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Mlýnský V, Kührová P, Stadlbauer P, Krepl M, Otyepka M, Banáš P, Šponer J. Simple Adjustment of Intranucleotide Base-Phosphate Interaction in the OL3 AMBER Force Field Improves RNA Simulations. J Chem Theory Comput 2023; 19:8423-8433. [PMID: 37944118 PMCID: PMC10687871 DOI: 10.1021/acs.jctc.3c00990] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
Molecular dynamics (MD) simulations represent an established tool to study RNA molecules. The outcome of MD studies depends, however, on the quality of the force field (ff). Here we suggest a correction for the widely used AMBER OL3 ff by adding a simple adjustment of the nonbonded parameters. The reparameterization of the Lennard-Jones potential for the -H8···O5'- and -H6···O5'- atom pairs addresses an intranucleotide steric clash occurring in the type 0 base-phosphate interaction (0BPh). The nonbonded fix (NBfix) modification of 0BPh interactions (NBfix0BPh modification) was tuned via a reweighting approach and subsequently tested using an extensive set of standard and enhanced sampling simulations of both unstructured and folded RNA motifs. The modification corrects minor but visible intranucleotide clash for the anti nucleobase conformation. We observed that structural ensembles of small RNA benchmark motifs simulated with the NBfix0BPh modification provide better agreement with experiments. No side effects of the modification were observed in standard simulations of larger structured RNA motifs. We suggest that the combination of OL3 RNA ff and NBfix0BPh modification is a viable option to improve RNA MD simulations.
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Affiliation(s)
- Vojtěch Mlýnský
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, Brno 612 00, Czech Republic
| | - Petra Kührová
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, Brno 612 00, Czech Republic
- Czech
Advanced Technology and Research Institute, CATRIN, Křížkovského 511/8, Olomouc 779 00, Czech Republic
| | - Petr Stadlbauer
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, Brno 612 00, Czech Republic
- Czech
Advanced Technology and Research Institute, CATRIN, Křížkovského 511/8, Olomouc 779 00, Czech Republic
| | - Miroslav Krepl
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, Brno 612 00, Czech Republic
- Czech
Advanced Technology and Research Institute, CATRIN, Křížkovského 511/8, Olomouc 779 00, Czech Republic
| | - Michal Otyepka
- Czech
Advanced Technology and Research Institute, CATRIN, Křížkovského 511/8, Olomouc 779 00, Czech Republic
- IT4Innovations, VSB−Technical University of Ostrava, 17. listopadu 2172/15, Ostrava-Poruba 708 00, Czech Republic
| | - Pavel Banáš
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, Brno 612 00, Czech Republic
- Czech
Advanced Technology and Research Institute, CATRIN, Křížkovského 511/8, Olomouc 779 00, Czech Republic
- IT4Innovations, VSB−Technical University of Ostrava, 17. listopadu 2172/15, Ostrava-Poruba 708 00, Czech Republic
| | - Jiří Šponer
- Institute
of Biophysics of the Czech Academy of Sciences, Královopolská 135, Brno 612 00, Czech Republic
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2
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Mlýnský V, Janeček M, Kührová P, Fröhlking T, Otyepka M, Bussi G, Banáš P, Šponer J. Toward Convergence in Folding Simulations of RNA Tetraloops: Comparison of Enhanced Sampling Techniques and Effects of Force Field Modifications. J Chem Theory Comput 2022; 18:2642-2656. [PMID: 35363478 DOI: 10.1021/acs.jctc.1c01222] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atomistic molecular dynamics simulations represent an established technique for investigation of RNA structural dynamics. Despite continuous development, contemporary RNA simulations still suffer from suboptimal accuracy of empirical potentials (force fields, ffs) and sampling limitations. Development of efficient enhanced sampling techniques is important for two reasons. First, they allow us to overcome the sampling limitations, and second, they can be used to quantify ff imbalances provided they reach a sufficient convergence. Here, we study two RNA tetraloops (TLs), namely the GAGA and UUCG motifs. We perform extensive folding simulations and calculate folding free energies (ΔGfold°) with the aim to compare different enhanced sampling techniques and to test several modifications of the nonbonded terms extending the AMBER OL3 RNA ff. We demonstrate that replica-exchange solute tempering (REST2) simulations with 12-16 replicas do not show any sign of convergence even when extended to a timescale of 120 μs per replica. However, the combination of REST2 with well-tempered metadynamics (ST-MetaD) achieves good convergence on a timescale of 5-10 μs per replica, improving the sampling efficiency by at least 2 orders of magnitude. Effects of ff modifications on ΔGfold° energies were initially explored by the reweighting approach and then validated by new simulations. We tested several manually prepared variants of the gHBfix potential which improve stability of the native state of both TLs by ∼2 kcal/mol. This is sufficient to conveniently stabilize the folded GAGA TL while the UUCG TL still remains under-stabilized. Appropriate adjustment of van der Waals parameters for C-H···O5' base-phosphate interaction may further stabilize the native states of both TLs by ∼0.6 kcal/mol.
