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Zhang A, Guo Z, Ge G, Liu Z. Insights into In Vivo Environmental Effects on Quantitative Biochemistry in Single Cells. Anal Chem 2023; 95:17246-17255. [PMID: 37963214 DOI: 10.1021/acs.analchem.3c03102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Biomacromolecules exist and function in a crowded and spatially confined intracellular milieu. Single-cell analysis has been an essential tool for deciphering the molecular mechanisms of cell biology and cellular heterogeneity. However, a sound understanding of in vivo environmental effects on single-cell quantification has not been well established. In this study, via cell mimicking with giant unilamellar vesicles and single-cell analysis by an approach called plasmonic immunosandwich assay (PISA) that we developed previously, we investigated the effects of two in vivo environmental factors, i.e., molecular crowding and spatial confinement, on quantitative biochemistry in the cytoplasm of single cells. We find that molecular crowding greatly affects the biomolecular interactions and immunorecognition-based detection while the effect of spatial confinement in cell-sized space is negligible. Without considering the effect of molecular crowding, the results by PISA were found to be apparently under-quantitated, being only 29.5-50.0% of those by the calibration curve considering the effect of molecular crowding. We further demonstrated that the use of a calibration curve established with standard solutions containing 20% (wt) polyethylene glycol 6000 can well offset the effect of intracellular crowding and thereby provide a simple but accurate calibration for the PISA measurement. Thus, this study not only sheds light on how intracellular environmental factors influence biomolecular interactions and immunorecognition-based single-cell quantification but also provides a simple but effective strategy to make the single-cell analysis more accurate.
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Affiliation(s)
- Anqi Zhang
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Zhanchen Guo
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Ge Ge
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
| | - Zhen Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China
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2
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Ye H, Wang M, Yu X, Ma P, Zhu P, Zhong J, He K, Guo Y. Molecular Docking Insight into the Label-Free Fluorescence Aptasensor for Ochratoxin A Detection. Molecules 2023; 28:4841. [PMID: 37375396 DOI: 10.3390/molecules28124841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/07/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Ochratoxin A (OTA) is the most common mycotoxin and can be found in wheat, corn and other grain products. As OTA pollution in these grain products is gaining prominence as a global issue, the demand to develop OTA detection technology has attracted increasing attention. Recently, a variety of label-free fluorescence biosensors based on aptamer have been established. However, the binding mechanisms of some aptasensors are still unclear. Herein, a label-free fluorescent aptasensor employing Thioflavin T (ThT) as donor for OTA detection was constructed based on the G-quadruplex aptamer of the OTA aptamer itself. The key binding region of aptamer was revealed by using molecular docking technology. In the absence of the OTA target, ThT fluorescent dye binds with the OTA aptamer to form an aptamer/ThT complex, and results in the fluorescence intensity being obviously enhanced. In the presence of OTA, the OTA aptamer binds to OTA because of its high affinity and specificity to form an aptamer/OTA complex, and the ThT fluorescent dye is released from the OTA aptamer into the solution. Therefore, the fluorescence intensity is significantly decreased. Molecular docking results revealed that OTA is binding to the pocket-like structure and surrounded by the A29-T3 base pair and C4, T30, G6 and G7 of the aptamer. Meanwhile, this aptasensor shows good selectivity, sensitivity and an excellent recovery rate of the wheat flour spiked experiment.
