1
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He W, Henning-Knechtel A, Kirmizialtin S. Visualizing RNA Structures by SAXS-Driven MD Simulations. FRONTIERS IN BIOINFORMATICS 2022; 2:781949. [PMID: 36304317 PMCID: PMC9580860 DOI: 10.3389/fbinf.2022.781949] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/04/2022] [Indexed: 12/26/2022] Open
Abstract
The biological role of biomolecules is intimately linked to their structural dynamics. Experimental or computational techniques alone are often insufficient to determine accurate structural ensembles in atomic detail. We use all-atom molecular dynamics (MD) simulations and couple it to small-angle X-ray scattering (SAXS) experiments to resolve the structural dynamics of RNA molecules. To accomplish this task, we utilize a set of re-weighting and biasing techniques tailored for RNA molecules. To showcase our approach, we study two RNA molecules: a riboswitch that shows structural variations upon ligand binding, and a two-way junction RNA that displays structural heterogeneity and sensitivity to salt conditions. Integration of MD simulations and experiments allows the accurate construction of conformational ensembles of RNA molecules. We observe a dynamic change of the SAM-I riboswitch conformations depending on its binding partners. The binding of SAM and Mg2+ cations stabilizes the compact state. The absence of Mg2+ or SAM leads to the loss of tertiary contacts, resulting in a dramatic expansion of the riboswitch conformations. The sensitivity of RNA structures to the ionic strength demonstrates itself in the helix junction helix (HJH). The HJH shows non-monotonic compaction as the ionic strength increases. The physics-based picture derived from the experimentally guided MD simulations allows biophysical characterization of RNA molecules. All in all, SAXS-guided MD simulations offer great prospects for studying RNA structural dynamics.
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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, United States
| | - Anja Henning-Knechtel
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Serdal Kirmizialtin
- Chemistry Program, Science Division, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
- *Correspondence: Serdal Kirmizialtin,
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2
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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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3
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Jeevanandam J, Tan KX, Danquah MK, Guo H, Turgeson A. Advancing Aptamers as Molecular Probes for Cancer Theranostic Applications-The Role of Molecular Dynamics Simulation. Biotechnol J 2020; 15:e1900368. [PMID: 31840436 DOI: 10.1002/biot.201900368] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 12/06/2019] [Indexed: 12/24/2022]
Abstract
Theranostics cover emerging technologies for cell biomarking for disease diagnosis and targeted introduction of drug ingredients to specific malignant sites. Theranostics development has become a significant biomedical research endeavor for effective diagnosis and treatment of diseases, especially cancer. An efficient biomarking and targeted delivery strategy for theranostic applications requires effective molecular coupling of binding ligands with high affinities to specific receptors on the cancer cell surface. Bioaffinity offers a unique mechanism to bind specific target and receptor molecules from a range of non-targets. The binding efficacy depends on the specificity of the affinity ligand toward the target molecule even at low concentrations. Aptamers are fragments of genetic materials, peptides, or oligonucleotides which possess enhanced specificity in targeting desired cell surface receptor molecules. Aptamer-target binding results from several inter-molecular interactions including hydrogen bond formation, aromatic stacking of flat moieties, hydrophobic interaction, electrostatic, and van der Waals interactions. Advancements in Systematic Evolution of Ligands by Exponential Enrichment (SELEX) assay has created the opportunity to artificially generate aptamers that specifically bind to desired cancer and tumor surface receptors with high affinities. This article discusses the potential application of molecular dynamics (MD) simulation to advance aptamer-mediated receptor targeting in targeted cancer therapy. MD simulation offers real-time analysis of the molecular drivers of the aptamer-receptor binding and generate optimal receptor binding conditions for theranostic applications. The article also provides an overview of different cancer types with focus on receptor biomarking and targeted treatment approaches, conventional molecular probes, and aptamers that have been explored for cancer cells targeting.
