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Wills MF, Alejo CB, Hundt N, Hudson AJ, Eperon IC. FluoroTensor: Identification and tracking of colocalised molecules and their stoichiometries in multi-colour single molecule imaging via deep learning. Comput Struct Biotechnol J 2024; 23:918-928. [PMID: 38375530 PMCID: PMC10875188 DOI: 10.1016/j.csbj.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 02/21/2024] Open
Abstract
The identification of photobleaching steps in single molecule fluorescence imaging is a well-established procedure for analysing the stoichiometries of molecular complexes. Nonetheless, the method is challenging with protein fluorophores because of the high levels of noise, rapid bleaching and highly variable signal intensities, all of which complicate methods based on statistical analyses of intensities to identify bleaching steps. It has recently been shown that deep learning by convolutional neural networks can yield an accurate analysis with a relatively short computational time. We describe here an improved use of such an approach that detects bleaching events even in the first time point of observation, and we have included this within an integrated software package incorporating fluorescence spot detection, colocalisation, tracking, FRET and photobleaching step analyses of single molecules or complexes. This package, known as FluoroTensor, is written in Python with a self-explanatory user interface.
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Affiliation(s)
- Max F.K. Wills
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Molecular and Cell Biology, University of Leicester, UK
| | - Carlos Bueno Alejo
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Chemistry, University of Leicester, UK
| | - Nikolas Hundt
- Department of Cellular Physiology, Ludwig-Maximilians-Universität München, Germany
| | - Andrew J. Hudson
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Chemistry, University of Leicester, UK
| | - Ian C. Eperon
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Molecular and Cell Biology, University of Leicester, UK
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2
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Ma X, Zhang Y, Huang K, Zhu L, Xu W. Multifunctional rolling circle transcription-based nanomaterials for advanced drug delivery. Biomaterials 2023; 301:122241. [PMID: 37451000 DOI: 10.1016/j.biomaterials.2023.122241] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/21/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
As the up-and-comer in the development of RNA nanotechnology, RNA nanomaterials based on functionalized rolling circle transcription (RCT) have become promising carriers for drug production and delivery. This is due to RCT technology can self-produce polyvalent tandem nucleic acid prodrugs for intervention in intracellular gene expression and protein production. RNA component strands participating in de novo assembly enable RCT-based nanomaterials to exhibit good mechanical properties, biostability, and biocompatibility as delivery carriers. The biostability makes it to suitable for thermodynamically/kinetically favorable assembly, enzyme resistance and efficient expression in vivo. Controllable RCT system combined with polymers enables customizable and adjustable size, shape, structure, and stoichiometry of RNA building materials, which provide groundwork for the delivery of advanced drugs. Here, we review the assembly strategies and the dynamic regulation of RCT-based nanomaterials, summarize its functional properties referring to the bottom-up design philosophy, and describe its advancements in tumor gene therapy, synergistic chemotherapy, and immunotherapy. Last, we elaborate on the unique and practical value of RCT-based nanomaterials, namely "self-production and self-sale", and their potential challenges in nanotechnology, material science and biomedicine.
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Affiliation(s)
- Xuan Ma
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Yangzi Zhang
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Kunlun Huang
- College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China
| | - Longjiao Zhu
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China
| | - Wentao Xu
- Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083, China; College of Food Science and Nutrition Engineering, China Agricultural University, Beijing, 100083, China.
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3
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Torres A, Cockerell S, Phillips M, Balázsi G, Ghosh K. MaxCal can infer models from coupled stochastic trajectories of gene expression and cell division. Biophys J 2023; 122:2623-2635. [PMID: 37218129 PMCID: PMC10397576 DOI: 10.1016/j.bpj.2023.05.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 05/03/2023] [Accepted: 05/18/2023] [Indexed: 05/24/2023] Open
Abstract
Gene expression is inherently noisy due to small numbers of proteins and nucleic acids inside a cell. Likewise, cell division is stochastic, particularly when tracking at the level of a single cell. The two can be coupled when gene expression affects the rate of cell division. Single-cell time-lapse experiments can measure both fluctuations by simultaneously recording protein levels inside a cell and its stochastic division. These information-rich noisy trajectory data sets can be harnessed to learn about the underlying molecular and cellular details that are often not known a priori. A critical question is: How can we infer a model given data where fluctuations at two levels-gene expression and cell division-are intricately convoluted? We show the principle of maximum caliber (MaxCal)-integrated within a Bayesian framework-can be used to infer several cellular and molecular details (division rates, protein production, and degradation rates) from these coupled stochastic trajectories (CSTs). We demonstrate this proof of concept using synthetic data generated from a known model. An additional challenge in data analysis is that trajectories are often not in protein numbers, but in noisy fluorescence that depends on protein number in a probabilistic manner. We again show that MaxCal can infer important molecular and cellular rates even when data are in fluorescence, another example of CST with three confounding factors-gene expression noise, cell division noise, and fluorescence distortion-all coupled. Our approach will provide guidance to build models in synthetic biology experiments as well as general biological systems where examples of CSTs are abundant.
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Affiliation(s)
- Andrew Torres
- Department of Physics and Astronomy, University of Denver, Denver, Colorado
| | - Spencer Cockerell
- Department of Physics and Astronomy, University of Denver, Denver, Colorado
| | - Michael Phillips
- Department of Physics and Astronomy, University of Denver, Denver, Colorado
| | - Gábor Balázsi
- Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York
| | - Kingshuk Ghosh
- Molecular and Cellular Biophysics, University of Denver, Denver, Colorado; Department of Physics and Astronomy, University of Denver, Denver, Colorado.
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4
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Bohmer M, Bhullar AS, Weitao T, Zhang L, Lee JH, Guo P. Revolving hexameric ATPases as asymmetric motors to translocate double-stranded DNA genome along one strand. iScience 2023; 26:106922. [PMID: 37305704 PMCID: PMC10250835 DOI: 10.1016/j.isci.2023.106922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023] Open
Abstract
DsDNA translocation through nanoscale pores is generally accomplished by ATPase biomotors. The discovery of the revolving dsDNA translocation mechanism, as opposed to rotation, in bacteriophage phi29 elucidated how ATPase motors move dsDNA. Revolution-driven, hexameric dsDNA motors have been reported in herpesvirus, bacterial FtsK, Streptomyces TraB, and T7 phage. This review explores the common relationship between their structure and mechanisms. Commonalities include moving along the 5'→3' strand, inchworm sequential action leading to an asymmetrical structure, channel chirality, channel size, and 3-step channel gating for controlling motion direction. The revolving mechanism and contact with one of the dsDNA strands addresses the historic controversy of dsDNA packaging using nicked, gapped, hybrid, or chemically modified DNA. These controversies surrounding dsDNA packaging activity using modified materials can be answered by whether the modification was introduced into the 3'→5' or 5'→3' strand. Perspectives concerning solutions to the controversy of motor structure and stoichiometry are also discussed.