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Affiliation(s)
- Hua Ye
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Mengyuan Wang
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Xi Yu
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Pengfei Ma
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Ping Zhu
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Jianjun Zhong
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
| | - Kuo He
- College of Agriculture and Forestry Science and Technology, Hebei North University, Zhangjiakou 075000, China
| | - Yuanxin Guo
- School of Grain Science and Technology, Jiangsu University of Science and Technology, Zhenjiang 212100, China
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3
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Endoh T, Tan JH, Chen SB, Sugimoto N. Cladogenetic Orthogonal Light-Up Aptamers for Simultaneous Detection of Multiple Small Molecules in Cells. Anal Chem 2023; 95:976-985. [PMID: 36541622 DOI: 10.1021/acs.analchem.2c03598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent successes in construction of light-up RNA aptamers allowed fluorescence-based live-cell imaging of RNAs. In addition, light-up aptamers have been converted into signaling aptamers that enable fluorometric detection of small chemicals. To date, only a single target chemical has been detected at a time in cells. In this study, we selected cladogenetic orthogonal light-up aptamers that output three different colors from the RNA library having the same ligand binding core. Two of the three functioned in mammalian cells. These two aptamers, which fluoresce blue and green upon binding of cognate fluorogen, were converted into signaling aptamers. Using these signaling aptamers in combination with a previously described light-up aptamer with red fluorescence, we demonstrated simultaneous detection of multiple chemicals in living cells. The cladogenetic orthogonal light-up aptamers developed in this study and the simple strategy for rational designing of the signaling aptamers will provide innovative advances in the field of RNA-based bioimaging.
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Affiliation(s)
- Tamaki Endoh
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Kobe650-0047, Japan
| | - Jia-Heng Tan
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou510006, China
| | - Shuo-Bin Chen
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou510006, China
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-minamimachi, Kobe650-0047, Japan.,Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-minamimachi, Kobe650-0047, Japan
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4
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Alternative RNA Conformations: Companion or Combatant. Genes (Basel) 2022; 13:genes13111930. [DOI: 10.3390/genes13111930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 11/04/2022] Open
Abstract
RNA molecules, in one form or another, are involved in almost all aspects of cell physiology, as well as in disease development. The diversity of the functional roles of RNA comes from its intrinsic ability to adopt complex secondary and tertiary structures, rivaling the diversity of proteins. The RNA molecules form dynamic ensembles of many interconverting conformations at a timescale of seconds, which is a key for understanding how they execute their cellular functions. Given the crucial role of RNAs in various cellular processes, we need to understand the RNA molecules from a structural perspective. Central to this review are studies aimed at revealing the regulatory role of conformational equilibria in RNA in humans to understand genetic diseases such as cancer and neurodegenerative diseases, as well as in pathogens such as bacteria and viruses so as to understand the progression of infectious diseases. Furthermore, we also summarize the prior studies on the use of RNA structures as platforms for the rational design of small molecules for therapeutic applications.
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5
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Li X, Bhullar AS, Binzel DW, Guo P. The dynamic, motile and deformative properties of RNA nanoparticles facilitate the third milestone of drug development. Adv Drug Deliv Rev 2022; 186:114316. [PMID: 35526663 DOI: 10.1016/j.addr.2022.114316] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/25/2022] [Accepted: 04/29/2022] [Indexed: 12/13/2022]
Abstract
Besides mRNA, rRNA, and tRNA, cells contain many other noncoding RNA that display critical roles in the regulation of cellular functions. Human genome sequencing revealed that the majority of non-protein-coding DNA actually codes for non-coding RNAs. The dynamic nature of RNA results in its motile and deformative behavior. These conformational transitions such as the change of base-pairing, breathing within complemented strands, and pseudoknot formation at the 2D level as well as the induced-fit and conformational capture at the 3D level are important for their biological functions including regulation, translation, and catalysis. The dynamic, motile and catalytic activity has led to a belief that RNA is the origin of life. We have recently reported that the deformative property of RNA nanoparticles enhances their penetration through the leaky blood vessel of cancers which leads to highly efficient tumor accumulation. This special deformative property also enables RNA nanoparticles to pass the glomerulus, overcoming the filtration size limit, resulting in fast renal excretion and rapid body clearance, thus low or no toxicity. The biodistribution of RNA nanoparticles can be further improved by the incorporation of ligands for cancer targeting. In addition to the favorable biodistribution profiles, RNA nanoparticles possess other properties including self-assembly, negative charge, programmability, and multivalency; making it a great material for pharmaceutical applications. The intrinsic negative charge of RNA nanoparticles decreases the toxicity of drugs by preventing nonspecific binding to the negative charged cell membrane and enhancing the solubility of hydrophobic drugs. The polyvalent property of RNA nanoparticles allows the multi-functionalization which can apply to overcome drug resistance. This review focuses on the summary of these unique properties of RNA nanoparticles, which describes the mechanism of RNA dynamic, motile and deformative properties, and elucidates and prepares to welcome the RNA therapeutics as the third milestone in pharmaceutical drug development.
