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Vögele J, Duchardt-Ferner E, Bains JK, Knezic B, Wacker A, Sich C, Weigand J, Šponer J, Schwalbe H, Krepl M, Wöhnert J. Structure of an internal loop motif with three consecutive U•U mismatches from stem-loop 1 in the 3'-UTR of the SARS-CoV-2 genomic RNA. Nucleic Acids Res 2024; 52:6687-6706. [PMID: 38783391 PMCID: PMC11194097 DOI: 10.1093/nar/gkae349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 03/27/2024] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
The single-stranded RNA genome of SARS-CoV-2 is highly structured. Numerous helical stem-loop structures interrupted by mismatch motifs are present in the functionally important 5'- and 3'-UTRs. These mismatches modulate local helical geometries and feature unusual arrays of hydrogen bonding donor and acceptor groups. However, their conformational and dynamical properties cannot be directly inferred from chemical probing and are difficult to predict theoretically. A mismatch motif (SL1-motif) consisting of three consecutive U•U base pairs is located in stem-loop 1 of the 3'-UTR. We combined NMR-spectroscopy and MD-simulations to investigate its structure and dynamics. All three U•U base pairs feature two direct hydrogen bonds and are as stable as Watson-Crick A:U base pairs. Plasmodium falciparum 25S rRNA contains a triple U•U mismatch motif (Pf-motif) differing from SL1-motif only with respect to the orientation of the two closing base pairs. Interestingly, while the geometry of the outer two U•U mismatches was identical in both motifs the preferred orientation of the central U•U mismatch was different. MD simulations and potassium ion titrations revealed that the potassium ion-binding mode to the major groove is connected to the different preferred geometries of the central base pair in the two motifs.
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Affiliation(s)
- Jennifer Vögele
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Elke Duchardt-Ferner
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Jasleen Kaur Bains
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Institute of Organic Chemistry and Chemical Biology, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Bozana Knezic
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Institute of Organic Chemistry and Chemical Biology, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Anna Wacker
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Institute of Organic Chemistry and Chemical Biology, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Christian Sich
- Volkswagen AG, Brieffach 1617/0, 38436 Wolfsburg, Germany
| | - Julia E Weigand
- Institute of Pharmaceutical Chemistry, University of Marburg, Marbacher Weg 6, 35037 Marburg, Germany
| | - Jiří Šponer
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 00 Brno, Czech Republic
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Institute of Organic Chemistry and Chemical Biology, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany
| | - Miroslav Krepl
- Institute of Biophysics of the Czech Academy of Sciences, Kralovopolska 135, 612 00 Brno, Czech Republic
| | - Jens Wöhnert
- Institute of Molecular Biosciences, Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
- Center for Biomolecular Magnetic Resonance (BMRZ), Goethe-University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt, Germany
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Błaszczyk L, Ryczek M, Das B, Mateja-Pluta M, Bejger M, Śliwiak J, Nakatani K, Kiliszek A. Antisense RNA C9orf72 hexanucleotide repeat associated with amyotrophic lateral sclerosis and frontotemporal dementia forms a triplex-like structure and binds small synthetic ligand. Nucleic Acids Res 2024; 52:6707-6717. [PMID: 38738637 PMCID: PMC11194091 DOI: 10.1093/nar/gkae376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 04/05/2024] [Accepted: 04/26/2024] [Indexed: 05/14/2024] Open
Abstract
The abnormal expansion of GGGGCC/GGCCCC hexanucleotide repeats (HR) in C9orf72 is associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Structural polymorphisms of HR result in the multifactorial pathomechanism of ALS/FTD. Consequently, many ongoing studies are focused at developing therapies targeting pathogenic HR RNA. One of them involves small molecules blocking sequestration of important proteins, preventing formation of toxic nuclear foci. However, rational design of potential therapeutics is hindered by limited number of structural studies of RNA-ligand complexes. We determined the crystal structure of antisense HR RNA in complex with ANP77 ligand (1.1 Å resolution) and in the free form (0.92 and 1.5 Å resolution). HR RNA folds into a triplex structure composed of four RNA chains. ANP77 interacted with two neighboring single-stranded cytosines to form pseudo-canonical base pairs by adopting sandwich-like conformation and adjusting the position of its naphthyridine units to the helical twist of the RNA. In the unliganded structure, the cytosines formed a peculiar triplex i-motif, assembled by trans C•C+ pair and a third cytosine located at the Hoogsteen edge of the C•C+ pair. These results extend our knowledge of the structural polymorphisms of HR and can be used for rational design of small molecules targeting disease-related RNAs.