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Affiliation(s)
- Jaison Jeevanandam
- Department of Chemical Engineering, Faculty of Engineering and Science, Curtin University, Miri, Sarawak, 98009, Malaysia
| | - Kei Xian Tan
- School of Materials Science & Engineering, Nanyang Technological University, Singapore, 639798
| | | | - Haobo Guo
- Department of Computer Science and Engineering, University of Tennessee, Chattanooga, TN, 37403, USA.,SimCenter, University of Tennessee, Chattanooga, TN, 37403, USA
| | - Andrew Turgeson
- Chemical Engineering Department, University of Tennessee, Chattanooga, TN, 37403, USA
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4
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Roy S, Hennelly SP, Lammert H, Onuchic JN, Sanbonmatsu KY. Magnesium controls aptamer-expression platform switching in the SAM-I riboswitch. Nucleic Acids Res 2019; 47:3158-3170. [PMID: 30605518 PMCID: PMC6451092 DOI: 10.1093/nar/gky1311] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/19/2018] [Accepted: 12/28/2018] [Indexed: 12/23/2022] Open
Abstract
Investigations of most riboswitches remain confined to the ligand-binding aptamer domain. However, during the riboswitch mediated transcription regulation process, the aptamer domain and the expression platform compete for a shared strand. If the expression platform dominates, an anti-terminator helix is formed, and the transcription process is active (ON state). When the aptamer dominates, transcription is terminated (OFF state). Here, we use an expression platform switching experimental assay and structure-based electrostatic simulations to investigate this ON-OFF transition of the full length SAM-I riboswitch and its magnesium concentration dependence. Interestingly, we find the ratio of the OFF population to the ON population to vary non-monotonically as magnesium concentration increases. Upon addition of magnesium, the aptamer domain pre-organizes, populating the OFF state, but only up to an intermediate magnesium concentration level. Higher magnesium concentration preferentially stabilizes the anti-terminator helix, populating the ON state, relatively destabilizing the OFF state. Magnesium mediated aptamer-expression platform domain closure explains this relative destabilization of the OFF state at higher magnesium concentration. Our study reveals the functional potential of magnesium in controlling transcription of its downstream genes and underscores the importance of a narrow concentration regime near the physiological magnesium concentration ranges, striking a balance between the OFF and ON states in bacterial gene regulation.
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Affiliation(s)
- Susmita Roy
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - Scott P Hennelly
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.,New Mexico Consortium, Los Alamos, NM 87544, USA
| | - Heiko Lammert
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA
| | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77005, USA.,Departments of Physics and Astronomy, Chemistry, and Biosciences, Rice University, Houston, TX 77005, USA
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.,New Mexico Consortium, Los Alamos, NM 87544, USA
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5
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Pucci F, Schug A. Shedding light on the dark matter of the biomolecular structural universe: Progress in RNA 3D structure prediction. Methods 2019; 162-163:68-73. [DOI: 10.1016/j.ymeth.2019.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/12/2019] [Accepted: 04/22/2019] [Indexed: 11/25/2022] Open
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6
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Frezza E, Courban A, Allouche D, Sargueil B, Pasquali S. The interplay between molecular flexibility and RNA chemical probing reactivities analyzed at the nucleotide level via an extensive molecular dynamics study. Methods 2019; 162-163:108-127. [PMID: 31145972 DOI: 10.1016/j.ymeth.2019.05.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 05/22/2019] [Accepted: 05/22/2019] [Indexed: 12/20/2022] Open
Abstract
Determination of the tridimensional structure of ribonucleic acid molecules is fundamental for understanding their function in the cell. A common method to investigate RNA structures of large molecules is the use of chemical probes such as SHAPE (2'-hydroxyl acylation analyzed by primer extension) reagents, DMS (dimethyl sulfate) and CMCT (1-cyclohexyl-3-(2-morpholinoethyl) carbodiimide metho-p-toluene sulfate), the reaction of which is dependent on the local structural properties of each nucleotide. In order to understand the interplay between local flexibility, sugar pucker, canonical pairing and chemical reactivity of the probes, we performed all-atom molecular dynamics simulations on a set of RNA molecules for which both tridimensional structure and chemical probing data are available and we analyzed the correlations between geometrical parameters and the chemical reactivity. Our study confirms that SHAPE reactivity is guided by the local flexibility of the different chemical moieties but suggests that a combination of multiple parameters is needed to better understand the implications of the reactivity at the molecular level. This is also the case for DMS and CMCT for which the reactivity appears to be more complex than commonly accepted.
