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Hollmann F, Sanchis J, Reetz MT. Learning from Protein Engineering by Deconvolution of Multi-Mutational Variants. Angew Chem Int Ed Engl 2024; 63:e202404880. [PMID: 38884594 DOI: 10.1002/anie.202404880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 06/05/2024] [Accepted: 06/06/2024] [Indexed: 06/18/2024]
Abstract
This review analyzes a development in biochemistry, enzymology and biotechnology that originally came as a surprise. Following the establishment of directed evolution of stereoselective enzymes in organic chemistry, the concept of partial or complete deconvolution of selective multi-mutational variants was introduced. Early deconvolution experiments of stereoselective variants led to the finding that mutations can interact cooperatively or antagonistically with one another, not just additively. During the past decade, this phenomenon was shown to be general. In some studies, molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) computations were performed in order to shed light on the origin of non-additivity at all stages of an evolutionary upward climb. Data of complete deconvolution can be used to construct unique multi-dimensional rugged fitness pathway landscapes, which provide mechanistic insights different from traditional fitness landscapes. Along a related line, biochemists have long tested the result of introducing two point mutations in an enzyme for mechanistic reasons, followed by a comparison of the respective double mutant in so-called double mutant cycles, which originally showed only additive effects, but more recently also uncovered cooperative and antagonistic non-additive effects. We conclude with suggestions for future work, and call for a unified overall picture of non-additivity and epistasis.
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Affiliation(s)
- Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ, Delft, Netherlands
| | - Joaquin Sanchis
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, 3052, Australia
| | - Manfred T Reetz
- Max-Plank-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45481, Mülheim, Germany
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
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2
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Roberts JM, Beck JD, Pollock TB, Bendixsen DP, Hayden EJ. RNA sequence to structure analysis from comprehensive pairwise mutagenesis of multiple self-cleaving ribozymes. eLife 2023; 12:80360. [PMID: 36655987 PMCID: PMC9901934 DOI: 10.7554/elife.80360] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 12/28/2022] [Indexed: 01/20/2023] Open
Abstract
Self-cleaving ribozymes are RNA molecules that catalyze the cleavage of their own phosphodiester backbones. These ribozymes are found in all domains of life and are also a tool for biotechnical and synthetic biology applications. Self-cleaving ribozymes are also an important model of sequence-to-function relationships for RNA because their small size simplifies synthesis of genetic variants and self-cleaving activity is an accessible readout of the functional consequence of the mutation. Here, we used a high-throughput experimental approach to determine the relative activity for every possible single and double mutant of five self-cleaving ribozymes. From this data, we comprehensively identified non-additive effects between pairs of mutations (epistasis) for all five ribozymes. We analyzed how changes in activity and trends in epistasis map to the ribozyme structures. The variety of structures studied provided opportunities to observe several examples of common structural elements, and the data was collected under identical experimental conditions to enable direct comparison. Heatmap-based visualization of the data revealed patterns indicating structural features of the ribozymes including paired regions, unpaired loops, non-canonical structures, and tertiary structural contacts. The data also revealed signatures of functionally critical nucleotides involved in catalysis. The results demonstrate that the data sets provide structural information similar to chemical or enzymatic probing experiments, but with additional quantitative functional information. The large-scale data sets can be used for models predicting structure and function and for efforts to engineer self-cleaving ribozymes.
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Affiliation(s)
- Jessica M Roberts
- Biomolecular Sciences Graduate Programs, Boise State UniversityBoiseUnited States
| | - James D Beck
- Computing PhD Program, Boise State UniversityBoiseUnited States
| | - Tanner B Pollock
- Department of Biological Science, Boise State UniversityBoiseUnited States
| | - Devin P Bendixsen
- Biomolecular Sciences Graduate Programs, Boise State UniversityBoiseUnited States
| | - Eric J Hayden
- Biomolecular Sciences Graduate Programs, Boise State UniversityBoiseUnited States
- Computing PhD Program, Boise State UniversityBoiseUnited States
- Department of Biological Science, Boise State UniversityBoiseUnited States
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3
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Cooperativity and Allostery in RNA Systems. Methods Mol Biol 2020; 2253:255-271. [PMID: 33315228 DOI: 10.1007/978-1-0716-1154-8_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
Allostery is among the most basic biological principles employed by biological macromolecules to achieve a biologically active state in response to chemical cues. Although initially used to describe the impact of small molecules on the conformation and activity of protein enzymes, the definition of this term has been significantly broadened to describe long-range conformational change of macromolecules in response to small or large effectors. Such a broad definition could be applied to RNA molecules, which do not typically serve as protein-free cellular enzymes but fold and form macromolecular assemblies with the help of various ligand molecules, including ions and proteins. Ligand-induced allosteric changes in RNA molecules are often accompanied by cooperative interactions between RNA and its ligand, thus streamlining the folding and assembly pathways. This chapter provides an overview of the interplay between cooperativity and allostery in RNA systems and outlines methods to study these two biological principles.
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4
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Estrada-Peña A, Villar M, Artigas-Jerónimo S, López V, Alberdi P, Cabezas-Cruz A, de la Fuente J. Use of Graph Theory to Characterize Human and Arthropod Vector Cell Protein Response to Infection With Anaplasma phagocytophilum. Front Cell Infect Microbiol 2018; 8:265. [PMID: 30123779 PMCID: PMC6086010 DOI: 10.3389/fcimb.2018.00265] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 07/13/2018] [Indexed: 12/30/2022] Open
Abstract
One of the major challenges in modern biology is the use of large omics datasets for the characterization of complex processes such as cell response to infection. These challenges are even bigger when analyses need to be performed for comparison of different species including model and non-model organisms. To address these challenges, the graph theory was applied to characterize the tick vector and human cell protein response to infection with Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis. A network of interacting proteins and cell processes clustered in biological pathways, and ranked with indexes representing the topology of the proteome was prepared. The results demonstrated that networks of functionally interacting proteins represented in both infected and uninfected cells can describe the complete set of host cell processes and metabolic pathways, providing a deeper view of the comparative host cell response to pathogen infection. The results demonstrated that changes in the tick proteome were driven by modifications in protein representation in response to A. phagocytophilum infection. Pathogen infection had a higher impact on tick than human proteome. Since most proteins were linked to several cell processes, the changes in protein representation affected simultaneously different biological pathways. The method allowed discerning cell processes that were affected by pathogen infection from those that remained unaffected. The results supported that human neutrophils but not tick cells limit pathogen infection through differential representation of ras-related proteins. This methodological approach could be applied to other host-pathogen models to identify host derived key proteins in response to infection that may be used to develop novel control strategies for arthropod-borne pathogens.
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Affiliation(s)
| | - Margarita Villar
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC, Universidad de Castilla-La Mancha (UCLM), Junta de Comunidades de Castilla - La Mancha (JCCM), Ciudad Real, Spain
| | - Sara Artigas-Jerónimo
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC, Universidad de Castilla-La Mancha (UCLM), Junta de Comunidades de Castilla - La Mancha (JCCM), Ciudad Real, Spain
| | - Vladimir López
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC, Universidad de Castilla-La Mancha (UCLM), Junta de Comunidades de Castilla - La Mancha (JCCM), Ciudad Real, Spain
| | - Pilar Alberdi
- SaBio, Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC, Universidad de Castilla-La Mancha (UCLM), Junta de Comunidades de Castilla - La Mancha (JCCM), Ciudad Real, Spain
| | - Alejandro Cabezas-Cruz
- UMR Biologie Moléculaire et Immunologie Parasitaires (BIPAR), INRA, Agence Nationale de Sécurité Sanitairede l'Alimentation, de l'Environnement et du Travail (ANSES), Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, Maisons-Alfort, France.,Faculty of Science, University of South Bohemia, Ceské Budějovice, Czechia.,Institute of Parasitology, Biology Center, Czech Academy of Sciences, Ceské Budějovice, Czechia
| | - José de la Fuente
- Facultad de Veterinaria, Universidad de Zaragoza, Zaragoza, Spain.,Department of Veterinary Pathobiology, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, OK, United States
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5
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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: 41] [Impact Index Per Article: 6.8] [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.
