1
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Strassler SE, Bowles IE, Krishnamohan A, Kim H, Edgington CB, Kuiper EG, Hancock CJ, Comstock LR, Jackman JE, Conn GL. tRNA m 1G9 modification depends on substrate-specific RNA conformational changes induced by the methyltransferase Trm10. J Biol Chem 2023; 299:105443. [PMID: 37949221 PMCID: PMC10704376 DOI: 10.1016/j.jbc.2023.105443] [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: 02/01/2023] [Revised: 10/19/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023] Open
Abstract
The methyltransferase Trm10 modifies a subset of tRNAs on the base N1 position of the ninth nucleotide in the tRNA core. Trm10 is conserved throughout Eukarya and Archaea, and mutations in the human gene (TRMT10A) have been linked to neurological disorders such as microcephaly and intellectual disability, as well as defects in glucose metabolism. Of the 26 tRNAs in yeast with guanosine at position 9, only 13 are substrates for Trm10. However, no common sequence or other posttranscriptional modifications have been identified among these substrates, suggesting the presence of some other tRNA feature(s) that allow Trm10 to distinguish substrate from nonsubstrate tRNAs. Here, we show that substrate recognition by Saccharomyces cerevisiae Trm10 is dependent on both intrinsic tRNA flexibility and the ability of the enzyme to induce specific tRNA conformational changes upon binding. Using the sensitive RNA structure-probing method SHAPE, conformational changes upon binding to Trm10 in tRNA substrates, but not nonsubstrates, were identified and mapped onto a model of Trm10-bound tRNA. These changes may play an important role in substrate recognition by allowing Trm10 to gain access to the target nucleotide. Our results highlight a novel mechanism of substrate recognition by a conserved tRNA modifying enzyme. Further, these studies reveal a strategy for substrate recognition that may be broadly employed by tRNA-modifying enzymes which must distinguish between structurally similar tRNA species.
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Affiliation(s)
- Sarah E Strassler
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
| | - Isobel E Bowles
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
| | - Aiswarya Krishnamohan
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
| | - Hyejeong Kim
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Catherine B Edgington
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Emily G Kuiper
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
| | - Clio J Hancock
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Lindsay R Comstock
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Jane E Jackman
- Department of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA; Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA.
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA.
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2
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Strassler SE, Bowles IE, Krishnamohan A, Kim H, Edgington CB, Kuiper EG, Hancock CJ, Comstock LR, Jackman JE, Conn GL. tRNA m 1G9 modification depends on substrate-specific RNA conformational changes induced by the methyltransferase Trm10. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.01.526536. [PMID: 36778341 PMCID: PMC9915607 DOI: 10.1101/2023.02.01.526536] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The methyltransferase Trm10 modifies a subset of tRNAs on the base N1 position of the 9th nucleotide in the tRNA core. Trm10 is conserved throughout Eukarya and Archaea, and mutations in the human gene (TRMT10A) have been linked to neurological disorders such as microcephaly and intellectual disability, as well as defects in glucose metabolism. Of the 26 tRNAs in yeast with guanosine at position 9, only 14 are substrates for Trm10. However, no common sequence or other posttranscriptional modifications have been identified among these substrates, suggesting the presence of some other tRNA feature(s) which allow Trm10 to distinguish substrate from nonsubstrate tRNAs. Here, we show that substrate recognition by Saccharomyces cerevisiae Trm10 is dependent on both intrinsic tRNA flexibility and the ability of the enzyme to induce specific tRNA conformational changes upon binding. Using the sensitive RNA structure-probing method SHAPE, conformational changes upon binding to Trm10 in tRNA substrates, but not nonsubstrates, were identified and mapped onto a model of Trm10-bound tRNA. These changes may play an important role in substrate recognition by allowing Trm10 to gain access to the target nucleotide. Our results highlight a novel mechanism of substrate recognition by a conserved tRNA modifying enzyme. Further, these studies reveal a strategy for substrate recognition that may be broadly employed by tRNA-modifying enzymes which must distinguish between structurally similar tRNA species.
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Affiliation(s)
- Sarah E. Strassler
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta GA, 30322, USA
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University
| | - Isobel E. Bowles
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, 484 W. 12 Avenue, Columbus, OH, 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, 484 W. 12 Avenue, Columbus, OH, 43210, USA
| | - Aiswarya Krishnamohan
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, 484 W. 12 Avenue, Columbus, OH, 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, 484 W. 12 Avenue, Columbus, OH, 43210, USA
| | - Hyejeong Kim
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, 484 W. 12 Avenue, Columbus, OH, 43210, USA
| | - Catherine B. Edgington
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, 484 W. 12 Avenue, Columbus, OH, 43210, USA
| | - Emily G. Kuiper
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta GA, 30322, USA
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University
| | - Clio J. Hancock
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta GA, 30322, USA
| | - Lindsay R. Comstock
- Department of Chemistry, Wake Forest University, 1834 Wake Forest Road, Winston-Salem, NC 27106, USA
| | - Jane E. Jackman
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, 484 W. 12 Avenue, Columbus, OH, 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, 484 W. 12 Avenue, Columbus, OH, 43210, USA
| | - Graeme L. Conn
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road NE, Atlanta GA, 30322, USA
- Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University
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3
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Abstract
Although fragment-based drug discovery (FBDD) has been successfully implemented and well-explored for protein targets, its feasibility for RNA targets is emerging. Despite the challenges associated with the selective targeting of RNA, efforts to integrate known methods of RNA binder discovery with fragment-based approaches have been fruitful, as a few bioactive ligands have been identified. Here, we review various fragment-based approaches implemented for RNA targets and provide insights into experimental design and outcomes to guide future work in the area. Indeed, investigations surrounding the molecular recognition of RNA by fragments address rather important questions such as the limits of molecular weight that confer selective binding and the physicochemical properties favorable for RNA binding and bioactivity.
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Affiliation(s)
- Blessy M. Suresh
- UF Scripps Biomedical Research & The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Amirhossein Taghavi
- UF Scripps Biomedical Research & The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Jessica L. Childs-Disney
- UF Scripps Biomedical Research & The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - Matthew D. Disney
- UF Scripps Biomedical Research & The Scripps Research Institute, Department of Chemistry, 130 Scripps Way, Jupiter, Florida 33458, United States
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4
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Strassler SE, Bowles IE, Dey D, Jackman JE, Conn GL. Tied up in knots: Untangling substrate recognition by the SPOUT methyltransferases. J Biol Chem 2022; 298:102393. [PMID: 35988649 PMCID: PMC9508554 DOI: 10.1016/j.jbc.2022.102393] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 08/10/2022] [Accepted: 08/11/2022] [Indexed: 10/25/2022] Open
Abstract
The SpoU-TrmD (SPOUT) methyltransferase superfamily was designated when structural similarity was identified between the transfer RNA-modifying enzymes TrmH (SpoU) and TrmD. SPOUT methyltransferases are found in all domains of life and predominantly modify transfer RNA or ribosomal RNA substrates, though one instance of an enzyme with a protein substrate has been reported. Modifications placed by SPOUT methyltransferases play diverse roles in regulating cellular processes such as ensuring translational fidelity, altering RNA stability, and conferring bacterial resistance to antibiotics. This large collection of S-adenosyl-L-methionine-dependent methyltransferases is defined by a unique α/β fold with a deep trefoil knot in their catalytic (SPOUT) domain. Herein, we describe current knowledge of SPOUT enzyme structure, domain architecture, and key elements of catalytic function, including S-adenosyl-L-methionine co-substrate binding, beginning with a new sequence alignment that divides the SPOUT methyltransferase superfamily into four major clades. Finally, a major focus of this review will be on our growing understanding of how these diverse enzymes accomplish the molecular feat of specific substrate recognition and modification, as highlighted by recent advances in our knowledge of protein-RNA complex structures and the discovery of the dependence of one SPOUT methyltransferase on metal ion binding for catalysis. Considering the broad biological roles of RNA modifications, developing a deeper understanding of the process of substrate recognition by the SPOUT enzymes will be critical for defining many facets of fundamental RNA biology with implications for human disease.
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Affiliation(s)
- Sarah E Strassler
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA
| | - Isobel E Bowles
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, Columbus, Ohio, USA
| | - Debayan Dey
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jane E Jackman
- Department of Chemistry and Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, Columbus, Ohio, USA.
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell and Developmental Biology, Graduate Division of Biological and Biomedical Sciences, Emory University, Atlanta, Georgia, USA.
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5
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Ongpipattanakul C, Desormeaux EK, DiCaprio A, van der Donk WA, Mitchell DA, Nair SK. Mechanism of Action of Ribosomally Synthesized and Post-Translationally Modified Peptides. Chem Rev 2022; 122:14722-14814. [PMID: 36049139 PMCID: PMC9897510 DOI: 10.1021/acs.chemrev.2c00210] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a natural product class that has undergone significant expansion due to the rapid growth in genome sequencing data and recognition that they are made by biosynthetic pathways that share many characteristic features. Their mode of actions cover a wide range of biological processes and include binding to membranes, receptors, enzymes, lipids, RNA, and metals as well as use as cofactors and signaling molecules. This review covers the currently known modes of action (MOA) of RiPPs. In turn, the mechanisms by which these molecules interact with their natural targets provide a rich set of molecular paradigms that can be used for the design or evolution of new or improved activities given the relative ease of engineering RiPPs. In this review, coverage is limited to RiPPs originating from bacteria.