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Affiliation(s)
- Margaret Bohmer
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Abhjeet S. Bhullar
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
- Interdisciplinary Biophysics Graduate Program, College of Art and Science, The Ohio State University, Columbus, OH 43210, USA
| | - Tao Weitao
- Center for the Genetics of Host Defense UT Southwestern Medical Center, Dallas, TX, USA
| | - Long Zhang
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Jing-Huei Lee
- Department of Biomedical Engineering, College of Engineering and Applied Science, University of Cincinnati, Cincinnati, OH, USA
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
- College of Pharmacy, Division of Pharmaceutics and Pharmacology, The Ohio State University, Columbus, OH, USA
- College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
- Interdisciplinary Biophysics Graduate Program, College of Art and Science, The Ohio State University, Columbus, OH 43210, USA
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5
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Saurabh A, Niekamp S, Sgouralis I, Pressé S. Modeling Non-additive Effects in Neighboring Chemically Identical Fluorophores. J Phys Chem B 2022; 126:10.1021/acs.jpcb.2c01889. [PMID: 35649158 PMCID: PMC9712593 DOI: 10.1021/acs.jpcb.2c01889] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantitative fluorescence analysis is often used to derive chemical properties, including stoichiometries, of biomolecular complexes. One fundamental underlying assumption in the analysis of fluorescence data─whether it be the determination of protein complex stoichiometry by super-resolution, or step-counting by photobleaching, or the determination of RNA counts in diffraction-limited spots in RNA fluorescence in situ hybridization (RNA-FISH) experiments─is that fluorophores behave identically and do not interact. However, recent experiments on fluorophore-labeled DNA origami structures such as fluorocubes have shed light on the nature of the interactions between identical fluorophores as these are brought closer together, thereby raising questions on the validity of the modeling assumption that fluorophores do not interact. Here, we analyze photon arrival data under pulsed illumination from fluorocubes where distances between dyes range from 2 to 10 nm. We discuss the implications of non-additivity of brightness on quantitative fluorescence analysis.
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Affiliation(s)
- Ayush Saurabh
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona 85287, United States
| | - Stefan Niekamp
- Massachusetts General Hospital, Boston, Massachusetts 02114, United States
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158, United States
| | - Ioannis Sgouralis
- Department of Mathematics, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Steve Pressé
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona 85287, United States
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
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6
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A viral genome packaging ring-ATPase is a flexibly coordinated pentamer. Nat Commun 2021; 12:6548. [PMID: 34772936 PMCID: PMC8589836 DOI: 10.1038/s41467-021-26800-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/21/2021] [Indexed: 01/13/2023] Open
Abstract
Multi-subunit ring-ATPases carry out a myriad of biological functions, including genome packaging in viruses. Though the basic structures and functions of these motors have been well-established, the mechanisms of ATPase firing and motor coordination are poorly understood. Here, using single-molecule fluorescence, we determine that the active bacteriophage T4 DNA packaging motor consists of five subunits of gp17. By systematically doping motors with an ATPase-defective subunit and selecting single motors containing a precise number of active or inactive subunits, we find that the packaging motor can tolerate an inactive subunit. However, motors containing one or more inactive subunits exhibit fewer DNA engagements, a higher failure rate in encapsidation, reduced packaging velocity, and increased pausing. These findings suggest a DNA packaging model in which the motor, by re-adjusting its grip on DNA, can skip an inactive subunit and resume DNA translocation, suggesting that strict coordination amongst motor subunits of packaging motors is not crucial for function.
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Binzel DW, Li X, Burns N, Khan E, Lee WJ, Chen LC, Ellipilli S, Miles W, Ho YS, Guo P. Thermostability, Tunability, and Tenacity of RNA as Rubbery Anionic Polymeric Materials in Nanotechnology and Nanomedicine-Specific Cancer Targeting with Undetectable Toxicity. Chem Rev 2021; 121:7398-7467. [PMID: 34038115 PMCID: PMC8312718 DOI: 10.1021/acs.chemrev.1c00009] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
RNA nanotechnology is the bottom-up self-assembly of nanometer-scale architectures, resembling LEGOs, composed mainly of RNA. The ideal building material should be (1) versatile and controllable in shape and stoichiometry, (2) spontaneously self-assemble, and (3) thermodynamically, chemically, and enzymatically stable with a long shelf life. RNA building blocks exhibit each of the above. RNA is a polynucleic acid, making it a polymer, and its negative-charge prevents nonspecific binding to negatively charged cell membranes. The thermostability makes it suitable for logic gates, resistive memory, sensor set-ups, and NEM devices. RNA can be designed and manipulated with a level of simplicity of DNA while displaying versatile structure and enzyme activity of proteins. RNA can fold into single-stranded loops or bulges to serve as mounting dovetails for intermolecular or domain interactions without external linking dowels. RNA nanoparticles display rubber- and amoeba-like properties and are stretchable and shrinkable through multiple repeats, leading to enhanced tumor targeting and fast renal excretion to reduce toxicities. It was predicted in 2014 that RNA would be the third milestone in pharmaceutical drug development. The recent approval of several RNA drugs and COVID-19 mRNA vaccines by FDA suggests that this milestone is being realized. Here, we review the unique properties of RNA nanotechnology, summarize its recent advancements, describe its distinct attributes inside or outside the body and discuss potential applications in nanotechnology, medicine, and material science.
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Affiliation(s)
- Daniel W Binzel
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Xin Li
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Nicolas Burns
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Eshan Khan
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, College of Medicine, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wen-Jui Lee
- TMU Research Center of Cancer Translational Medicine, School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan
| | - Li-Ching Chen
- TMU Research Center of Cancer Translational Medicine, School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan
| | - Satheesh Ellipilli
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
| | - Wayne Miles
- Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, College of Medicine, Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yuan Soon Ho
- TMU Research Center of Cancer Translational Medicine, School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Department of Laboratory Medicine, Taipei Medical University Hospital, Taipei 110, Taiwan
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, College of Pharmacy, Dorothy M. Davis Heart and Lung Research Institute, James Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, Ohio 43210, United States
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8
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Tibbs J, Ghoneim M, Caldwell CC, Buzynski T, Bowie W, Boehm EM, Washington MT, Tabei SMA, Spies M. KERA: analysis tool for multi-process, multi-state single-molecule data. Nucleic Acids Res 2021; 49:e53. [PMID: 33660771 PMCID: PMC8136784 DOI: 10.1093/nar/gkab087] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/17/2021] [Accepted: 02/24/2021] [Indexed: 12/16/2022] Open
Abstract
Molecular machines within cells dynamically assemble, disassemble and reorganize. Molecular interactions between their components can be observed at the single-molecule level and quantified using colocalization single-molecule spectroscopy, in which individual labeled molecules are seen transiently associating with a surface-tethered partner, or other total internal reflection fluorescence microscopy approaches in which the interactions elicit changes in fluorescence in the labeled surface-tethered partner. When multiple interacting partners can form ternary, quaternary and higher order complexes, the types of spatial and temporal organization of these complexes can be deduced from the order of appearance and reorganization of the components. Time evolution of complex architectures can be followed by changes in the fluorescence behavior in multiple channels. Here, we describe the kinetic event resolving algorithm (KERA), a software tool for organizing and sorting the discretized fluorescent trajectories from a range of single-molecule experiments. KERA organizes the data in groups by transition patterns, and displays exhaustive dwell time data for each interaction sequence. Enumerating and quantifying sequences of molecular interactions provides important information regarding the underlying mechanism of the assembly, dynamics and architecture of the macromolecular complexes. We demonstrate KERA's utility by analyzing conformational dynamics of two DNA binding proteins: replication protein A and xeroderma pigmentosum complementation group D helicase.
