1
|
Meredith RJ, Carmichael I, Woods RJ, Serianni AS. MA'AT Analysis: Probability Distributions of Molecular Torsion Angles in Solution from NMR Spectroscopy. Acc Chem Res 2023; 56:2313-2328. [PMID: 37566472 DOI: 10.1021/acs.accounts.3c00286] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
ConspectusMonosaccharides adopt multiple conformations in solution, and this structural complexity increases significantly when they are assembled into oligosaccharides and polysaccharides. Characterization of the conformational properties of saccharides in solution by NMR spectroscopy has been hampered by several complicating factors, including difficulty interpreting spectra because of significant signal overlap, population averaging of NMR parameters, and unique properties of the spectra that make accurate measurements of NMR parameters prone to error (e.g., non-first-order effects on J-couplings). Current conformational assignments rely heavily on theoretical calculations, especially molecular dynamics (MD) simulations, to interpret the experimental NMR parameters. While these studies assert that the available experimental data fit the calculated models well, a lack of independent experimental validation of the force fields from which MD models are derived and an inability to test all possible models that might be compatible with the experimental data in an unbiased manner make the approach less than ideal.NMR spin couplings or J-couplings have been used as structure constraints in organic and other types of molecules for more than six decades. The dihedral angle dependence of vicinal (three-bond) 1H-1H spin couplings (3JHH) first described by Karplus led to an explosion of applications for a wide range of conformational problems. Other vicinal J-couplings (e.g., 3JCCOP, 3JHCOP, and 3JCOCH) have been found to exhibit similar dihedral angle dependencies. 3J values have been used to assign the preferred conformation in molecules that are conformationally homogeneous. However, many molecules, particularly those in biological systems, are conformationally flexible, which complicates structural interpretations of J values in solution. Three-state staggered models are often assumed in order to deconvolute the conformationally averaged J values into conformer populations. While widely applied, this approach assumes highly idealized models of molecular torsion angles that are likely to be poor representations of those found in solution. In addition, this treatment often gives negative populations and neglects the presence of librational averaging of molecular torsion angles.Recent work in this research group has focused on the development of a hybrid experimental-computational method, MA'AT analysis, that provides probability distributions of molecular torsion angles in solution that can be superimposed on those obtained by MD. Ensembles of redundant NMR spin couplings, including 3J (vicinal), 2J (geminal), and sometimes 1J (direct) values, are used in conjunction with circular statistics to provide single- and multistate models of these angles. MA'AT analysis provides accurate mean torsion angles and circular standard deviations (CSDs) of each mean angle that describe the librational motion about the angle. Both conformational equilibria and dynamics are revealed by the method. In this Account, the salient features of MA'AT analysis are discussed, including some applications to conformational problems involving saccharides and peptides.
Collapse
Affiliation(s)
- Reagan J Meredith
- Texas Biomedical Research Institute, San Antonio, Texas 78227, United States
| | | | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia 30602, United States
| | | |
Collapse
|
2
|
Meredith RJ, McGurn M, Euell C, Rutkowski P, Cook E, Carmichael I, Serianni AS. MA'AT Analysis of Aldofuranosyl Rings: Unbiased Modeling of Conformational Equilibria and Dynamics in Solution. Biochemistry 2022; 61:239-251. [PMID: 35104120 DOI: 10.1021/acs.biochem.1c00630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
MA'AT analysis has been applied to methyl β-d-ribofuranoside (3) and methyl 2-deoxy-β-d-erythro-pentofuranoside (4) to demonstrate the ability of this new experimental method to determine multi-state conformational equilibria in solution. Density functional theory (DFT) was used to obtain parameterized equations for >20 NMR spin-coupling constants sensitive to furanose ring conformation in 3 and 4, and these equations were used in conjunction with experimental spin-couplings to produce unbiased MA'AT models of ring pseudorotation. These models describe two-state north-south conformational exchange consistent with results obtained from traditional treatments of more limited sets of NMR spin-couplings (e.g., PSEUROT). While PSEUROT, MA'AT, and aqueous molecular dynamics models yielded similar two-state models, MA'AT analysis gives more reliable results since significantly more experimental observables are employed compared to PSEUROT, and no assumptions are needed to render the fitting tractable. MA'AT models indicate a roughly equal distribution of north and south ring conformers of 4 in aqueous (2H2O) solution compared to ∼80% north forms for 3. Librational motion about the mean pseudorotation phase angles P of the preferred north and south conformers of 3 in solution is more constrained than that for 4. The greater rigidity of the β-ribo ring may be caused by synergistic stereoelectronic effects and/or noncovalent (e.g., hydrogen-bonding) interactions in solution that preferentially stabilize north forms of 3. MA'AT analysis of oligonucleotides and other furanose ring-containing biomolecules promises to improve current experimental models of sugar ring behavior in solution and help reveal context effects on ring conformation in more complex biologically important systems.
