1
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Lu X, Passalacqua LFM, Nodwell M, Kong KYS, Caballero-García G, Dolgosheina EV, Ferré-D'Amaré AR, Britton R, Unrau PJ. Symmetry breaking of fluorophore binding to a G-quadruplex generates an RNA aptamer with picomolar KD. Nucleic Acids Res 2024; 52:8039-8051. [PMID: 38945550 DOI: 10.1093/nar/gkae493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/21/2024] [Accepted: 06/12/2024] [Indexed: 07/02/2024] Open
Abstract
Fluorogenic RNA aptamer tags with high affinity enable RNA purification and imaging. The G-quadruplex (G4) based Mango (M) series of aptamers were selected to bind a thiazole orange based (TO1-Biotin) ligand. Using a chemical biology and reselection approach, we have produced a MII.2 aptamer-ligand complex with a remarkable set of properties: Its unprecedented KD of 45 pM, formaldehyde resistance (8% v/v), temperature stability and ligand photo-recycling properties are all unusual to find simultaneously within a small RNA tag. Crystal structures demonstrate how MII.2, which differs from MII by a single A23U mutation, and modification of the TO1-Biotin ligand to TO1-6A-Biotin achieves these results. MII binds TO1-Biotin heterogeneously via a G4 surface that is surrounded by a stadium of five adenosines. Breaking this pseudo-rotational symmetry results in a highly cooperative and homogeneous ligand binding pocket: A22 of the G4 stadium stacks on the G4 binding surface while the TO1-6A-Biotin ligand completely fills the remaining three quadrants of the G4 ligand binding face. Similar optimization attempts with MIII.1, which already binds TO1-Biotin in a homogeneous manner, did not produce such marked improvements. We use the novel features of the MII.2 complex to demonstrate a powerful optically-based RNA purification system.
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Affiliation(s)
- Xiaocen Lu
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Luiz F M Passalacqua
- Laboratory of Nucleic Acids, National Heart, Lung and Blood Institute, Bethesda, MD 20892, USA
| | - Matthew Nodwell
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Kristen Y S Kong
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | | | - Elena V Dolgosheina
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Adrian R Ferré-D'Amaré
- Laboratory of Nucleic Acids, National Heart, Lung and Blood Institute, Bethesda, MD 20892, USA
| | - Robert Britton
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Peter J Unrau
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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2
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Jiang L, Teng J, Liu X, Xu L, Yang T, Hu X, Ding S, Li J, Jiang Y, Cheng W. Interaction analysis of RNA G-quadruplex with ligands and in situ imaging application. Anal Biochem 2024; 694:115613. [PMID: 39002744 DOI: 10.1016/j.ab.2024.115613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2024] [Revised: 06/09/2024] [Accepted: 07/10/2024] [Indexed: 07/15/2024]
Abstract
RNA G4, as an integral branch of G4 structure, possesses distinct interactions with ligands compared to the common DNA G4, thus the investigation of RNA G4/ligand interactions might be considered as a fresh breakthrough to improve the biosensing performance of G4/ligand system. In this study, we comparatively explored the structural and functional mechanisms of RNA G4 and DNA G4 in the interaction with ligands, hemin and thioflavin T (ThT), utilizing the classical PS2.M sequence as a model. We found that although the catalytic performance of RNA G4/hemin system was lower than DNA G4/hemin, RNA G4/ThT fluorescence system exhibited a significant improvement (2∼3-fold) compared to DNA G4/ThT, and adenine modification could further enhance the signaling. Further, by exploring the interaction between RNA G4 and ThT, we deemed that RNA G4 and ThT were stacked in a bimolecular mode compared to single-molecule binding of DNA G4/ThT, thus more strongly limiting the structural spin in ThT excited state. Further, RNA G4/ThT displayed higher environmental tolerance and lower ion dependence than DNA G4/ThT. Finally, we employed RNA G4/ThT as a highly sensitive label-free fluorescent signal output system for in situ imaging of isoforms BCR-ABL e13a2 and e14a2. Overall, this study successfully screened a high-performance RNA G4 biosensing system through systematic RNA G4/ligands interaction studies, which was expected to provide a promising reference for subsequent G4/ligand research.