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Affiliation(s)
- Chayanid Ongpipattanakul
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Emily K. Desormeaux
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Adam DiCaprio
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
| | - Wilfred A. van der Donk
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
| | - Douglas A. Mitchell
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
- Departments of Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, Illinois 61801, USA
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6
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Wang A, Levi M, Mohanty U, Whitford PC. Diffuse Ions Coordinate Dynamics in a Ribonucleoprotein Assembly. J Am Chem Soc 2022; 144:9510-9522. [PMID: 35593477 DOI: 10.1021/jacs.2c04082] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Proper ionic concentrations are required for the functional dynamics of RNA and ribonucleoprotein (RNP) assemblies. While experimental and computational techniques have provided many insights into the properties of chelated ions, less is known about the energetic contributions of diffuse ions to large-scale conformational rearrangements. To address this, we present a model that is designed to quantify the influence of diffuse monovalent and divalent ions on the dynamics of biomolecular assemblies. This model employs all-atom (non-H) resolution and explicit ions, where effective potentials account for hydration effects. We first show that the model accurately predicts the number of excess Mg2+ ions for prototypical RNA systems, at a level comparable to modern coarse-grained models. We then apply the model to a complete ribosome and show how the balance between diffuse Mg2+ and K+ ions can control the dynamics of tRNA molecules during translation. The model predicts differential effects of diffuse ions on the free-energy barrier associated with tRNA entry and the energy of tRNA binding to the ribosome. Together, this analysis reveals the direct impact of diffuse ions on the dynamics of an RNP assembly.
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Affiliation(s)
- Ailun Wang
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States.,Center for Theoretical Biological Physics, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Mariana Levi
- Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Udayan Mohanty
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, United States
| | - Paul C Whitford
- Center for Theoretical Biological Physics, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.,Department of Physics, Northeastern University, Dana Research Center 111, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
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7
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Wei J, Chen S, Zong L, Gao X, Li Y. Protein-RNA interaction prediction with deep learning: structure matters. Brief Bioinform 2022; 23:bbab540. [PMID: 34929730 PMCID: PMC8790951 DOI: 10.1093/bib/bbab540] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/14/2021] [Accepted: 11/22/2021] [Indexed: 12/11/2022] Open
Abstract
Protein-RNA interactions are of vital importance to a variety of cellular activities. Both experimental and computational techniques have been developed to study the interactions. Because of the limitation of the previous database, especially the lack of protein structure data, most of the existing computational methods rely heavily on the sequence data, with only a small portion of the methods utilizing the structural information. Recently, AlphaFold has revolutionized the entire protein and biology field. Foreseeably, the protein-RNA interaction prediction will also be promoted significantly in the upcoming years. In this work, we give a thorough review of this field, surveying both the binding site and binding preference prediction problems and covering the commonly used datasets, features and models. We also point out the potential challenges and opportunities in this field. This survey summarizes the development of the RNA-binding protein-RNA interaction field in the past and foresees its future development in the post-AlphaFold era.
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Affiliation(s)
- Junkang Wei
- Department of Computer Science and Engineering (CSE), The Chinese
University of Hong Kong (CUHK), 999077, Hong Kong SAR, China
| | - Siyuan Chen
- Computational Bioscience Research Center (CBRC),
King Abdullah University of Science and Technology (KAUST),
23955-6900, Thuwal, Saudi Arabia
| | - Licheng Zong
- Department of Computer Science and Engineering (CSE), The Chinese
University of Hong Kong (CUHK), 999077, Hong Kong SAR, China
| | - Xin Gao
- Computational Bioscience Research Center (CBRC),
King Abdullah University of Science and Technology (KAUST),
23955-6900, Thuwal, Saudi Arabia
| | - Yu Li
- Department of Computer Science and Engineering (CSE), The Chinese
University of Hong Kong (CUHK), 999077, Hong Kong SAR, China
- The CUHK Shenzhen Research Institute, Hi-Tech Park, 518057,
Shenzhen, China
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8
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Trachman RJ, Ferré-D'Amaré AR. An uncommon [K +(Mg 2+) 2] metal ion triad imparts stability and selectivity to the Guanidine-I riboswitch. RNA (NEW YORK, N.Y.) 2021; 27:1257-1264. [PMID: 34257148 PMCID: PMC8457001 DOI: 10.1261/rna.078824.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/05/2021] [Indexed: 06/13/2023]
Abstract
The widespread ykkC-I riboswitch class exemplifies divergent riboswitch evolution. To analyze how natural selection has diversified its versatile RNA fold, we determined the X-ray crystal structure of the Burkholderia sp. TJI49 ykkC-I subtype-1 (Guanidine-I) riboswitch aptamer domain. Differing from the previously reported structures of orthologs from Dickeya dadantii and Sulfobacillus acidophilus, our Burkholderia structure reveals a chelated K+ ion adjacent to two Mg2+ ions in the guanidine-binding pocket. Thermal melting analysis shows that K+ chelation, which induces localized conformational changes in the binding pocket, improves guanidinium-RNA interactions. Analysis of ribosome structures suggests that the [K+(Mg2+)2] ion triad is uncommon. It is, however, reminiscent of metal ion clusters found in the active sites of ribozymes and DNA polymerases. Previous structural characterization of ykkC-I subtype-2 RNAs, which bind the effector ligands ppGpp and PRPP, indicate that in those paralogs, an adenine responsible for K+ chelation in the Burkholderia Guanidine-I riboswitch is replaced by a pyrimidine. This mutation results in a water molecule and Mg2+ ion binding in place of the K+ ion. Thus, our structural analysis demonstrates how ion and solvent chelation tune divergent ligand specificity and affinity among ykkC-I riboswitches.
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Affiliation(s)
- Robert J Trachman
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-8012, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-8012, USA
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9
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He W, Chen YL, Pollack L, Kirmizialtin S. The structural plasticity of nucleic acid duplexes revealed by WAXS and MD. SCIENCE ADVANCES 2021; 7:7/17/eabf6106. [PMID: 33893104 PMCID: PMC8064643 DOI: 10.1126/sciadv.abf6106] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 03/05/2021] [Indexed: 05/06/2023]
Abstract
Double-stranded DNA (dsDNA) and RNA (dsRNA) helices display an unusual structural diversity. Some structural variations are linked to sequence and may serve as signaling units for protein-binding partners. Therefore, elucidating the mechanisms and factors that modulate these variations is of fundamental importance. While the structural diversity of dsDNA has been extensively studied, similar studies have not been performed for dsRNA. Because of the increasing awareness of RNA's diverse biological roles, such studies are timely and increasingly important. We integrate solution x-ray scattering at wide angles (WAXS) with all-atom molecular dynamics simulations to explore the conformational ensemble of duplex topologies for different sequences and salt conditions. These tightly coordinated studies identify robust correlations between features in the WAXS profiles and duplex geometry and enable atomic-level insights into the structural diversity of DNA and RNA duplexes. Notably, dsRNA displays a marked sensitivity to the valence and identity of its associated cations.
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Affiliation(s)
- Weiwei He
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- Department of Chemistry, New York University, New York, NY, USA
| | - Yen-Lin Chen
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY, USA.
| | - Serdal Kirmizialtin
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates.
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10
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Choi KHA, Yang L, Lee KM, Yu CWH, Banfield DK, Ito K, Uchiumi T, Wong KB. Structural and Mutagenesis Studies Evince the Role of the Extended Protuberant Domain of Ribosomal Protein uL10 in Protein Translation. Biochemistry 2019; 58:3744-3754. [PMID: 31419120 DOI: 10.1021/acs.biochem.9b00528] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lateral stalk of ribosomes constitutes the GTPase-associated center and is responsible for recruiting translation factors to the ribosomes. The eukaryotic stalk contains a P-complex, in which one molecule of uL10 (formerly known as P0) protein binds two copies of P1/P2 heterodimers. Unlike bacterial uL10, eukaryotic uL10 has an extended protuberant (uL10ext) domain inserted into the N-terminal RNA-binding domain. Here, we determined the solution structure of the extended protuberant domain of Bombyx mori uL10 by nuclear magnetic resonance spectroscopy. Comparison of the structures of the B. mori uL10ext domain with eRF1-bound and eEF2-bound ribosomes revealed significant structural rearrangement in a "hinge" region surrounding Phe183, a residue conserved in eukaryotic but not in archaeal uL10. 15N relaxation analyses showed that residues in the hinge region have significantly large values of transverse relaxation rates. To test the role of the conserved phenylalanine residue, we created a yeast mutant strain expressing an F181A variant of uL10. An in vitro translation assay showed that the alanine substitution increased the level of polyphenylalanine synthesis by ∼33%. Taken together, our results suggest that the hinge motion of the uL10ext domain facilitates the binding of different translation factors to the GTPase-associated center during protein synthesis.
