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Lee M, Shin S, Kim S, Park N. Recent Advances in Biological Applications of Aptamer-Based Fluorescent Biosensors. Molecules 2023; 28:7327. [PMID: 37959747 PMCID: PMC10647268 DOI: 10.3390/molecules28217327] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 10/24/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Aptamers have been spotlighted as promising bio-recognition elements because they can be tailored to specific target molecules, bind to targets with a high affinity and specificity, and are easy to chemically synthesize and introduce functional groups to. In particular, fluorescent aptasensors are widely used in biological applications to diagnose diseases as well as prevent diseases by detecting cancer cells, viruses, and various biomarkers including nucleic acids and proteins as well as biotoxins and bacteria from food because they have the advantages of a high sensitivity, selectivity, rapidity, a simple detection process, and a low price. We introduce screening methods for isolating aptamers with q high specificity and summarize the sequences and affinities of the aptamers in a table. This review focuses on aptamer-based fluorescence detection sensors for biological applications, from fluorescent probes to mechanisms of action and signal amplification strategies.
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Affiliation(s)
- Minhyuk Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea; (M.L.); (S.K.)
| | - Seonhye Shin
- Department of Chemistry, The Natural Science Research Institute, Myongji University, 116 Myongji-ro, Yongin-si 17058, Republic of Korea;
| | - Sungjee Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang 37673, Republic of Korea; (M.L.); (S.K.)
| | - Nokyoung Park
- Department of Chemistry, The Natural Science Research Institute, Myongji University, 116 Myongji-ro, Yongin-si 17058, Republic of Korea;
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Passalacqua LFM, Starich MR, Link KA, Wu J, Knutson JR, Tjandra N, Jaffrey SR, Ferré-D'Amaré AR. Co-crystal structures of the fluorogenic aptamer Beetroot show that close homology may not predict similar RNA architecture. Nat Commun 2023; 14:2969. [PMID: 37221204 PMCID: PMC10205801 DOI: 10.1038/s41467-023-38683-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 05/11/2023] [Indexed: 05/25/2023] Open
Abstract
Beetroot is a homodimeric in vitro selected RNA that binds and activates DFAME, a conditional fluorophore derived from GFP. It is 70% sequence-identical to the previously characterized homodimeric aptamer Corn, which binds one molecule of its cognate fluorophore DFHO at its interprotomer interface. We have now determined the Beetroot-DFAME co-crystal structure at 1.95 Å resolution, discovering that this RNA homodimer binds two molecules of the fluorophore, at sites separated by ~30 Å. In addition to this overall architectural difference, the local structures of the non-canonical, complex quadruplex cores of Beetroot and Corn are distinctly different, underscoring how subtle RNA sequence differences can give rise to unexpected structural divergence. Through structure-guided engineering, we generated a variant that has a 12-fold fluorescence activation selectivity switch toward DFHO. Beetroot and this variant form heterodimers and constitute the starting point for engineered tags whose through-space inter-fluorophore interaction could be used to monitor RNA dimerization.
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Affiliation(s)
- Luiz F M Passalacqua
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Mary R Starich
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Katie A Link
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jiahui Wu
- Department of Pharmacology, Weill-Cornell Medical College, Cornell University, New York, NY, USA
- Department of Chemistry, Binghamton University, Binghamton, NY, 13902, USA
| | - Jay R Knutson
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Nico Tjandra
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill-Cornell Medical College, Cornell University, New York, NY, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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Douaki A, Garoli D, Inam AKMS, Angeli MAC, Cantarella G, Rocchia W, Wang J, Petti L, Lugli P. Smart Approach for the Design of Highly Selective Aptamer-Based Biosensors. BIOSENSORS 2022; 12:bios12080574. [PMID: 36004970 PMCID: PMC9405846 DOI: 10.3390/bios12080574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/23/2022] [Accepted: 07/25/2022] [Indexed: 11/30/2022]
Abstract
Aptamers are chemically synthesized single-stranded DNA or RNA oligonucleotides widely used nowadays in sensors and nanoscale devices as highly sensitive biorecognition elements. With proper design, aptamers are able to bind to a specific target molecule with high selectivity. To date, the systematic evolution of ligands by exponential enrichment (SELEX) process is employed to isolate aptamers. Nevertheless, this method requires complex and time-consuming procedures. In silico methods comprising machine learning models have been recently proposed to reduce the time and cost of aptamer design. In this work, we present a new in silico approach allowing the generation of highly sensitive and selective RNA aptamers towards a specific target, here represented by ammonium dissolved in water. By using machine learning and bioinformatics tools, a rational design of aptamers is demonstrated. This “smart” SELEX method is experimentally proved by choosing the best five aptamer candidates obtained from the design process and applying them as functional elements in an electrochemical sensor to detect, as the target molecule, ammonium at different concentrations. We observed that the use of five different aptamers leads to a significant difference in the sensor’s response. This can be explained by considering the aptamers’ conformational change due to their interaction with the target molecule. We studied these conformational changes using a molecular dynamics simulation and suggested a possible explanation of the experimental observations. Finally, electrochemical measurements exposing the same sensors to different molecules were used to confirm the high selectivity of the designed aptamers. The proposed in silico SELEX approach can potentially reduce the cost and the time needed to identify the aptamers and potentially be applied to any target molecule.