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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
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6
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Bingaman JL, Gonzalez IY, Wang B, Bevilacqua PC. Activation of the glmS Ribozyme Nucleophile via Overdetermined Hydrogen Bonding. Biochemistry 2017; 56:4313-4317. [DOI: 10.1021/acs.biochem.7b00662] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jamie L. Bingaman
- Department
of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center
for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Inanllely Y. Gonzalez
- Department
of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Bo Wang
- Department
of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Philip C. Bevilacqua
- Department
of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Center
for RNA Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department
of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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7
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Wang J, Dong P, Wu W, Pan X, Liang X. High-throughput thermal stability assessment of DNA hairpins based on high resolution melting. J Biomol Struct Dyn 2016; 36:1-13. [PMID: 28024437 DOI: 10.1080/07391102.2016.1266967] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
On the basis of high-resolution melting, a high-throughput approach to measure melting temperatures (Tms) of short DNA hairpins was developed. With this method, Tms of thousands of triloop, tetraloop, and pentaloop hairpins involving various loop sequences and various closing base pairs (cbp) were obtained in hours. The stability of triloop hairpins decreased with the change of cbp (5'-3') in the order of c-g > g-c > t-a ≥ a-t, showing that the cbp of 5'-Pyr-Pur-3' (Pyr = pyrimidine, Pur = purine) contributed more stability than 5'-Pur-Pyr-3'. For tetraloop hairpins, GNNA, GNAB, and CNNG (N = A, G, C, or T; B = G, C, or T) were found to be highly stable irrespective of the cbp type. TNNA was also stable in both g-c and a-t families, while CGNA only in the c-g family. Pentaloop hairpins of cTGNAGg, cGNYNAg (Y = T or C) and cCGNNAg were exceptionally stable motifs. In most cases, pyrimidine-rich loops were more favorable to stabilize the whole structure than purine-rich ones. The present approach showed a good performance in assessing the thermal stability of large amounts of DNA hairpins comprehensively. These data are useful to understand the sequence dependence of the stability of DNA secondary structures and promising to improve the structure simulation by consummating basic databases.
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Affiliation(s)
- Jing Wang
- a College of Food Science and Engineering , Ocean University of China , Qingdao 266003 , China
| | - Ping Dong
- a College of Food Science and Engineering , Ocean University of China , Qingdao 266003 , China
| | - Wei Wu
- a College of Food Science and Engineering , Ocean University of China , Qingdao 266003 , China
| | - Xiaoming Pan
- a College of Food Science and Engineering , Ocean University of China , Qingdao 266003 , China
| | - Xingguo Liang
- a College of Food Science and Engineering , Ocean University of China , Qingdao 266003 , China
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8
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Wang J, Pan X, Liang X. Assessment for Melting Temperature Measurement of Nucleic Acid by HRM. JOURNAL OF ANALYTICAL METHODS IN CHEMISTRY 2016; 2016:5318935. [PMID: 27833775 PMCID: PMC5090098 DOI: 10.1155/2016/5318935] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 08/04/2016] [Accepted: 09/06/2016] [Indexed: 06/06/2023]
Abstract
High resolution melting (HRM), with a high sensitivity to distinguish the nucleic acid species with small variations, has been widely applied in the mutation scanning, methylation analysis, and genotyping. For the aim of extending HRM for the evaluation of thermal stability of nucleic acid secondary structures on sequence dependence, we investigated effects of the dye of EvaGreen, metal ions, and impurities (such as dNTPs) on melting temperature (Tm ) measurement by HRM. The accuracy of HRM was assessed as compared with UV melting method, and little difference between the two methods was found when the DNA Tm was higher than 40°C. Both insufficiency and excessiveness of EvaGreen were found to give rise to a little bit higher Tm , showing that the proportion of dye should be considered for precise Tm measurement of nucleic acids. Finally, HRM method was also successfully used to measure Tm s of DNA triplex, hairpin, and RNA duplex. In conclusion, HRM can be applied in the evaluation of thermal stability of nucleic acid (DNA or RNA) or secondary structural elements (even when dNTPs are present).
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Affiliation(s)
- Jing Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Xiaoming Pan
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
| | - Xingguo Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China
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9
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Karabıyık H, Sevinçek R, Karabıyık H. π-Cooperativity effect on the base stacking interactions in DNA: is there a novel stabilization factor coupled with base pairing H-bonds? Phys Chem Chem Phys 2015; 16:15527-38. [PMID: 24953339 DOI: 10.1039/c4cp00997e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The results from absolutely localized molecular orbital (ALMO)-energy decomposition analysis (EDA) and ALMO-charge transfer analysis (CTA) at M06-2X/cc-pVTZ level reveal that double-proton transfer (DPT) reactions through base pairing H-bonds have nonignorable effects on the stacking energies of dinucleotide steps, which introduces us to a novel stabilization (or destabilization) factor in the DNA duplex. Thus, intra- and inter-strand base stacking interactions are coalesced with each other mediated by H-bridged quasirings between base pairs. Changes in stacking energies of dinucleotide steps depending on the positions of H atoms are due to variations in local aromaticities of individual nucleobases, manifesting π-cooperativity effects. CT analyses show that dispersion forces in dinucleotide steps can lead to radical changes in the redox properties of nucleobases, in particular those of adenine and guanine stacked dimers in a strand. Besides Watson-Crick rules, novel base pairing rules were propounded by considering CT results. According to these, additional base pairing through π-stacks of nucleobases in dinucleotide steps does not cause any intrinsic oxidative damage to the associated nucleobases throughout DPT.
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Affiliation(s)
- Hande Karabıyık
- Department of Physics, Dokuz Eylül University, 35160-Tınaztepe, İzmir, Turkey.
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10
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Halder S, Krishnan Y. Design of ultrasensitive DNA-based fluorescent pH sensitive nanodevices. NANOSCALE 2015; 7:10008-10012. [PMID: 25990365 DOI: 10.1039/c5nr01158b] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Here we tune the pH sensitivity of a DNA-based conformational switch, called the I-switch, to yield a set of fluorescent pH sensitive nanodevices with a collective, expanded pH sensing regime from 5.3 to 7.5. The expanded pH regime of this new family of I-switches originates from a dramatic improvement in the overall percentage signal change in response to pH of these nanodevices.
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Affiliation(s)
- Saheli Halder
- National Centre for Biological Sciences, TIFR, GKVK, Bellary Road, Bangalore 560 065, India
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11
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Roles of the amino group of purine bases in the thermodynamic stability of DNA base pairing. Molecules 2014; 19:11613-27. [PMID: 25100254 PMCID: PMC6271411 DOI: 10.3390/molecules190811613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 01/19/2023] Open
Abstract
The energetic aspects of hydrogen-bonded base-pair interactions are important for the design of functional nucleotide analogs and for practical applications of oligonucleotides. The present study investigated the contribution of the 2-amino group of DNA purine bases to the thermodynamic stability of oligonucleotide duplexes under different salt and solvent conditions, using 2'-deoxyriboinosine (I) and 2'-deoxyribo-2,6-diaminopurine (D) as non-canonical nucleotides. The stability of DNA duplexes was changed by substitution of a single base pair in the following order: G•C > D•T ≈ I•C > A•T > G•T > I•T. The apparent stabilization energy due to the presence of the 2-amino group of G and D varied depending on the salt concentration, and decreased in the water-ethanol mixed solvent. The effects of salt concentration on the thermodynamics of DNA duplexes were found to be partially sequence-dependent, and the 2-amino group of the purine bases might have an influence on the binding of ions to DNA through the formation of a stable base-paired structure. Our results also showed that physiological salt conditions were energetically favorable for complementary base recognition, and conversely, low salt concentration media and ethanol-containing solvents were effective for low stringency oligonucleotide hybridization, in the context of conditions employed in this study.