Collapse
Affiliation(s)
- Reagan J Meredith
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| | - Margaret McGurn
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| | - Christopher Euell
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| | - Peter Rutkowski
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| | - Evan Cook
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| | - Ian Carmichael
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| | - Anthony S Serianni
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana46556-5670, United States
| |
Collapse
|
3
|
Zgarbová M, Jurečka P, Šponer J, Otyepka M. A- to B-DNA Transition in AMBER Force Fields and Its Coupling to Sugar Pucker. J Chem Theory Comput 2017; 14:319-328. [DOI: 10.1021/acs.jctc.7b00926] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Marie Zgarbová
- Regional Centre of Advanced
Technologies and Materials, Department of Physical Chemistry, Faculty
of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - Petr Jurečka
- Regional Centre of Advanced
Technologies and Materials, Department of Physical Chemistry, Faculty
of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - Jiří Šponer
- Regional Centre of Advanced
Technologies and Materials, Department of Physical Chemistry, Faculty
of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced
Technologies and Materials, Department of Physical Chemistry, Faculty
of Science, Palacky University, 17. listopadu 12, 77146 Olomouc, Czech Republic
| |
Collapse
|
4
|
Pshetitsky Y, Eitan R, Verner G, Kohen A, Major DT. Improved Sugar Puckering Profiles for Nicotinamide Ribonucleoside for Hybrid QM/MM Simulations. J Chem Theory Comput 2016; 12:5179-5189. [PMID: 27490188 DOI: 10.1021/acs.jctc.6b00401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The coenzyme nicotinamide adenine dinucleotide (NAD+) and its reduced form (NADH) play ubiquitous roles as oxidizing and reducing agents in nature. The binding, and possibly the chemical redox step, of NAD+/NADH may be influenced by the cofactor conformational distribution and, in particular, by the ribose puckering of its nicotinamide-ribonucleoside (NR) moiety. In many hybrid quantum mechanics-molecular mechanics (QM/MM) studies of NAD+/NADH dependent enzymes, the QM region is treated by semiempirical (SE) methods. Recent work suggests that SE methods do not adequately describe the ring puckering in sugar molecules. In the present work we adopt an efficient and practical strategy to correct for this deficiency for NAD+/NADH. We have implemented a cost-effective correction to a SE Hamiltonian by adding a correction potential, which is defined as the difference between an accurate benchmark density functional theory (DFT) potential energy surface (PES) and the SE PES. In practice, this is implemented via a B-spline interpolation scheme for the grid-based potential energy difference surface. We find that the puckering population distributions obtained from free energy QM(SE)/MM simulations are in good agreement with DFT and in fair accord with experimental results. The corrected PES should facilitate a more accurate description of the ribose puckering in the NAD+/NADH cofactor in simulations of biological systems.
Collapse
Affiliation(s)
- Yaron Pshetitsky
- Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University , Ramat-Gan 52900, Israel
| | - Reuven Eitan
- Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University , Ramat-Gan 52900, Israel
| | - Gilit Verner
- Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University , Ramat-Gan 52900, Israel
| | - Amnon Kohen
- Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States
| | - Dan Thomas Major
- Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University , Ramat-Gan 52900, Israel
| |
Collapse
|
5
|
Duchardt E, Nilsson L, Schleucher J. Cytosine ribose flexibility in DNA: a combined NMR 13C spin relaxation and molecular dynamics simulation study. Nucleic Acids Res 2008; 36:4211-9. [PMID: 18579564 PMCID: PMC2475628 DOI: 10.1093/nar/gkn375] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Using (13)C spin relaxation NMR in combination with molecular dynamic (MD) simulations, we characterized internal motions within double-stranded DNA on the pico- to nano-second time scale. We found that the C-H vectors in all cytosine ribose moieties within the Dickerson-Drew dodecamer (5'-CGCGAATTCGCG-3') are subject to high amplitude motions, while the other nucleotides are essentially rigid. MD simulations showed that repuckering is a likely motional model for the cytosine ribose moiety. Repuckering occurs with a time constant of around 100 ps. Knowledge of DNA dynamics will contribute to our understanding of the recognition specificity of DNA-binding proteins such as cytosine methyltransferase.
Collapse
Affiliation(s)
- Elke Duchardt
- Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden.
