG)(4) being more exothermic than (dm(5)C-dG)(4) by 720 cal/mol basepair. We attribute the enthalpy difference to the conformational transition from B-form DNA to Z-form DNA for (dm(5)C-dG)(4), a transition which does not occur for the unmethylated (dC-dG)(4). The value of approximately 700 cal/mol basepair for the enthalpy of the B-Z transition compares favorably with previously published results obtained by different techniques. DSC was used to monitor the duplex to single strand transitions for both oligomers under the different concentrations. These results indicated that methylation of the cytidine destabilizes (dm(5)C-dG)(4) relative to (dC-dG)(4). Coupling the DSC data with the ITC data allowed construction of a thermodynamic cycle which gives insight into the influence of both temperature and ionic strength on the heat content of the two DNA systems studied. Further, this study reveals the utility of using ITC for determinations of transition enthalpies with the appropriate choice of control.
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Affiliation(s)
- Jaime M Ferreira
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey 07079, USA
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16
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Thibaudeau C, Chattopadhyaya J. The Information Transmission from the Nucleobase Drives the Sugar-Phosphate Backbone Conformation in the Nucleotide Wire. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/07328319808004691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Christophe Thibaudeau
- a Department of Bioorganic Chemistry , University of Uppsala , Box 581, Biomedical Centre, S-751 23 , Uppsala , Sweden
| | - Jyoti Chattopadhyaya
- a Department of Bioorganic Chemistry , University of Uppsala , Box 581, Biomedical Centre, S-751 23 , Uppsala , Sweden
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17
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Thibaudeau C, Chattopadhyaya J. The Discovery of Intramolecular Stereoelectronic Forces That Drive The Sugar Conformation in Nucleosides and Nucleotides. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/07328319708002912] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- C. Thibaudeau
- a Department of Bioorganic Chemistry , Box 581 Biomedical Center, Uppsala University , Uppsala , S-751 23 , Sweden
| | - J. Chattopadhyaya
- a Department of Bioorganic Chemistry , Box 581 Biomedical Center, Uppsala University , Uppsala , S-751 23 , Sweden
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18
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Matta CF, Castillo N, Boyd RJ. Extended weak bonding interactions in DNA: pi-stacking (base-base), base-backbone, and backbone-backbone interactions. J Phys Chem B 2006; 110:563-78. [PMID: 16471569 DOI: 10.1021/jp054986g] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report on several weak interactions in nucleic acids, which, collectively, can make a nonnegligible contribution to the structure and stability of these molecules. Fragments of DNA were obtained from previously determined accurate experimental geometries and their electron density distributions calculated using density functional theory (DFT). The electron densities were analyzed topologically according to the quantum theory of atoms in molecules (AIM). A web of closed-shell bonding interactions is shown to connect neighboring base pairs in base-pair duplexes and in dinuleotide steps. This bonding underlies the well-known pi-stacking interaction between adjacent nucleic acid bases and is characterized topologically for the first time. Two less widely appreciated modes of weak closed-shell interactions in nucleic acids are also described: (i) interactions between atoms in the bases and atoms belonging to the backbone (base-backbone) and (ii) interactions among atoms within the backbone itself (backbone-backbone). These interactions include hydrogen bonding, dihydrogen bonding, hydrogen-hydrogen bonding, and several other weak closed-shell X-Y interactions (X, Y = O, N, C). While each individual interaction is very weak and typically accompanied by perhaps 0.5-3 kcal/mol, the sum total of these interactions is postulated to play a role in stabilizing the structure of nucleic acids. The Watson-and-Crick hydrogen bonding is also characterized in detail at the experimental geometries as a prelude to the discussion of the modes of interactions listed in the title.
