1
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Qian C, Wang L. Unraveling the Structure-Spectrum Relationship of Yeast Phenylalanine Transfer RNA: Insights from Theoretical Modeling of Infrared Spectroscopy. Biochemistry 2024; 63:2075-2088. [PMID: 39099399 DOI: 10.1021/acs.biochem.4c00236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Yeast phenylalanine tRNA (tRNAphe) is a paradigmatic model in structural biology. In this work, we combine molecular dynamics simulations and spectroscopy modeling to establish a direct link between its structure, conformational dynamics, and infrared (IR) spectra. Employing recently developed vibrational frequency maps and coupling models, we apply a mixed quantum/classical treatment of the line shape theory to simulate the IR spectra of tRNAphe in the 1600-1800 cm-1 region across its folded and unfolded conformations and under varying concentrations of Mg2+ ions. The predicted IR spectra of folded and unfolded tRNAphe are in good agreement with experimental measurements, validating our theoretical framework. We then elucidate how the characteristic L-shaped tertiary structure of the tRNA and its modulation in response to diverse chemical environments give rise to distinct IR absorption peaks and line shapes. These calculations effectively bridge IR spectroscopy experiments and atomistic molecular simulations, unraveling the molecular origins of the observed IR spectra of tRNAphe. This work presents a robust theoretical protocol for modeling the IR spectroscopy of nucleic acids, which will facilitate its application as a sensitive probe for detecting the fluctuating secondary and tertiary structures of these essential biological macromolecules.
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Affiliation(s)
- Cheng Qian
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Lu Wang
- Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States
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2
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Nowzari ZR, D'Esposito RJ, Vangaveti S, Chen AA. Elucidating the influence of RNA modifications and Magnesium ions on tRNA Phe conformational dynamics in S. cerevisiae : Insights from Replica Exchange Molecular Dynamics simulations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584441. [PMID: 38559076 PMCID: PMC10979867 DOI: 10.1101/2024.03.11.584441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Post-transcriptional modifications in RNA can significantly impact their structure and function. In particular, transfer RNAs (tRNAs) are heavily modified, with around 100 different naturally occurring nucleotide modifications contributing to codon bias and decoding efficiency. Here, we describe our efforts to investigate the impact of RNA modifications on the structure and stability of tRNA Phenylalanine (tRNA Phe ) from S. cerevisiae using molecular dynamics (MD) simulations. Through temperature replica exchange MD (T-REMD) studies, we explored the unfolding pathway to understand how RNA modifications influence the conformational dynamics of tRNA Phe , both in the presence and absence of magnesium ions (Mg 2+ ). We observe that modified nucleotides in key regions of the tRNA establish a complex network of hydrogen bonds and stacking interactions which is essential for tertiary structure stability of the tRNA. Furthermore, our simulations show that modifications facilitate the formation of ion binding sites on the tRNA. However, high concentrations of Mg 2+ ions can stabilize the tRNA tertiary structure in the absence of modifications. Our findings illuminate the intricate interactions between modifications, magnesium ions, and RNA structural stability.
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3
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Brooks WH. Polyamine Dysregulation and Nucleolar Disruption in Alzheimer's Disease. J Alzheimers Dis 2024; 98:837-857. [PMID: 38489184 DOI: 10.3233/jad-231184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
A hypothesis of Alzheimer's disease etiology is proposed describing how cellular stress induces excessive polyamine synthesis and recycling which can disrupt nucleoli. Polyamines are essential in nucleolar functions, such as RNA folding and ribonucleoprotein assembly. Changes in the nucleolar pool of anionic RNA and cationic polyamines acting as counterions can cause significant nucleolar dynamics. Polyamine synthesis reduces S-adenosylmethionine which, at low levels, triggers tau phosphorylation. Also, polyamine recycling reduces acetyl-CoA needed for acetylcholine, which is low in Alzheimer's disease. Extraordinary nucleolar expansion and/or contraction can disrupt epigenetic control in peri-nucleolar chromatin, such as chromosome 14 with the presenilin-1 gene; chromosome 21 with the amyloid precursor protein gene; chromosome 17 with the tau gene; chromosome 19 with the APOE4 gene; and the inactive X chromosome (Xi; aka "nucleolar satellite") with normally silent spermine synthase (polyamine synthesis) and spermidine/spermine-N1-acetyltransferase (polyamine recycling) alleles. Chromosomes 17, 19 and the Xi have high concentrations of Alu elements which can be transcribed by RNA polymerase III if positioned nucleosomes are displaced from the Alu elements. A sudden flood of Alu RNA transcripts can competitively bind nucleolin which is usually bound to Alu sequences in structural RNAs that stabilize the nucleolar heterochromatic shell. This Alu competition leads to loss of nucleolar integrity with leaking of nucleolar polyamines that cause aggregation of phosphorylated tau. The hypothesis was developed with key word searches (e.g., PubMed) using relevant terms (e.g., Alzheimer's, lupus, nucleolin) based on a systems biology approach and exploring autoimmune disease tautology, gaining synergistic insights from other diseases.
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4
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Mao G, Srivastava AS, Wu S, Kosek D, Kirsebom LA. Importance of residue 248 in Escherichia coli RNase P RNA mediated cleavage. Sci Rep 2023; 13:14140. [PMID: 37644068 PMCID: PMC10465520 DOI: 10.1038/s41598-023-41203-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 08/23/2023] [Indexed: 08/31/2023] Open
Abstract
tRNA genes are transcribed as precursors and RNase P generates the matured 5' end of tRNAs. It has been suggested that residue - 1 (the residue immediately 5' of the scissile bond) in the pre-tRNA interacts with the well-conserved bacterial RNase P RNA (RPR) residue A248 (Escherichia coli numbering). The way A248 interacts with residue - 1 is not clear. To gain insight into the role of A248, we analyzed cleavage as a function of A248 substitutions and N-1 nucleobase identity by using pre-tRNA and three model substrates. Our findings are consistent with a model where the structural topology of the active site varies and depends on the identity of the nucleobases at, and in proximity to, the cleavage site and their potential to interact. This leads to positioning of Mg2+ that activates the water that acts as the nucleophile resulting in efficient and correct cleavage. We propose that in addition to be involved in anchoring the substrate the role of A248 is to exclude bulk water from access to the amino acid acceptor stem, thereby preventing non-specific hydrolysis of the pre-tRNA. Finally, base stacking is discussed as a way to protect functionally important base-pairing interactions from non-specific hydrolysis, thereby ensuring high fidelity during RNA processing and the decoding of mRNA.
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Affiliation(s)
- Guanzhong Mao
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - Abhishek S Srivastava
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - Shiying Wu
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - David Kosek
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden
| | - Leif A Kirsebom
- Department of Cell and Molecular Biology, Biomedical Centre, Box 596, 751 24, Uppsala, Sweden.
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5
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Biela A, Hammermeister A, Kaczmarczyk I, Walczak M, Koziej L, Lin TY, Glatt S. The diverse structural modes of tRNA binding and recognition. J Biol Chem 2023; 299:104966. [PMID: 37380076 PMCID: PMC10424219 DOI: 10.1016/j.jbc.2023.104966] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/20/2023] [Accepted: 06/22/2023] [Indexed: 06/30/2023] Open
Abstract
tRNAs are short noncoding RNAs responsible for decoding mRNA codon triplets, delivering correct amino acids to the ribosome, and mediating polypeptide chain formation. Due to their key roles during translation, tRNAs have a highly conserved shape and large sets of tRNAs are present in all living organisms. Regardless of sequence variability, all tRNAs fold into a relatively rigid three-dimensional L-shaped structure. The conserved tertiary organization of canonical tRNA arises through the formation of two orthogonal helices, consisting of the acceptor and anticodon domains. Both elements fold independently to stabilize the overall structure of tRNAs through intramolecular interactions between the D- and T-arm. During tRNA maturation, different modifying enzymes posttranscriptionally attach chemical groups to specific nucleotides, which not only affect translation elongation rates but also restrict local folding processes and confer local flexibility when required. The characteristic structural features of tRNAs are also employed by various maturation factors and modification enzymes to assure the selection, recognition, and positioning of specific sites within the substrate tRNAs. The cellular functional repertoire of tRNAs continues to extend well beyond their role in translation, partly, due to the expanding pool of tRNA-derived fragments. Here, we aim to summarize the most recent developments in the field to understand how three-dimensional structure affects the canonical and noncanonical functions of tRNA.
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Affiliation(s)
- Anna Biela
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | | | - Igor Kaczmarczyk
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland; Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Marta Walczak
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland; Doctoral School of Exact and Natural Sciences, Jagiellonian University, Krakow, Poland
| | - Lukasz Koziej
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland
| | - Ting-Yu Lin
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland.
| | - Sebastian Glatt
- Malopolska Centre of Biotechnology, Jagiellonian University, Krakow, Poland.