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Affiliation(s)
- Leszek Błaszczyk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poland
| | - Marcin Ryczek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poland
| | - Bimolendu Das
- Department of Regulatory Bioorganic Chemistry, SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan
| | - Martyna Mateja-Pluta
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poland
| | - Magdalena Bejger
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poland
| | - Joanna Śliwiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poland
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan
| | - Agnieszka Kiliszek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704, Poland
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3
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Kiliszek A, Pluta M, Bejger M, Rypniewski W. Structure and thermodynamics of a UGG motif interacting with Ba2+ and other metal ions: accommodating changes in the RNA structure and the presence of a G(syn)-G(syn) pair. RNA (NEW YORK, N.Y.) 2022; 29:rna.079414.122. [PMID: 36319090 PMCID: PMC9808570 DOI: 10.1261/rna.079414.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
The self-complementary triplet 5'UGG3'/5'UGG3' is a particular structural motif containing noncanonical G-G pair and two U·G wobble pairs. It constitutes a specific structural and electrostatic environment attracting metal ions, particularly Ba2+ ions. Crystallographic research has shown that two Ba2+ cations are located in the major groove of the helix and interact directly with the UGG triplet. A comparison with the unliganded structure has revealed global changes in the RNA structure in the presence of metal ions, whereas thermodynamic measurements have shown increased stability. Moreover, in the structure with Ba2+, an unusual noncanonical G(syn)-G(syn) pair is observed instead of the common G(anti)-G(syn). We further elucidate the metal binding properties of the UGG/UGG triplet by performing crystallographic and thermodynamic studies using DSC and UV melting with other metal ions. The results explain the preferences of the UGG sequence for Ba2+ cations and point to possible applications of this metal-binding propensity.
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Artemyeva-Isman OV, Porter ACG. U5 snRNA Interactions With Exons Ensure Splicing Precision. Front Genet 2021; 12:676971. [PMID: 34276781 PMCID: PMC8283771 DOI: 10.3389/fgene.2021.676971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/12/2021] [Indexed: 11/13/2022] Open
Abstract
Imperfect conservation of human pre-mRNA splice sites is necessary to produce alternative isoforms. This flexibility is combined with the precision of the message reading frame. Apart from intron-termini GU_AG and the branchpoint A, the most conserved are the exon-end guanine and +5G of the intron start. Association between these guanines cannot be explained solely by base-pairing with U1 snRNA in the early spliceosome complex. U6 succeeds U1 and pairs +5G in the pre-catalytic spliceosome, while U5 binds the exon end. Current U5 snRNA reconstructions by CryoEM cannot explain the conservation of the exon-end G. Conversely, human mutation analyses show that guanines of both exon termini can suppress splicing mutations. Our U5 hypothesis explains the mechanism of splicing precision and the role of these conserved guanines in the pre-catalytic spliceosome. We propose: (1) optimal binding register for human exons and U5-the exon junction positioned at U5Loop1 C39|C38; (2) common mechanism for base-pairing of human U5 snRNA with diverse exons and bacterial Ll.LtrB intron with new loci in retrotransposition-guided by base pair geometry; and (3) U5 plays a significant role in specific exon recognition in the pre-catalytic spliceosome. Statistical analyses showed increased U5 Watson-Crick pairs with the 5'exon in the absence of +5G at the intron start. In 5'exon positions -3 and -5, this effect is specific to U5 snRNA rather than U1 snRNA of the early spliceosome. Increased U5 Watson-Crick pairs with 3'exon position +1 coincide with substitutions of the conserved -3C at the intron 3'end. Based on mutation and X-ray evidence, we propose that -3C pairs with U2 G31 juxtaposing the branchpoint and the 3'intron end. The intron-termini pair, formed in the pre-catalytic spliceosome to be ready for transition after branching, and the early involvement of the 3'intron end ensure that the 3'exon contacts U5 in the pre-catalytic complex. We suggest that splicing precision is safeguarded cooperatively by U5, U6, and U2 snRNAs that stabilize the pre-catalytic complex by Watson-Crick base pairing. In addition, our new U5 model explains the splicing effect of exon-start +1G mutations: U5 Watson-Crick pairs with exon +2C/+3G strongly promote exon inclusion. We discuss potential applications for snRNA therapeutics and gene repair by reverse splicing.