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Affiliation(s)
- Vojtěch Mlýnský
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Michal Janeček
- Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46 Olomouc, Czech Republic
| | - Petra Kührová
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
| | - Thorben Fröhlking
- Scuola Internazionale Superiore di Studi Avanzati, SISSA, via Bonomea 265, 34136 Trieste, Italy
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic.,IT4Innovations, VSB─Technical University of Ostrava, 17. listopadu 2172/15, 708 00 Ostrava-Poruba, Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati, SISSA, via Bonomea 265, 34136 Trieste, Italy
| | - Pavel Banáš
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute (CATRIN), Palacký University Olomouc, Šlechtitelů 27, 779 00 Olomouc, Czech Republic
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3
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Mráziková K, Mlýnský V, Kührová P, Pokorná P, Kruse H, Krepl M, Otyepka M, Banáš P, Šponer J. UUCG RNA Tetraloop as a Formidable Force-Field Challenge for MD Simulations. J Chem Theory Comput 2020; 16:7601-7617. [PMID: 33215915 DOI: 10.1021/acs.jctc.0c00801] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Explicit solvent atomistic molecular dynamics (MD) simulations represent an established technique to study structural dynamics of RNA molecules and an important complement for diverse experimental methods. However, performance of molecular mechanical (MM) force fields (ff's) remains far from satisfactory even after decades of development, as apparent from a problematic structural description of some important RNA motifs. Actually, some of the smallest RNA molecules belong to the most challenging systems for MD simulations and, among them, the UUCG tetraloop is saliently difficult. We report a detailed analysis of UUCG MD simulations, depicting the sequence of events leading to the loss of the UUCG native state during MD simulations. The total amount of MD simulation data analyzed in this work is close to 1.3 ms. We identify molecular interactions, backbone conformations, and substates that are involved in the process. Then, we unravel specific ff deficiencies using diverse quantum mechanical/molecular mechanical (QM/MM) and QM calculations. Comparison between the MM and QM methods shows discrepancies in the description of the 5'-flanking phosphate moiety and both signature sugar-base interactions. Our work indicates that poor behavior of the UUCG tetraloop in simulations is a complex issue that cannot be attributed to one dominant and straightforwardly correctable factor. Instead, there is a concerted effect of multiple ff inaccuracies that are coupled and amplifying each other. We attempted to improve the simulation behavior by some carefully tailored interventions, but the results were still far from satisfactory, underlying the difficulties in development of accurate nucleic acid ff's.