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Affiliation(s)
- Lanxin Jiang
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Jie Teng
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China; Department of Laboratory Medicine, West China Second Hospital of Sichuan University, Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, 610066, PR China
| | - Xiaojuan Liu
- Department of Laboratory Medicine, West China Second Hospital of Sichuan University, Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, 610066, PR China
| | - Lulu Xu
- Department of Laboratory Medicine, Shandong Provincial Hospital Affiliated to Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, Shandong, PR China
| | - Tiantian Yang
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Xingping Hu
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China
| | - Shijia Ding
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, PR China
| | - Jia Li
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China.
| | - Yongmei Jiang
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China.
| | - Wei Cheng
- The Center for Clinical Molecular Medical Detection, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China; Biobank Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, PR China.
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3
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Farag M, Mouawad L. Comprehensive analysis of intramolecular G-quadruplex structures: furthering the understanding of their formalism. Nucleic Acids Res 2024; 52:3522-3546. [PMID: 38512075 DOI: 10.1093/nar/gkae182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 02/16/2024] [Accepted: 03/01/2024] [Indexed: 03/22/2024] Open
Abstract
G-quadruplexes (G4) are helical structures found in guanine-rich DNA or RNA sequences. Generally, their formalism is based on a few dozen structures, which can produce some inconsistencies or incompleteness. Using the website ASC-G4, we analyzed the structures of 333 intramolecular G4s, of all types, which allowed us to clarify some key concepts and present new information. To each of the eight distinguishable topologies corresponds a groove-width signature and a predominant glycosidic configuration (gc) pattern governed by the directions of the strands. The relative orientations of the stacking guanines within the strands, which we quantified and related to their vertical gc successions, determine the twist and tilt of the helices. The latter impact the minimum groove widths, which represent the space available for lateral ligand binding. The G4 four helices have similar twists, even when these twists are irregular, meaning that they have various angles along the strands. Despite its importance, the vertical gc succession has no strict one-to-one relationship with the topology, which explains the discrepancy between some topologies and their corresponding circular dichroism spectra. This study allowed us to introduce the new concept of platypus G4s, which are structures with properties corresponding to several topologies.
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Affiliation(s)
- Marc Farag
- Chemistry and Modeling for the Biology of Cancer, CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, CS 90030, 91401 ORSAYCedex, France
| | - Liliane Mouawad
- Chemistry and Modeling for the Biology of Cancer, CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, Université Paris-Saclay, CS 90030, 91401 ORSAYCedex, France
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4
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Doğan K, Ünal Taş D, Persil Çetinkol Ö, Forough M. Fluorometric and colorimetric platforms for rapid and sensitive hydroxychloroquine detection in aqueous samples. Talanta 2024; 270:125523. [PMID: 38101033 DOI: 10.1016/j.talanta.2023.125523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 12/17/2023]
Abstract
The detection of pharmaceuticals has been an active area of research with numerous application areas ranging from therapeutic and environmental monitoring to pharmaceutical manufacturing and diagnostics. And, the emergence of COVID-19 pandemic has increased the demand for detection of certain active pharmaceutical ingredients such as Hydroxychloroquine (HCQ) mainly due to their increased manufacturing and usage. In this study, we present two optical, fluorometric and colorimetric, detection platforms for the rapid and sensitive detection of HCQ. These platforms take advantage of the interactions between the highly fluorescent dye Thioflavin T (ThT) and Tel24 G-quadruplex (G4) DNA structure, as well as the salt-induced aggregation behavior of negatively charged citrate-capped silver nanoparticles (Cit-AgNPs) in the presence of HCQ. In the fluorometric method, the addition of HCQ led to a significant and rapid decrease in the fluorescence signal of the ThT + Tel24 probe. In the colorimetric method, HCQ induced the aggregation of Cit-AgNPs in the presence of NaCl, resulting in a noticeable color change from yellowish-gray to colorless. Under the optimized conditions, the colorimetric platform exhibited a linear range of 18.0-240.0 nM and a detection limit of 9.2 nM, while the fluorometric platform showed a linear range of 0.24-5.17 μM and a detection limit of 120 nM. The selectivity of the proposed optical methods towards the target analyte was demonstrated by evaluating the response to other structurally similar small molecules. Finally, the practical applicability of both detection systems was confirmed by analyzing HCQ-spiked human urine samples that yielded average recoveries ranging from 75.4 to 110.2 % for the fluorometric platform and 86.9-98.2 % for the colorimetric platform. These results indicate the potential of the developed methods for HCQ detection in complex matrices.