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6
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Guo X, Su M. The Origin of Translation: Bridging the Nucleotides and Peptides. Int J Mol Sci 2022; 24:ijms24010197. [PMID: 36613641 PMCID: PMC9820756 DOI: 10.3390/ijms24010197] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/09/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
Extant biology uses RNA to record genetic information and proteins to execute biochemical functions. Nucleotides are translated into amino acids via transfer RNA in the central dogma. tRNA is essential in translation as it connects the codon and the cognate amino acid. To reveal how the translation emerged in the prebiotic context, we start with the structure and dissection of tRNA, followed by the theory and hypothesis of tRNA and amino acid recognition. Last, we review how amino acids assemble on the tRNA and further form peptides. Understanding the origin of life will also promote our knowledge of artificial living systems.
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Affiliation(s)
- Xuyuan Guo
- School of Genetics and Microbiology, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, D02 PN40 Dublin, Ireland
| | - Meng Su
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK
- Correspondence:
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7
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Abstract
tRNAs are key adaptor molecules that decipher the genetic code during translation of mRNAs in protein synthesis. In contrast to the traditional view of tRNAs as ubiquitously expressed housekeeping molecules, awareness is now growing that tRNA-encoding genes display tissue-specific and cell type-specific patterns of expression, and that tRNA gene expression and function are both dynamically regulated by post-transcriptional RNA modifications. Moreover, dysregulation of tRNAs, mediated by alterations in either their abundance or function, can have deleterious consequences that contribute to several distinct human diseases, including neurological disorders and cancer. Accumulating evidence shows that reprogramming of mRNA translation through altered tRNA activity can drive pathological processes in a codon-dependent manner. This Review considers the emerging evidence in support of the precise control of functional tRNA levels as an important regulatory mechanism that coordinates mRNA translation and protein expression in physiological cell homeostasis, and highlights key examples of human diseases that are linked directly to tRNA dysregulation.
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Affiliation(s)
- Esteban A Orellana
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Elisabeth Siegal
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA.
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.
- Harvard Initiative for RNA Medicine, Harvard University, Boston, MA, USA.
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8
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Orellana EA, Liu Q, Yankova E, Pirouz M, De Braekeleer E, Zhang W, Lim J, Aspris D, Sendinc E, Garyfallos DA, Gu M, Ali R, Gutierrez A, Mikutis S, Bernardes GJL, Fischer ES, Bradley A, Vassiliou GS, Slack FJ, Tzelepis K, Gregory RI. METTL1-mediated m 7G modification of Arg-TCT tRNA drives oncogenic transformation. Mol Cell 2021; 81:3323-3338.e14. [PMID: 34352207 PMCID: PMC8380730 DOI: 10.1016/j.molcel.2021.06.031] [Citation(s) in RCA: 164] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 02/02/2021] [Accepted: 06/27/2021] [Indexed: 02/07/2023]
Abstract
The emerging "epitranscriptomics" field is providing insights into the biological and pathological roles of different RNA modifications. The RNA methyltransferase METTL1 catalyzes N7-methylguanosine (m7G) modification of tRNAs. Here we find METTL1 is frequently amplified and overexpressed in cancers and is associated with poor patient survival. METTL1 depletion causes decreased abundance of m7G-modified tRNAs and altered cell cycle and inhibits oncogenicity. Conversely, METTL1 overexpression induces oncogenic cell transformation and cancer. Mechanistically, we find increased abundance of m7G-modified tRNAs, in particular Arg-TCT-4-1, and increased translation of mRNAs, including cell cycle regulators that are enriched in the corresponding AGA codon. Accordingly, Arg-TCT expression is elevated in many tumor types and is associated with patient survival, and strikingly, overexpression of this individual tRNA induces oncogenic transformation. Thus, METTL1-mediated tRNA modification drives oncogenic transformation through a remodeling of the mRNA "translatome" to increase expression of growth-promoting proteins and represents a promising anti-cancer target.
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Affiliation(s)
- Esteban A Orellana
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Qi Liu
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Eliza Yankova
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Milner Therapeutics Institute, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK; Storm Therapeutics Ltd., Moneta Building (B280), Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Mehdi Pirouz
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Etienne De Braekeleer
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Wencai Zhang
- Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Jihoon Lim
- Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Demetrios Aspris
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Karaiskakio Foundation, Nicandrou Papamina Avenue, 2032 Nicosia, Cyprus
| | - Erdem Sendinc
- Division of Newborn Medicine and Epigenetics Program, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Dimitrios A Garyfallos
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK
| | - Muxin Gu
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK
| | - Raja Ali
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Alejandro Gutierrez
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Sigitas Mikutis
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Gonçalo J L Bernardes
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Eric S Fischer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Allan Bradley
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK
| | - George S Vassiliou
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Karaiskakio Foundation, Nicandrou Papamina Avenue, 2032 Nicosia, Cyprus; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK
| | - Frank J Slack
- Department of Pathology, Cancer Center, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; Harvard Initiative for RNA Medicine, Boston, MA 02115, USA
| | - Konstantinos Tzelepis
- Haematological Cancer Genetics, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK; Milner Therapeutics Institute, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK; Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, UK.
| | - Richard I Gregory
- Stem Cell Program, Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Division of Hematology/Oncology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; Harvard Initiative for RNA Medicine, Boston, MA 02115, USA.
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9
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Wang Y, Guan X, Zhang S, Liu Y, Wang S, Fan P, Du X, Yan S, Zhang P, Chen HY, Li W, Zhang D, Huang S. Structural-profiling of low molecular weight RNAs by nanopore trapping/translocation using Mycobacterium smegmatis porin A. Nat Commun 2021; 12:3368. [PMID: 34099723 PMCID: PMC8185011 DOI: 10.1038/s41467-021-23764-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 05/06/2021] [Indexed: 12/15/2022] Open
Abstract
Folding of RNA can produce elaborate tertiary structures, corresponding to their diverse roles in the regulation of biological activities. Direct observation of RNA structures at high resolution in their native form however remains a challenge. The large vestibule and the narrow constriction of a Mycobacterium smegmatis porin A (MspA) suggests a sensing mode called nanopore trapping/translocation, which clearly distinguishes between microRNA, small interfering RNA (siRNA), transfer RNA (tRNA) and 5 S ribosomal RNA (rRNA). To further profit from the acquired event characteristics, a custom machine learning algorithm is developed. Events from measurements with a mixture of RNA analytes can be automatically classified, reporting a general accuracy of ~93.4%. tRNAs, which possess a unique tertiary structure, report a highly distinguishable sensing feature, different from all other RNA types tested in this study. With this strategy, tRNAs from different sources are measured and a high structural conservation across different species is observed in single molecule.
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MESH Headings
- Machine Learning
- MicroRNAs/chemistry
- MicroRNAs/genetics
- MicroRNAs/metabolism
- Molecular Dynamics Simulation
- Molecular Weight
- Mycobacterium smegmatis/genetics
- Mycobacterium smegmatis/metabolism
- Nanopores
- Nucleic Acid Conformation
- Porins/chemistry
- Porins/genetics
- Porins/metabolism
- RNA/chemistry
- RNA/genetics
- RNA/metabolism
- RNA Folding
- RNA Transport
- RNA, Ribosomal, 5S/chemistry
- RNA, Ribosomal, 5S/genetics
- RNA, Ribosomal, 5S/metabolism
- RNA, Small Interfering/chemistry
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
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Affiliation(s)
- Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Xiaoyu Guan
- College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, MIIT Key Laboratory of Pattern Analysis and Machine Intelligence, Nanjing, China
| | - Shanyu Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Yao Liu
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Sha Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Pingping Fan
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Xiaoyu Du
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Shuanghong Yan
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Wenfei Li
- Collaborative Innovation Center of Advanced Microstructures, National Laboratory of Solid State Microstructure, Department of Physics, Nanjing University, Nanjing, China
| | - Daoqiang Zhang
- College of Computer Science and Technology, Nanjing University of Aeronautics and Astronautics, MIIT Key Laboratory of Pattern Analysis and Machine Intelligence, Nanjing, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, China
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10
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Martínez-Giménez JA, Tabares-Seisdedos R. Possible Ancestral Functions of the Genetic and RNA Operational Precodes and the Origin of the Genetic System. ORIGINS LIFE EVOL B 2021; 51:167-183. [PMID: 34097191 DOI: 10.1007/s11084-021-09610-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/17/2021] [Indexed: 11/24/2022]
Abstract
The origin of genetic systems is the central problem in the study of the origin of life for which various explanatory hypotheses have been presented. One model suggests that both ancestral transfer ribonucleic acid (tRNA) molecules and primitive ribosomes were originally involved in RNA replication (Campbell 1991). According to this model the early tRNA molecules catalyzed their own self-loading with a trinucleotide complementary to their anticodon triplet, while the primordial ribosome (protoribosome) catalyzed the transfer of these terminal trinucleotides from one tRNA to another tRNA harboring the growing RNA polymer at the 3´-end.Here we present the notion that the anticodon-codon-like pairs presumably located in the acceptor stem of primordial tRNAs (Rodin et al. 1996) (thus being and remaining, after the code and translation origins, the major contributor to the RNA operational code (Schimmel et al. 1993)) might have originally been used for RNA replication rather than translation; these anticodon and acceptor stem triplets would have been involved in accurately loading the 3'-end of tRNAs with a trinucleotide complementary to their anticodon triplet, thus allowing the accurate repair of tRNAs for their use by the protoribosome during RNA replication.We propose that tRNAs could have catalyzed their own trinucleotide self-loading by forming catalytic tRNA dimers which would have had polymerase activity. Therefore, the loading mechanism and its evolution may have been a basic step in the emergence of new genetic mechanisms such as genetic translation. The evolutionary implications of this proposed loading mechanism are also discussed.