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Affiliation(s)
- Chérif F Matta
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J3
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19
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Popenda M, Milecki J, Adamiak RW. High salt solution structure of a left-handed RNA double helix. Nucleic Acids Res 2004; 32:4044-54. [PMID: 15292450 PMCID: PMC506817 DOI: 10.1093/nar/gkh736] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Right-handed RNA duplexes of (CG)n sequence undergo salt-induced helicity reversal, forming left-handed RNA double helices (Z-RNA). In contrast to the thoroughly studied Z-DNA, no Z-RNA structure of natural origin is known. Here we report the NMR structure of a half-turn, left-handed RNA helix (CGCGCG)2 determined in 6 M NaClO4. This is the first nucleic acid motif determined at such high salt. Sequential assignments of non-exchangeable proton resonances of the Z-form were based on the hitherto unreported NOE connectivity path [H6(n)-H5'/H5''(n)-H8(n+1)-H1'(n+1)-H6(n+2)] found for left-handed helices. Z-RNA structure shows several conformational features significantly different from Z-DNA. Intra-strand but no inter-strand base stacking was observed for both CpG and GpC steps. Helical twist angles for CpG steps have small positive values (4-7 degrees), whereas GpC steps have large negative values (-61 degrees). In the full-turn model of Z-RNA (12.4 bp per turn), base pairs are much closer to the helix axis than in Z-DNA, thus both the very deep, narrow minor groove with buried cytidine 2'-OH groups, and the major groove are well defined. The 2'-OH group of cytidines plays a crucial role in the Z-RNA structure and its formation; 2'-O-methylation of cytidine, but not of guanosine residues prohibits A to Z helicity reversal.
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Affiliation(s)
- Mariusz Popenda
- Laboratory of Structural Chemistry of Nucleic Acids, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12-14, 61-704 Poznań, Poland and Faculty of Chemistry, Adam Mickiewicz University, Poznań, Poland
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20
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Acharya P, Chattopadhyaya J. The hydrogen bonding and hydration of 2'-OH in adenosine and adenosine 3'-ethyl phosphate. J Org Chem 2002; 67:1852-65. [PMID: 11895403 DOI: 10.1021/jo010960j] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 2'-OH group has major structural implications in the recognition, processing, and catalytic properties of RNA. We report here intra- and intermolecular H-bonding of 2'-OH in adenosine 3'-ethyl phosphate (1), 3'-deoxyadenosine (2), and adenosine (3) by both temperature- and concentration-dependent NMR studies, as well as by detailed endo ((3)J(H,H)) and exocyclic ((3)J(H,OH)) coupling constant analyses. We have also examined the nature of hydration and exchange processes of 2'-OH with water by a combination of NOESY and ROESY experiments in DMSO-d(6) containing 2 mol % HOD. The NMR-constrained molecular modeling (by molecular mechanics as well as by ab initio methods both in the gas and solution phase) has been used to characterize the energy minima among the four alternative dihedrals possible from the solution of the Karplus equation for (3)J(H2',OH) and (3)J(H3',OH) to delineate the preferred orientation of 2'-O-H proton in 1 and 2 as well as for 2'/3'-O-H protons in 3. The NMR line shape analysis of 2'-OH gave the DeltaG(H-bond)(298K) of 7.5 kJ mol(-1) for 1 and 8.4 kJ mol(-1) for 3; similar analyses of the methylene protons of 3'-ethyl phosphate moiety in 1 also gave comparable DeltaG(H-bond)(298K) of 7.3 kJ mol(-1). The donor nature of the 2'-OH in the intramolecular H-bonding in 3 is evident from its relatively reduced flexibility [-TDeltaS++](2'-OH) = -17.9(+/-0.5) kJ mol(-1)] because of the loss of conformational freedom owing to the intramolecular 2'O-H...O3' H-bonding, compared to the acceptor 3'-OH in 3 [-TDeltaS++](3'-OH) = -19.8 (+/- 0.6) kJ mol(-1)] at 298 K. The presence of intramolecular 