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Affiliation(s)
- Joseph Tibbs
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Mohamed Ghoneim
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Colleen C Caldwell
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Troy Buzynski
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Wayne Bowie
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Elizabeth M Boehm
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - M Todd Washington
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - S M Ali Tabei
- Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614, USA
| | - Maria Spies
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
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9
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de Sousa Machado JN, Vollmar L, Schimpf J, Chaudhury P, Kumariya R, van der Does C, Hugel T, Albers SV. Autophosphorylation of the KaiC-like protein ArlH inhibits oligomerization and interaction with ArlI, the motor ATPase of the archaellum. Mol Microbiol 2021; 116:943-956. [PMID: 34219289 DOI: 10.1111/mmi.14781] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/02/2021] [Accepted: 07/02/2021] [Indexed: 12/27/2022]
Abstract
Motile archaea are propelled by the archaellum, whose motor complex consists of the membrane protein ArlJ, the ATPase ArlI, and the ATP-binding protein ArlH. Despite its essential function and the existence of structural and biochemical data on ArlH, the role of ArlH in archaellum assembly and function remains elusive. ArlH is a structural homolog of KaiC, the central component of the cyanobacterial circadian clock. Since autophosphorylation and dephosphorylation of KaiC are central properties for the function of KaiC, we asked whether autophosphorylation is also a property of ArlH proteins. We observed that both ArlH from the euryarchaeon Pyrococcus furiosus (PfArlH) and from the crenarchaeon Sulfolobus acidocaldarius (SaArlH) have autophosphorylation activity. Using a combination of single-molecule fluorescence measurements and biochemical assays, we show that autophosphorylation of ArlH is closely linked to its oligomeric state when bound to hexameric ArlI. These experiments also strongly suggest that ArlH is a hexamer in its ArlI-bound state. Mutagenesis of the putative catalytic residue (Glu-57 in SaArlH) in ArlH results in a reduced autophosphorylation activity and abolished archaellation and motility in S. acidocaldarius, indicating that optimum phosphorylation activity of ArlH is essential for archaellation and motility.
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Affiliation(s)
- J Nuno de Sousa Machado
- Molecular Biology of Archaea and Signaling Research Centre BIOSS, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Leonie Vollmar
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany.,Institute of Physical Chemistry and Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Julia Schimpf
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany.,Institute of Physical Chemistry and Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Paushali Chaudhury
- Molecular Biology of Archaea and Signaling Research Centre BIOSS, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Rashmi Kumariya
- Molecular Biology of Archaea and Signaling Research Centre BIOSS, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Chris van der Does
- Molecular Biology of Archaea and Signaling Research Centre BIOSS, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Thorsten Hugel
- Institute of Physical Chemistry and Signaling Research Centers BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea and Signaling Research Centre BIOSS, Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, Germany
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10
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Das A, Vishvakarma V, Dey A, Dey S, Gupta A, Das M, Vishwakarma KK, Roy DS, Yadav S, Kesarwani S, Venkatramani R, Maiti S. Biophysical properties of the isolated spike protein binding helix of human ACE2. Biophys J 2021; 120:2785-2792. [PMID: 34214538 PMCID: PMC8241576 DOI: 10.1016/j.bpj.2021.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/22/2021] [Accepted: 06/17/2021] [Indexed: 12/13/2022] Open
Abstract
The entry of the severe acute respiratory syndrome coronavirus 2 virus in human cells is mediated by the binding of its surface spike protein to the human angiotensin-converting enzyme 2 (ACE2) receptor. A 23-residue long helical segment (SBP1) at the binding interface of human ACE2 interacts with viral spike protein and therefore has generated considerable interest as a recognition element for virus detection. Unfortunately, emerging reports indicate that the affinity of SBP1 to the receptor-binding domain of the spike protein is much lower than that of the ACE2 receptor itself. Here, we examine the biophysical properties of SBP1 to reveal factors leading to its low affinity for the spike protein. Whereas SBP1 shows good solubility (solubility > 0.8 mM), circular dichroism spectroscopy shows that it is mostly disordered with some antiparallel β-sheet content and no helicity. The helicity is substantial (>20%) only upon adding high concentrations (≥20% v/v) of 2,2,2-trifluoroethanol, a helix promoter. Fluorescence correlation spectroscopy and single-molecule photobleaching studies show that the peptide oligomerizes at concentrations >50 nM. We hypothesized that mutating the hydrophobic residues (F28, F32, and F40) of SBP1, which do not directly interact with the spike protein, to alanine would reduce peptide oligomerization without affecting its spike binding affinity. Whereas the mutant peptide (SBP1mod) shows substantially reduced oligomerization propensity, it does not show improved helicity. Our study shows that the failure of efforts, so far, to produce a short SBP1 mimic with a high affinity for the spike protein is not only due to the lack of helicity but is also due to the heretofore unrecognized problem of oligomerization.
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Affiliation(s)
- Anirban Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Vicky Vishvakarma
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Arpan Dey
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Simli Dey
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Ankur Gupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Mitradip Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | | | - Debsankar Saha Roy
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Swati Yadav
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Shubham Kesarwani
- Centre for Cardiovascular Biology and Disease, Institute of Stem Cell Science and Regenerative Medicine (inStem), Gandhi Krishi Vigyan Kendra Campus, Bangalore, Karnataka, India
| | - Ravindra Venkatramani
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Colaba, Mumbai, India.
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11
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Lee TY, Li YC, Lin MG, Hsiao CD, Li HW. Single-molecule binding characterization of primosomal protein PriA involved in replication restart. Phys Chem Chem Phys 2021; 23:13745-13751. [PMID: 34159970 DOI: 10.1039/d1cp00638j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
DNA damage leads to stalled or collapsed replication forks. Replication restart primosomes re-initiate DNA synthesis at these stalled or collapsed DNA replication forks, which is important for bacterial survival. Primosomal protein PriA specifically recognizes the DNA fork structure and recruits other primosomal proteins to load the replicative helicase, in order to re-establish the replication fork. PriA binding on DNA is the first step to restart replication forks for proper DNA repair. Using a single-molecule fluorescence colocalization experiment, we measured the thermodynamic and real-time kinetic properties of fluorescence-labeled Gram-positive bacteria Geobacillus stearothermophilus PriA binding on DNA forks. We showed that PriA preferentially binds to a DNA fork structure with a fully duplexed leading strand at sub-nanomolar affinity (Kd = 268 ± 99 pM). PriA binds dynamically, and its association and dissociation rate constants can be determined using the appearance and disappearance of the fluorescence signal. In addition, we showed that PriA binds to DNA forks as a monomer using photobleaching step counting. This information offers a molecular basis essential for understanding the mechanism of replication restart.
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Affiliation(s)
- Tzu-Yu Lee
- Department of Chemistry, National Taiwan University, Taiwan.
| | - Yi-Ching Li
- Institute of Molecular Biology, Academia Sinica, Taiwan.
| | - Min-Guan Lin
- Institute of Molecular Biology, Academia Sinica, Taiwan.
| | | | - Hung-Wen Li
- Department of Chemistry, National Taiwan University, Taiwan.
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12
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Saeed AFUH, Chan C, Guan H, Gong B, Guo P, Cheng X, Ouyang S. Structural Insights into gp16 ATPase in the Bacteriophage ϕ29 DNA Packaging Motor. Biochemistry 2021; 60:886-897. [PMID: 33689296 DOI: 10.1021/acs.biochem.0c00935] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Biological motors, ubiquitous in living systems, convert chemical energy into different kinds of mechanical motions critical to cellular functions. Gene product 16 (gp16) in bacteriophage ϕ29 is among the most powerful biomotors known, which adopts a multisubunit ring-shaped structure and hydrolyzes ATP to package double-stranded DNA (dsDNA) into a preformed procapsid. Here we report the crystal structure of the C-terminal domain of gp16 (gp16-CTD). Structure-based alignment and molecular dynamics simulations revealed an essential binding surface of gp16-CTD for prohead RNA, a unique component of the motor complex. Furthermore, our simulations highlighted a dynamic interplay between the N-terminal domain and the CTD of gp16, which may play a role in driving movement of DNA into the procapsid. Lastly, we assembled an atomic structural model of the complete ϕ29 dsDNA packaging motor complex by integrating structural and experimental data from multiple sources. Collectively, our findings provided a refined inchworm-revolution model for dsDNA translocation in bacteriophage ϕ29 and suggested how the individual domains of gp16 work together to power such translocation.