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Affiliation(s)
- Kwok-Ho Andrew Choi
- School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology , The Chinese University of Hong Kong , Shatin , Hong Kong, China
| | - Lei Yang
- School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology , The Chinese University of Hong Kong , Shatin , Hong Kong, China
| | - Ka-Ming Lee
- School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology , The Chinese University of Hong Kong , Shatin , Hong Kong, China
| | - Conny Wing-Heng Yu
- School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology , The Chinese University of Hong Kong , Shatin , Hong Kong, China
| | - David K Banfield
- Division of Life Science , Hong Kong University of Science and Technology , Clear Water Bay , Hong Kong , China
| | - Kosuke Ito
- Department of Biology, Faculty of Science , Niigata University , Ikarashi 2-8050 , Nishi-ku, Niigata 950-2191 , Japan
| | - Toshio Uchiumi
- Department of Biology, Faculty of Science , Niigata University , Ikarashi 2-8050 , Nishi-ku, Niigata 950-2191 , Japan
| | - Kam-Bo Wong
- School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology , The Chinese University of Hong Kong , Shatin , Hong Kong, China
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11
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Koirala D, Shao Y, Koldobskaya Y, Fuller JR, Watkins AM, Shelke SA, Pilipenko EV, Das R, Rice PA, Piccirilli JA. A conserved RNA structural motif for organizing topology within picornaviral internal ribosome entry sites. Nat Commun 2019; 10:3629. [PMID: 31399592 PMCID: PMC6689051 DOI: 10.1038/s41467-019-11585-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 07/09/2019] [Indexed: 12/30/2022] Open
Abstract
Picornaviral IRES elements are essential for initiating the cap-independent viral translation. However, three-dimensional structures of these elements remain elusive. Here, we report a 2.84-Å resolution crystal structure of hepatitis A virus IRES domain V (dV) in complex with a synthetic antibody fragment-a crystallization chaperone. The RNA adopts a three-way junction structure, topologically organized by an adenine-rich stem-loop motif. Despite no obvious sequence homology, the dV architecture shows a striking similarity to a circularly permuted form of encephalomyocarditis virus J-K domain, suggesting a conserved strategy for organizing the domain architecture. Recurrence of the motif led us to use homology modeling tools to compute a 3-dimensional structure of the corresponding domain of foot-and-mouth disease virus, revealing an analogous domain organizing motif. The topological conservation observed among these IRESs and other viral domains implicates a structured three-way junction as an architectural scaffold to pre-organize helical domains for recruiting the translation initiation machinery.
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Affiliation(s)
- Deepak Koirala
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Yaming Shao
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Yelena Koldobskaya
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - James R Fuller
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Andrew M Watkins
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Sandip A Shelke
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Evgeny V Pilipenko
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Rhiju Das
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Phoebe A Rice
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA
| | - Joseph A Piccirilli
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, 60637, USA.
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA.
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12
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Lammert H, Wang A, Mohanty U, Onuchic JN. RNA as a Complex Polymer with Coupled Dynamics of Ions and Water in the Outer Solvation Sphere. J Phys Chem B 2018; 122:11218-11227. [PMID: 30102033 DOI: 10.1021/acs.jpcb.8b06874] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We unravel the internal and collective modes of a widely studied 58-nucleotide rRNA fragment in solvent using atomically detailed molecular dynamics simulations. The variation of lifetimes for water hydrogen bonds with nucleotide groups indicates heterogeneity of water dynamics on the RNA surface. The time scales of interactions of the discrete water molecules with RNA nucleotides extend from several hundred picoseconds to a few nanoseconds. We determine all of the association sites and the spatial distribution of residence times for Mg2+, K+, and water molecules in those sites. We provide insights into the population of Mg2+ and K+ ions and water molecules in the outer sphere and how their fluctuations are intricately linked with the kinetics of the 58-mer. We find that many of the long-lived Mg2+ sites identified from the simulations agree with the locations of ions in the X-ray structure. We determine the excess ion atmosphere around the rRNA and compare it with experimental data. We investigate the collective behavior of RNA, ions, and water, by performing a joint principle component analysis for the Cartesian coordinates of the RNA phosphorus atoms and for the occupation counts of the association sites. Our results indicate that the 58-mer system is a complex polymer, composed of RNA that is encased by a fluctuating network of associated counterions, co-ions, and water.
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Affiliation(s)
| | - Ailun Wang
- Department of Chemistry , Boston College , Chestnut Hill , Massachusetts 02467 , United States
| | - Udayan Mohanty
- Department of Chemistry , Boston College , Chestnut Hill , Massachusetts 02467 , United States
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13
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Nichols PJ, Born A, Henen MA, Strotz D, Celestine CN, Güntert P, Vögeli B. Extending the Applicability of Exact Nuclear Overhauser Enhancements to Large Proteins and RNA. Chembiochem 2018; 19:1695-1701. [PMID: 29883016 DOI: 10.1002/cbic.201800237] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Indexed: 01/24/2023]
Abstract
Distance-dependent nuclear Overhauser enhancements (NOEs) are one of the most popular and important experimental restraints for calculating NMR structures. Despite this, they are mostly employed as semiquantitative upper distance bounds, and this discards the wealth of information that is encoded in the cross-relaxation rate constant. Information that is lost includes exact distances between protons and dynamics that occur on the sub-millisecond timescale. Our recently introduced exact measurement of the NOE (eNOE) requires little additional experimental effort relative to other NMR observables. So far, we have used eNOEs to calculate multistate ensembles of proteins up to approximately 150 residues. Here, we briefly revisit eNOE methodology and present two new directions for the use of eNOEs: applications to large proteins and RNA.
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Affiliation(s)
- Parker J Nichols
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO, 80045, USA
| | - Alexandra Born
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO, 80045, USA
| | - Morkos A Henen
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO, 80045, USA
- Faculty of Pharmacy, Mansoura University, Mansoura, 35516, Egypt
| | - Dean Strotz
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
| | - Chi N Celestine
- Department of Medical Biochemistry and Microbiology, Uppsala University, BMC Box 582, 75123, Uppsala, Sweden
| | - Peter Güntert
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zürich, Switzerland
- Institute of Biophysical Chemistry, Goethe Universität Frankfurt, Max-von-Laue-Strasse 9, 60438, Frankfurt am Main, Germany
- Graduate School of Science, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachioji, Tokyo, 192-0397, Japan
| | - Beat Vögeli
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Anschutz Medical Campus, 12801 East 17th Avenue, Aurora, CO, 80045, USA
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14
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Carr CE, Marky LA. Effect of GCAA stabilizing loops on three- and four-way intramolecular junctions. Phys Chem Chem Phys 2018; 20:5046-5056. [PMID: 29388988 DOI: 10.1039/c7cp08329g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Tetraloops are a common way of changing the melting behavior of a DNA or RNA structure without changing the sequence of the stem. Because of the ubiquitous nature of tetraloops, our goal is to understand the effect a GCAA tetraloop, which belongs to the GNRA family of tetraloops, has on the unfolding thermodynamics of intramolecular junctions. Specifically, we have described the melting behavior of intramolecular three-way and four-way junctions where a T5 loop has been replaced with a GCAA tetraloops in different positions. Their thermodynamic profiles, including ΔnNa+ and ΔnW, were analyzed based on the position of the tetraloop. We obtained between -16.7 and -27.5 kcal mol-1 for all junctions studied. The experimental data indicates the influence of the GCAA tetraloop is primarily dictated by the native unfolding of the junction; if the tetraloop is placed on a stem that unfolds as a single domain when the tetraloop is not present, it will unfold as a single domain when the tetraloop is present but with a higher thermal stability. Conversely, if the tetraloop is placed on a stem which unfolds cooperatively with other stems when the tetraloop is not present, the tetraloop will increase the thermal stability of all the stems in the melting domain. The oligonucleotide structure and not the tetraloop itself affects ion uptake; three-way junctions do not gain an increase in ion uptake, but four-way junctions do. This is not the case for water immobilization, where the position of the tetraloop dictates the amount of water immobilized.
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Affiliation(s)
- Carolyn E Carr
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, 986025 Nebraska Medical Center, Omaha, NE 68198-6025, USA.
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15
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Nikulin AD. Structural Aspects of Ribosomal RNA Recognition by Ribosomal Proteins. BIOCHEMISTRY (MOSCOW) 2018; 83:S111-S133. [DOI: 10.1134/s0006297918140109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Jamiolkowski RM, Chen C, Cooperman BS, Goldman YE. tRNA Fluctuations Observed on Stalled Ribosomes Are Suppressed during Ongoing Protein Synthesis. Biophys J 2018; 113:2326-2335. [PMID: 29211986 DOI: 10.1016/j.bpj.2017.08.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/25/2017] [Accepted: 08/30/2017] [Indexed: 01/13/2023] Open
Abstract
The pretranslocation complex of the ribosome can undergo spontaneous fluctuations of messenger RNA and transfer RNAs (tRNAs) between classical and hybrid states, and occupation of the hybrid tRNA positions has been proposed to precede translocation. The classical and hybrid state tRNA positions have been extensively characterized when the ribosome is stalled along the messenger RNA by either the absence or delayed addition of elongation factor G (EF-G), or by the presence of antibiotics or GTP analogs that block translocation. However, during multiple ongoing elongation cycles when both EF-G and ternary complexes are present, EF-G can bind to the pretranslocation complex much faster than the timescale of the classic-hybrid transitions. Using single-molecule fluorescence resonance energy transfer between adjacent tRNAs and between A-site tRNA and ribosomal protein L11, we found that the tRNAs do not fluctuate between the hybrid and classical states, but instead adopt a position with fluorescence resonance energy transfer efficiencies between those of the stalled classical and hybrid states.