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Affiliation(s)
| | - Rafael Tabares-Seisdedos
- Departamento de Medicina, Facultad de Medicina de Valencia, Universidad de Valencia, Av. Blasco Ibañez 17, 46010, Valencia, Spain.
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11
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Seelam Prabhakar P, Takyi NA, Wetmore SD. Posttranscriptional modifications at the 37th position in the anticodon stem-loop of tRNA: structural insights from MD simulations. RNA (NEW YORK, N.Y.) 2021; 27:202-220. [PMID: 33214333 PMCID: PMC7812866 DOI: 10.1261/rna.078097.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 11/16/2020] [Indexed: 06/11/2023]
Abstract
Transfer RNA (tRNA) is the most diversely modified RNA. Although the strictly conserved purine position 37 in the anticodon stem-loop undergoes modifications that are phylogenetically distributed, we do not yet fully understand the roles of these modifications. Therefore, molecular dynamics simulations are used to provide molecular-level details for how such modifications impact the structure and function of tRNA. A focus is placed on three hypermodified base families that include the parent i6A, t6A, and yW modifications, as well as derivatives. Our data reveal that the hypermodifications exhibit significant conformational flexibility in tRNA, which can be modulated by additional chemical functionalization. Although the overall structure of the tRNA anticodon stem remains intact regardless of the modification considered, the anticodon loop must rearrange to accommodate the bulky, dynamic hypermodifications, which includes changes in the nucleotide glycosidic and backbone conformations, and enhanced or completely new nucleobase-nucleobase interactions compared to unmodified tRNA or tRNA containing smaller (m1G) modifications at the 37th position. Importantly, the extent of the changes in the anticodon loop is influenced by the addition of small functional groups to parent modifications, implying each substituent can further fine-tune tRNA structure. Although the dominant conformation of the ASL is achieved in different ways for each modification, the molecular features of all modified tRNA drive the ASL domain to adopt the functional open-loop conformation. Importantly, the impact of the hypermodifications is preserved in different sequence contexts. These findings highlight the likely role of regulating mRNA structure and translation.
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MESH Headings
- Adenosine/analogs & derivatives
- Adenosine/metabolism
- Anticodon/chemistry
- Anticodon/genetics
- Anticodon/metabolism
- Base Pairing
- Base Sequence
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Isopentenyladenosine/chemistry
- Isopentenyladenosine/metabolism
- Molecular Dynamics Simulation
- Nucleic Acid Conformation
- Nucleosides/chemistry
- Nucleosides/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Transfer, Lys/chemistry
- RNA, Transfer, Lys/genetics
- RNA, Transfer, Lys/metabolism
- RNA, Transfer, Phe/chemistry
- RNA, Transfer, Phe/genetics
- RNA, Transfer, Phe/metabolism
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Affiliation(s)
- Preethi Seelam Prabhakar
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Nathania A Takyi
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
| | - Stacey D Wetmore
- Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta T1K 3M4, Canada
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12
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Monajemi H, M Zain S, Wan Abdullah WAT. A new step in kinetic proofreading due to misacylated-tRNA during ribosomal peptide bond formation. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2021; 40:635-646. [PMID: 34047250 DOI: 10.1080/15257770.2021.1923742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 04/03/2021] [Accepted: 04/26/2021] [Indexed: 10/21/2022]
Abstract
The translational accuracy in protein synthesis is contributed to by several mechanisms in the ribosome, generally called kinetic proofreading. This process in the ribosome inhibits the non-cognate codon-anticodon interaction. However, it is not sufficient for fidelity of protein synthesis since a wrong amino acid can easily be added to the growing polypeptide chain if a tRNA while cognate to the mRNA, carries a non-cognate amino acid. Therefore, additional to the kinetic proofreading, there must be some hitherto unknown characteristic in misacylated-tRNAs to stop the process of protein synthesis if such misacylated-tRNA is accommodated in the ribosomal A-site. In order to understand this characteristic, we have performed computational quantum chemistry analysis on five different tRNA molecules, each one attached to five different amino acids with one being cognate to the tRNA and the other four non-cognate. This study shows the importance of aminoacyl-tRNA binding energy in ensuring fidelity of protein synthesis.
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Affiliation(s)
- Hadieh Monajemi
- Department of Chemistry, University of Malaya, Kuala Lumpur, Malaysia
- Data Intensive Computing Centre, Research & Innovation Complex, University of Malaya, Kuala Lumpur, Malaysia
- Department of Physics, University of Malaya, Kuala Lumpur, Malaysia
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13
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Brooks W. An Epigenetics-Based Hypothesis of Autoantigen Development in Systemic Lupus Erythematosus. EPIGENOMES 2020; 4:epigenomes4020006. [PMID: 34968240 PMCID: PMC8594704 DOI: 10.3390/epigenomes4020006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/20/2020] [Indexed: 11/16/2022] Open
Abstract
Currently, we have a limited understanding of mechanisms leading to systemic lupus erythematosus, but we know that genetics, environmental factors, and epigenetics contribute to the disease. One common aspect of the various environmental triggers is that they can cause cellular stress. When extraordinary stress occurs, such as viral activation, a cell's response can include increased nucleolar volume and activity to produce more machinery (e.g., ribosomes) to help the cell recover. However, nucleolar expansion can disrupt the epigenetic control in neighboring heterochromatin that comprises the nucleolar shell. This disruption can open underlying vulnerabilities that provoke an autoimmune reaction. Here, we review the "X chromosome-nucleolus nexus" hypothesis, which explains how nucleolar stress can disrupt epigenetically silenced chromatin, especially the neighboring inactive X chromosome (aka the nucleolar satellite). Chromatin disruption can lead to the expression of sequestered DNA, such as Alu elements and fully functional LINE-1 reverse transcriptase genes. In addition, Alu transcripts can disrupt the nucleolar structural integrity, leading to nucleolar disintegration. Such disintegration can leave nucleolar components and products in autoantigenic forms, such as abnormal conformations or incomplete macromolecular assemblies. Recent research on DNA sensing pathways can now be incorporated into the hypothesis to provide further details explaining how autoantibodies to endogenous nucleic acids arise.
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Affiliation(s)
- Wesley Brooks
- Department of Chemistry, University of South Florida, Tampa, FL 33620, USA
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14
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Abstract
RNA is a functionally rich and diverse biomaterial responsible for regulating several cellular processes. This functionality has been harnessed to build predominately small nanoscale structures for drug delivery and the treatment of disease. The understanding of design principles to build large RNA structures will allow for further control of stoichiometry and spatial arrangement drugs and ligands. We present the design and characterization of RNA nanotubes that self-assemble from programmable monomers, or tiles, formed by five distinct RNA strands. Tiles include double crossover junctions and assemble via single-stranded sticky-end domains. We find that nanotube formation is dependent on the intertile crossover distance. The average length observed for the annealed RNA nanotubes is ≈1.5 μm, with many nanotubes exceeding 10 μm, enabling the characterization of RNA nanotubes length distribution via fluorescence microscopy. Assembled tubes were observed to be stable for more than 24 h, however post-annealing growth under isothermal conditions does not occur. Nanotubes assemble also from RNA tiles modified to include a single-stranded overhang (toehold), suggesting that it may be possible to decorate these large RNA scaffolds with nanoparticles or other nucleic acid molecules.