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Affiliation(s)
- Abdullah F U H Saeed
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
- College of Chemistry and Materials Science, Fujian Normal University, Fuzhou 350117, China
| | - Chun Chan
- College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
| | - Hongxin Guan
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
| | - Bing Gong
- Guangxi Key Laboratory of Marine Disaster in the Beibu Gulf, Beibu Gulf University, Qinzhou 535000, China
| | - Peixuan Guo
- College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
- Center for RNA Nanobiotechnology and Nanomedicine, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute, and Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, United States
| | - Xiaolin Cheng
- College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, United States
- Biophysics Graduate Program and Translational Data Analytics Institute, The Ohio State University, Columbus, Ohio 43210, United States
| | - Songying Ouyang
- The Key Laboratory of Innate Immune Biology of Fujian Province, Provincial University Key Laboratory of Cellular Stress Response and Metabolic Regulation, Biomedical Research Center of South China, Key Laboratory of OptoElectronic Science and Technology for Medicine of Ministry of Education, College of Life Sciences, Fujian Normal University, Fuzhou 350117, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266237, China
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13
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de Sousa Machado JN, Vollmar L, Schimpf J, Chaudhury P, Kumariya R, van der Does C, Hugel T, Albers S. Autophosphorylation of the KaiC-like protein ArlH inhibits oligomerisation and interaction with ArlI, the motor ATPase of the archaellum.. [DOI: 10.1101/2021.03.19.436134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
Motile archaea are propelled by the archaellum, whose motor complex consists of the membrane protein ArlJ, the ATPase ArlI, and the ATP-binding protein ArlH. Despite its essential function and the existence of structural and biochemical data on ArlH, the role of ArlH in archaellum assembly and function remains elusive. ArlH is a structural homolog of KaiC, the central component of the cyanobacterial circadian clock. Similar to KaiC, ArlH exhibits autophosphorylation activity, which was observed for both ArlH of the euryarchaeonPyrococcus furiosus (PfArlH)and the crenarchaeonSulfolobus acidocaldarius(SaArlH). Using a combination of single molecule fluorescence measurements and biochemical assays, it is shown that autophosphorylation of ArlH is closely linked to the oligomeric state of ArlH bound to ArlI. These experiments also strongly suggest that ArlH is a hexamer in its functional ArlI bound state. Mutagenesis of the putative catalytic residue Glu-57 inSaArlH results in a reduced autophosphorylation activity and abolished archaellation and motility, suggesting that optimum phosphorylation activity of ArlH is essential for both archaellation and motility.
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14
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Translation of the long-term fundamental studies on viral DNA packaging motors into nanotechnology and nanomedicine. SCIENCE CHINA-LIFE SCIENCES 2020; 63:1103-1129. [DOI: 10.1007/s11427-020-1752-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/04/2020] [Indexed: 02/07/2023]
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15
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Dey S, Das A, Maiti S. Correction of Systematic Bias in Single Molecule Photobleaching Measurements. Biophys J 2020; 118:1101-1108. [PMID: 31972157 DOI: 10.1016/j.bpj.2019.12.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/02/2019] [Accepted: 12/30/2019] [Indexed: 10/25/2022] Open
Abstract
Single molecule photobleaching is a powerful technique to measure the number of fluorescent units in subresolution molecular complexes, such as in toxic protein oligomers associated with amyloid diseases. However, photobleaching can occur before the sample is appropriately placed and focused. Such "prebleaching" can introduce a strong systematic bias toward smaller oligomers. Quantitative correction of prebleaching is known to be an ill-posed problem, limiting the utility of the technique. Here, we provide an experimental solution to improve its reliability. We chemically construct multimeric standards to estimate the prebleaching probability, B. We show that B can be used as a constraint to reliably correct the statistics obtained from a known distribution of standard oligomers. Finally, we apply this method to the data obtained from a heterogeneous oligomeric solution of human islet amyloid polypeptide. Our results show that photobleaching can critically skew the estimation of oligomeric distributions, so that low abundance monomers display a much higher apparent abundance. In summary, any inference from photobleaching experiments with B > 0.1 is likely to be unreliable, but our method can be used to quantitatively correct possible errors.
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Affiliation(s)
- Simli Dey
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Anirban Das
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Sudipta Maiti
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India.
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16
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Xu J, Wang D, Gui M, Xiang Y. Structural assembly of the tailed bacteriophage ϕ29. Nat Commun 2019; 10:2366. [PMID: 31147544 PMCID: PMC6542822 DOI: 10.1038/s41467-019-10272-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 04/24/2019] [Indexed: 11/30/2022] Open
Abstract
The mature virion of the tailed bacteriophage ϕ29 is an ~33 MDa complex that contains more than 450 subunits of seven structural proteins assembling into a prolate head and a short non-contractile tail. Here, we report the near-atomic structures of the ϕ29 pre-genome packaging head (prohead), the mature virion and the genome-emptied virion. Structural comparisons suggest local rotation or oscillation of the head-tail connector upon DNA packaging and release. Termination of the DNA packaging occurs through pressure-dependent correlative positional and conformational changes in the connector. The funnel-shaped tail lower collar attaches the expanded narrow end of the connector and has a 180-Å long, 24-strand β barrel narrow stem tube that undergoes conformational changes upon genome release. The appendages form an interlocked assembly attaching the tail around the collar. The membrane active long loops at the distal end of the tail knob exit during the late stage of infection and form the cone-shaped tip of a largely hydrophobic helix barrel, prepared for membrane penetration. Mature particles of bacteriophage ϕ29 consist of a 33-MDa complex formed by over 450 subunits, assembled into a head and a short tail. Here, Xu et al. report the near-atomic structures of the ϕ29 prohead, the mature virion and the genome-emptied virion, providing insights into DNA packaging and release.
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Affiliation(s)
- Jingwei Xu
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.,Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule Zürich, CH-8093, Zürich, Switzerland
| | - Dianhong Wang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China
| | - Miao Gui
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Ye Xiang
- Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Center for Infectious Disease Research, Department of Basic Medical Sciences, School of Medicine, Tsinghua University, 100084, Beijing, China.