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Affiliation(s)
- Ryan M Jamiolkowski
- Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chunlai Chen
- Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; School of Life Sciences, Tsinghua-Peking Joint Center for Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Tsinghua University, Beijing, China.
| | - Barry S Cooperman
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania.
| | - Yale E Goldman
- Pennsylvania Muscle Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania.
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17
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Grechishnikova DA, Poptsova MS. The Physical and Geometric Properties of Human Transposon Stem–Loop Structures under Natural Selection. Biophysics (Nagoya-shi) 2017. [DOI: 10.1134/s0006350917060070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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18
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Carr CE, Marky LA. Investigation of the Melting Behavior of DNA Three-Way Junctions in the Closed and Open States. Biophys J 2017; 113:529-539. [PMID: 28793208 DOI: 10.1016/j.bpj.2017.06.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/09/2017] [Accepted: 06/14/2017] [Indexed: 10/19/2022] Open
Abstract
Intramolecular three-way junctions are commonly found in both DNA and RNA. These structures are functionally relevant in ribozymes, riboswitches, rRNA, and during replication. In this work, we present a thermodynamic description of the unfolding of DNA intramolecular three-way junctions. We used a combination of spectroscopic and calorimetric techniques to investigate the folding/unfolding thermodynamics of two three-way junctions with a closed (Closed-J) or open (Open-J) junction and their appropriate control stem-loop motifs (GAAATT-Hp, CTATC-Hp, and Dumbbell). The overall results show that both junctions are stable over a wide range of salt concentrations. However, Open-J is more stable due to a higher enthalpy contribution from the formation of a higher number of basepair stacks whereas Closed-J has a defined structure and retains the basepair stacking of all three stems. The comparison of the experimental results of Closed-J and Open-J with those of their component stem-loop motifs allowed us to be more specific about their cooperative unfolding. For instance, Closed-J sacrifices thermal stability of the Dumbbell structure to maintain an overall folded state. At higher salt concentration, the simultaneous unfolding of the above domains is lost, resulting in the unfolding of the three separate stems. In contrast, the junction of Open-J in low salt retains the thermal and enthalpic stability of the Dumbbell structure although sacrificing stability of the CTATC stem. The relative stability of Dumbbell is the primary reason for the higher ΔG°(5), or free energy, value seen for Open-J at low salt. Higher salt not only maintains thermal stability of the Dumbbell structure in Open-J but causes the CTATC stem to fully fold.
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Affiliation(s)
- Carolyn E Carr
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska
| | - Luis A Marky
- Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Nebraska Medical Center, Omaha, Nebraska.
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19
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Hayatshahi HS, Bergonzo C, Cheatham III TE. Investigating the ion dependence of the first unfolding step of GTPase-Associating Center ribosomal RNA. J Biomol Struct Dyn 2017; 36:243-253. [DOI: 10.1080/07391102.2016.1274272] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Hamed S. Hayatshahi
- Department of Medicinal Chemistry, College of Pharmacy, The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, USA
| | - Christina Bergonzo
- Department of Medicinal Chemistry, College of Pharmacy, The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, USA
| | - Thomas E. Cheatham III
- Department of Medicinal Chemistry, College of Pharmacy, The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, USA
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20
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Hayatshahi H, Roe DR, Galindo-Murillo R, Hall KB, Cheatham TE. Computational Assessment of Potassium and Magnesium Ion Binding to a Buried Pocket in GTPase-Associating Center RNA. J Phys Chem B 2017; 121:451-462. [PMID: 27983843 PMCID: PMC5278497 DOI: 10.1021/acs.jpcb.6b08764] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/15/2016] [Indexed: 01/24/2023]
Abstract
An experimentally well-studied model of RNA tertiary structures is a 58mer rRNA fragment, known as GTPase-associating center (GAC) RNA, in which a highly negative pocket walled by phosphate oxygen atoms is stabilized by a chelated cation. Although such deep pockets with more than one direct phosphate to ion chelation site normally include magnesium, as shown in one GAC crystal structure, another GAC crystal structure and solution experiments suggest potassium at this site. Both crystal structures also depict two magnesium ions directly bound to the phosphate groups comprising this controversial pocket. Here, we used classical molecular dynamics simulations as well as umbrella sampling to investigate the possibility of binding of potassium versus magnesium inside the pocket and to better characterize the chelation of one of the binding magnesium ions outside the pocket. The results support the preference of the pocket to accommodate potassium rather than magnesium and suggest that one of the closely binding magnesium ions can only bind at high magnesium concentrations, such as might be present during crystallization. This work illustrates the complementary utility of molecular modeling approaches with atomic-level detail in resolving discrepancies between conflicting experimental results.
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Affiliation(s)
- Hamed
S. Hayatshahi
- Department
of Medicinal Chemistry, College of Pharmacy,
The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, United States
| | - Daniel R. Roe
- Department
of Medicinal Chemistry, College of Pharmacy,
The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, United States
| | - Rodrigo Galindo-Murillo
- Department
of Medicinal Chemistry, College of Pharmacy,
The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, United States
| | - Kathleen B. Hall
- Department
of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Thomas E. Cheatham
- Department
of Medicinal Chemistry, College of Pharmacy,
The University of Utah, 2000 East 30 South Skaggs 307, Salt Lake City, Utah 84112-5820, United States
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21
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Abstract
Single-stranded RNA molecules fold into extraordinarily complicated secondary and tertiary structures as a result of intramolecular base pairing. In vivo, these RNA structures are not static. Instead, they are remodeled in response to changes in the prevailing physicochemical environment of the cell and as a result of intermolecular base pairing and interactions with RNA-binding proteins. Remarkable technical advances now allow us to probe RNA secondary structure at single-nucleotide resolution and genome-wide, both in vitro and in vivo. These data sets provide new glimpses into the RNA universe. Analyses of RNA structuromes in HIV, yeast, Arabidopsis, and mammalian cells and tissues have revealed regulatory effects of RNA structure on messenger RNA (mRNA) polyadenylation, splicing, translation, and turnover. Application of new methods for genome-wide identification of mRNA modifications, particularly methylation and pseudouridylation, has shown that the RNA "epitranscriptome" both influences and is influenced by RNA structure. In this review, we describe newly developed genome-wide RNA structure-probing methods and synthesize the information emerging from their application.
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Affiliation(s)
- Philip C Bevilacqua
- Department of Chemistry.,Department of Biochemistry and Molecular Biology.,Center for RNA Molecular Biology
| | | | - Zhao Su
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802;
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, Pennsylvania 16802;
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22
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Lanier KA, Athavale SS, Petrov AS, Wartell R, Williams LD. Imprint of Ancient Evolution on rRNA Folding. Biochemistry 2016; 55:4603-13. [DOI: 10.1021/acs.biochem.6b00168] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kathryn A. Lanier
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Shreyas S. Athavale
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Anton S. Petrov
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Roger Wartell
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Loren Dean Williams
- School of Chemistry and Biochemistry and ‡School of Biology, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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23
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Bertucat G, Lavery R, Prévost C. A Mechanism for RecA-Promoted Sequence Homology Recognition and Strand Exchange Between Single-Stranded DNA and Duplex DNA, via Triple-Helical Intermediates. J Biomol Struct Dyn 2016; 17 Suppl 1:147-53. [PMID: 22607418 DOI: 10.1080/07391102.2000.10506615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Abstract A central function of RecA protein during homologous recombination is to promote sequence recognition and strand exchange between a stretched and unwound single-stranded DNA, to which it is complexed, and a duplex DNA. By studying the properties of DNA under the conditions of deformation imposed by RecA, we propose a model for recognition and strand exchange at the atomic level, via unusual triple-helical intermediates. In this model, association takes place within a stretched and unwound triple helix of a new type, where the invading single strand occupies the minor groove of the duplex in a parallel orientation. Our calculations indicate that strand exchange within this structure is exothermic and results in a triple helix where the third strand interacts in the major groove, the so-called R-DNA triple helix. Preliminary calculations suggest that sequence homology recognition within the triplex of association is partial and that it is completed during strand exchange and product formation.
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Affiliation(s)
- G Bertucat
- a Laboratoire de Biochimie Théorique, CNRS UPR 9080 , Institut de Biologie Physico-Chimique , 13, rue Pierre et Marie Curie , 75005 , Paris , France
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24
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Abstract
Metal ions are essential cofactors for the structure and functions of nucleic acids. Yet, the early discovery in the 70s of the crucial role of Mg(2+) in stabilizing tRNA structures has occulted for a long time the importance of monovalent cations. Renewed interest in these ions was brought in the late 90s by the discovery of specific potassium metal ions in the core of a group I intron. Their importance in nucleic acid folding and catalytic activity is now well established. However, detection of K(+) and Na(+) ions is notoriously problematic and the question about their specificity is recurrent. Here we review the different methods that can be used to detect K(+) and Na(+) ions in nucleic acid structures such as X-ray crystallography, nuclear magnetic resonance or molecular dynamics simulations. We also discuss specific versus non-specific binding to different structures through various examples.
