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Buduma K, A N, KVN S, J K, Chinde S, Domatti AK, Kumar Y, Grover P, Tiwari A, Khan F. Synthesis and bioactivity evaluation of eugenol hybrids obtained by Mannich and 1,3 dipolar cycloaddition reactions. J Heterocycl Chem 2021. [DOI: 10.1002/jhet.4331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Komuraiah Buduma
- Natural Product Chemistry Division CSIR‐Central Institute of Medicinal and Aromatic Plants, Research Centre Hyderabad India
| | - Niranjana A
- Natural Product Chemistry Division CSIR‐Central Institute of Medicinal and Aromatic Plants, Research Centre Hyderabad India
| | - Satya KVN
- Natural Product Chemistry Division CSIR‐Central Institute of Medicinal and Aromatic Plants, Research Centre Hyderabad India
| | - Kotesh J
- Natural Product Chemistry Division CSIR‐Central Institute of Medicinal and Aromatic Plants, Research Centre Hyderabad India
| | - Srinivas Chinde
- Toxicology Unit, Biology Division CSIR‐Indian Institute of Chemical Technology Hyderabad India
| | - Anand Kumar Domatti
- Medicinal Chemistry and Pharmacology Division CSIR‐Indian Institute of Chemical Technology Hyderabad India
| | - Yogesh Kumar
- Metabolic and Structural Biology Department CSIR‐Central Institute of Medicinal and Aromatic Plants Lucknow India
| | - Paramjit Grover
- Toxicology Unit, Biology Division CSIR‐Indian Institute of Chemical Technology Hyderabad India
| | - Ashok Tiwari
- Toxicology Unit, Biology Division CSIR‐Indian Institute of Chemical Technology Hyderabad India
| | - Feroz Khan
- Metabolic and Structural Biology Department CSIR‐Central Institute of Medicinal and Aromatic Plants Lucknow India
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Trausch JJ, Marcano-Velázquez JG, Matyjasik MM, Batey RT. Metal Ion-Mediated Nucleobase Recognition by the ZTP Riboswitch. ACTA ACUST UNITED AC 2015; 22:829-37. [PMID: 26144884 DOI: 10.1016/j.chembiol.2015.06.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 05/30/2015] [Accepted: 06/02/2015] [Indexed: 01/14/2023]
Abstract
The ZTP riboswitch is a widespread family of regulatory RNAs that upregulate de novo purine synthesis in response to increased intracellular levels of ZTP or ZMP. As an important intermediate in purine biosynthesis, ZMP also serves as a proxy for the concentration of N10-formyl-tetrahydrofolate, a key component of one-carbon metabolism. Here, we report the structure of the ZTP riboswitch bound to ZMP at a resolution of 1.80 Å. The RNA contains two subdomains brought together through a long-range pseudoknot further stabilized through helix-helix packing. ZMP is bound at the subdomain interface of the RNA through a set of interactions with the base, ribose sugar, and phosphate moieties of the ligand. Unique to nucleobase recognition by RNAs, the Z base is inner-sphere coordinated to a magnesium cation bound by two backbone phosphates. This interaction, along with steric hindrance by the backbone, imparts specificity over chemically similar compounds such as ATP/AMP.
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Affiliation(s)
- Jeremiah J Trausch
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Joan G Marcano-Velázquez
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Michal M Matyjasik
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA
| | - Robert T Batey
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Campus Box 596, Boulder, CO 80309-0596, USA.