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17
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Xu J, Qin G, Luo F, Wang L, Zhao R, Li N, Yuan J, Fang X. Automated Stoichiometry Analysis of Single-Molecule Fluorescence Imaging Traces via Deep Learning. J Am Chem Soc 2019; 141:6976-6985. [DOI: 10.1021/jacs.9b00688] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Jiachao Xu
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Gege Qin
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fang Luo
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lina Wang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rong Zhao
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nan Li
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinghe Yuan
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaohong Fang
- Key Laboratory of Molecular Nanostructure and Nanotechnology, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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18
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Firman T, Amgalan A, Ghosh K. Maximum Caliber Can Build and Infer Models of Oscillation in a Three-Gene Feedback Network. J Phys Chem B 2019; 123:343-355. [PMID: 30507199 DOI: 10.1021/acs.jpcb.8b07465] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Single-cell protein expression time trajectories provide rich temporal data quantifying cellular variability and its role in dictating fitness. However, theoretical models to analyze and fully extract information from these measurements remain limited for three reasons: (i) gene expression profiles are noisy, rendering models of averages inapplicable, (ii) experiments typically measure only a few protein species while leaving other molecular actors-necessary to build traditional bottom-up models-unnoticed, and (iii) measured data are in fluorescence, not particle number. We recently addressed these challenges in an alternate top-down approach using the principle of Maximum Caliber (MaxCal) to model genetic switches with one and two protein species. In the present work we address scalability and broader applicability of MaxCal by extending to a three-gene (A, B, C) feedback network that exhibits oscillation, commonly known as the repressilator. We test MaxCal's inferential power by using synthetic data of noisy protein number time traces-serving as a proxy for experimental data-generated from a known underlying model. We notice that the minimal MaxCal model-accounting for production, degradation, and only one type of symmetric coupling between all three species-reasonably infers several underlying features of the circuit such as the effective production rate, degradation rate, frequency of oscillation, and protein number distribution. Next, we build models of higher complexity including different levels of coupling between A, B, and C and rigorously assess their relative performance. While the minimal model (with four parameters) performs remarkably well, we note that the most complex model (with six parameters) allowing all possible forms of crosstalk between A, B, and C slightly improves prediction of rates, but avoids ad hoc assumption of all the other models. It is also the model of choice based on Bayesian information criteria. We further analyzed time trajectories in arbitrary fluorescence (using synthetic trajectories) to mimic realistic data. We conclude that even with a three-protein system including both fluorescence noise and intrinsic gene expression fluctuations, MaxCal can faithfully infer underlying details of the network, opening future directions to model other network motifs with many species.
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19
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Firman T, Amgalan A, Ghosh K. Maximum Caliber Can Build and Infer Models of Oscillation in a Three-Gene Feedback Network. J Phys Chem A 2018. [DOI: 10.1021/acs.jpca.8b07465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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20
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Xu Y, Pang L, Wang H, Xu C, Shah H, Guo P, Shu D, Qian SY. Specific delivery of delta-5-desaturase siRNA via RNA nanoparticles supplemented with dihomo-γ-linolenic acid for colon cancer suppression. Redox Biol 2018; 21:101085. [PMID: 30584980 PMCID: PMC6305700 DOI: 10.1016/j.redox.2018.101085] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/11/2018] [Accepted: 12/17/2018] [Indexed: 02/07/2023] Open
Abstract
We have previously demonstrated that DGLA treatment along with Delta-5-Desaturase (D5D) siRNA in various types of cancer cells enhances the formation of 8-HOA from COX-2-catalyzed DGLA peroxidation, which in turn inhibits cancer cell growth and migration. However, delivery of naked siRNA remains a formidable challenge due to its "off-target" effect. In this study, we employed RNA nanotechnology for specific delivery of D5D-siRNA to xenograft colon tumors using 3WJ RNA nanoparticles. When a targeting module, i.e., the EpCAM aptamer, was incorporated, the 3WJ pRNA nanoparticles were able specifically deliver D5D siRNA to human colon cancer HCA-7 cells both in vitro and in vivo, resulting in significant downregulation of D5D expression. Co-treatment with DGLA in combination with 3WJ-EpCAM-siRNA induced a higher DGLA/AA ratio and enhanced formation of 8-HOA at a threshold level, and in HCA-7 tumor-bearing mice, induced significant tumor suppression. We further confirmed that 8-HOA formation, promoted by COX-2-catalyzed DGLA peroxidation, inhibited HDAC and consequently induced apoptosis in tumor cells. Therefore, the 3WJ RNA nanoparticle system holds great promise as a suitable therapeutic delivery platform for colon cancer therapy.
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Affiliation(s)
- Yi Xu
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Lizhi Pang
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Hongzhi Wang
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH, USA; College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Congcong Xu
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH, USA; College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Harshit Shah
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH, USA; College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Dan Shu
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA; College of Pharmacy, Division of Pharmaceutics and Pharmaceutical Chemistry, The Ohio State University, Columbus, OH, USA; College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Steven Y Qian
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND, USA.
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21
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Høiberg HC, Sparvath SM, Andersen VL, Kjems J, Andersen ES. An RNA Origami Octahedron with Intrinsic siRNAs for Potent Gene Knockdown. Biotechnol J 2018; 14:e1700634. [PMID: 29802763 DOI: 10.1002/biot.201700634] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 05/17/2018] [Indexed: 12/13/2022]
Abstract
The fields of DNA and RNA nanotechnology have established nucleic acids as valuable building blocks for functional nanodevices with applications in nanomedicine. Here, a simple method for designing and assembling a 3D scaffolded RNA origami wireframe structure with intrinsic functioning small interfering RNAs (siRNAs) embedded is introduced. Uniquely, the method uses an mRNA fragment as scaffold strand, which is folded by sequence-complementarity of nine shorter synthetic strands. High-yield production of the intended 3D structure is verified by transmission electron microscopy (TEM). Production of functional siRNAs is facilitated by incorporating recognition sites for Dicer at selected locations in the structure, and efficient silencing of a target reporter gene is demonstrated.
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Affiliation(s)
| | - Steffen M Sparvath
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus 8000 C, Denmark
| | - Veronica L Andersen
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus 8000 C, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
| | - Jørgen Kjems
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus 8000 C, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
| | - Ebbe S Andersen
- Interdisciplinary Nanoscience Center, Aarhus University, Aarhus 8000 C, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus 8000 C, Denmark
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22
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Shu Y, Yin H, Rajabi M, Li H, Vieweger M, Guo S, Shu D, Guo P. RNA-based micelles: A novel platform for paclitaxel loading and delivery. J Control Release 2018; 276:17-29. [PMID: 29454064 PMCID: PMC5964609 DOI: 10.1016/j.jconrel.2018.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 02/08/2018] [Accepted: 02/09/2018] [Indexed: 12/22/2022]
Abstract
RNA can serve as powerful building blocks for bottom-up fabrication of nanostructures for biotechnological and biomedical applications. In addition to current self-assembly strategies utilizing base pairing, motif piling and tertiary interactions, we reported for the first time the formation of RNA based micellar nanoconstruct with a cholesterol molecule conjugated onto one helical end of a branched pRNA three-way junction (3WJ) motif. The resulting amphiphilic RNA micelles consist of a hydrophilic RNA head and a covalently linked hydrophobic lipid tail that can spontaneously assemble in aqueous solution via hydrophobic interaction. Taking advantage of pRNA 3WJ branched structure, the assembled RNA micelles are capable of escorting multiple functional modules. As a proof of concept for delivery for therapeutics, Paclitaxel was loaded into the RNA micelles with significantly improved water solubility. The successful construction of the drug loaded RNA micelles was confirmed and characterized by agarose gel electrophoresis, atomic force microscopy (AFM), dynamic light scattering (DLS), and fluorescence Nile Red encapsulation assay. The estimate critical micelle formation concentration ranges from 39 nM to 78 nM. The Paclitaxel loaded RNA micelles can internalize into cancer cells and inhibit their proliferation. Further studies showed that the Paclitaxel loaded RNA micelles induced cancer cell apoptosis in a Caspase-3 dependent manner but RNA micelles alone exhibited low cytotoxicity. Finally, the Paclitaxel loaded RNA micelles targeted to tumor in vivo without accumulation in healthy tissues and organs. There is also no or very low induction of pro-inflammatory response. Therefore, multivalence, cancer cell permeability, combined with controllable assembly, low or non toxic nature, and tumor targeting are all promising features that make our pRNA micelles a suitable platform for potential drug delivery.
