1
|
Riveros II, Yildirim I. Prediction of 3D RNA Structures from Sequence Using Energy Landscapes of RNA Dimers: Application to RNA Tetraloops. J Chem Theory Comput 2024; 20:4363-4376. [PMID: 38728627 DOI: 10.1021/acs.jctc.4c00189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Access to the three-dimensional structure of RNA enables an ability to gain a more profound understanding of its biological mechanisms, as well as the ability to design RNA-targeting drugs, which can take advantage of the unique chemical environment imposed by a folded RNA structure. Due to the dynamic and structurally complex properties of RNA, both experimental and traditional computational methods have difficulty in determining RNA's 3D structure. Herein, we introduce TAPERSS (Theoretical Analyses, Prediction, and Evaluation of RNA Structures from Sequence), a physics-based fragment assembly method for predicting 3D RNA structures from sequence. Using a fragment library created using discrete path sampling calculations of RNA dinucleoside monophosphates, TAPERSS can sample the physics-based energy landscapes of any RNA sequence with relatively low computational complexity. We have benchmarked TAPERSS on 21 RNA tetraloops, using a combinatorial algorithm as a proof-of-concept. We show that TAPERSS was successfully able to predict the apo-state structures of all 21 RNA hairpins, with 16 of those structures also having low predicted energies as well. We demonstrate that TAPERSS performs most accurately on GNRA-like tetraloops with mostly stacked loop-nucleotides, while having limited success with more dynamic UNCG and CUYG tetraloops, most likely due to the influence of the RNA force field used to create the fragment library. Moreover, we show that TAPERSS can successfully predict the majority of the experimental non-apo states, highlighting its potential in anticipating biologically significant yet unobserved states. This holds great promise for future applications in drug design and related studies. With discussed improvements and implementation of more efficient sampling algorithms, we believe TAPERSS may serve as a useful tool for a physics-based conformational sampling of large RNA structures.
Collapse
Affiliation(s)
- Ivan Isaac Riveros
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, Florida 33458, United States
| | - Ilyas Yildirim
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, Florida 33458, United States
| |
Collapse
|
2
|
Ma X, Zhang Y, Huang K, Zhu L, Xu W. Multifunctional rolling circle transcription-based nanomaterials for advanced drug delivery. Biomaterials 2023; 301:122241. [PMID: 37451000 DOI: 10.1016/j.biomaterials.2023.122241] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/21/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
As the up-and-comer in the development of RNA nanotechnology, RNA nanomaterials based on functionalized rolling circle transcription (RCT) have become promising carriers for drug production and delivery. This is due to RCT technology can self-produce polyvalent tandem nucleic acid prodrugs for intervention in intracellular gene expression and protein production. RNA component strands participating in de novo assembly enable RCT-based nanomaterials to exhibit good mechanical properties, biostability, and biocompatibility as delivery carriers. The biostability makes it to suitable for thermodynamically/kinetically favorable assembly, enzyme resistance and efficient expression in vivo. Controllable RCT system combined with polymers enables customizable and adjustable size, shape, structure, and stoichiometry of RNA building materials, which provide groundwork for the delivery of advanced drugs. Here, we review the assembly strategies and the dynamic regulation of RCT-based nanomaterials, summarize its functional properties referring to the bottom-up design philosophy, and describe its advancements in tumor gene therapy, synergistic chemotherapy, and immunotherapy. Last, we elaborate on the unique and practical value of RCT-based nanomaterials, namely "self-production and self-sale", and their potential challenges in nanotechnology, material science and biomedicine.
Collapse
Affiliation(s)
- Xuan Ma
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Yangzi Zhang
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Kunlun Huang
- College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Longjiao Zhu
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China
| | - Wentao Xu
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China.
| |
Collapse
|
3
|
Pokhrel P, Jonchhe S, Pan W, Mao H. Single-Molecular Dissection of Liquid-Liquid Phase Transitions. J Am Chem Soc 2023; 145:17143-17150. [PMID: 37494702 PMCID: PMC10528544 DOI: 10.1021/jacs.3c03812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
Interaction between peptides and nucleic acids is a ubiquitous process that drives many cellular functions, such as replications, transcriptions, and translations. Recently, this interaction has been found in liquid-liquid phase separation (LLPS), a process responsible for the formation of newly discovered membraneless organelles with a variety of biological functions inside cells. In this work, we studied the molecular interaction between the poly-l-lysine (PLL) peptide and nucleic acids during the early stage of an LLPS process at the single-molecule level using optical tweezers. By monitoring the mechanical tension of individual nucleic acid templates upon PLL addition, we revealed a multistage LLPS process mediated by the long-range interactions between nucleic acids and polyelectrolytes. By varying different types (ssDNA, ssRNA, and dsDNA) and sequences (A-, T-, G-, or U-rich) of nucleic acids, we pieced together transition diagrams of the PLL-nucleic acid condensates from which we concluded that the propensity to form rigid nucleic acid-PLL complexes reduces the condensate formation during the LLPS process. We anticipate that these results are instrumental in understanding the transition mechanism of LLPS condensates, which allows new strategies to interfere with the biological functions of LLPS condensates inside cells.
Collapse
Affiliation(s)
- Pravin Pokhrel
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Sagun Jonchhe
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Wei Pan
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| | - Hanbin Mao
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242, United States
| |
Collapse
|
4
|
Capobianco A, Landi A, Peluso A. Duplex DNA Retains the Conformational Features of Single Strands: Perspectives from MD Simulations and Quantum Chemical Computations. Int J Mol Sci 2022; 23:ijms232214452. [PMID: 36430930 PMCID: PMC9697240 DOI: 10.3390/ijms232214452] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 11/09/2022] [Accepted: 11/13/2022] [Indexed: 11/22/2022] Open
Abstract
Molecular dynamics simulations and geometry optimizations carried out at the quantum level as well as by quantum mechanical/molecular mechanics methods predict that short, single-stranded DNA oligonucleotides adopt conformations very similar to those observed in crystallographic double-stranded B-DNA, with rise coordinates close to ≈3.3 Å. In agreement with the experimental evidence, the computational results show that DNA single strands rich in adjacent purine nucleobases assume more regular arrangements than poly-thymine. The preliminary results suggest that single-stranded poly-cytosine DNA should also retain a substantial helical order in solution. A comparison of the structures of single and double helices confirms that the B-DNA motif is a favorable arrangement also for single strands. Indeed, the optimal geometry of the complementary single helices is changed to a very small extent in the formation of the duplex.
Collapse
|
5
|
Rizzuto FJ, Dore MD, Rafique MG, Luo X, Sleiman HF. DNA Sequence and Length Dictate the Assembly of Nucleic Acid Block Copolymers. J Am Chem Soc 2022; 144:12272-12279. [PMID: 35762655 DOI: 10.1021/jacs.2c03506] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The self-assembly of block copolymers is often rationalized by structure and microphase separation; pathways that diverge from this parameter space may provide new mechanisms of polymer assembly. Here, we show that the sequence and length of single-stranded DNA directly influence the self-assembly of sequence-defined DNA block copolymers. While increasing the length of DNA led to predictable changes in self-assembly, changing only the sequence of DNA produced three distinct structures: spherical micelles (spherical nucleic acids, SNAs) from flexible poly(thymine) DNA, fibers from semirigid mixed-sequence DNA, and networked superstructures from rigid poly(adenine) DNA. The secondary structure of poly(adenine) DNA strands drives a temperature-dependent polymerization and assembly mechanism: copolymers stored in an SNA reservoir form fibers after thermal activation, which then aggregate upon cooling to form interwoven networks. DNA is often used as a programming code that aids in nanostructure addressability and function. Here, we show that the inherent physical and chemical properties of single-stranded DNA sequences also make them an ideal material to direct self-assembled morphologies and select for new methods of supramolecular polymerization.
Collapse
Affiliation(s)
- Felix J Rizzuto
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC H3A 08B, Canada
| | - Michael D Dore
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC H3A 08B, Canada
| | | | - Xin Luo
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC H3A 08B, Canada
| | - Hanadi F Sleiman
- Department of Chemistry, McGill University, 801 Sherbrooke St W, Montréal, QC H3A 08B, Canada
| |
Collapse
|
6
|
González-Olvera JC, Zamorano-Carrillo A, Arreola-Jardón G, Pless RC. Residue interactions affecting the deprotonation of internal guanine moieties in oligodeoxyribonucleotides, calculated by FMO methods. J Mol Model 2022; 28:43. [DOI: 10.1007/s00894-022-05033-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 01/18/2022] [Indexed: 11/24/2022]
|
7
|
Zhao J, Kennedy SD, Turner DH. Nuclear Magnetic Resonance Spectra and AMBER OL3 and ROC-RNA Simulations of UCUCGU Reveal Force Field Strengths and Weaknesses for Single-Stranded RNA. J Chem Theory Comput 2022; 18:1241-1254. [PMID: 34990548 DOI: 10.1021/acs.jctc.1c00643] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Single-stranded regions of RNA are important for folding of sequences into 3D structures and for design of therapeutics targeting RNA. Prediction of ensembles of 3D structures for single-stranded regions often involves classical mechanical approximations of interactions defined by quantum mechanical calculations on small model systems. Nuclear magnetic resonance (NMR) spectra and molecular dynamics (MD) simulations of short single strands provide tests for how well the approximations model many of the interactions. Here, the NMR spectra for UCUCGU at 2, 15, and 30 °C are compared to simulations with the AMBER force fields, OL3 and ROC-RNA. This is the first such comparison to an oligoribonucleotide containing an internal guanosine nucleotide (G). G is particularly interesting because of its many H-bonding groups, large dipole moment, and proclivity for both syn and anti conformations. Results reveal formation of a G amino to phosphate non-bridging oxygen H-bond. The results also demonstrate dramatic differences in details of the predicted structures. The variations emphasize the dependence of predictions on individual parameters and their balance with the rest of the force field. The NMR data can serve as a benchmark for future force fields.