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12
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Villani G. Coupling between hydrogen atoms transfer and stacking interaction in adenine-thymine/guanine-cytosine complexes: a theoretical study. J Phys Chem B 2014; 118:5439-52. [PMID: 24813562 DOI: 10.1021/jp502792r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four different complexes of two base pairs, an adenine-thymine and a guanine-cytosine one, have been studied in order to understand the modifications induced by the staking interaction between the two base pairs on the hydrogen atoms transfers between the bases in either base pair. The inclusion of these two kinds of interactions allows us to clarify if some properties, as the mechanism of hydrogen transfer, is exclusively a local effect of a base pair or can be modified by a more long-range interaction between the base pairs. The results on these four complexes are compared with those of the monomeric systems, the A-T and G-C base pair, and with those of the A-T and G-C dimers. The specificity of each complex and of each hydrogen bond has been analyzed.
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Affiliation(s)
- Giovanni Villani
- Istituto di Chimica dei Composti OrganoMetallici, ICCOM-UOS Pisa Area della Ricerca del CNR, Via G. Moruzzi, 1, I-56124 Pisa, Italy
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13
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Strulson CA, Boyer JA, Whitman EE, Bevilacqua PC. Molecular crowders and cosolutes promote folding cooperativity of RNA under physiological ionic conditions. RNA (NEW YORK, N.Y.) 2014; 20:331-47. [PMID: 24442612 PMCID: PMC3923128 DOI: 10.1261/rna.042747.113] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 11/22/2013] [Indexed: 05/21/2023]
Abstract
Folding mechanisms of functional RNAs under idealized in vitro conditions of dilute solution and high ionic strength have been well studied. Comparatively little is known, however, about mechanisms for folding of RNA in vivo where Mg(2+) ion concentrations are low, K(+) concentrations are modest, and concentrations of macromolecular crowders and low-molecular-weight cosolutes are high. Herein, we apply a combination of biophysical and structure mapping techniques to tRNA to elucidate thermodynamic and functional principles that govern RNA folding under in vivo-like conditions. We show by thermal denaturation and SHAPE studies that tRNA folding cooperativity increases in physiologically low concentrations of Mg(2+) (0.5-2 mM) and K(+) (140 mM) if the solution is supplemented with physiological amounts (∼ 20%) of a water-soluble neutral macromolecular crowding agent such as PEG or dextran. Low-molecular-weight cosolutes show varying effects on tRNA folding cooperativity, increasing or decreasing it based on the identity of the cosolute. For those additives that increase folding cooperativity, the gain is manifested in sharpened two-state-like folding transitions for full-length tRNA over its secondary structural elements. Temperature-dependent SHAPE experiments in the absence and presence of crowders and cosolutes reveal extent of cooperative folding of tRNA on a nucleotide basis and are consistent with the melting studies. Mechanistically, crowding agents appear to promote cooperativity by stabilizing tertiary structure, while those low molecular cosolutes that promote cooperativity stabilize tertiary structure and/or destabilize secondary structure. Cooperative folding of functional RNA under physiological-like conditions parallels the behavior of many proteins and has implications for cellular RNA folding kinetics and evolution.
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Affiliation(s)
- Christopher A. Strulson
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Joshua A. Boyer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Elisabeth E. Whitman
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Philip C. Bevilacqua
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Corresponding authorE-mail
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14
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Nayak RK, Van Orden A. Counterion and polythymidine loop-length-dependent folding and thermodynamic stability of DNA hairpins reveal the unusual counterion-dependent stability of tetraloop hairpins. J Phys Chem B 2013; 117:13956-66. [PMID: 24144397 DOI: 10.1021/jp404832d] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Stem-loop DNA hairpins containing a 5-base-pair (bp) stem and single-stranded polythymidine loop were investigated using thermodynamic melting analysis and stopped-flow kinetics. These studies revealed the thermodynamic stability and folding kinetics as a function of loop length and counterion concentration. Our results show the unusually high thermodynamic stability for tetraloop or 4 poly(dT) loop hairpin as compared with longer loop length hairpins. Furthermore, this exceptional stability is highly counterion-dependent. For example, in the higher counterion concentration regime of 50 mM NaCl and above, the tetraloop hairpin displays enhanced stability as compared with longer loop length hairpins. However, at lower counterion concentration of 25 mM NaCl and below, the thermal stability of tetraloop hairpin is consistent with the longer loop hairpins. The enhanced stability of tetraloop hairpins at higher counterion concentration can be explained on the basis of the combined entropic effect of loop closure as well as base stacking in the loop regions. The stability of longer loop length hairpins at all counterion concentrations as well as tetraloop hairpin at lower counterion concentration can be explained on the basis of entropic effect of loop closure alone. The thermodynamic parameters at lower and higher counterion concentrations were determined to quantify the enhanced stability of base-stacking effects occurring at higher counterion concentrations. For example, for 100 mM NaCl, excess Gibbs energy and enthalpy due to base stacking within the tetraloops were measured to be -1.2 ± 0.14 and -3.28 ± 0.32 kcal/mol, respectively, whereas, no excess of Gibbs energy and enthalpy was observed for 0, 5, 10, and 25 mM NaCl. These findings suggest significant base-stacking interactions occurring in the loop region of the tetraloop hairpins at higher counterion concentration and less significant base-stacking interactions in the lower counterion concentration regime. We suggest that at higher counterion concentrations, hydrophobic collapse of the nucleotides in the loop may be enhanced due to the increased polarity of the solvent, thereby enhancing base-stacking interactions that contribute to unusually high stability.
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Affiliation(s)
- Rajesh K Nayak
- Department of Chemistry, Colorado State University , Fort Collins, Colorado 80523, United States
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15
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Curtis EA, Bartel DP. Synthetic shuffling and in vitro selection reveal the rugged adaptive fitness landscape of a kinase ribozyme. RNA (NEW YORK, N.Y.) 2013; 19:1116-1128. [PMID: 23798664 PMCID: PMC3708531 DOI: 10.1261/rna.037572.112] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 05/21/2013] [Indexed: 06/02/2023]
Abstract
The relationship between genotype and phenotype is often described as an adaptive fitness landscape. In this study, we used a combination of recombination, in vitro selection, and comparative sequence analysis to characterize the fitness landscape of a previously isolated kinase ribozyme. Point mutations present in improved variants of this ribozyme were recombined in vitro in more than 10(14) different arrangements using synthetic shuffling, and active variants were isolated by in vitro selection. Mutual information analysis of 65 recombinant ribozymes isolated in the selection revealed a rugged fitness landscape in which approximately one-third of the 91 pairs of positions analyzed showed evidence of correlation. Pairs of correlated positions overlapped to form densely connected networks, and groups of maximally connected nucleotides occurred significantly more often in these networks than they did in randomized control networks with the same number of links. The activity of the most efficient recombinant ribozyme isolated from the synthetically shuffled pool was 30-fold greater than that of any of the ribozymes used to build it, which indicates that synthetic shuffling can be a rich source of ribozyme variants with improved properties.