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Affiliation(s)
- Yi Shu
- Nanobiotechnology Center, Markey Cancer Center and Department of Pharmaceutical Sciences/College of Pharmacy, University of Kentucky, Lexington, KY 40536, United States
| | - Hongran Yin
- Center for RNA Nanobiotechnology and Nanomedicine, Division of Pharmaceutics and Pharmaceutical Chemistry/College of Pharmacy, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State Universtiy, Columbus, OH 43210, United States
| | - Mehdi Rajabi
- Nanobiotechnology Center, Markey Cancer Center and Department of Pharmaceutical Sciences/College of Pharmacy, University of Kentucky, Lexington, KY 40536, United States
| | - Hui Li
- Center for RNA Nanobiotechnology and Nanomedicine, Division of Pharmaceutics and Pharmaceutical Chemistry/College of Pharmacy, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State Universtiy, Columbus, OH 43210, United States; Nanobiotechnology Center, Markey Cancer Center and Department of Pharmaceutical Sciences/College of Pharmacy, University of Kentucky, Lexington, KY 40536, United States
| | - Mario Vieweger
- Center for RNA Nanobiotechnology and Nanomedicine, Division of Pharmaceutics and Pharmaceutical Chemistry/College of Pharmacy, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State Universtiy, Columbus, OH 43210, United States
| | - Sijin Guo
- Center for RNA Nanobiotechnology and Nanomedicine, Division of Pharmaceutics and Pharmaceutical Chemistry/College of Pharmacy, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State Universtiy, Columbus, OH 43210, United States
| | - Dan Shu
- Center for RNA Nanobiotechnology and Nanomedicine, Division of Pharmaceutics and Pharmaceutical Chemistry/College of Pharmacy, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State Universtiy, Columbus, OH 43210, United States
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, Division of Pharmaceutics and Pharmaceutical Chemistry/College of Pharmacy, College of Medicine, Dorothy M. Davis Heart and Lung Research Institute and James Comprehensive Cancer Center, The Ohio State Universtiy, Columbus, OH 43210, United States.
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23
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Ray S, Widom JR, Walter NG. Life under the Microscope: Single-Molecule Fluorescence Highlights the RNA World. Chem Rev 2018; 118:4120-4155. [PMID: 29363314 PMCID: PMC5918467 DOI: 10.1021/acs.chemrev.7b00519] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The emergence of single-molecule (SM) fluorescence techniques has opened up a vast new toolbox for exploring the molecular basis of life. The ability to monitor individual biomolecules in real time enables complex, dynamic folding pathways to be interrogated without the averaging effect of ensemble measurements. In parallel, modern biology has been revolutionized by our emerging understanding of the many functions of RNA. In this comprehensive review, we survey SM fluorescence approaches and discuss how the application of these tools to RNA and RNA-containing macromolecular complexes in vitro has yielded significant insights into the underlying biology. Topics covered include the three-dimensional folding landscapes of a plethora of isolated RNA molecules, their assembly and interactions in RNA-protein complexes, and the relation of these properties to their biological functions. In all of these examples, the use of SM fluorescence methods has revealed critical information beyond the reach of ensemble averages.
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Affiliation(s)
| | | | - Nils G. Walter
- Department of Chemistry, Single Molecule Analysis Group, University of Michigan, Ann Arbor, MI 48109, USA
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24
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Shi X, He Y, Gao W, Liu X, Ye Z, Liu H, Xiao L. Quantifying the Degree of Aggregation from Fluorescent Dye-Conjugated DNA Probe by Single Molecule Photobleaching Technology for the Ultrasensitive Detection of Adenosine. Anal Chem 2018; 90:3661-3665. [PMID: 29468866 DOI: 10.1021/acs.analchem.7b05317] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In this work, we demonstrated a single molecule photobleaching-based strategy for the ultrasensitive detection of adenosine. A modified split aptamer was designed to specifically recognize individual adenosine molecules in solution. The specific binding of dye-labeled short strand DNA probes onto the elongated aptamer strand in the presence of adenosine resulted in a concentration-dependent self-aggregation process. The degree-of-aggregation (DOA) of the short DNA probes on the elongated aptamer strand could then be accurately determined based on the single molecule photobleaching measurement. Through statistically analyzing the DOA under different target concentrations, a well-defined curvilinear relationship between the DOA and target molecule concentration (e.g., adenosine) was established. The limit-of-detection (LOD) is down to 44.5 pM, which is lower than those recently reported results with fluorescence-based analysis. Owing to the high sensitivity and excellent selectivity, the sensing strategy described herein would find broad applications in biomolecule analysis under complicated surroundings.
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Affiliation(s)
- Xingbo Shi
- Hunan Provincial Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology , Hunan Agricultural University , Changsha , 410128 , China.,State Key Laboratory of Chemo/Biosensing and Chemometrics , Hunan University , Changsha 410082 , China
| | - Yu He
- Hunan Provincial Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology , Hunan Agricultural University , Changsha , 410128 , China
| | - Wenli Gao
- Hunan Provincial Key Laboratory of Food Science and Biotechnology, College of Food Science and Technology , Hunan Agricultural University , Changsha , 410128 , China
| | - Xiaoying Liu
- College of Science , Hunan Agricultural University , Changsha , 410128 , China
| | - Zhongju Ye
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin , 300071 , China
| | - Hua Liu
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin , 300071 , China
| | - Lehui Xiao
- State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry , Nankai University , Tianjin , 300071 , China
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25
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Firman T, Wedekind S, McMorrow TJ, Ghosh K. Maximum Caliber Can Characterize Genetic Switches with Multiple Hidden Species. J Phys Chem B 2018; 122:5666-5677. [PMID: 29406749 DOI: 10.1021/acs.jpcb.7b12251] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Gene networks with feedback often involve interactions between multiple species of biomolecules, much more than experiments can actually monitor. Coupled with this is the challenge that experiments often measure gene expression in noisy fluorescence instead of protein numbers. How do we infer biophysical information and characterize the underlying circuits from this limited and convoluted data? We address this by building stochastic models using the principle of Maximum Caliber (MaxCal). MaxCal uses the basic information on synthesis, degradation, and feedback-without invoking any other auxiliary species and ad hoc reactions-to generate stochastic trajectories similar to those typically measured in experiments. MaxCal in conjunction with Maximum Likelihood (ML) can infer parameters of the model using fluctuating trajectories of protein expression over time. We demonstrate the success of the MaxCal + ML methodology using synthetic data generated from known circuits of different genetic switches: (i) a single-gene autoactivating circuit involving five species (including mRNA), (ii) a mutually repressing two-gene circuit (toggle switch) with seven species (including mRNA) considering stochastic time traces of two proteins, and (iii) the same toggle switch circuit considering stochastic time traces of only one of the two proteins. To further challenge the MaxCal + ML inference scheme, we repeat our analysis for the second and third scenario with traces expressed in noisy fluorescence instead of protein number to closely mimic typical experiments. We show that, for all of these models with increasing complexity and obfuscation, the minimal model of MaxCal is still able to capture the fluctuations of the trajectory and infer basic underlying rate parameters when benchmarked against the known values used to generate the synthetic data. Importantly, the model also yields an effective feedback parameter that can be used to quantify interactions within these circuits. These applications show the promise of MaxCal's ability to characterize circuits with limited data, and its utility to better understand evolution and advance design strategies for specific functions.