Collapse
|
8
|
Golyshev VM, Pyshnyi DV, Lomzov AA. Calculation of Energy for RNA/RNA and DNA/RNA Duplex Formation by Molecular Dynamics Simulation. Mol Biol 2021. [DOI: 10.1134/s002689332105006x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract
The development of approaches for predictive calculation of hybridization properties of various nucleic acid (NA) derivatives is the basis for the rational design of the NA-based constructs. Modern advances in computer modeling methods provide the feasibility of these calculations. We have analyzed the possibility of calculating the energy of DNA/RNA and RNA/RNA duplex formation using representative sets of complexes (65 and 75 complexes, respectively). We used the classical molecular dynamics (MD) method, the MMPBSA or MMGBSA approaches to calculate the enthalpy (ΔH°) component, and the quasi-harmonic approximation (Q-Harm) or the normal mode analysis (NMA) methods to calculate the entropy (ΔS°) contribution to the Gibbs energy ($$\Delta G_{{37}}^{^\circ }$$ ) of the NA complex formation. We have found that the MMGBSA method in the analysis of the MD trajectory of only the NA duplex and the empirical linear approximation allow calculation of the enthalpy of formation of the DNA, RNA, and hybrid duplexes of various lengths and GC content with an accuracy of 8.6%. Within each type of complex, the combination of rather efficient MMGBSA and Q-Harm approaches being applied to the trajectory of only the bimolecular complex makes it possible to calculate the $$\Delta G_{{37}}^{^\circ }$$ of the duplex formation with an error value of 10%. The high accuracy of predictive calculation for different types of natural complexes (DNA/RNA, DNA/RNA, and RNA/RNA) indicates the possibility of extending the considered approach to analogs and derivatives of nucleic acids, which gives a fundamental opportunity in the future to perform rational design of new types of NA-targeted sequence-specific compounds.
Collapse
|
9
|
Mukherjee I, Ghosh A, Purkayastha P. Förster Resonance Energy Transfer from Carbon Nanoparticles to a DNA-Bound Compound: A Method to Detect the Nature of Binding. J Phys Chem B 2021; 125:10126-10137. [PMID: 34465085 DOI: 10.1021/acs.jpcb.1c05149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A drug molecule can bind in various orientations to a DNA strand. Nature of the binding decides the functionality and efficacy of the drug. To innovate a new method to detect the nature of binding of a drug to DNA strands, herein we have used the dipole-dipole interaction driven Förster resonance energy transfer (FRET) between carbon nanoparticles (CNPs) and a DNA-bound small molecule, (E)-3-ethyl-2-(4-(pyrrolidin-1-yl)styryl)benzo[d]thiazol-3-ium (EPSBT), which belongs to the hemicyanine family and binds typically to the minor groove of a DNA duplex. EPSBT was designed to obtain appreciable fluorescence quantum yield, which constructed an efficient FRET pair with the synthesized CNPs. The tested compound prefers the thymine nucleobase to bind to the DNA strand. Orientation of its dipole on attachment to the DNA strand and the donor-acceptor distance dictate the FRET efficiency with the CNPs. The results provided a precise estimation of the nature of binding of EPSBT to the DNA backbone and, hence, supposedly will help in deciding the functional efficacy.
Collapse
Affiliation(s)
- Ishani Mukherjee
- Department of Chemical Sciences and Center for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, WB 741246, India
| | - Ashutosh Ghosh
- Department of Chemical Sciences and Center for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, WB 741246, India
| | - Pradipta Purkayastha
- Department of Chemical Sciences and Center for Advanced Functional Materials, Indian Institute of Science Education and Research (IISER) Kolkata, WB 741246, India
| |
Collapse
|
10
|
Chen Y, Khazina E, Izaurralde E, Weichenrieder O. Crystal structure and functional properties of the human CCR4-CAF1 deadenylase complex. Nucleic Acids Res 2021; 49:6489-6510. [PMID: 34038562 PMCID: PMC8216464 DOI: 10.1093/nar/gkab414] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 04/28/2021] [Accepted: 05/05/2021] [Indexed: 01/07/2023] Open
Abstract
The CCR4 and CAF1 deadenylases physically interact to form the CCR4-CAF1 complex and function as the catalytic core of the larger CCR4-NOT complex. Together, they are responsible for the eventual removal of the 3′-poly(A) tail from essentially all cellular mRNAs and consequently play a central role in the posttranscriptional regulation of gene expression. The individual properties of CCR4 and CAF1, however, and their respective contributions in different organisms and cellular environments are incompletely understood. Here, we determined the crystal structure of a human CCR4-CAF1 complex and characterized its enzymatic and substrate recognition properties. The structure reveals specific molecular details affecting RNA binding and hydrolysis, and confirms the CCR4 nuclease domain to be tethered flexibly with a considerable distance between both enzyme active sites. CCR4 and CAF1 sense nucleotide identity on both sides of the 3′-terminal phosphate, efficiently differentiating between single and consecutive non-A residues. In comparison to CCR4, CAF1 emerges as a surprisingly tunable enzyme, highly sensitive to pH, magnesium and zinc ions, and possibly allowing distinct reaction geometries. Our results support a picture of CAF1 as a primordial deadenylase, which gets assisted by CCR4 for better efficiency and by the assembled NOT proteins for selective mRNA targeting and regulation.
Collapse
Affiliation(s)
- Ying Chen
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Elena Khazina
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Elisa Izaurralde
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| | - Oliver Weichenrieder
- Department of Biochemistry, Max Planck Institute for Developmental Biology, Max-Planck-Ring 5, D-72076 Tübingen, Germany
| |
Collapse
|
11
|
Pérez‐Romero A, Domínguez‐Martín A, Galli S, Santamaría‐Díaz N, Palacios O, Dobado JA, Nyman M, Galindo MA. Single‐Stranded DNA as Supramolecular Template for One‐Dimensional Palladium(II) Arrays. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Antonio Pérez‐Romero
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - Alicia Domínguez‐Martín
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - Simona Galli
- 2 Dipartimento di Scienza e Alta Tecnologia Università dell'Insubria Via Valleggio 11 22100 Como Italy
| | - Noelia Santamaría‐Díaz
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - Oscar Palacios
- Departament de Química Facultat de Ciències Universitat Autònoma de Barcelona Campus Bellaterra s/n 08193 Cerdanyola del Vallès, Barcelona Spain
| | - José A. Dobado
- Grupo de Modelización y Diseño Molecular Departamento de Química Orgánica Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - May Nyman
- Department of Chemistry Oregon State University Corvallis OR 97331-4003 USA
| | - Miguel A. Galindo
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| |
Collapse
|
12
|
Broadwater DWB, Cook AW, Kim HD. First passage time study of DNA strand displacement. Biophys J 2021; 120:2400-2412. [PMID: 33894217 DOI: 10.1016/j.bpj.2021.01.043] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 12/18/2020] [Accepted: 01/12/2021] [Indexed: 12/15/2022] Open
Abstract
DNA strand displacement, in which a single-stranded nucleic acid invades a DNA duplex, is pervasive in genomic processes and DNA engineering applications. The kinetics of strand displacement have been studied in bulk; however, the kinetics of the underlying strand exchange were obfuscated by a slow bimolecular association step. Here, we use a novel single-molecule fluorescence resonance energy transfer approach termed the "fission" assay to obtain the full distribution of first passage times of unimolecular strand displacement. At a frame time of 4.4 ms, the first passage time distribution for a 14-nucleotide displacement domain exhibited a nearly monotonic decay with little delay. Among the eight different sequences we tested, the mean displacement time was on average 35 ms and varied by up to a factor of 13. The measured displacement kinetics also varied between complementary invaders and between RNA and DNA invaders of the same base sequence, except for T → U substitution. However, displacement times were largely insensitive to the monovalent salt concentration in the range of 0.25-1 M. Using a one-dimensional random walk model, we infer that the single-step displacement time is in the range of ∼30-300 μs, depending on the base identity. The framework presented here is broadly applicable to the kinetic analysis of multistep processes investigated at the single-molecule level.
Collapse
Affiliation(s)
- D W Bo Broadwater
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Alexander W Cook
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Harold D Kim
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia.
| |
Collapse
|
13
|
Pérez‐Romero A, Domínguez‐Martín A, Galli S, Santamaría‐Díaz N, Palacios O, Dobado JA, Nyman M, Galindo MA. Single‐Stranded DNA as Supramolecular Template for One‐Dimensional Palladium(II) Arrays. Angew Chem Int Ed Engl 2021; 60:10089-10094. [DOI: 10.1002/anie.202015554] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/15/2021] [Indexed: 12/27/2022]
Affiliation(s)
- Antonio Pérez‐Romero
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - Alicia Domínguez‐Martín
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - Simona Galli
- 2 Dipartimento di Scienza e Alta Tecnologia Università dell'Insubria Via Valleggio 11 22100 Como Italy
| | - Noelia Santamaría‐Díaz
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - Oscar Palacios
- Departament de Química Facultat de Ciències Universitat Autònoma de Barcelona Campus Bellaterra s/n 08193 Cerdanyola del Vallès, Barcelona Spain
| | - José A. Dobado
- Grupo de Modelización y Diseño Molecular Departamento de Química Orgánica Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| | - May Nyman
- Department of Chemistry Oregon State University Corvallis OR 97331-4003 USA
| | - Miguel A. Galindo
- Departamento de Química Inorgánica. Unidad de Excelencia de Química Aplicada a Biomedicina y, Medioambiente Universidad de Granada Avda Fuentenueva s/n 18071 Granada Spain
| |
Collapse
|
14
|
Plausible Minimal Substrate for Erm Protein. Antimicrob Agents Chemother 2020; 64:AAC.00023-20. [PMID: 32571809 PMCID: PMC7449152 DOI: 10.1128/aac.00023-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 06/13/2020] [Indexed: 11/20/2022] Open
Abstract
Erm proteins methylate a specific adenine residue (A2058, Escherichia coli coordinates) conferring macrolide-lincosamide-streptogramin B (MLSB) antibiotic resistance on a variety of microorganisms, ranging from antibiotic producers to pathogens. To identify the minimal motif required to be recognized and methylated by the Erm protein, various RNA substrates from 23S rRNA were constructed, and the substrate activity of these constructs was studied using three Erm proteins, namely, ErmB from Firmicutes and ErmE and ErmS from Actinobacteria. Erm proteins methylate a specific adenine residue (A2058, Escherichia coli coordinates) conferring macrolide-lincosamide-streptogramin B (MLSB) antibiotic resistance on a variety of microorganisms, ranging from antibiotic producers to pathogens. To identify the minimal motif required to be recognized and methylated by the Erm protein, various RNA substrates from 23S rRNA were constructed, and the substrate activity of these constructs was studied using three Erm proteins, namely, ErmB from Firmicutes and ErmE and ErmS from Actinobacteria. The shortest motif of 15 nucleotides (nt) could be recognized and methylated by ErmS, consisting of A2051 to the methylatable adenine (A2058) and its base-pairing counterpart strand, presumably assuming a quite similar structure to that in 23S rRNA, an unpaired target adenine immediately followed by an irregular double-stranded RNA region. This observation confirms the ultimate end of each side in helix 73 for methylation, determined by the approaches described above, and could reveal the mechanism behind the binding, recognition, induced fit, methylation, and conformational change for product release in the minimal context of substrate, presumably with the help of structural determination of the protein-RNA complex. In the course of determining the minimal portion of substrate from domain V, protein-specific features could be observed among the Erm proteins in terms of the methylation of RNA substrate and cooperativity and/or allostery between the region in helix 73 furthest away from the target adenine and the large portion of domain V above the methylatable adenine.
