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Kong D, Movahedi M, Mahdavi-Amiri Y, Yeung W, Tiburcio T, Chen D, Hili R. Evolutionary Outcomes of Diversely Functionalized Aptamers Isolated from in Vitro Evolution. ACS Synth Biol 2020; 9:43-52. [PMID: 31774997 DOI: 10.1021/acssynbio.9b00222] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Expanding the chemical diversity of aptamers remains an important thrust in the field in order to increase their functional potential. Previously, our group developed LOOPER, which enables the incorporation of up to 16 unique modifications throughout a ssDNA sequence, and applied it to the in vitro evolution of thrombin binders. As LOOPER-derived highly modified nucleic acids polymers are governed by two interrelated evolutionary variables, namely, functional modifications and sequence, the evolution of this polymer contrasts with that of canonical DNA. Herein we provide in-depth analysis of the evolution, including structure-activity relationships, mapping of evolutionary pressures on the library, and analysis of plausible evolutionary pathways that resulted in the first LOOPER-derived aptamer, TBL1. A detailed picture of how TBL1 interacts with thrombin and how it may mimic known peptide binders of thrombin is also proposed. Structural modeling and folding studies afford insights into how the aptamer displays critical modifications and also how modifications enhance the structural stability of the aptamer. A discussion of benefits and potential limitations of LOOPER during in vitro evolution is provided, which will serve to guide future evolutions of this highly modified class of aptamers.
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Affiliation(s)
- Dehui Kong
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Matina Movahedi
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Yasaman Mahdavi-Amiri
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Wayland Yeung
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
| | - Tristan Tiburcio
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Dickson Chen
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
| | - Ryan Hili
- Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, Georgia 30602, United States
- Department of Chemistry, York University, 4700 Keele Street, Toronto, Ontario M3J 1P3, Canada
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52
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Sinha K, Mukhopadhyay CDAS. Quantitative detection of neurotransmitter using aptamer: From diagnosis to therapeutics. J Biosci 2020; 45:44. [PMID: 32098923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Neurotransmitters, the small molecule chemical messenger responsible for nervous system regulation and can control joy, fear, depression, insomnia, craving for carbohydrates, drugs, and alcohols. Variation in neurotransmitter levels is a characteristic manifestation of several neurological diseases. Accurate diagnosis of these diseases caused due to an imbalance in neurotransmitter level followed by impaired transmission of signals between neurons and other body parts remains a great challenge for the clinicians. Recent evidences reveal, artificial single-stranded nucleotides called 'aptamer' are widely used as biosensors, antibody substitutes, diagnostic agents, and for targeted therapy. These aptamers are superior candidate both for early detection and diagnosis of many neurological disorders caused due to suboptimal level of neurotransmitters. Presently, noninvasive neurotransmitter detection by aptamer has been found to be an easy, fast, and cost-effective choice. In addition, increased specificity, stability, affinity, and reproducibility of aptamers, high throughput screening of aptamer-based sensing platforms have been observed. Moreover, clinical applicability of aptamer has also proved to be efficacious, though still at a preliminary stage. Herein, we review salient features of aptamerbased sensing technology used for neurotransmitter detection particularly their chemical modifications, selection, assay development, immobilization, therapeutic efficiency, and stability for early diagnosis of diseases caused due to neurotransmitter imbalance.
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Affiliation(s)
- Koel Sinha
- Centre for Healthcare Science and Technology, Indian Institute of Engineering Science and Technology, Shibpur, Howrah 711 103, India
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53
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Odeh F, Nsairat H, Alshaer W, Ismail MA, Esawi E, Qaqish B, Bawab AA, Ismail SI. Aptamers Chemistry: Chemical Modifications and Conjugation Strategies. Molecules 2019; 25:E3. [PMID: 31861277 PMCID: PMC6982925 DOI: 10.3390/molecules25010003] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/14/2019] [Accepted: 12/17/2019] [Indexed: 12/21/2022] Open
Abstract
Soon after they were first described in 1990, aptamers were largely recognized as a new class of biological ligands that can rival antibodies in various analytical, diagnostic, and therapeutic applications. Aptamers are short single-stranded RNA or DNA oligonucleotides capable of folding into complex 3D structures, enabling them to bind to a large variety of targets ranging from small ions to an entire organism. Their high binding specificity and affinity make them comparable to antibodies, but they are superior regarding a longer shelf life, simple production and chemical modification, in addition to low toxicity and immunogenicity. In the past three decades, aptamers have been used in a plethora of therapeutics and drug delivery systems that involve innovative delivery mechanisms and carrying various types of drug cargos. However, the successful translation of aptamer research from bench to bedside has been challenged by several limitations that slow down the realization of promising aptamer applications as therapeutics at the clinical level. The main limitations include the susceptibility to degradation by nucleases, fast renal clearance, low thermal stability, and the limited functional group diversity. The solution to overcome such limitations lies in the chemistry of aptamers. The current review will focus on the recent arts of aptamer chemistry that have been evolved to refine the pharmacological properties of aptamers. Moreover, this review will analyze the advantages and disadvantages of such chemical modifications and how they impact the pharmacological properties of aptamers. Finally, this review will summarize the conjugation strategies of aptamers to nanocarriers for developing targeted drug delivery systems.
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Affiliation(s)
- Fadwa Odeh
- Faculty of Science, The University of Jordan, Amman 11942, Jordan; (F.O.); (H.N.); (A.A.B.)
- Hamdi Mango Center for Scientific Research, The University of Jordan, Amman 11942, Jordan
| | - Hamdi Nsairat
- Faculty of Science, The University of Jordan, Amman 11942, Jordan; (F.O.); (H.N.); (A.A.B.)
| | - Walhan Alshaer
- Cell Therapy Center, The University of Jordan, Amman 11942, Jordan
| | - Mohammad A. Ismail
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
| | - Ezaldeen Esawi
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
| | - Baraa Qaqish
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
| | - Abeer Al Bawab
- Faculty of Science, The University of Jordan, Amman 11942, Jordan; (F.O.); (H.N.); (A.A.B.)
- Hamdi Mango Center for Scientific Research, The University of Jordan, Amman 11942, Jordan
| | - Said I. Ismail
- Faculty of Medicine, The University of Jordan, Amman 11942, Jordan; (M.A.I.); (E.E.); (B.Q.); (S.I.I.)