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Affiliation(s)
- Elisa Frezza
- Faculté de Pharmacie de Paris, Laboratoire de Cristallographie et RMN Biologiques, UMR 8015 - CNRS, Université Paris Descartes, 4 Avenue de l'Observatoire 75270 PARIS CEDEX 06, France.
| | - Antoine Courban
- Faculté de Pharmacie de Paris, Laboratoire de Cristallographie et RMN Biologiques, UMR 8015 - CNRS, Université Paris Descartes, 4 Avenue de l'Observatoire 75270 PARIS CEDEX 06, France
| | - Delphine Allouche
- Faculté de Pharmacie de Paris, Laboratoire de Cristallographie et RMN Biologiques, UMR 8015 - CNRS, Université Paris Descartes, 4 Avenue de l'Observatoire 75270 PARIS CEDEX 06, France
| | - Bruno Sargueil
- Faculté de Pharmacie de Paris, Laboratoire de Cristallographie et RMN Biologiques, UMR 8015 - CNRS, Université Paris Descartes, 4 Avenue de l'Observatoire 75270 PARIS CEDEX 06, France.
| | - Samuela Pasquali
- Faculté de Pharmacie de Paris, Laboratoire de Cristallographie et RMN Biologiques, UMR 8015 - CNRS, Université Paris Descartes, 4 Avenue de l'Observatoire 75270 PARIS CEDEX 06, France.
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7
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Sanbonmatsu KY. Large-scale simulations of nucleoprotein complexes: ribosomes, nucleosomes, chromatin, chromosomes and CRISPR. Curr Opin Struct Biol 2019; 55:104-113. [PMID: 31125796 DOI: 10.1016/j.sbi.2019.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/01/2019] [Indexed: 12/11/2022]
Abstract
Recent advances in biotechnology such as Hi-C, CRISPR/Cas9 and ribosome display have placed nucleoprotein complexes at center stage. Understanding the structural dynamics of these complexes aids in optimizing protocols and interpreting data for these new technologies. The integration of simulation and experiment has helped advance mechanistic understanding of these systems. Coarse-grained simulations, reduced-description models, and explicit solvent molecular dynamics simulations yield useful complementary perspectives on nucleoprotein complex structural dynamics. When combined with Hi-C, cryo-EM, and single molecule measurements, these simulations integrate disparate forms of experimental data into a coherent mechanism.
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8
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Hurst T, Xu X, Zhao P, Chen SJ. Quantitative Understanding of SHAPE Mechanism from RNA Structure and Dynamics Analysis. J Phys Chem B 2018; 122:4771-4783. [PMID: 29659274 DOI: 10.1021/acs.jpcb.8b00575] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) method probes RNA local structural and dynamic information at single nucleotide resolution. To gain quantitative insights into the relationship between nucleotide flexibility, RNA 3D structure, and SHAPE reactivity, we develop a 3D Structure-SHAPE Relationship model (3DSSR) to rebuild SHAPE profiles from 3D structures. The model starts from RNA structures and combines nucleotide interaction strength and conformational propensity, ligand (SHAPE reagent) accessibility, and base-pairing pattern through a composite function to quantify the correlation between SHAPE reactivity and nucleotide conformational stability. The 3DSSR model shows the relationship between SHAPE reactivity and RNA structure and energetics. Comparisons between the 3DSSR-predicted SHAPE profile and the experimental SHAPE data show correlation, suggesting that the extracted analytical function may have captured the key factors that determine the SHAPE reactivity profile. Furthermore, the theory offers an effective method to sieve RNA 3D models and exclude models that are incompatible with experimental SHAPE data.