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Affiliation(s)
- Jaimie Marie Stewart
- Department of Bioengineering , University of California at Riverside , Riverside , California 92521 , United States
| | - Cody Geary
- Department of Bioengineering , California Institute of Technology , Pasadena , California 91125 , United States
- Interdisciplinary Nanoscience Center , Aarhus University , Aarhus C 08000 , Denmark
| | - Elisa Franco
- Department of Mechanical Engineering , University of California at Riverside , Riverside , California 92521 , United States
- Department of Mechanical and Aerospace Engineering , University of California , Los Angeles , California 90095 , United States
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15
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Hexahydrated Mg 2+ Binding and Outer-Shell Dehydration on RNA Surface. Biophys J 2019; 114:1274-1284. [PMID: 29590585 DOI: 10.1016/j.bpj.2018.01.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 10/17/2022] Open
Abstract
The interaction between metal ions, especially Mg2+ ions, and RNA plays a critical role in RNA folding. Upon binding to RNA, a metal ion that is fully hydrated in bulk solvent can become dehydrated. Here we use molecular dynamics simulation to investigate the dehydration of bound hexahydrated Mg2+ ions. We find that a hydrated Mg2+ ion in the RNA groove region can involve significant dehydration in the outer hydration shell. The first or innermost hydration shell of the Mg2+ ion, however, is retained during the simulation because of the strong ion-water electrostatic attraction. As a result, water-mediated hydrogen bonding remains an important form for Mg2+-RNA interaction. Analysis for ions at different binding sites shows that the most pronounced water deficiency relative to the fully hydrated state occurs at a radial distance of around 11 Å from the center of the ion. Based on the independent 200 ns molecular dynamics simulations for three different RNA structures (Protein Data Bank: 1TRA, 2TPK, and 437D), we find that Mg2+ ions overwhelmingly dominate over monovalent ions such as Na+ and K+ in ion-RNA binding. Furthermore, application of the free energy perturbation method leads to a quantitative relationship between the Mg2+ dehydration free energy and the local structural environment. We find that ΔΔGhyd, the change of the Mg2+ hydration free energy upon binding to RNA, varies linearly with the inverse distance between the Mg2+ ion and the nearby nonbridging oxygen atoms of the phosphate groups, and ΔΔGhyd can reach -2.0 kcal/mol and -3.0 kcal/mol for an Mg2+ ion bound to the surface and to the groove interior, respectively. In addition, the computation results in an analytical formula for the hydration ratio as a function of the average inverse Mg2+-O distance. The results here might be useful for further quantitative investigations of ion-RNA interactions in RNA folding.
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16
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Leonarski F, D'Ascenzo L, Auffinger P. Nucleobase carbonyl groups are poor Mg 2+ inner-sphere binders but excellent monovalent ion binders-a critical PDB survey. RNA (NEW YORK, N.Y.) 2019; 25:173-192. [PMID: 30409785 PMCID: PMC6348993 DOI: 10.1261/rna.068437.118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 10/16/2018] [Indexed: 05/04/2023]
Abstract
Precise knowledge of Mg2+ inner-sphere binding site properties is vital for understanding the structure and function of nucleic acid systems. Unfortunately, the PDB, which represents the main source of Mg2+ binding sites, contains a substantial number of assignment issues that blur our understanding of the functions of these ions. Here, following a previous study devoted to Mg2+ binding to nucleobase nitrogens, we surveyed nucleic acid X-ray structures from the PDB with resolutions ≤2.9 Å to classify the Mg2+ inner-sphere binding patterns to nucleotide carbonyl, ribose hydroxyl, cyclic ether, and phosphodiester oxygen atoms. From this classification, we derived a set of "prior-knowledge" nucleobase Mg2+ binding sites. We report that crystallographic examples of trustworthy nucleobase Mg2+ binding sites are fewer than expected since many of those are associated with misidentified Na+ or K+ We also emphasize that binding of Na+ and K+ to nucleic acids is much more frequent than anticipated. Overall, we provide evidence derived from X-ray structures that nucleobases are poor inner-sphere binders for Mg2+ but good binders for monovalent ions. Based on strict stereochemical criteria, we propose an extended set of guidelines designed to help in the assignment and validation of ions directly contacting nucleobase and ribose atoms. These guidelines should help in the interpretation of X-ray and cryo-EM solvent density maps. When borderline Mg2+ stereochemistry is observed, alternative placement of Na+, K+, or Ca2+ must be considered. We also critically examine the use of lanthanides (Yb3+, Tb3+) as Mg2+ substitutes in crystallography experiments.
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Affiliation(s)
- Filip Leonarski
- Swiss Light Source, Paul Scherrer Institut, Villigen PSI, 5232, Switzerland
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, 67084, France
| | - Luigi D'Ascenzo
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, 67084, France
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Pascal Auffinger
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, Strasbourg, 67084, France
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17
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Mettl1/Wdr4-Mediated m 7G tRNA Methylome Is Required for Normal mRNA Translation and Embryonic Stem Cell Self-Renewal and Differentiation. Mol Cell 2018; 71:244-255.e5. [PMID: 29983320 DOI: 10.1016/j.molcel.2018.06.001] [Citation(s) in RCA: 269] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/25/2018] [Accepted: 05/31/2018] [Indexed: 01/01/2023]
Abstract
tRNAs are subject to numerous modifications, including methylation. Mutations in the human N7-methylguanosine (m7G) methyltransferase complex METTL1/WDR4 cause primordial dwarfism and brain malformation, yet the molecular and cellular function in mammals is not well understood. We developed m7G methylated tRNA immunoprecipitation sequencing (MeRIP-seq) and tRNA reduction and cleavage sequencing (TRAC-seq) to reveal the m7G tRNA methylome in mouse embryonic stem cells (mESCs). A subset of 22 tRNAs is modified at a "RAGGU" motif within the variable loop. We observe increased ribosome occupancy at the corresponding codons in Mettl1 knockout mESCs, implying widespread effects on tRNA function, ribosome pausing, and mRNA translation. Translation of cell cycle genes and those associated with brain abnormalities is particularly affected. Mettl1 or Wdr4 knockout mESCs display defective self-renewal and neural differentiation. Our study uncovers the complexity of the mammalian m7G tRNA methylome and highlights its essential role in ESCs with links to human disease.
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18
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Brooks WH. A Review of Autoimmune Disease Hypotheses with Introduction of the "Nucleolus" Hypothesis. Clin Rev Allergy Immunol 2018; 52:333-350. [PMID: 27324247 DOI: 10.1007/s12016-016-8567-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Numerous hypotheses have been proposed in order to explain the complexity of autoimmune diseases. These hypotheses provide frameworks towards understanding the relations between triggers, autoantigen development, symptoms, and demographics. However, testing and refining these hypotheses are difficult tasks since autoimmune diseases have a potentially overwhelming number of variables due to the influence on autoimmune diseases from environmental factors, genetics, and epigenetics. Typically, the hypotheses are narrow in scope, for example, explaining the diseases in terms of genetics without defining detailed roles for environmental factors or epigenetics. Here, we present a brief review of the major hypotheses of autoimmune diseases including a new one related to the consequences of abnormal nucleolar interactions with chromatin, the "nucleolus" hypothesis which was originally termed the "inactive X chromosome and nucleolus nexus" hypothesis. Indeed, the dynamic nucleolus can expand as part of a cellular stress response and potentially engulf portions of chromatin, leading to disruption of the chromatin. The inactive X chromosome (a.k.a. the Barr body) is particularly vulnerable due to its close proximity to the nucleolus. In addition, the polyamines, present at high levels in the nucleolus, are also suspected of contributing to the development of autoantigens.
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Affiliation(s)
- Wesley H Brooks
- Department of Chemistry, University of South Florida, 4202 E Fowler Ave, CHE205, Tampa, FL, 33620, USA.
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19
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Moore PB. Structural biology: Past, present, and future. N Biotechnol 2017; 38:29-35. [PMID: 27498255 DOI: 10.1016/j.nbt.2016.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 07/19/2016] [Indexed: 11/19/2022]
Abstract
In March 2014, a symposium was held at Aarhus University to commemorate the 40th anniversary of the founding of its Division of Biostructural Chemistry by Professor Brian Clark. This article is a lightly edited version of the talk the author gave to open that event. It consists of some reflections about the discipline known as structural biology, and some comments about the author's interactions with Professor Clark and the Division of Biostructural Chemistry over the years.
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Affiliation(s)
- Peter B Moore
- Department of Chemistry, Yale University, PO Box 208107, New Haven, CT, USA.
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20
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Myka KK, Hawkins M, Syeda AH, Gupta MK, Meharg C, Dillingham MS, Savery NJ, Lloyd RG, McGlynn P. Inhibiting translation elongation can aid genome duplication in Escherichia coli. Nucleic Acids Res 2017; 45:2571-2584. [PMID: 27956500 PMCID: PMC5389703 DOI: 10.1093/nar/gkw1254] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/28/2016] [Accepted: 12/01/2016] [Indexed: 12/28/2022] Open
Abstract
Conflicts between replication and transcription challenge chromosome duplication. Escherichia coli replisome movement along transcribed DNA is promoted by Rep and UvrD accessory helicases with Δrep ΔuvrD cells being inviable under rapid growth conditions. We have discovered that mutations in a tRNA gene, aspT, in an aminoacyl tRNA synthetase, AspRS, and in a translation factor needed for efficient proline-proline bond formation, EF-P, suppress Δrep ΔuvrD lethality. Thus replication-transcription conflicts can be alleviated by the partial sacrifice of a mechanism that reduces replicative barriers, namely translating ribosomes that reduce RNA polymerase backtracking. Suppression depends on RelA-directed synthesis of (p)ppGpp, a signalling molecule that reduces replication-transcription conflicts, with RelA activation requiring ribosomal pausing. Levels of (p)ppGpp in these suppressors also correlate inversely with the need for Rho activity, an RNA translocase that can bind to emerging transcripts and displace transcription complexes. These data illustrate the fine balance between different mechanisms in facilitating gene expression and genome duplication and demonstrate that accessory helicases are a major determinant of this balance. This balance is also critical for other aspects of bacterial survival: the mutations identified here increase persistence indicating that similar mutations could arise in naturally occurring bacterial populations facing antibiotic challenge.