Collapse
|
15
|
Silva HVR, da Silva AM, Lee PC, Brito BF, Silva AR, da Silva LDM, Comizzoli P. Influence of Microwave-Assisted Drying on Structural Integrity and Viability of Testicular Tissues from Adult and Prepubertal Domestic Cats. Biopreserv Biobank 2020; 18:415-424. [PMID: 32780644 DOI: 10.1089/bio.2020.0048] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Anhydrous preservation is a promising approach for storage of living biomaterials at nonfreezing temperatures. Using the domestic cat model, the objectives of this study were to characterize changes in histology, DNA integrity, and viability of testicular tissues from adult versus prepubertal individuals during microwave-assisted drying. Testes from each age group were cut into small pieces before reversible membrane permeabilization, exposure to trehalose, and microwave-assisted drying during different time periods. In Experiment 1, water content was monitored for up to 40 minutes of drying. Tissues from adult or prepubertal cats experienced similar decreases of water content during the first 10 minutes. Desiccation progressed slowly between 10 and 20 minutes and then remained stable. In Experiment 2, structural properties were explored at 5, 10, and 20 minutes of desiccation. Percentages of normal seminiferous tubules were lower after 20 minutes drying in adult (43%) than in prepubertal tissues (61%). At the same time point, the proportion of cell degeneration was higher in adult (53%) than prepubertal tissues (28%). Percentages of intact DNA in tissues remained above 85% regardless of the microwave time in both age groups. Lastly, adult and prepubertal tissues only lost 33% of viability in both age groups. Collective results demonstrated for the first time that normal morphology, incidence of degeneration, DNA integrity, and viability of testicular tissues remained at acceptable levels during microwave-assisted drying for 20 minutes. Overall, prepubertal testicular tissues appeared to be more resilient to microwave-assisted desiccations than adult tissues. Importantly, water loss in the presence of trehalose after 20 minutes of desiccation already is compatible with long-term storage of testicular tissues at temperatures above -20°C, which is one step closer to future storage at supra-zero temperatures.
Collapse
Affiliation(s)
| | - Andréia Maria da Silva
- Laboratory of Animal Germplasm Conservation, Federal Rural University of Semi-Arid, Mossoró, Brazil
| | - Pei-Chih Lee
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
| | - Bruna Farias Brito
- Laboratory of Carnivores Reproduction, State University of Ceará, Fortaleza, Brazil
| | | | | | - Pierre Comizzoli
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, District of Columbia, USA
| |
Collapse
|
16
|
Bao C, Loerch S, Ling C, Korostelev AA, Grigorieff N, Ermolenko DN. mRNA stem-loops can pause the ribosome by hindering A-site tRNA binding. eLife 2020; 9:e55799. [PMID: 32427100 PMCID: PMC7282821 DOI: 10.7554/elife.55799] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/18/2020] [Indexed: 12/27/2022] Open
Abstract
Although the elongating ribosome is an efficient helicase, certain mRNA stem-loop structures are known to impede ribosome movement along mRNA and stimulate programmed ribosome frameshifting via mechanisms that are not well understood. Using biochemical and single-molecule Förster resonance energy transfer (smFRET) experiments, we studied how frameshift-inducing stem-loops from E. coli dnaX mRNA and the gag-pol transcript of Human Immunodeficiency Virus (HIV) perturb translation elongation. We find that upon encountering the ribosome, the stem-loops strongly inhibit A-site tRNA binding and ribosome intersubunit rotation that accompanies translation elongation. Electron cryo-microscopy (cryo-EM) reveals that the HIV stem-loop docks into the A site of the ribosome. Our results suggest that mRNA stem-loops can transiently escape the ribosome helicase by binding to the A site. Thus, the stem-loops can modulate gene expression by sterically hindering tRNA binding and inhibiting translation elongation.
Collapse
Affiliation(s)
- Chen Bao
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| | - Sarah Loerch
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
| | - Clarence Ling
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| | - Andrei A Korostelev
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical SchoolWorcesterUnited States
- RNA Therapeutics Institute, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Nikolaus Grigorieff
- Janelia Research Campus, Howard Hughes Medical InstituteAshburnUnited States
- RNA Therapeutics Institute, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Dmitri N Ermolenko
- Department of Biochemistry and Biophysics at School of Medicine and Dentistry and Center for RNA Biology, University of RochesterRochesterUnited States
| |
Collapse
|
17
|
Stellwagen E, Stellwagen NC. Electrophoretic Mobility of DNA in Solutions of High Ionic Strength. Biophys J 2020; 118:2783-2789. [PMID: 32445623 DOI: 10.1016/j.bpj.2020.02.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/06/2020] [Accepted: 02/27/2020] [Indexed: 12/11/2022] Open
Abstract
The free-solution mobilities of small single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA) have been measured by capillary electrophoresis in solutions containing 0.01-1.0 M sodium acetate. The mobility of dsDNA is greater than that of ssDNA at all ionic strengths because of the greater charge density of dsDNA. The mobilities of both ssDNA and dsDNA decrease with increasing ionic strength until approaching plateau values at ionic strengths greater than ∼0.6 M. Hence, ssDNA and dsDNA appear to interact in a similar manner with the ions in the background electrolyte. For dsDNA, the mobilities predicted by the Manning electrophoresis equation are reasonably close to the observed mobilities, using no adjustable parameters, if the average distance between phosphate residues (the b parameter) is taken to be 1.7 Å. For ssDNA, the predicted mobilities are close to the observed mobilities at ionic strengths ≤0.01 M if the b-value is taken to be 4.1 Å. The predicted and observed mobilities diverge strongly at higher ionic strengths unless the b-value is reduced significantly. The results suggest that ssDNA strands exist as an ensemble of relatively compact conformations at high ionic strengths, with b-values corresponding to the relatively short phosphate-phosphate distances through space.
Collapse
|
18
|
Tang TTL, Passmore LA. Recognition of Poly(A) RNA through Its Intrinsic Helical Structure. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2020; 84:21-30. [PMID: 32295929 PMCID: PMC7116106 DOI: 10.1101/sqb.2019.84.039818] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The polyadenosine (poly(A)) tail, which is found on the 3’ end of almost all eukaryotic messenger RNAs (mRNAs), plays an important role in the posttranscriptional regulation of gene expression. Shortening of the poly(A) tail, a process known as deadenylation, is thought to be the first and rate-limiting step of mRNA turnover. Deadenylation is performed by the Pan2–Pan3 and Ccr4–Not complexes that contain highly conserved exonuclease enzymes Pan2, and Ccr4 and Caf1, respectively. These complexes have been extensively studied, but the mechanisms of how the deadenylase enzymes recognize the poly(A) tail were poorly understood until recently. Here, we summarize recent work from our laboratory demonstrating that the highly conserved Pan2 exonuclease recognizes the poly(A) tail, not through adenine-specific functional groups, but through the conformation of poly(A) RNA. Our biochemical, biophysical, and structural investigations suggest that poly(A) forms an intrinsic base-stacked, single-stranded helical conformation that is recognized by Pan2, and that disruption of this structure inhibits both Pan2 and Caf1. This intrinsic structure has been shown to be important in poly(A) recognition in other biological processes, further underlining the importance of the unique conformation of poly(A).
Collapse
Affiliation(s)
- Terence T L Tang
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Lori A Passmore
- MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| |
Collapse
|
19
|
Baez WD, Roy B, McNutt ZA, Shatoff EA, Chen S, Bundschuh R, Fredrick K. Global analysis of protein synthesis in Flavobacterium johnsoniae reveals the use of Kozak-like sequences in diverse bacteria. Nucleic Acids Res 2019; 47:10477-10488. [PMID: 31602466 PMCID: PMC6847099 DOI: 10.1093/nar/gkz855] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/16/2019] [Accepted: 09/30/2019] [Indexed: 12/31/2022] Open
Abstract
In all cells, initiation of translation is tuned by intrinsic features of the mRNA. Here, we analyze translation in Flavobacterium johnsoniae, a representative of the Bacteroidetes. Members of this phylum naturally lack Shine-Dalgarno (SD) sequences in their mRNA, and yet their ribosomes retain the conserved anti-SD sequence. Translation initiation is tuned by mRNA secondary structure and by the identities of several key nucleotides upstream of the start codon. Positive determinants include adenine at position -3, reminiscent of the Kozak sequence of Eukarya. Comparative analysis of Escherichia coli reveals use of the same Kozak-like sequence to enhance initiation, suggesting an ancient and widespread mechanism. Elimination of contacts between A-3 and the conserved β-hairpin of ribosomal protein uS7 fails to diminish the contribution of A-3 to initiation, suggesting an indirect mode of recognition. Also, we find that, in the Bacteroidetes, the trinucleotide AUG is underrepresented in the vicinity of the start codon, which presumably helps compensate for the absence of SD sequences in these organisms.