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Mládek A, Banáš P, Jurečka P, Otyepka M, Zgarbová M, Šponer J. Energies and 2'-Hydroxyl Group Orientations of RNA Backbone Conformations. Benchmark CCSD(T)/CBS Database, Electronic Analysis, and Assessment of DFT Methods and MD Simulations. J Chem Theory Comput 2013; 10:463-80. [PMID: 26579924 DOI: 10.1021/ct400837p] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Sugar-phosphate backbone is an electronically complex molecular segment imparting RNA molecules high flexibility and architectonic heterogeneity necessary for their biological functions. The structural variability of RNA molecules is amplified by the presence of the 2'-hydroxyl group, capable of forming multitude of intra- and intermolecular interactions. Bioinformatics studies based on X-ray structure database revealed that RNA backbone samples at least 46 substates known as rotameric families. The present study provides a comprehensive analysis of RNA backbone conformational preferences and 2'-hydroxyl group orientations. First, we create a benchmark database of estimated CCSD(T)/CBS relative energies of all rotameric families and test performance of dispersion-corrected DFT-D3 methods and molecular mechanics in vacuum and in continuum solvent. The performance of the DFT-D3 methods is in general quite satisfactory. The B-LYP-D3 method provides the best trade-off between accuracy and computational demands. B3-LYP-D3 slightly outperforms the new PW6B95-D3 and MPW1B95-D3 and is the second most accurate density functional of the study. The best agreement with CCSD(T)/CBS is provided by DSD-B-LYP-D3 double-hybrid functional, although its large-scale applications may be limited by high computational costs. Molecular mechanics does not reproduce the fine energy differences between the RNA backbone substates. We also demonstrate that the differences in the magnitude of the hyperconjugation effect do not correlate with the energy ranking of the backbone conformations. Further, we investigated the 2'-hydroxyl group orientation preferences. For all families, we conducted a QM and MM hydroxyl group rigid scan in gas phase and solvent. We then carried out set of explicit solvent MD simulations of folded RNAs and analyze 2'-hydroxyl group orientations of different backbone families in MD. The solvent energy profiles determined primarily by the sugar pucker match well with the distribution data derived from the simulations. The QM and MM energy profiles predict the same 2'-hydroxyl group orientation preferences. Finally, we demonstrate that the high energy of unfavorable and rarely sampled 2'-hydroxyl group orientations can be attributed to clashes between occupied orbitals.
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Affiliation(s)
- Arnošt Mládek
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic
| | - Pavel Banáš
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Petr Jurečka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Michal Otyepka
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Marie Zgarbová
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacky University , tr. 17. listopadu 12, 771 46, Olomouc, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Královopolská 135, 612 65 Brno, Czech Republic.,CEITEC, Central European Institute of Technology , Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
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4
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Appasamy SD, Ramlan EI, Firdaus-Raih M. Comparative sequence and structure analysis reveals the conservation and diversity of nucleotide positions and their associated tertiary interactions in the riboswitches. PLoS One 2013; 8:e73984. [PMID: 24040136 PMCID: PMC3764141 DOI: 10.1371/journal.pone.0073984] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 07/25/2013] [Indexed: 12/17/2022] Open
Abstract
The tertiary motifs in complex RNA molecules play vital roles to either stabilize the formation of RNA 3D structure or to provide important biological functionality to the molecule. In order to better understand the roles of these tertiary motifs in riboswitches, we examined 11 representative riboswitch PDB structures for potential agreement of both motif occurrences and conservations. A total of 61 unique tertiary interactions were found in the reference structures. In addition to the expected common A-minor motifs and base-triples mainly involved in linking distant regions the riboswitch structures three highly conserved variants of A-minor interactions called G-minors were found in the SAM-I and FMN riboswitches where they appear to be involved in the recognition of the respective ligand’s functional groups. From our structural survey as well as corresponding structure and sequence alignments, the agreement between motif occurrences and conservations are very prominent across the representative riboswitches. Our analysis provide evidence that some of these tertiary interactions are essential components to form the structure where their sequence positions are conserved despite a high degree of diversity in other parts of the respective riboswitches sequences. This is indicative of a vital role for these tertiary interactions in determining the specific biological function of riboswitch.