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Affiliation(s)
- Kamila K. Myka
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Michelle Hawkins
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Aisha H. Syeda
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Milind K. Gupta
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Caroline Meharg
- Institute for Global Food Security, Queen's University Belfast, David Keir Building, Malone Road, Belfast BT9 5BN, UK
| | - Mark S. Dillingham
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8, 1TD, UK
| | - Nigel J. Savery
- DNA-Protein Interactions Unit, School of Biochemistry, University of Bristol, Bristol BS8, 1TD, UK
| | - Robert G. Lloyd
- Centre for Genetics and Genomics, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Peter McGlynn
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
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21
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Leonarski F, D'Ascenzo L, Auffinger P. Mg2+ ions: do they bind to nucleobase nitrogens? Nucleic Acids Res 2017; 45:987-1004. [PMID: 27923930 PMCID: PMC5314772 DOI: 10.1093/nar/gkw1175] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 01/28/2023] Open
Abstract
Given the many roles proposed for Mg2+ in nucleic acids, it is essential to accurately determine their binding modes. Here, we surveyed the PDB to classify Mg2+ inner-sphere binding patterns to nucleobase imine N1/N3/N7 atoms. Among those, purine N7 atoms are considered to be the best nucleobase binding sites for divalent metals. Further, Mg2+ coordination to N7 has been implied in several ribozyme catalytic mechanisms. We report that Mg2+ assigned near imine nitrogens derive mostly from poor interpretations of electron density patterns and are most often misidentified Na+, K+, NH4+ ions, water molecules or spurious density peaks. Consequently, apart from few documented exceptions, Mg2+ ions do not bind to N7 atoms. Without much of a surprise, Mn2+, Zn2+ and Cd2+, which have a higher affinity for nitrogens, may contact N7 atoms when present in crystallization buffers. In this respect, we describe for the first time a potential Zn2+ ribosomal binding site involving two purine N7 atoms. Further, we provide a set of guidelines to help in the assignment of Mg2+ in crystallographic, cryo-EM, NMR and model building practices and discuss implications of our findings related to ion substitution experiments.
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Affiliation(s)
- Filip Leonarski
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Luigi D'Ascenzo
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
| | - Pascal Auffinger
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR9002, F-67000 Strasbourg, France
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22
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Barciszewska MZ, Perrigue PM, Barciszewski J. tRNA--the golden standard in molecular biology. MOLECULAR BIOSYSTEMS 2016; 12:12-7. [PMID: 26549858 DOI: 10.1039/c5mb00557d] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Transfer RNAs (tRNAs) represent a major class of RNA molecules. Their primary function is to help decode a messenger RNA (mRNA) sequence in order to synthesize protein and thus ensures the precise translation of genetic information that is imprinted in DNA. The discovery of tRNA in the late 1950's provided critical insight into a genetic machinery when little was known about the central dogma of molecular biology. In 1965, Robert Holley determined the first nucleotide sequence of alanine transfer RNA (tRNA(Ala)) which earned him the 1968 Nobel Prize in Physiology or Medicine. Today, tRNA is one of the best described and characterized biological molecules. Here we review some of the key historical events in tRNA research which led to breakthrough discoveries and new developments in molecular biology.
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Affiliation(s)
- Mirosława Z Barciszewska
- Institute of Bioorganic Chemistry of the Polish Academy of Sciences, Noskowskiego 12, 61-704 Poznań, Poland.
| | - Patrick M Perrigue
- Institute of Bioorganic Chemistry of the Polish Academy of Sciences, Noskowskiego 12, 61-704 Poznań, Poland.
| | - Jan Barciszewski
- Institute of Bioorganic Chemistry of the Polish Academy of Sciences, Noskowskiego 12, 61-704 Poznań, Poland.
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23
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Dyubankova N, Sochacka E, Kraszewska K, Nawrot B, Herdewijn P, Lescrinier E. Contribution of dihydrouridine in folding of the D-arm in tRNA. Org Biomol Chem 2015; 13:4960-6. [PMID: 25815904 DOI: 10.1039/c5ob00164a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Posttranscriptional modifications of transfer RNAs (tRNAs) are proven to be critical for all core aspects of tRNA function. While the majority of tRNA modifications were discovered in the 1970s, their contribution in tRNA folding, stability, and decoding often remains elusive. In this work an NMR study was performed to obtain more insight in the role of the dihydrouridine (D) modification in the D-arm of tRNAi(Met) from S. pombe. While the unmodified oligonucleotide adopted several undefined conformations that interconvert in solution, the presence of a D nucleoside triggered folding into a hairpin with a stable stem and flexible loop region. Apparently the D modification is required in the studied sequence to fold into a stable hairpin. Therefore we conclude that D contributes to the correct folding and stability of D-arm in tRNA. In contrast to what is generally assumed for nucleic acids, the sharp 'imino' signal for the D nucleobase at 10 ppm in 90% H2O is not indicative for the presence of a stable hydrogen bond. The strong increase in pKa upon loss of the aromatic character in the modified nucleobase slows down the exchange of its 'imino' proton significantly, allowing its observation even in an isolated D nucleoside in 90% H2O in acidic to neutral conditions.
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Affiliation(s)
- N Dyubankova
- Medicinal Chemistry, Department of Pharmaceutical Sciences, Rega Institute for Medical Research, KU Leuven, Minderbroedersstraat 10, 3000 Leuven, Belgium.
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24
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Brooks WH, Renaudineau Y. Epigenetics and autoimmune diseases: the X chromosome-nucleolus nexus. Front Genet 2015; 6:22. [PMID: 25763008 PMCID: PMC4329817 DOI: 10.3389/fgene.2015.00022] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 01/16/2015] [Indexed: 12/18/2022] Open
Abstract
Autoimmune diseases occur more often in females, suggesting a key role for the X chromosome. X chromosome inactivation, a major epigenetic feature in female cells that provides dosage compensation of X-linked genes to avoid overexpression, presents special vulnerabilities that can contribute to the disease process. Disruption of X inactivation can result in loss of dosage compensation with expression from previously sequestered genes, imbalance of gene products, and altered endogenous material out of normal epigenetic context. In addition, the human X has significant differences compared to other species and these differences can contribute to the frequency and intensity of the autoimmune disease in humans as well as the types of autoantigens encountered. Here a link is demonstrated between autoimmune diseases, such as systemic lupus erythematosus, and the X chromosome by discussing cases in which typically non-autoimmune disorders complicated with X chromosome abnormalities also present lupus-like symptoms. The discussion is then extended to the reported spatial and temporal associations of the inactive X chromosome with the nucleolus. When frequent episodes of cellular stress occur, the inactive X chromosome may be disrupted and inadvertently become involved in the nucleolar stress response. Development of autoantigens, many of which are at least transiently components of the nucleolus, is then described. Polyamines, which aid in nucleoprotein complex assembly in the nucleolus, increase further during cell stress, and appear to have an important role in the autoimmune disease process. Autoantigenic endogenous material can potentially be stabilized by polyamines. This presents a new paradigm for autoimmune diseases: that many are antigen-driven and the autoantigens originate from altered endogenous material due to episodes of cellular stress that disrupt epigenetic control. This suggests that epigenetics and the X chromosome are important aspects of autoimmune diseases.
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Affiliation(s)
- Wesley H Brooks
- Department of Chemistry, University of South Florida Tampa, FL, USA
| | - Yves Renaudineau
- Research Unit INSERM ERI29/EA2216, SFR ScinBios, Labex Igo "Immunotherapy Graft, Oncology", Réseau Épigénétique et Réseau Canaux Ioniques du Cancéropole Grand Ouest, European University of Brittany Brest, France ; Laboratory of Immunology and Immunotherapy, Hôpital Morvan Brest, France
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25
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Abstract
Recent progress with techniques for monitoring RNA structure in cells such as ‘DMS-Seq’ and ‘Structure-Seq’ suggests that a new era of RNA structure-function exploration is on the horizon. This will also include systematic investigation of the factors required for the structural integrity of RNA. In this context, much evidence accumulated over 50 years suggests that polyamines play important roles as modulators of RNA structure. Here, we summarize and discuss recent literature relating to the roles of these small endogenous molecules in RNA function. We have included studies directed at understanding the binding interactions of polyamines with polynucleotides, tRNA, rRNA, mRNA and ribozymes using chemical, biochemical and spectroscopic tools. In brief, polyamines bind RNA in a sequence-selective fashion and induce changes in RNA structure in context-dependent manners. In some cases the functional consequences of these interactions have been observed in cells. Most notably, polyamine-mediated effects on RNA are frequently distinct from those of divalent cations (i.e. Mg2+) confirming their roles as independent molecular entities which help drive RNA-mediated processes.