2'-OH...O3' H-bonding in 3 is also corroborated by the existence of weak long-range (4)J(H2',OH3') in 3 (i.e., W conformation of H2'-C2'-C3'-O3'-H) as well as by (3)J(H,OH) dependent orientation of the 2'- and 3'-OH groups. The ROESY spectra for 1 and 3 at 308 K, in DMSO-d(6), show a clear positive ROE contact of both 2'- and 3'-OH with water. The presence of a hydrophilic 3'-phosphate group in 1 causes a much higher water activity in the vicinity of its 2'-OH, which in turn causes the 2'-OH to exchange faster, culminating in a shorter exchange lifetime (tau) for 2'-OH proton with HOD in 1 (tau2'-OH: 489 ms) compared to that in 3 (tau2'-OH: 6897 ms). The activation energy (E(a)) of the exchange with the bound-water for 2'- and 3'-OH in 3 (48.3 and 45.0 kJ mol(-1), respectively) is higher compared to that of 2'-OH in 1 (31.9 kJ mol(-1)), thereby showing that the kinetic availability of hydrated 2'-OH in 1 for any inter- and intramolecular interactions, in general, is owing to the vicinal 3'-phosphate residue. It also suggests that 2'-OH in native RNA can mediate other inter- or intramolecular interactions only in competition with the bound-water, depending upon the specific chemical nature and spatial orientation of other functions with potential for hydrogen bonding in the neighborhood. This availability of the bound water around 2'-OH in RNA would, however, be dictated by whether the vicinal phosphate is exposed to the bulk water or not. This implies that relatively poor hydration around a specific 2'-OH across a polyribonucleotide chain, owing to some hydrophobic microenvironmental pocket around that hydroxyl, may make it more accessible to interact with other donor or acceptor functions for H-bonding interactions, which might then cause the RNA to fold in a specific manner generating a new motif leading to specific recognition and function. Alternatively, a differential hydration of a specific 2'-OH may modulate its nucleophilicity to undergo stereospecific transesterification reaction as encountered in ubiquitous splicing of pre-mRNA to processed RNA or RNA catalysis, in general.
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Affiliation(s)
- Parag Acharya
- Department of Bioorganic Chemistry, Box 581, Biomedical Centre, University of Uppsala, S-751 23 Uppsala, Sweden
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21
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Gundhi P, Chary K, Hosur R. Direct observation of (H8,H6)-Hr J
-coupling correlations in oligonucleotides for unambiguous resonance assignments. FEBS Lett 2001. [DOI: 10.1016/0014-5793(85)81000-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Pervushin K. The use of TROSY for detection and suppression of conformational exchange NMR line broadening in biological macromolecules. JOURNAL OF BIOMOLECULAR NMR 2001; 20:275-85. [PMID: 11519750 DOI: 10.1023/a:1011208109853] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The interference between conformational exchange-induced time-dependent variations of chemical shifts in a pair of scalar coupled 1H and 15N spins is used to construct novel TROSY-type NMR experiments to suppress NMR signal loss in [15N,1H]-correlation spectra of a 14-mer DNA duplex free in solution and complexed with the Antp homeodomain. An analysis of double- and zero-quantum relaxation rates of base 1H-15N moieties showed that for certain residues the contribution of conformational exchange-induced transverse relaxation might represent a dominant relaxation mechanism, which, in turn, can be effectively suppressed by TROSY. The use of the new TROSY method for exchange-induced transverse relaxation optimization is illustrated with two new experiments. 2D h1J(HN),h2J(NN) quantitative [15N,1H]-TROSY to measure h1J(HN) and h2J(NN) scalar coupling constants across hydrogen bonds in nucleic acids, and 2D (h2J(NN) + h1J(NH))-correlation-[15N,1H]-TROSY to correlate 1H(N) chemical shifts of bases with the chemical shifts of the tertiary 15N spins across hydrogen bonds using the sum of the trans-hydrogen bond coupling constants in nucleic acids.