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Affiliation(s)
- Klaudia Mráziková
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Vojtěch Mlýnský
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Petra Kührová
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Pavlína Pokorná
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Holger Kruse
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Michal Otyepka
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Pavel Banáš
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic.,Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
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4
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Kührová P, Mlýnský V, Zgarbová M, Krepl M, Bussi G, Best RB, Otyepka M, Šponer J, Banáš P. Improving the Performance of the Amber RNA Force Field by Tuning the Hydrogen-Bonding Interactions. J Chem Theory Comput 2019; 15:3288-3305. [PMID: 30896943 PMCID: PMC7491206 DOI: 10.1021/acs.jctc.8b00955] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecular dynamics (MD) simulations became a leading tool for investigation of structural dynamics of nucleic acids. Despite recent efforts to improve the empirical potentials (force fields, ffs), RNA ffs have persisting deficiencies, which hamper their utilization in quantitatively accurate simulations. Previous studies have shown that at least two salient problems contribute to difficulties in the description of free-energy landscapes of small RNA motifs: (i) excessive stabilization of the unfolded single-stranded RNA ensemble by intramolecular base-phosphate and sugar-phosphate interactions and (ii) destabilization of the native folded state by underestimation of stability of base pairing. Here, we introduce a general ff term (gHBfix) that can selectively fine-tune nonbonding interaction terms in RNA ffs, in particular, the H bonds. The gHBfix potential affects the pairwise interactions between all possible pairs of the specific atom types, while all other interactions remain intact; i.e., it is not a structure-based model. In order to probe the ability of the gHBfix potential to refine the ff nonbonded terms, we performed an extensive set of folding simulations of RNA tetranucleotides and tetraloops. On the basis of these data, we propose particular gHBfix parameters to modify the AMBER RNA ff. The suggested parametrization significantly improves the agreement between experimental data and the simulation conformational ensembles, although our current ff version still remains far from being flawless. While attempts to tune the RNA ffs by conventional reparametrizations of dihedral potentials or nonbonded terms can lead to major undesired side effects, as we demonstrate for some recently published ffs, gHBfix has a clear promising potential to improve the ff performance while avoiding introduction of major new imbalances.
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Affiliation(s)
- Petra Kührová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Vojtěch Mlýnský
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Marie Zgarbová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Miroslav Krepl
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati, SISSA, via Bonomea 265, 34136 Trieste, Italy
| | - Robert B. Best
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
| | - Jiří Šponer
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University, tř. 17 listopadu 12, 771 46, Olomouc, Czech Republic
- Institute of Biophysics of the Czech Academy of Sciences, Královopolská 135, 612 65 Brno, Czech Republic
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5
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Kadeřávek P, Zapletal V, Fiala R, Srb P, Padrta P, Přecechtělová JP, Šoltésová M, Kowalewski J, Widmalm G, Chmelík J, Sklenář V, Žídek L. Spectral density mapping at multiple magnetic fields suitable for (13)C NMR relaxation studies. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 266:23-40. [PMID: 27003380 DOI: 10.1016/j.jmr.2016.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 02/20/2016] [Accepted: 02/23/2016] [Indexed: 06/05/2023]
Abstract
Standard spectral density mapping protocols, well suited for the analysis of (15)N relaxation rates, introduce significant systematic errors when applied to (13)C relaxation data, especially if the dynamics is dominated by motions with short correlation times (small molecules, dynamic residues of macromolecules). A possibility to improve the accuracy by employing cross-correlated relaxation rates and on measurements taken at several magnetic fields has been examined. A suite of protocols for analyzing such data has been developed and their performance tested. Applicability of the proposed protocols is documented in two case studies, spectral density mapping of a uniformly labeled RNA hairpin and of a selectively labeled disaccharide exhibiting highly anisotropic tumbling. Combination of auto- and cross-correlated relaxation data acquired at three magnetic fields was applied in the former case in order to separate effects of fast motions and conformational or chemical exchange. An approach using auto-correlated relaxation rates acquired at five magnetic fields, applicable to anisotropically moving molecules, was used in the latter case. The results were compared with a more advanced analysis of data obtained by interpolation of auto-correlated relaxation rates measured at seven magnetic fields, and with the spectral density mapping of cross-correlated relaxation rates. The results showed that sufficiently accurate values of auto- and cross-correlated spectral density functions at zero and (13)C frequencies can be obtained from data acquired at three magnetic fields for uniformly (13)C-labeled molecules with a moderate anisotropy of the rotational diffusion tensor. Analysis of auto-correlated relaxation rates at five magnetic fields represents an alternative for molecules undergoing highly anisotropic motions.
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Affiliation(s)
- Pavel Kadeřávek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Institute of Biophysics of Academy of Sciences of the Czech Republic, Královopolská 135, CZ-612 65 Brno, Czech Republic.
| | - Vojtěch Zapletal
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
| | - Radovan Fiala
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
| | - Pavel Srb
- Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
| | - Petr Padrta
- Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
| | | | - Mária Šoltésová
- Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, CZ-180 00 Prague, Czech Republic.
| | - Jozef Kowalewski
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
| | - Josef Chmelík
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ-142 00 Prague 4 - Krč, Czech Republic.
| | - Vladimír Sklenář
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
| | - Lukáš Žídek
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic; Central European Institute of Technology, Masaryk University, Kamenice 5, CZ-625 00 Brno, Czech Republic.