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Affiliation(s)
- Edward A. Curtis
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
- Department of Biology and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
- Department of Chemistry and Chemical Biology and Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts 02138, USA
| | - David P. Bartel
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, USA
- Department of Biology and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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16
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Zhang H, Guo J, Li D, Ng MTT, Lee JY, Lv B, Ng CW, Lee S, Shao F, Li T. Confirmation of quinolone-induced formation of gyrase–DNA conjugates using AFM. Bioorg Med Chem Lett 2013; 23:4622-6. [DOI: 10.1016/j.bmcl.2013.06.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 05/29/2013] [Accepted: 06/10/2013] [Indexed: 11/28/2022]
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17
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Kara M, Zacharias M. Theoretical studies of nucleic acids folding. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2013. [DOI: 10.1002/wcms.1146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Mahmut Kara
- Physics Department T38, Technical University Munich, Garching, Germany
| | - Martin Zacharias
- Martin Zacharias, Physics Department T38, Technical University Munich, Garching, Germany
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18
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Villani G. Theoretical investigation of the coupling between hydrogen-atom transfer and stacking interaction in adenine-thymine dimers. Chemphyschem 2013; 14:1256-63. [PMID: 23494877 DOI: 10.1002/cphc.201200971] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/07/2013] [Indexed: 12/13/2022]
Abstract
Three different dimers of the adenine-thymine (A-T) base pair are studied to point out the changes of important properties (structure, atomic charge, energy and so on) induced by coupling between the movement of the atoms in the hydrogen bonds and the stacking interaction. The comparison of these results with those for the A-T monomer system explains the role of the stacking interaction in the hydrogen-atom transfer in this biologically important base pair. The results support the idea that this coupling depends on the exact dimer considered and is different for the N-N and N-O hydrogen bonds. In particular, the correlation between the hydrogen transfer and the stacking interaction is more relevant for the N-N bridge than for the N-O one. Also, the two different mechanisms of two-hydrogen transfer (step by step and concerted) can be modified by the stacking interaction between the base pairs.
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Affiliation(s)
- Giovanni Villani
- Istituto di Chimica dei Composti OrganoMetallici, ICCOM-UOS Pisa, Area della Ricerca del CNR, Via G. Moruzzi 1, 56124 Pisa, Italy.
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19
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Villani G. Theoretical investigation of the coupling between hydrogen atoms transfer and stacking interaction in guanine–cytosine dimers. Phys Chem Chem Phys 2013; 15:19242-52. [DOI: 10.1039/c3cp52855c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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20
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Kwok CK, Sherlock ME, Bevilacqua PC. Decrease in RNA Folding Cooperativity by Deliberate Population of Intermediates in RNA G-Quadruplexes. Angew Chem Int Ed Engl 2012; 52:683-6. [DOI: 10.1002/anie.201206475] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 09/09/2012] [Indexed: 01/16/2023]
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21
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Kwok CK, Sherlock ME, Bevilacqua PC. Decrease in RNA Folding Cooperativity by Deliberate Population of Intermediates in RNA G-Quadruplexes. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206475] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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22
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Kuznetsov SV, Ansari A. A kinetic zipper model with intrachain interactions applied to nucleic acid hairpin folding kinetics. Biophys J 2012; 102:101-11. [PMID: 22225803 DOI: 10.1016/j.bpj.2011.11.4017] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 11/11/2011] [Accepted: 11/22/2011] [Indexed: 11/30/2022] Open
Abstract
Single-stranded DNA and RNA hairpin structures with 4-10 nucleotides (nt) in the loop and 5-8 basepairs (bp) in the stem fold on 10-100 μs timescale. In contrast, theoretical estimate of first contact time of two ends of an ideal semiflexible polymer of similar lengths (with persistence length ~2-nt) is 10-100 ns. We propose that this three-orders-of-magnitude difference between these two timescales is a result of roughness in the folding free energy surface arising from intrachain interactions. We present a statistical mechanical model that explicitly includes all misfolded microstates with nonnative Watson-Crick (WC) and non-WC contacts. Rates of interconversion between different microstates are described in terms of two adjustable parameters: the strength of the non-WC interactions (ΔG(nWC)) and the rate at which a basepair is formed adjacent to an existing basepair (k(bp)(+)). The model accurately reproduces the temperature and loop-length dependence of the measured relaxation rates in temperature-jump studies of a 7-bp stem, single-stranded DNA hairpin with 4-20-nt-long poly(dT) loops, with ΔG(nWC) ≈ -2.4 kcal/mol and k(bp)(+) ≥ (1 ns)(-1), in 100 mM NaCl. Thus, our model provides a microscopic interpretation of the slow hairpin folding times as well as an estimate of the strength of intrachain interactions.
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Affiliation(s)
- Serguei V Kuznetsov
- Department of Physics, University of Illinois at Chicago, Chicago, Illinois, USA
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23
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Notash B, Safari N, Khavasi HR. Anion-controlled structural motif in one-dimensional coordination networks via cooperative weak noncovalent interactions. CrystEngComm 2012. [DOI: 10.1039/c2ce25554e] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Kannan S, Zacharias M. Role of the closing base pair for d(GCA) hairpin stability: free energy analysis and folding simulations. Nucleic Acids Res 2011; 39:8271-80. [PMID: 21724608 PMCID: PMC3201870 DOI: 10.1093/nar/gkr541] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/11/2011] [Accepted: 06/13/2011] [Indexed: 01/17/2023] Open
Abstract
Hairpin loops belong to the most important structural motifs in folded nucleic acids. The d(GNA) sequence in DNA can form very stable trinucleotide hairpin loops depending, however, strongly on the closing base pair. Replica-exchange molecular dynamics (REMD) were employed to study hairpin folding of two DNA sequences, d(gcGCAgc) and d(cgGCAcg), with the same central loop motif but different closing base pairs starting from single-stranded structures. In both cases, conformations of the most populated conformational cluster at the lowest temperature showed close agreement with available experimental structures. For the loop sequence with the less stable G:C closing base pair, an alternative loop topology accumulated as second most populated conformational state indicating a possible loop structural heterogeneity. Comparative-free energy simulations on induced loop unfolding indicated higher stability of the loop with a C:G closing base pair by ~3 kcal mol(-1) (compared to a G:C closing base pair) in very good agreement with experiment. The comparative energetic analysis of sampled unfolded, intermediate and folded conformational states identified electrostatic and packing interactions as the main contributions to the closing base pair dependence of the d(GCA) loop stability.
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Affiliation(s)
- Srinivasaraghavan Kannan
- Institut für Pharmazie, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale) and Physik-Department T38, Technische Universität München, 85747 Garching, Germany
| | - Martin Zacharias
- Institut für Pharmazie, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle (Saale) and Physik-Department T38, Technische Universität München, 85747 Garching, Germany
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25
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Amiri AR, Macgregor RB. The effect of hydrostatic pressure on the thermal stability of DNA hairpins. Biophys Chem 2011; 156:88-95. [DOI: 10.1016/j.bpc.2011.02.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 02/02/2011] [Accepted: 02/08/2011] [Indexed: 11/29/2022]
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26
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Reymond C, Lévesque D, Bisaillon M, Perreault JP. Developing three-dimensional models of putative-folding intermediates of the HDV ribozyme. Structure 2011; 18:1608-16. [PMID: 21134640 DOI: 10.1016/j.str.2010.09.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 09/13/2010] [Accepted: 09/17/2010] [Indexed: 01/23/2023]
Abstract
Both the role and the interacting partners of an RNA molecule can change depending on its tertiary structure. Consequently, it is important to be able to accurately predict the complete folding pathway of an RNA molecule. The hepatitis delta virus (HDV) ribozyme is a small catalytic RNA with the greatest number of folding intermediates making it the model of choice with which to address this problem. The tertiary structures of the known putative intermediates along the folding pathway of the HDV ribozyme were predicted using the Macromolecular Conformations Symbolic programming (MC-Sym) software. The structures obtained by this method received physical support from Selective 2'-Hydroxyl Acylation analyzed by Primer Extension (SHAPE). The analysis of these structures elucidated several features of the HDV ribozyme. In addition, this report represents an application for MC-Sym that permits progression one step further toward the computer prediction of an RNA molecule-folding pathway.
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Affiliation(s)
- Cédric Reymond
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Québec J1H5N4, Canada
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27
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Qing G, Xiong H, Seela F, Sun T. Spatially controlled DNA nanopatterns by "click" chemistry using oligonucleotides with different anchoring sites. J Am Chem Soc 2011; 132:15228-32. [PMID: 20936845 DOI: 10.1021/ja105246b] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
DNA patterning on surfaces has broad applications in biotechnology, nanotechnology, and other fields of life science. The common patterns make use of the highly selective base pairing which might not be stable enough for further manipulations. Furthermore, the fabrication of well-defined DNA nanostructures on solid surfaces usually lacks chemical linkages to the surface. Here we report a template-free strategy based on "click" chemistry to fabricate spatially controlled DNA nanopatterns immobilized on surfaces. The self-assembly process utilizes DNA with different anchoring sites. The position of anchoring is of crucial importance for the self-assembly process of DNA and greatly influences the assembly of particular DNA nanopatterns. It is shown that the anchoring site in a central position generates tunable nanonetworks with high regularity, compared to DNAs containing anchoring sites at terminal and other positions. The prepared patterns may find applications in DNA capturing and formation of pores and channels and can serve as templates for the patterning using other molecules.