Collapse
Affiliation(s)
- William D Baez
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Bappaditya Roy
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Zakkary A McNutt
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elan A Shatoff
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Shicheng Chen
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Ralf Bundschuh
- Department of Physics, The Ohio State University, Columbus, OH 43210, USA
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Chemistry and Biochemistry, Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
20
|
The Dynamics of Hole Transfer in DNA. Molecules 2019; 24:molecules24224044. [PMID: 31703470 PMCID: PMC6891780 DOI: 10.3390/molecules24224044] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 10/31/2019] [Accepted: 11/02/2019] [Indexed: 11/21/2022] Open
Abstract
High-energy radiation and oxidizing agents can ionize DNA. One electron oxidation gives rise to a radical cation whose charge (hole) can migrate through DNA covering several hundreds of Å, eventually leading to irreversible oxidative damage and consequent disease. Understanding the thermodynamic, kinetic and chemical aspects of the hole transport in DNA is important not only for its biological consequences, but also for assessing the properties of DNA in redox sensing or labeling. Furthermore, due to hole migration, DNA could potentially play an important role in nanoelectronics, by acting as both a template and active component. Herein, we review our work on the dynamics of hole transfer in DNA carried out in the last decade. After retrieving the thermodynamic parameters needed to address the dynamics of hole transfer by voltammetric and spectroscopic experiments and quantum chemical computations, we develop a theoretical methodology which allows for a faithful interpretation of the kinetics of the hole transport in DNA and is also capable of taking into account sequence-specific effects.
Collapse
|
21
|
Tang TTL, Stowell JAW, Hill CH, Passmore LA. The intrinsic structure of poly(A) RNA determines the specificity of Pan2 and Caf1 deadenylases. Nat Struct Mol Biol 2019; 26:433-442. [PMID: 31110294 PMCID: PMC6555765 DOI: 10.1038/s41594-019-0227-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/11/2019] [Indexed: 11/09/2022]
Abstract
The 3' poly(A) tail of messenger RNA is fundamental to regulating eukaryotic gene expression. Shortening of the poly(A) tail, termed deadenylation, reduces transcript stability and inhibits translation. Nonetheless, the mechanism for poly(A) recognition by the conserved deadenylase complexes Pan2-Pan3 and Ccr4-Not is poorly understood. Here we provide a model for poly(A) RNA recognition by two DEDD-family deadenylase enzymes, Pan2 and the Ccr4-Not nuclease Caf1. Crystal structures of Saccharomyces cerevisiae Pan2 in complex with RNA show that, surprisingly, Pan2 does not form canonical base-specific contacts. Instead, it recognizes the intrinsic stacked, helical conformation of poly(A) RNA. Using a fully reconstituted biochemical system, we show that disruption of this structure-for example, by incorporation of guanosine into poly(A)-inhibits deadenylation by both Pan2 and Caf1. Together, these data establish a paradigm for specific recognition of the conformation of poly(A) RNA by proteins that regulate gene expression.
Collapse
Affiliation(s)
| | | | - Chris H Hill
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | |
Collapse
|
22
|
Han X, Wang E, Cui Y, Lin Y, Chen H, An R, Liang X, Komiyama M. The staining efficiency of cyanine dyes for single-stranded DNA is enormously dependent on nucleotide composition. Electrophoresis 2019; 40:1708-1714. [PMID: 31004446 DOI: 10.1002/elps.201800445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/21/2019] [Accepted: 04/15/2019] [Indexed: 11/12/2022]
Abstract
The staining of nucleic acids with fluorescent dyes is one of the most fundamental technologies in relevant areas of science. For reliable and quantitative analysis, the staining efficiency of the dyes should not be very dependent on the sequences of the specimens. However, this assumption has not necessarily been confirmed by experimental results, especially in the staining of ssDNA (and RNA). In this study, we found that both SYBR Green II and SYBR Gold did not stain either homopyrimidines or ssDNA composed of only adenine (A) and cytosine (C). However, these two dyes emit strong fluorescence when the ssDNA contains both guanine (G) and C (and/or both A and thymine (T)) and form potential Watson-Crick base pairs. Interestingly, SYBR Gold, but not SYBR Green II, strongly stains ssDNA consisting of G and A (or G and T). Additionally, we found that the secondary structure of ssDNA may play an important role in DNA staining. To obtain reliable results for practical applications, sufficient care must be paid to the composition and sequence of ssDNA.
Collapse
Affiliation(s)
- Xutiange Han
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Erchi Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Yixiao Cui
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Yikai Lin
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Hui Chen
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| | - Ran An
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, P. R. China
| | - Xingguo Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China.,Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao, P. R. China
| | - Makoto Komiyama
- College of Food Science and Engineering, Ocean University of China, Qingdao, P. R. China
| |
Collapse
|
23
|
Pal A, Levy Y. Structure, stability and specificity of the binding of ssDNA and ssRNA with proteins. PLoS Comput Biol 2019; 15:e1006768. [PMID: 30933978 PMCID: PMC6467422 DOI: 10.1371/journal.pcbi.1006768] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 04/16/2019] [Accepted: 01/01/2019] [Indexed: 02/06/2023] Open
Abstract
Recognition of single-stranded DNA (ssDNA) or single-stranded RNA (ssRNA) is important for many fundamental cellular functions. A variety of single-stranded DNA-binding proteins (ssDBPs) and single-stranded RNA-binding proteins (ssRBPs) have evolved that bind ssDNA and ssRNA, respectively, with varying degree of affinities and specificities to form complexes. Structural studies of these complexes provide key insights into their recognition mechanism. However, computational modeling of the specific recognition process and to predict the structure of the complex is challenging, primarily due to the heterogeneity of their binding energy landscape and the greater flexibility of ssDNA or ssRNA compared with double-stranded nucleic acids. Consequently, considerably fewer computational studies have explored interactions between proteins and single-stranded nucleic acids compared with protein interactions with double-stranded nucleic acids. Here, we report a newly developed energy-based coarse-grained model to predict the structure of ssDNA–ssDBP and ssRNA–ssRBP complexes and to assess their sequence-specific interactions and stabilities. We tuned two factors that can modulate specific recognition: base–aromatic stacking strength and the flexibility of the single-stranded nucleic acid. The model was successfully applied to predict the binding conformations of 12 distinct ssDBP and ssRBP structures with their cognate ssDNA and ssRNA partners having various sequences. Estimated binding energies agreed well with the corresponding experimental binding affinities. Bound conformations from the simulation showed a funnel-shaped binding energy distribution where the native-like conformations corresponded to the energy minima. The various ssDNA–protein and ssRNA–protein complexes differed in the balance of electrostatic and aromatic energies. The lower affinity of the ssRNA–ssRBP complexes compared with the ssDNA–ssDBP complexes stems from lower flexibility of ssRNA compared to ssDNA, which results in higher rate constants for the dissociation of the complex (koff) for complexes involving the former. Quantifying bimolecular self-assembly is pivotal to understanding cellular function. In recent years, a large progress has been made in understanding the structure and biophysics of protein-protein interactions. Particularly, various computational tools are available for predicting these structures and to estimate their stability and the driving forces of their formation. The understating of the interactions between proteins and nucleic acids, however, is still limited, presumably due to the involvement of non-specific interactions as well as the high conformational plasticity that may demand an induced-fit mechanism. In particular, the interactions between proteins and single-stranded nucleic acids (i.e., single-stranded DNA and RNA) is very challenging due to their high flexibility. Furthermore, the interface between proteins and single-stranded nucleic acids is often chemically more heterogeneous than the interface between proteins and double-stranded DNA. In this study, we developed a coarse-grained computational model to predict the structure of complexes between proteins and single-stranded nucleic acids. The model was applied to estimate binding affinities and the estimated binding energies agreed well with the corresponding experimental binding affinities. The kinetics of association as well as the specificity of the complexes between proteins and ssDNA are different than those with ssRNA, mostly due to differences in their conformational flexibility.
Collapse
Affiliation(s)
- Arumay Pal
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Yaakov Levy
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
- * E-mail:
| |
Collapse
|
24
|
Abstract
Our current knowledge on the unique roles of RNA in cells makes it vital to investigate the properties of RNA systems using computational methods because of the potential pharmaceutical applications. With the continuous advancement of computer technology, it is now possible to study RNA folding. Molecular mechanics calculations are useful in discovering the structural and thermodynamic properties of RNA systems. Yet, the predictions depend on the quality of the RNA force field, which is a set of parameters describing the potential energy of the system. Torsional parameters are one of the terms in a force field that can be revised using physics-based approaches. This chapter focuses on improvements provided by revisions of torsional parameters of the AMBER (Assisted Model Building with Energy Refinement) RNA force field. The theory behind torsional revisions and re-parameterization of several RNA torsions is briefly described. Applications of the revised torsional parameters to study RNA nucleosides, single-stranded RNA tetramers, and RNA repeat expansions are described in detail. It is concluded that RNA force fields require constant revisions and should be benchmarked against diverse RNA systems such as single strands and internal loops in order to test their qualities.
Collapse
|
25
|
Grotz KK, Nueesch MF, Holmstrom ED, Heinz M, Stelzl LS, Schuler B, Hummer G. Dispersion Correction Alleviates Dye Stacking of Single-Stranded DNA and RNA in Simulations of Single-Molecule Fluorescence Experiments. J Phys Chem B 2018; 122:11626-11639. [PMID: 30285443 DOI: 10.1021/acs.jpcb.8b07537] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We combine single-molecule Förster resonance energy transfer (single-molecule FRET) experiments with extensive all-atom molecular dynamics (MD) simulations (>100 μs) to characterize the conformational ensembles of single-stranded (ss) DNA and RNA in solution. From MD simulations with explicit dyes attached to single-stranded nucleic acids via flexible linkers, we calculate FRET efficiencies and fluorescence anisotropy decays. We find that dispersion-corrected water models alleviate the problem of overly abundant interactions between fluorescent dyes and the aromatic ring systems of nucleobases. To model dye motions in a computationally efficient and conformationally exhaustive manner, we introduce a dye-conformer library, built from simulations of dinucleotides with covalently attached dye molecules. We use this library to calculate FRET efficiencies for dT19, dA19, and rA19 simulated without explicit labels over a wide range of salt concentrations. For end-labeled homopolymeric pyrimidine ssDNA, MD simulations with the parmBSC1 force field capture the overall trend in salt-dependence of single-molecule FRET based distance measurements. For homopolymeric purine ssRNA and ssDNA, the DESRES and parmBSC1 force fields, respectively, provide useful starting points, even though our comparison also identifies clear deviations from experiment.
