401
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Laos R, Thomson JM, Benner SA. DNA polymerases engineered by directed evolution to incorporate non-standard nucleotides. Front Microbiol 2014; 5:565. [PMID: 25400626 PMCID: PMC4215692 DOI: 10.3389/fmicb.2014.00565] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 10/07/2014] [Indexed: 11/13/2022] Open
Abstract
DNA polymerases have evolved for billions of years to accept natural nucleoside triphosphate substrates with high fidelity and to exclude closely related structures, such as the analogous ribonucleoside triphosphates. However, polymerases that can accept unnatural nucleoside triphosphates are desired for many applications in biotechnology. The focus of this review is on non-standard nucleotides that expand the genetic "alphabet." This review focuses on experiments that, by directed evolution, have created variants of DNA polymerases that are better able to accept unnatural nucleotides. In many cases, an analysis of past evolution of these polymerases (as inferred by examining multiple sequence alignments) can help explain some of the mutations delivered by directed evolution.
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Affiliation(s)
- Roberto Laos
- Foundation for Applied Molecular Evolution Gainesville, FL, USA
| | | | - Steven A Benner
- Foundation for Applied Molecular Evolution Gainesville, FL, USA
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402
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Cafferty BJ, Hud NV. Abiotic synthesis of RNA in water: a common goal of prebiotic chemistry and bottom-up synthetic biology. Curr Opin Chem Biol 2014; 22:146-57. [PMID: 25438801 DOI: 10.1016/j.cbpa.2014.09.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 09/13/2014] [Indexed: 01/01/2023]
Abstract
For more than half a century chemists have searched for a plausible prebiotic synthesis of RNA. The initial advances of the 1960s and 1970s were followed by decades of measured progress and a growing pessimism about overcoming remaining challenges. Fortunately, the past few years have provided a number of important advances, including new abiotic routes for the synthesis of nucleobases, nucleosides, and nucleotides. Recent discoveries also provide additional support for the hypothesis that RNA is the product of evolution, being preceded by ancestral genetic polymers, or pre-RNAs, that are synthesized more easily than RNA. In some cases, parallel searches for plausible prebiotic routes to RNA and pre-RNAs have provided more than one experimentally verified synthesis of RNA substructures and possible predecessors. Just as the synthesis of a contemporary biological molecule cannot be understood without knowledge of cellular metabolism, it is likely that an integrated approach that takes into account both plausible prebiotic reactions and plausible prebiotic environments will ultimately provide the most satisfactory and unifying chemical scenarios for the origin of nucleic acids. In this context, recent advances towards the abiotic synthesis of RNA and candidates for pre-RNAs are beginning to suggest that some molecules (e.g., urea) were multi-faceted contributors to the origin of nucleic acids, and the origin of life.
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Affiliation(s)
- Brian J Cafferty
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Nicholas V Hud
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA.
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403
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Hagiwara K, Fujita H, Kasahara Y, Irisawa Y, Obika S, Kuwahara M. In vitro selection of DNA-based aptamers that exhibit RNA-like conformations using a chimeric oligonucleotide library that contains two different xeno-nucleic acids. MOLECULAR BIOSYSTEMS 2014; 11:71-6. [PMID: 25325213 DOI: 10.1039/c4mb00436a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We successfully generated chimeric DNA aptamers that contained six nucleoside analogs of 2'-O,4'-C-methylene bridged/locked nucleic acid (2',4'-BNA/LNA) in the primer region and multiple guanosine analogs of 2'-deoxy-2'-fluoro-ribonucleic acid (FNA) in the non-primer region using capillary electrophoresis-systematic evolution of ligands by exponential enrichment (CE-SELEX). Active species enrichment became saturated only after five selection rounds, and we obtained DNA-based xeno-nucleic acid (XNA) aptamers that had high binding affinities for the target human thrombin, with dissociation constant (Kd) values of ≥10 nanomolar. Based on sequence and circular dichroism (CD) analyses, these XNA aptamers exhibited RNA-like conformations, which could cause DNA-based strands to adopt structurally diverse conformations.
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Affiliation(s)
- Kenta Hagiwara
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
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404
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Nucleic Acid Ligands With Protein-like Side Chains: Modified Aptamers and Their Use as Diagnostic and Therapeutic Agents. MOLECULAR THERAPY-NUCLEIC ACIDS 2014; 3:e201. [PMID: 25291143 PMCID: PMC4217074 DOI: 10.1038/mtna.2014.49] [Citation(s) in RCA: 347] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/12/2014] [Indexed: 12/30/2022]
Abstract
Limited chemical diversity of nucleic acid libraries has long been suspected to be a major constraining factor in the overall success of SELEX (Systematic Evolution of Ligands by EXponential enrichment). Despite this constraint, SELEX has enjoyed considerable success over the past quarter of a century as a result of the enormous size of starting libraries and conformational richness of nucleic acids. With judicious introduction of functional groups absent in natural nucleic acids, the “diversity gap” between nucleic acid–based ligands and protein-based ligands can be substantially bridged, to generate a new class of ligands that represent the best of both worlds. We have explored the effect of various functional groups at the 5-position of uracil and found that hydrophobic aromatic side chains have the most profound influence on the success rate of SELEX and allow the identification of ligands with very low dissociation rate constants (named Slow Off-rate Modified Aptamers or SOMAmers). Such modified nucleotides create unique intramolecular motifs and make direct contacts with proteins. Importantly, SOMAmers engage their protein targets with surfaces that have significantly more hydrophobic character compared with conventional aptamers, thereby increasing the range of epitopes that are available for binding. These improvements have enabled us to build a collection of SOMAmers to over 3,000 human proteins encompassing major families such as growth factors, cytokines, enzymes, hormones, and receptors, with additional SOMAmers aimed at pathogen and rodent proteins. Such a large and growing collection of exquisite affinity reagents expands the scope of possible applications in diagnostics and therapeutics.
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405
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Towards applications of synthetic genetic polymers in diagnosis and therapy. Curr Opin Chem Biol 2014; 22:79-84. [PMID: 25285754 DOI: 10.1016/j.cbpa.2014.09.022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/18/2014] [Accepted: 09/18/2014] [Indexed: 02/05/2023]
Abstract
Aptamers are a class of single-stranded nucleic acid ligands that can bind their targets with high specificity and affinities rivalling those of antibodies. First described over 20 years ago by Tuerk & Gold [1] and Ellington & Szostak [2] (who coined the name), their promise as both diagnostic and therapeutic agents remains to be realised. Key problems include the generally low biostability of the standard DNA/RNA or mixed RNA/2'F-DNA backbones under physiological conditions, limited chemical diversity of functional groups on the natural nucleobases, and the difficulty in reliably discovering aptamer ligands to some therapeutic targets. This review will describe recent progress in developing aptamer selection technology as well as expanding aptamer chemistry and informational complexity to improve aptamer discovery and properties.
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406
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Brewer A, Davis AP. Chiral encoding may provide a simple solution to the origin of life. Nat Chem 2014; 6:569-74. [PMID: 24950314 DOI: 10.1038/nchem.1981] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 05/14/2014] [Indexed: 11/09/2022]
Abstract
The route by which the complex and specific molecules of life arose from the 'prebiotic soup' remains an unsolved problem. Evolution provides a large part of the answer, but this requires molecules that can carry information (that is, exist in many variants) and can replicate themselves. The process is commonplace in living organisms, but not so easy to achieve with simple chemical systems. It is especially difficult to contemplate in the chemical chaos of the prebiotic world. Although popular in many quarters, the notion that RNA was the first self-replicator carries many difficulties. Here, we present an alternative view, suggesting that there may be undiscovered self-replication mechanisms possible in much simpler systems. In particular, we highlight the possibility of information coding through stereochemical configurations of substituents in organic polymers. We also show that this coding system leads naturally to enantiopurity, solving the apparent problem of biological homochirality.