- Qatar Genome Project, Qatar Foundation, Doha 5825, Qatar
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Tan Y, Li Y, Tang F. Nucleic Acid Aptamer: A Novel Potential Diagnostic and Therapeutic Tool for Leukemia. Onco Targets Ther 2019; 12:10597-10613. [PMID: 31824168 PMCID: PMC6900352 DOI: 10.2147/ott.s223946] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 10/14/2019] [Indexed: 12/23/2022] Open
Abstract
Leukemia immunotherapy has been dominant via using synthetic antibodies to target cluster of differentiation (CD) molecules, nevertheless inevitable cytotoxicity and immunogenicity would limit its development. Recently, increasing reports have focused on nucleic acid aptamers, a class of high-affinity nucleic acid ligands. Aptamers purportedly serve as “chemical antibodies”, have negligible cytotoxicity and low immunogenicity, and would be widely applied for the therapy and diagnosis of various diseases, especially leukemia. In the preclinical applications, nucleic acid aptamers have displayed the augmented specificity and selectivity via recognizing targets on leukemia cells based on unique three-dimensional conformations. As small molecules with nucleic acid characteristics, aptamers need to be chemically modified to resist nuclease degradation, renal clearance and improve binding affinities. Moreover, aptamers can be linked with neoteric detection techniques to enhance sensitivity and selectivity of diagnosis and therapy. In this review, we summarized aptamers’ preparation, chemical modification and conjugation, and discussed the application of aptamers in diagnosis and treatment of leukemia through highly specifically recognizing target molecules. Significantly, the application prospect of aptamers in fusion genes would be introduced.
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Affiliation(s)
- Yuan Tan
- Department of Clinical Laboratory, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, People's Republic of China
| | - Yuejin Li
- Department of Clinical Laboratory, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, People's Republic of China
| | - Faqing Tang
- Department of Clinical Laboratory, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha 410013, People's Republic of China
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Zhao L, Qi X, Yan X, Huang Y, Liang X, Zhang L, Wang S, Tan W. Engineering Aptamer with Enhanced Affinity by Triple Helix-Based Terminal Fixation. J Am Chem Soc 2019; 141:17493-17497. [DOI: 10.1021/jacs.9b09292] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Lianhui Zhao
- College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266003, China
| | - Xiaoyan Qi
- College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266003, China
| | - Xiaochen Yan
- College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266003, China
| | - Yunfei Huang
- College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266003, China
| | - Xingguo Liang
- College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266003, China
| | - Liqin Zhang
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/BioSensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
- Inspiratio Biosciences, Inc., Fremont, California 94538, United States
- Department of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611, United States
| | - Sai Wang
- College of Food Science and Engineering, Ocean University of China, Qingdao, Shandong 266003, China
| | - Weihong Tan
- Molecular Science and Biomedicine Laboratory (MBL), State Key Laboratory of Chemo/BioSensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Biology, and Aptamer Engineering Center of Hunan Province, Hunan University, Changsha, Hunan 410082, China
- Institute of Molecular Medicine (IMM), Renji Hospital, Shanghai Jiao Tong University School of Medicine, and College of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Department of Chemistry and Department of Physiology and Functional Genomics, Center for Research at the Bio/Nano Interface, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida, Gainesville, Florida 32611, United States
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56
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Wang C, Sun Y, Zhao Q. A sensitive thrombin-linked sandwich immunoassay for protein targets using high affinity phosphorodithioate modified aptamer for thrombin labeling. Talanta 2019; 207:120280. [PMID: 31594565 DOI: 10.1016/j.talanta.2019.120280] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 08/14/2019] [Accepted: 08/17/2019] [Indexed: 02/07/2023]
Abstract
Thrombin and its aptamers have been well studied and widely used as models in aptamer based assays and sensors. Here we reported a thrombin-linked sandwich immunoassay for proteins to demonstrate new applications of thrombin and the aptamers, converting protein detection to analysis of thrombin label. In this assay, target protein was sandwiched by the capture antibody on a microplate and the biotinylated detection antibody. Thrombin bound to one biotinylated aptamer, and then the thrombin-labeled aptamer was attached on the sandwich complex through streptavidin-biotin interaction by using streptavidin as a linker. Thrombin catalyzed cleavage of fluorogenic peptide substrates, generating fluorescence signals for target detection. Among a few different anti-thrombin aptamers, the use of one nuclease resistant RNA aptamer having phosphorodithioate (PS2) modification on a specific backbone position enabled higher assay sensitivity due to its much higher affinity. This thrombin-linked sandwich immunoassay allowed detection of prostate-specific antigen (PSA) at 2 pM, an important protein related cancer disease, with high sensitivity and specificity. The strategy was general, and also enabled sensitive detection of botulinum neurotoxin type A (BoNTA) light chain, one toxin protein causing risk to human health. This assay combines advantages of antibody recognition, aptamer affinity labeling, high affinity of aptamers, and enzyme activity of thrombin. Labeling thrombin on the immunosandwich complex through simple affinity binding overcomes limitations of covalent conjugating enzyme on antibody in conventional immunoassay. This assay is promising in applications for protein detection.
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Affiliation(s)
- Chao Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yang Sun
- The People's Hospital of Peking University, Beijing, 100044, China
| | - Qiang Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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57
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A review on native and denaturing purification methods for non-coding RNA (ncRNA). J Chromatogr B Analyt Technol Biomed Life Sci 2019; 1120:71-79. [PMID: 31071581 DOI: 10.1016/j.jchromb.2019.04.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/20/2019] [Accepted: 04/15/2019] [Indexed: 12/20/2022]
Abstract
Recently, non-coding RNA (ncRNA) became the centerpiece of human genome research. Modern ncRNA-based research has revolutionized disease diagnosis and therapeutics. However, decoding structural/functional information of ncRNA requires large amount of pure RNA, and hence effective RNA preparation and purification protocols. This review focuses on purification schemes of synthetic oligonucleotides, particularly liquid chromatographic (LC) techniques as improved alternatives to urea-polyacrylamide gel electrophoresis (urea-PAGE) purification. Moreover, the review summarizes the shortcomings of urea-PAGE purification method and details the chromatographic purification such as affinity, ion-exchange (IE) or size-exclusion (SE) chromatography. Specifically, we discuss denaturing and native RNA purification schemes with newest developments. In short, the review evaluates nucleic acid purification schemes required for various structural analyses.