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Affiliation(s)
- Sri D Appasamy
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM Bangi, Selangor, Malaysia
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5
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Theis C, Höner Zu Siederdissen C, Hofacker IL, Gorodkin J. Automated identification of RNA 3D modules with discriminative power in RNA structural alignments. Nucleic Acids Res 2013; 41:9999-10009. [PMID: 24005040 PMCID: PMC3905863 DOI: 10.1093/nar/gkt795] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Recent progress in predicting RNA structure is moving towards filling the ‘gap’ in 2D RNA structure prediction where, for example, predicted internal loops often form non-canonical base pairs. This is increasingly recognized with the steady increase of known RNA 3D modules. There is a general interest in matching structural modules known from one molecule to other molecules for which the 3D structure is not known yet. We have created a pipeline, metaRNAmodules, which completely automates extracting putative modules from the FR3D database and mapping of such modules to Rfam alignments to obtain comparative evidence. Subsequently, the modules, initially represented by a graph, are turned into models for the RMDetect program, which allows to test their discriminative power using real and randomized Rfam alignments. An initial extraction of 22 495 3D modules in all PDB files results in 977 internal loop and 17 hairpin modules with clear discriminatory power. Many of these modules describe only minor variants of each other. Indeed, mapping of the modules onto Rfam families results in 35 unique locations in 11 different families. The metaRNAmodules pipeline source for the internal loop modules is available at http://rth.dk/resources/mrm.
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Affiliation(s)
- Corinna Theis
- Center for non-coding RNA in Technology and Health, Department of Veterinary Clinical and Animal Science, University of Copenhagen, Grønnegårdsvej 3, DK-1870 Frederiksberg, Denmark, Institute for Theoretical Chemistry, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria and Research Group Bioinformatics and Computational Biology, University of Vienna, Währingerstraße 17, A-1090 Vienna, Austria
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6
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Denning EJ, Priyakumar UD, Nilsson L, MacKerell AD. Impact of 2'-hydroxyl sampling on the conformational properties of RNA: update of the CHARMM all-atom additive force field for RNA. J Comput Chem 2011; 32:1929-43. [PMID: 21469161 PMCID: PMC3082605 DOI: 10.1002/jcc.21777] [Citation(s) in RCA: 288] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 01/24/2011] [Accepted: 01/30/2011] [Indexed: 01/02/2023]
Abstract
Here, we present an update of the CHARMM27 all-atom additive force field for nucleic acids that improves the treatment of RNA molecules. The original CHARMM27 force field parameters exhibit enhanced Watson-Crick base pair opening which is not consistent with experiment, whereas analysis of molecular dynamics (MD) simulations show the 2'-hydroxyl moiety to almost exclusively sample the O3' orientation. Quantum mechanical (QM) studies of RNA related model compounds indicate the energy minimum associated with the O3' orientation to be too favorable, consistent with the MD results. Optimization of the dihedral parameters dictating the energy of the 2'-hydroxyl proton targeting the QM data yielded several parameter sets, which sample both the base and O3' orientations of the 2'-hydroxyl to varying degrees. Selection of the final dihedral parameters was based on reproduction of hydration behavior as related to a survey of crystallographic data and better agreement with experimental NMR J-coupling values. Application of the model, designated CHARMM36, to a collection of canonical and noncanonical RNA molecules reveals overall improved agreement with a range of experimental observables as compared to CHARMM27. The results also indicate the sensitivity of the conformational heterogeneity of RNA to the orientation of the 2'-hydroxyl moiety and support a model whereby the 2'-hydroxyl can enhance the probability of conformational transitions in RNA.