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Affiliation(s)
- Kübra Doğan
- Department of Chemistry, Middle East Technical University, 06800, Çankaya, Ankara, Turkey
| | - Dilek Ünal Taş
- Department of Chemistry, Middle East Technical University, 06800, Çankaya, Ankara, Turkey
| | - Özgül Persil Çetinkol
- Department of Chemistry, Middle East Technical University, 06800, Çankaya, Ankara, Turkey
| | - Mehrdad Forough
- Department of Chemistry, Middle East Technical University, 06800, Çankaya, Ankara, Turkey.
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5
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Wu Q, Tian F, Chen W, Wang J, Lei B. Specific Recognition and Adsorption of Volatile Organic Compounds by Using MIL-125-Based Porous Fluorescence Probe Material. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2732. [PMID: 37836373 PMCID: PMC10574030 DOI: 10.3390/nano13192732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/26/2023] [Accepted: 07/26/2023] [Indexed: 10/15/2023]
Abstract
The severity of the volatile organic compounds (VOCs) issue calls for effective detection and management of VOC materials. Metal-organic frameworks (MOFs) are organic-inorganic hybrid crystals with promising prospects in luminescent sensing for VOC detection and identification. However, MOFs have limitations, including weak response signals and poor sensitivity towards VOCs, limiting their application to specific types of VOC gases. To address the issue of limited recognition and single luminosity for specific VOCs, we have introduced fluorescent guest molecules into MOFs as reference emission centers to enhance sensitivity. This composite material combines the gas adsorption ability of MOFs to effectively adsorb VOCs. We utilized (MIL-125/NH2-MIL-125) as the parent material for adsorbing fluorescent molecules and selected suitable solid fluorescent probes (FGFL-B1) through fluorescence enhancement using thioflavin T and MIL-125. FGFL-B1 exhibited a heightened fluorescence response to various VOCs through charge transfer between fluorescent guest molecules and ligands. The fluorescence enhancement effect of FGFL-B1 on tetrahydrofuran (THF) was particularly pronounced, accompanied by a color change from yellow to yellowish green in the presence of CCl4. FGFL-B1 demonstrated excellent adsorption properties for THF and CCl4, with saturated adsorption capacities of 655.4 mg g-1 and 811.2 mg g-1, respectively. Furthermore, FGFL-B1 displayed strong luminescence stability and reusability, making it an excellent sensing candidate. This study addresses the limitations of MOFs in VOC detection, opening avenues for industrial and environmental applications.
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Affiliation(s)
| | | | - Wenqian Chen
- Key Laboratory of Organic Compound Pollution Control Engineering, Ministry of Education, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China; (Q.W.); (F.T.)
| | - Jianying Wang
- Key Laboratory of Organic Compound Pollution Control Engineering, Ministry of Education, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China; (Q.W.); (F.T.)
| | - Bo Lei
- Key Laboratory of Organic Compound Pollution Control Engineering, Ministry of Education, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China; (Q.W.); (F.T.)