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58
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Zavyalova E, Kopylov A. Energy Transfer as A Driving Force in Nucleic Acid⁻Protein Interactions. Molecules 2019; 24:molecules24071443. [PMID: 30979095 PMCID: PMC6480146 DOI: 10.3390/molecules24071443] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 12/19/2022] Open
Abstract
Many nucleic acid–protein structures have been resolved, though quantitative structure-activity relationship remains unclear in many cases. Thrombin complexes with G-quadruplex aptamers are striking examples of a lack of any correlation between affinity, interface organization, and other common parameters. Here, we tested the hypothesis that affinity of the aptamer–protein complex is determined with the capacity of the interface to dissipate energy of binding. Description and detailed analysis of 63 nucleic acid–protein structures discriminated peculiarities of high-affinity nucleic acid–protein complexes. The size of the amino acid sidechain in the interface was demonstrated to be the most significant parameter that correlates with affinity of aptamers. This observation could be explained in terms of need of efficient energy transfer from interacting residues. Application of energy dissipation theory provided an illustrative tool for estimation of efficiency of aptamer–protein complexes. These results are of great importance for a design of efficient aptamers.
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Affiliation(s)
| | - Alexey Kopylov
- Chemistry Department, Lomonosov Moscow State University, 119991 Moscow, Russia.
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59
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DNA aptamers for the recognition of HMGB1 from Plasmodium falciparum. PLoS One 2019; 14:e0211756. [PMID: 30964875 PMCID: PMC6456224 DOI: 10.1371/journal.pone.0211756] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/24/2019] [Indexed: 12/21/2022] Open
Abstract
Rapid Diagnostic Tests (RDTs) for malaria are restricted to a few biomarkers and antibody-mediated detection. However, the expression of commonly used biomarkers varies geographically and the sensibility of immunodetection can be affected by batch-to-batch differences or limited thermal stability. In this study we aimed to overcome these limitations by identifying a potential biomarker and by developing molecular sensors based on aptamer technology. Using gene expression databases, ribosome profiling analysis, and structural modeling, we find that the High Mobility Group Box 1 protein (HMGB1) of Plasmodium falciparum is highly expressed, structurally stable, and present along all blood-stages of P. falciparum infection. To develop biosensors, we used in vitro evolution techniques to produce DNA aptamers for the recombinantly expressed HMG-box, the conserved domain of HMGB1. An evolutionary approach for evaluating the dynamics of aptamer populations suggested three predominant aptamer motifs. Representatives of the aptamer families were tested for binding parameters to the HMG-box domain using microscale thermophoresis and rapid kinetics. Dissociation constants of the aptamers varied over two orders of magnitude between nano- and micromolar ranges while the aptamer-HMG-box interaction occurred in a few seconds. The specificity of aptamer binding to the HMG-box of P. falciparum compared to its human homolog depended on pH conditions. Altogether, our study proposes HMGB1 as a candidate biomarker and a set of sensing aptamers that can be further developed into rapid diagnostic tests for P. falciparum detection.
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60
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Flamme M, McKenzie LK, Sarac I, Hollenstein M. Chemical methods for the modification of RNA. Methods 2019; 161:64-82. [PMID: 30905751 DOI: 10.1016/j.ymeth.2019.03.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 02/06/2023] Open
Abstract
RNA is often considered as being the vector for the transmission of genetic information from DNA to the protein synthesis machinery. However, besides translation RNA participates in a broad variety of fundamental biological roles such as gene expression and regulation, protein synthesis, and even catalysis of chemical reactions. This variety of function combined with intricate three-dimensional structures and the discovery of over 100 chemical modifications in natural RNAs require chemical methods for the modification of RNAs in order to investigate their mechanism, location, and exact biological roles. In addition, numerous RNA-based tools such as ribozymes, aptamers, or therapeutic oligonucleotides require the presence of additional chemical functionalities to strengthen the nucleosidic backbone against degradation or enhance the desired catalytic or binding properties. Herein, the two main methods for the chemical modification of RNA are presented: solid-phase synthesis using phosphoramidite precursors and the enzymatic polymerization of nucleoside triphosphates. The different synthetic and biochemical steps required for each method are carefully described and recent examples of practical applications based on these two methods are discussed.
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Affiliation(s)
- Marie Flamme
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France; Sorbonne Université, Collège doctoral, F-75005 Paris, France
| | - Luke K McKenzie
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Ivo Sarac
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
| | - Marcel Hollenstein
- Institut Pasteur, Department of Structural Biology and Chemistry, Laboratory for Bioorganic Chemistry of Nucleic Acids, CNRS UMR3523, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France.
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61
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Egli M, Lybrand TP. Enhanced Dispersion and Polarization Interactions Achieved through Dithiophosphate Group Incorporation Yield a Dramatic Binding Affinity Increase for an RNA Aptamer-Thrombin Complex. J Am Chem Soc 2019; 141:4445-4452. [PMID: 30794399 DOI: 10.1021/jacs.9b00104] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Regiospecific replacement of a single phosphate (PO2) by a dithiophosphate (PS2) group in an RNA can dramatically increase its binding affinity for a target protein. Thus, complexes between antithrombin and anti-VEGF RNA aptamers with single dithiophosphate moieties and thrombin and VEGF, respectively, display equilibrium dissociation constants KD of ca. 1 pM, 1000-fold tighter than the native RNA complexes (ca. 1 nM). Inspection of crystal structures of the native and PS2-RNA aptamer:thrombin complexes reveals an RNA-induced fit in the latter. This leads to a close approach between PS2 and the phenyl ring edge of Phe-232 that is surrounded by pairs of lysines and arginines. To better understand the origins of the tighter binding and individual contributions to the interaction energy, we carried out QM calculations with phosphate- and dithiophosphate-benzene and dimethyl phosphate- and dimethyl dithiophosphate-benzene model systems. These calculations demonstrate that the dithiophosphate-benzene interaction is much stronger than the corresponding interaction with phosphate. QM/MM calculations with the full complexes confirmed this finding and support the hypothesis that the electric field generated by basic residues surrounding Phe-232 is key to the polarization of the PS2 moiety. Thus, disparate polarization and dispersion energies between the PO2 and PS2 complexes contribute critically to the difference in binding affinity. By comparison, easier desolvation of the dithiophosphate group compared to phosphate does not contribute decisively to the observed difference in binding affinity. Favorable polarization and dispersion energies may be a general feature of the dramatic affinity gains seen for complexes between RNAs carrying dithiophosphate groups and their binding proteins.