| | | | | |
Collapse
|
6
|
Foloppe N, Nilsson L. Toward a full characterization of nucleic acid components in aqueous solution: simulations of nucleosides. J Phys Chem B 2007; 109:9119-31. [PMID: 16852085 DOI: 10.1021/jp044513u] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The eight nucleoside constituents of nucleic acids were simulated for 50 ns in explicit water with molecular dynamics. This provides equilibrium populations of the torsional degrees of freedom, their kinetics of interconversion, their couplings, and how they are influenced by water. This is important, given that a full and quantitative characterization of the nucleosides in aqueous solution by experimental means has been elusive, despite immense efforts in that direction. It is with the anti/syn equilibrium that the simulations are most complementary to experiment, by accessing directly the influence of the sugar type, sugar pucker, and base on the anti/syn populations. The glycosidic torsion distributions in the anti conformation are strongly affected by water and depart from the corresponding X-ray modal values and the associated energy minima in vacuo. Water also preferentially stabilizes some sugar conformations, showing that potential energies in vacuo are not sufficient to understand the nucleosides. Deoxythymidine (but not other pyrimidines) significantly populates the syn orientation. Guanine favors the syn orientation more than adenine. The ribose favors the syn orientation significantly more than the deoxyribose. The NORTH pucker coexists with the syn conformers. A hydrogen bond is frequently formed between the 5'-OH group and the syn bases, despite competition by water. The rate of the anti/syn transitions with purines is on the nanosecond time scale, confirming a long held assumption underpinning the interpretation of ultrasonic relaxation studies. Therefore, our knowledge of the structure and dynamics of nucleosides in solvent is only limited by the accuracy of the potential used to simulate them, and it is shown that such simulations provide a distinct and unique test of nucleic acid force fields. This confirmed that the widely distributed CHARMM27 force field is, overall, well-balanced with a particularly good representation of the ribose. Specific improvements, however, are suggested for the deoxyribose and torsion gamma.
Collapse
Affiliation(s)
- Nicolas Foloppe
- Center for Structural Biochemistry, Department of Biosciences, Karolinska Institutet, S-141 57 Huddinge, Sweden
| | | |
Collapse
|
7
|
Dixit SB, Beveridge DL, Case DA, Cheatham TE, Giudice E, Lankas F, Lavery R, Maddocks JH, Osman R, Sklenar H, Thayer KM, Varnai P. Molecular dynamics simulations of the 136 unique tetranucleotide sequences of DNA oligonucleotides. II: sequence context effects on the dynamical structures of the 10 unique dinucleotide steps. Biophys J 2005; 89:3721-40. [PMID: 16169978 PMCID: PMC1366942 DOI: 10.1529/biophysj.105.067397] [Citation(s) in RCA: 189] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Molecular dynamics (MD) simulations including water and counterions on B-DNA oligomers containing all 136 unique tetranucleotide basepair steps are reported. The objective is to obtain the calculated dynamical structure for at least two copies of each case, use the results to examine issues with regard to convergence and dynamical stability of MD on DNA, and determine the significance of sequence context effects on all unique dinucleotide steps. This information is essential to understand sequence effects on DNA structure and has implications on diverse problems in the structural biology of DNA. Calculations were carried out on the 136 cases embedded in 39 DNA oligomers with repeating tetranucleotide sequences, capped on both ends by GC pairs and each having a total length of 15 nucleotide pairs. All simulations were carried out using a well-defined state-of-the-art MD protocol, the AMBER suite of programs, and the parm94 force field. In a previous article (Beveridge et al. 2004. Biophysical Journal. 87:3799-3813), the research design, details of the simulation protocol, and informatics issues were described. Preliminary results from 15 ns MD trajectories were presented for the d(CpG) step in all 10 unique sequence contexts. The results indicated the sequence context effects to be small for this step, but revealed that MD on DNA at this length of trajectory is subject to surprisingly persistent cooperative transitions of the sugar-phosphate backbone torsion angles alpha and gamma. In this article, we report detailed analysis of the entire trajectory database and occurrence of various conformational substates and its impact on studies of context effects. The analysis reveals a possible direct correspondence between the sequence-dependent dynamical tendencies of DNA structure and the tendency to undergo transitions that "trap" them in nonstandard conformational substates. The difference in mean of the observed basepair step helicoidal parameter distribution with different flanking sequence sometimes differs by as much as one standard deviation, indicating that the extent of sequence effects could be significant. The observations reveal that the impact of a flexible dinucleotide such as CpG could extend beyond the immediate basepair neighbors. The results in general provide new insight into MD on DNA and the sequence-dependent dynamical structural characteristics of DNA.
Collapse
Affiliation(s)
- Surjit B Dixit
- Chemistry Department and Molecular Biophysics Program, Wesleyan University, Middletown, Connecticut 06459, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Evans FE, Levine RA. Conformational analysis of the 2'-deoxyribofuranose ring from proton-proton coupling constants: analysis of a nucleoside-carcinogen adduct formed from 2-acetylaminofluorene utilizing a three-state model. Biopolymers 1987; 26:1035-46. [PMID: 3620573 DOI: 10.1002/bip.360260704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
9
|
Lesyng B, Saenger W. Influence of the orientation of hydroxyl groups on the puckering modes of furanoid rings. Carbohydr Res 1984. [DOI: 10.1016/0008-6215(84)85197-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
10
|
Yoon CN, Kang YK, Jhon MS. Conformational study of trinucleoside tetraphosphate d(pCpGpCp): Transition of right-handed form to left-handed form. Biopolymers 1984. [DOI: 10.1002/bip.360230308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|