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6
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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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7
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Chen K, Zhu L, Du Z, Lan X, Huang K, Zhang W, Xu W. Docking-aided rational tailoring of a fluorescence- and affinity-enhancing aptamer for a label-free ratiometric malachite green point-of-care aptasensor. JOURNAL OF HAZARDOUS MATERIALS 2023; 447:130798. [PMID: 36669418 DOI: 10.1016/j.jhazmat.2023.130798] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/12/2023] [Accepted: 01/13/2023] [Indexed: 06/17/2023]
Abstract
Although nucleic acid aptasensors are increasingly applied in the detection of environmentally hazardous biomolecules, several formidable challenges remain with this technique because of their vulnerability, high cost and suboptimal sensitivity. Here, a docking-aided rational tailoring (DART) strategy was established at three levels and in two dimensions for the refinement of malachite green (MG) DNA aptamers. Guided by in silico molecular docking, coarse and fine tailoring were conducted at three levels each, to significantly enhance fluorescence activation intensity and binding affinity in two dimensions. Empowered by the results of the rational tailoring, a mechanistic view of the MG DNA aptamer-target interaction was thoroughly analyzed via four types of interactions. To meet the demand for point-of-care testing (POCT), a label-free and ratiometric fluorescent aptasensor was developed leveraging the tailored MG aptamer, based on the binding site competition-equilibrium effect via the introduction of a reference dye. This sensitive, specific, low-cost and rapid aptasensor subsequently demonstrated outstanding detection performance, achieving an ideal signal response range of 5 nmol·L-1 - 6 μmol·L-1 and a low limit of detection (LOD) of 1.49 nmol·L-1. The DART strategy and systematic exploration of the MG DNA luminescent aptamers herein will provide a valuable reference in the field of aptamer tailoring, biosensing and bioimaging. The proposed label-free ratiometric aptasensor also provides a highly generalizable strategy for hazardous biomolecular detection.
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Affiliation(s)
- Keren Chen
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Longjiao Zhu
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Zaihui Du
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Xinyue Lan
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Kunlun Huang
- Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China
| | - Wenqiang Zhang
- Department of Mechanical Design and Manufacturing, College of Engineering, China Agricultural University, Beijing 100083, China
| | - Wentao Xu
- Food Laboratory of Zhongyuan, Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing 100193, China; Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
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8
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Yan S, Ilgu M, Nilsen-Hamilton M, Lamm MH. Computational Modeling of RNA Aptamers: Structure Prediction of the Apo State. J Phys Chem B 2022; 126:7114-7125. [PMID: 36097649 PMCID: PMC9512008 DOI: 10.1021/acs.jpcb.2c04649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/23/2022] [Indexed: 11/28/2022]
Abstract
RNA aptamers are single-stranded oligonucleotides that bind to specific molecular targets with high affinity and specificity. To design aptamers for new applications, it is critical to understand the ligand binding mechanism in terms of the structure and dynamics of the ligand-bound and apo states. The problem is that most of the NMR or X-ray crystal structures available for RNA aptamers are for ligand-bound states. Available apo state structures, mostly characterized by crystallization under nonphysiological conditions or probed by low resolution techniques, might fail to represent the diverse structural variations of the apo state in solution. Here, we develop an approach to obtain a representative ensemble of apo structures that are based on in silico RNA 3D structure prediction and in vitro experiments that characterize base stacking. Using the neomycin-B aptamer as a case study, an ensemble of structures for the aptamer in the apo (unbound) state are validated and then used to investigate the ligand-binding mechanism for the aptamer in complex with neomycin-B.
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Affiliation(s)
- Shuting Yan
- Iowa
State University, Ames, Iowa 50011, United States
| | - Muslum Ilgu
- Iowa
State University, Ames, Iowa 50011, United States
- Ames
National Laboratory, Ames, Iowa 50011, United States
- Aptalogic
Inc., Ames, Iowa 50014, United States
| | - Marit Nilsen-Hamilton
- Iowa
State University, Ames, Iowa 50011, United States
- Ames
National Laboratory, Ames, Iowa 50011, United States
- Aptalogic
Inc., Ames, Iowa 50014, United States
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9
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Hu X, Tang L, Zheng M, Liu J, Zhang Z, Li Z, Yang Q, Xiang S, Fang L, Ren Q, Liu X, Huang CZ, Mao C, Zuo H. Structure-Guided Designing Pre-Organization in Bivalent Aptamers. J Am Chem Soc 2022; 144:4507-4514. [PMID: 35245025 DOI: 10.1021/jacs.1c12593] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Multivalent interaction is often used in molecular design and leads to engineered multivalent ligands with increased binding avidities toward target molecules. The resulting binding avidity relies critically on the rigid scaffold that joins multiple ligands as the scaffold controls the relative spatial positions and orientations toward target molecules. Currently, no general design rules exist to construct a simple and rigid DNA scaffold for properly joining multiple ligands. Herein, we report a crystal structure-guided strategy for the rational design of a rigid bivalent aptamer with precise control over spatial separation and orientation. Such a pre-organization allows the two aptamer moieties simultaneously to bind to the target protein at their native conformations. The bivalent aptamer binding has been extensively characterized, and an enhanced binding has been clearly observed. This strategy, we believe, could potentially be generally applicable to design multivalent aptamers.