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62
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Seo M, Lei L, Egli M. Label-Free Electrophoretic Mobility Shift Assay (EMSA) for Measuring Dissociation Constants of Protein-RNA Complexes. CURRENT PROTOCOLS IN NUCLEIC ACID CHEMISTRY 2019; 76:e70. [PMID: 30461222 PMCID: PMC6391183 DOI: 10.1002/cpnc.70] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The electrophoretic mobility shift assay (EMSA) is a well-established method to detect formation of complexes between proteins and nucleic acids and to determine, among other parameters, equilibrium constants for the interaction. Mixtures of protein and nucleic acid solutions of various ratios are analyzed via polyacrylamide gel electrophoresis (PAGE) under native conditions. In general, protein-nucleic acid complexes will migrate more slowly than the free nucleic acid. From the distributions of the nucleic acid components in the observed bands in individual gel lanes, quantitative parameters such as the dissociation constant (Kd ) of the interaction can be measured. This article describes a simple and rapid EMSA that relies either on precast commercial or handcast polyacrylamide gels and uses unlabeled protein and nucleic acid. Nucleic acids are instead detected with SYBR Gold stain and band intensities established with a standard gel imaging system. We used this protocol specifically to determine Kd values for complexes between the PAZ domain of Argonaute 2 (Ago2) enzyme and native and chemically modified RNA oligonucleotides. EMSA-based equilibrium constants are compared to those determined with isothermal titration calorimetry (ITC). Advantages and limitations of this simple EMSA are discussed by comparing it to other techniques used for determination of equilibrium constants of protein-RNA interactions, and a troubleshooting guide is provided. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Minguk Seo
- Department of Biochemistry, School of Medicine, Vanderbilt University,
Nashville TN 37232
| | - Li Lei
- Department of Biochemistry, School of Medicine, Vanderbilt University,
Nashville TN 37232
| | - Martin Egli
- Department of Biochemistry, School of Medicine, Vanderbilt University,
Nashville TN 37232
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63
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Putative Mechanisms Underlying High Inhibitory Activities of Bimodular DNA Aptamers to Thrombin. Biomolecules 2019; 9:biom9020041. [PMID: 30682825 PMCID: PMC6406280 DOI: 10.3390/biom9020041] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 01/10/2023] Open
Abstract
Nucleic acid aptamers are prospective molecular recognizing elements. Similar to antibodies, aptamers are capable of providing specific recognition due to their spatial structure. However, the apparent simplicity of oligonucleotide folding is often elusive, as there is a balance between several conformations and, in some cases, oligomeric structures. This research is focused on establishing a thermodynamic background and the conformational heterogeneity of aptamers taking a series of thrombin DNA aptamers having G-quadruplex and duplex modules as an example. A series of aptamers with similar modular structures was characterized with spectroscopic and chromatographic techniques, providing examples of the conformational homogeneity of aptamers with high inhibitory activity, as well as a mixture of monomeric and oligomeric species for aptamers with low inhibitory activity. Thermodynamic parameters for aptamer unfolding were calculated, and their correlation with aptamer functional activity was found. Detailed analysis of thrombin complexes with G-quadruplex aptamers bound to exosite I revealed the similarity of the interfaces of aptamers with drastically different affinities to thrombin. It could be suggested that there are some events during complex formation that have a larger impact on the affinity than the states of initial and final macromolecules. Possible mechanisms of the complex formation and a role of the duplex module in the association process are discussed.
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64
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Blanco C, Janzen E, Pressman A, Saha R, Chen IA. Molecular Fitness Landscapes from High-Coverage Sequence Profiling. Annu Rev Biophys 2019; 48:1-18. [PMID: 30601678 DOI: 10.1146/annurev-biophys-052118-115333] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The function of fitness (or molecular activity) in the space of all possible sequences is known as the fitness landscape. Evolution is a random walk on the fitness landscape, with a bias toward climbing hills. Mapping the topography of real fitness landscapes is fundamental to understanding evolution, but previous efforts were hampered by the difficulty of obtaining large, quantitative data sets. The accessibility of high-throughput sequencing (HTS) has transformed this study, enabling large-scale enumeration of fitness for many mutants and even complete sequence spaces in some cases. We review the progress of high-throughput studies in mapping molecular fitness landscapes, both in vitro and in vivo, as well as opportunities for future research. Such studies are rapidly growing in number. HTS is expected to have a profound effect on the understanding of real molecular fitness landscapes.
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Affiliation(s)
- Celia Blanco
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , ,
| | - Evan Janzen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , , .,Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
| | - Abe Pressman
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , , .,Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
| | - Ranajay Saha
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA; , , , ,
| | - Irene A Chen
- Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
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65
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Antipova OM, Zavyalova EG, Golovin AV, Pavlova GV, Kopylov AM, Reshetnikov RV. Advances in the Application of Modified Nucleotides in SELEX Technology. BIOCHEMISTRY (MOSCOW) 2018; 83:1161-1172. [PMID: 30472954 DOI: 10.1134/s0006297918100024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Aptamers are widely used as molecular recognition elements for detecting and blocking functional biological molecules. Since the common "alphabet" of DNA and RNA consists of only four letters, the chemical diversity of aptamers is less than the diversity of protein recognition elements built of 20 amino acids. Chemical modification of nucleotides enlarges the potential of DNA/RNA aptamers. This review describes the latest achievements in a variety of approaches to aptamers selection with an extended genetic alphabet.