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Affiliation(s)
- Pascal Auffinger
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC, CNRS, 15 rue René Descartes, F-67084, Strasbourg, France.
| | - Luigi D'Ascenzo
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC, CNRS, 15 rue René Descartes, F-67084, Strasbourg, France.
| | - Eric Ennifar
- Architecture et Réactivité de l'ARN, Université de Strasbourg, IBMC, CNRS, 15 rue René Descartes, F-67084, Strasbourg, France.
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25
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Schudoma C. It's a loop world - single strands in RNA as structural and functional elements. Biomol Concepts 2015; 2:171-81. [PMID: 25962027 DOI: 10.1515/bmc.2011.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 03/25/2011] [Indexed: 01/31/2023] Open
Abstract
Unpaired regions in RNA molecules - loops - are centrally involved in defining the characteristic three-dimensional (3D) architecture of RNAs and are of high interest in RNA engineering and design. Loops adopt diverse, but specific conformations stabilised by complex tertiary structural interactions that provide structural flexibility to RNA structures that would otherwise not be possible if they only consisted of the rigid A-helical shapes usually formed by canonical base pairing. By participating in sequence-non-local contacts, they furthermore contribute to stabilising the overall fold of RNA molecules. Interactions between RNAs and other nucleic acids, proteins, or small molecules are also generally mediated by RNA loop structures. Therefore, the function of an RNA molecule is generally dependent on its loops. Examples include intermolecular interactions between RNAs as part of the microRNA processing pathways, ribozymatic activity, or riboswitch-ligand interactions. Bioinformatics approaches have been successfully applied to the identification of novel RNA structural motifs including loops, local and global RNA 3D structure prediction, and structural and conformational analysis of RNAs and have contributed to a better understanding of the sequence-structure-function relationships in RNA loops.
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26
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Mitroshin I, Garber M, Gabdulkhakov A. Crystallographic analysis of archaeal ribosomal protein L11. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2015; 71:1083-7. [PMID: 26249704 DOI: 10.1107/s2053230x15011395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 06/12/2015] [Indexed: 11/10/2022]
Abstract
Ribosomal protein L11 is an important part of the GTPase-associated centre in ribosomes of all organisms. L11 is a highly conserved two-domain ribosomal protein. The C-terminal domain of L11 is an RNA-binding domain that binds to a fragment of 23S rRNA and stabilizes its structure. The complex between L11 and 23S rRNA is involved in the GTPase activity of the translation elongation and release factors. Bacterial and archaeal L11-rRNA complexes are targets for peptide antibiotics of the thiazole class. To date, there is no complete structure of archaeal L11 owing to the mobility of the N-terminal domain of the protein. Here, the crystallization and X-ray analysis of the ribosomal protein L11 from Methanococcus jannaschii are reported. Crystals of the native protein and its selenomethionine derivative belonged to the orthorhombic space group I222 and were suitable for structural studies. Native and single-wavelength anomalous dispersion data sets have been collected and determination of the structure is in progress.
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Affiliation(s)
- Ivan Mitroshin
- Laboratory for Structural Studies of the Translation Apparatus, Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russian Federation
| | - Maria Garber
- Laboratory for Structural Studies of the Translation Apparatus, Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russian Federation
| | - Azat Gabdulkhakov
- Laboratory for Structural Studies of the Translation Apparatus, Institute of Protein Research, Russian Academy of Sciences, Institutskaya 4, 142290 Pushchino, Moscow Region, Russian Federation
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27
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Yin S, Jiang H, Chen D, Murchie AIH. Substrate recognition and modification by the nosiheptide resistance methyltransferase. PLoS One 2015; 10:e0122972. [PMID: 25910005 PMCID: PMC4409310 DOI: 10.1371/journal.pone.0122972] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 02/11/2015] [Indexed: 11/29/2022] Open
Abstract
Background The proliferation of antibiotic resistant pathogens is an increasing threat to the general public. Resistance may be conferred by a number of mechanisms including covalent or mutational modification of the antibiotic binding site, covalent modification of the drug, or the over-expression of efflux pumps. The nosiheptide resistance methyltransferase (NHR) confers resistance to the thiazole antibiotic nosiheptide in the nosiheptide producer organism Streptomyces actuosus through 2ʹO-methylation of 23S rRNA at the nucleotide A1067. Although the crystal structures of NHR and the closely related thiostrepton-resistance methyltransferase (TSR) in complex with the cofactor S-Adenosyl-L-methionine (SAM) are available, the principles behind NHR substrate recognition and catalysis remain unclear. Methodology/Principal Findings We have analyzed the binding interactions between NHR and model 58 and 29 nucleotide substrate RNAs by gel electrophoresis mobility shift assays (EMSA) and fluorescence anisotropy. We show that the enzyme binds to RNA as a dimer. By constructing a hetero-dimer complex composed of one wild-type subunit and one inactive mutant NHR-R135A subunit, we show that only one functional subunit of the NHR homodimer is required for its enzymatic activity. Mutational analysis suggests that the interactions between neighbouring bases (G1068 and U1066) and A1067 have an important role in methyltransfer activity, such that the substitution of a deoxy sugar spacer (5ʹ) to the target nucleotide achieved near wild-type levels of methylation. A series of atomic substitutions at specific positions on the substrate adenine show that local base-base interactions between neighbouring bases are important for methylation. Conclusion/Significance Taken together these data suggest that local base-base interactions play an important role in aligning the substrate 2’ hydroxyl group of A1067 for methyl group transfer. Methylation of nucleic acids is playing an increasingly important role in fundamental biological processes and we anticipate that the approach outlined in this manuscript may be useful for investigating other classes of nucleic acid methyltransferases.
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Affiliation(s)
- Sitao Yin
- Key Laboratory of Molecular Medicine, the Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai 200032, PR China
- Institutes of Biomedical Sciences, Fudan University Shanghai Medical College, Shanghai 200032, PR China
| | - Hengyi Jiang
- Key Laboratory of Molecular Medicine, the Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai 200032, PR China
- Institutes of Biomedical Sciences, Fudan University Shanghai Medical College, Shanghai 200032, PR China
| | - Dongrong Chen
- Key Laboratory of Molecular Medicine, the Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai 200032, PR China
- Institutes of Biomedical Sciences, Fudan University Shanghai Medical College, Shanghai 200032, PR China
- * E-mail: (AM); (DC)
| | - Alastair I. H. Murchie
- Key Laboratory of Molecular Medicine, the Ministry of Education, Department of Biochemistry and Molecular Biology, Fudan University Shanghai Medical College, Shanghai 200032, PR China
- Institutes of Biomedical Sciences, Fudan University Shanghai Medical College, Shanghai 200032, PR China
- * E-mail: (AM); (DC)
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28
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Rau MJ, Hall KB. 2-Aminopurine Fluorescence as a Probe of Local RNA Structure and Dynamics and Global Folding. Methods Enzymol 2015; 558:99-124. [PMID: 26068739 DOI: 10.1016/bs.mie.2015.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The biology of an RNA is encoded in its structure and dynamics, whether that be binding to a protein, binding to another RNA, enzymatic catalysis, or becoming a substrate. In solution, most RNA molecules are sampling conformations, and their structures are best described as conformational ensembles. For larger RNAs, experiments that can describe the conformations of their domains can be particularly daunting, especially when the RNA is novel and not well characterized. Here, we explain how we have used site-specific 2-aminopurine as a fluorescent probe of the secondary and tertiary structures of a 60 nucleotide RNA, and what new findings we have about its Mg(2+)-dependent conformational changes. We focus on this RNA from prokaryotic ribosome as a proof of concept as well as a research project. Its tertiary structure is known from a cocrystal, and its secondary structure is modeled from phylogenetic conservation, but there are virtually no data describing the motions of its nucleotides in solution, or its folding kinetics. It is a perfect system to illustrate the unique information that comes from a comprehensive fluorescence study of this intricate RNA.
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Affiliation(s)
- Michael J Rau
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri, USA
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University Medical School, St. Louis, Missouri, USA.
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Bousset L, Mary C, Brooks MA, Scherrer A, Strub K, Cusack S. Crystal structure of a signal recognition particle Alu domain in the elongation arrest conformation. RNA (NEW YORK, N.Y.) 2014; 20:1955-1962. [PMID: 25336584 PMCID: PMC4238359 DOI: 10.1261/rna.047209.114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 09/04/2014] [Indexed: 06/04/2023]
Abstract
The signal recognition particle (SRP) is a conserved ribonucleoprotein particle that targets membrane and secreted proteins to translocation channels in membranes. In eukaryotes, the Alu domain, which comprises the 5' and 3' extremities of the SRP RNA bound to the SRP9/14 heterodimer, is thought to interact with the ribosome to pause translation elongation during membrane docking. We present the 3.2 Å resolution crystal structure of a chimeric Alu domain, comprising Alu RNA from the archaeon Pyrococcus horikoshii bound to the human Alu binding proteins SRP9/14. The structure reveals how intricate tertiary interactions stabilize the RNA 5' domain structure and how an extra, archaeal-specific, terminal stem helps constrain the Alu RNA into the active closed conformation. In this conformation, highly conserved noncanonical base pairs allow unusually tight side-by-side packing of 5' and 3' RNA stems within the SRP9/14 RNA binding surface. The biological relevance of this structure is confirmed by showing that a reconstituted full-length chimeric archaeal-human SRP is competent to elicit elongation arrest in vitro. The structure will be useful in refining our understanding of how the SRP Alu domain interacts with the ribosome.