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6
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Tamm T, Suurväli J, Lucchesi J, Olspert A, Truve E. Stem-loop structure of Cocksfoot mottle virus RNA is indispensable for programmed -1 ribosomal frameshifting. Virus Res 2009; 146:73-80. [PMID: 19748532 PMCID: PMC7114514 DOI: 10.1016/j.virusres.2009.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 08/08/2009] [Accepted: 09/02/2009] [Indexed: 10/29/2022]
Abstract
The -1 programmed ribosomal frameshifting (-1 PRF) mechanism utilized by many viruses is dependent on a heptanucleotide slippery sequence and a downstream secondary structure element. In the current study, the RNA structure downstream from the slippery site of cocksfoot mottle sobemovirus (CfMV) was proven to be a 12bp stem-loop with a single bulge and a tetranucleotide loop. Several deletion and insertion mutants with altered stem-loop structures were tested in wheat germ extract (WGE) for frameshifting efficiency. The impact of the same mutations on virus infectivity was tested in oat plants. Mutations shortening or destabilizing the stem region reduced significantly but did not abolish -1 PRF in WGE. The same mutations proved to be deleterious for virus infection. However, extending the loop region to seven nucleotides had no significant effect on frameshifting efficiency in WGE and did not hamper virus replication in infected leaves. This is the first report about the experimentally proven RNA secondary structure directing -1 PRF of sobemoviruses.
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Affiliation(s)
- Tiina Tamm
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23, Tartu 51010, Estonia
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7
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Reipa V, Niaura G, Atha DH. Conformational analysis of the telomerase RNA pseudoknot hairpin by Raman spectroscopy. RNA (NEW YORK, N.Y.) 2007; 13:108-15. [PMID: 17119100 PMCID: PMC1705750 DOI: 10.1261/rna.182607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Accepted: 09/26/2006] [Indexed: 05/12/2023]
Abstract
We have measured the temperature-dependent Raman spectra of two 30-mer ribonucleotides that represent the wild-type (WT) and dyskeratosis congenita (DKC) mutant (MT) GC (107-108) --> AG structures of the pseudoknot hairpin region of human telomerase RNA. We have used these structures, previously characterized by UV-melting and NMR, as a model system for our Raman investigation. We observe that Raman hypochromism of vibrational bands, previously assigned to specific bases or conformational RNA markers, reflect temperature-dependent alterations in the pentaloop and stem structures of these two oligonucleotides. We also observe that the intense nu(s)(O-P-O) band at 812 cm(-1) indicates the presence of A-form backbone structure at relatively low temperatures in both the WT and MT RNA sequences. The mutation induces a decrease in the intensity of the uridine (rU) band at 1244 cm(-1) associated with C2'-endo/anti ribose conformation in the pentaloop. Two transition temperatures (T(m) ) were determined from the analysis of Raman difference intensity-temperature profiles of the 1256 cm(-1) band, which is associated with vibrations of cytidine (rC) residues, in particular, the C2'-endo/anti ribose conformation (T(m) 1 = 23.6 +/- 1.6 degrees C for WT and 19.7 +/- 2.8 degrees C for MT; T(m) 2 = 68.9 +/- 1.8 degrees C for WT and 70.9 +/- 1.1 degrees C for MT). From these results we can conclude that the DKC mutant 30-mer exhibits a lower stability in the pentaloop region and a slightly higher stability in the stem region than the WT 30-mer. This demonstrates that Raman bands, previously assigned to specific bases or conformational RNA markers, can be used to probe local structural features of the telomerase pseudoknot hairpin sequence.