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Affiliation(s)
- Helen L Lightfoot
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zürich, CH-8093, Zürich, Switzerland
| | - Jonathan Hall
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zürich, CH-8093, Zürich, Switzerland
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26
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Wu S, Chen Y, Mao G, Trobro S, Kwiatkowski M, Kirsebom LA. Transition-state stabilization in Escherichia coli ribonuclease P RNA-mediated cleavage of model substrates. Nucleic Acids Res 2014; 42:631-42. [PMID: 24097434 PMCID: PMC3874170 DOI: 10.1093/nar/gkt853] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 01/10/2023] Open
Abstract
We have used model substrates carrying modified nucleotides at the site immediately 5' of the canonical RNase P cleavage site, the -1 position, to study Escherichia coli RNase P RNA-mediated cleavage. We show that the nucleobase at -1 is not essential but its presence and identity contribute to efficiency, fidelity of cleavage and stabilization of the transition state. When U or C is present at -1, the carbonyl oxygen at C2 on the nucleobase contributes to transition-state stabilization, and thus acts as a positive determinant. For substrates with purines at -1, an exocyclic amine at C2 on the nucleobase promotes cleavage at an alternative site and it has a negative impact on cleavage at the canonical site. We also provide new insights into the interaction between E. coli RNase P RNA and the -1 residue in the substrate. Our findings will be discussed using a model where bacterial RNase P cleavage proceeds through a conformational-assisted mechanism that positions the metal(II)-activated H2O for an in-line attack on the phosphorous atom that leads to breakage of the phosphodiester bond.
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Affiliation(s)
- Shiying Wu
- Department of Cell and Molecular Biology, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA and Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden
| | - Yu Chen
- Department of Cell and Molecular Biology, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA and Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden
| | - Guanzhong Mao
- Department of Cell and Molecular Biology, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA and Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden
| | - Stefan Trobro
- Department of Cell and Molecular Biology, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA and Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden
| | - Marek Kwiatkowski
- Department of Cell and Molecular Biology, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA and Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden
| | - Leif A. Kirsebom
- Department of Cell and Molecular Biology, Box 596, Uppsala University, SE-751 24 Uppsala, Sweden, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA and Department of Molecular Biology, Swedish University of Agricultural Sciences, Box 590, SE-751 24 Uppsala, Sweden
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27
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Hayashi Y, Sugiyama H, Suganami A, Higashi K, Kashiwagi K, Igarashi K, Kawauchi S, Tamura Y. Prediction of the interaction between spermidine and the G-G mismatch containing acceptor stem in tRNA(Ile): molecular modeling, density functional theory, and molecular dynamics study. Biochem Biophys Res Commun 2013; 441:999-1004. [PMID: 24239547 DOI: 10.1016/j.bbrc.2013.11.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 11/03/2013] [Indexed: 11/26/2022]
Abstract
Polyamines, putrescine, spermidine (SPD), and spermine are closely linked to cell growth, and highly regulate the levels of transcription, translation and protein turnover. We propose that SPD stimulates the formation of Ile-tRNA(Ile) by inducing a selective structural change of the G-G mismatch containing acceptor stem in tRNA(Ile). Here, we provide insight into how SPD recognizes and stabilizes the G-G mismatch containing acceptor stem in tRNA(Ile) with molecular modeling (MM), density functional theory (DFT) calculations, and molecular dynamics (MD) simulations. The results of the MM and DFT calculations indicate that the negatively charged region of the G-G mismatch containing acceptor stem in tRNA(Ile) is preferentially recognized by positively charged SPD. In addition, MD simulations indicate that all of the positively charged amino groups of SPD under physiological conditions (N1(NH3(+)), N5(NH2(+)), and N10(NH3(+)) could form hydrogen bonds with tRNA(Ile) and trigger the SPD-induced stabilization and structural change of the G-G mismatch containing acceptor stem in tRNA(Ile). Thus, this approach should be useful for determining the preferential binding site and appropriate binding mode of polyamines on tRNA(Ile).
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Affiliation(s)
- Yoshihiro Hayashi
- Department of Organic and Polymeric Materials, Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo 152-8522, Japan
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28
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Witts RN, Hopson EC, Koballa DE, Van Boening TA, Hopkins NH, Patterson EV, Nagan MC. Backbone-base interactions critical to quantum stabilization of transfer RNA anticodon structure. J Phys Chem B 2013; 117:7489-97. [PMID: 23742318 DOI: 10.1021/jp400084p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Transfer RNA (tRNA) anticodons adopt a highly ordered 3'-stack without significant base overlap. Density functional theory at the M06-2X/6-31+G(d,p) level in combination with natural bond orbital analysis was utilized to calculate the intramolecular interactions within the tRNA anticodon that are responsible for stabilizing the stair-stepped conformation. Ten tRNA X-ray crystal structures were obtained from the PDB databank and were trimmed to include only the anticodon bases. Hydrogenic positions were added and optimized for the structures in the stair-stepped conformation. The sugar-phosphate backbone has been retained for these calculations, revealing the role it plays in RNA structural stability. It was found that electrostatic interactions between the sugar-phosphate backbone and the base provide the most stability, rather than the traditionally studied interbase stacking. Base-stacking interactions, though present, were weak and inconsistent. Aqueous solvation was found to have little effect on the intramolecular interactions.
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Affiliation(s)
- Rachel N Witts
- Department of Chemistry, Truman State University, 100 East Normal, Kirksville, Missouri 63501, USA
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29
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Kimoto M, Hikida Y, Hirao I. Site-Specific Functional Labeling of Nucleic Acids by In Vitro Replication and Transcription using Unnatural Base Pair Systems. Isr J Chem 2013. [DOI: 10.1002/ijch.201300013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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30
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Anderson M, Schultz EP, Martick M, Scott WG. Active-site monovalent cations revealed in a 1.55-Å-resolution hammerhead ribozyme structure. J Mol Biol 2013; 425:3790-8. [PMID: 23711504 DOI: 10.1016/j.jmb.2013.05.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/20/2013] [Accepted: 05/21/2013] [Indexed: 11/18/2022]
Abstract
We have obtained a 1.55-Å crystal structure of a hammerhead ribozyme derived from Schistosoma mansoni under conditions that permit detailed observations of Na(+) ion binding in the ribozyme's active site. At least two such Na(+) ions are observed. The first Na(+) ion binds to the N7 of G10.1 and the adjacent A9 phosphate in a manner identical with that previously observed for divalent cations. A second Na(+) ion binds to the Hoogsteen face of G12, the general base in the hammerhead cleavage reaction, thereby potentially dissipating the negative charge of the catalytically active enolate form of the nucleotide base. A potential but more ambiguous third site bridges the A9 and scissile phosphates in a manner consistent with that of previous predictions. Hammerhead ribozymes have been observed to be active in the presence of high concentrations of monovalent cations, including Na(+), but the mechanism by which monovalent cations substitute for divalent cations in hammerhead catalysis remains unclear. Our results enable us to suggest that Na(+) directly and specifically substitutes for divalent cations in the hammerhead active site. The detailed geometry of the pre-catalytic active-site complex is also revealed with a new level of precision, thanks to the quality of the electron density maps obtained from what is currently the highest-resolution ribozyme structure in the Protein Data Bank.
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Affiliation(s)
- Michael Anderson
- Department of Chemistry and Biochemistry and The Center for the Molecular Biology of RNA, 228 Sinsheimer Laboratories, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
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31
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Monajemi H, Daud MN, Mohd Zain S, Wan Abdullah WAT. ONIOM and ab-initio calculations on the mechanism of uncatalyzed peptide bond formation. Biochem Cell Biol 2012; 90:691-700. [PMID: 23016605 DOI: 10.1139/o2012-027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Finding a proper transition structure for the peptide bond formation process can lead one to a better understanding of the role of ribosome in catalyzing this reaction. Using computer simulations, we performed the potential energy surface scan on the ester bond dissociation of P-site aminoacyl-tRNA and the peptide bond formation of P-site and A-site amino acids. The full fragments of initiator tRNA(i)(met) and elongator tRNA(phe) are attached to both cognate and non-cognate amino acids as the P-site substrate. The A-site amino acid for all four calculations is methionine. We used ONIOM calculations to reduce the computational cost. Our study illustrates the reduced rate of peptide bond formation for misacylated tRNA(i)(met) in the absence of ribosomal bases. The misacylated elongator tRNA(phe), however, did not show any difference in its PES compared with that for the phe-tRNA(phe). This demonstrates the structural specification of initiator tRNA(i)(met) for the amino acids side chain.
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Affiliation(s)
- Hadieh Monajemi
- Department of Physics, Faculty of Science, Universiti Malaya, 50603 Kuala Lumpur, Malaysia.