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Affiliation(s)
- Guangyan Qing
- State Key Laboratory of Advanced Technology for Materials Synthesis and Composite, Wuhan University of Technology, Wuhan 430070, China
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28
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Acosta-Silva C, Branchadell V, Bertran J, Oliva A. Mutual relationship between stacking and hydrogen bonding in DNA. Theoretical study of guanine-cytosine, guanine-5-methylcytosine, and their dimers. J Phys Chem B 2010; 114:10217-27. [PMID: 20684646 DOI: 10.1021/jp103850h] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The mutual relationship between stacking and hydrogen-bonding and the possible influence of stacking in the different behavior of cytosine (C) and 5-methylcytosine (C') in DNA have been studied through complete DFT optimization of different structures of G-C and G-C' dimers (i.e., G-C/C-G and G-C'/C'-G), using four different functionals. Our results show that stacking leads to an increase of the O(6)...H-N(4) hydrogen bond length and to a simultaneous decrease of the N(2)-H...O(2) one, in such a way that both lengths approach each other and, in some cases, an inversion occurs. These results suggest that stacking can be a factor to explain the disparity between theory and experiment on the relative strength of the two lateral hydrogen bonds. Regarding the difference between cytosine and 5-methylcytosine, we have shown that methylation enhances the stacking interactions, mainly due to the increase of polarizability. Methylation also favors the existence of slid structures which can produce local distortions of DNA.
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Affiliation(s)
- Carles Acosta-Silva
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra 08193 Spain
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29
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Nakano SI, Oka H, Uotani Y, Uenishi K, Fujii M, Sugimoto N. Stacking interaction in the middle and at the end of a DNA helix studied with non-natural nucleotides. MOLECULAR BIOSYSTEMS 2010; 6:2023-9. [PMID: 20694257 DOI: 10.1039/c0mb00002g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Base stacking is important for the base pair interaction of a DNA duplex, DNA replication by polymerases, and single-stranded nucleotide overhangs. To study the mechanisms responsible for DNA stacking interactions, we measured the thermal stability of DNA duplexes containing a non-natural nucleotide tethered to a simple aromatic hydrocarbon group devoid of dipole moments and hydrogen bonding sites. The duplexes containing tetrahydrofuran were paired with a deoxyadenosine derivative (A/T base pair analog) or a deoxycytidine derivative (C/G base pair analog) and showed a lower stability than Watson-Crick base pairing, partly due to the loss of interbase hydrogen bonds. Conversely, non-natural nucleotides present at a dangling end yielded an interaction energy as high as that observed with base pairing. Importantly, the non-natural nucleotides yielded an interaction energy with a linear correlation similar to that of the analogous Watson-Crick base pairs both in the middle and at the end of a DNA duplex, although a different stacking mechanism between the middle and the end was suggested. Moreover, a positive cooperativity was observed in dangling end stacking of the nucleotide base moiety and aromatic hydrocarbon group. These observations are useful to understand nucleic acid interactions and to design new non-natural nucleotides.
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Affiliation(s)
- Shu-ichi Nakano
- Faculty of Frontiers of Innovative Research in Science and Technology, Konan University, 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan.
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30
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Siegfried NA, Kierzek R, Bevilacqua PC. Role of unsatisfied hydrogen bond acceptors in RNA energetics and specificity. J Am Chem Soc 2010; 132:5342-4. [PMID: 20345162 DOI: 10.1021/ja9107726] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RNA plays essential roles in much of biology. These functions are dictated by structures mediated by hydrogen bonding, stacking, electrostatics, and steric interactions. Roles of unsatisfied hydrogen bond functionalities in these structures are less well understood. Herein, we evaluated the energetic contributions of unsatisfied hydrogen bonding groups by placing chemically modified substituents in select internal positions in RNA helices and conducting thermodynamic studies. We find that unsatisfied carbonyl groups make exceptional contributions to structure formation (approximately 3 kcal/mol in free energy), most likely due to a combination of strain and dehydration effects. Thus, unsatisfied hydrogen bonding groups are likely key determinants in the folding energetics and specificity of many RNA and DNA molecules and may be especially important in tertiary structure interactions.
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Affiliation(s)
- Nathan A Siegfried
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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31
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Reymond C, Beaudoin JD, Perreault JP. Modulating RNA structure and catalysis: lessons from small cleaving ribozymes. Cell Mol Life Sci 2009; 66:3937-50. [PMID: 19718544 PMCID: PMC2777235 DOI: 10.1007/s00018-009-0124-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 07/30/2009] [Accepted: 07/31/2009] [Indexed: 01/12/2023]
Abstract
RNA is a key molecule in life, and comprehending its structure/function relationships is a crucial step towards a more complete understanding of molecular biology. Even though most of the information required for their correct folding is contained in their primary sequences, we are as yet unable to accurately predict both the folding pathways and active tertiary structures of RNA species. Ribozymes are interesting molecules to study when addressing these questions because any modifications in their structures are often reflected in their catalytic properties. The recent progress in the study of the structures, the folding pathways and the modulation of the small ribozymes derived from natural, self-cleaving, RNA motifs have significantly contributed to today's knowledge in the field.
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Affiliation(s)
- Cedric Reymond
- RNA Group/Groupe ARN, Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4 Canada
| | - Jean-Denis Beaudoin
- RNA Group/Groupe ARN, Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4 Canada
| | - Jean-Pierre Perreault
- RNA Group/Groupe ARN, Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1H 5N4 Canada
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32
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Nwe K, Andolina CM, Huang CH, Morrow JR. PARACEST properties of a dinuclear neodymium(III) complex bound to DNA or carbonate. Bioconjug Chem 2009; 20:1375-82. [PMID: 19555071 DOI: 10.1021/bc900146z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A dinuclear Nd(III) macrocyclic complex of 1 (1,4-bis[1-(4,7,10-tris(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane]-p-xylene) and mononuclear complexes of 1,4,7-tris-1,4,7,10-tetraazacyclododecane, 2, and 1,4,7-tris[(N-N-diethyl)carbamoylmethyl]-1,4,7,10-tetraazacyclododecane, 3, are prepared. Complexes of 1 and 2 give rise to a PARACEST (paramagnetic chemical exchange saturation transfer) peak from exchangeable amide protons that resonate approximately 12 ppm downfield from the bulk water proton resonance. The dinuclear Nd(III) complex is promising as a PARACEST contrast agent for MRI applications, because it has an optimal pH of 7.5 and the rate constant for amide proton exchange (2700 s(-1)) is nearly as large as it can be within slow exchange conditions with bulk water. Dinuclear Ln(2)(1) complexes (Ln(III) = Nd(III), Eu(III)) bind tightly to anionic ligands including carbonate, diethyl phosphate, and DNA. The CEST amide peak of Nd(2)(1) is enhanced by certain DNA sequences that contain hairpin loops, but decreases in the presence of diethyl phosphate or carbonate. Direct excitation luminescence studies of Eu(2)(1) show that double-stranded and hairpin-loop DNA sequences displace one water ligand on each Eu(III) center. DNA displaces carbonate ion despite the low dissociation constant for the Eu(2)(1) carbonate complex (K(d) = 15 microM). Enhancement of the CEST effect of a lanthanide complex by binding to DNA is a promising step toward the preparation of PARACEST agents containing DNA scaffolds.