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Affiliation(s)
- Olga V Artemyeva-Isman
- Gene Targeting Group, Centre for Haematology, Department of Immunology and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Andrew C G Porter
- Gene Targeting Group, Centre for Haematology, Department of Immunology and Inflammation, Faculty of Medicine, Imperial College London, London, United Kingdom
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Gumna J, Purzycka KJ, Ahn HW, Garfinkel DJ, Pachulska-Wieczorek K. Retroviral-like determinants and functions required for dimerization of Ty1 retrotransposon RNA. RNA Biol 2019; 16:1749-1763. [PMID: 31469343 PMCID: PMC6844567 DOI: 10.1080/15476286.2019.1657370] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
During replication of long terminal repeat (LTR)-retrotransposons, their proteins and genome (g) RNA assemble into virus-like particles (VLPs) that are not infectious but functionally related to retroviral virions. Both virions and VLPs contain gRNA in a dimeric form, but contrary to retroviruses, little is known about how gRNA dimerization and packaging occurs in LTR-retrotransposons. The LTR-retrotransposon Ty1 from Saccharomyces cerevisiae is an informative model for studying LTR-retrotransposon and retrovirus replication. Using structural, mutational and functional analyses, we explored dimerization of Ty1 genomic RNA. We provide direct evidence that interactions of self-complementary PAL1 and PAL2 palindromic sequences localized within the 5′UTR are essential for Ty1 gRNA dimer formation. Mutations disrupting PAL1-PAL2 complementarity restricted RNA dimerization in vitro and Ty1 mobility in vivo. Although dimer formation and mobility of these mutants was inhibited, our work suggests that Ty1 RNA can dimerize via alternative contact points. In contrast to previous studies, we cannot confirm a role for PAL3, tRNAiMet as well as recently proposed initial kissing-loop interactions in dimer formation. Our data also supports the critical role of Ty1 Gag in RNA dimerization. Mature Ty1 Gag binds in the proximity of sequences involved in RNA dimerization and tRNAiMet annealing, but the 5′ pseudoknot in Ty1 RNA may constitute a preferred Gag-binding site. Taken together, these results expand our understanding of genome dimerization and packaging strategies utilized by LTR-retroelements.