Collapse
Affiliation(s)
- Kara K Grotz
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , 60438 Frankfurt am Main , Germany
| | - Mark F Nueesch
- Department of Biochemistry , University of Zurich , 8057 Zurich , Switzerland
| | - Erik D Holmstrom
- Department of Biochemistry , University of Zurich , 8057 Zurich , Switzerland
| | - Marcel Heinz
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , 60438 Frankfurt am Main , Germany
| | - Lukas S Stelzl
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , 60438 Frankfurt am Main , Germany
| | - Benjamin Schuler
- Department of Biochemistry , University of Zurich , 8057 Zurich , Switzerland.,Department of Physics , University of Zurich , 8057 Zurich , Switzerland
| | - Gerhard Hummer
- Department of Theoretical Biophysics , Max Planck Institute of Biophysics , 60438 Frankfurt am Main , Germany.,Institute of Biophysics , Goethe University Frankfurt , 60438 Frankfurt am Main , Germany
| |
Collapse
|
26
|
Capobianco A, Velardo A, Peluso A. Single-Stranded DNA Oligonucleotides Retain Rise Coordinates Characteristic of Double Helices. J Phys Chem B 2018; 122:7978-7989. [PMID: 30070843 DOI: 10.1021/acs.jpcb.8b04542] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The structures of single-stranded DNA oligonucleotides from dimeric to hexameric sequences have been thoroughly investigated. Computations performed at the density functional level of theory including dispersion forces and solvation show that single-stranded helices adopt conformations very close to crystallographic B-DNA, with rise coordinates amounting up to 3.3 Å. Previous results, suggesting that single strands should be shorter than double helices, largely originated from the incompleteness of the adopted basis set. Although sensible deviations with respect to standard B-DNA are predicted, computations indicate that sequences rich in stacked adenines are the most ordered ones, favoring the B-DNA pattern and inducing regular arrangements also on flanking nucleobases. Several structural properties of double helices rich in adenine are indeed already reflected by the corresponding single strands.
Collapse
Affiliation(s)
- Amedeo Capobianco
- Dipartimento di Chimica e Biologia "A. Zambelli" , Università di Salerno , Via Giovanni Paolo II , I-84084 Fisciano (SA) , Italy
| | - Amalia Velardo
- Dipartimento di Chimica e Biologia "A. Zambelli" , Università di Salerno , Via Giovanni Paolo II , I-84084 Fisciano (SA) , Italy
| | - Andrea Peluso
- Dipartimento di Chimica e Biologia "A. Zambelli" , Università di Salerno , Via Giovanni Paolo II , I-84084 Fisciano (SA) , Italy
| |
Collapse
|
27
|
Chakraborty D, Hori N, Thirumalai D. Sequence-Dependent Three Interaction Site Model for Single- and Double-Stranded DNA. J Chem Theory Comput 2018; 14:3763-3779. [PMID: 29870236 PMCID: PMC6423546 DOI: 10.1021/acs.jctc.8b00091] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We develop a robust coarse-grained model for single- and double-stranded DNA by representing each nucleotide by three interaction sites (TIS) located at the centers of mass of sugar, phosphate, and base. The resulting TIS model includes base-stacking, hydrogen bond, and electrostatic interactions as well as bond-stretching and bond angle potentials that account for the polymeric nature of DNA. The choices of force constants for stretching and the bending potentials were guided by a Boltzmann inversion procedure using a large representative set of DNA structures extracted from the Protein Data Bank. Some of the parameters in the stacking interactions were calculated using a learning procedure, which ensured that the experimentally measured melting temperatures of dimers are faithfully reproduced. Without any further adjustments, the calculations based on the TIS model reproduce the experimentally measured salt and sequence-dependence of the size of single-stranded DNA (ssDNA), as well as the persistence lengths of poly(dA) and poly(dT) chains. Interestingly, upon application of mechanical force, the extension of poly(dA) exhibits a plateau, which we trace to the formation of stacked helical domains. In contrast, the force-extension curve (FEC) of poly(dT) is entropic in origin and could be described by a standard polymer model. We also show that the persistence length of double-stranded DNA, formed from two complementary ssDNAs, is consistent with the prediction based on the worm-like chain. The persistence length, which decreases with increasing salt concentration, is in accord with the Odijk-Skolnick-Fixman theory intended for stiff polyelectrolyte chains near the rod limit. Our model predicts the melting temperatures of DNA hairpins with excellent accuracy, and we are able to recover the experimentally known sequence-specific trends. The range of applications, which did not require adjusting any parameter after the initial construction based solely on PDB structures and melting profiles of dimers, attests to the transferability and robustness of the TIS model for ssDNA and dsDNA.
Collapse
Affiliation(s)
- Debayan Chakraborty
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Naoto Hori
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - D. Thirumalai
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| |
Collapse
|
28
|
Frith KA, Fogel R, Goldring JPD, Krause RGE, Khati M, Hoppe H, Cromhout ME, Jiwaji M, Limson JL. Towards development of aptamers that specifically bind to lactate dehydrogenase of Plasmodium falciparum through epitopic targeting. Malar J 2018; 17:191. [PMID: 29724225 PMCID: PMC5934816 DOI: 10.1186/s12936-018-2336-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 04/26/2018] [Indexed: 11/19/2022] Open
Abstract
Background Early detection is crucial for the effective treatment of malaria, particularly in those cases infected with Plasmodium falciparum. There is a need for diagnostic devices with the capacity to distinguish P. falciparum from other strains of malaria. Here, aptamers generated against targeted species-specific epitopes of P. falciparum lactate dehydrogenase (rPfLDH) are described. Results Two classes of aptamers bearing high binding affinity and specificity for recombinant P. falciparum lactate dehydrogenase (rPfLDH) and P. falciparum-specific lactate dehydrogenase epitopic oligopeptide (LDHp) were separately generated. Structurally-relevant moieties with particular consensus sequences (GGTAG and GGCG) were found in aptamers reported here and previously published, confirming their importance in recognition of the target, while novel moieties particular to this work (ATTAT and poly-A stretches) were identified. Aptamers with diagnostically-supportive functions were synthesized, prime examples of which are the aptamers designated as LDHp 1, LDHp 11 and rLDH 4 and rLDH 15 in work presented herein. Of the sampled aptamers raised against the recombinant protein, rLDH 4 showed the highest binding to the target rPfLDH in the ELONA assay, with both rLDH 4 and rLDH 15 indicating an ability to discriminate between rPfLDH and rPvLDH. LDHp 11 was generated against a peptide selected as a unique P. falciparum LDH peptide. The aptamer, LDHp 11, like antibodies against the same peptide, only detected rPfLDH and discriminated between rPfLDH and rPvLDH. This was supported by affinity binding experiments where only aptamers generated against a unique species-specific epitope showed an ability to preferentially bind to rPfLDH relative to rPvLDH rather than those generated against the whole recombinant protein. In addition, rLDH 4 and LDHp 11 demonstrated in situ binding to P. falciparum cells during confocal microscopy. Conclusions The utilization and application of LDHp 11, an aptamer generated against a unique species-specific epitope of P. falciparum LDH indicated the ability to discriminate between recombinant P. falciparum and Plasmodium vivax LDH. This aptamer holds promise as a biorecognition element in malaria diagnostic devices for the detection, and differentiation, of P. falciparum and P. vivax malaria infections. This study paves the way to explore aptamer generation against targeted species-specific epitopes of other Plasmodium species.
Collapse
Affiliation(s)
- Kelly-Anne Frith
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown, 6140, Eastern Cape, South Africa
| | - Ronen Fogel
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown, 6140, Eastern Cape, South Africa
| | - J P Dean Goldring
- Department of Biochemistry, Genetics and Microbiology, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, KwaZulu-Natal, South Africa
| | - Robert G E Krause
- Department of Biochemistry, Genetics and Microbiology, University of KwaZulu-Natal, Private Bag X01, Scottsville, 3209, KwaZulu-Natal, South Africa
| | - Makobetsa Khati
- Emerging Health Technologies Platform, Biosciences Division, Council for Scientific and Industrial Research, PO Box 395, Pretoria, 0001, Gauteng, South Africa
| | - Heinrich Hoppe
- Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown, 6140, Eastern Cape, South Africa
| | - Mary E Cromhout
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown, 6140, Eastern Cape, South Africa
| | - Meesbah Jiwaji
- Department of Biochemistry and Microbiology, Rhodes University, P.O. Box 94, Grahamstown, 6140, Eastern Cape, South Africa
| | - Janice L Limson
- Biotechnology Innovation Centre, Rhodes University, P.O. Box 94, Grahamstown, 6140, Eastern Cape, South Africa.
| |
Collapse
|
29
|
Plashkevych O, Li Q, Chattopadhyaya J. How RNase HI (Escherichia coli) promoted site-selective hydrolysis works on RNA in duplex with carba-LNA and LNA substituted antisense strands in an antisense strategy context? MOLECULAR BIOSYSTEMS 2018; 13:921-938. [PMID: 28352859 DOI: 10.1039/c6mb00762g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A detailed kinetic study of 36 single modified AON-RNA heteroduplexes shows that substitution of a single native nucleotide in the antisense strand (AON) by locked nucleic acid (LNA) or by diastereomerically pure carba-LNA results in site-dependent modulation of RNase H promoted cleavage of complementary mRNA strands by 2 to 5 fold at 5'-GpN-3' cleavage sites, giving up to 70% of the RNA cleavage products. The experiments have been performed using RNase HI of Escherichia coli. The 2nd best cleavage site, being the 5'-ApN-3' sites, cleaves up to 23%, depending upon the substitution site in 36 isosequential complementary AONs. A comparison of the modified AON promoted RNA cleavage rates with that of the native AON shows that sequence-specificity is considerably enhanced as a result of modification. Clearly, relatively weaker 5'-purine (Pu)-pyrimidine (Py)-3' stacking in the complementary RNA strand is preferred (giving ∼90% of total cleavage products), which plays an important role in RNase H promoted RNA cleavage. A plausible mechanism of RNase H mediated cleavage of the RNA has been proposed to be two-fold, dictated by the balancing effect of the aromatic character of the purine aglycone: first, the locally formed 9-guanylate ion (pKa 9.3, ∼18-20% N1 ionized at pH 8) alters the adjoining sugar-phosphate backbone around the scissile phosphate, transforming its sugar N/S conformational equilibrium, to preferential S-type, causing preferential cleavage at 5'-GpN-3' sites around the center of 20 mer complementary mRNA. Second, the weaker nearest-neighbor strength of 5'-Pu-p-Py-3' stacking promotes preferential 5'-GpN-3' and 5'-ApN-3' cleavage, providing ∼90% of the total products, compared to ∼50% in that of the native one, because of the cLNA/LNA substituent effect on the neighboring 5'-Pu-p-Py-3' sites, providing both local steric flexibility and additional hydration. This facilitates both the water and water/Mg2+ ion availability at the cleavage site causing sequence-specific hydrolysis of the phosphodiester bond of scissile phosphate. The enhancement of the total rate of cleavage of the complementary mRNA strand by up to 25%, presented in this work, provides opportunities to engineer a single modification site in appropriately substituted AONs to design an effective antisense strategy based on the nucleolytic stability of the AON strand versus RNase H capability to cleave the complementary RNA strand.