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Affiliation(s)
- Ashley Brewer
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Anthony P Davis
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
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407
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He S, Zhao H, Guo X, Xu X, Zhou X, Liu J, Xing Z, Ye L, Jiang L, Chen Q, He Y. The Readout of Base-Pair Information in Adenine-Thymine α-D-Arabinonucleosides. Chemistry 2014; 20:15473-81. [DOI: 10.1002/chem.201403998] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Indexed: 11/10/2022]
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408
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Breaker RR, Joyce GF. The expanding view of RNA and DNA function. CHEMISTRY & BIOLOGY 2014; 21:1059-65. [PMID: 25237854 PMCID: PMC4171699 DOI: 10.1016/j.chembiol.2014.07.008] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 07/16/2014] [Accepted: 07/21/2014] [Indexed: 11/28/2022]
Abstract
RNA and DNA are simple linear polymers consisting of only four major types of subunits, and yet these molecules carry out a remarkable diversity of functions in cells and in the laboratory. Each newly discovered function of natural or engineered nucleic acids enforces the view that prior assessments of nucleic acid function were far too narrow and that many more exciting findings are yet to come. This Perspective highlights just a few of the numerous discoveries over the past 20 years pertaining to nucleic acid function, focusing on those that have been of particular interest to chemical biologists. History suggests that there will continue to be many opportunities to engage chemical biologists in the discovery, creation, and manipulation of nucleic acid function in the years to come.
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Affiliation(s)
- Ronald R Breaker
- Department of Molecular, Cellular and Developmental Biology, and Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, Box 208103, New Haven, CT 06520, USA.
| | - Gerald F Joyce
- Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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409
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Pezo V, Schepers G, Lambertucci C, Marlière P, Herdewijn P. Probing ambiguous base-pairs by genetic transformation with XNA templates. Chembiochem 2014; 15:2255-8. [PMID: 25158283 DOI: 10.1002/cbic.201402226] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Indexed: 11/11/2022]
Abstract
The templating potential of anhydrohexitol oligonucleotides bearing ambiguous bases was studied in vivo, by using a selection screen for mosaic heteroduplex plasmids in Escherichia coli. 1,5-Anhydro-2,3-dideoxy-2-(5-nitroindazol-1-yl)-D-arabino-hexitol showed the greatest ambiguity among the three nucleosides tested. At most two successive ambiguous bases could be tolerated on hexitol templates read in bacterial cells. Hexitol nucleosides bearing simplified heterocycles thus stand as promising monomers for generating random DNA sequences in vivo from defined synthetic oligonucleotides.
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Affiliation(s)
- Valérie Pezo
- CEA, DSV, IG, Genoscope, 2 rue Gaston Crémieux 91057 Evry Cedex (France); ISSB, Génopole genavenir6, Equipe Xénome, 5 rue Henri Desbruères 91030 Evry Cedex (France)
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410
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Yordanov B, Kim J, Petersen RL, Shudy A, Kulkarni VV, Phillips A. Computational design of nucleic acid feedback control circuits. ACS Synth Biol 2014; 3:600-16. [PMID: 25061797 DOI: 10.1021/sb400169s] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The design of synthetic circuits for controlling molecular-scale processes is an important goal of synthetic biology, with potential applications in future in vitro and in vivo biotechnology. In this paper, we present a computational approach for designing feedback control circuits constructed from nucleic acids. Our approach relies on an existing methodology for expressing signal processing and control circuits as biomolecular reactions. We first extend the methodology so that circuits can be expressed using just two classes of reactions: catalysis and annihilation. We then propose implementations of these reactions in three distinct classes of nucleic acid circuits, which rely on DNA strand displacement, DNA enzyme and RNA enzyme mechanisms, respectively. We use these implementations to design a Proportional Integral controller, capable of regulating the output of a system according to a given reference signal, and discuss the trade-offs between the different approaches. As a proof of principle, we implement our methodology as an extension to a DNA strand displacement software tool, thus allowing a broad range of nucleic acid circuits to be designed and analyzed within a common modeling framework.
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Affiliation(s)
| | - Jongmin Kim
- Division
of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | | | - Angelina Shudy
- Department
of Electrical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Vishwesh V. Kulkarni
- Department
of Electrical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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411
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Agustín-Pavón C, Isalan M. Synthetic biology and therapeutic strategies for the degenerating brain: Synthetic biology approaches can transform classical cell and gene therapies, to provide new cures for neurodegenerative diseases. Bioessays 2014; 36:979-90. [PMID: 25100403 PMCID: PMC4312882 DOI: 10.1002/bies.201400094] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Synthetic biology is an emerging engineering discipline that attempts to design and rewire biological components, so as to achieve new functions in a robust and predictable manner. The new tools and strategies provided by synthetic biology have the potential to improve therapeutics for neurodegenerative diseases. In particular, synthetic biology will help design small molecules, proteins, gene networks, and vectors to target disease-related genes. Ultimately, new intelligent delivery systems will provide targeted and sustained therapeutic benefits. New treatments will arise from combining ‘protect and repair’ strategies: the use of drug treatments, the promotion of neurotrophic factor synthesis, and gene targeting. Going beyond RNAi and artificial transcription factors, site-specific genome modification is likely to play an increasing role, especially with newly available gene editing tools such as CRISPR/Cas9 systems. Taken together, these advances will help develop safe and long-term therapies for many brain diseases in human patients.
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412
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New Technologies Provide Quantum Changes in the Scale, Speed, and Success of SELEX Methods and Aptamer Characterization. MOLECULAR THERAPY. NUCLEIC ACIDS 2014; 3:e183. [PMID: 25093707 PMCID: PMC4221594 DOI: 10.1038/mtna.2014.34] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 06/10/2014] [Indexed: 12/24/2022]
Abstract
Single-stranded oligonucleotide aptamers have attracted great attention in the past decade because of their diagnostic and therapeutic potential. These versatile, high affinity and specificity reagents are selected by an iterative in vitro process called SELEX, Systematic Evolution of Ligands by Exponential Enrichment. Numerous SELEX methods have been developed for aptamer selections; some that are simple and straightforward, and some that are specialized and complicated. The method of SELEX is crucial for selection of an aptamer with desired properties; however, success also depends on the starting aptamer library, the target molecule, aptamer enrichment monitoring assays, and finally, the analysis and characterization of selected aptamers. Here, we summarize key recent developments in aptamer selection methods, as well as other aspects of aptamer selection that have significant impact on the outcome. We discuss potential pitfalls and limitations in the selection process with an eye to aid researchers in the choice of a proper SELEX strategy, and we highlight areas where further developments and improvements are desired. We believe carefully designed multiplexed selection methods, when complemented with high-throughput downstream analysis and characterization assays, will yield numerous high-affinity aptamers to protein and small molecule targets, and thereby generate a vast array of reagents for probing basic biological mechanisms and implementing new diagnostic and therapeutic applications in the near future.
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413
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Machado I, Özalp VC, Rezabal E, Schäfer T. DNA aptamers are functional molecular recognition sensors in protic ionic liquids. Chemistry 2014; 20:11820-5. [PMID: 25065686 DOI: 10.1002/chem.201403354] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Indexed: 12/14/2022]
Abstract
The function and structural changes of an AMP molecular aptamer beacon and its molecular recognition capacity for its target, adenosine monophosphate (AMP), was systematically explored in solution with a protic ionic liquid, ethylammonium nitrate (EAN). It could be proven that up to 2 M of EAN in TBS buffer, the AMP molecular aptamer beacon was still capable of recognizing AMP while also maintaining its specificity. The specificity was proven by using the guanosine monophosphate (GMP) as target; GMP is structurally similar to AMP but was not recognized by the aptamer. We also found that in highly concentrated EAN solutions the overall amount of double stranded DNA formed, as well as its respective thermal stability, diminished gradually, but surprisingly the hybridization rate (kh ) of single stranded DNA was significantly accelerated in the presence of EAN. The latter may have important implications in DNA technology for the design of biosensing and DNA-based nanodevices in nonconventional solvents, such as ionic liquids.