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Affiliation(s)
- K Pervushin
- Laboratorium für Physikalische Chemie, Eidgenössische Technische Hochschule, Zürich, Switzerland
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23
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Mauffret O, El Amri C, Santamaria F, Tevanian G, Rayner B, Fermandjian S. A two B-Z junction containing DNA resolves into an all right-handed double-helix. Nucleic Acids Res 2000; 28:4403-9. [PMID: 11071926 PMCID: PMC113876 DOI: 10.1093/nar/28.22.4403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Natural and artificial oligonucleotides are capable of assuming many different conformations and functions. Here we present results of an NMR restrained molecular modelling study on the conformational preferences of the modified decanucleotide d((m)C1G2(m)C3G4C5(L)G6(L)(m)C7G8(m)C9G10) .d((m)C11G12(m)C13G14C15(L)G (L)16(m)C17-G18(m)C19G20 ) which contains L deoxynucleotides in its centre. This chimeric DNA was expected to form a right-left-right-handed B-type double-helix (BB*B) at low salt concentration. Actually, it matured into a fully right-handed double helix with its central C(L)pG(L) core forming a right-handed Z-DNA helix embedded in a B-DNA matrix (BZ*B). The interplay between base-base and base-sugar stackings within the core and its immediately adjacent residues was found to be critical in ensuring the stabilisation of the right-handed helix. The structure could serve as a model for the design of antisense oligonucleotides resistant to nucleases and capable of hybridising to natural DNAs and RNAs.
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Affiliation(s)
- O Mauffret
- Département de Biologie et Pharmacologie Structurales, UMR 8532 CNRS, PR2, Institut Gustave-Roussy, 39 rue Camille-Desmoulins, 94805 Villejuif Cedex, France
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24
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Li Z, Kim HY, Tamura PJ, Harris CM, Harris TM, Stone MP. Intercalation of the (1S,2R,3S,4R)-N6-[1-(1,2,3,4-tetrahydro-2,3, 4-trihydroxybenz[a]anthracenyl)]-2'-deoxyadenosyl adduct in an oligodeoxynucleotide containing the human N-ras codon 61 sequence. Biochemistry 1999; 38:16045-57. [PMID: 10587427 DOI: 10.1021/bi9903650] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The (1S,2R,3S,4R)-N(6)-[1-(1,2,3,4-tetrahydro-2,3, 4-trihydroxybenz[a]anthracenyl)]-2'-deoxyadenosyl adduct at X6 of 5'-d(CGGACXAGAAG)-3'.5'-d(CTTCTTGTCCG)-3', incorporating codons 60, 61 (underlined), and 62 of the human N-ras protooncogene, results from trans opening of (1R,2S,3S,4R)-1,2-epoxy-1,2,3, 4-tetrahydrobenz[a]anthracenyl-3,4-diol by the exocyclic N6 of adenine. Two conformations of this adduct exist, in slow exchange on the NMR time scale. A structure for the major conformation, which represents approximately 80% of the population, is presented. In this conformation, an anti glycosidic torsion angle is observed for all nucleotides, including S,R,S,RA6. The refined structure is a right-handed duplex, with the benz[a]anthracene moiety intercalated on the 3'-face of the modified base pair, from the major groove. It is located between S,R,S,RA6.T17 and A7.T16. Intercalation is on the opposite face of the modified S,R,S,RA6.T17 base pair as compared to the (1R,2S,3R,4S)-N6-[1-(1,2,3,4-tetrahydro-2, 3,4-trihydroxybenz[a]anthracenyl)]-2'-deoxyadenosyl adduct, which intercalated 5' to the modified R,S,R,SA6.T17 base pair [Li, Z. , Mao, H., Kim, H.-Y., Tamura, P. J., Harris, C. M., Harris, T. M., and Stone, M. P. (1999) Biochemistry 38, 2969-2981]. The spectroscopic data do not allow refinement of the minor conformation, but suggest that the adenyl moiety in the modified nucleoti111S,R, S,RA6 adopts a syn glycosidic torsion angle. Thus, the minor conformation may create greater distortion of the DNA duplex. The results are discussed in the context of site-specific mutagenesis studies which reveal that the S,R,S,RA6 lesion is less mutagenic than the R,S,R,SA6 lesion.