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Affiliation(s)
- Xin Li
- College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States
| | - Abhjeet S Bhullar
- Interdisciplinary Biophysics Graduate Program, College of Art and Science, The Ohio State University, Columbus, OH 43210, United States
| | - Daniel W Binzel
- College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States.
| | - Peixuan Guo
- College of Pharmacy, The Ohio State University, Columbus, OH 43210, United States; Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210, United States; James Comprehensive Cancer Center, The Ohio State University, Columbus, OH 43210, United States; College of Medicine, The Ohio State University, Columbus, OH 43210, United States.
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6
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Zhang J, Huang Y, Sun M, Wan S, Yang C, Song Y. Recent Advances in Aptamer-Based Liquid Biopsy. ACS APPLIED BIO MATERIALS 2022; 5:1954-1979. [PMID: 35014838 DOI: 10.1021/acsabm.1c01202] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Liquid biopsy capable of noninvasive and real-time molecular profiling is considered as a breakthrough technology, endowing an opportunity for precise diagnosis of individual patients. Extracellular vesicles (EVs) and circulating tumor cells (CTCs) consisting of substantial disease-related molecular information play an important role in liquid biopsy. Therefore, it is critically significant to exploit high-performance recognition ligands for efficient isolation and analysis of EVs and CTCs from complex body fluids. Aptamers exhibit extraordinary merits of high specificity and affinity, which are considered as superior recognition ligands for liquid biopsy. In this review, we first summarize recent advanced strategies for the evolution of high-performance aptamers and the construction of various aptamer-based recognition elements. Subsequently, we mainly discuss the isolation and analysis of EVs and CTCs based on the aptamer functioned biomaterials/biointerface. Ultimately, we envision major challenges and future direction of aptamer-based liquid biopsy for clinical utilities.
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Affiliation(s)
- Jialu Zhang
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yihao Huang
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Miao Sun
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Shuang Wan
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chaoyong Yang
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.,Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Yanling Song
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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7
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Chen Q, Li Y, Lin C, Chen L, Luo H, Xia S, Liu C, Cheng X, Liu C, Li J, Dou D. OUP accepted manuscript. Nucleic Acids Res 2022; 50:e67. [PMID: 35288754 PMCID: PMC9262588 DOI: 10.1093/nar/gkac173] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 02/02/2022] [Accepted: 03/04/2022] [Indexed: 11/21/2022] Open
Abstract
DNA-encoded library (DEL) technology is a powerful tool for small molecule identification in drug discovery, yet the reported DEL selection strategies were applied primarily on protein targets in either purified form or in cellular context. To expand the application of this technology, we employed DEL selection on an RNA target HIV-1 TAR (trans-acting responsive region), but found that the majority of signals were resulted from false positive DNA–RNA binding. We thus developed an optimized selection strategy utilizing RNA patches and competitive elution to minimize unwanted DNA binding, followed by k-mer analysis and motif search to differentiate false positive signal. This optimized strategy resulted in a very clean background in a DEL selection against Escherichia coli FMN Riboswitch, and the enriched compounds were determined with double digit nanomolar binding affinity, as well as similar potency in functional FMN competition assay. These results demonstrated the feasibility of small molecule identification against RNA targets using DEL selection. The developed experimental and computational strategy provided a promising opportunity for RNA ligand screening and expanded the application of DEL selection to a much wider context in drug discovery.