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Affiliation(s)
- Elizabeth J. Denning
- Department of Pharmaceutical Sciences, School of Pharmacy, University
of Maryland, Baltimore, MD 21201
| | - U. Deva Priyakumar
- Department of Pharmaceutical Sciences, School of Pharmacy, University
of Maryland, Baltimore, MD 21201
| | - Lennart Nilsson
- Department of Pharmaceutical Sciences, School of Pharmacy, University
of Maryland, Baltimore, MD 21201
| | - Alexander D. MacKerell
- Department of Pharmaceutical Sciences, School of Pharmacy, University
of Maryland, Baltimore, MD 21201
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7
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Sequence-based identification of 3D structural modules in RNA with RMDetect. Nat Methods 2011; 8:513-21. [PMID: 21552257 DOI: 10.1038/nmeth.1603] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 04/11/2011] [Indexed: 01/24/2023]
Abstract
Structural RNA modules, sets of ordered non-Watson-Crick base pairs embedded between Watson-Crick pairs, have central roles as architectural organizers and sites of ligand binding in RNA molecules, and are recurrently observed in RNA families throughout the phylogeny. Here we describe a computational tool, RNA three-dimensional (3D) modules detection, or RMDetect, for identifying known 3D structural modules in single and multiple RNA sequences in the absence of any other information. Currently, four modules can be searched for: G-bulge loop, kink-turn, C-loop and tandem-GA loop. In control test sequences we found all of the known modules with a false discovery rate of 0.23. Scanning through 1,444 publicly available alignments, we identified 21 yet unreported modules and 141 known modules. RMDetect can be used to refine RNA 2D structure, assemble RNA 3D models, and search and annotate structured RNAs in genomic data.
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Pallan PS, Kreutz C, Bosio S, Micura R, Egli M. Effects of N2,N2-dimethylguanosine on RNA structure and stability: crystal structure of an RNA duplex with tandem m2 2G:A pairs. RNA (NEW YORK, N.Y.) 2008; 14:2125-35. [PMID: 18772248 PMCID: PMC2553729 DOI: 10.1261/rna.1078508] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Methylation of the exocyclic amino group of guanine is a relatively common modification in rRNA and tRNA. Single methylation (N(2)-methylguanosine, m(2)G) is the second most frequently encountered nucleoside analog in Escherichia coli rRNAs. The most prominent case of dual methylation (N(2),N(2)-dimethylguanosine, m(2) (2)G) is found in the majority of eukaryotic tRNAs at base pair m(2) (2)G26:A44. The latter modification eliminates the ability of the N(2) function to donate in hydrogen bonds and alters its pairing behavior, notably vis-à-vis C. Perhaps a less obvious consequence of the N(2),N(2)-dimethyl modification is its role in controlling the pairing modes between G and A. We have determined the crystal structure of a 13-mer RNA duplex with central tandem m(2) (2)G:A pairs. In the structure both pairs adopt an imino-hydrogen bonded, pseudo-Watson-Crick conformation. Thus, the sheared conformation frequently seen in tandem G:A pairs is avoided due to a potential steric clash between an N(2)-methyl group and the major groove edge of A. Additionally, for a series of G:A containing self-complementary RNAs we investigated how methylation affects competitive hairpin versus duplex formation based on UV melting profile analysis.
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Affiliation(s)
- Pradeep S Pallan
- Department of Biochemistry, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232, USA
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9
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Chen G, Kierzek R, Yildirim I, Krugh TR, Turner DH, Kennedy SD. Stacking effects on local structure in RNA: changes in the structure of tandem GA pairs when flanking GC pairs are replaced by isoG-isoC pairs. J Phys Chem B 2007; 111:6718-27. [PMID: 17411085 PMCID: PMC3738747 DOI: 10.1021/jp068732m] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Watson-Crick-like isoG-isoC (iGiC) pair, with the amino and carbonyl groups transposed relative to the Watson-Crick GC pair, provides an expanded alphabet for understanding interactions that shape nucleic acid structure. Here, thermodynamic stabilities of tandem GA pairs flanked by iGiC pairs are reported along with the NMR structures of the RNA self-complementary duplexes (GCiGGAiCGCA)2 and (GGiCGAiGCCA)2. A sheared GA pairing forms in (GCiGGAiCGCA)2, and an imino GA pairing forms in (GGiCGAiGCCA)2. The structures contrast with the formation of tandem imino and sheared GA pairs flanked by GC pairs in the RNA self-complementary duplexes (GCGGACGC)2 and (GGCGAGCC)2, respectively. In both iGiC duplexes, Watson-Crick-like hydrogen bonds are formed between iG and iC, and iGiC substitutions result in less favorable loop stability. The results provide benchmarks for testing computations of molecular interactions that shape RNA three-dimensional structure.