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Affiliation(s)
- Isabel Machado
- POLYMAT, University of the Basque Country UPV/EHU, Avda. Tolosa, 72, 20018 - Donostia - San Sebastián (Spain)
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414
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Trevino SG, Levy M. High-throughput bead-based identification of structure-switching aptamer beacons. Chembiochem 2014; 15:1877-81. [PMID: 25056925 PMCID: PMC4161366 DOI: 10.1002/cbic.201402037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Indexed: 12/29/2022]
Abstract
We describe a new platform to identify structure-switching DNA beacon aptamers, which detect small molecules in a specific manner. By clonally amplifying a DNA library designed to fluoresce in response to binding events onto microbeads, aptamer beacons can be selected by stringent fluorescence-assisted sorting. We validated this method by isolating known and novel anti-steroid aptamers from two separate DNA libraries that were structurally enriched with three-way junctions. Importantly, aptamers were retrieved in only a few (three) rounds of selection by this approach and did not require further optimization, significantly streamlining the process of beacon development.
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Affiliation(s)
- Simon G Trevino
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461 (USA)
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415
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416
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Chaput JC. Replicating an expanded genetic alphabet in cells. Chembiochem 2014; 15:1869-71. [PMID: 25044483 DOI: 10.1002/cbic.201402289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Indexed: 12/17/2022]
Abstract
Recent advances in synthetic biology have made it possible to replicate an unnatural base pair in living cells. This study highlights the technologies developed to create a semisynthetic organism with an expanded genetic alphabet and the potential challenges of moving forward.
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Affiliation(s)
- John C Chaput
- Center for Evolutionary Medicine and Bioinformatics, The Biodesign Institute, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-5301 (USA).
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417
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Hollenstein M, Leumann CJ. Synthesis and biochemical characterization of tricyclothymidine triphosphate (tc-TTP). Chembiochem 2014; 15:1901-4. [PMID: 25044722 DOI: 10.1002/cbic.201402116] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Indexed: 01/03/2023]
Abstract
Tricyclo-DNA (tc-DNA) is a conformationally restricted oligonucleotide analogue that exhibits promising properties as a robust antisense agent. Here we report on the synthesis and biochemical characterization of tc-TTP, the triphosphate of a tc-DNA nucleoside containing the base thymine. Tc-TTP turned out to be a substrate for the Vent (exo(-) ) DNA polymerase, a polymerase that allows for multiple incorporations of tc-T nucleotides under primer extension reaction conditions. However, the substrate acceptance is rather low, as also observed for other sugar-modified analogues. Tc-TTP and tc-nucleotide-containing templates do not sustain enzymatic polymerization under physiological conditions; this indicates that tc-DNA-based antisense agents will not enter natural metabolic pathways that lead to long-term toxicity.
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Affiliation(s)
- Marcel Hollenstein
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern (Switzerland).
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418
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Pinheiro VB, Arangundy‐Franklin S, Holliger P. Compartmentalized Self‐Tagging for In Vitro‐Directed Evolution of XNA Polymerases. ACTA ACUST UNITED AC 2014; 57:9.9.1-18. [DOI: 10.1002/0471142700.nc0909s57] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Vitor B. Pinheiro
- Institute of Structural and Molecular Biology, University College, University of London London United Kingdom
- Birkbeck College, University of London London United Kingdom
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419
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Astakhova IK, Wengel J. Scaffolding along nucleic acid duplexes using 2'-amino-locked nucleic acids. Acc Chem Res 2014; 47:1768-77. [PMID: 24749544 DOI: 10.1021/ar500014g] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
CONSPECTUS: Incorporation of chemically modified nucleotide scaffolds into nucleic acids to form assemblies rich in function is an innovative area with great promise for nanotechnology and biomedical and material science applications. The intrinsic biorecognition potential of nucleic acids combined with advanced properties of the locked nucleic acids (LNAs) provide opportunities to develop new nanomaterials and devices like sensors, aptamers, and machines. In this Account, we describe recent research on preparation and investigation of the properties of LNA/DNA hybrids containing functionalized 2'-amino-LNA nucleotides. By application of different chemical reactions, modification of 2'-amino-LNA scaffolds can be efficiently performed in high yields and with various tags, postsynthetically or during the automated oligonucleotide synthesis. The choice of a synthetic method for scaffolding along 2'-amino-LNA mainly depends on the chemical nature of the modification, its price, its availability, and applications of the product. One of the most useful applications of the product LNA/DNA scaffolds containing 2'-amino-LNA is to detect complementary DNA and RNA targets. Examples of these applications include sensing of clinically important single-nucleotide polymorphisms (SNPs) and imaging of nucleic acids in vitro, in cell culture, and in vivo. According to our studies, 2'-amino-LNA scaffolds are efficient within diagnostic probes for DNA and RNA targets and as therapeutics, whereas both 2'-amino- and isomeric 2'-α-l-amino-LNA scaffolds have promising properties for stabilization and detection of DNA nanostructures. Attachment of fluorescent groups to the 2'-amino group results in very high fluorescent quantum yields of the duplexes and remarkable sensitivity of the fluorescence signal to target binding. Notably, fluorescent LNA/DNA probes bind nucleic acid targets with advantages of high affinity and specificity. Thus, molecular motion of nanodevices and programmable self-assembly of chemically modified LNA/DNA nanomaterials can be followed by bright fluorescence signaling from the functionalized LNA units. Another appealing aspect of the amino-LNA scaffolds is specific targeting of nucleic acids and proteins for therapeutic applications. 2'-Amino-LNA/DNA conjugates containing peptide and polyaromatic hydrocarbon (PAH) groups are promising in this context as well as for advanced imaging and diagnostic purposes in vivo. For imaging applications, photostability of fluorescence dyes is of crucial importance. Chemically stable and photostable fluorescent PAH molecules attached to 2'-amino functionality of the 2'-amino-LNA are potent for in vitro and in vivo imaging of DNA and RNA targets. We believe that rational evolution of the biopolymers of Nature may solve the major challenges of the future material science and biomedicine. However, this requires strong scientific progress and efficient interdisciplinary research. Examples of this Account demonstrate that among other synthetic biopolymers, synthetic nucleic acids containing functionalized 2'-amino-LNA scaffolds offer great opportunities for material science, diagnostics, and medicine of the future.
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Affiliation(s)
- I. Kira Astakhova
- Nucleic Acid Center,
Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jesper Wengel
- Nucleic Acid Center,
Department
of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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420
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Abstract
Synthetic biology seeks to probe fundamental aspects of biological form and function by construction (resynthesis) rather than deconstruction (analysis). Here we discuss how such an approach could be applied to assemble synthetic quasibiological systems able to replicate and evolve, illuminating universal properties of life and the search for its origins.