Collapse
Affiliation(s)
- Oleksandr Plashkevych
- Chemical Biology Program, Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 581, SE-751 23 Uppsala, Sweden.
| | | | | |
Collapse
|
30
|
Plumridge A, Meisburger SP, Pollack L. Visualizing single-stranded nucleic acids in solution. Nucleic Acids Res 2017; 45:e66. [PMID: 28034955 PMCID: PMC5435967 DOI: 10.1093/nar/gkw1297] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/09/2016] [Accepted: 12/13/2016] [Indexed: 02/06/2023] Open
Abstract
Single-stranded nucleic acids (ssNAs) are ubiquitous in many key cellular functions. Their flexibility limits both the number of high-resolution structures available, leaving only a small number of protein-ssNA crystal structures, while forcing solution investigations to report ensemble averages. A description of the conformational distributions of ssNAs is essential to more fully characterize biologically relevant interactions. We combine small angle X-ray scattering (SAXS) with ensemble-optimization methods (EOM) to dynamically build and refine sets of ssNA structures. By constructing candidate chains in representative dinucleotide steps and refining the models against SAXS data, a broad array of structures can be obtained to match varying solution conditions and strand sequences. In addition to the distribution of large scale structural parameters, this approach reveals, for the first time, intricate details of the phosphate backbone and underlying strand conformations. Such information on unperturbed strands will critically inform a detailed understanding of an array of problems including protein-ssNA binding, RNA folding and the polymer nature of NAs. In addition, this scheme, which couples EOM selection with an iteratively refining pool to give confidence in the underlying structures, is likely extendable to the study of other flexible systems.
Collapse
Affiliation(s)
- Alex Plumridge
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| | | | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
31
|
Pieńko T, Wierzba AJ, Wojciechowska M, Gryko D, Trylska J. Conformational Dynamics of Cyanocobalamin and Its Conjugates with Peptide Nucleic Acids. J Phys Chem B 2017; 121:2968-2979. [PMID: 28301169 DOI: 10.1021/acs.jpcb.7b00649] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vitamin B12 also called cobalamin (Cbl) is an important enzymatic cofactor taken up by mammalian and also by many bacterial cells. Peptide nucleic acid (PNA) is a synthetic DNA analogue that has the ability to bind in a complementary manner to natural nucleic acids. Provided that PNA is efficiently delivered to cells, it could act as a steric blocker of functional DNA or RNA and regulate gene expression at the level of transcription or translation. Recently, Cbl has been examined as a transporter of various molecules to cells. Also, PNA, if covalently linked with Cbl, can be delivered to bacterial cells, but it is crucial to verify that Cbl does not change the desired PNA biological properties. We have analyzed the structure and conformational dynamics of conjugates of Cbl with a PNA monomer and oligomer. We synthesized a cyanocobalamin derivative with a PNA monomer C connected via the triazole linker and determined its NMR spectra. Using microsecond-long molecular dynamics simulations, we examined the internal dynamics of cyanocobalamin-C, its conjugate with a 14-mer PNA, and free PNA. The results suggest that all compounds acquire rather compact structures but the PNA oligomer conformations vary. For the Cbl-C conjugate the cross-peaks from the ROESY spectrum corroborated with the clusters from molecular dynamics trajectories. Within PNA the dominant interaction is stacking but the stacking bases are not necessarily neighboring in the PNA sequence. More bases stack in free PNA than in PNA of the conjugate, but stacking is less stable in free PNA. PNA in the conjugate is slightly more exposed to solvent. Overall, cyanocobalamin attached to a PNA oligomer increases the flexibility of PNA in a way that could be beneficial for its hybridization with natural nucleic acid oligomers.
Collapse
Affiliation(s)
- Tomasz Pieńko
- Centre of New Technologies, University of Warsaw , S. Banacha 2c, 02-097 Warsaw, Poland.,Department of Drug Chemistry, Faculty of Pharmacy with the Laboratory Medicine Division, Medical University of Warsaw , S. Banacha 1a, 02-097 Warsaw, Poland
| | - Aleksandra J Wierzba
- Institute of Organic Chemistry, Polish Academy of Sciences , M. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Monika Wojciechowska
- Centre of New Technologies, University of Warsaw , S. Banacha 2c, 02-097 Warsaw, Poland
| | - Dorota Gryko
- Institute of Organic Chemistry, Polish Academy of Sciences , M. Kasprzaka 44/52, 01-224 Warsaw, Poland
| | - Joanna Trylska
- Centre of New Technologies, University of Warsaw , S. Banacha 2c, 02-097 Warsaw, Poland
| |
Collapse
|
32
|
Gavette JV, Stoop M, Hud NV, Krishnamurthy R. RNA-DNA Chimeras in the Context of an RNA World Transition to an RNA/DNA World. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607919] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jesse V. Gavette
- Department of Chemistry; The Scripps Research Institute; 10550 N. Torrey Pines Rd. La Jolla CA 92037 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| | - Matthias Stoop
- Department of Chemistry; The Scripps Research Institute; 10550 N. Torrey Pines Rd. La Jolla CA 92037 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| | - Nicholas V. Hud
- School of Chemistry and Biochemistry; Georgia Institute of Technology; Atlanta GA 30332 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| | - Ramanarayanan Krishnamurthy
- Department of Chemistry; The Scripps Research Institute; 10550 N. Torrey Pines Rd. La Jolla CA 92037 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| |
Collapse
|
33
|
Gavette JV, Stoop M, Hud NV, Krishnamurthy R. RNA-DNA Chimeras in the Context of an RNA World Transition to an RNA/DNA World. Angew Chem Int Ed Engl 2016; 55:13204-13209. [DOI: 10.1002/anie.201607919] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Jesse V. Gavette
- Department of Chemistry; The Scripps Research Institute; 10550 N. Torrey Pines Rd. La Jolla CA 92037 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| | - Matthias Stoop
- Department of Chemistry; The Scripps Research Institute; 10550 N. Torrey Pines Rd. La Jolla CA 92037 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| | - Nicholas V. Hud
- School of Chemistry and Biochemistry; Georgia Institute of Technology; Atlanta GA 30332 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| | - Ramanarayanan Krishnamurthy
- Department of Chemistry; The Scripps Research Institute; 10550 N. Torrey Pines Rd. La Jolla CA 92037 USA
- NSF-NASA Center for Chemical Evolution; Atlanta GA 30332 USA
| |
Collapse
|
34
|
Kim J, Sambalkhundev GO, Kim S, Son J, Han AR, Ko SM, Hwang KY, Lee WC. Processing of A-form ssDNA by cryptic RNase H fold exonuclease PF2046. Arch Biochem Biophys 2016; 606:143-50. [PMID: 27495739 DOI: 10.1016/j.abb.2016.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 07/29/2016] [Accepted: 08/01/2016] [Indexed: 11/18/2022]
Abstract
RNase H fold protein PF2046 of Pyrococcus furiosus is a 3'-5' ssDNA exonuclease that cleaves after the second nucleotide from the 3' end of ssDNA and prefers poly-dT over poly-dA as a substrate. In our crystal structure of PF2046 complexed with an oligonucleotide of four thymidine nucleotides (dT4), PF2046 accommodates dT4 tightly in a groove and imposes steric hindrance on dT4 mainly by Phe220 such that dT4 assumes the A-form. As poly-dA prefer B-form due to the stereochemical restrictions, the A-form ssDNA binding by PF2046 should disfavor the processing of poly-dA. Phe220 variants display reduced activity toward poly-dA and the A-form appears to be a prerequisite for the processing by PF2046.
Collapse
Affiliation(s)
- Junsoo Kim
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea; Institute for Life Sciences and Natural Resources, Korea University, Seoul 136-713, Republic of Korea
| | - Gerelt-Od Sambalkhundev
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea; Institute for Life Sciences and Natural Resources, Korea University, Seoul 136-713, Republic of Korea
| | - Sulhee Kim
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Jonghyeon Son
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Ah-Reum Han
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Sul-Min Ko
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea
| | - Kwang Yeon Hwang
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea.
| | - Woo Cheol Lee
- Division of Biotechnology, Korea University, Anam-Dong, Seongbuk-gu, Seoul 136-713, Republic of Korea; Institute for Life Sciences and Natural Resources, Korea University, Seoul 136-713, Republic of Korea.
| |
Collapse
|
35
|
Nucleic acid polymeric properties and electrostatics: Directly comparing theory and simulation with experiment. Adv Colloid Interface Sci 2016; 232:49-56. [PMID: 26482088 DOI: 10.1016/j.cis.2015.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/18/2015] [Accepted: 09/29/2015] [Indexed: 11/24/2022]
Abstract
Nucleic acids are biopolymers that carry genetic information and are also involved in various gene regulation functions such as gene silencing and protein translation. Because of their negatively charged backbones, nucleic acids are polyelectrolytes. To adequately understand nucleic acid folding and function, we need to properly describe its i) polymer/polyelectrolyte properties and ii) associating ion atmosphere. While various theories and simulation models have been developed to describe nucleic acids and the ions around them, many of these theories/simulations have not been well evaluated due to complexities in comparison with experiment. In this review, I discuss some recent experiments that have been strategically designed for straightforward comparison with theories and simulation models. Such data serve as excellent benchmarks to identify limitations in prevailing theories and simulation parameters.