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Affiliation(s)
- O M Antipova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia. .,Apto-Pharm Ltd., Moscow, 115564, Russia
| | - E G Zavyalova
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Apto-Pharm Ltd., Moscow, 115564, Russia
| | - A V Golovin
- Apto-Pharm Ltd., Moscow, 115564, Russia.,Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119234, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991, Russia
| | - G V Pavlova
- Apto-Pharm Ltd., Moscow, 115564, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991, Russia.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.,Burdenko National Scientific and Practical Center for Neurosurgery, Ministry of Healthcare of the Russian Federation, Moscow, 125047, Russia
| | - A M Kopylov
- Lomonosov Moscow State University, Faculty of Chemistry, Moscow, 119991, Russia.,Apto-Pharm Ltd., Moscow, 115564, Russia
| | - R V Reshetnikov
- Apto-Pharm Ltd., Moscow, 115564, Russia.,Lomonosov Moscow State University, Faculty of Bioengineering and Bioinformatics, Moscow, 119234, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, 119991, Russia.,Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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66
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Clinical aspects of radiolabeled aptamers in diagnostic nuclear medicine: A new class of targeted radiopharmaceuticals. Bioorg Med Chem 2018; 27:2282-2291. [PMID: 30502114 DOI: 10.1016/j.bmc.2018.11.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/16/2018] [Accepted: 11/21/2018] [Indexed: 12/31/2022]
Abstract
Targeted radiopharmaceuticals offer the possibility of improved imaging with reduced side effects. Up to now, a variety of biological receptors such as aptamers have been successfully radiolabeled and applied to diagnostic imaging of cancers. The concept of using radio-labeled aptamers for binding to their targets has stimulated an immense body of research in diagnostic nuclear medicine. These biological recognition elements are single-stranded oligonucleotides that interact with their target molecules with high affinity and specificity in unique three-dimensional structures. Because of their high affinity and specificity, the receptor-binding aptamers labeled with gamma emitters such as 99mTc, 64Cu, 111In, 18F and 67Ga can facilitate the visualization of receptor-expressing tissues noninvasively. Compared to the antibody-based radiopharmaceuticals, the radiolabeled aptamers provide a number of advantages for clinical diagnostics including high stability, low cost, and ease of production and modification, low immunogenicity and, especially, superior tissue penetration because of their smaller size. In this review, we present recent progresses and challenges in aptamer-based diagnostic radiopharmaceuticals and highlight some representative applications of aptamers in nuclear medicine.
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Yu F, Zhao Q, Zhang D, Yuan Z, Wang H. Affinity Interactions by Capillary Electrophoresis: Binding, Separation, and Detection. Anal Chem 2018; 91:372-387. [PMID: 30392351 DOI: 10.1021/acs.analchem.8b04741] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Fangzhi Yu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing , 100085 , China.,University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Qiang Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing , 100085 , China.,University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Dapeng Zhang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing , 100085 , China
| | - Zheng Yuan
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing , 100085 , China.,University of Chinese Academy of Sciences , Beijing , 100049 , China
| | - Hailin Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology , Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences , Beijing , 100085 , China.,University of Chinese Academy of Sciences , Beijing , 100049 , China
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Bayat P, Nosrati R, Alibolandi M, Rafatpanah H, Abnous K, Khedri M, Ramezani M. SELEX methods on the road to protein targeting with nucleic acid aptamers. Biochimie 2018; 154:132-155. [PMID: 30193856 DOI: 10.1016/j.biochi.2018.09.001] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 09/02/2018] [Indexed: 12/14/2022]
Abstract
Systematic evolution of ligand by exponential enrichment (SELEX) is an efficient method used to isolate high-affinity single stranded oligonucleotides from a large random sequence pool. These SELEX-derived oligonucleotides named aptamer, can be selected against a broad spectrum of target molecules including proteins, cells, microorganisms and chemical compounds. Like antibodies, aptamers have a great potential in interacting with and binding to their targets through structural recognition and are therefore called "chemical antibodies". However, aptamers offer advantages over antibodies including smaller size, better tissue penetration, higher thermal stability, lower immunogenicity, easier production, lower cost of synthesis and facilitated conjugation or modification with different functional moieties. Thus, aptamers represent an attractive substitution for protein antibodies in the fields of biomarker discovery, diagnosis, imaging and targeted therapy. Enormous interest in aptamer technology triggered the development of SELEX that has underwent numerous modifications since its introduction in 1990. This review will discuss the recent advances in SELEX methods and their advantages and limitations. Aptamer applications are also briefly outlined in this review.
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Affiliation(s)
- Payam Bayat
- Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Rahim Nosrati
- Cellular and Molecular Research Center, Faculty of Medicine, Guilan University of Medical Sciences, Rasht, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mona Alibolandi
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Houshang Rafatpanah
- Inflammation and Inflammatory Diseases Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Khalil Abnous
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mostafa Khedri
- Department of Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Ramezani
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
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Röthlisberger P, Hollenstein M. Aptamer chemistry. Adv Drug Deliv Rev 2018; 134:3-21. [PMID: 29626546 DOI: 10.1016/j.addr.2018.04.007] [Citation(s) in RCA: 218] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Accepted: 04/03/2018] [Indexed: 12/12/2022]
Abstract
Aptamers are single-stranded DNA or RNA molecules capable of tightly binding to specific targets. These functional nucleic acids are obtained by an in vitro Darwinian evolution method coined SELEX (Systematic Evolution of Ligands by EXponential enrichment). Compared to their proteinaceous counterparts, aptamers offer a number of advantages including a low immunogenicity, a relative ease of large-scale synthesis at affordable costs with little or no batch-to-batch variation, physical stability, and facile chemical modification. These alluring properties have propelled aptamers into the forefront of numerous practical applications such as the development of therapeutic and diagnostic agents as well as the construction of biosensing platforms. However, commercial success of aptamers still proceeds at a weak pace. The main factors responsible for this delay are the susceptibility of aptamers to degradation by nucleases, their rapid renal filtration, suboptimal thermal stability, and the lack of functional group diversity. Here, we describe the different chemical methods available to mitigate these shortcomings. Particularly, we describe the chemical post-SELEX processing of aptamers to include functional groups as well as the inclusion of modified nucleoside triphosphates into the SELEX protocol. These methods will be illustrated with successful examples of chemically modified aptamers used as drug delivery systems, in therapeutic applications, and as biosensing devices.