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Affiliation(s)
- Z Li
- Department of Chemistry, Center in Molecular Toxicology, Vanderbilt University, Nashville, TN 37235, USA
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26
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Schuerman GS, Van Meervelt L, Loakes D, Brown DM, Kong Thoo Lin P, Moore MH, Salisbury SA. A thymine-like base analogue forms wobble pairs with adenine in a Z-DNA duplex. J Mol Biol 1998; 282:1005-11. [PMID: 9753550 DOI: 10.1006/jmbi.1998.2080] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The DNA hexamer d(CACGPG), in which dP is the ambivalent pyrimidine nucleoside analogue 2'-deoxy-beta-d-ribofuranosyl-(6H,8H-3, 4-dihydropyrimido[4,5-c][1,2]oxazin-7-one), crystallises as a left-handed Z-DNA duplex. X-ray analysis at 1.5 A shows that both P. A base-pairs are of the wobble type. This result appears inconsistent with other evidence from hybridisation and NMR studies of P-containing oligonucleotides, which suggests that, while P can form stable base-pairs with either A or G, thymine-like properties are more pronounced. Thermal denaturation experiments over a range of solution pH values indicate that protonation of the P.A base-pairs is unlikely to be responsible for the anomalous behaviour. No specific crystal packing effects can be identfied as an explanation, and it is concluded that base stacking and other interactions between nucleotide residues in Z-DNA are responsible.
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Affiliation(s)
- G S Schuerman
- Departement Scheikunde, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee, B-3001, Belgium
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27
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Thibaudeau C, Kumar A, Bekiroglu S, Matsuda A, Marquez VE, Chattopadhyaya J. NMR Conformation of (−)-β-d-Aristeromycin and Its 2‘-Deoxy and 3‘-Deoxy Counterparts in Aqueous Solution. J Org Chem 1998. [DOI: 10.1021/jo980364y] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- C. Thibaudeau
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, Laboratory of Medicinal Chemistry, DPT, DCT, National Cancer Institute, NIH, Bethesda, Maryland 20892, and Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, Japan
| | - A. Kumar
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, Laboratory of Medicinal Chemistry, DPT, DCT, National Cancer Institute, NIH, Bethesda, Maryland 20892, and Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, Japan
| | - S. Bekiroglu
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, Laboratory of Medicinal Chemistry, DPT, DCT, National Cancer Institute, NIH, Bethesda, Maryland 20892, and Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, Japan
| | - A. Matsuda
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, Laboratory of Medicinal Chemistry, DPT, DCT, National Cancer Institute, NIH, Bethesda, Maryland 20892, and Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, Japan
| | - V. E. Marquez
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, Laboratory of Medicinal Chemistry, DPT, DCT, National Cancer Institute, NIH, Bethesda, Maryland 20892, and Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, Japan
| | - J. Chattopadhyaya
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, Laboratory of Medicinal Chemistry, DPT, DCT, National Cancer Institute, NIH, Bethesda, Maryland 20892, and Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060, Japan
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28
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Thibaudeau C, Plavec J, Chattopadhyaya J. A New Generalized Karplus-Type Equation Relating Vicinal Proton-Fluorine Coupling Constants to H−C−C−F Torsion Angles. J Org Chem 1998. [DOI: 10.1021/jo980144k] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christophe Thibaudeau
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, and National Institute of Chemistry, Hajdrihova 19, SI-1115 Ljubljana, Slovenia
| | - Janez Plavec
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, and National Institute of Chemistry, Hajdrihova 19, SI-1115 Ljubljana, Slovenia
| | - Jyoti Chattopadhyaya
- Department of Bioorganic Chemistry, Box 581, Biomedical Center, University of Uppsala, S-751 23 Uppsala, Sweden, and National Institute of Chemistry, Hajdrihova 19, SI-1115 Ljubljana, Slovenia
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29
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Thibaudeau C, Földesi A, Chattopadhyaya J. The quantitation of the competing energetics of the stereoelectronic and steric effects of the 3′-OH and the aglycone in the α-versus & by 1H-NMR. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(97)10403-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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30