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Affiliation(s)
| | | | | | - Liu Chen
- HitGen Inc., Shuangliu District, Chengdu, China
| | - Hao Luo
- HitGen Inc., Shuangliu District, Chengdu, China
| | - Shuai Xia
- HitGen Inc., Shuangliu District, Chengdu, China
| | - Chuan Liu
- HitGen Inc., Shuangliu District, Chengdu, China
| | | | | | - Jin Li
- HitGen Inc., Shuangliu District, Chengdu, China
| | - Dengfeng Dou
- To whom correspondence should be addressed. Tel: +86 28 85197385 8700;
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8
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A transient conformation facilitates ligand binding to the adenine riboswitch. iScience 2021; 24:103512. [PMID: 34927032 PMCID: PMC8652005 DOI: 10.1016/j.isci.2021.103512] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/14/2021] [Accepted: 11/22/2021] [Indexed: 11/29/2022] Open
Abstract
RNAs adopt various conformations to perform different functions in cells. Incapable of acquiring intermediates, the key initiations of ligand recognition in the adenine riboswitch have not been characterized. In this work, stopped-flow fluorescence was used to track structural switches in the full-length adenine riboswitch in real time. We used PLOR (position-selective labeling of RNA) to incorporate fluorophores into desired positions in the RNA. The switching sequence P1 responded to adenine more rapidly than helix P4 and the binding pocket, followed by stabilization of the binding pocket, P4, and annealing of P1. Moreover, a transient intermediate consisting of an unwound P1 was detected during adenine binding. These events were observed in both the WT riboswitch and a functional mutant. The findings provide insight into the conformational changes of the riboswitch RNA triggered by a ligand. Real-time tracking of the adenine riboswitch at nucleotide resolution A transient conformation with unwound P1 is identified in the adenine riboswitch Helix P1 responds to ligand quicker than the binding pocket or expression platform
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9
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Sugimoto N, Endoh T, Takahashi S, Tateishi-Karimata H. Chemical Biology of Double Helical and Non-Double Helical Nucleic Acids: “To B or Not To B, That Is the Question”. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20210131] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 17-1-20 Minatojima-minamimachi, Kobe, Hyogo 650-0047, Japan
- Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 17-1-20 Minatojima-minamimachi, Kobe, Hyogo 650-0047, Japan
| | - Tamaki Endoh
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 17-1-20 Minatojima-minamimachi, Kobe, Hyogo 650-0047, Japan
| | - Shuntaro Takahashi
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 17-1-20 Minatojima-minamimachi, Kobe, Hyogo 650-0047, Japan
| | - Hisae Tateishi-Karimata
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 17-1-20 Minatojima-minamimachi, Kobe, Hyogo 650-0047, Japan
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10
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Nakatsuka N, Abendroth JM, Yang KA, Andrews AM. Divalent Cation Dependence Enhances Dopamine Aptamer Biosensing. ACS APPLIED MATERIALS & INTERFACES 2021; 13:9425-9435. [PMID: 33410656 PMCID: PMC7933093 DOI: 10.1021/acsami.0c17535] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Oligonucleotide receptors (aptamers), which change conformation upon target recognition, enable electronic biosensing under high ionic-strength conditions when coupled to field-effect transistors (FETs). Because highly negatively charged aptamer backbones are influenced by ion content and concentration, biosensor performance and target sensitivities were evaluated under application conditions. For a recently identified dopamine aptamer, physiological concentrations of Mg2+ and Ca2+ in artificial cerebrospinal fluid produced marked potentiation of dopamine FET-sensor responses. By comparison, divalent cation-associated signal amplification was not observed for FET sensors functionalized with a recently identified serotonin aptamer or a previously reported dopamine aptamer. Circular dichroism spectroscopy revealed Mg2+- and Ca2+-induced changes in target-associated secondary structure for the new dopamine aptamer, but not the serotonin aptamer nor the old dopamine aptamer. Thioflavin T displacement corroborated the Mg2+ dependence of the new dopamine aptamer for target detection. These findings imply allosteric binding interactions between divalent cations and dopamine for the new dopamine aptamer. Developing and testing sensors in ionic environments that reflect intended applications are best practices for identifying aptamer candidates with favorable attributes and elucidating sensing mechanisms.