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Affiliation(s)
- Vytas Reipa
- Biochemical Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8311, USA
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8
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Hernández B, Baumruk V, Gouyette C, Ghomi M. Thermal stability, structural features, and B-to-Z transition in DNA tetraloop hairpins as determined by optical spectroscopy in d(CG)(3)T(4)(CG)(3) and d(CG)(3)A(4)(CG)(3) oligodeoxynucleotides. Biopolymers 2005; 78:21-34. [PMID: 15690428 DOI: 10.1002/bip.20246] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
NMR and CD data have previously shown the formation of the T(4) tetraloop hairpin in aqueous solutions, as well as the possibility of the B-to-Z transition in its stem in high salt concentration conditions. It has been shown that the stem B-to-Z transition in T(4) hairpins leads to S (south)- to N (north)-type conformational changes in the loop sugars, as well as anti to syn orientations in the loop bases. In this article, we have compared by means of UV absorption, CD, Raman, and Fourier transform infrared (FTIR), the thermodynamic and structural properties of the T(4) and A(4) tetraloop hairpins formed in 5'-d(CGCGCG-TTTT-CGCGCG)-3' and 5'-d(CGCGCG-AAAA-CGCGCG)-3', respectively. In presence of 5M NaClO(4), a complete B-to-Z transition of the stems is first proved by CD spectra. UV melting profiles are consistent with a higher thermal stability of the T(4) hairpin compared to the A(4) hairpin. Order-to-disorder transition of both hairpins has also been analyzed by means of Raman spectra recorded as a function of temperature. A clear Z-to-B transition of the stem has been confirmed in the T(4) hairpin, and not in the A(4) hairpin. With a right-handed stem, Raman and FTIR spectra have confirmed the C2'-endo/anti conformation for all the T(4) loop nucleosides. With a left-handed stem, a part of the T(4) loop sugars adopt a N-type (C3'-endo) conformation, and the C3'-endo/syn conformation seems to be the preferred one for the dA residues involved in the A(4) tetraloop.
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Affiliation(s)
- Belén Hernández
- UMR CNRS 7033, BioMoCeTi, Université Pierre et Marie Curie, 75252 Paris cedex 05, France
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9
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Proctor DJ, Ma H, Kierzek E, Kierzek R, Gruebele M, Bevilacqua PC. Folding thermodynamics and kinetics of YNMG RNA hairpins: specific incorporation of 8-bromoguanosine leads to stabilization by enhancement of the folding rate. Biochemistry 2005; 43:14004-14. [PMID: 15518549 DOI: 10.1021/bi048213e] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modified nucleotides allow fundamental energetic and kinetic properties of nucleic acids to be probed. Here, we demonstrate that an RNA hairpin containing the nucleotide analogue 8-bromoguanosine (8BrG or G), gcUUCGgc, has enhanced stability relative to the unmodified hairpin, with DeltaDeltaG(37)(degrees)= -0.69 +/- 0.15 kcal mol(-1) and DeltaT(M) = +6.8 +/- 1.4 degrees C. NMR spectroscopic data suggest that the enhanced stability of gcUUCGgc does not arise from the native state; laser temperature-jump experiments support this notion, as gcUUCGgc and gcUUCGgc have similar unfolding rate constants, but the folding rate constant of gcUUCGgc is 4.1-fold faster at 37.5 degrees C and 2.8-fold faster under isoenergetic conditions. On the basis of these findings, we propose that 8BrG reduces the conformational entropy of the denatured state, resulting in an accelerated conformational search for the native state and enhanced stability.