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Affiliation(s)
- Luc Bousset
- European Molecular Biology Laboratory, Grenoble Outstation, 38042 Grenoble Cedex 9, France
| | - Camille Mary
- Département de Biologie Cellulaire, Université de Genève, Sciences III, 1211 Geneva 4, Switzerland
| | - Mark A Brooks
- European Molecular Biology Laboratory, Grenoble Outstation, 38042 Grenoble Cedex 9, France
| | - Anne Scherrer
- Département de Biologie Cellulaire, Université de Genève, Sciences III, 1211 Geneva 4, Switzerland
| | - Katharina Strub
- Département de Biologie Cellulaire, Université de Genève, Sciences III, 1211 Geneva 4, Switzerland
| | - Stephen Cusack
- European Molecular Biology Laboratory, Grenoble Outstation, 38042 Grenoble Cedex 9, France
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30
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Kuiper EG, Conn GL. Binding induced RNA conformational changes control substrate recognition and catalysis by the thiostrepton resistance methyltransferase (Tsr). J Biol Chem 2014; 289:26189-26200. [PMID: 25086036 DOI: 10.1074/jbc.m114.574780] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Ribosomal RNA (rRNA) post-transcriptional modifications are essential for ribosome maturation, translational fidelity, and are one mechanism used by both antibiotic-producing and pathogenic bacteria to resist the effects of antibiotics that target the ribosome. The thiostrepton producer Streptomyces azureus prevents self-intoxication by expressing the thiostrepton-resistance methyltransferase (Tsr), which methylates the 2'-hydroxyl of 23 S rRNA nucleotide adenosine 1067 within the thiostrepton binding site. Tsr is a homodimer with each protomer containing an L30e-like amino-terminal domain (NTD) and a SPOUT methyltransferase family catalytic carboxyl-terminal domain (CTD). We show that both enzyme domains are required for high affinity RNA substrate binding. The Tsr-CTD has intrinsic, weak RNA affinity that is necessary to direct the specific high-affinity Tsr-RNA interaction via NTDs, which have no detectable RNA affinity in isolation. RNA structure probing experiments identify the Tsr footprint on the RNA and structural changes in the substrate, induced specifically upon NTD binding, which are necessary for catalysis by the CTD. Additionally, we identify a key amino acid in each domain responsible for CTD-RNA binding and the observed NTD-dependent RNA structural changes. These studies allow us to develop a model for Tsr-RNA interaction in which the coordinated substrate recognition of each Tsr structural domain is an obligatory pre-catalytic recognition event. Our findings underscore the complexity of substrate recognition by RNA modification enzymes and the potential for direct involvement of the RNA substrate in controlling the process of its modification.
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Affiliation(s)
- Emily G Kuiper
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322.
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Abstract
RNA dynamics play a fundamental role in many cellular functions. However, there is no general framework to describe these complex processes, which typically consist of many structural maneuvers that occur over timescales ranging from picoseconds to seconds. Here, we classify RNA dynamics into distinct modes representing transitions between basins on a hierarchical free-energy landscape. These transitions include large-scale secondary-structural transitions at >0.1-s timescales, base-pair/tertiary dynamics at microsecond-to-millisecond timescales, stacking dynamics at timescales ranging from nanoseconds to microseconds, and other "jittering" motions at timescales ranging from picoseconds to nanoseconds. We review various modes within these three different tiers, the different mechanisms by which they are used to regulate function, and how they can be coupled together to achieve greater functional complexity.
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32
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Liu X, Zheng M, Wang R, Wang R, An L, Rodermel SR, Yu F. Genetic interactions reveal that specific defects of chloroplast translation are associated with the suppression of var2-mediated leaf variegation. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2013; 55:979-93. [PMID: 23721655 DOI: 10.1111/jipb.12078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/21/2013] [Indexed: 05/09/2023]
Abstract
Arabidopsis thaliana L. yellow variegated (var2) mutant is defective in a chloroplast FtsH family metalloprotease, AtFtsH2/VAR2, and displays an intriguing green and white leaf variegation. This unique var2-mediated leaf variegation offers a simple yet powerful tool for dissecting the genetic regulation of chloroplast development. Here, we report the isolation and characterization of a new var2 suppressor gene, SUPPRESSOR OF VARIEGATION8 (SVR8), which encodes a putative chloroplast ribosomal large subunit protein, L24. Mutations in SVR8 suppress var2 leaf variegation at ambient temperature and partially suppress the cold-induced chlorosis phenotype of var2. Loss of SVR8 causes unique chloroplast rRNA processing defects, particularly the 23S-4.5S dicistronic precursor. The recovery of the major abnormal processing site in svr8 23S-4.5S precursor indicate that it does not lie in the same position where SVR8/L24 binds on the ribosome. Surprisingly, we found that the loss of a chloroplast ribosomal small subunit protein, S21, results in aberrant chloroplast rRNA processing but not suppression of var2 variegation. These findings suggest that the disruption of specific aspects of chloroplast translation, rather than a general impairment in chloroplast translation, suppress var2 variegation and the existence of complex genetic interactions in chloroplast development.
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Affiliation(s)
- Xiayan Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, 712100, China
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33
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Trachman RJ, Draper DE. Comparison of interactions of diamine and Mg²⁺ with RNA tertiary structures: similar versus differential effects on the stabilities of diverse RNA folds. Biochemistry 2013; 52:5911-9. [PMID: 23899366 PMCID: PMC3809084 DOI: 10.1021/bi400529q] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cations play a large role in stabilizing the native state of RNA in vivo. In addition to Mg²⁺, putrescine²⁺ is an abundant divalent cation in bacterial cells, but its effect on the folding of RNA tertiary structure has not been widely explored. In this study, we look at how the stabilities of four structured RNAs, each with a different degree of dependence on K⁺ and Mg²⁺, are affected by putrescine²⁺ relative to Mg²⁺. Through the use of thermal melts, we observe that (i) at a given concentration, putrescine²⁺ is less effective than Mg²⁺ at stabilizing RNA, (ii) the stability imparted to RNA by various diamines is a function of charge density (average separation distance between charges) as well as the flexibility of the counterion, and (iii) when Mg²⁺ is already present in a buffer, further addition of putrescine²⁺ may either destabilize or stabilize RNA structure, depending on whether the native RNA does or does not chelate Mg²⁺ ion, respectively. At ion concentrations likely to be found in vivo, the effect of putrescine²⁺ on the free energy of folding of an RNA tertiary structure is probably quite small compared to that of Mg²⁺, but the ability of mixed Mg²⁺/putrescine²⁺ environments to (in effect) discriminate between different RNA architectures suggests that, in some cells, the evolution of functional RNA structures may have been influenced by the presence of putrescine²⁺.
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Affiliation(s)
| | - David E. Draper
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218
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34
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Belotserkovskii BP, Mirkin SM, Hanawalt PC. DNA sequences that interfere with transcription: implications for genome function and stability. Chem Rev 2013; 113:8620-37. [PMID: 23972098 DOI: 10.1021/cr400078y] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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35
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Kwan JJ, Smirnova E, Khazai S, Evanics F, Maxwell KL, Donaldson LW. The solution structures of two prophage homologues of the bacteriophage λ Ea8.5 protein reveal a newly discovered hybrid homeodomain/zinc-finger fold. Biochemistry 2013; 52:3612-4. [PMID: 23672713 DOI: 10.1021/bi400543w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A cluster of genes in the exoxis region of bacteriophage λ are capable of inhibiting the initiation of DNA synthesis in Escherichia coli. The most indispensible gene in this region is ea8.5. Here, we report the nuclear magnetic resonance structures of two ea8.5 orthologs from enteropathogenic E. coli and Pseudomonas putida prophages. Both proteins are characterized by a fused homeodomain/zinc-finger fold that escaped detection by primary sequence search methods. While these folds are both associated with a nucleic acid binding function, the amino acid composition suggests otherwise, leading to the possibility that Ea8.5 associates with other viral and host proteins.