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Affiliation(s)
- Nako Nakatsuka
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - John M. Abendroth
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Kyung-Ae Yang
- Division of Experimental Therapeutics, Department of Medicine, Columbia University, New York, New York 10032, United States
| | - Anne M. Andrews
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, United States
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, United States
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, CA 90095, United States
- Corresponding Author:
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11
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Scull CE, Dandpat SS, Romero RA, Walter NG. Transcriptional Riboswitches Integrate Timescales for Bacterial Gene Expression Control. Front Mol Biosci 2021; 7:607158. [PMID: 33521053 PMCID: PMC7838592 DOI: 10.3389/fmolb.2020.607158] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/11/2020] [Indexed: 12/16/2022] Open
Abstract
Transcriptional riboswitches involve RNA aptamers that are typically found in the 5' untranslated regions (UTRs) of bacterial mRNAs and form alternative secondary structures upon binding to cognate ligands. Alteration of the riboswitch's secondary structure results in perturbations of an adjacent expression platform that controls transcription elongation and termination, thus turning downstream gene expression "on" or "off." Riboswitch ligands are typically small metabolites, divalent cations, anions, signaling molecules, or other RNAs, and can be part of larger signaling cascades. The interconnectedness of ligand binding, RNA folding, RNA transcription, and gene expression empowers riboswitches to integrate cellular processes and environmental conditions across multiple timescales. For a successful response to an environmental cue that may determine a bacterium's chance of survival, a coordinated coupling of timescales from microseconds to minutes must be achieved. This review focuses on recent advances in our understanding of how riboswitches affect such critical gene expression control across time.
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Affiliation(s)
| | | | | | - Nils G. Walter
- Department of Chemistry, Single Molecule Analysis Group and Center for RNA Biomedicine, University of Michigan, Ann Arbor, MI, United States
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12
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Di Cera E. Mechanisms of ligand binding. BIOPHYSICS REVIEWS 2020; 1:011303. [PMID: 33313600 PMCID: PMC7714259 DOI: 10.1063/5.0020997] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/09/2020] [Indexed: 12/25/2022]
Abstract
Many processes in chemistry and biology involve interactions of a ligand with its molecular target. Interest in the mechanism governing such interactions has dominated theoretical and experimental analysis for over a century. The interpretation of molecular recognition has evolved from a simple rigid body association of the ligand with its target to appreciation of the key role played by conformational transitions. Two conceptually distinct descriptions have had a profound impact on our understanding of mechanisms of ligand binding. The first description, referred to as induced fit, assumes that conformational changes follow the initial binding step to optimize the complex between the ligand and its target. The second description, referred to as conformational selection, assumes that the free target exists in multiple conformations in equilibrium and that the ligand selects the optimal one for binding. Both descriptions can be merged into more complex reaction schemes that better describe the functional repertoire of macromolecular systems. This review deals with basic mechanisms of ligand binding, with special emphasis on induced fit, conformational selection, and their mathematical foundations to provide rigorous context for the analysis and interpretation of experimental data. We show that conformational selection is a surprisingly versatile mechanism that includes induced fit as a mathematical special case and even captures kinetic properties of more complex reaction schemes. These features make conformational selection a dominant mechanism of molecular recognition in biology, consistent with the rich conformational landscape accessible to biological macromolecules being unraveled by structural biology.