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Affiliation(s)
| | | | | | | | - Douglas H. Turner
- To whom correspondence should be addressed. Phone: (585) 275-3207. Fax: (585) 276-0205.
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Tolbert BS, Kennedy SD, Schroeder SJ, Krugh TR, Turner DH. NMR structures of (rGCUGAGGCU)2 and (rGCGGAUGCU)2: probing the structural features that shape the thermodynamic stability of GA pairs. Biochemistry 2007; 46:1511-22. [PMID: 17279616 PMCID: PMC4032317 DOI: 10.1021/bi061350m] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NMR structures of [see text] and [see text] are reported. The internal loop, [see text], is about 2 kcal/mol more stable than [see text] at 37 degrees C. The duplexes assemble into similar global folds characterized by the formation of tandem sheared GA pairs. The different stabilities of the loops are accompanied by differences in the local structure of the closing GU pairs. In the [see text] internal loop, the GU pairs form canonical wobble configurations with two hydrogen bonds, whereas in [see text], the GU pairs form a single hydrogen bond involving the amino group, GH22, and the carbonyl group, UO4. This pairing is similar to the GU closing pair of the 690 hairpin loop found in E. coli 16S rRNA. The [see text] and [see text] structures reveal how the subtle interplay between stacking and hydrogen bonding determines sequence dependent conformation and thermodynamic stability. Thus, this work provides structural and thermodynamic benchmarks for theoreticians in the ongoing effort to understand the sequence dependence of RNA physicochemical properties.
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Affiliation(s)
- Blanton S. Tolbert
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | - Scott D. Kennedy
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | - Susan J. Schroeder
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019-3051
| | - Thomas R. Krugh
- Department of Chemistry, University of Rochester, Rochester, NY 14627-0216
| | - Douglas H. Turner
- Department of Chemistry, University of Rochester, Rochester, NY 14627-0216
- Center for Pediatric Biomedical Research and Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
- To whom correspondence should be addressed to: , (Phone) 585-275-3207, (Fax) 585-276-0205
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Seio K, Sasami T, Tawarada R, Sekine M. Synthesis of 2'-O-methyl-RNAs incorporating a 3-deazaguanine, and UV melting and computational studies on its hybridization properties. Nucleic Acids Res 2006; 34:4324-34. [PMID: 16936323 PMCID: PMC1636341 DOI: 10.1093/nar/gkl088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
2′-O-Methyl-RNAs incorporating 3-deazaguanine (c3G) were synthesized by use of N,N-diphenylcarbamoyl and N,N-dimethylaminomethylene as its base protecting groups to suppress sheared-type 5′-GA-3′/5′-GA-3′ tandem mismatched base pairing which requires the N3 atom. These modified RNAs hybridized more weakly with the complementary and single mismatch-containing RNAs than the unmodified RNAs. The Tm experiments were performed to clarify the effects of replacement of the fifth G with c3G on stabilization of 2′-O-methyl-(5′-CGGCGAGGAG-3′)/5′-CUCCGAGCCG-3′ and 2′-O-methyl-(5′-CGGGGACGAG-3′)/5′-CUCGGACCCG-3′duplexes, which form sheared-type and face-to-face type 5′-GA-3′/5′-GA-3′ tandem mismatched base pairs, respectively. Consequently, this replacement led to more pronounced destabilization of the former duplex that needs the N3 atom for the sheared-type base pair than the latter that does not need it for the face-to-face type base pair. A similar tendency was observed for 2′-O-methyl-RNA/DNA duplexes. These results suggest that the N3 atom of G plays an important role in stabilization of the canonical G/C base pair as well as the base discrimination and its loss suppressed formation of the undesired sheared-type mismatched base pair. Computational studies based on ab initio calculations suggest that the weaker hydrogen bonding ability and larger dipole moment of c3G can be the origin of the lower Tm.