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Affiliation(s)
- James Attwater
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
| | - Philipp Holliger
- Medical Research Council Laboratory of Molecular Biology, Cambridge, UK
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421
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Pinheiro VB, Holliger P. Towards XNA nanotechnology: new materials from synthetic genetic polymers. Trends Biotechnol 2014; 32:321-8. [PMID: 24745974 PMCID: PMC4039137 DOI: 10.1016/j.tibtech.2014.03.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 12/21/2022]
Abstract
Nucleic acids display remarkable properties beyond information storage and propagation. The well-understood base pairing rules have enabled nucleic acids to be assembled into nanostructures of ever increasing complexity. Although nanostructures can be constructed using other building blocks, including peptides and lipids, it is the capacity to evolve that sets nucleic acids apart from all other nanoscale building materials. Nonetheless, the poor chemical and biological stability of DNA and RNA constrain their applications. Recent advances in nucleic acid chemistry and polymerase engineering enable the synthesis, replication, and evolution of a range of synthetic genetic polymers (XNAs) with improved chemical and biological stability. We discuss the impact of this technology on the generation of XNA ligands, enzymes, and nanostructures with tailor-made chemistry.
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Affiliation(s)
- Vitor B Pinheiro
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Philipp Holliger
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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422
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Xu L, Butler KV, Chong J, Wengel J, Kool ET, Wang D. Dissecting the chemical interactions and substrate structural signatures governing RNA polymerase II trigger loop closure by synthetic nucleic acid analogues. Nucleic Acids Res 2014; 42:5863-70. [PMID: 24692664 PMCID: PMC4027217 DOI: 10.1093/nar/gku238] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The trigger loop (TL) of RNA polymerase II (Pol II) is a conserved structural motif that is crucial for Pol II catalytic activity and transcriptional fidelity. The TL remains in an inactive open conformation when the mismatched substrate is bound. In contrast, TL switches from an inactive open state to a closed active state to facilitate nucleotide addition upon the binding of the cognate substrate to the Pol II active site. However, a comprehensive understanding of the specific chemical interactions and substrate structural signatures that are essential to this TL conformational change remains elusive. Here we employed synthetic nucleotide analogues as ‘chemical mutation’ tools coupling with α-amanitin transcription inhibition assay to systematically dissect the key chemical interactions and structural signatures governing the substrate-coupled TL closure in Saccharomyces cerevisiae Pol II. This study reveals novel insights into understanding the molecular basis of TL conformational transition upon substrate binding during Pol II transcription. This synthetic chemical biology approach may be extended to understand the mechanisms of other RNA polymerases as well as other nucleic acid enzymes in future studies.
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Affiliation(s)
- Liang Xu
- Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California, San Diego, La Jolla, CA 92093-0625, USA
| | | | - Jenny Chong
- Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California, San Diego, La Jolla, CA 92093-0625, USA
| | - Jesper Wengel
- Nucleic Acid Center and Biomolecular Nanoscale Engineering Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Eric T Kool
- Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA
| | - Dong Wang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, The University of California, San Diego, La Jolla, CA 92093-0625, USA
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423
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Wu F, Tan C. The engineering of artificial cellular nanosystems using synthetic biology approaches. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2014; 6:369-83. [PMID: 24668724 DOI: 10.1002/wnan.1265] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 02/05/2014] [Accepted: 02/08/2014] [Indexed: 12/26/2022]
Abstract
Artificial cellular systems are minimal systems that mimic certain properties of natural cells, including signaling pathways, membranes, and metabolic pathways. These artificial cells (or protocells) can be constructed following a synthetic biology approach by assembling biomembranes, synthetic gene circuits, and cell-free expression systems. As artificial cells are built from bottom-up using minimal and a defined number of components, they are more amenable to predictive mathematical modeling and engineered controls when compared with natural cells. Indeed, artificial cells have been implemented as drug delivery machineries and in situ protein expression systems. Furthermore, artificial cells have been used as biomimetic systems to unveil new insights into functions of natural cells, which are otherwise difficult to investigate owing to their inherent complexity. It is our vision that the development of artificial cells would bring forth parallel advancements in synthetic biology, cell-free systems, and in vitro systems biology. For further resources related to this article, please visit the WIREs website. Conflict of interests: The authors declare that they have no competing financial interests.
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Affiliation(s)
- Fan Wu
- Department of Biomedical Engineering, University of California Davis, Davis, CA, USA
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424
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Kuwahara M, Obika S. In vitro selection of BNA (LNA) aptamers. ARTIFICIAL DNA, PNA & XNA 2014; 4:39-48. [PMID: 24044051 DOI: 10.4161/adna.25786] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 07/17/2013] [Indexed: 01/03/2023]
Abstract
Recently, we achieved the first in vitro selection of 2'-O,4'-C-methylene bridged/locked nucleic acid (2',4'-BNA/LNA) aptamers. High-affinity thrombin-binding aptamers (TBAs) were obtained from DNA-based libraries containing 2'-O,4'-C-methylene-bridged/linked bicyclic ribonucleotides (B/L nucleotides) in the 5'-primer region, using the method of capillary electrophoresis systematic evolution of ligands by exponential enrichment (CE-SELEX). Furthermore, a similar selection protocol could provide TBAs that contain B/L nucleotides in both primer and random regions. We review technical challenges involved in the generation of various BNA libraries using analogs of B/L nucleoside-5'-triphosphate and polymerase variants and also discuss applications of these libraries to the selection of BNA (LNA) aptamers, as well as future prospects for their therapeutic and diagnostic uses.
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Affiliation(s)
- Masayasu Kuwahara
- Graduate School of Science and Technology; Gunma University; Gunma, Japan
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425
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Hou D, Greenberg MM. DNA interstrand cross-linking upon irradiation of aryl halide C-nucleotides. J Org Chem 2014; 79:1877-84. [PMID: 24559326 DOI: 10.1021/jo4028227] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
γ-Radiolysis kills cells by damaging DNA via radical processes. Many of the radical pathways are O2 dependent, which results in a reduction in the cytotoxicity of ionizing radiation in hypoxic tumor cells. Consequently, there is a need for chemical agents that increase DNA damage by ionizing radiation under O2-deficient conditions. Modified nucleotides that are incorporated in DNA and produce highly reactive σ-radicals are useful as radiosensitizing agents. Aryl halide C-nucleotides (4-6) were incorporated into oligonucleotides by solid-phase synthesis. Duplex DNA containing 4-6 forms interstrand cross-links upon γ-radiolysis under anaerobic conditions or UV irradiation. Deep Vent (exo(-)) DNA polymerase accepted the nucleotide triphosphate of C-nucleotide 6 as a substrate and preferentially incorporated it opposite pyrimidines, but no further extension was detected. Incorporation of 6 in extended products by Deep Vent (exo(-)) during PCR or by Sequenase during copying of single stranded DNA plasmid was undetectable. Aryl halide nucleotide analogues that produce DNA interstrand cross-links under anaerobic conditions upon irradiation are potentially useful as radiosensitizing agents, but further research is needed to identify molecules that are incorporated by DNA polymerases and do not block further polymerization for this approach to be useful in cells.