Collapse
|
36
|
Chakraborty K, Khatua P, Bandyopadhyay S. Exploring ion induced folding of a single-stranded DNA oligomer from molecular simulation studies. Phys Chem Chem Phys 2016; 18:15899-910. [PMID: 27241311 DOI: 10.1039/c6cp00663a] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
One crucial issue in DNA hydration is the effect of salts on its conformational features. This has relevance in biology as cations present in the cellular environment shield the negative charges on the DNA backbone, thereby reducing the repulsive force between them. By screening the negative charges along the backbone, cations stabilize the folded structure of DNA. To study the effect of the added salt on single-stranded DNA (ss-DNA) conformations, we have performed room temperature molecular dynamics simulations of an aqueous solution containing the ss-DNA dodecamer with the 5'-CGCGAATTCGCG-3' sequence in the presence of 0.2, 0.5, and 0.8 M NaCl. Our calculations reveal that in the presence of the salt, the DNA molecule forms more collapsed coil-like conformations due to the screening of negative charges along the backbone. Additionally, we demonstrated that the formation of an octahedral inner-sphere complex by the strongly bound ion plays an important role in the stabilization of such folded conformation of DNA. Importantly, it is found that ion-DNA interactions can also explain the formation of non-sequential base stackings with longer lifetimes. Such non-sequential base stackings further stabilize the collapsed coil-like folded form of the DNA oligomer.
Collapse
Affiliation(s)
- Kaushik Chakraborty
- Molecular Modeling Laboratory, Department of Chemistry, Indian Institute of Technology, Kharagpur - 721302, India.
| | | | | |
Collapse
|
37
|
Nganou C, Kennedy SD, McCamant DW. Disagreement Between the Structure of the dTpT Thymine Pair Determined by NMR and Molecular Dynamics Simulations Using Amber 14 Force Fields. J Phys Chem B 2016; 120:1250-8. [PMID: 26836489 DOI: 10.1021/acs.jpcb.6b00191] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a disagreement between the predicted structures of the dTpT thymine pair (thymidylyl(3' → 5')thymidine) using nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations using the AMBER ff14SB and ff14 + ε/ζOL1 + χOL4 force fields for DNA. The NMR structure was determined using NOE couplings to thymine's H6 and J(HH) couplings between sugar protons. The MD simulation used replica exchange methods to produce converged statistics in a 500 ns trajectory. NMR data indicate that both thymine nucleotides in the pair display an anti conformation of B-DNA, while the MD simulations predict a structure in which the 5'-thymine is flipped into a syn conformation and the 3'-thymine is in an anti conformation. The syn conformation of the 5'-thymine predicted by MD appears by a ∼ 180-deg flip of the glycosidic angle in comparison to the B-form anti structure. Differences in the distortion of the sugar pucker between 5'-thymine and 3'-thymine further highlighted the surprisingly different conformation of the 5'- and 3'-ends. While both MD and NMR indicate the deoxyribose sugars to be primarily in the 2'-endo conformation typical of B-form DNA, the MD simulations predict a more twisted conformation (2'-endo/1'-exo) for the 5'-sugar and significant flexibility of C3' of the 3'-sugar. We conclude that the current AMBER force field does not accurately predict the conformation of single-stranded thymine, in agreement with previous work investigating single-stranded DNA.
Collapse
Affiliation(s)
- Collins Nganou
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| | - Scott D Kennedy
- Department of Biochemistry and Biophysics, University of Rochester , Rochester, New York 14642, United States
| | - David W McCamant
- Department of Chemistry, University of Rochester , Rochester, New York 14627, United States
| |
Collapse
|
38
|
Capobianco A, Caruso T, Peluso A. Hole delocalization over adenine tracts in single stranded DNA oligonucleotides. Phys Chem Chem Phys 2016; 17:4750-6. [PMID: 25589467 DOI: 10.1039/c4cp04282d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Adiabatic ionization energies of single stranded DNA oligonucleotides containing adenine tracts of different sizes have been computed at the DFT level and compared with the oxidation potentials determined by differential pulse voltammetry. Geometry optimizations have been performed at the full quantum mechanical level, including the sugar phosphate backbone and solvent effects. The observed progressive lowering of the ionization energy upon increasing the number of consecutive adenines is well predicted, the computed ionization potential shifts being in very good agreement with the experimental outcomes, both by using pure and hybrid functionals. The spin density of the oligonucleotide radical cations is distributed almost over the whole adenine tract, forming delocalized polarons.
Collapse
Affiliation(s)
- Amedeo Capobianco
- Dipartimento di Chimica e Biologia, Università di Salerno, I-84084 Fisciano, SA, Italy.
| | | | | |
Collapse
|
39
|
González-Olvera JC, Martínez-Reyes J, González-Jasso E, Pless RC. Determination of pKa values for deprotonable nucleobases in short model oligonucleotides. Biophys Chem 2015; 206:58-65. [PMID: 26188860 DOI: 10.1016/j.bpc.2015.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 07/01/2015] [Accepted: 07/06/2015] [Indexed: 10/23/2022]
Abstract
The deprotonation of ionizable nucleobases centrally placed in short model oligonucleotides was examined under different physical conditions, using UV absorption spectroscopy. The oligonucleotide sequences were designed so that only the central base would be ionized over the pH range examined. pKa values of 9.90±0.01 and 9.34±0.04 were determined for the guanine group in the oligomer d-ACAGCAC and 2'-deoxyguanosine, respectively, both at 25°C and 0.1M NaCl. Lengthening the oligonucleotide up to the tridecamer stage further increases the pKa of the central guanine moiety. Electrolyte concentration, temperature, and mixed water-ethanol solvents affect the acidity of the central base. Changes in the sequence surrounding the central guanine can also have a significant effect, especially in the case of strongly stacking sequences. The pKa values were also determined for the hepta(2'-O-methyl)ribonucleotide and the heptamer PNA of identical sequence, as well as for oligodeoxyribonucleotides with different deprotonable bases, viz. thymine, uracil, or hypoxanthine, in the central position. The results are interpreted in terms of the electric-field effect exerted on the departing proton by the negative electric charges located on the internucleotide phosphate groups, and calculations show this effect to approximately explain the magnitude of the pKa difference observed between the deoxyriboheptanucleotide and its electroneutral PNA analogue.
Collapse
Affiliation(s)
- Julio C González-Olvera
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Instituto Politécnico Nacional, Querétaro, Querétaro 76090, Mexico
| | - José Martínez-Reyes
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Instituto Politécnico Nacional, Querétaro, Querétaro 76090, Mexico
| | - Eva González-Jasso
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Instituto Politécnico Nacional, Querétaro, Querétaro 76090, Mexico
| | - Reynaldo C Pless
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Instituto Politécnico Nacional, Querétaro, Querétaro 76090, Mexico.
| |
Collapse
|
40
|
Pathigoolla A, Sureshan KM. Synthesis of Triazole-linked Homonucleoside Polymers through Topochemical Azide-Alkyne Cycloaddition. Angew Chem Int Ed Engl 2014; 53:9522-5. [DOI: 10.1002/anie.201404797] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Indexed: 12/24/2022]
|
41
|
Pathigoolla A, Sureshan KM. Synthesis of Triazole-linked Homonucleoside Polymers through Topochemical Azide-Alkyne Cycloaddition. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201404797] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
42
|
Transgenic mouse lines subdivide external segment of the globus pallidus (GPe) neurons and reveal distinct GPe output pathways. J Neurosci 2014; 34:2087-99. [PMID: 24501350 DOI: 10.1523/jneurosci.4646-13.2014] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cell-type diversity in the brain enables the assembly of complex neural circuits, whose organization and patterns of activity give rise to brain function. However, the identification of distinct neuronal populations within a given brain region is often complicated by a lack of objective criteria to distinguish one neuronal population from another. In the external segment of the globus pallidus (GPe), neuronal populations have been defined using molecular, anatomical, and electrophysiological criteria, but these classification schemes are often not generalizable across preparations and lack consistency even within the same preparation. Here, we present a novel use of existing transgenic mouse lines, Lim homeobox 6 (Lhx6)-Cre and parvalbumin (PV)-Cre, to define genetically distinct cell populations in the GPe that differ molecularly, anatomically, and electrophysiologically. Lhx6-GPe neurons, which do not express PV, are concentrated in the medial portion of the GPe. They have lower spontaneous firing rates, narrower dynamic ranges, and make stronger projections to the striatum and substantia nigra pars compacta compared with PV-GPe neurons. In contrast, PV-GPe neurons are more concentrated in the lateral portions of the GPe. They have narrower action potentials, deeper afterhyperpolarizations, and make stronger projections to the subthalamic nucleus and parafascicular nucleus of the thalamus. These electrophysiological and anatomical differences suggest that Lhx6-GPe and PV-GPe neurons participate in different circuits with the potential to contribute to different aspects of motor function and dysfunction in disease.
Collapse
|
43
|
Scholl ZN, Rabbi M, Lee D, Manson L, S-Gracz H, Marszalek PE. Origin of overstretching transitions in single-stranded nucleic acids. PHYSICAL REVIEW LETTERS 2013; 111:188302. [PMID: 24237568 DOI: 10.1103/physrevlett.111.188302] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 08/14/2013] [Indexed: 06/02/2023]
Abstract
We combined single-molecule force spectroscopy with nuclear magnetic resonance measurements and molecular mechanics simulations to examine overstretching transitions in single-stranded nucleic acids. In single-stranded DNA and single-stranded RNA there is a low-force transition that involves unwinding of the helical structure, along with base unstacking. We determined that the high-force transition that occurs in polydeoxyadenylic acid single-stranded DNA is caused by the cooperative forced flipping of the dihedral angle formed between four atoms, O5'-C5'-C4'-C3' (γ torsion), in the nucleic acid backbone within the canonical B-type helix. The γ torsion also flips under force in A-type helices, where the helix is shorter and wider as compared to the B-type helix, but this transition is less cooperative than in the B type and does not generate a high-force plateau in the force spectrums of A-type helices. We find that a similar high-force transition can be induced in polyadenylic acid single-stranded RNA by urea, presumably due to disrupting the intramolecular hydrogen bonding in the backbone. We hypothesize that a pronounced high-force transition observed for B-type helices of double stranded DNA also involves a cooperative flip of the γ torsion. These observations suggest new fundamental relationships between the canonical structures of single-and double-stranded DNA and the mechanism of their molecular elasticity.