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Affiliation(s)
- Ali Douaki
- Faculty of Science and Technology, Libera Università di Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (A.K.M.S.I.); (M.A.C.A.); (G.C.); (L.P.)
- Correspondence: (A.D.); (P.L.)
| | - Denis Garoli
- Istituto Italiano di Tecnologia, Via Morego, 30, 16163 Genova, Italy;
| | - A. K. M. Sarwar Inam
- Faculty of Science and Technology, Libera Università di Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (A.K.M.S.I.); (M.A.C.A.); (G.C.); (L.P.)
| | - Martina Aurora Costa Angeli
- Faculty of Science and Technology, Libera Università di Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (A.K.M.S.I.); (M.A.C.A.); (G.C.); (L.P.)
| | - Giuseppe Cantarella
- Faculty of Science and Technology, Libera Università di Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (A.K.M.S.I.); (M.A.C.A.); (G.C.); (L.P.)
| | - Walter Rocchia
- CONCEPT Lab, Istituto Italiano di Tecnologia, Via Enrico Melen 83, 16152 Genova, Italy;
| | - Jiahai Wang
- School of Mechanical and Electrical Engineering, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China;
| | - Luisa Petti
- Faculty of Science and Technology, Libera Università di Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (A.K.M.S.I.); (M.A.C.A.); (G.C.); (L.P.)
| | - Paolo Lugli
- Faculty of Science and Technology, Libera Università di Bolzano, Piazza Università 1, 39100 Bolzano, Italy; (A.K.M.S.I.); (M.A.C.A.); (G.C.); (L.P.)
- Correspondence: (A.D.); (P.L.)
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Sanford AA, Manuel BA, Romero-Reyes MA, Heemstra JM. Combating small molecule environmental contaminants: detection and sequestration using functional nucleic acids. Chem Sci 2022; 13:7670-7684. [PMID: 35865900 PMCID: PMC9258336 DOI: 10.1039/d2sc00117a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/26/2022] [Indexed: 12/05/2022] Open
Abstract
Small molecule contaminants pose a significant threat to the environment and human health. While regulations are in place for allowed limits in many countries, detection and remediation of contaminants in more resource-limited settings and everyday environmental sources remains a challenge. Functional nucleic acids, including aptamers and DNA enzymes, have emerged as powerful options for addressing this challenge due to their ability to non-covalently interact with small molecule targets. The goal of this perspective is to outline recent efforts toward the selection of aptamers for small molecules and describe their subsequent implementation for environmental applications. Finally, we provide an outlook that addresses barriers that hinder these technologies from being widely adopted in field friendly settings and propose a path forward toward addressing these challenges.
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Affiliation(s)
- Aimee A Sanford
- Department of Chemistry, Emory University Atlanta Georgia 30322 USA
| | - Brea A Manuel
- Department of Chemistry, Emory University Atlanta Georgia 30322 USA
| | - Misael A Romero-Reyes
- Department of Chemistry, Emory University Atlanta Georgia 30322 USA
- Department of Chemistry, Hanover College Hanover Indiana 47243 USA
| | - Jennifer M Heemstra
- Department of Chemistry, Emory University Atlanta Georgia 30322 USA
- Department of Biomedical Engineering, Georgia Institute of Technology, Emory University Atlanta GA 30332 USA
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The fluorescent aptamer Squash extensively repurposes the adenine riboswitch fold. Nat Chem Biol 2022; 18:191-198. [PMID: 34937911 PMCID: PMC9812287 DOI: 10.1038/s41589-021-00931-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 10/21/2021] [Indexed: 01/07/2023]
Abstract
Squash is an RNA aptamer that strongly activates the fluorescence of small-molecule analogs of the fluorophore of green fluorescent protein (GFP). Unlike other fluorogenic aptamers, isolated de novo from random-sequence RNA, Squash was evolved from the bacterial adenine riboswitch to leverage its optimized in vivo folding and stability. We now report the 2.7-Å resolution cocrystal structure of fluorophore-bound Squash, revealing that while the overall fold of the riboswitch is preserved, the architecture of the ligand-binding core is dramatically transformed. Unlike previously characterized aptamers that activate GFP-derived fluorophores, Squash does not harbor a G-quadruplex, sandwiching its fluorophore between a base triple and a noncanonical base quadruple in a largely apolar pocket. The expanded structural core of Squash allows it to recognize unnatural fluorophores that are larger than the simple purine ligand of the parental adenine riboswitch, and suggests that stable RNA scaffolds can tolerate larger variation than has hitherto been appreciated.
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