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Affiliation(s)
- Dianjie Hou
- Department of Chemistry Johns Hopkins University 3400 North Charles Street, Baltimore, Maryland 21218, United States
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426
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De S, Groaz E, Herdewijn P. Tailoring Peptide-Nucleotide Conjugates (PNCs) for Nucleotide Delivery in Bacterial Cells. European J Org Chem 2014. [DOI: 10.1002/ejoc.201301781] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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427
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Bertrand N, Wu J, Xu X, Kamaly N, Farokhzad OC. Cancer nanotechnology: the impact of passive and active targeting in the era of modern cancer biology. Adv Drug Deliv Rev 2014; 66:2-25. [PMID: 24270007 PMCID: PMC4219254 DOI: 10.1016/j.addr.2013.11.009] [Citation(s) in RCA: 1864] [Impact Index Per Article: 186.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/23/2013] [Accepted: 11/13/2013] [Indexed: 12/17/2022]
Abstract
Cancer nanotherapeutics are progressing at a steady rate; research and development in the field has experienced an exponential growth since early 2000's. The path to the commercialization of oncology drugs is long and carries significant risk; however, there is considerable excitement that nanoparticle technologies may contribute to the success of cancer drug development. The pace at which pharmaceutical companies have formed partnerships to use proprietary nanoparticle technologies has considerably accelerated. It is now recognized that by enhancing the efficacy and/or tolerability of new drug candidates, nanotechnology can meaningfully contribute to create differentiated products and improve clinical outcome. This review describes the lessons learned since the commercialization of the first-generation nanomedicines including DOXIL® and Abraxane®. It explores our current understanding of targeted and non-targeted nanoparticles that are under various stages of development, including BIND-014 and MM-398. It highlights the opportunities and challenges faced by nanomedicines in contemporary oncology, where personalized medicine is increasingly the mainstay of cancer therapy. We revisit the fundamental concepts of enhanced permeability and retention effect (EPR) and explore the mechanisms proposed to enhance preferential "retention" in the tumor, whether using active targeting of nanoparticles, binding of drugs to their tumoral targets or the presence of tumor associated macrophages. The overall objective of this review is to enhance our understanding in the design and development of therapeutic nanoparticles for treatment of cancers.
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Affiliation(s)
- Nicolas Bertrand
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jun Wu
- Laboratory of Nanomedicine and Biomaterials, Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, USA
| | - Xiaoyang Xu
- The David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Laboratory of Nanomedicine and Biomaterials, Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, USA
| | - Nazila Kamaly
- Laboratory of Nanomedicine and Biomaterials, Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, USA
| | - Omid C Farokhzad
- Laboratory of Nanomedicine and Biomaterials, Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, USA.
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428
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Direito SOL, Zaura E, Little M, Ehrenfreund P, Röling WFM. Systematic evaluation of bias in microbial community profiles induced by whole genome amplification. Environ Microbiol 2014; 16:643-57. [PMID: 24372985 DOI: 10.1111/1462-2920.12365] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 11/28/2022]
Abstract
Whole genome amplification methods facilitate the detection and characterization of microbial communities in low biomass environments. We examined the extent to which the actual community structure is reliably revealed and factors contributing to bias. One widely used [multiple displacement amplification (MDA)] and one new primer-free method [primase-based whole genome amplification (pWGA)] were compared using a polymerase chain reaction (PCR)-based method as control. Pyrosequencing of an environmental sample and principal component analysis revealed that MDA impacted community profiles more strongly than pWGA and indicated that this related to species GC content, although an influence of DNA integrity could not be excluded. Subsequently, biases by species GC content, DNA integrity and fragment size were separately analysed using defined mixtures of DNA from various species. We found significantly less amplification of species with the highest GC content for MDA-based templates and, to a lesser extent, for pWGA. DNA fragmentation also interfered severely: species with more fragmented DNA were less amplified with MDA and pWGA. pWGA was unable to amplify low molecular weight DNA (< 1.5 kb), whereas MDA was inefficient. We conclude that pWGA is the most promising method for characterization of microbial communities in low-biomass environments and for currently planned astrobiological missions to Mars.
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Affiliation(s)
- Susana O L Direito
- Molecular Cell Physiology, Faculty of Earth and Life Sciences, VU University Amsterdam, Amsterdam, The Netherlands
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429
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Blain JC, Ricardo A, Szostak JW. Synthesis and nonenzymatic template-directed polymerization of 2'-amino-2'-deoxythreose nucleotides. J Am Chem Soc 2014; 136:2033-9. [PMID: 24409991 PMCID: PMC4105081 DOI: 10.1021/ja411950n] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
![]()
Threose nucleic acid (TNA) is a potential
alternative genetic material
that may have played a role in the early evolution of life. We have
developed a novel synthesis of 2′-amino modified TNA nucleosides
(2′-NH2-TNA) based on a cycloaddition reaction between
a glycal and an azodicarboxylate, followed by direct nucleosidation
of the cycloadduct. Using this route, we synthesized the thymine and
guanine 2′-NH2-TNA nucleosides in seven steps with
24% and 12% overall yield, respectively. We then phosphorylated the
guanine nucleoside on the 3′-hydroxyl, activated the phosphate
as the 2-methylimidazolide, and tested the ability of the activated
nucleotide to copy C4 RNA, DNA, and TNA templates by nonenzymatic
primer extension. We measured pseudo-first-order rate constants for
the first nucleotide addition step of 1.5, 0.97, and 0.57 h–1 on RNA, DNA, and TNA templates, respectively, at pH 7.5 and 4 °C
with 150 mM NaCl, 100 mM N-(hydroxylethyl)imidazole
catalyst, and 5 mM activated nucleotide. The activated nucleotide
hydrolyzed with a rate constant of 0.39 h–1, causing
the polymerization reaction to stall before complete template copying
could be achieved. These extension rates are more than 1 order of
magnitude slower than those for amino-sugar ribonucleotides under
the same conditions, and copying of the TNA template, which best represented
a true self-copying reaction, was the slowest of all. The poor kinetics
of 2′-NH2-TNA template copying could give insight
into why TNA was ultimately not used as a genetic material by biological
systems.
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Affiliation(s)
- J Craig Blain
- Howard Hughes Medical Institute and Department of Molecular Biology and Center for Computational and Integrative Biology, Massachusetts General Hospital, 185 Cambridge Street, Boston, Massachusetts 02114, United States
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430
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How Synthetic Biology Will Reconsider Natural Bioluminescence and Its Applications. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2014; 145:3-30. [DOI: 10.1007/978-3-662-43619-6_1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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431
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Zhang C, Wang L, Tu Z, Sun X, He Q, Lei Z, Xu C, Liu Y, Zhang X, Yang J, Liu X, Xu Y. Organophosphorus pesticides detection using broad-specific single-stranded DNA based fluorescence polarization aptamer assay. Biosens Bioelectron 2013; 55:216-9. [PMID: 24384262 DOI: 10.1016/j.bios.2013.12.020] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/13/2013] [Accepted: 12/06/2013] [Indexed: 10/25/2022]
Abstract
An approach is developed to detect the organophosphorus pesticides via competitive binding to a recombinant broad-specificity DNA aptamer with a molecular beacon (MB), the binding of the MB to the aptamer results in the activation of a fluorescent signal, which can be measured for pesticide quantification. Aptamers selected via the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) were structurally modified and truncated to narrow down the binding region of the target, which indicated that loops of the aptamer contributed different functions for different chemical recognition. Thereafter, a variant fused by two different minimum functional structures, was clarified with broad specificity and increased affinity. Further molecular docking and molecular dynamics simulations was conducted to understand the molecular interaction between DNA structure and chemicals. 3D modeling revealed a hot spot area formed by 3 binding sites, forces including hydrogen bonds and van der Waals interactions appear to play a significant role in enabling and stabilizing the binding of chemicals. Finally, an engineered aptamer based approach for the detection of organophosphorus pesticides was successfully applied in a test using a real sample, the limit of quantification (LOQ) for phorate, profenofos, isocarbophos, and omethoate reached 19.2, 13.4, 17.2, and 23.4 nM (0.005 mg L(-1)), respectively.
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Affiliation(s)
- Cunzheng Zhang
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanjing East Road 235, Nanchang 330047, China; Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Li Wang
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Zhui Tu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanjing East Road 235, Nanchang 330047, China
| | - Xing Sun
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Qinghua He
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanjing East Road 235, Nanchang 330047, China
| | - Zhaojing Lei
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Chongxin Xu
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Yuan Liu
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Xiao Zhang
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Jingyi Yang
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China
| | - Xianjin Liu
- Key Laboratory of Control Technology and Standard for Agro-product Safety and Quality, Ministry of Agriculture, Institute of Food Safety, Jiangsu Academy of Agricultural Sciences, Zhongling Street 50, Nanjing 210014, China.
| | - Yang Xu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanjing East Road 235, Nanchang 330047, China.