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Affiliation(s)
- Xiaoli Hu
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Linlin Tang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Mengxi Zheng
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Jian Liu
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Zhe Zhang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Zhe Li
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Quan Yang
- Department of Cardiology, The Fourth People's Hospital of Sichuan Province, Chengdu 610016, China
| | - Shoubo Xiang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Liang Fang
- Department of Oncology, The Ninth People's Hospital of Chongqing, Chongqing 400700, China
| | - Qiao Ren
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Xuemei Liu
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Cheng Zhi Huang
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
| | - Chengde Mao
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China.,Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hua Zuo
- Key Laboratory of Luminescence Analysis and Molecular Sensing (Southwest University), Ministry of Education, College of Pharmaceutical Sciences, Southwest University, Chongqing 400715, China
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10
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Víglaský V. Hidden Information Revealed Using the Orthogonal System of Nucleic Acids. Int J Mol Sci 2022; 23:ijms23031804. [PMID: 35163723 PMCID: PMC8836696 DOI: 10.3390/ijms23031804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 11/25/2022] Open
Abstract
In this study, the organization of genetic information in nucleic acids is defined using a novel orthogonal representation. Clearly defined base pairing in DNA allows the linear base chain and sequence to be mathematically transformed into an orthogonal representation where the G–C and A–T pairs are displayed in different planes that are perpendicular to each other. This form of base allocation enables the evaluation of any nucleic acid and predicts the likelihood of a particular region to form non-canonical motifs. The G4Hunter algorithm is currently a popular method of identifying G-quadruplex forming sequences in nucleic acids, and offers promising scores despite its lack of a substantial rational basis. The orthogonal representation described here is an effort to address this incongruity. In addition, the orthogonal display facilitates the search for other sequences that are capable of adopting non-canonical motifs, such as direct and palindromic repeats. The technique can also be used for various RNAs, including any aptamers. This powerful tool based on an orthogonal system offers considerable potential for a wide range of applications.
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Affiliation(s)
- Viktor Víglaský
- Department of Biochemistry, Institute of Chemistry, Faculty of Sciences, Pavol Jozef Šafárik University, 04001 Košice, Slovakia
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11
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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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Skeparnias I, Zhang J. Cooperativity and Interdependency between RNA Structure and RNA-RNA Interactions. Noncoding RNA 2021; 7:ncrna7040081. [PMID: 34940761 PMCID: PMC8704770 DOI: 10.3390/ncrna7040081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
Complex RNA–RNA interactions are increasingly known to play key roles in numerous biological processes from gene expression control to ribonucleoprotein granule formation. By contrast, the nature of these interactions and characteristics of their interfaces, especially those that involve partially or wholly structured RNAs, remain elusive. Herein, we discuss different modalities of RNA–RNA interactions with an emphasis on those that depend on secondary, tertiary, or quaternary structure. We dissect recently structurally elucidated RNA–RNA complexes including RNA triplexes, riboswitches, ribozymes, and reverse transcription complexes. These analyses highlight a reciprocal relationship that intimately links RNA structure formation with RNA–RNA interactions. The interactions not only shape and sculpt RNA structures but also are enabled and modulated by the structures they create. Understanding this two-way relationship between RNA structure and interactions provides mechanistic insights into the expanding repertoire of noncoding RNA functions, and may inform the design of novel therapeutics that target RNA structures or interactions.