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Affiliation(s)
- Julita Gumna
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Katarzyna J Purzycka
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Hyo Won Ahn
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - David J Garfinkel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Katarzyna Pachulska-Wieczorek
- Department of Structure and Function of Retrotransposons, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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Hale MA, Johnson NE, Berglund JA. Repeat-associated RNA structure and aberrant splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194405. [PMID: 31323433 DOI: 10.1016/j.bbagrm.2019.07.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Over 30 hereditary disorders attributed to the expansion of microsatellite repeats have been identified. Despite variant nucleotide content, number of consecutive repeats, and different locations in the genome, many of these diseases have pathogenic RNA gain-of-function mechanisms. The repeat-containing RNAs can form structures in vitro predicted to contribute to the disease through assembly of intracellular RNA aggregates termed foci. The expanded repeat RNAs within these foci sequester RNA binding proteins (RBPs) with important roles in the regulation of RNA metabolism, most notably alternative splicing (AS). These deleterious interactions lead to downstream alterations in transcriptome-wide AS directly linked with disease symptoms. This review summarizes existing knowledge about the association between the repeat RNA structures and RBPs as well as the resulting aberrant AS patterns, specifically in the context of myotonic dystrophy. The connection between toxic, structured RNAs and dysregulation of AS in other repeat expansion diseases is also discussed. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Melissa A Hale
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Nicholas E Johnson
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - J Andrew Berglund
- The RNA Institute, Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
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7
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Dans PD, Gallego D, Balaceanu A, Darré L, Gómez H, Orozco M. Modeling, Simulations, and Bioinformatics at the Service of RNA Structure. Chem 2019. [DOI: 10.1016/j.chempr.2018.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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8
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Keller H, Weickhmann AK, Bock T, Wöhnert J. Adenine protonation enables cyclic-di-GMP binding to cyclic-GAMP sensing riboswitches. RNA (NEW YORK, N.Y.) 2018; 24:1390-1402. [PMID: 30006500 PMCID: PMC6140456 DOI: 10.1261/rna.067470.118] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Accepted: 07/09/2018] [Indexed: 05/22/2023]
Abstract
In certain structural or functional contexts, RNA structures can contain protonated nucleotides. However, a direct role for stably protonated nucleotides in ligand binding and ligand recognition has not yet been demonstrated unambiguously. Previous X-ray structures of c-GAMP binding riboswitch aptamer domains in complex with their near-cognate ligand c-di-GMP suggest that an adenine of the riboswitch either forms two hydrogen bonds to a G nucleotide of the ligand in the unusual enol tautomeric form or that the adenine in its N1 protonated form binds the G nucleotide of the ligand in its canonical keto tautomeric state. By using NMR spectroscopy we demonstrate that the c-GAMP riboswitches bind c-di-GMP using a stably protonated adenine in the ligand binding pocket. Thereby, we provide novel insights into the putative biological functions of protonated nucleotides in RNA, which in this case influence the ligand selectivity in a riboswitch.
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Affiliation(s)
- Heiko Keller
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - A Katharina Weickhmann
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Thomas Bock
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jens Wöhnert
- Institute for Molecular Biosciences and Center of Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
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9
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Ishida R, Iwahashi H. Detection of protonated non-Watson-Crick base pairs using electrospray ionization mass spectrometry. J Biochem 2018; 163:215-222. [PMID: 29087477 DOI: 10.1093/jb/mvx073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/11/2017] [Indexed: 11/13/2022] Open
Abstract
Many studies have shown that protonated nucleic acid base pairs are involved in a wide variety of nucleic acid structures. However, little information is available on relative stability of hemiprotonated self- and non-self-dimers at monomer level. We used electrospray ionization mass spectrometry (ESI-MS) to evaluate the relative stability under various concentrations of hydrogen ion. These enable conjecture of the formation of protonated non-Watson-Crick base pairs based on DNA and RNA base sequence. In the present study, we observed that ESI-MS peaks corresponded to respective self-dimers for all examined nucleosides except for adenosine. Peak heights depended on the concentration of hydrogen ion. The ESI-MS peak heights of the hemiprotonated cytidine dimers and the hemiprotonated thymidine dimer sharply increased with increased concentration of hydrogen ion, suggesting direct participation of hydrogen ion in dimer formations. In ESI-MS measurements of the solutions containing adenosine, cytidine, thymidine and guanosine, we observed protonated cytidine-guanosine dimer (CH+-G) and protonated cytidine-thymidine dimer (CH+-T) in addition to hemiprotonated cytidine-cytidine dimer (CH+-C) with following relative peak height, (CH+-C) > (CH+-G) ≈ (CH+-T) > (CH+-A). Additionally, in the ESI-MS measurements of solutions containing adenosine, thymidine and guanosine, we observed a considerable amount of protonated adenosine-guanosine (AH+-G) and protonated adenosine-thymidine (AH+-T).