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Kaur H, Bruno JG, Kumar A, Sharma TK. Aptamers in the Therapeutics and Diagnostics Pipelines. Theranostics 2018; 8:4016-4032. [PMID: 30128033 PMCID: PMC6096388 DOI: 10.7150/thno.25958] [Citation(s) in RCA: 225] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/16/2018] [Indexed: 12/17/2022] Open
Abstract
Aptamers are short single-stranded DNA or RNA oligonucleotides that can selectively bind to small molecular ligands or protein targets with high affinity and specificity, by acquiring unique three-dimensional structures. Aptamers have the advantage of being highly specific, relatively small in size, non-immunogenic and can be easily stabilized by chemical modifications, thus allowing expansion of their diagnostic and therapeutic potential. Since the invention of aptamers in the early 1990s, great efforts have been made to make them clinically relevant for diseases like macular degeneration, cancer, thrombosis and inflammatory diseases. Furthermore, owing to the aforementioned advantages and unique adaptability of aptamers to point-of-care platforms, aptamer technology has created a stable niche in the field of in vitro diagnostics by enhancing the speed and accuracy of diagnoses. The aim of this review is to give an overview on aptamers, highlight the inherent therapeutic and diagnostic opportunities and challenges associated with them and present various aptamers that have reached therapeutic clinical trials, diagnostic markets or that have immediate translational potential for therapeutics and diagnostics applications.
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Affiliation(s)
| | - John G. Bruno
- Operational Technologies Corporation, 4100 NW Loop 410, Suite 100, San Antonio, Texas 78229, USA
| | - Amit Kumar
- Discipline of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore, 453552, India
| | - Tarun Kumar Sharma
- Center for Biodesign and Diagnostics, Translational Health Science and Technology Institute (THSTI), Faridabad-121001, Haryana, India
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71
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Dolot R, Lam CH, Sierant M, Zhao Q, Liu FW, Nawrot B, Egli M, Yang X. Crystal structures of thrombin in complex with chemically modified thrombin DNA aptamers reveal the origins of enhanced affinity. Nucleic Acids Res 2018; 46:4819-4830. [PMID: 29684204 PMCID: PMC5961234 DOI: 10.1093/nar/gky268] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/26/2018] [Accepted: 04/15/2018] [Indexed: 01/11/2023] Open
Abstract
Thrombin-binding aptamer (TBA) is a DNA 15-mer of sequence 5'-GGT TGG TGT GGT TGG-3' that folds into a G-quadruplex structure linked by two T-T loops located on one side and a T-G-T loop on the other. These loops are critical for post-SELEX modification to improve TBA target affinity. With this goal in mind we synthesized a T analog, 5-(indolyl-3-acetyl-3-amino-1-propenyl)-2'-deoxyuridine (W) to substitute one T or a pair of Ts. Subsequently, the affinity for each analog was determined by biolayer interferometry. An aptamer with W at position 4 exhibited about 3-fold increased binding affinity, and replacing both T4 and T12 with W afforded an almost 10-fold enhancement compared to native TBA. To better understand the role of the substituent's aromatic moiety, an aptamer with 5-(methyl-3-acetyl-3-amino-1-propenyl)-2'-deoxyuridine (K; W without the indole moiety) in place of T4 was also synthesized. This K4 aptamer was found to improve affinity 7-fold relative to native TBA. Crystal structures of aptamers with T4 replaced by either W or K bound to thrombin provide insight into the origins of the increased affinities. Our work demonstrates that facile chemical modification of a simple DNA aptamer can be used to significantly improve its binding affinity for a well-established pharmacological target protein.
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Affiliation(s)
- Rafal Dolot
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90–363 Lodz, Sienkiewicza 112, Poland
| | - Curtis H Lam
- AM Biotechnologies, LLC, 12521 Gulf Freeway, Houston, TX 77034, USA
| | - Malgorzata Sierant
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90–363 Lodz, Sienkiewicza 112, Poland
| | - Qiang Zhao
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Feng-Wu Liu
- School of Pharmaceutical Sciences, Zhengzhou University, Science Avenue 100, Zhengzhou 450001, Henan, China
| | - Barbara Nawrot
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90–363 Lodz, Sienkiewicza 112, Poland
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA
| | - Xianbin Yang
- AM Biotechnologies, LLC, 12521 Gulf Freeway, Houston, TX 77034, USA
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72
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Kalra P, Dhiman A, Cho WC, Bruno JG, Sharma TK. Simple Methods and Rational Design for Enhancing Aptamer Sensitivity and Specificity. Front Mol Biosci 2018; 5:41. [PMID: 29868605 PMCID: PMC5966647 DOI: 10.3389/fmolb.2018.00041] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/13/2018] [Indexed: 12/27/2022] Open
Abstract
Aptamers are structured nucleic acid molecules that can bind to their targets with high affinity and specificity. However, conventional SELEX (Systematic Evolution of Ligands by EXponential enrichment) methods may not necessarily produce aptamers of desired affinity and specificity. Thus, to address these questions, this perspective is intended to suggest some approaches and tips along with novel selection methods to enhance evolution of aptamers. This perspective covers latest novel innovations as well as a broad range of well-established approaches to improve the individual binding parameters (aptamer affinity, avidity, specificity and/or selectivity) of aptamers during and/or post-SELEX. The advantages and limitations of individual aptamer selection methods and post-SELEX optimizations, along with rational approaches to overcome these limitations are elucidated in each case. Further the impact of chosen selection milieus, linker-systems, aptamer cocktails and detection modules utilized in conjunction with target-specific aptamers, on the overall assay performance are discussed in detail, each with its own advantages and limitations. The simple variations suggested are easily available for facile implementation during and/or post-SELEX to develop ultrasensitive and specific assays. Finally, success studies of established aptamer-based assays are discussed, highlighting how they utilized some of the suggested methodologies to develop commercially successful point-of-care diagnostic assays.
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Affiliation(s)
- Priya Kalra
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Abhijeet Dhiman
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India.,Faculty of Pharmacy, Uttarakhand Technical University, Dehradun, India
| | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong
| | - John G Bruno
- Operational Technologies Corporation, San Antonio, TX, United States
| | - Tarun K Sharma
- Center for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Faridabad, India.,AptaBharat Innovation Private Limited, Translational Health Science and Technology Institute Incubator, Faridabad, India
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73
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Kim M, Kim DM, Kim KS, Jung W, Kim DE. Applications of Cancer Cell-Specific Aptamers in Targeted Delivery of Anticancer Therapeutic Agents. Molecules 2018; 23:E830. [PMID: 29617327 PMCID: PMC6017884 DOI: 10.3390/molecules23040830] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 03/30/2018] [Accepted: 04/02/2018] [Indexed: 02/07/2023] Open
Abstract
Aptamers are single-stranded oligonucleotides that specifically bind and interact with their corresponding targets, including proteins and cells, through unique three-dimensional structures. Numerous aptamers have been developed to target cancer biomarkers with high specificity and affinity, and some are employed as versatile guiding ligands for cancer-specific drug delivery and anti-cancer therapeutics. In this review, we list the aptamers that target tumor surface biomarkers and summarize the representative applications of aptamers as agonists and antagonists that activate anti-cancer and inactivate pro-cancer biomarkers, respectively. In addition, we describe applications of aptamer-drug or aptamer-oligonucleotide conjugates that can deliver therapeutic agents, including small interfering RNAs, micro RNAs, short hairpin RNAs, and chemotherapeutic molecules, to cancer cells. Moreover, we provide examples of aptamer- conjugated nano-vehicles, in which cancer-targeting oligonucleotide aptamers are conjugated with nano-vehicles such as liposomes, micelles, polymeric nanoparticles, and quantum dots. Conjugation of aptamers with anti-cancer drugs and nano-vehicles will facilitate innovative applications of aptamer-based cancer therapeutics.