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Thibaudeau C, Földesi A, Chattopadhyaya J. The first experimental evidence for a larger medium-dependent flexibility of natural β--nucleosides compared to the α--nucleosides. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00909-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Sugiyama H, Kawai K, Matsunaga A, Fujimoto K, Saito I, Robinson H, Wang AH. Synthesis, structure and thermodynamic properties of 8-methylguanine-containing oligonucleotides: Z-DNA under physiological salt conditions. Nucleic Acids Res 1996; 24:1272-8. [PMID: 8614630 PMCID: PMC145791 DOI: 10.1093/nar/24.7.1272] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Various oligonucleotides containing 8-methylguanine (m8G) have been synthesized and their structures and thermodynamic properties investigated. Introduction Of M8G into DNA sequences markedly stabilizes the Z conformation under low salt conditions. The hexamer d(CGC[M8G]CG)2 exhibits a CD spectrum characteristic of the Z conformation under physiological salt conditions. The NOE-restrained refinement unequivocally demonstrated that d(CGC[m8G]CG)2 adopts a Z structure with all guanines in the syn conformation. The refined NMR structure is very similar to the Z form crystal structure of d(CGCGCG)2, with a root mean square deviation of 0.6 between the two structures. The contribution of m8G to the stabilization of Z-DNA has been estimated from the mid-point NaCl concentrations for the B-Z transition of various m8G-containing oligomers. The presence of m8G in d(CGC[m8G]CG)2 stabilizes the Z conformation by at least deltaG = -0.8 kcal/mol relative to the unmodified hexamer. The Z conformation was further stabilized by increasing the number of m8Gs incorporated and destabilized by incorporating syn-A or syn-T, found respectively in the (A,T)-containing alternating and non-alternating pyrimidine-purine sequences. The results suggest that the chemically less reactive m8G base is a useful agent for studying molecular interactions of Z-DNA or other DNA structures that incorporate syn-G conformation.
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Affiliation(s)
- H Sugiyama
- Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Japan
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32
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Thibaudeau C, Plavec J, Chattopadhyaya J. Quantitation of the pD Dependent Thermodynamics of the N ⇄ S Pseudorotational Equilibrium of the Pentofuranose Moiety in Nucleosides Gives a Direct Measurement of the Strength of the Tunable Anomeric Effect and the pKa of the Nucleobase†. J Org Chem 1996. [DOI: 10.1021/jo951124a] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- C. Thibaudeau
- Department of Bioorganic Chemistry, Box 581, Biomedical Centre, University of Uppsala, S-751 23 Uppsala, Sweden
| | - J. Plavec
- Department of Bioorganic Chemistry, Box 581, Biomedical Centre, University of Uppsala, S-751 23 Uppsala, Sweden
| | - J. Chattopadhyaya
- Department of Bioorganic Chemistry, Box 581, Biomedical Centre, University of Uppsala, S-751 23 Uppsala, Sweden
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Bornet O, Prévost C, Vovelle F, Chassignol M, Thuong NT, Lancelot G. Solution structure of oligonucleotides covalently linked to a psoralen derivative. Nucleic Acids Res 1995; 23:788-95. [PMID: 7708495 PMCID: PMC306761 DOI: 10.1093/nar/23.5.788] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Psoralen (pso) was attached via its C-5 position to the 5'-phosphate group of an oligodeoxynucleotide d(TAAGCCG) by a hexamethylene linker (m6). Complex formation between pso-m6-d(TAAGCCG) and the complementary strands d(CGGCTTA)[7-7mer] or d(CGGCTTAT)[7-8mer] was investigated by nuclear magnetic resonance in aqueous solution. Structural informations derived from DQF-COSY and NOESY maps, revealed that the mini double helix adopts a B-form conformation and that the deoxyriboses preferentially adopt a C2'-endo conformation. The nOe connectivities observed between the protons of the bases or the sugars in each duplex, and the protons of the psoralen and the hexamethylene chain, led us to propose a model involving an equilibrium between two conformations due to different locations of the psoralen. Upon UV-irradiation, the psoralen moiety cross-linked the two DNA strands at the level of 5'TpA3' sequences. NMR studies of the single major photo-cross-linked duplex pso-m6-d(TAAGCCG) and d(CGGCTTA) were performed. The stereochemistry of the diadduct is indeed cis-syn at both cyclobutane rings. In addition, the effects of this diadduct on the helical structure are analyzed in detail.