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Affiliation(s)
- Kido Nwe
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260, USA
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33
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Blose JM, Lloyd KP, Bevilacqua PC. Portability of the GN(R)A Hairpin Loop Motif between RNA and DNA. Biochemistry 2009; 48:8787-94. [DOI: 10.1021/bi901038s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Joshua M. Blose
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
- Present Address: School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853
| | - Kenneth P. Lloyd
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts, Worcester, Massachusetts 01605
| | - Philip C. Bevilacqua
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802
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34
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Blose JM, Proctor DJ, Veeraraghavan N, Misra VK, Bevilacqua PC. Contribution of the closing base pair to exceptional stability in RNA tetraloops: roles for molecular mimicry and electrostatic factors. J Am Chem Soc 2009; 131:8474-84. [PMID: 19476351 DOI: 10.1021/ja900065e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hairpins are common RNA secondary structures that play multiple roles in nature. Tetraloops are the most frequent RNA hairpin loops and are often phylogenetically conserved. For both the UNCG and GNRA families, CG closing base pairs (cbps) confer exceptional thermodynamic stability but the molecular basis for this has remained unclear. We propose that, despite having very different overall folds, these two tetraloop families achieve stability by presenting the same functionalities to the major groove edge of the CG cbp. Thermodynamic contributions of this molecular mimicry were investigated using substitutions at the nucleobase and functional group levels. By either interrupting or deleting loop-cbp electrostatic interactions, which were identified by solving the nonlinear Poisson-Boltzmann (NLPB) equation, stability changed in a manner consistent with molecular mimicry. We also observed a linear relationship between DeltaG(o)(37) and log[Na(+)] for both families, and loops with a CG cbp had a decreased dependence of stability on salt. NLPB calculations revealed that, for both UUCG and GAAA tetraloops, the GC cbp form has a higher surface charge density, although it arises from changes in loop compaction for UUCG and changes in loop configuration for GAAA. Higher surface charge density leads to stronger interactions of GC cbp loops with solvent and salt, which explains the correlation between experimental and calculated trends of free energy with salt. Molecular mimicry as evidenced in these two stable but otherwise unrelated tetraloops may underlie common functional roles in other RNA and DNA motifs.
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Affiliation(s)
- Joshua M Blose
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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35
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Gil A, Branchadell V, Bertran J, Oliva A. An analysis of the different behavior of DNA and RNA through the study of the mutual relationship between stacking and hydrogen bonding. J Phys Chem B 2009; 113:4907-14. [PMID: 19284733 DOI: 10.1021/jp809737c] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The mutual relationship between stacking and hydrogen bonding and the possible influence of stacking in the different behavior of DNA and RNA base pairs have been studied through complete DFT optimization of different structures of A-U and A-T dimers (i.e., A-U/U-A and A-T/T-A), using some functionals developed by the group of Truhlar. The results obtained in this work clearly show that stacking and hydrogen bonding are deeply connected. The different behavior of DNA and RNA when replacing uracil by thymine can be interpreted through the formation of a stabilizing CH/pi interaction between the methyl group of thymine and the five-member ring of adenine.
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Affiliation(s)
- Adrià Gil
- Departament de Quimica, Universitat Autonoma de Barcelona, Bellaterra 08193, Spain
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36
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Siegfried NA, Bevilacqua PC. Thinking inside the box: designing, implementing, and interpreting thermodynamic cycles to dissect cooperativity in RNA and DNA folding. Methods Enzymol 2009; 455:365-93. [PMID: 19289213 DOI: 10.1016/s0076-6879(08)04213-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Double and triple mutant thermodynamic cycles provide a means to dissect the cooperativity of RNA and DNA folding at both the secondary and tertiary structural levels through use of the thermodynamic box or cube. In this article, we describe three steps for applying thermodynamic cycles to nucleic acid folding, with considerations of both conceptual and experimental features. The first step is design of an appropriate system and development of hypotheses regarding which residues might interact. Next is implementing this design in terms of a tractable experimental strategy, with an emphasis on UV melting. The final step, and the one we emphasize the most, is interpreting mutant cycles in terms of coupling between specific residues in the RNA or DNA. Coupling free energy in the absence and presence of changes elsewhere in the molecule is discussed in terms of specific folding models, including stepwise folding and concerted changes. Last, we provide a practical section on the use of commercially available software (KaleidaGraph) to fit melting data, along with a consideration of error propagation. Along the way, specific examples are chosen from the literature to illustrate the methods. This article is intended to be accessible to the biochemist or biologist without extensive thermodynamics background.
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Affiliation(s)
- Nathan A Siegfried
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, USA
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37
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Chen JH, Gong B, Bevilacqua PC, Carey PR, Golden BL. A catalytic metal ion interacts with the cleavage Site G.U wobble in the HDV ribozyme. Biochemistry 2009; 48:1498-507. [PMID: 19178151 DOI: 10.1021/bi8020108] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The HDV ribozyme self-cleaves by a chemical mechanism involving general acid-base catalysis to generate 2',3'-cyclic phosphate and 5'-hydroxyl termini. Biochemical studies from several laboratories have implicated C75 as the general acid and hydrated magnesium as the general base. We have previously shown that C75 has a pK(a) shifted >2 pH units toward neutrality [Gong, B., Chen, J. H., Chase, E., Chadalavada, D. M., Yajima, R., Golden, B. L., Bevilacqua, P. C., and Carey, P. R. (2007) J. Am. Chem. Soc. 129, 13335-13342], while in crystal structures, it is well-positioned for proton transfer. However, no evidence for a hydrated magnesium poised to serve as a general base in the reaction has been observed in high-resolution crystal structures of various reaction states and mutants. Herein, we use solution kinetic experiments and parallel Raman crystallographic studies to examine the effects of pH on the rate and Mg(2+) binding properties of wild-type and 7-deazaguanosine mutants of the HDV ribozyme. These data suggest that a previously unobserved hydrated magnesium ion interacts with N7 of the cleavage site G.U wobble base pair. Integrating this metal ion binding site with the available crystal structures provides a new three-dimensional model for the active site of the ribozyme that accommodates all available biochemical data and appears competent for catalysis. The position of this metal is consistent with a role of a magnesium-bound hydroxide as a general base as dictated by biochemical data.
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Affiliation(s)
- Jui-Hui Chen
- Department of Biochemistry, Purdue University, 175 South University Street, West Lafayette, Indiana 47907, USA
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38
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Antony J, Brüske B, Grimme S. Cooperativity in noncovalent interactions of biologically relevant molecules. Phys Chem Chem Phys 2009; 11:8440-7. [PMID: 19774274 DOI: 10.1039/b907260h] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Jens Antony
- Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, D-48149 Münster, Germany
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39
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Touboul D, Zenobi R. A simple model for exploring conformation of highly-charged electrosprayed single-stranded oligonucleotides. Chem Commun (Camb) 2008:298-300. [PMID: 19209308 DOI: 10.1039/b816801f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study of the maximum charge state versus the molecular weight of single-stranded polynucleotides analyzed by electrospray reveals that single strands adopt a compact conformation in positive ion mode, whereas linear structures are predominant in negative ion mode.
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Affiliation(s)
- David Touboul
- Department of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich, Switzerland
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40
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Bevilacqua PC, Blose JM. Structures, kinetics, thermodynamics, and biological functions of RNA hairpins. Annu Rev Phys Chem 2008; 59:79-103. [PMID: 17937599 DOI: 10.1146/annurev.physchem.59.032607.093743] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Most RNA comprises one strand and therefore can fold back on itself to form complex structures. At the heart of these structures is the hairpin, which is composed of a stem having Watson-Crick base pairing and a loop wherein the backbone changes directionality. First, we review the structure of hairpins including diversity in the stem, loop, and closing base pair. The function of RNA hairpins in biology is discussed next, including roles for isolated hairpins, as well as hairpins in the context of complex tertiary structures. We describe the kinetics and thermodynamics of hairpin folding including models for hairpin folding, folding transition states, and the cooperativity of folding. Lastly, we discuss some ways in which hairpins can influence the folding and function of tertiary structures, both directly and indirectly. RNA hairpins provide a simple means of controlling gene expression that can be understood in the language of physical chemistry.