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32
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Giel-Pietraszuk M, Barciszewski J. Hydrostatic and osmotic pressure study of the RNA hydration. Mol Biol Rep 2012; 39:6309-18. [PMID: 22314910 PMCID: PMC3310992 DOI: 10.1007/s11033-012-1452-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Accepted: 01/23/2012] [Indexed: 11/17/2022]
Abstract
The tertiary structure of nucleic acids results from an equilibrium between electrostatic interactions of phosphates, stacking interactions of bases, hydrogen bonds between polar atoms and water molecules. Water interactions with ribonucleic acid play a key role in its structure formation, stabilization and dynamics. We used high hydrostatic pressure and osmotic pressure to analyze changes in RNA hydration. We analyzed the lead catalyzed hydrolysis of tRNAPhe from S. cerevisiae as well as hydrolytic activity of leadzyme. Pb(II) induced hydrolysis of the single phosphodiester bond in tRNAPhe is accompanied by release of 98 water molecules, while other molecule, leadzyme releases 86.
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Affiliation(s)
- Małgorzata Giel-Pietraszuk
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland.
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33
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Monajemi H, Omar NYM, Daud MN, Zain SM, Abdullah WATW. The role of initiator tRNAimet in fidelity of initiation of protein synthesis. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2012; 30:726-39. [PMID: 21902474 DOI: 10.1080/15257770.2011.605780] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The proper arrangement of amino acids in a protein determines its proper function, which is vital for the cellular metabolism. This indicates that the process of peptide bond formation requires high fidelity. One of the most important processes for this fidelity is kinetic proofreading. As biochemical experiments suggest that kinetic proofreading plays a major role in ensuring the fidelity of protein synthesis, it is not certain whether or not a misacylated tRNA would be corrected by kinetic proofreading during the peptide bond formation. Using 2-layered ONIOM (QM/MM) computational calculations, we studied the behavior of misacylated tRNAs and compared the results with these for cognate aminoacyl-tRNAs during the process of peptide bond formation to investigate the effect of nonnative amino acids on tRNAs. The difference between the behavior of initiator tRNA(i) (met) compared to the one for the elongator tRNAs indicates that only the initiator tRNA(i) (met) specifies the amino acid side chain.
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Affiliation(s)
- Hadieh Monajemi
- Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
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34
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Scott WG. Challenges and surprises that arise with nucleic acids during model building and refinement. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:441-5. [PMID: 22505264 PMCID: PMC3322603 DOI: 10.1107/s0907444912001084] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 01/10/2012] [Indexed: 11/11/2022]
Abstract
The process of building and refining crystal structures of nucleic acids, although similar to that for proteins, has some peculiarities that give rise to both various complications and various benefits. Although conventional isomorphous replacement phasing techniques are typically used to generate an experimental electron-density map for the purposes of determining novel nucleic acid structures, it is also possible to couple the phasing and model-building steps to permit the solution of complex and novel RNA three-dimensional structures without the need for conventional heavy-atom phasing approaches.
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Affiliation(s)
- William G Scott
- Department of Chemistry and Biochemistry and the Center for the Molecular Biology of RNA, University of California at Santa Cruz, Santa Cruz, CA 95064, USA.
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35
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Abstract
The purpose of Reflections articles, it seems, is to give elderly scientists a chance to write about the "good old days," when everyone walked to school in the snow. They enjoy this activity so much that your editor, Martha Fedor, must have known that I would accept her invitation to write such an article, no matter how much I demurred at first. As everyone knows, flattery will get you everywhere. It may comfort the apprehensive reader to learn that there is not going to be much walking to school in the snow in this story. On the contrary, rather than thinking how hard I had it during my scientific career, I find it inconceivable that anyone could have had a smoother ride. At the time I began my career, science was an expanding enterprise in the United States that welcomed the young. Only in such an opportunity-rich environment would someone like me have stood a chance. The contrast between that world and the dog-eat-dog world young scientists confront today is stark.
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Affiliation(s)
- Peter B Moore
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, USA.
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37
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Giegé R, Jühling F, Pütz J, Stadler P, Sauter C, Florentz C. Structure of transfer RNAs: similarity and variability. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 3:37-61. [DOI: 10.1002/wrna.103] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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38
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Odani A, Jastrzab R, Lomozik L. Equilibrium study on the interaction of phytic acid with polyamines and metal ions. Metallomics 2011; 3:735-43. [DOI: 10.1039/c1mt00031d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Towards a systems approach in the genetic analysis of archaea: Accelerating mutant construction and phenotypic analysis in Haloferax volcanii. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2010; 2010:426239. [PMID: 21234384 PMCID: PMC3017900 DOI: 10.1155/2010/426239] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 10/24/2010] [Indexed: 01/17/2023]
Abstract
With the availability of a genome sequence and increasingly sophisticated genetic tools, Haloferax volcanii is becoming a model for both Archaea and halophiles. In order for H. volcanii to reach a status equivalent to Escherichia coli, Bacillus subtilis, or Saccharomyces cerevisiae, a gene knockout collection needs to be constructed in order to identify the archaeal essential gene set and enable systematic phenotype screens. A streamlined gene-deletion protocol adapted for potential automation was implemented and used to generate 22 H. volcanii deletion strains and identify several potentially essential genes. These gene deletion mutants, generated in this and previous studies, were then analyzed in a high-throughput fashion to measure growth rates in different media and temperature conditions. We conclude that these high-throughput methods are suitable for a rapid investigation of an H. volcanii mutant library and suggest that they should form the basis of a larger genome-wide experiment.
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40
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Saxena S, Miyoshi D, Sugimoto N. Sole and stable RNA duplexes of G-rich sequences located in the 5'-untranslated region of protooncogenes. Biochemistry 2010; 49:7190-201. [PMID: 20672842 DOI: 10.1021/bi101093a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Guanine- (G-) rich nucleic acid sequences can form four-stranded structures called G-quadruplexes. It is widely held that the formation of a G-quadruplex in RNA is more feasible than in DNA because of the lack of a complementary strand in mRNA. Here, we analyzed sequences of 5'-untranslated regions of protooncogenes and surprisingly found that these regions showed an enrichment of not only guanine (G) but also cytosine (C) nucleotides. Since neighboring cytosine- (C-) rich regions can affect the formation and stability of a G-quadruplex structure, we further investigated the properties of DNA and RNA structures of G-rich and GC-rich regions. We selected typical GC-rich RNA sequences from protooncogenes and corresponding DNA sequences and investigated their structures. It was found that the GC-rich RNA sequences formed stable A-form duplexes as their major structure independent of the surrounding conditions, including the presence of different cations (Na(+), K(+), or Li(+)) or molecular crowding with 40 wt % poly(ethylene glycol) with an average molecular mass of 200 Da although there are a few exceptions in which only a combination of K(+) and molecular crowding induced a G-quadruplex structure of an extremely G-rich RNA sequence. In contrast, structural polymorphisms involving duplexes, G-quadruplexes, and i-motifs were observed for GC-rich DNA sequences depending on the surrounding factors. These results demonstrate the considerable structural and functional differences in GC-rich sequences of the genome (DNA) and transcriptosome (mRNA) with respect to the nucleic acid backbone. Moreover, it was suggested that structural study for a G-rich RNA sequence should be carried out under cell-mimicking condition where K(+) and crowding cosolutes exist.
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Affiliation(s)
- Sarika Saxena
- Frontier Institute for Biomolecular Engineering Research (FIBER), 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
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41
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Tamkovich NV, Zenkov AN, Vlasov VV, Zenkova MA. [An RNA sequence determines the speed of its splitting by artificial ribonucleases]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2010; 36:223-35. [PMID: 20531481 DOI: 10.1134/s106816201002010x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Phosphodiester bonds in RNA situated between similar nucleotides but in different sequences (context) were split under the action of artificial and natural ribonucleases with different speeds, and the reason for this phenomenon has not yet been fully revealed. In this study, the influence of one-nucleotide substitution on the sensitivity to splitting of the phosphodiester bonds in linear and structured RNA with homologous sequences is studied for the first time. It is indicated that the introduction of one-nucleotide substitution in the RNA sequence significantly (up to 10 times) changes the speed of the splitting of the bonds that are separated from the substitution point not only by 1-3, but also 6-8 nucleotides, by artificial ribonucleases. The observed regularities may be explained by the fact that the introduction of a one-nucleotide substitution significantly changes the stacking interactions and the net of hydrogen bonds in the RNA molecule. The applied value of this study consists of the ability of using low-molecular artificial ribonucleases with the aim of choosing the region of the binding of the oligonucleotide in the construction of a conjugate for the site-directed cutting of RNA, because the choice of a phosphodiester bond (motif) easily subjected to splitting significantly determines the effectiveness of artificial ribonucleases of directed action.