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Affiliation(s)
- Jamie J Kwan
- Department of Biology, York University , 4700 Keele Street, Toronto, ON M3J1P3, Canada
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36
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Hori N, Takada S. Coarse-Grained Structure-Based Model for RNA-Protein Complexes Developed by Fluctuation Matching. J Chem Theory Comput 2012; 8:3384-94. [DOI: 10.1021/ct300361j] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Naoto Hori
- Department of Biophysics,
Graduate
School of Science, Kyoto University, Kyoto, Japan
| | - Shoji Takada
- Department of Biophysics,
Graduate
School of Science, Kyoto University, Kyoto, Japan
- Core Research for Evolutional
Science and Technology, Japan Science and Technology Agency, Japan
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37
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Sudhamalla B, Yadaiah M, Ramakrishna D, Bhuyan AK. Cysteine protease attribute of eukaryotic ribosomal protein S4. Biochim Biophys Acta Gen Subj 2012; 1820:1535-42. [PMID: 22579920 DOI: 10.1016/j.bbagen.2012.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/25/2012] [Accepted: 05/03/2012] [Indexed: 12/29/2022]
Abstract
BACKGROUND Ribosomal proteins often carry out extraribosomal functions. The protein S4 from the smaller subunit of Escherichia coli, for instance, regulates self synthesis and acts as a transcription factor. In humans, S4 might be involved in Turner syndrome. Recent studies also associate many ribosomal proteins with malignancy, and cell death and survival. The list of extraribosomal functions of ribosomal proteins thus continues to grow. METHODS Enzymatic action of recombinant wheat S4 on fluorogenic peptide substrates Ac-XEXD↓-AFC (N-acetyl-residue-Glu-residue-Asp-7-amino-4-trifluoromethylcoumarin) and Z-FR↓-AMC (N-CBZ-Phe-Arg-aminomethylcoumarin) as well as proteins has been examined under a variety of solution conditions. RESULTS Eukaryotic ribosomal protein S4 is an endoprotease exhibiting all characteristics of cysteine proteases. The K(m) value for the cleavage of Z-FR↓-AMC by a cysteine mutant (C41F) is about 70-fold higher relative to that for the wild-type protein under identical conditions, implying that S4 is indeed a cysteine protease. Interestingly, activity responses of the S4 protein and caspases toward environmental parameters, including pH, temperature, ionic strength, and Mg(2+) and Zn(2+) concentrations, are quite similar. Respective kinetic constants for their cleavage action on Ac-LEHD↓-AFC are also similar. However, S4 cannot be a caspase, because unlike the latter it also hydrolyzes the cathepsin substrate Z-FR↓-AMC. GENERAL SIGNIFICANCE The eukaryotic S4 is a generic cysteine protease capable of hydrolyzing a broad spectrum of synthetic substrates and proteins. The enzyme attribute of eukaryotic ribosomal protein S4 is a new phenomenon. Its possible involvement in cell growth and proliferations are presented in the light of known extraribosomal roles of ribosomal proteins.
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Affiliation(s)
- Babu Sudhamalla
- School of Chemistry, University of Hyderabad, Hyderabad 500 046, India
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38
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Jalalirad M, Saadatmand J, Laughrea M. Dominant role of the 5' TAR bulge in dimerization of HIV-1 genomic RNA, but no evidence of TAR-TAR kissing during in vivo virus assembly. Biochemistry 2012; 51:3744-58. [PMID: 22482513 DOI: 10.1021/bi300111p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The 5' untranslated region of HIV-1 genomic RNA (gRNA) contains two stem-loop structures that appear to be equally important for gRNA dimerization: the 57-nucleotide 5' TAR, at the very 5' end, and the 35-nucleotide SL1 (nucleotides 243-277). SL1 is well-known for containing the dimerization initiation site (DIS) in its apical loop. The DIS is a six-nucleotide palindrome. Here, we investigated the mechanism of TAR-directed gRNA dimerization. We found that the trinucleotide bulge (UCU24) of the 5' TAR has dominant impacts on both formation of HIV-1 RNA dimers and maturation of the formed dimers. The ΔUCU trinucleotide deletion strongly inhibited the first process and blocked the other, thus impairing gRNA dimerization as severely as deletion of the entire 5' TAR, and more severely than deletion of the DIS, inactivation of the viral protease, or most severe mutations in the nucleocapsid protein. The apical loop of TAR contains a 10-nucleotide palindrome that has been postulated to stimulate gRNA dimerization by a TAR-TAR kissing mechanism analogous to the one used by SL1 to stimulate dimerization. Using mutations that strongly destabilize formation of the TAR palindrome duplex, as well as compensatory mutations that restore duplex formation to a wild-type-like level, we found no evidence of TAR-TAR kissing, even though mutations nullifying the kissing potential of the TAR palindrome could impair dimerization by a mechanism other than hindering of SL1. However, nullifying the kissing potential of TAR had much less severe effects than ΔUCU. By not uncovering a dimerization mechanism intrinsic to TAR, our data suggest that TAR mutations exert their effect 3' of TAR, yet not on SL1, because TAR and SL1 mutations have synergistic effects on gRNA dimerization.
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Affiliation(s)
- Mohammad Jalalirad
- McGill AIDS Center, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada
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39
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Mustoe AM, Bailor MH, Teixeira RM, Brooks CL, Al-Hashimi HM. New insights into the fundamental role of topological constraints as a determinant of two-way junction conformation. Nucleic Acids Res 2011; 40:892-904. [PMID: 21937512 PMCID: PMC3258142 DOI: 10.1093/nar/gkr751] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent studies have shown that topological constraints encoded at the RNA secondary structure level involving basic steric and stereochemical forces can significantly restrict the orientations sampled by helices across two-way RNA junctions. Here, we formulate these topological constraints in greater quantitative detail and use this topological framework to rationalize long-standing but poorly understood observations regarding the basic behavior of RNA two-way junctions. Notably, we show that the asymmetric nature of the A-form helix and the finite length of a bulge provide a physical basis for the experimentally observed directionality and bulge-length amplitude dependence of bulge induced inter-helical bends. We also find that the topologically allowed space can be modulated by variations in sequence, particularly with the addition of non-canonical GU base pairs at the junction, and, surprisingly, by the length of the 5′ and 3′ helices. A survey of two-way RNA junctions in the protein data bank confirms that junction residues have a strong preference to adopt looped-in, non-canonically base-paired conformations, providing a route for extending our bulge-directed framework to internal loop motifs and implying a simplified link between secondary and tertiary structure. Finally, our results uncover a new simple mechanism for coupling junction-induced topological constraints with tertiary interactions.
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Affiliation(s)
- Anthony M Mustoe
- Departments of Chemistry & Biophysics, The University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA
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40
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Leipply D, Draper DE. Evidence for a thermodynamically distinct Mg2+ ion associated with formation of an RNA tertiary structure. J Am Chem Soc 2011; 133:13397-405. [PMID: 21776997 DOI: 10.1021/ja2020923] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A folding strategy adopted by some RNAs is to chelate cations in pockets or cavities, where the ions neutralize charge from solvent-inaccessible phosphate. Although such buried Mg(2+)-RNA chelates could be responsible for a significant fraction of the Mg(2+)-dependent stabilization free energy of some RNA tertiary structures, direct measurements have not been feasible because of the difficulty of finding conditions under which the free energy of Mg(2+) chelation is uncoupled from RNA folding and from unfavorable interactions with Mg(2+) ions in other environments. In a 58mer rRNA fragment, we have used a high-affinity thermophilic ribosomal protein to trap the RNA in a structure nearly identical to native; Mg(2+)- and protein-stabilized structures differ in the solvent exposure of a single nucleotide located at the chelation site. Under these conditions, titration of a high affinity chelation site takes place in a micromolar range of Mg(2+) concentration, and is partially resolved from the accumulation of Mg(2+) in the ion atmosphere. From these experiments, we estimate the total and site-specific Mg(2+)-RNA interaction free energies over the range of accessed Mg(2+) concentrations. At 0.1 mM Mg(2+) and 60 mM K(+), specific site binding contributes ∼-3 kcal/mol of the total Mg(2+) interaction free energy of ∼-13 kcal/mol from all sources; at higher Mg(2+) concentrations the site-binding contribution becomes a smaller proportion of the total (-4.5 vs -33 kcal/mol). Under approximately physiological ionic conditions, the specific binding site will be saturated but will provide only a fraction of the total free energy of Mg(2+)-RNA interactions.
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Affiliation(s)
- Desirae Leipply
- Department of Biophysics, Johns Hopkins University Baltimore, Maryland 21218, United States
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41
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Single-molecule fluorescence measurements of ribosomal translocation dynamics. Mol Cell 2011; 42:367-77. [PMID: 21549313 DOI: 10.1016/j.molcel.2011.03.024] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 12/01/2010] [Accepted: 03/08/2011] [Indexed: 11/22/2022]
Abstract
We employ single-molecule fluorescence resonance energy transfer (smFRET) to study structural dynamics over the first two elongation cycles of protein synthesis, using ribosomes containing either Cy3-labeled ribosomal protein L11 and A- or P-site Cy5-labeled tRNA or Cy3- and Cy5-labeled tRNAs. Pretranslocation (PRE) complexes demonstrate fluctuations between classical and hybrid forms, with concerted motions of tRNAs away from L11 and from each other when classical complex converts to hybrid complex. EF-G⋅GTP binding to both hybrid and classical PRE complexes halts these fluctuations prior to catalyzing translocation to form the posttranslocation (POST) complex. EF-G dependent translocation from the classical PRE complex proceeds via transient formation of a short-lived hybrid intermediate. A-site binding of either EF-G to the PRE complex or of aminoacyl-tRNA⋅EF-Tu ternary complex to the POST complex markedly suppresses ribosome conformational lability.