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Affiliation(s)
- Enrico Di Cera
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA
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13
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Ganser LR, Kelly ML, Herschlag D, Al-Hashimi HM. The roles of structural dynamics in the cellular functions of RNAs. Nat Rev Mol Cell Biol 2020; 20:474-489. [PMID: 31182864 DOI: 10.1038/s41580-019-0136-0] [Citation(s) in RCA: 263] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RNAs fold into 3D structures that range from simple helical elements to complex tertiary structures and quaternary ribonucleoprotein assemblies. The functions of many regulatory RNAs depend on how their 3D structure changes in response to a diverse array of cellular conditions. In this Review, we examine how the structural characterization of RNA as dynamic ensembles of conformations, which form with different probabilities and at different timescales, is improving our understanding of RNA function in cells. We discuss the mechanisms of gene regulation by microRNAs, riboswitches, ribozymes, post-transcriptional RNA modifications and RNA-binding proteins, and how the cellular environment and processes such as liquid-liquid phase separation may affect RNA folding and activity. The emerging RNA-ensemble-function paradigm is changing our perspective and understanding of RNA regulation, from in vitro to in vivo and from descriptive to predictive.
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Affiliation(s)
- Laura R Ganser
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Megan L Kelly
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford ChEM-H Chemistry, Engineering, and Medicine for Human Health, Stanford University, Stanford, CA, USA.,Department of Chemical Engineering, Stanford ChEM-H Chemistry, Engineering, and Medicine for Human Health, Stanford University, Stanford, CA, USA.,Department of Chemistry, Stanford ChEM-H Chemistry, Engineering, and Medicine for Human Health, Stanford University, Stanford, CA, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA. .,Department of Chemistry, Duke University, Durham, NC, USA.
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Endoh T, Ohyama T, Sugimoto N. RNA-Capturing Microsphere Particles (R-CAMPs) for Optimization of Functional Aptamers. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1805062. [PMID: 30773785 DOI: 10.1002/smll.201805062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 01/23/2019] [Indexed: 06/09/2023]
Abstract
RNA aptamers are useful building blocks for constructing functional nucleic acid-based nanoarchitectures. The abilities of aptamers to recognize specific ligands have also been utilized for various biotechnological applications. Solution conditions, which can differ depending on the application, impact the affinity of the aptamers, and thus it is important to optimize the aptamers for the solution conditions to be employed. To simplify the aptamer optimization process, an efficient method that enables re-selection of an aptamer from a partially randomized library is developed. The process relies on RNA-capturing microsphere particles (R-CAMPs): each particle displays different clones of identical DNA and RNA sequences. Using a fluorescence-activated cell sorter, the R-CAMPs that are linked to functional aptamers are sorted. It is demonstrated that after a single round of reselection, several functional aptamers, including the wild-type, are selected from a library of 16 384 sequences. The selection using R-CAMPs is further performed under the solution containing high concentration of ethylene glycol, suggesting applicability in various conditions to optimize an aptamer for a particular application. As any type of RNA clone can be displayed on the microspheres, the technology demonstrated here will be useful for the selection of RNAs based on diverse functions.
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Affiliation(s)
- Tamaki Endoh
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
| | - Tatsuya Ohyama
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
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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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16
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Hata Y, Sawada T, Serizawa T. Macromolecular crowding for materials-directed controlled self-assembly. J Mater Chem B 2018; 6:6344-6359. [PMID: 32254643 DOI: 10.1039/c8tb02201a] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Macromolecular crowding refers to intracellular environments where various macromolecules, including proteins and nucleic acids, are present at high total concentrations. Its influence on biological processes has been investigated using a highly concentrated in vitro solution of water-soluble polymers as a model. Studies have revealed significant effects of macromolecular crowding on the thermodynamic equilibria and dynamics of biomolecular self-assembly in vivo. Recently, macromolecular crowding has attracted materials scientists, especially those in bio-related areas, as a tool to control molecular/colloidal self-assembly. Macromolecular crowding has been exploited to control the structure of supramolecular materials, assemble nanomaterials, and improve the performance of polymeric materials. Furthermore, nanostructured materials have been shown to be an interesting alternative to water-soluble polymers for creating crowded environments for controlled self-assembly. In this review article, we summarize recent progress in research on macromolecular crowding for controlled self-assembly in bio-related materials chemistry.
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Affiliation(s)
- Yuuki Hata
- Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 2-12-1-H121 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
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