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Affiliation(s)
- David J Proctor
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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10
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Hernández B, Baumruk V, Leulliot N, Gouyette C, Huynh-Dinh T, Ghomi M. Thermodynamic and structural features of ultrastable DNA and RNA hairpins. J Mol Struct 2003. [DOI: 10.1016/s0022-2860(02)00627-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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11
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Yuan Y, Kerwood DJ, Paoletti AC, Shubsda MF, Borer PN. Stem of SL1 RNA in HIV-1: structure and nucleocapsid protein binding for a 1 x 3 internal loop. Biochemistry 2003; 42:5259-69. [PMID: 12731867 DOI: 10.1021/bi034084a] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 5'-leader of HIV-1 RNA controls many viral functions. Nucleocapsid (NC) domains of gag-precursor proteins select genomic RNA for packaging by binding several sites in the leader. One is likely to be a stem defect in SL1 that can adopt either a 1 x 3 internal loop, SL1i (including G247, A271, G272, G273) or a 1 x 1 internal loop (G247 x G273) near a two-base bulge (A269-G270). It is likely that these two conformations are both present and exchange readily. A 23mer RNA construct described here models SL1i and cannot slip into the alternate form. It forms a 1:1 complex with NCp7, which interacts most strongly at G247 and G272 (K(d) = 140 nM). This demonstrates that a linear G-X-G sequence is unnecessary for high-affinity binding. The NMR-based structure shows an easily broken G247:A271 base pair. G247 stacks on both of its immediate neighbors and A271 on its 5'-neighbor; G272 and G273 are partially ordered. A bend in the helix axis between the SL1 stems on either side of the internal loop is probable. An important step in maturation of the virus is the transition from an apical loop-loop interaction to a dimer involving intermolecular interactions along the full length of SL1. A bend in the stem may be important in relieving strain and ensuring that the strands do not become entangled during the transition. A stem defect with special affinity for NCp7 may accelerate the rate of the dimer transformation. This complex could become an important target for anti-HIV drug development, where a drug could exert its action near a high-energy intermediate on the pathway for maturation of the dimer.
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MESH Headings
- Base Sequence
- Capsid/chemistry
- Capsid/metabolism
- Capsid Proteins
- DNA, Viral/metabolism
- Dimerization
- Gene Products, gag/chemistry
- Gene Products, gag/metabolism
- Genome, Viral
- HIV Infections/virology
- HIV-1/genetics
- Humans
- Models, Structural
- Molecular Sequence Data
- Nuclear Magnetic Resonance, Biomolecular
- Nucleic Acid Conformation
- RNA, Spliced Leader/chemistry
- RNA, Viral/chemistry
- RNA, Viral/metabolism
- Viral Proteins
- Virus Assembly
- gag Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- YiQiong Yuan
- Department of Chemistry, Graduate Program in Structural Biology, Biochemistry, and Biophysics, Syracuse University, Syracuse, New York 13244-4100, USA
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12
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Comolli LR, Ulyanov NB, Soto AM, Marky LA, James TL, Gmeiner WH. NMR structure of the 3' stem-loop from human U4 snRNA. Nucleic Acids Res 2002; 30:4371-9. [PMID: 12384583 PMCID: PMC137124 DOI: 10.1093/nar/gkf560] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The NMR structure of the 3' stem-loop (3'SL) from human U4 snRNA was determined to gain insight into the structural basis for conservation of this stem-loop sequence from vertebrates. 3'SL sequences from human, rat, mouse and chicken U4 snRNA each consist of a 7 bp stem capped by a UACG tetraloop. No high resolution structure has previously been reported for a UACG tetraloop. The UACG tetraloop portion of the 3'SL was especially well defined by the NMR data, with a total of 92 NOE-derived restraints (about 15 per residue), including 48 inter-residue restraints (about 8 per residue) for the tetraloop and closing C-G base pair. Distance restraints were derived from NOESY spectra using MARDIGRAS with random error analysis. Refinement of the 20mer RNA hairpin structure was carried out using the programs DYANA and miniCarlo. In the UACG tetraloop, U and G formed a base pair stabilized by two hydrogen bonds, one between the 2'-hydroxyl proton of U and carbonyl oxygen of G, another between the imino proton of G and carbonyl oxygen O2 of U. In addition, the amino group of C formed a hydrogen bond with the phosphate oxygen of A. G adopted a syn orientation about the glycosidic bond, while the sugar puckers of A and C were either C2'-endo or flexible. The conformation of the UACG tetraloop was, overall, similar to that previously reported for UUCG tetraloops, another member of the UNCG class of tetraloops. The presence of an A, rather than a U, at the variable position, however, presents a distinct surface for interaction of the 3'SL tetraloop with either RNA or protein residues that may stabilize interactions important for active spliceosome formation. Such tertiary interactions may explain the conservation of the UACG tetraloop motif in 3'SL sequences from U4 snRNA in vertebrates.