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Affiliation(s)
- Taylor Firman
- Molecular and Cellular Biophysics , University of Denver , Denver , Colorado 80209 , United States
| | - Stephen Wedekind
- Department of Physics and Astronomy , University of Denver , Denver , Colorado 80209 , United States
| | - T J McMorrow
- Department of Physics and Astronomy , University of Denver , Denver , Colorado 80209 , United States
| | - Kingshuk Ghosh
- Department of Physics and Astronomy , University of Denver , Denver , Colorado 80209 , United States
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26
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Haque F, Zhang H, Wang S, Chang CL, Savran C, Guo P. Methods for Single-Molecule Sensing and Detection Using Bacteriophage Phi29 DNA Packaging Motor. Methods Mol Biol 2018; 1805:423-450. [PMID: 29971730 DOI: 10.1007/978-1-4939-8556-2_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Bacteriophage phi29 DNA packaging motor consists of a dodecameric portal channel protein complex termed connector that allows transportation of genomic dsDNA and a hexameric packaging RNA (pRNA) ring to gear the motor. The elegant design of the portal protein has facilitated its applications for real-time single-molecule detection of biopolymers and chemicals with high sensitivity and selectivity. The robust self-assembly property of the pRNA has enabled biophysical studies of the motor complex to determine the stoichiometry and structure/folding of the pRNA at single-molecule level. This chapter focuses on biophysical and analytical methods for studying the phi29 motor components at the single-molecule level, such as single channel conductance assays of membrane-embedded connectors; single molecule photobleaching (SMPB) assay for determining the stoichiometry of phi29 motor components; fluorescence resonance energy transfer (FRET) assay for determining the structure and folding of pRNA; atomic force microscopy (AFM) for imaging pRNA nanoparticles of various size, shape, and stoichiometry; and bright-field microscopy with magnetomechanical system for direct visualization of viral DNA packaging process. The phi29 system with explicit engineering capability has incredible potentials for diverse applications in nanotechnology and nanomedicine including, but not limited to, DNA sequencing, drug delivery to diseased cells, environmental surveillance, and early disease diagnosis.
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Affiliation(s)
- Farzin Haque
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, Dorothy M Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.,Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Hui Zhang
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, Dorothy M Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.,Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Shaoying Wang
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH, USA.,Department of Physiology and Cell Biology, Dorothy M Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA.,Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA
| | - Chun-Li Chang
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.,School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Cagri Savran
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA.,School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA.,Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Peixuan Guo
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, The Ohio State University, Columbus, OH, USA. .,Department of Physiology and Cell Biology, Dorothy M Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA. .,Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA. .,Markey Cancer Center, University of Kentucky, Lexington, KY, USA. .,Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, USA. .,Sylvan G. Frank Endowed Chair in Pharmaceutics and Drug Delivery, The Ohio State University, Columbus, OH, USA.
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27
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Firman T, Balázsi G, Ghosh K. Building Predictive Models of Genetic Circuits Using the Principle of Maximum Caliber. Biophys J 2017; 113:2121-2130. [PMID: 29117534 DOI: 10.1016/j.bpj.2017.08.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/25/2017] [Accepted: 08/31/2017] [Indexed: 11/17/2022] Open
Abstract
Learning the underlying details of a gene network is a major challenge in cellular and synthetic biology. We address this challenge by building a chemical kinetic model that utilizes information encoded in the stochastic protein expression trajectories typically measured in experiments. The applicability of the proposed method is demonstrated in an auto-activating genetic circuit, a common motif in natural and synthetic gene networks. Our approach is based on the principle of maximum caliber (MaxCal)-a dynamical analog of the principle of maximum entropy-and builds a minimal model using only three constraints: 1) protein synthesis, 2) protein degradation, and 3) positive feedback. The MaxCal-generated model (described with four parameters) was benchmarked against synthetic data generated using a Gillespie algorithm on a known reaction network (with seven parameters). MaxCal accurately predicts underlying rate parameters of protein synthesis and degradation as well as experimental observables such as protein number and dwell-time distributions. Furthermore, MaxCal yields an effective feedback parameter that can be useful for circuit design. We also extend our methodology and demonstrate how to analyze trajectories that are not in protein numbers but in arbitrary fluorescence units, a more typical condition in experiments. This "top-down" methodology based on minimal information-in contrast to traditional "bottom-up" approaches that require ad hoc knowledge of circuit details-provides a powerful tool to accurately infer underlying details of feedback circuits that are not otherwise visible in experiments and to help guide circuit design.
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Affiliation(s)
- Taylor Firman
- Department of Physics and Astronomy, Molecular and Cellular Biophysics, University of Denver, Denver, Colorado
| | - Gábor Balázsi
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York; Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York
| | - Kingshuk Ghosh
- Department of Physics and Astronomy, Molecular and Cellular Biophysics, University of Denver, Denver, Colorado.
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28
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Zhao Z, Zhang H, Shu D, Montemagno C, Ding B, Li J, Guo P. Construction of Asymmetrical Hexameric Biomimetic Motors with Continuous Single-Directional Motion by Sequential Coordination. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:10.1002/smll.201601600. [PMID: 27709780 PMCID: PMC5217803 DOI: 10.1002/smll.201601600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 08/12/2016] [Indexed: 05/21/2023]
Abstract
The significance of bionanomotors in nanotechnology is analogous to mechanical motors in daily life. Here the principle and approach for designing and constructing biomimetic nanomotors with continuous single-directional motion are reported. This bionanomotor is composed of a dodecameric protein channel, a six-pRNA ring, and an ATPase hexamer. Based on recent elucidations of the one-way revolving mechanisms of the phi29 double-stranded DNA (dsDNA) motor, various RNA and protein elements are designed and tested by single-molecule imaging and biochemical assays, with which the motor with active components has been constructed. The motor motion direction is controlled by three operation elements: (1) Asymmetrical ATPase with ATP-interacting domains for alternative DNA binding/pushing regulated by an arginine finger in a sequential action manner. The arginine finger bridges two adjacent ATPase subunits into a non-covalent dimer, resulting in an asymmetrical hexameric complex containing one dimer and four monomers. (2) The dsDNA translocation channel as a one-way valve. (3) The hexameric pRNA ring geared with left-/right-handed loops. Assessments of these constructs reveal that one inactive subunit of pRNA/ATPase is sufficient to completely block motor function (defined as K = 1), implying that these components work sequentially based on the principle of binomial distribution and Yang Hui's triangle.
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Affiliation(s)
- Zhengyi Zhao
- College of Pharmacy; College of Medicine/Department of Physiology & Cell Biology/Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Hui Zhang
- College of Pharmacy; College of Medicine/Department of Physiology & Cell Biology/Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Dan Shu
- College of Pharmacy; College of Medicine/Department of Physiology & Cell Biology/Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
| | - Carlo Montemagno
- Chemical and Materials Engineering and Ingenuity Lab, University of Alberta, Edmonton, Alberta, Canada
| | - Baoquan Ding
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Jingyuan Li
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China and Institute of High Energy Physics, Beijing, China
| | - Peixuan Guo
- College of Pharmacy; College of Medicine/Department of Physiology & Cell Biology/Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, USA
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29
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Tsekouras K, Custer TC, Jashnsaz H, Walter NG, Pressé S. A novel method to accurately locate and count large numbers of steps by photobleaching. Mol Biol Cell 2016; 27:3601-3615. [PMID: 27654946 PMCID: PMC5221592 DOI: 10.1091/mbc.e16-06-0404] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 09/15/2016] [Indexed: 12/19/2022] Open
Abstract
Photobleaching event counting is a single-molecule fluorescence technique that is increasingly being used to determine the stoichiometry of protein and RNA complexes composed of many subunits in vivo as well as in vitro. By tagging protein or RNA subunits with fluorophores, activating them, and subsequently observing as the fluorophores photobleach, one obtains information on the number of subunits in a complex. The noise properties in a photobleaching time trace depend on the number of active fluorescent subunits. Thus, as fluorophores stochastically photobleach, noise properties of the time trace change stochastically, and these varying noise properties have created a challenge in identifying photobleaching steps in a time trace. Although photobleaching steps are often detected by eye, this method only works for high individual fluorophore emission signal-to-noise ratios and small numbers of fluorophores. With filtering methods or currently available algorithms, it is possible to reliably identify photobleaching steps for up to 20-30 fluorophores and signal-to-noise ratios down to ∼1. Here we present a new Bayesian method of counting steps in photobleaching time traces that takes into account stochastic noise variation in addition to complications such as overlapping photobleaching events that may arise from fluorophore interactions, as well as on-off blinking. Our method is capable of detecting ≥50 photobleaching steps even for signal-to-noise ratios as low as 0.1, can find up to ≥500 steps for more favorable noise profiles, and is computationally inexpensive.