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Affiliation(s)
- Kohji Seio
- Frontier Collaborative Research Center, Tokyo Institute of Technology4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
- CREST, JST (Japan Science and Technology Agency)4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Takeshi Sasami
- Department of Life Science, Tokyo Institute of Technology4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
- CREST, JST (Japan Science and Technology Agency)4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Ryuya Tawarada
- Department of Life Science, Tokyo Institute of Technology4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
- CREST, JST (Japan Science and Technology Agency)4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
| | - Mitsuo Sekine
- Department of Life Science, Tokyo Institute of Technology4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
- CREST, JST (Japan Science and Technology Agency)4259 Nagatsuta-cho, Midori-ku, Yokohama, Japan
- To whom correspondence should be addressed. Tel: +81 45 924 5706; Fax: +81 45 924 5772;
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12
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Chen G, Kennedy SD, Qiao J, Krugh TR, Turner DH. An alternating sheared AA pair and elements of stability for a single sheared purine-purine pair flanked by sheared GA pairs in RNA. Biochemistry 2006; 45:6889-903. [PMID: 16734425 PMCID: PMC4121271 DOI: 10.1021/bi0524464] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A previous NMR structure of the duplex 5'GGU GGA GGCU/PCCG AAG CCG5' revealed an unusually stable RNA internal loop with three consecutive sheared GA pairs. Here, we report NMR studies of two duplexes, 5'GGU GGA GGCU/PCCA AAG CCG5' (replacing the UG pair with a UA closing pair) and 5'GGU GAA GGCU/PCCG AAG CCG5' (replacing the middle GA pair with an AA pair). An unusually stable loop with three consecutive sheared GA pairs forms in the duplex 5'GGU GGA GGCU/PCCA AAG CCG5'. The structure contrasts with that reported for this loop in the crystal structure of the large ribosomal subunit of Deinococcus radiodurans [Harms, J., Schluenzen, F., Zarivach, R., Bashan, A., Gat, S., Agmon, I., Bartels, H., Franceschi, F., and Yonath, A. (2001) Cell 107, 679-688]. The middle AA pair in the duplex 5'GGU GAA GGCU/PCCG AAG CCG5' rapidly exchanges orientations, resulting in alternative base stacking and pseudosymmetry with exclusively sheared pairs. The U GAA G/G AAG C internal loop is 2.1 kcal/mol less stable than the U GGA G/G AAG C internal loop at 37 degrees C. Structural, energetic, and dynamic consequences upon functional group substitutions within related 3 x 3 and 3 x 6 internal loops are also reported.
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Affiliation(s)
- Gang Chen
- Department of Chemistry, University of Rochester, RC Box 270216, Rochester, NY 14627
| | - Scott D. Kennedy
- Department of Biochemistry and Biophysics, University of Rochester, Rochester, NY 14642
| | - Jing Qiao
- Department of Chemistry, University of Rochester, RC Box 270216, Rochester, NY 14627
| | - Thomas R. Krugh
- Department of Chemistry, University of Rochester, RC Box 270216, Rochester, NY 14627
| | - Douglas H. Turner
- Department of Chemistry, University of Rochester, RC Box 270216, Rochester, NY 14627
- Center for Pediatric Biomedical Research and Department of Pediatrics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642
- To whom correspondence should be addressed. Phone: (585) 275-3207. Fax: (585) 276-0205.