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Affiliation(s)
- Riyoko Ishida
- Analytical Biochemistry, Wakayama Medical University, 580 Mikazura, Wakayama, Wakayama 641-0011, Japan
| | - Hideo Iwahashi
- Analytical Biochemistry, Wakayama Medical University, 580 Mikazura, Wakayama, Wakayama 641-0011, Japan
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Hartono YD, Ito M, Villa A, Nilsson L. Computational Study of Uracil Tautomeric Forms in the Ribosome: The Case of Uracil and 5-Oxyacetic Acid Uracil in the First Anticodon Position of tRNA. J Phys Chem B 2018; 122:1152-1160. [PMID: 29260566 DOI: 10.1021/acs.jpcb.7b10878] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Tautomerism is important in many biomolecular interactions, not least in RNA biology. Crystallographic studies show the possible presence of minor tautomer forms of transfer-RNA (tRNA) anticodon bases in the ribosome. The hydrogen positions are not resolved in the X-ray studies, and we have used ab initio calculations and molecular dynamics simulations to understand if and how the minor enol form of uracil (U), or the modified uracil 5-oxyacetic acid (cmo5U), can be accommodated in the tRNA-messenger-RNA interactions in the ribosome decoding center. Ab initio calculations on isolated bases show that the modification affects the keto-enol equilibrium of the uracil base only slightly; the keto form is dominant (>99.99%) in both U and cmo5U. Other factors such as interactions with the surrounding nucleotides or ions would be required to shift the equilibrium toward the enol tautomer. Classical molecular simulations show a better agreement with the X-ray structures for the enol form, but free energy calculations indicate that the most stable form is the keto. In the ribosome, the enol tautomers of U and cmo5U pair with a guanine forming two hydrogen bonds, which do not involve the enol group. The oxyacetic acid modification has a minor effect on the keto-enol equilibrium.
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Affiliation(s)
- Yossa Dwi Hartono
- Department of Biosciences and Nutrition, Karolinska Institutet , SE-141 83 Huddinge, Sweden.,Division of Structural Biology and Biochemistry, School of Biological Sciences, Nanyang Technological University , 60 Nanyang Drive, 637551 Singapore
| | - Mika Ito
- Department of Biosciences and Nutrition, Karolinska Institutet , SE-141 83 Huddinge, Sweden
| | - Alessandra Villa
- Department of Biosciences and Nutrition, Karolinska Institutet , SE-141 83 Huddinge, Sweden
| | - Lennart Nilsson
- Department of Biosciences and Nutrition, Karolinska Institutet , SE-141 83 Huddinge, Sweden
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Phan A, Mailey K, Saeki J, Gu X, Schroeder SJ. Advancing viral RNA structure prediction: measuring the thermodynamics of pyrimidine-rich internal loops. RNA (NEW YORK, N.Y.) 2017; 23:770-781. [PMID: 28213527 PMCID: PMC5393185 DOI: 10.1261/rna.059865.116] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/13/2017] [Indexed: 05/24/2023]
Abstract
Accurate thermodynamic parameters improve RNA structure predictions and thus accelerate understanding of RNA function and the identification of RNA drug binding sites. Many viral RNA structures, such as internal ribosome entry sites, have internal loops and bulges that are potential drug target sites. Current models used to predict internal loops are biased toward small, symmetric purine loops, and thus poorly predict asymmetric, pyrimidine-rich loops with >6 nucleotides (nt) that occur frequently in viral RNA. This article presents new thermodynamic data for 40 pyrimidine loops, many of which can form UU or protonated CC base pairs. Uracil and protonated cytosine base pairs stabilize asymmetric internal loops. Accurate prediction rules are presented that account for all thermodynamic measurements of RNA asymmetric internal loops. New loop initiation terms for loops with >6 nt are presented that do not follow previous assumptions that increasing asymmetry destabilizes loops. Since the last 2004 update, 126 new loops with asymmetry or sizes greater than 2 × 2 have been measured. These new measurements significantly deepen and diversify the thermodynamic database for RNA. These results will help better predict internal loops that are larger, pyrimidine-rich, and occur within viral structures such as internal ribosome entry sites.