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Rhodamine 6G-Ligand Influencing G-Quadruplex Stability and Topology. Int J Mol Sci 2021; 22:ijms22147639. [PMID: 34299257 PMCID: PMC8305571 DOI: 10.3390/ijms22147639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Revised: 07/09/2021] [Accepted: 07/15/2021] [Indexed: 11/17/2022] Open
Abstract
The involvement of G-quadruplex (G4) structures in nucleic acids in various molecular processes in cells such as replication, gene-pausing, the expression of crucial cancer-related genes and DNA damage repair is well known. The compounds targeting G4 usually bind directly to the G4 structure, but some ligands can also facilitate the G4 folding of unfolded G-rich sequences and stabilize them even without the presence of monovalent ions such as sodium or potassium. Interestingly, some G4-ligand complexes can show a clear induced CD signal, a feature which is indirect proof of the ligand interaction. Based on the dichroic spectral profile it is not only possible to confirm the presence of a G4 structure but also to determine its topology. In this study we examine the potential of the commercially available Rhodamine 6G (RhG) as a G4 ligand. RhG tends to convert antiparallel G4 structures to parallel forms in a manner similar to that of Thiazole Orange. Our results confirm the very high selectivity of this ligand to the G4 structure. Moreover, the parallel topology of G4 can be verified unambiguously based on the specific induced CD profile of the G4-RhG complex. This feature has been verified on more than 50 different DNA sequences forming various non-canonical structural motifs.
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Verma S, Ravichandiran V, Ranjan N. Beyond amyloid proteins: Thioflavin T in nucleic acid recognition. Biochimie 2021; 190:111-123. [PMID: 34118329 DOI: 10.1016/j.biochi.2021.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 05/25/2021] [Accepted: 06/04/2021] [Indexed: 01/01/2023]
Abstract
Thioflavin T (ThT) is a commercially available fluorescent dye that is commonly used in biomedical research for over five decades. It was first reported as an extrinsic fluorescent probe for the detection of amyloid fibrils and related processes and it has also been used extensively for assessing protein binding in fluorescence-based assays. Although the nucleic acid binding of ThT was reported half of a century ago in the 1970s, it was not widely explored until the start of this decade. In recent years, Thioflavin T has become a major tool in the recognition of many types of non-canonical nucleic acid conformations including duplexes, triplexes, and G-quadruplexes. The propensity of ThT binding is more towards base aberrations, bulges, and mismatches highlighting its importance in serving as a diagnostic tool in a variety of ailments/disease conditions. In this review, we cover major advancements in nucleic acid detection/binding by ThT to a variety of nucleic acid structures.
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Affiliation(s)
- Smita Verma
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER)-Raebareli, New Transit Campus, Lucknow, Uttar Pradesh, 226002, India; Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Maniktala Main Road, Kolkata, 700054, India
| | - Velayutham Ravichandiran
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Maniktala Main Road, Kolkata, 700054, India
| | - Nihar Ranjan
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER)-Raebareli, New Transit Campus, Lucknow, Uttar Pradesh, 226002, India.
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Banco MT, Ferré-D'Amaré AR. The emerging structural complexity of G-quadruplex RNAs. RNA (NEW YORK, N.Y.) 2021; 27:390-402. [PMID: 33483368 PMCID: PMC7962482 DOI: 10.1261/rna.078238.120] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
G-quadruplexes (G4s) are four-stranded nucleic acid structures that arise from the stacking of G-quartets, cyclic arrangements of four guanines engaged in Hoogsteen base-pairing. Until recently, most RNA G4 structures were thought to conform to a sequence pattern in which guanines stacking within the G4 would also be contiguous in sequence (e.g., four successive guanine trinucleotide tracts separated by loop nucleotides). Such a sequence restriction, and the stereochemical constraints inherent to RNA (arising, in particular, from the presence of the 2'-OH), dictate relatively simple RNA G4 structures. Recent crystallographic and solution NMR structure determinations of a number of in vitro selected RNA aptamers have revealed RNA G4 structures of unprecedented complexity. Structures of the Sc1 aptamer that binds an RGG peptide from the Fragile-X mental retardation protein, various fluorescence turn-on aptamers (Corn, Mango, and Spinach), and the spiegelmer that binds the complement protein C5a, in particular, reveal complexity hitherto unsuspected in RNA G4s, including nucleotides in syn conformation, locally inverted strand polarity, and nucleotide quartets that are not all-G. Common to these new structures, the sequences folding into G4s do not conform to the requirement that guanine stacks arise from consecutive (contiguous in sequence) nucleotides. This review highlights how emancipation from this constraint drastically expands the structural possibilities of RNA G-quadruplexes.