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Affiliation(s)
- Luis R Comolli
- Department of Pharmaceutical Chemistry, University of California at San Francisco, San Francisco, CA 94143, USA
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13
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Baumruk V, Gouyette C, Huynh-Dinh T, Sun JS, Ghomi M. Comparison between CUUG and UUCG tetraloops: thermodynamic stability and structural features analyzed by UV absorption and vibrational spectroscopy. Nucleic Acids Res 2001; 29:4089-96. [PMID: 11574692 PMCID: PMC60239 DOI: 10.1093/nar/29.19.4089] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2001] [Revised: 08/07/2001] [Accepted: 08/07/2001] [Indexed: 11/14/2022] Open
Abstract
CUUG loop is one of the most frequently occurring tetraloops in bacterial 16S rRNA. This tetraloop has a high thermodynamic stability as proved by previous UV absorption and NMR experiments. Here, we present our results concerning the thermodynamic and structural features of the 10mer 5'-r(GCG-CUUG-CGC)-3', forming a highly stable CUUG tetraloop hairpin in aqueous solution, by means of several optical techniques (UV and FT-IR absorption, Raman scattering). UV melting profile of this decamer provides a high melting temperature (60.7 degrees C). A set of Raman spectra recorded at different temperatures allowed us to analyze the order-to-disorder (hairpin-to-random coil) transition. Assignment of vibrational markers led us to confirm the particular nucleoside conformation, and to get information on the base stacking and base pairing in the hairpin structure. Moreover, comparison of the data obtained from two highly stable CUUG and UUCG tetraloops containing the same nucleotides but in a different order permitted an overall discussion of their structural features on the basis of Raman marker evidences.
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Affiliation(s)
- V Baumruk
- Institute of Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
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14
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Gaigeot MP, Leulliot N, Ghomi M, Jobic H, Coulombeau C, Bouloussa O. Analysis of the structural and vibrational properties of RNA building blocks by means of neutron inelastic scattering and density functional theory calculations. Chem Phys 2000. [DOI: 10.1016/s0301-0104(00)00224-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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15
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Leulliot N, Ghomi M, Scalmani G, Berthier G. Ground State Properties of the Nucleic Acid Constituents Studied by Density Functional Calculations. I. Conformational Features of Ribose, Dimethyl Phosphate, Uridine, Cytidine, 5‘-Methyl Phosphate−Uridine, and 3‘-Methyl Phosphate−Uridine. J Phys Chem A 1999. [DOI: 10.1021/jp9915634] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Abdelkafi M, Leulliot N, Baumruk V, Bednárová L, Turpin PY, Namane A, Gouyette C, Huynh-Dinh T, Ghomi M. Structural features of the UCCG and UGCG tetraloops in very short hairpins as evidenced by optical spectroscopy. Biochemistry 1998; 37:7878-84. [PMID: 9601049 DOI: 10.1021/bi980011t] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Structures of the UCCG and UGCG tetraloops formed in octamer ribonucleotidic hairpin sequences, i.e., 5'-r[GC(UCCG)GC]-3' and 5'-r[GC(UGCG)GC]-3', have been studied in aqueous solution by methods of optical spectroscopy. UV absorption melting profiles of these short hairpins, containing only two closing GC base pairs in the stem, are consistent with a monophasic, completely reversible order-to-disorder transition and clearly confirm their unusual structural stability (with Tm congruent with 50 degrees C). To establish structural characteristics of these tetraloops, Raman and FTIR spectroscopies have been used and vibrational conformation markers arising from the phosphate backbone and various nucleosides have been analyzed. They have been assigned on the basis of known unambiguous vibrational markers established for DNA and RNA chains. Surprisingly, they are easily transferable to short oligonucleotidic sequences. Intensities and wavenumbers of these conformation markers have been monitored in the 0-70 degrees C temperature range, i.e., in going from an ordered to a disordered structure. The main structural features of the UCCG and UGCG tetraloops are similar to those previously found in the UUCG and UACG tetraloops by means of NMR and vibrational spectroscopies, except those of the second nucleosides of the tetraloops (rC and rG, respectively) which adopt a 3'-endo/anti rather than a 2'-endo/anti conformation.
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Affiliation(s)
- M Abdelkafi
- Laboratoire de Physicochimie Biomoléculaire et Cellulaire, URA CNRS 2056, Université Pierre et Marie Curie, Paris, France
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