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Affiliation(s)
- Andy Phan
- Department of Chemistry and Biochemistry
| | | | | | - Xiaobo Gu
- Department of Chemistry and Biochemistry
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Susan J Schroeder
- Department of Chemistry and Biochemistry
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
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12
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Błaszczyk L, Rypniewski W, Kiliszek A. Structures of RNA repeats associated with neurological diseases. WILEY INTERDISCIPLINARY REVIEWS-RNA 2017; 8. [PMID: 28130835 DOI: 10.1002/wrna.1412] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 10/25/2016] [Accepted: 11/12/2016] [Indexed: 01/04/2023]
Abstract
All RNA molecules possess a 'propensity' to fold into complex secondary and tertiary structures. Although they are composed of only four types of nucleotides, they show an enormous structural richness which reflects their diverse functions in the cell. However, in some cases the folding of RNA can have deleterious consequences. Aberrantly expanded, repeated RNA sequences can exhibit gain-of-function abnormalities and become pathogenic, giving rise to many incurable neurological diseases. Most RNA repeats form long hairpin structures whose stem consists of noncanonical base pairs interspersed among Watson-Crick pairs. The expanded hairpins have an ability to sequester important proteins and form insoluble nuclear foci. The RNA pathology, common to many repeat disorders, has drawn attention to the structures of the RNA repeats. In this review, we summarize secondary structure probing and crystallographic studies of disease-related RNA repeat sequences. We discuss the unique structural features which can contribute to the pathogenic properties of the repeated runs. In addition, we present the newest reports concerning structural data linked to therapeutic approaches. WIREs RNA 2017, 8:e1412. doi: 10.1002/wrna.1412 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Leszek Błaszczyk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Wojciech Rypniewski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Agnieszka Kiliszek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
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13
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Dodd DW, Tomchick DR, Corey DR, Gagnon KT. Pathogenic C9ORF72 Antisense Repeat RNA Forms a Double Helix with Tandem C:C Mismatches. Biochemistry 2016; 55:1283-6. [PMID: 26878348 DOI: 10.1021/acs.biochem.6b00136] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Expansion of a GGGGCC/CCCCGG repeat sequence in the first intron of the C9ORF72 gene is a leading cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). In this combined disorder, called c9FTD/ALS, the expansion is bidirectionally transcribed into sense and antisense repeat RNA associated with disease. To better understand the role of C9ORF72 repeat RNA in molecular disease pathology, we determined crystal structures of a [(CCCCGG)3(CCCC)] model antisense repeat RNA to 1.47 Å resolution. The RNA structure was an A-form-like double helix composed of repeating and regularly spaced tandem C:C mismatch pairs that perturbed helical geometry and surface charge. Solution studies revealed a preference for A-form-like helical conformations as the repeat number increased. Results provide a structural starting point for rationalizing the contribution of repeat RNA to c9FTD/ALS molecular disease mechanisms and for developing molecules to target C9ORF72 repeat RNA as potential therapeutics.
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Affiliation(s)
- David W Dodd
- Department of Pharmacology, ‡Department of Biophysics, and §Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.,Department of Biochemistry and Molecular Biology, School of Medicine, and ⊥Department of Chemistry and Biochemistry, Southern Illinois University , Carbondale, Illinois 62901, United States
| | - Diana R Tomchick
- Department of Pharmacology, ‡Department of Biophysics, and §Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.,Department of Biochemistry and Molecular Biology, School of Medicine, and ⊥Department of Chemistry and Biochemistry, Southern Illinois University , Carbondale, Illinois 62901, United States
| | - David R Corey
- Department of Pharmacology, ‡Department of Biophysics, and §Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.,Department of Biochemistry and Molecular Biology, School of Medicine, and ⊥Department of Chemistry and Biochemistry, Southern Illinois University , Carbondale, Illinois 62901, United States
| | - Keith T Gagnon
- Department of Pharmacology, ‡Department of Biophysics, and §Department of Biochemistry, University of Texas Southwestern Medical Center , Dallas, Texas 75390, United States.,Department of Biochemistry and Molecular Biology, School of Medicine, and ⊥Department of Chemistry and Biochemistry, Southern Illinois University , Carbondale, Illinois 62901, United States
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