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Affiliation(s)
- Minhee Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
| | - Dong-Min Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
| | - Keun-Sik Kim
- Department of Biomedical Laboratory Science, Konyang University, Daejeon 35365, Korea.
| | - Woong Jung
- Department of Emergency Medicine Kyung Hee University Hospital at Gangdong, Seoul 05278, Korea.
| | - Dong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
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Oligonucleotide aptamers against tyrosine kinase receptors: Prospect for anticancer applications. Biochim Biophys Acta Rev Cancer 2018; 1869:263-277. [PMID: 29574128 DOI: 10.1016/j.bbcan.2018.03.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 02/07/2023]
Abstract
Transmembrane receptor tyrosine kinases (RTKs) play crucial roles in cancer cell proliferation, survival, migration and differentiation. Area of intense research is searching for effective anticancer therapies targeting these receptors and, to date, several monoclonal antibodies and small-molecule tyrosine kinase inhibitors have entered the clinic. However, some of these drugs show limited efficacy and give rise to acquired resistance. Emerging highly selective compounds for anticancer therapy are oligonucleotide aptamers that interact with their targets by recognizing a specific three-dimensional structure. Because of their nucleic acid nature, the rational design of advanced strategies to manipulate aptamers for both diagnostic and therapeutic applications is greatly simplified over antibodies. In this manuscript, we will provide a comprehensive overview of oligonucleotide aptamers as next generation strategies to efficiently target RTKs in human cancers.
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76
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Yang X, Dinuka Abeydeera N, Liu FW, Egli M. Origins of the enhanced affinity of RNA-protein interactions triggered by RNA phosphorodithioate backbone modification. Chem Commun (Camb) 2017; 53:10508-10511. [PMID: 28868553 PMCID: PMC5608642 DOI: 10.1039/c7cc05722a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The well-characterized interaction between the MS2 coat protein and its cognate RNA hairpin was used to evaluate changes in affinity as a result of phosphorodithioate (PS2) replacing phosphate by biolayer interferometry (BLI). A structure-based analysis of the data provides insights into the origins of the enhanced affinity of RNA-protein interactions triggered by the PS2 moiety.
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Affiliation(s)
- Xianbin Yang
- AM Biotechnologies, LLC, 12521 Gulf Freeway, Houston, TX 77034, USA.
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77
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Abstract
PURPOSE OF REVIEW We will describe recently discovered smart aptamers with tumor specificity, with an emphasis on targeted delivery of novel therapeutic molecules, cancer-specific biomarkers, and immunotherapy. RECENT FINDINGS The development of cancer-specific aptamers has facilitated targeted delivery of potent therapeutic molecules to cancer cells without harming nontumoral cells. This specificity also makes it possible to discover novel cancer biomarkers. Furthermore, alternative immune-checkpoint blockade aptamers have been developed for combinational immunotherapy. SUMMARY Aptamers selected against cancer cells show cancer specificity, which has great potential for targeting. First, functionalizing targeted aptamers with therapeutic molecule payloads (e.g., small activating RNAs, antimitotic drugs, therapeutic antibodies, and peptides) facilitates successful delivery into cancer cells. This approach greatly improves the therapeutic index by minimizing side-effects in nontumoral cells. Second, cancer-specific proteins have been identified as cancer biomarkers through in-vitro and in-vivo selection, aptamer pull-down assays, and mass spectrometry. These newly discovered biomarkers improve therapeutic intervention and diagnostic specificity. In addition, the development of alternative immune-checkpoint blockade aptamers is suggested for use in combinational immunotherapeutic with current immune blockade regimens, to reduce the resistance and exhaustion of T cells in clinical trials. VIDEO ABSTRACT: http://links.lww.com/COON/A21.
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78
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Yang X. Solid-Phase Synthesis of RNA Analogs Containing Phosphorodithioate Linkages. ACTA ACUST UNITED AC 2017; 70:4.77.1-4.77.13. [PMID: 28921494 DOI: 10.1002/cpnc.40] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The oligoribonucleotide phosphorodithioate (PS2-RNA) modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphorodiester backbone linkage. Like a natural phosphodiester RNA backbone linkage, a PS2-modified backbone linkage is achiral at phosphorus. PS2-RNAs are highly stable to nucleases and several in vitro assays have demonstrated their biological activity. For example, PS2-RNAs silenced mRNA in vitro and bound to protein targets in the form of PS2-aptamers (thioaptamers). Thus, the interest in and promise of PS2-RNAs has drawn attention to synthesizing, isolating, and characterizing these compounds. RNA-thiophosphoramidite monomers are commercially available from AM Biotechnologies and this unit describes an effective methodology for solid-phase synthesis, deprotection, and purification of RNAs having PS2 internucleotide linkages. © 2017 by John Wiley & Sons, Inc.
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79
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Selection of PD1/PD-L1 X-Aptamers. Biochimie 2017; 145:125-130. [PMID: 28912094 DOI: 10.1016/j.biochi.2017.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/08/2017] [Indexed: 01/09/2023]
Abstract
Specific, chemically modified aptamers (X-Aptamers) were identified against two immune checkpoint proteins, recombinant Programmed Death 1 (PD-1) and Programmed Death Ligand 1 (PD-L1). Selections were performed using a bead-based X-Aptamer (XA) library containing several different amino acid functional groups attached to dU at the 5-position. The binding affinities and specificities of the selected XA-PD1 and XA-PDL1 were validated by hPD-1 and hPD-L1 expression cells, as well as by binding to human pancreatic ductal adenocarcinoma tissue. The selected PD1 and PDL1 XAs can mimic antibody functions in in vitro assays.