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Affiliation(s)
- Travis Hurst
- Department of Physics, Department of Biochemistry , and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
| | - Xiaojun Xu
- Department of Physics, Department of Biochemistry , and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
| | - Peinan Zhao
- Department of Physics, Department of Biochemistry , and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
| | - Shi-Jie Chen
- Department of Physics, Department of Biochemistry , and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
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9
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Mlýnský V, Bussi G. Molecular Dynamics Simulations Reveal an Interplay between SHAPE Reagent Binding and RNA Flexibility. J Phys Chem Lett 2018; 9:313-318. [PMID: 29265824 PMCID: PMC5830694 DOI: 10.1021/acs.jpclett.7b02921] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 12/21/2017] [Indexed: 05/10/2023]
Abstract
The function of RNA molecules usually depends on their overall fold and on the presence of specific structural motifs. Chemical probing methods are routinely used in combination with nearest-neighbor models to determine RNA secondary structure. Among the available methods, SHAPE is relevant due to its capability to probe all RNA nucleotides and the possibility to be used in vivo. However, the structural determinants for SHAPE reactivity and its mechanism of reaction are still unclear. Here molecular dynamics simulations and enhanced sampling techniques are used to predict the accessibility of nucleotide analogs and larger RNA structural motifs to SHAPE reagents. We show that local RNA reconformations are crucial in allowing reagents to reach the 2'-OH group of a particular nucleotide and that sugar pucker is a major structural factor influencing SHAPE reactivity.
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Affiliation(s)
- Vojtěch Mlýnský
- Scuola Internazionale Superiore di
Studi Avanzati, SISSA, via Bonomea 265, 34136 Trieste, Italy
| | - Giovanni Bussi
- Scuola Internazionale Superiore di
Studi Avanzati, SISSA, via Bonomea 265, 34136 Trieste, Italy
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10
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Gulay SP, Bista S, Varshney A, Kirmizialtin S, Sanbonmatsu KY, Dinman JD. Tracking fluctuation hotspots on the yeast ribosome through the elongation cycle. Nucleic Acids Res 2017; 45:4958-4971. [PMID: 28334755 PMCID: PMC5416885 DOI: 10.1093/nar/gkx112] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/06/2017] [Indexed: 11/15/2022] Open
Abstract
Chemical modification was used to quantitatively determine the flexibility of nearly the entire rRNA component of the yeast ribosome through 8 discrete stages of translational elongation, revealing novel observations at the gross and fine-scales. These include (i) the bulk transfer of energy through the intersubunit bridges from the large to the small subunit after peptidyltransfer, (ii) differences in the interaction of the sarcin ricin loop with the two elongation factors and (iii) networked information exchange pathways that may functionally facilitate intra- and intersubunit coordination, including the 5.8S rRNA. These analyses reveal hot spots of fluctuations that set the stage for large-scale conformational changes essential for translocation and enable the first molecular dynamics simulation of an 80S complex. Comprehensive datasets of rRNA base flexibilities provide a unique resource to the structural biology community that can be computationally mined to complement ongoing research toward the goal of understanding the dynamic ribosome.