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Affiliation(s)
- O Bornet
- Centre de Biophysique Moléculaire, CNRS, Orléans, France
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35
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Potent cytotoxic metabolites from a Leptosphaeria species. Structure determination and conformational analysis. Tetrahedron 1995. [DOI: 10.1016/0040-4020(95)00102-e] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Affiliation(s)
- J Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90095, USA
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37
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Plavec J, Thibaudeau C, Viswanadham G, Sund C, Chattopadhyaya J. How does the 3′-phosphate drive the sugar conformation in DNA? ACTA ACUST UNITED AC 1994. [DOI: 10.1039/c39940000781] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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38
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Rousse B, Puri N, Viswanadham G, Agback P, Glemarec C, Sandström A, Sund C, Chattopadhyaya J. Solution conformation of hexameric & heptameric lariat-RNAs and their self-cleavage reactions which give products mimicking those from some catalytic RNAs (ribozymes). Tetrahedron 1994. [DOI: 10.1016/s0040-4020(01)80852-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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39
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Rousse B, Sund C, Glemarec C, Sandström A, Agback P, Chattopadhyaya J. Remarkable conformational change promoted by 3′-ethylphosphate at the branch-point of a tetrameric lariat-RNA dictates its self-cleavage reaction modelling some catalytic RNAs (ribozymes). Tetrahedron 1994. [DOI: 10.1016/s0040-4020(01)85346-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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40
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Votavová H, Sponar J. B-Z transition of poly(dG-m5dC).poly(dG-m5dC) in the presence of basic oligopeptides. Int J Biol Macromol 1993; 15:139-44. [PMID: 8329326 DOI: 10.1016/0141-8130(93)90016-f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The effect of basic oligopeptides (Lys-Ala-Ala)n and (Lys-Leu-Ala)n (n = 1-4) on the B-Z transition of poly(dG-m5dC).poly(dG-m5dC) in aqueous solution and in methanol-water mixtures was investigated by c.d. spectroscopy. In aqueous solution dimers and higher oligomers induce a transition to the Z conformation. These temperature dependent transitions are consistent with positive delta HB-Z values which depend on peptide composition. In the absence of peptides no transition can be observed. In the presence of peptides B-Z transition can be induced by small amount of methanol. The temperature dependence of this transition is consistent with a small, but definitely negative delta HB-Z. At high methanol concentration a transition to Z' type conformation was observed. In subcritical methanol concentrations B-Z transition can be induced by the addition of peptides. In this case the delta HB-Z values are again very small, but definitely positive. The effects of bulky hydrophobic peptide side chains, of the presence of methanol and the temperature dependences are consistent with an important contribution of hydrophobic interactions in maintaining the stability of the Z DNA-peptide complex.
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Affiliation(s)
- H Votavová
- Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, Prague
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41
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42
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Affiliation(s)
- W Zacharias
- Department of Biochemistry, School of Medicine, University of Alabama, Birmingham 35294-0005
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Lee W, Krishna N. Influence of conformational exchange on the 2D NOESY spectra of biomolecules existing in multiple conformations. ACTA ACUST UNITED AC 1992. [DOI: 10.1016/0022-2364(92)90107-i] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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44
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Abstract
The telomeres of most eukaryotes contain a repeating G-rich sequence with the consensus d(T/A)1-4G1-8, of which 12-16 bases form a 3' single-strand overhang beyond the telomeric duplex. It has been proposed that these G-rich oligonucleotides associate to form four-stranded structures from one, two or four individual strands and that these structures may be relevant in vivo. The proposed structures contain Hoogsteen base-paired G-quartets, precedent for which has been in the literature for many years. Here we use 1H NMR spectroscopy to study the conformations of the DNA oligonucleotides d(G4T4G4) (Oxy-1.5) and d(G4T4G4T4G4T4G4) (Oxy-3.5) which contain the Oxytricha telomere repeat (T4G4). We find that these molecules fold to form a symmetrical bimolecular and an intramolecular quadruplex, respectively. Both structures have four G-quartets formed from nucleotides that are alternately syn and anti along each strand. This arrangement differs from earlier models in which the strands are alternately all syn or all anti. The T4 loops in Oxy-1.5 are on opposite ends of the quadruplex and loop diagonally across the G-quartet, resulting in adjacent strands being alternately parallel and antiparallel.