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Affiliation(s)
- Michael T Banco
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-8012, USA
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung, and Blood Institute, Bethesda, Maryland 20892-8012, USA
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Zsila F, Samsonov SA, Maszota-Zieleniak M. Mind Your Dye: The Amyloid Sensor Thioflavin T Interacts with Sulfated Glycosaminoglycans Used To Induce Cross-β-Sheet Motifs. J Phys Chem B 2020; 124:11625-11633. [DOI: 10.1021/acs.jpcb.0c08273] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Ferenc Zsila
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - Sergey A. Samsonov
- Faculty of Chemistry, University of Gdańsk, ul. Wita Stwosza 63, 80-308 Gdańsk, Poland
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Micura R, Höbartner C. Fundamental studies of functional nucleic acids: aptamers, riboswitches, ribozymes and DNAzymes. Chem Soc Rev 2020; 49:7331-7353. [PMID: 32944725 DOI: 10.1039/d0cs00617c] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This review aims at juxtaposing common versus distinct structural and functional strategies that are applied by aptamers, riboswitches, and ribozymes/DNAzymes. Focusing on recently discovered systems, we begin our analysis with small-molecule binding aptamers, with emphasis on in vitro-selected fluorogenic RNA aptamers and their different modes of ligand binding and fluorescence activation. Fundamental insights are much needed to advance RNA imaging probes for detection of exo- and endogenous RNA and for RNA process tracking. Secondly, we discuss the latest gene expression-regulating mRNA riboswitches that respond to the alarmone ppGpp, to PRPP, to NAD+, to adenosine and cytidine diphosphates, and to precursors of thiamine biosynthesis (HMP-PP), and we outline new subclasses of SAM and tetrahydrofolate-binding RNA regulators. Many riboswitches bind protein enzyme cofactors that, in principle, can catalyse a chemical reaction. For RNA, however, only one system (glmS ribozyme) has been identified in Nature thus far that utilizes a small molecule - glucosamine-6-phosphate - to participate directly in reaction catalysis (phosphodiester cleavage). We wonder why that is the case and what is to be done to reveal such likely existing cellular activities that could be more diverse than currently imagined. Thirdly, this brings us to the four latest small nucleolytic ribozymes termed twister, twister-sister, pistol, and hatchet as well as to in vitro selected DNA and RNA enzymes that promote new chemistry, mainly by exploiting their ability for RNA labelling and nucleoside modification recognition. Enormous progress in understanding the strategies of nucleic acids catalysts has been made by providing thorough structural fundaments (e.g. first structure of a DNAzyme, structures of ribozyme transition state mimics) in combination with functional assays and atomic mutagenesis.
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Affiliation(s)
- Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University Innsbruck, Innsbruck, Austria.