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432
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The good of two worlds: increasing complexity in cell-free systems. Curr Opin Biotechnol 2013; 24:1037-43. [DOI: 10.1016/j.copbio.2013.03.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Revised: 03/06/2013] [Accepted: 03/09/2013] [Indexed: 11/18/2022]
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433
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Abstract
Diverse engineering strategies have been developed to create enzymes with novel catalytic activities. Among these, computational approaches hold particular promise. Enzymes have been computationally designed to promote several nonbiological reactions, including a Diels-Alder cycloaddition, proton transfer, multistep retroaldol transformations, and metal-dependent hydrolysis of phosphotriesters. Although their efficiencies (kcat/KM = 0.1-100 M(-1) s(-1)) are typically low compared with those of the best natural enzymes (10(6)-10(8) M(-1) s(-1)), these catalysts are excellent starting points for laboratory evolution. This review surveys recent progress in combining computational and evolutionary approaches to enzyme design, together with insights into enzyme function gained from studies of the engineered catalysts.
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Affiliation(s)
- Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zürich, 8093 Zürich, Switzerland.
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434
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Chen T, Romesberg FE. Directed polymerase evolution. FEBS Lett 2013; 588:219-29. [PMID: 24211837 DOI: 10.1016/j.febslet.2013.10.040] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Revised: 10/28/2013] [Accepted: 10/29/2013] [Indexed: 12/23/2022]
Abstract
Polymerases evolved in nature to synthesize DNA and RNA, and they underlie the storage and flow of genetic information in all cells. The availability of these enzymes for use at the bench has driven a revolution in biotechnology and medicinal research; however, polymerases did not evolve to function efficiently under the conditions required for some applications and their high substrate fidelity precludes their use for most applications that involve modified substrates. To circumvent these limitations, researchers have turned to directed evolution to tailor the properties and/or substrate repertoire of polymerases for different applications, and several systems have been developed for this purpose. These systems draw on different methods of creating a pool of randomly mutated polymerases and are differentiated by the process used to isolate the most fit members. A variety of polymerases have been evolved, providing new or improved functionality, as well as interesting new insight into the factors governing activity.
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Affiliation(s)
- Tingjian Chen
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, United States.
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435
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Abstract
RNA molecules are highly modular components that can be used in a variety of contexts for building new metabolic, regulatory and genetic circuits in cells. The majority of synthetic RNA systems to date predominately rely on two-dimensional modularity. However, a better understanding and integration of three-dimensional RNA modularity at structural and functional levels is critical to the development of more complex, functional bio-systems and molecular machines for synthetic biology applications.
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Affiliation(s)
- Wade Grabow
- Department of Chemistry and Biochemistry, Seattle Pacific University3307 Third Avenue West, Seattle, WA 98119USA
| | - Luc Jaeger
- Department of Chemistry and Biochemistry, Bio-Molecular Science and Engineering Program, University of CaliforniaSanta Barbara, CA 93106-9510USA
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436
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Ruiz-Mirazo K, Briones C, de la Escosura A. Prebiotic Systems Chemistry: New Perspectives for the Origins of Life. Chem Rev 2013; 114:285-366. [DOI: 10.1021/cr2004844] [Citation(s) in RCA: 563] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Kepa Ruiz-Mirazo
- Biophysics
Unit (CSIC-UPV/EHU), Leioa, and Department of Logic and Philosophy
of Science, University of the Basque Country, Avenida de Tolosa 70, 20080 Donostia−San Sebastián, Spain
| | - Carlos Briones
- Department
of Molecular Evolution, Centro de Astrobiología (CSIC−INTA, associated to the NASA Astrobiology Institute), Carretera de Ajalvir, Km 4, 28850 Torrejón de Ardoz, Madrid, Spain
| | - Andrés de la Escosura
- Organic
Chemistry Department, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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437
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Shigdar S, Macdonald J, O'Connor M, Wang T, Xiang D, Al.Shamaileh H, Qiao L, Wei M, Zhou SF, Zhu Y, Kong L, Bhattacharya S, Li C, Duan W. Aptamers as theranostic agents: modifications, serum stability and functionalisation. SENSORS 2013; 13:13624-37. [PMID: 24152925 PMCID: PMC3859083 DOI: 10.3390/s131013624] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/24/2013] [Accepted: 09/27/2013] [Indexed: 02/07/2023]
Abstract
Aptamers, and the selection process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) used to generate them, were first described more than twenty years ago. Since then, there have been numerous modifications to the selection procedures. This review discusses the use of modified bases as a means of enhancing serum stability and producing effective therapeutic tools, as well as functionalising these nucleic acids to be used as potential diagnostic agents.
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Affiliation(s)
- Sarah Shigdar
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
- Authors to whom correspondence should be addressed; E-Mails: (S.S.); (W.D.)
| | - Joanna Macdonald
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Michael O'Connor
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Tao Wang
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Dongxi Xiang
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Hadi Al.Shamaileh
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
| | - Liang Qiao
- Storr Liver Unit, at the Westmead Millennium Institute, The University of Sydney at the Westmead Hospital, Westmead NSW 2145, Australia; E-Mail:
| | - Ming Wei
- School of Medical Science and Griffith Health Institute, Griffith University, Gold Coast Campus, Southport 4222, Australia; E-Mail:
| | - Shu-Feng Zhou
- Department of Pharmaceutical Sciences, College of Pharmacy, University of South Florida, Tampa, FL 33612, USA; E-Mail:
| | - Yimin Zhu
- Suzhou Key Laboratory of Nanobiomedicine, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, Jiangsu 215123, China; E-Mail:
| | - Lingxue Kong
- Institute for Frontier Materials, Deakin University, Waurn Ponds, Victoria 3217, Australia; E-Mail:
| | - Santanu Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560 012, India; E-Mail:
| | - ChunGuang Li
- Centre for Complimentary Medicine Research, National Institute of Complementary Medicine, University of Western Sydney, Campbelltown Campus, Penrith, NSW 2751, Australia; E-Mail:
| | - Wei Duan
- School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria 3217, Australia; E-Mails: (J.M.); (M.O.); (T.W.); (D.X.); (H.A.)
- Authors to whom correspondence should be addressed; E-Mails: (S.S.); (W.D.)
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438
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Chiarabelli C, Stano P, Luisi PL. Chemical synthetic biology: a mini-review. Front Microbiol 2013; 4:285. [PMID: 24065964 PMCID: PMC3779815 DOI: 10.3389/fmicb.2013.00285] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 09/04/2013] [Indexed: 01/08/2023] Open
Abstract
Chemical synthetic biology (CSB) is a branch of synthetic biology (SB) oriented toward the synthesis of chemical structures alternative to those present in nature. Whereas SB combines biology and engineering with the aim of synthesizing biological structures or life forms that do not exist in nature – often based on genome manipulation, CSB uses and assembles biological parts, synthetic or not, to create new and alternative structures. A short epistemological note will introduce the theoretical concepts related to these fields, whereas the text will be largely devoted to introduce and comment two main projects of CSB, carried out in our laboratory in the recent years. The “Never Born Biopolymers” project deals with the construction and the screening of RNA and peptide sequences that are not present in nature, whereas the “Minimal Cell” project focuses on the construction of semi-synthetic compartments (usually liposomes) containing the minimal and sufficient number of components to perform the basic function of a biological cell. These two topics are extremely important for both the general understanding of biology in terms of function, organization, and development, and for applied biotechnology.