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Affiliation(s)
- F W Smith
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90024
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45
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Affiliation(s)
- J Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90024
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46
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47
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Weber J, Wokaun A. Two-dimensional NMR studies of the conformational B → Z transition in the oligodeoxynucleotides d(CG) 8and d(m 5CG) 8. Mol Phys 1991. [DOI: 10.1080/00268979100102241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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48
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Gilbert DE, Feigon J. The DNA sequence at echinomycin binding sites determines the structural changes induced by drug binding: NMR studies of echinomycin binding to [d(ACGTACGT)]2 and [d(TCGATCGA)]2. Biochemistry 1991; 30:2483-94. [PMID: 2001374 DOI: 10.1021/bi00223a027] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The complexes formed between the cyclic octadepsipeptide antibiotic echinomycin and the two DNA octamers [d(ACGTACGT)]2 and [d(TCGATCGA)]2 have been investigated by using one- and two-dimensional proton NMR spectroscopy techniques. The results obtained for the two complexes are compared to each other, to the crystal structures of related DNA-echinomycin complexes, and to enzymatic and chemical footprinting results. In the saturated complexes, two echinomycin molecules bind to each octamer by bisintercalation of the quinoxaline moieties on either side of each CpG step. Binding of echinomycin to the octamer [d(ACGTACGT)]2 is cooperative so that only the two-drug complex is observed at lower drug-DNA ratios, but binding to [d(TCGATCGA)]2 is not cooperative. At low temperatures, both the internal and terminal A.T base pairs adjacent to the binding site in the [d(ACGTACGT)]2-2 echinomycin complex are Hoogsteen base paired (Gilbert et al., 1989) as observed in related crystal structures. However, as the temperature is raised, the internal A.T Hoogsteen base pairs are destabilized and are observed to be exchanging between the Hoogsteen base-paired and an open (or Watson-Crick base-paired) state. In contrast, in the [d(TCGATCGA)]2-2 echinomycin complex, no A.T Hoogsteen base pairs are observed, the internal A.T base pairs appear to be stabilized by drug binding, and the structure of the complex does not change significantly from 0 to 45 degrees C. Thus, the structure and stability of the DNA in echinomycin-DNA complexes depends on the sequence at and adjacent to the binding site. While we conclude that no single structural change in the DNA can explain all of the footprinting results, unwinding of the DNA helix in the drug-DNA complexes appears to be an important factor while Hoogsteen base pair formation does not.
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Affiliation(s)
- D E Gilbert
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90024
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49
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Abstract
Left-handed double-helical Z-RNA has been studied using the ribohexanucleotide pentaphosphate r(CpGpCpGpCpG). One-dimensional and two-dimensional proton nmr experiments were used to probe the structural details of the left-handed helix in concentrated sodium perchlorate solution. In 1M NaClO4 the RNA adopts the normal A-form double helix, and in 6M NaClO4 it is nearly all in the Z form. In 4M NaClO4 it exists as nearly equal parts of A form and Z form. Resonances corresponding to both A and Z form appear in the nmr spectrum, indicating that the duplex exchanges slowly between forms. Spin-spin coupling constants between protons in the ribose rings were used to determine the sugar-pucker conformations of the individual nucleotides. Quantitative nuclear Overhauser experiments were used to determine proton-proton distances within the nucleoside, and from these distances values for the glycosidic torsion angle were determined. The results show that the cytidines adopt C2'-endo sugar puckers (S type) with pseudo-rotation phase values (P) of approximately 165 degrees. The bases are in the anti conformation, with chi values of approximately -140 degrees. The internal guanosines adopt C3'-endo sugar puckers (N type) with P approximately 18 degrees, while the 3'-terminal guanosine ribose exists in an equilibrium between S- and N-type conformations. All three guanosine bases adopt the syn conformation, with chi approximately 70 degrees. The results indicate that the solution structure of Z-RNA is very similar to that of Z-DNA.
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Affiliation(s)
- P W Davis
- Department of Chemistry, University of California, Berkeley 94720
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Structure Determination via Complete Relaxation Matrix Analysis (CORMA) of Two-Dimensional Nuclear Overhauser Effect Spectra. ACTA ACUST UNITED AC 1990. [DOI: 10.1007/978-1-4615-6549-9_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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