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Affiliation(s)
- Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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41
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Wang Y, Ng MTT, Zhou T, Li X, Tan CH, Li T. C3-Spacer-containing circular oligonucleotides as inhibitors of human topoisomerase I. Bioorg Med Chem Lett 2008; 18:3597-602. [PMID: 18490159 DOI: 10.1016/j.bmcl.2008.04.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2008] [Revised: 04/25/2008] [Accepted: 04/30/2008] [Indexed: 11/18/2022]
Abstract
Some dumbbell-shaped circular oligonucleotides containing internal C3-spacers and Topo I-binding sites were designed and synthesized which displayed high inhibitory efficiency on the activity of human Topo I as well as resisted the degradation by some DNA repair enzymes.
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Affiliation(s)
- Yifan Wang
- Department of Chemistry, 3 Science Drive 3, National University of Singapore, Singapore 117543, Singapore
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42
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Chauhan S, Woodson SA. Tertiary interactions determine the accuracy of RNA folding. J Am Chem Soc 2008; 130:1296-303. [PMID: 18179212 DOI: 10.1021/ja076166i] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
RNAs must fold into unique three-dimensional structures to function in the cell, but how each polynucleotide finds its native structure is not understood. To investigate whether the stability of the tertiary structure determines the speed and accuracy of RNA folding, docking of a tetraloop with its receptor in a bacterial group I ribozyme was perturbed by site-directed mutagenesis. Disruption of the tetraloop or its receptor destabilizes tertiary interactions throughout the ribozyme by 2-3 kcal/mol, demonstrating that tertiary interactions form cooperatively in the transition from a native-like intermediate to the native state. Nondenaturing PAGE and RNase T1 digestion showed that base pairs form less homogeneously in the mutant RNAs during the transition from the unfolded state to the intermediate. Thus, tertiary interactions between helices bias the ensemble of secondary structures toward native-like conformations. Time-resolved hydroxyl radical footprinting showed that the wild-type ribozyme folds completely within 5-20 ms. By contrast, only 40-60% of a tetraloop mutant ribozyme folds in 30-40 ms, with the remainder folding in 30-200 s via nonnative intermediates. Therefore, destabilization of tetraloop-receptor docking introduces an alternate folding pathway in the otherwise smooth energy landscape of the wild-type ribozyme. Our results show that stable tertiary structure increases the flux through folding pathways that lead directly and rapidly to the native structure.
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Affiliation(s)
- Seema Chauhan
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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43
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Kuznetsov SV, Ren CC, Woodson SA, Ansari A. Loop dependence of the stability and dynamics of nucleic acid hairpins. Nucleic Acids Res 2007; 36:1098-112. [PMID: 18096625 PMCID: PMC2275088 DOI: 10.1093/nar/gkm1083] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hairpin loops are critical to the formation of nucleic acid secondary structure, and to their function. Previous studies revealed a steep dependence of single-stranded DNA (ssDNA) hairpin stability with length of the loop (L) as approximately L(8.5 +/- 0.5), in 100 mM NaCl, which was attributed to intraloop stacking interactions. In this article, the loop-size dependence of RNA hairpin stabilities and their folding/unfolding kinetics were monitored with laser temperature-jump spectroscopy. Our results suggest that similar mechanisms stabilize small ssDNA and RNA loops, and show that salt contributes significantly to the dependence of hairpin stability on loop size. In 2.5 mM MgCl2, the stabilities of both ssDNA and RNA hairpins scale as approximately L(4 +/- 0.5), indicating that the intraloop interactions are weaker in the presence of Mg2+. Interestingly, the folding times for ssDNA hairpins (in 100 mM NaCl) and RNA hairpins (in 2.5 mM MgCl2) are similar despite differences in the salt conditions and the stem sequence, and increase similarly with loop size, approximately L(2.2 +/- 0.5) and approximately L(2.6 +/- 0.5), respectively. These results suggest that hairpins with small loops may be specifically stabilized by interactions of the Na+ ions with the loops. The results also reinforce the idea that folding times are dominated by an entropic search for the correct nucleating conformation.
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Affiliation(s)
- Serguei V Kuznetsov
- Department of Physics (M/C 273), University of Illinois at Chicago, 845 W. Taylor St., Chicago, IL 60607, USA
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44
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Kannan S, Zacharias M. Folding of a DNA hairpin loop structure in explicit solvent using replica-exchange molecular dynamics simulations. Biophys J 2007; 93:3218-28. [PMID: 17660316 PMCID: PMC2025651 DOI: 10.1529/biophysj.107.108019] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hairpin loop structures are common motifs in folded nucleic acids. The 5'-GCGCAGC sequence in DNA forms a characteristic and stable trinucleotide hairpin loop flanked by a two basepair stem helix. To better understand the structure formation of this hairpin loop motif in atomic detail, we employed replica-exchange molecular dynamics (RexMD) simulations starting from a single-stranded DNA conformation. In two independent 36 ns RexMD simulations, conformations in very close agreement with the experimental hairpin structure were sampled as dominant conformations (lowest free energy state) during the final phase of the RexMDs ( approximately 35% at the lowest temperature replica). Simultaneous compaction and accumulation of folded structures were observed. Comparison of the GCA trinucleotides from early stages of the simulations with the folded topology indicated a variety of central loop conformations, but arrangements close to experiment that are sampled before the fully folded structure also appeared. Most of these intermediates included a stacking of the C(2) and G(3) bases, which was further stabilized by hydrogen bonding to the A(5) base and a strongly bound water molecule bridging the C(2) and A(5) in the DNA minor groove. The simulations suggest a folding mechanism where these intermediates can rapidly proceed toward the fully folded hairpin and emphasize the importance of loop and stem nucleotide interactions for hairpin folding. In one simulation, a loop motif with G(3) in syn conformation (dihedral flip at N-glycosidic bond) accumulated, resulting in a misfolded hairpin. Such conformations may correspond to long-lived trapped states that have been postulated to account for the folding kinetics of nucleic acid hairpins that are slower than expected for a semiflexible polymer of the same size.
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45
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Balkwill GD, Williams HEL, Searle MS. Structure and folding dynamics of a DNA hairpin with a stabilising d(GNA) trinucleotide loop: influence of base pair mis-matches and point mutations on conformational equilibria. Org Biomol Chem 2007; 5:832-9. [PMID: 17315071 DOI: 10.1039/b616820e] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hairpins are known to play specific roles in DNA- and RNA--protein recognition. Various disease states are thought to originate from the ill-timed formation of a hairpin loop during transcription, particularly in the context of triplet repeats which are associated with myotonic dystrophy, fragile X syndrome and other genetic disorders. An understanding of nucleic acid folding mechanisms requires a detailed appreciation of the timescales of these local folding events, a characterisation of the conformational equilibria that exist in solution and the influence of point mutations on the relative stabilities of the different species. We investigate using NMR and CD spectroscopy the structure and dynamics of a DNA hairpin containing a highly stabilising cGNAg loop. The single-stranded 13-mer 5'-d(GCTACGNAGTCGC) with N = T folds to form a hairpin structure which accommodates a C-T mis-matched base pair within the double-stranded stem region. The hairpin is in equilibrium with a double-stranded duplex form with the mixture of two interconverting conformations in slow exchange on the NMR timescale (1-2 s(-1) at 308 K). We are able to characterise the dynamics of the interconversion process by NMR magnetisation transfer and by CD stopped-flow kinetic experiments. The latter shows that the hairpin folds too rapidly to detect by this method (>500 s(-1)) and forms in a "kinetic overshoot" followed by a much slower equilibration to a mixture of conformations ( approximately 0.13 s(-1) at 298 K). A point mutation that converts the GTA to a GAA loop sequence destabilises the intermolecular duplex structure and enables us to unambiguously assign the various dynamic processes that are taking place.
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Affiliation(s)
- Graham D Balkwill
- Centre for Biomolecular Sciences, School of Chemistry, University Park, Nottingham, NG7 2RD, UK.