Collapse
Affiliation(s)
- Zackary N Scholl
- Program in Computational Biology and Bioinformatics, Duke University, Durham, North Carolina 27708, USA
| | | | | | | | | | | |
Collapse
|
44
|
Sztuba-Solinska J, Teramoto T, Rausch JW, Shapiro BA, Padmanabhan R, Le Grice SFJ. Structural complexity of Dengue virus untranslated regions: cis-acting RNA motifs and pseudoknot interactions modulating functionality of the viral genome. Nucleic Acids Res 2013; 41:5075-89. [PMID: 23531545 PMCID: PMC3643606 DOI: 10.1093/nar/gkt203] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The Dengue virus (DENV) genome contains multiple cis-acting elements required for translation and replication. Previous studies indicated that a 719-nt subgenomic minigenome (DENV-MINI) is an efficient template for translation and (−) strand RNA synthesis in vitro. We performed a detailed structural analysis of DENV-MINI RNA, combining chemical acylation techniques, Pb2+ ion-induced hydrolysis and site-directed mutagenesis. Our results highlight protein-independent 5′–3′ terminal interactions involving hybridization between recognized cis-acting motifs. Probing analyses identified tandem dumbbell structures (DBs) within the 3′ terminus spaced by single-stranded regions, internal loops and hairpins with embedded GNRA-like motifs. Analysis of conserved motifs and top loops (TLs) of these dumbbells, and their proposed interactions with downstream pseudoknot (PK) regions, predicted an H-type pseudoknot involving TL1 of the 5′ DB and the complementary region, PK2. As disrupting the TL1/PK2 interaction, via ‘flipping’ mutations of PK2, previously attenuated DENV replication, this pseudoknot may participate in regulation of RNA synthesis. Computer modeling implied that this motif might function as autonomous structural/regulatory element. In addition, our studies targeting elements of the 3′ DB and its complementary region PK1 indicated that communication between 5′–3′ terminal regions strongly depends on structure and sequence composition of the 5′ cyclization region.
Collapse
Affiliation(s)
- Joanna Sztuba-Solinska
- RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA, Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, USA and CCR Nanobiology Program, Computational RNA Structure Group, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Tadahisa Teramoto
- RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA, Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, USA and CCR Nanobiology Program, Computational RNA Structure Group, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Jason W. Rausch
- RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA, Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, USA and CCR Nanobiology Program, Computational RNA Structure Group, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Bruce A. Shapiro
- RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA, Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, USA and CCR Nanobiology Program, Computational RNA Structure Group, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Radhakrishnan Padmanabhan
- RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA, Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, USA and CCR Nanobiology Program, Computational RNA Structure Group, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Stuart F. J. Le Grice
- RT Biochemistry Section, HIV Drug Resistance Program, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA, Department of Microbiology and Immunology, Georgetown University School of Medicine, Washington, DC 20057, USA and CCR Nanobiology Program, Computational RNA Structure Group, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
- *To whom correspondence should be addressed. Tel: +1 301 846 5256; Fax: +1 301 846 5256;
| |
Collapse
|
45
|
Charlebois I, Gravel C, Arrad N, Boissinot M, Bergeron MG, Leclerc M. Impact of DNA sequence and oligonucleotide length on a polythiophene-based fluorescent DNA biosensor. Macromol Biosci 2013; 13:717-22. [PMID: 23512409 DOI: 10.1002/mabi.201200469] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/06/2013] [Indexed: 12/25/2022]
Abstract
DNA hybridization is a universal and specific mechanism for the recognition of biological targets. Some cationic polythiophene transducers sensitive to DNA structure have been previously utilized to detect such biomolecules. Further characterization of these systems indicates that both DNA sequence composition and length modulate the biosensor performance. It appears that different repeated sequence patterns cause different conformational changes of the polythiophene, from a more relaxed form to an extremely rigid one. A length difference between the DNA oligonucleotide probe and target has a detrimental effect on the fluorescent signal, but it can be attenuated by changing the sequence composition of the protruding target sequence. This demonstrates that the nature of DNA can be critical for hybridization-based detection systems.
Collapse
Affiliation(s)
- Isabelle Charlebois
- Centre de recherche du CHU de Québec, Département de Microbiologie-infectiologie et immunologie, Faculté de médecine, Université Laval, 2705 Laurier Blvd., Quebec City, QC, G1V 4G2, Canada
| | | | | | | | | | | |
Collapse
|
46
|
Parker TM, Hohenstein EG, Parrish RM, Hud NV, Sherrill CD. Quantum-mechanical analysis of the energetic contributions to π stacking in nucleic acids versus rise, twist, and slide. J Am Chem Soc 2013; 135:1306-16. [PMID: 23265256 DOI: 10.1021/ja3063309] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Symmetry-adapted perturbation theory (SAPT) is applied to pairs of hydrogen-bonded nucleobases to obtain the energetic components of base stacking (electrostatic, exchange-repulsion, induction/polarization, and London dispersion interactions) and how they vary as a function of the helical parameters Rise, Twist, and Slide. Computed average values of Rise and Twist agree well with experimental data for B-form DNA from the Nucleic Acids Database, even though the model computations omitted the backbone atoms (suggesting that the backbone in B-form DNA is compatible with having the bases adopt their ideal stacking geometries). London dispersion forces are the most important attractive component in base stacking, followed by electrostatic interactions. At values of Rise typical of those in DNA (3.36 Å), the electrostatic contribution is nearly always attractive, providing further evidence for the importance of charge-penetration effects in π-π interactions (a term neglected in classical force fields). Comparison of the computed stacking energies with those from model complexes made of the "parent" nucleobases purine and 2-pyrimidone indicates that chemical substituents in DNA and RNA account for 20-40% of the base-stacking energy. A lack of correspondence between the SAPT results and experiment for Slide in RNA base-pair steps suggests that the backbone plays a larger role in determining stacking geometries in RNA than in B-form DNA. In comparisons of base-pair steps with thymine versus uracil, the thymine methyl group tends to enhance the strength of the stacking interaction through a combination of dispersion and electrosatic interactions.
Collapse
Affiliation(s)
- Trent M Parker
- Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry, and School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, USA
| | | | | | | | | |
Collapse
|
47
|
Kuruvilla E, Schuster GB, Hud NV. Enhanced nonenzymatic ligation of homopurine miniduplexes: support for greater base stacking in a pre-RNA world. Chembiochem 2012; 14:45-8. [PMID: 23225671 DOI: 10.1002/cbic.201200601] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Indexed: 11/07/2022]
Abstract
The ancestors of RNA? There is a long-standing proposal that contemporary nucleic acids might have evolved from RNA-like polymers that utilized only purine-purine base pairs. Here we demonstrate the great advantage that increased nucleobase stacking area provides for nonenzymatic ligation.
Collapse
Affiliation(s)
- Elizabeth Kuruvilla
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
| | | | | |
Collapse
|
48
|
Sim AYL, Lipfert J, Herschlag D, Doniach S. Salt dependence of the radius of gyration and flexibility of single-stranded DNA in solution probed by small-angle x-ray scattering. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:021901. [PMID: 23005779 DOI: 10.1103/physreve.86.021901] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Indexed: 06/01/2023]
Abstract
Short single-stranded nucleic acids are ubiquitous in biological processes; understanding their physical properties provides insights to nucleic acid folding and dynamics. We used small-angle x-ray scattering to study 8-100 residue homopolymeric single-stranded DNAs in solution, without external forces or labeling probes. Poly-T's structural ensemble changes with increasing ionic strength in a manner consistent with a polyelectrolyte persistence length theory that accounts for molecular flexibility. For any number of residues, poly-A is consistently more elongated than poly-T, likely due to the tendency of A residues to form stronger base-stacking interactions than T residues.
Collapse
Affiliation(s)
- Adelene Y L Sim
- Applied Physics Department, Stanford University, Stanford, California 94305, USA
| | | | | | | |
Collapse
|
49
|
Dickman R, Manyanga F, Brewood GP, Fish DJ, Fish CA, Summers C, Horne MT, Benight AS. Thermodynamic contributions of 5’- and 3’-single strand dangling-ends to the stability of short duplex DNAs. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/jbpc.2012.31001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
50
|
Eichhorn CD, Feng J, Suddala KC, Walter NG, Brooks CL, Al-Hashimi HM. Unraveling the structural complexity in a single-stranded RNA tail: implications for efficient ligand binding in the prequeuosine riboswitch. Nucleic Acids Res 2011; 40:1345-55. [PMID: 22009676 PMCID: PMC3273816 DOI: 10.1093/nar/gkr833] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Single-stranded RNAs (ssRNAs) are ubiquitous RNA elements that serve diverse functional roles. Much of our understanding of ssRNA conformational behavior is limited to structures in which ssRNA directly engages in tertiary interactions or is recognized by proteins. Little is known about the structural and dynamic behavior of free ssRNAs at atomic resolution. Here, we report the collaborative application of nuclear magnetic resonance (NMR) and replica exchange molecular dynamics (REMD) simulations to characterize the 12 nt ssRNA tail derived from the prequeuosine riboswitch. NMR carbon spin relaxation data and residual dipolar coupling measurements reveal a flexible yet stacked core adopting an A-form-like conformation, with the level of order decreasing toward the terminal ends. An A-to-C mutation within the polyadenine tract alters the observed dynamics consistent with the introduction of a dynamic kink. Pre-ordering of the tail may increase the efficacy of ligand binding above that achieved by a random-coil ssRNA. The REMD simulations recapitulate important trends in the NMR data, but suggest more internal motions than inferred from the NMR analysis. Our study unmasks a previously unappreciated level of complexity in ssRNA, which we believe will also serve as an excellent model system for testing and developing computational force fields.
Collapse
Affiliation(s)
- Catherine D Eichhorn
- Chemical Biology Doctoral Program, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | | | | | | |
Collapse
|