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Affiliation(s)
- N V Tamkovich
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent'eva 8, Novosibirsk, 630090 Russia
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42
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Byrne RT, Konevega AL, Rodnina MV, Antson AA. The crystal structure of unmodified tRNAPhe from Escherichia coli. Nucleic Acids Res 2010; 38:4154-62. [PMID: 20203084 PMCID: PMC2896525 DOI: 10.1093/nar/gkq133] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Post-transcriptional nucleoside modifications fine-tune the biophysical and biochemical properties of transfer RNA (tRNA) so that it is optimized for participation in cellular processes. Here we report the crystal structure of unmodified tRNAPhe from Escherichia coli at a resolution of 3 Å. We show that in the absence of modifications the overall fold of the tRNA is essentially the same as that of mature tRNA. However, there are a number of significant structural differences, such as rearrangements in a triplet base pair and a widened angle between the acceptor and anticodon stems. Contrary to previous observations, the anticodon adopts the same conformation as seen in mature tRNA.
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Affiliation(s)
- Robert T Byrne
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, North Yorkshire, YO10 5YW, UK
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43
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Structures of the tRNA export factor in the nuclear and cytosolic states. Nature 2009; 461:60-5. [PMID: 19680239 DOI: 10.1038/nature08394] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 08/06/2009] [Indexed: 11/08/2022]
Abstract
Transfer RNAs are among the most ubiquitous molecules in cells, central to decoding information from messenger RNAs on translating ribosomes. In eukaryotic cells, tRNAs are actively transported from their site of synthesis in the nucleus to their site of function in the cytosol. This is mediated by a dedicated nucleo-cytoplasmic transport factor of the karyopherin-beta family (Xpot, also known as Los1 in Saccharomyces cerevisiae). Here we report the 3.2 A resolution structure of Schizosaccharomyces pombe Xpot in complex with tRNA and RanGTP, and the 3.1 A structure of unbound Xpot, revealing both nuclear and cytosolic snapshots of this transport factor. Xpot undergoes a large conformational change on binding cargo, wrapping around the tRNA and, in particular, binding to the tRNA 5' and 3' ends. The binding mode explains how Xpot can recognize all mature tRNAs in the cell and yet distinguish them from those that have not been properly processed, thus coupling tRNA export to quality control.
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44
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tRNA recognition, processing, and disease: hypotheses around an unorthodox type of RNase P in human mitochondria. Mitochondrion 2009; 9:284-8. [PMID: 19376274 DOI: 10.1016/j.mito.2009.03.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Accepted: 03/24/2009] [Indexed: 11/24/2022]
Abstract
RNase P is the endonuclease responsible for the maturation of the 5' ends of tRNAs. A catalytic RNA component was long considered the premier attribute of the enzyme family. Ignoring this heritage, human mitochondria make their RNase P of three proteins only. While one of them appears to be the metallonuclease actually responsible for phosphodiester hydrolysis, the other two have been recruited from unrelated biochemical pathways and may be critical for substrate recognition. One of them is moreover identical to a previously identified amyloid-beta-binding protein, whereby it could link tRNA processing to mitochondrial dysfunction in Alzheimer's disease.
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45
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Crystallographic studies of DNA and RNA. Methods 2009; 47:168-76. [DOI: 10.1016/j.ymeth.2008.09.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 09/10/2008] [Indexed: 11/23/2022] Open
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47
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Takemoto C, Spremulli LL, Benkowski LA, Ueda T, Yokogawa T, Watanabe K. Unconventional decoding of the AUA codon as methionine by mitochondrial tRNAMet with the anticodon f5CAU as revealed with a mitochondrial in vitro translation system. Nucleic Acids Res 2009; 37:1616-27. [PMID: 19151083 PMCID: PMC2655697 DOI: 10.1093/nar/gkp001] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mitochondrial (mt) tRNAMet has the unusual modified nucleotide 5-formylcytidine (f5C) in the first position of the anticodon. This tRNA must translate both AUG and AUA as methionine. By constructing an in vitro translation system from bovine liver mitochondria, we examined the decoding properties of the native mt tRNAMet carrying f5C in the anticodon compared to a transcript that lacks the modification. The native mt Met-tRNA could recognize both AUA and AUG codons as Met, but the corresponding synthetic tRNAMet lacking f5C (anticodon CAU), recognized only the AUG codon in both the codon-dependent ribosomal binding and in vitro translation assays. Furthermore, the Escherichia coli elongator tRNAMetm with the anticodon ac4CAU (ac4C = 4-acetylcytidine) and the bovine cytoplasmic initiator tRNAMet (anticodon CAU) translated only the AUG codon for Met on mt ribosome. The codon recognition patterns of these tRNAs were the same on E. coli ribosomes. These results demonstrate that the f5C modification in mt tRNAMet plays a crucial role in decoding the nonuniversal AUA codon as Met, and that the genetic code variation is compensated by a change in the tRNA anticodon, not by a change in the ribosome. Base pairing models of f5C-G and f5C-A based on the chemical properties of f5C are presented.
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Affiliation(s)
- Chie Takemoto
- Department of Chemistry and Biotechnology, Graduate School of Engineering, University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
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48
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Recognition of aminoacyl-tRNA: a common molecular mechanism revealed by cryo-EM. EMBO J 2008; 27:3322-31. [PMID: 19020518 PMCID: PMC2586802 DOI: 10.1038/emboj.2008.243] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2008] [Accepted: 10/22/2008] [Indexed: 12/03/2022] Open
Abstract
The accuracy of ribosomal translation is achieved by an initial selection and a proofreading step, mediated by EF-Tu, which forms a ternary complex with aminoacyl(aa)-tRNA. To study the binding modes of different aa-tRNAs, we compared cryo-EM maps of the kirromycin-stalled ribosome bound with ternary complexes containing Phe-tRNAPhe, Trp-tRNATrp, or Leu-tRNALeuI. The three maps suggest a common binding manner of cognate aa-tRNAs in their specific binding with both the ribosome and EF-Tu. All three aa-tRNAs have the same ‘loaded spring' conformation with a kink and twist between the D-stem and anticodon stem. The three complexes are similarly integrated in an interaction network, extending from the anticodon loop through h44 and protein S12 to the EF-Tu-binding CCA end of aa-tRNA, proposed to signal cognate codon–anticodon interaction to the GTPase centre and tune the accuracy of aa-tRNA selection.
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49
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Shcherbakova I, Mitra S, Laederach A, Brenowitz M. Energy barriers, pathways, and dynamics during folding of large, multidomain RNAs. Curr Opin Chem Biol 2008; 12:655-66. [PMID: 18926923 DOI: 10.1016/j.cbpa.2008.09.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/22/2008] [Accepted: 09/16/2008] [Indexed: 10/21/2022]
Abstract
Large, multidomain RNA molecules are generally thought to fold following multiple pathways down rugged landscapes populated with intermediates and traps. A challenge to understanding RNA folding reactions is the complex relationships that exist between the structure of the RNA and its folding landscape. The identification of intermediate species that populate folding landscapes and characterization of elements of their structures are the key components to solving the RNA folding problem. This review explores recent studies that characterize the dominant pathways by which RNA folds, structural and dynamic features of intermediates that populate the folding landscape, and the energy barriers that separate the distinct steps of the folding process.
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Affiliation(s)
- Inna Shcherbakova
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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50
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Jones CN, Jones CI, Graham WD, Agris PF, Spremulli LL. A disease-causing point mutation in human mitochondrial tRNAMet rsults in tRNA misfolding leading to defects in translational initiation and elongation. J Biol Chem 2008; 283:34445-56. [PMID: 18835817 DOI: 10.1074/jbc.m806992200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial tRNA genes are hot spots for mutations that lead to human disease. A single point mutation (T4409C) in the gene for human mitochondrial tRNA(Met) (hmtRNA(Met)) has been found to cause mitochondrial myopathy. This mutation results in the replacement of U8 in hmtRNA(Met) with a C8. The hmtRNA(Met) serves both in translational initiation and elongation in human mitochondria making this tRNA of particular interest in mitochondrial protein synthesis. Here we show that the single 8U-->C mutation leads to a failure of the tRNA to respond conformationally to Mg(2+). This mutation results in a drastic disruption of the structure of the hmtRNA(Met), which significantly reduces its aminoacylation. The small fraction of hmtRNA(Met) that can be aminoacylated is not formylated by the mitochondrial Met-tRNA transformylase preventing its function in initiation, and it is unable to form a stable ternary complex with elongation factor EF-Tu preventing any participation in chain elongation. We have used structural probing and molecular reconstitution experiments to examine the structures formed by the normal and mutated tRNAs. In the presence of Mg(2+), the normal tRNA displays the structural features expected of a tRNA. However, even in the presence of Mg(2+), the mutated tRNA does not form the cloverleaf structure typical of tRNAs. Thus, we believe that this mutation has disrupted a critical Mg(2+)-binding site on the tRNA required for formation of the biologically active structure. This work establishes a foundation for understanding the physiological consequences of the numerous mitochondrial tRNA mutations that result in disease in humans.
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Affiliation(s)
- Christie N Jones
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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