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439
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Kojima T, Furukawa K, Maruyama H, Inoue N, Tarashima N, Matsuda A, Minakawa N. PCR amplification of 4'-thioDNA using 2'-deoxy-4'-thionucleoside 5'-triphosphates. ACS Synth Biol 2013; 2:529-36. [PMID: 23957635 DOI: 10.1021/sb400074w] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
2'-Deoxy-4'-thioribonucleic acid (4'-thioDNA) having a sulfur atom instead of an oxygen atom in the furanose ring has a nuclease resistance and hybridization ability higher than that of natural DNA. Despite its great potential for various biological applications, a long 4'-thioDNA having all four kinds of 2'-deoxy-4'-thionucleosides has not been reported. In this study, we describe systematic analysis of the incorporation of 2'-deoxy-4'-thionucleoside 5'-triphosphates (dSNTPs) using various DNA polymerases. We found that family B DNA polymerases, which do not have 3'→5' exonuclease activity, could efficiently incorporate dSNTPs via single nucleotide insertion and primer extension. Moreover, 104-mer PCR product was obtained even under the conditions in the presence of all four kinds of dSNTPs when KOD Dash DNA polymerase was used. The resulting PCR product was converted into a natural dsDNA by using PCR with dNTPs, and sequencing of the natural dsDNA revealed that the PCR cycle successfully proceeded without losing the sequence information of the template. To the best of our knowledge, this is the first example of accurate PCR amplification of highly modified DNA in the presence of only unnatural dNTPs.
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Affiliation(s)
- Takamitsu Kojima
- Graduate School of Pharmaceutical
Sciences, The University of Tokushima,
Shomachi 1-78-1, Tokushima 770-8505, Japan
| | - Kazuhiro Furukawa
- Graduate School of Pharmaceutical
Sciences, The University of Tokushima,
Shomachi 1-78-1, Tokushima 770-8505, Japan
| | - Hideto Maruyama
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo
060-0812, Japan
| | - Naonori Inoue
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo
060-0812, Japan
| | - Noriko Tarashima
- Graduate School of Pharmaceutical
Sciences, The University of Tokushima,
Shomachi 1-78-1, Tokushima 770-8505, Japan
| | - Akira Matsuda
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo
060-0812, Japan
| | - Noriaki Minakawa
- Graduate School of Pharmaceutical
Sciences, The University of Tokushima,
Shomachi 1-78-1, Tokushima 770-8505, Japan
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440
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Moors SLC, Herdewijn P, Robben J, Ceulemans A. Cooperative dynamics of a DNA polymerase replicating complex. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:2554-63. [PMID: 24041502 DOI: 10.1016/j.bbapap.2013.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Revised: 08/22/2013] [Accepted: 09/06/2013] [Indexed: 11/15/2022]
Abstract
Engineered DNA polymerases continue to be the workhorses of many applications in biotechnology, medicine and nanotechnology. However, the dynamic interplay between the enzyme and the DNA remains unclear. In this study, we performed an extensive replica exchange with flexible tempering (REFT) molecular dynamics simulation of the ternary replicating complex of the archaeal family B DNA polymerase from the thermophile Thermococcus gorgonarius, right before the chemical step. The convoluted dynamics of the enzyme are reducible to rigid-body motions of six subdomains. Upon binding to the enzyme, the DNA double helix conformation changes from a twisted state to a partially untwisted state. The twisted state displays strong bending motion, whereby the DNA oscillates between a straight and a bent conformation. The dynamics of double-stranded DNA are strongly correlated with rotations of the thumb toward the palm, which suggests an assisting role of the enzyme during DNA translocation. In the complex, the primer-template duplex displays increased preference for the B-DNA conformation at the n-2 and n-3 dinucleotide steps. Interactions at the primer 3' end indicate that Thr541 and Asp540 are the acceptors of the first proton transfer in the chemical step, whereas in the translocation step both residues hold the primer 3' terminus in the vicinity of the priming site, which is crucial for high processivity.
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Affiliation(s)
- Samuel L C Moors
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
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441
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Abstract
Sequence-controlled polymers are macromolecules in which monomer units of different chemical nature are arranged in an ordered fashion. The most prominent examples are biological and have been studied and used primarily by molecular biologists and biochemists. However, recent progress in protein- and DNA-based nanotechnologies has shown the relevance of sequence-controlled polymers to nonbiological applications, including data storage, nanoelectronics, and catalysis. In addition, synthetic polymer chemistry has provided interesting routes for preparing nonnatural sequence-controlled polymers. Although these synthetic macromolecules do not yet compare in functional scope with their natural counterparts, they open up opportunities for controlling the structure, self-assembly, and macroscopic properties of polymer materials.
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Affiliation(s)
- Jean-François Lutz
- Precision Macromolecular Chemistry Group, Institut Charles Sadron, UPR22-CNRS, 23 rue du Loess, Boîte Postale 84047, 67034 Strasbourg Cedex 2, France
| | - Makoto Ouchi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - David R. Liu
- Department of Chemistry and Chemical Biology and the Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Mitsuo Sawamoto
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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442
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Wynne SA, Pinheiro VB, Holliger P, Leslie AGW. Structures of an apo and a binary complex of an evolved archeal B family DNA polymerase capable of synthesising highly cy-dye labelled DNA. PLoS One 2013; 8:e70892. [PMID: 23940661 PMCID: PMC3733885 DOI: 10.1371/journal.pone.0070892] [Citation(s) in RCA: 25] [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: 02/15/2013] [Accepted: 06/24/2013] [Indexed: 11/18/2022] Open
Abstract
Thermophilic DNA polymerases of the polB family are of great importance in biotechnological applications including high-fidelity PCR. Of particular interest is the relative promiscuity of engineered versions of the exo- form of polymerases from the Thermo- and Pyrococcales families towards non-canonical substrates, which enables key advances in Next-generation sequencing. Despite this there is a paucity of structural information to guide further engineering of this group of polymerases. Here we report two structures, of the apo form and of a binary complex of a previously described variant (E10) of Pyrococcus furiosus (Pfu) polymerase with an ability to fully replace dCTP with Cyanine dye-labeled dCTP (Cy3-dCTP or Cy5-dCTP) in PCR and synthesise highly fluorescent “CyDNA” densely decorated with cyanine dye heterocycles. The apo form of Pfu-E10 closely matches reported apo form structures of wild-type Pfu. In contrast, the binary complex (in the replicative state with a duplex DNA oligonucleotide) reveals a closing movement of the thumb domain, increasing the contact surface with the nascent DNA duplex strand. Modelling based on the binary complex suggests how bulky fluorophores may be accommodated during processive synthesis and has aided the identification of residues important for the synthesis of unnatural nucleic acid polymers.
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Affiliation(s)
- Samantha A. Wynne
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Vitor B. Pinheiro
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Philipp Holliger
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Andrew G. W. Leslie
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
- * E-mail:
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443
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Tan C, Saurabh S, Bruchez M, Schwartz R, LeDuc P. Molecular crowding shapes gene expression in synthetic cellular nanosystems. NATURE NANOTECHNOLOGY 2013; 8:602-8. [PMID: 23851358 PMCID: PMC3951305 DOI: 10.1038/nnano.2013.132] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 06/10/2013] [Indexed: 05/16/2023]
Abstract
The integration of synthetic and cell-free biology has made tremendous strides towards creating artificial cellular nanosystems using concepts from solution-based chemistry, where only the concentrations of reacting species modulate gene expression rates. However, it is known that macromolecular crowding, a key feature in natural cells, can dramatically influence biochemical kinetics via volume exclusion effects, which reduce diffusion rates and enhance binding rates of macromolecules. Here, we demonstrate that macromolecular crowding can increase the robustness of gene expression by integrating synthetic cellular components of biological circuits and artificial cellular nanosystems. Furthermore, we reveal how ubiquitous cellular modules, including genetic components, a negative feedback loop and the size of the crowding molecules can fine-tune gene circuit response to molecular crowding. By bridging a key gap between artificial and living cells, our work has implications for efficient and robust control of both synthetic and natural cellular circuits.