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Structural Insights into RNA Dimerization: Motifs, Interfaces and Functions. Molecules 2020; 25:molecules25122881. [PMID: 32585844 PMCID: PMC7357161 DOI: 10.3390/molecules25122881] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/26/2022] Open
Abstract
In comparison with the pervasive use of protein dimers and multimers in all domains of life, functional RNA oligomers have so far rarely been observed in nature. Their diminished occurrence contrasts starkly with the robust intrinsic potential of RNA to multimerize through long-range base-pairing ("kissing") interactions, self-annealing of palindromic or complementary sequences, and stable tertiary contact motifs, such as the GNRA tetraloop-receptors. To explore the general mechanics of RNA dimerization, we performed a meta-analysis of a collection of exemplary RNA homodimer structures consisting of viral genomic elements, ribozymes, riboswitches, etc., encompassing both functional and fortuitous dimers. Globally, we found that domain-swapped dimers and antiparallel, head-to-tail arrangements are predominant architectural themes. Locally, we observed that the same structural motifs, interfaces and forces that enable tertiary RNA folding also drive their higher-order assemblies. These feature prominently long-range kissing loops, pseudoknots, reciprocal base intercalations and A-minor interactions. We postulate that the scarcity of functional RNA multimers and limited diversity in multimerization motifs may reflect evolutionary constraints imposed by host antiviral immune surveillance and stress sensing. A deepening mechanistic understanding of RNA multimerization is expected to facilitate investigations into RNA and RNP assemblies, condensates, and granules and enable their potential therapeutical targeting.
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In-Gel Probing Polymorphic Structures of G-Quadruplexes Derived from c-Myc Promoter. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2020. [DOI: 10.1016/s1872-2040(20)60002-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Dhamodharan V, Pradeepkumar PI. Specific Recognition of Promoter G-Quadruplex DNAs by Small Molecule Ligands and Light-up Probes. ACS Chem Biol 2019; 14:2102-2114. [PMID: 31532996 DOI: 10.1021/acschembio.9b00475] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
G-Quadruplexes (G4s) are four-stranded nucleic acid structures whose underlying G-rich sequences are present across the chromosome and transcriptome. These highly structured elements are known to regulate many key biological functions such as replication, transcription, translation, and genomic stability, thereby providing an additional layer of gene regulation. G4s are structurally dynamic and diverse, and they can fold into numerous topologies. They are potential targets for small molecules, which can modulate their functions. To this end, myriad classes of small molecules have been developed and studied for their ability to bind and stabilize these unique structures. Though many of them can selectively target G4s over duplex DNA, only a few of them can distinguish one G4 topology from others. Design and development of G4-specific ligands are challenging owing to the subtle structural variations among G4 structures. However, screening assays and computational methods have identified a few classes of ligands that preferentially or specifically target the G4 topology of interest over others. This review focuses on the small molecules and fluorescent probes that specifically target human promoter G4s associated with oncogenes. Targeting promoter G4s could circumvent the issues such as undruggability and development of drug resistance associated with the protein targets. The ligands discussed here highlight that development of G4-specific ligands is an achievable goal in spite of the limited structural data available. The future goal is to pursue the development of G4-specific ligands endowed with drug-like properties for G4-based therapeutics and diagnostics.
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Affiliation(s)
- V. Dhamodharan
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
- Okinawa Institute of Science and Technology Graduate University, Okinawa 9040495, Japan
| | - P. I. Pradeepkumar
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai 400076, India
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Tracking RNA with light: selection, structure, and design of fluorescence turn-on RNA aptamers. Q Rev Biophys 2019; 52:e8. [PMID: 31423956 DOI: 10.1017/s0033583519000064] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Fluorescence turn-on aptamers, in vitro evolved RNA molecules that bind conditional fluorophores and activate their fluorescence, have emerged as RNA counterparts of the fluorescent proteins. Turn-on aptamers have been selected to bind diverse fluorophores, and they achieve varying degrees of specificity and affinity. These RNA-fluorophore complexes, many of which exceed the brightness of green fluorescent protein and their variants, can be used as tags for visualizing RNA localization and transport in live cells. Structure determination of several fluorescent RNAs revealed that they have diverse, unrelated overall architectures. As most of these RNAs activate the fluorescence of their ligands by restraining their photoexcited states into a planar conformation, their fluorophore binding sites have in common a planar arrangement of several nucleobases, most commonly a G-quartet. Nonetheless, each turn-on aptamer has developed idiosyncratic structural solutions to achieve specificity and efficient fluorescence turn-on. The combined structural diversity of fluorophores and turn-on RNA aptamers has already produced combinations that cover the visual spectrum. Further molecular evolution and structure-guided engineering is likely to produce fluorescent tags custom-tailored to specific applications.
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