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Jang SB, Hung LW, Jeong MS, Holbrook EL, Chen X, Turner DH, Holbrook SR. The crystal structure at 1.5 angstroms resolution of an RNA octamer duplex containing tandem G.U basepairs. Biophys J 2006; 90:4530-7. [PMID: 16581850 PMCID: PMC1471874 DOI: 10.1529/biophysj.106.081018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The crystal structure of the RNA octamer, 5'-GGCGUGCC-3' has been determined from x-ray diffraction data to 1.5 angstroms resolution. In the crystal, this oligonucleotide forms five self-complementary double-helices in the asymmetric unit. Tandem 5'GU/3'UG basepairs comprise an internal loop in the middle of each duplex. The NMR structure of this octameric RNA sequence is also known, allowing comparison of the variation among the five crystallographic duplexes and the solution structure. The G.U pairs in the five duplexes of the crystal form two direct hydrogen bonds and are stabilized by water molecules that bridge between the base of guanine (N2) and the sugar (O2') of uracil. This contrasts with the NMR structure in which only one direct hydrogen bond is observed for the G.U pairs. The reduced stability of the r(CGUG)2 motif relative to the r(GGUC)2 motif may be explained by the lack of stacking of the uracil bases between the Watson-Crick and G.U pairs as observed in the crystal structure.
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Affiliation(s)
- Se Bok Jang
- Korea Nanobiotechnology Center, Pusan National University, Jangjeon-dong, Keumjeong-gu, Busan, Korea.
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Zhao Q, Nagaswamy U, Lee H, Xia Y, Huang HC, Gao X, Fox GE. NMR structure and Mg2+ binding of an RNA segment that underlies the L7/L12 stalk in the E.coli 50S ribosomal subunit. Nucleic Acids Res 2005; 33:3145-53. [PMID: 15939932 PMCID: PMC1143578 DOI: 10.1093/nar/gki621] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Helix 42 of Domain II of Escherichia coli 23S ribosomal RNA underlies the L7/L12 stalk in the ribosome and may be significant in positioning this feature relative to the rest of the 50S ribosomal subunit. Unlike the Haloarcula marismortui and Deinococcus radiodurans examples, the lower portion of helix 42 in E.coli contains two consecutive G*A oppositions with both adenines on the same side of the stem. Herein, the structure of an analog of positions 1037-1043 and 1112-1118 in the helix 42 region is reported. NMR spectra and structure calculations support a cis Watson-Crick/Watson-Crick (cis W.C.) G*A conformation for the tandem (G*A)2 in the analog and a minimally perturbed helical duplex stem. Mg2+ titration studies imply that the cis W.C. geometry of the tandem (G*A)2 probably allows O6 of G20 and N1 of A4 to coordinate with a Mg2+ ion as indicated by the largest chemical shift changes associated with the imino group of G20 and the H8 of G20 and A4. A cross-strand bridging Mg2+ coordination has also been found in a different sequence context in the crystal structure of H.marismortui 23S rRNA, and therefore it may be a rare but general motif in Mg2+ coordination.
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Affiliation(s)
- Qin Zhao
- Department of Biology and Biochemistry, University of HoustonHouston, TX 77204-5001, USA
| | - Uma Nagaswamy
- Department of Biology and Biochemistry, University of HoustonHouston, TX 77204-5001, USA
| | - Hunjoong Lee
- Department of Chemistry, University of HoustonHouston, TX 77204-5001, USA
| | - Youlin Xia
- Department of Chemistry, University of HoustonHouston, TX 77204-5001, USA
| | - Hung-Chung Huang
- Department of Biology and Biochemistry, University of HoustonHouston, TX 77204-5001, USA
| | - Xiaolian Gao
- Department of Biology and Biochemistry, University of HoustonHouston, TX 77204-5001, USA
- Department of Chemistry, University of HoustonHouston, TX 77204-5001, USA
| | - George E. Fox
- Department of Biology and Biochemistry, University of HoustonHouston, TX 77204-5001, USA
- To whom correspondence should be addressed. Tel: +1 713 743 8363; Fax: +1 713 743 8351;
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