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Affiliation(s)
- Suna P Gulay
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Sujal Bista
- Department of Computer Science, University of Maryland, College Park, MD 20742, USA
| | - Amitabh Varshney
- Department of Computer Science, University of Maryland, College Park, MD 20742, USA
| | - Serdal Kirmizialtin
- Chemistry Program, New York University Abu Dhabi, Abu Dhabi, UAE.,The New Mexico Consortium, Los Alamos, NM 87544, USA
| | - Karissa Y Sanbonmatsu
- The New Mexico Consortium, Los Alamos, NM 87544, USA.,Theoretical Biology and Biophysics, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
| | - Jonathan D Dinman
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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11
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Roy S, Onuchic JN, Sanbonmatsu KY. Cooperation between Magnesium and Metabolite Controls Collapse of the SAM-I Riboswitch. Biophys J 2017; 113:348-359. [PMID: 28746845 DOI: 10.1016/j.bpj.2017.06.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/25/2017] [Accepted: 06/22/2017] [Indexed: 12/23/2022] Open
Abstract
The S-adenosylmethionine (SAM)-I riboswitch is a noncoding RNA that regulates the transcription termination process in response to metabolite (SAM) binding. The aptamer portion of the riboswitch may adopt an open or closed state depending on the presence of metabolite. Although the transition between the open and closed states is critical for the switching process, its atomistic details are not well understood. Using atomistic simulations, we calculate the effect of SAM and magnesium ions on the folding free energy landscape of the SAM-I riboswitch. These molecular simulation results are consistent with our previous wetlab experiments and aid in interpreting the SHAPE probing measurements. Here, molecular dynamics simulations explicitly identify target RNA motifs sensitive to magnesium ions and SAM. In the simulations, we observe that, whereas the metabolite mostly stabilizes the P1 and P3 helices, magnesium serves an important role in stabilizing a pseudoknot interaction between the P2 and P4 helices, even at high metabolite concentrations. The pseudoknot stabilization by magnesium, in combination with P1 stabilization by SAM, explains the requirement of both SAM and magnesium to form the fully collapsed metabolite-bound closed state of the SAM-I riboswitch. In the absence of SAM, frequent open-to-closed conformational transitions of the pseudoknot occur, akin to breathing. These pseudoknot fluctuations disrupt the binding site by facilitating fluctuations in the 5'-end of helix P1. Magnesium biases the landscape toward a collapsed state (preorganization) by coordinating pseudoknot and 5'-P1 fluctuations. The cooperation between SAM and magnesium in stabilizing important tertiary interactions elucidates their functional significance in transcription regulation.
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Affiliation(s)
- Susmita Roy
- Center for Theoretical Biological Physics, Chemistry, and Biosciences, Rice University, Houston, Texas
| | - José N Onuchic
- Center for Theoretical Biological Physics, Chemistry, and Biosciences, Rice University, Houston, Texas; Departments of Physics and Astronomy, Chemistry, and Biosciences, Rice University, Houston, Texas.
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico; New Mexico Consortium, Los Alamos, New Mexico.
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12
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Mlýnský V, Bussi G. Understanding in-line probing experiments by modeling cleavage of nonreactive RNA nucleotides. RNA (NEW YORK, N.Y.) 2017; 23:712-720. [PMID: 28202709 PMCID: PMC5393180 DOI: 10.1261/rna.060442.116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 02/03/2017] [Indexed: 05/25/2023]
Abstract
Ribonucleic acid (RNA) is involved in many regulatory and catalytic processes in the cell. The function of any RNA molecule is intimately related with its structure. In-line probing experiments provide valuable structural data sets for a variety of RNAs and are used to characterize conformational changes in riboswitches. However, the structural determinants that lead to differential reactivities in unpaired nucleotides have not been investigated yet. In this work, we used a combination of theoretical approaches, i.e., classical molecular dynamics simulations, multiscale quantum mechanical/molecular mechanical calculations, and enhanced sampling techniques in order to compute and interpret the differential reactivity of individual residues in several RNA motifs, including members of the most important GNRA and UNCG tetraloop families. Simulations on the multinanosecond timescale are required to converge the related free-energy landscapes. The results for uGAAAg and cUUCGg tetraloops and double helices are compared with available data from in-line probing experiments and show that the introduced technique is able to distinguish between nucleotides of the uGAAAg tetraloop based on their structural predispositions toward phosphodiester backbone cleavage. For the cUUCGg tetraloop, more advanced ab initio calculations would be required. This study is the first attempt to computationally classify chemical probing experiments and paves the way for an identification of tertiary structures based on the measured reactivity of nonreactive nucleotides.