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46
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Cornish PV, Giedroc DP. Pairwise coupling analysis of helical junction hydrogen bonding interactions in luteoviral RNA pseudoknots. Biochemistry 2006; 45:11162-71. [PMID: 16964977 PMCID: PMC2573051 DOI: 10.1021/bi060430n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A 28-nucleotide mRNA pseudoknot that overlaps the P1 and P2 genes of sugarcane yellow leaf virus (ScYLV) stimulates -1 ribosomal frameshifting. The in vitro frameshifting efficiency is decreased >or=8-fold upon substitution of the 3'-most loop 2 nucleotide (C27) with adenosine, which accepts a hydrogen bond from the 2'-OH group of C14 in stem S1. The solution structures of the wild-type (WT) and C27A ScYLV RNA pseudoknots show that while the RNAs adopt virtually identical overall structures, there are significant structural differences at the helical junctions of the two RNAs. Specifically, C8(+) in loop L1 in the C8(+).(G12.C28) L1-S2 major groove base triple is displaced by approximately 2.3 A relative to the accepting stem 2 base pair (G12.C28) in the C27A RNA. Here, we use a double mutant cycle approach to analyze the pairwise coupling of the C8(+).(G12.C28)...C27.(C14-G7) and ...A27.(C14-G7) hydrogen bonds in the WT and C27A ScYLV RNAs, respectively, and compare these findings with previous results from the beet western yellows virus (BWYV) RNA. We find that the pairwise coupling free energy (delta(AB)(i)) is favorable for the WT RNA (-0.7 +/- 0.1 kcal/mol), thus revealing that formation of these two hydrogen bonds is positively cooperative. In contrast, delta(AB)(i) is 0.9 +/- 0.4 kcal/mol for the poorly functional C27A ScYLV RNA, indicative of nonadditive hydrogen bond formation. These results reveal that cooperative hydrogen bond formation across the helical stem junction in H-type pseudoknots correlates with enhanced frameshift stimulation by luteoviral mRNA pseudoknots.
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Affiliation(s)
| | - David P. Giedroc
- To whom correspondence should be addressed: Phone: 979-845-4231; Fax: 979-845-4946;
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47
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Nakano SI, Uotani Y, Uenishi K, Fujii M, Sugimoto N. DNA base flipping by a base pair-mimic nucleoside. Nucleic Acids Res 2005; 33:7111-9. [PMID: 16361269 PMCID: PMC1316115 DOI: 10.1093/nar/gki1018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
On the basis of non-covalent bond interactions in nucleic acids, we synthesized the deoxyadenosine derivatives tethering a phenyl group (X) and a naphthyl group (Z) by an amide linker, which mimic a Watson–Crick base pair. Circular dichroism spectra indicated that the duplexes containing X and Z formed a similar conformation regardless of the opposite nucleotide species (A, G, C, T and an abasic site analogue F), which was not observed for the natural duplexes. The ΔG370 values among the natural duplexes containing the A/A, A/G, A/C, A/T and A/F pairs differed by 5.2 kcal mol−1 while that among the duplexes containing X or Z in place of the adenine differed by only 1.9 or 2.8 kcal mol−1, respectively. Fluorescence quenching experiments confirmed that 2-amino purine opposite X adopted an unstacked conformation. The structural and thermodynamic analyses suggest that the aromatic hydrocarbon group of X and Z intercalates into a double helix, resulting in the opposite nucleotide base flipping into an unstacked position regardless of the nucleotide species. This observation implies that modifications at the aromatic hydrocarbon group and the amide linker may expand the application of the base pair-mimic nucleosides for molecular biology and biotechnology.
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Affiliation(s)
- Shu-ichi Nakano
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Yuuki Uotani
- Department of Chemistry, Faculty of Science and Engineering, Konan University8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
| | - Kazuya Uenishi
- Molecular Engineering Institute, Kinki University11-6 Kayanomori, Iizuka, Fukuoka 820-8555, Japan
| | - Masayuki Fujii
- Molecular Engineering Institute, Kinki University11-6 Kayanomori, Iizuka, Fukuoka 820-8555, Japan
- Department of Environmental and Biological Chemistry, Kinki University11-6 Kayanomori, Iizuka, Fukuoka 820-8555, Japan
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
- Department of Chemistry, Faculty of Science and Engineering, Konan University8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
- To whom correspondence should be addressed. Tel: +81 78 435 2497; Fax: +81 78 435 2539;
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48
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Watkins NE, SantaLucia J. Nearest-neighbor thermodynamics of deoxyinosine pairs in DNA duplexes. Nucleic Acids Res 2005; 33:6258-67. [PMID: 16264087 PMCID: PMC1277807 DOI: 10.1093/nar/gki918] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Revised: 10/04/2005] [Accepted: 10/04/2005] [Indexed: 11/18/2022] Open
Abstract
Nearest-neighbor thermodynamic parameters of the 'universal pairing base' deoxyinosine were determined for the pairs I.C, I.A, I.T, I.G and I.I adjacent to G.C and A.T pairs. Ultraviolet absorbance melting curves were measured and non-linear regression performed on 84 oligonucleotide duplexes with 9 or 12 bp lengths. These data were combined with data for 13 inosine containing duplexes from the literature. Multiple linear regression was used to solve for the 32 nearest-neighbor unknowns. The parameters predict the T(m) for all sequences within 1.2 degrees C on average. The general trend in decreasing stability is I.C > I.A > I.T approximately I. G > I.I. The stability trend for the base pair 5' of the I.X pair is G.C > C.G > A.T > T.A. The stability trend for the base pair 3' of I.X is the same. These trends indicate a complex interplay between H-bonding, nearest-neighbor stacking, and mismatch geometry. A survey of 14 tandem inosine pairs and 8 tandem self-complementary inosine pairs is also provided. These results may be used in the design of degenerate PCR primers and for degenerate microarray probes.
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Affiliation(s)
- Norman E. Watkins
- Department of Chemistry, Wayne State UniversityDetroit, MI 48202, USA
| | - John SantaLucia
- Department of Chemistry, Wayne State UniversityDetroit, MI 48202, USA
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49
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Nakano SI, Sugimoto N. Central Dogma for a Molecular Design Based on DNA: DNB (Databasing/Designable Nanobio) → ENB (Engineering Nanobio) → FNB (Functional Nanobio). CHEM LETT 2005. [DOI: 10.1246/cl.2005.1206] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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50
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Nelson KE, Bruesehoff PJ, Lu Y. In Vitro Selection of High Temperature Zn2+-Dependent DNAzymes. J Mol Evol 2005; 61:216-25. [PMID: 16096680 DOI: 10.1007/s00239-004-0374-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2004] [Accepted: 03/28/2005] [Indexed: 10/25/2022]
Abstract
In vitro selection of Zn(2+)-dependent RNA-cleaving DNAzymes with activity at 90 degrees C has yielded a diverse spool of selected sequences. The RNA cleavage efficiency was found in all cases to be specific for Zn(2+) over Pb(2+), Ca(2+), Cd(2+), Co(2+), Hg(2+), and Mg(2+). The Zn(2+)-dependent activity assay of the most active sequence showed that the DNAzyme possesses an apparent Zn(2+)-binding dissociation constant of 234 muM and that its activity increases with increasing temperatures from 50-90 degrees C. A fit of the Arrhenius plot data gave E(a) = 15.3 kcal mol(-1). Surprisingly, the selected Zn(2+)-dependent DNAzymes showed only a modest (approximately 3-fold) activity enhancement over the background rate of cleavage of random sequences containing a single embedded ribonucleotide within an otherwise DNA oligonucleotide. The result is attributable to the ability of DNA to sustain cleavage activity at high temperature with minimal secondary structure when Zn(2+) is present. Since this effect is highly specific for Zn(2+), this metal ion may play a special role in molecular evolution of nucleic acids at high temperature.
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Affiliation(s)
- Kevin E Nelson
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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