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42
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Liu B, Diamond JM, Mathews DH, Turner DH. Fluorescence competition and optical melting measurements of RNA three-way multibranch loops provide a revised model for thermodynamic parameters. Biochemistry 2011; 50:640-53. [PMID: 21133351 PMCID: PMC3032278 DOI: 10.1021/bi101470n] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
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Three-way multibranch loops (junctions) are common in RNA secondary structures. Computer algorithms such as RNAstructure and MFOLD do not consider the identity of unpaired nucleotides in multibranch loops when predicting secondary structure. There is limited experimental data, however, to parametrize this aspect of these algorithms. In this study, UV optical melting and a fluorescence competition assay are used to measure stabilities of multibranch loops containing up to five unpaired adenosines or uridines or a loop E motif. These results provide a test of our understanding of the factors affecting multibranch loop stability and provide revised parameters for predicting stability. The results should help to improve predictions of RNA secondary structure.
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Affiliation(s)
- Biao Liu
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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43
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Nwugo CC, Huerta AJ. The Effect of Silicon on the Leaf Proteome of Rice (Oryza sativa L.) Plants under Cadmium-Stress. J Proteome Res 2010; 10:518-28. [DOI: 10.1021/pr100716h] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Chika C. Nwugo
- Departments of Microbiology and Botany, Miami University, Oxford, Ohio 45056, United States
| | - Alfredo J. Huerta
- Departments of Microbiology and Botany, Miami University, Oxford, Ohio 45056, United States
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44
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Abstract
RNA molecules take advantage of prevalent structural motifs to fold and assemble into well-defined 3D architectures. The A-minor junction is a class of RNA motifs that specifically controls coaxial stacking of helices in natural RNAs. A sensitive self-assembling supra-molecular system was used as an assay to compare several natural and previously unidentified A-minor junctions by native polyacrylamide gel electrophoresis and atomic force microscopy. This class of modular motifs follows a topological rule that can accommodate a variety of interchangeable A-minor interactions with distinct local structural motifs. Overall, two different types of A-minor junctions can be distinguished based on their functional self-assembling behavior: one group makes use of triloops or GNRA and GNRA-like loops assembling with helices, while the other takes advantage of more complex tertiary receptors specific for the loop to gain higher stability. This study demonstrates how different structural motifs of RNA can contribute to the formation of topologically equivalent helical stacks. It also exemplifies the need of classifying RNA motifs based on their tertiary structural features rather than secondary structural features. The A-minor junction rule can be used to facilitate tertiary structure prediction of RNAs and rational design of RNA parts for nanobiotechnology and synthetic biology.
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Affiliation(s)
- Cody Geary
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510, USA
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45
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Harris S, Schroeder SJ. Nuclear magnetic resonance structure of the prohead RNA E-loop hairpin. Biochemistry 2010; 49:5989-97. [PMID: 20550192 DOI: 10.1021/bi100393r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Bacillus subtilis phage phi29 packaging motor requires prohead RNA for genome encapsidation. The nuclear magnetic resonance structure of the prohead RNA E-loop hairpin, r(5'AUUGAGUU), is presented and compared to predictions from MC-SYM. The prohead RNA E-loop hairpins contain sequences similar to rRNA hairpins. Comparison of predicted and experimentally determined prohead and ribosomal hairpin structures reveals that sequence similarity is a stronger determinant of hairpin structural similarity than grouping similar types of RNA. All the hairpins contain a U-turn motif but differ in the first noncanonical pair and backbone orientation. These structures provide benchmarks for further improvements in RNA structure predictions from sequence.
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Affiliation(s)
- Steven Harris
- Department of Chemistry and Biochemistry, University of Oklahoma, 620 Parrington Oval, Norman, Oklahoma 73019, USA
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46
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Yang H, Wang Z, Shen Y, Wang P, Jia X, Zhao L, Zhou P, Gong R, Li Z, Yang Y, Chen D, Murchie AIH, Xu Y. Crystal Structure of the Nosiheptide-Resistance Methyltransferase of Streptomyces actuosus. Biochemistry 2010; 49:6440-50. [DOI: 10.1021/bi1005915] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Huirong Yang
- Cancer Institute, Shanghai Cancer Center, Fudan University, and Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- School of Life Sciences, Fudan University, 220 Han-Dan Road, Shanghai 200433, China
| | - Zhe Wang
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- Department of Pharmacy, Fudan University, Shanghai 201203, China
| | - Yan Shen
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- Department of Pharmacy, Fudan University, Shanghai 201203, China
| | - Ping Wang
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- School of Life Sciences, Fudan University, 220 Han-Dan Road, Shanghai 200433, China
| | - Xu Jia
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- Department of Pharmacy, Fudan University, Shanghai 201203, China
| | - Liang Zhao
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- Department of Chemistry, Fudan University, Han-Dan Road, Shanghai 200433, China
| | - Pei Zhou
- Department of Pharmacy, Fudan University, Shanghai 201203, China
| | - Rui Gong
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- School of Life Sciences, Fudan University, 220 Han-Dan Road, Shanghai 200433, China
| | - Ze Li
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- School of Life Sciences, Fudan University, 220 Han-Dan Road, Shanghai 200433, China
| | - Ying Yang
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- School of Life Sciences, Fudan University, 220 Han-Dan Road, Shanghai 200433, China
| | - Dongrong Chen
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- Department of Pharmacy, Fudan University, Shanghai 201203, China
| | - Alastair I. H. Murchie
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- Department of Pharmacy, Fudan University, Shanghai 201203, China
| | - Yanhui Xu
- Cancer Institute, Shanghai Cancer Center, Fudan University, and Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, China
- Institutes of Biomedical Sciences, Fudan University, 130 Dong-An Road, Shanghai 200032, China
- School of Life Sciences, Fudan University, 220 Han-Dan Road, Shanghai 200433, China
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Baumann S, Schoof S, Bolten M, Haering C, Takagi M, Shin-ya K, Arndt HD. Molecular Determinants of Microbial Resistance to Thiopeptide Antibiotics. J Am Chem Soc 2010; 132:6973-81. [DOI: 10.1021/ja909317n] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sascha Baumann
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Sebastian Schoof
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Marcel Bolten
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Claudia Haering
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Motoki Takagi
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Kazuo Shin-ya
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
| | - Hans-Dieter Arndt
- Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund, Germany, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany, and Biomedicinal Information Research Center (BIRC), 2-4-7 Aomi, Koto-ku, Tokyo 135-0064, Japan
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de la Peña M, Dufour D, Gallego J. Three-way RNA junctions with remote tertiary contacts: a recurrent and highly versatile fold. RNA (NEW YORK, N.Y.) 2009; 15:1949-64. [PMID: 19741022 PMCID: PMC2764472 DOI: 10.1261/rna.1889509] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Three-way junction RNAs adopt a recurrent Y shape when two of the helices form a coaxial stack and the third helix establishes one or more tertiary contacts several base pairs away from the junction. In this review, the structure, distribution, and functional relevance of these motifs are examined. Structurally, the folds exhibit conserved junction topologies, and the distal tertiary interactions play a crucial role in determining the final shape of the structures. The junctions and remote tertiary contacts behave as flexible hinge motifs that respond to changes in the other region, providing these folds with switching mechanisms that have been shown to be functionally useful in a variety of contexts. In addition, the juxtaposition of RNA domains at the junction and at the distal tertiary complexes enables the RNA helices to adopt unusual conformations that are frequently used by proteins, RNA molecules, and antibiotics as platforms for specific binding. As a consequence of these properties, Y-shaped junctions are widely distributed in all kingdoms of life, having been observed in small naked RNAs such as riboswitches and ribozymes or embedded in complex ribonucleoprotein systems like ribosomal RNAs, RNase P, or the signal recognition particle. In all cases, the folds were found to play an essential role for the functioning or assembly of the RNA or ribonucleoprotein systems that contain them.
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Affiliation(s)
- Marcos de la Peña
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), 46022 Valencia, Spain
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Huang W, Kim J, Jha S, Aboul-ela F. A mechanism for S-adenosyl methionine assisted formation of a riboswitch conformation: a small molecule with a strong arm. Nucleic Acids Res 2009; 37:6528-39. [PMID: 19720737 PMCID: PMC2770654 DOI: 10.1093/nar/gkp664] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The S-adenosylmethionine-1 (SAM-I) riboswitch mediates expression of proteins involved in sulfur metabolism via formation of alternative conformations in response to binding by SAM. Models for kinetic trapping of the RNA in the bound conformation require annealing of nonadjacent mRNA segments during a transcriptional pause. The entropic cost required to bring nonadjacent segments together should slow the folding process. To address this paradox, we performed molecular dynamics simulations on the SAM-I riboswitch aptamer domain with and without SAM, starting with the X-ray coordinates of the SAM-bound RNA. Individual trajectories are 200 ns, among the longest reported for an RNA of this size. We applied principle component analysis (PCA) to explore the global dynamics differences between these two trajectories. We observed a conformational switch between a stacked and nonstacked state of a nonadjacent dinucleotide in the presence of SAM. In the absence of SAM the coordination between a bound magnesium ion and the phosphate of A9, one of the nucleotides involved in the dinucleotide stack, is destabilized. An electrostatic potential map reveals a 'hot spot' at the Mg binding site in the presence of SAM. These results suggest that SAM binding helps to position J1/2 in a manner that is favorable for P1 helix formation.
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Affiliation(s)
- Wei Huang
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA
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Keene FR, Smith JA, Collins JG. Metal complexes as structure-selective binding agents for nucleic acids. Coord Chem Rev 2009. [DOI: 10.1016/j.ccr.2009.01.004] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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