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Affiliation(s)
- Cheemeng Tan
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Saumya Saurabh
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Marcel Bruchez
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Russell Schwartz
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Correspondence and requests for materials should be addressed to Philip Leduc & Russell Schwartz. ; . Tel: 412-268-2504. Fax: 412-268-3348
| | - Philip LeDuc
- Lane Center for Computational Biology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Correspondence and requests for materials should be addressed to Philip Leduc & Russell Schwartz. ; . Tel: 412-268-2504. Fax: 412-268-3348
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444
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Laos R, Shaw R, Leal NA, Gaucher E, Benner S. Directed evolution of polymerases to accept nucleotides with nonstandard hydrogen bond patterns. Biochemistry 2013; 52:5288-94. [PMID: 23815560 DOI: 10.1021/bi400558c] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Artificial genetic systems have been developed by synthetic biologists over the past two decades to include additional nucleotides that form additional nucleobase pairs independent of the standard T:A and C:G pairs. Their use in various tools to detect and analyze DNA and RNA requires polymerases that synthesize duplex DNA containing unnatural base pairs. This is especially true for nested polymerase chain reaction (PCR), which has been shown to dramatically lower noise in multiplexed nested PCR if nonstandard nucleotides are used in their external primers. We report here the results of a directed evolution experiment seeking variants of Taq DNA polymerase that can support the nested PCR amplification with external primers containing two particular nonstandard nucleotides, 2-amino-8-(1'-β-d-2'-deoxyribofuranosyl)imidazo[1,2-a]-1,3,5-triazin-4(8H)-one (trivially called P) that pairs with 6-amino-5-nitro-3-(1'-β-d-2'-deoxyribofuranosyl)-2(1H)-pyridone (trivially called Z). Variants emerging from the directed evolution experiments were shown to pause less when challenged in vitro to incorporate dZTP opposite P in a template. Interestingly, several sites involved in the adaptation of Taq polymerases in the laboratory were also found to have displayed "heterotachy" (different rates of change) in their natural history, suggesting that these sites were involved in an adaptive change in natural polymerase evolution. Also remarkably, the polymerases evolved to be less able to incorporate dPTP opposite Z in the template, something that was not selected. In addition to being useful in certain assay architectures, this result underscores the general rule in directed evolution that "you get what you select for".
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Affiliation(s)
- Roberto Laos
- Foundation for Applied Molecular Evolution and The Westheimer Institute of Science and Technology, Gainesville, Florida 32601, United States
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445
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Ibach J, Dietrich L, Koopmans KRM, Nöbel N, Skoupi M, Brakmann S. Identification of a T7 RNA polymerase variant that permits the enzymatic synthesis of fully 2'-O-methyl-modified RNA. J Biotechnol 2013; 167:287-95. [PMID: 23871655 DOI: 10.1016/j.jbiotec.2013.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 07/04/2013] [Accepted: 07/08/2013] [Indexed: 12/11/2022]
Abstract
T7 RNA polymerase is an important biocatalyst that is used in diverse biotechnological applications such as in vitro transcription or protein expression. The enzyme displays high substrate specificity which is payed by significant limitations regarding incorporation of synthetic nucleotide analogs. Of specific interest is enzymatic synthesis of 2'-O-methyl-modified RNA as these nucleic acids exhibit improved biochemical and pharmacokinetic properties that make them attractive for diagnostic and therapeutic purposes. We report here on the development of an activity-based selection/screening approach for assessing polymerase activities in the presence of 2'-O-methyl-modified nucleotides, and on the identification of one variant T7 RNA polymerase which is capable of synthesizing all-2'-O-methyl RNA.
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Affiliation(s)
- Jenny Ibach
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany
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446
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Wright O, Stan GB, Ellis T. Building-in biosafety for synthetic biology. Microbiology (Reading) 2013; 159:1221-1235. [DOI: 10.1099/mic.0.066308-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Oliver Wright
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
| | - Guy-Bart Stan
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
| | - Tom Ellis
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
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447
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Pezo V, Liu FW, Abramov M, Froeyen M, Herdewijn P, Marlière P. Binary Genetic Cassettes for Selecting XNA-Templated DNA Synthesis In Vivo. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201303288] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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448
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Pezo V, Liu FW, Abramov M, Froeyen M, Herdewijn P, Marlière P. Binary genetic cassettes for selecting XNA-templated DNA synthesis in vivo. Angew Chem Int Ed Engl 2013; 52:8139-43. [PMID: 23804524 DOI: 10.1002/anie.201303288] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Indexed: 12/29/2022]
Affiliation(s)
- Valérie Pezo
- ISSB, Génopole, Genavenir6, Equipe Xénome, 5 rue Henri Desbruères, 91030 Evry Cedex, France
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449
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Padirac A, Fujii T, Estévez-Torres A, Rondelez Y. Spatial waves in synthetic biochemical networks. J Am Chem Soc 2013; 135:14586-92. [PMID: 23731347 DOI: 10.1021/ja403584p] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We report the experimental observation of traveling concentration waves and spirals in a chemical reaction network built from the bottom up. The mechanism of the network is an oscillator of the predator-prey type, and this is the first time that predator-prey waves have been observed in the laboratory. The molecular encoding of the nonequilibrium behavior relies on small DNA oligonucleotides that enforce the network connectivity and three purified enzymes that control the reactivity. Wave velocities in the range 80-400 μm min(-1) were measured. A reaction-diffusion model in quantitative agreement with the experiments is proposed. Three fundamental parameters are easy to tune in nucleic acid reaction networks: the topology of the network, the rate constants of the individual reactions, and the diffusion coefficients of the individual species. For this reason, we expect such networks to bring unprecedented opportunities for assaying the principles of spatiotemporal order formation in chemistry.
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Affiliation(s)
- Adrien Padirac
- LIMMS/CNRS-IIS, The University of Tokyo , Komaba 4-6-2, Meguro-ku, Tokyo 153-8505, Japan
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450
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Imaizumi Y, Kasahara Y, Fujita H, Kitadume S, Ozaki H, Endoh T, Kuwahara M, Sugimoto N. Efficacy of base-modification on target binding of small molecule DNA aptamers. J Am Chem Soc 2013; 135:9412-9. [PMID: 23734784 DOI: 10.1021/ja4012222] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Nucleic acid aptamers are receptors of single-stranded oligonucleotides that specifically bind to their targets. Significant interest is currently focused on development of small molecule aptamers owing to their applications in biosensing, diagnostics, and therapeutics involving low molecular weight biomarkers and drugs. Despite great potential for their diverse applications, relatively few aptamers that bind to small molecules have been reported, and methodologies to enhance and broaden their functions by expanding chemical repertories have barely been examined. Here we describe construction of a modified DNA library that includes (E)-5-(2-(N-(2-(N(6)-adeninyl)ethyl))carbamylvinyl)-uracil bases and discovery of high-affinity camptothecin-binding DNA aptamers using a systematic evolution of ligands by the exponential enrichment method. Our results are the first to demonstrate the superior efficacy of base modification on affinity enhancement and the usefulness of unnatural nucleic acid libraries for development of small molecule aptamers.
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Affiliation(s)
- Yuri Imaizumi
- Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
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