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Affiliation(s)
- Vojtěch Mlýnský
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati (SISSA), 34136 Trieste, Italy
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13
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Jijakli K, Khraiwesh B, Fu W, Luo L, Alzahmi A, Koussa J, Chaiboonchoe A, Kirmizialtin S, Yen L, Salehi-Ashtiani K. The in vitro selection world. Methods 2016; 106:3-13. [PMID: 27312879 DOI: 10.1016/j.ymeth.2016.06.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/23/2016] [Accepted: 06/07/2016] [Indexed: 12/20/2022] Open
Abstract
Through iterative cycles of selection, amplification, and mutagenesis, in vitro selection provides the ability to isolate molecules of desired properties and function from large pools (libraries) of random molecules with as many as 10(16) distinct species. This review, in recognition of a quarter of century of scientific discoveries made through in vitro selection, starts with a brief overview of the method and its history. It further covers recent developments in in vitro selection with a focus on tools that enhance the capabilities of in vitro selection and its expansion from being purely a nucleic acids selection to that of polypeptides and proteins. In addition, we cover how next generation sequencing and modern biological computational tools are being used to complement in vitro selection experiments. On the very least, sequencing and computational tools can translate the large volume of information associated with in vitro selection experiments to manageable, analyzable, and exploitable information. Finally, in vivo selection is briefly compared and contrasted to in vitro selection to highlight the unique capabilities of each method.
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Affiliation(s)
- Kenan Jijakli
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Basel Khraiwesh
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Weiqi Fu
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Liming Luo
- Department of Pathology & Immunology, Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Amnah Alzahmi
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Joseph Koussa
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Amphun Chaiboonchoe
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Serdal Kirmizialtin
- Chemistry Program, Division of Science and Math, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates
| | - Laising Yen
- Department of Pathology & Immunology, Department of Molecular and Cellular Biology, Dan L. Duncan Cancer Center, Baylor College of Medicine, Houston, TX 77030, USA
| | - Kourosh Salehi-Ashtiani
- Laboratory of Algal, Systems, and Synthetic Biology, Division of Science and Math, and Center for Genomics and Systems Biology (CGSB), New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates.
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14
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Pinamonti G, Bottaro S, Micheletti C, Bussi G. Elastic network models for RNA: a comparative assessment with molecular dynamics and SHAPE experiments. Nucleic Acids Res 2015; 43:7260-9. [PMID: 26187990 PMCID: PMC4551938 DOI: 10.1093/nar/gkv708] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/30/2015] [Indexed: 11/23/2022] Open
Abstract
Elastic network models (ENMs) are valuable and efficient tools for characterizing the collective internal dynamics of proteins based on the knowledge of their native structures. The increasing evidence that the biological functionality of RNAs is often linked to their innate internal motions poses the question of whether ENM approaches can be successfully extended to this class of biomolecules. This issue is tackled here by considering various families of elastic networks of increasing complexity applied to a representative set of RNAs. The fluctuations predicted by the alternative ENMs are stringently validated by comparison against extensive molecular dynamics simulations and SHAPE experiments. We find that simulations and experimental data are systematically best reproduced by either an all-atom or a three-beads-per-nucleotide representation (sugar-base-phosphate), with the latter arguably providing the best balance of accuracy and computational complexity.
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Affiliation(s)
- Giovanni Pinamonti
- Scuola Internazionale Superiore di Studi Avanzati, International School for Advanced Studies, 265, Via Bonomea I-34136 Trieste, Italy
| | - Sandro Bottaro
- Scuola Internazionale Superiore di Studi Avanzati, International School for Advanced Studies, 265, Via Bonomea I-34136 Trieste, Italy
| | - Cristian Micheletti
- Scuola Internazionale Superiore di Studi Avanzati, International School for Advanced Studies, 265, Via Bonomea I-34136 Trieste, Italy
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati, International School for Advanced Studies, 265, Via Bonomea I-34136 Trieste, Italy
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