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80
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Chemical Modifications of Nucleic Acid Aptamers for Therapeutic Purposes. Int J Mol Sci 2017; 18:ijms18081683. [PMID: 28767098 PMCID: PMC5578073 DOI: 10.3390/ijms18081683] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 07/27/2017] [Accepted: 08/01/2017] [Indexed: 01/16/2023] Open
Abstract
Nucleic acid aptamers have minimal immunogenicity, high chemical synthesis production, low cost and high chemical stability when compared with antibodies. However, the susceptibility to nuclease degradation, rapid excretion through renal filtration and insufficient binding affinity hindered their development as drug candidates for therapeutic applications. In this review, we will discuss methods to conquer these challenges and highlight recent developments of chemical modifications and technological advances that may enable early aptamers to be translated into clinical therapeutics.
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81
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Volk DE, Lokesh GLR. Development of Phosphorothioate DNA and DNA Thioaptamers. Biomedicines 2017; 5:E41. [PMID: 28703779 PMCID: PMC5618299 DOI: 10.3390/biomedicines5030041] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/03/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023] Open
Abstract
Nucleic acid aptamers are short RNA- or DNA-based affinity reagents typically selected from combinatorial libraries to bind to a specific target such as a protein, a small molecule, whole cells or even animals. Aptamers have utility in the development of diagnostic, imaging and therapeutic applications due to their size, physico-chemical nature and ease of synthesis and modification to suit the application. A variety of oligonucleotide modifications have been used to enhance the stability of aptamers from nuclease degradation in vivo. The non-bridging oxygen atoms of the phosphodiester backbones of RNA and DNA aptamers can be substituted with one or two sulfur atoms, resulting in thioaptamers with phosphorothioate or phosphorodithioate linkages, respectively. Such thioaptamers are known to have increased binding affinity towards their target, as well as enhanced resistance to nuclease degradation. In this review, we discuss the development of phosphorothioate chemistry and thioaptamers, with a brief review of selection methods.
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Affiliation(s)
- David E Volk
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
| | - Ganesh L R Lokesh
- McGovern Medical School, Brown Foundation Institute of Molecular Medicine for the Prevention of Human Diseases, University of Texas Health Science Center, Houston, TX 77030, USA.
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Zhang Q, Lv H, Wang L, Chen M, Li F, Liang C, Yu Y, Jiang F, Lu A, Zhang G. Recent Methods for Purification and Structure Determination of Oligonucleotides. Int J Mol Sci 2016; 17:E2134. [PMID: 27999357 PMCID: PMC5187934 DOI: 10.3390/ijms17122134] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 12/13/2016] [Accepted: 12/14/2016] [Indexed: 12/14/2022] Open
Abstract
Aptamers are single-stranded DNA or RNA oligonucleotides that can interact with target molecules through specific three-dimensional structures. The excellent features, such as high specificity and affinity for target proteins, small size, chemical stability, low immunogenicity, facile chemical synthesis, versatility in structural design and engineering, and accessible for site-specific modifications with functional moieties, make aptamers attractive molecules in the fields of clinical diagnostics and biopharmaceutical therapeutics. However, difficulties in purification and structural identification of aptamers remain a major impediment to their broad clinical application. In this mini-review, we present the recently attractive developments regarding the purification and identification of aptamers. We also discuss the advantages, limitations, and prospects for the major methods applied in purifying and identifying aptamers, which could facilitate the application of aptamers.
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MESH Headings
- Aptamers, Nucleotide/chemistry
- Chromatography, High Pressure Liquid/methods
- Chromatography, Ion Exchange/methods
- Chromatography, Reverse-Phase/methods
- Crystallography, X-Ray/methods
- DNA, Single-Stranded/chemistry
- DNA, Single-Stranded/ultrastructure
- Electrophoresis, Gel, Two-Dimensional/methods
- Nuclear Magnetic Resonance, Biomolecular/methods
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Affiliation(s)
- Qiulong Zhang
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Huanhuan Lv
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Lili Wang
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Man Chen
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Fangfei Li
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Chao Liang
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Yuanyuan Yu
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Feng Jiang
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- The State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Aiping Lu
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
| | - Ge Zhang
- Institute of Integrated Bioinformedicine and Translational Science, School of Chinese Medicine, Hong Kong Baptist University (HKBU), Hong Kong, China.
- Institute of Precision Medicine and Innovative Drug Discovery, HKBU (Haimen) Institute of Science and Technology, Haimen 226100, China.
- Shenzhen Lab of Combinatorial Compounds and Targeted Drug Delivery, HKBU Institute of Research and Continuing Education, Shenzhen 518000, China.
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Lou X, Egli M, Yang X. Determining Functional Aptamer-Protein Interaction by Biolayer Interferometry. ACTA ACUST UNITED AC 2016; 67:7.25.1-7.25.15. [PMID: 27911494 DOI: 10.1002/cpnc.18] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Short single-stranded nucleic acids called aptamers are widely being explored as recognition molecules of high affinity and specificity for binding a wide range of target molecules, particularly protein targets. In biolayer interferometry (BLI), a simple Dip-and-Read approach in which the aptamer-coated biosensors are dipped into microplate wells is used to study the interactions between an aptamer and its target protein. Here we describe the protocol for the analysis of the interaction between a well-characterized anti-thrombin RNA aptamer with thrombin (Basic Protocol). We also report on the protocol for the affinity screening of a panel of anti-thrombin RNA aptamers with a single phosphorodithioate (PS2) modification, whereby the position of the modification along the RNA backbone is varied systematically (Support Protocol). The PS2 modification uses two sulfur atoms to replace two non-bridging oxygen atoms at an internucleotide phosphodiester backbone linkage. The PS2-modified RNAs are nuclease resistant and several in vitro and in vivo assays have demonstrated their biological activity. For example, combining the PS2 with the 2'-OMe modification affords increased loading of modified small interfering RNA (siRNA) duplexes into the RNA-induced silencing complex (RISC) as well as enhanced gene-silencing antitumor activity. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Xinhui Lou
- Department of Chemistry, Capital Normal University, Beijing, China
| | - Martin Egli
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee
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