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Affiliation(s)
- Konstantinos Tsekouras
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202
| | - Thomas C Custer
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI 48109.,Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Hossein Jashnsaz
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Steve Pressé
- Department of Physics, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202 .,Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN 46202
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30
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Liesche C, Grussmayer KS, Ludwig M, Wörz S, Rohr K, Herten DP, Beaudouin J, Eils R. Automated Analysis of Single-Molecule Photobleaching Data by Statistical Modeling of Spot Populations. Biophys J 2016; 109:2352-62. [PMID: 26636946 DOI: 10.1016/j.bpj.2015.10.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/01/2015] [Accepted: 10/26/2015] [Indexed: 02/01/2023] Open
Abstract
The number of fluorophores within a molecule complex can be revealed by single-molecule photobleaching imaging. A widely applied strategy to analyze intensity traces over time is the quantification of photobleaching step counts. However, several factors can limit and bias the detection of photobleaching steps, including noise, high numbers of fluorophores, and the possibility that several photobleaching events occur almost simultaneously. In this study, we propose a new approach, to our knowledge, to determine the fluorophore number that correlates the intensity decay of a population of molecule complexes with the decay of the number of visible complexes. We validated our approach using single and fourfold Atto-labeled DNA strands. As an example we estimated the subunit stoichiometry of soluble CD95L using GFP fusion proteins. To assess the precision of our method we performed in silico experiments showing that the estimates are not biased for experimentally observed intensity fluctuations and that the relative precision remains constant with increasing number of fluorophores. In case of fractional fluorescent labeling, our simulations predicted that the fluorophore number estimate corresponds to the product of the true fluorophore number with the labeling fraction. Our method, denoted by spot number and intensity correlation (SONIC), is fully automated, robust to noise, and does not require the counting of photobleaching events.
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Affiliation(s)
- Clarissa Liesche
- Division of Theoretical Bioinformatics (B080), German Cancer Research Center (DKFZ), Heidelberg, Germany; Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Kristin S Grussmayer
- CellNetworks Cluster and Institute for Physical Chemistry, BioQuant, Heidelberg University, Heidelberg, Germany
| | - Michael Ludwig
- CellNetworks Cluster and Institute for Physical Chemistry, BioQuant, Heidelberg University, Heidelberg, Germany
| | - Stefan Wörz
- Division of Theoretical Bioinformatics (B080), German Cancer Research Center (DKFZ), Heidelberg, Germany; Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Karl Rohr
- Division of Theoretical Bioinformatics (B080), German Cancer Research Center (DKFZ), Heidelberg, Germany; Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Dirk-Peter Herten
- CellNetworks Cluster and Institute for Physical Chemistry, BioQuant, Heidelberg University, Heidelberg, Germany
| | - Joël Beaudouin
- Division of Theoretical Bioinformatics (B080), German Cancer Research Center (DKFZ), Heidelberg, Germany; Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany
| | - Roland Eils
- Division of Theoretical Bioinformatics (B080), German Cancer Research Center (DKFZ), Heidelberg, Germany; Department for Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University, Heidelberg, Germany.
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31
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Pi F, Zhao Z, Chelikani V, Yoder K, Kvaratskhelia M, Guo P. Development of Potent Antiviral Drugs Inspired by Viral Hexameric DNA-Packaging Motors with Revolving Mechanism. J Virol 2016; 90:8036-46. [PMID: 27356896 PMCID: PMC5008075 DOI: 10.1128/jvi.00508-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasitic nature of viruses and the emergence of antiviral drug resistance necessitate the development of new potent antiviral drugs. Recently, a method for developing potent inhibitory drugs by targeting biological machines with high stoichiometry and a sequential-action mechanism was described. Inspired by this finding, we reviewed the development of antiviral drugs targeting viral DNA-packaging motors. Inhibiting multisubunit targets with sequential actions resembles breaking one bulb in a series of Christmas lights, which turns off the entire string. Indeed, studies on viral DNA packaging might lead to the development of new antiviral drugs. Recent elucidation of the mechanism of the viral double-stranded DNA (dsDNA)-packaging motor with sequential one-way revolving motion will promote the development of potent antiviral drugs with high specificity and efficiency. Traditionally, biomotors have been classified into two categories: linear and rotation motors. Recently discovered was a third type of biomotor, including the viral DNA-packaging motor, beside the bacterial DNA translocases, that uses a revolving mechanism without rotation. By analogy, rotation resembles the Earth's rotation on its own axis, while revolving resembles the Earth's revolving around the Sun (see animations at http://rnanano.osu.edu/movie.html). Herein, we review the structures of viral dsDNA-packaging motors, the stoichiometries of motor components, and the motion mechanisms of the motors. All viral dsDNA-packaging motors, including those of dsDNA/dsRNA bacteriophages, adenoviruses, poxviruses, herpesviruses, mimiviruses, megaviruses, pandoraviruses, and pithoviruses, contain a high-stoichiometry machine composed of multiple components that work cooperatively and sequentially. Thus, it is an ideal target for potent drug development based on the power function of the stoichiometries of target complexes that work sequentially.
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Affiliation(s)
- Fengmei Pi
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Zhengyi Zhao
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Venkata Chelikani
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, Canterbury, New Zealand
| | - Kristine Yoder
- Department of Molecular Virology, Immunology, and Medical Genetics, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Mamuka Kvaratskhelia
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
| | - Peixuan Guo
- Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, Department of Physiology and Cell Biology, College of Medicine, and the Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, USA
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32
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Thermodynamic Interrogation of the Assembly of a Viral Genome Packaging Motor Complex. Biophys J 2016; 109:1663-75. [PMID: 26488657 DOI: 10.1016/j.bpj.2015.08.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 08/20/2015] [Accepted: 08/21/2015] [Indexed: 11/21/2022] Open
Abstract
Viral terminase enzymes serve as genome packaging motors in many complex double-stranded DNA viruses. The functional motors are multiprotein complexes that translocate viral DNA into a capsid shell, powered by a packaging ATPase, and are among the most powerful molecular motors in nature. Given their essential role in virus development, the structure and function of these biological motors is of considerable interest. Bacteriophage λ-terminase, which serves as a prototypical genome packaging motor, is composed of one large catalytic subunit tightly associated with two DNA recognition subunits. This protomer assembles into a functional higher-order complex that excises a unit length genome from a concatemeric DNA precursor (genome maturation) and concomitantly translocates the duplex into a preformed procapsid shell (genome packaging). While the enzymology of λ-terminase has been well described, the nature of the catalytically competent nucleoprotein intermediates, and the mechanism describing their assembly and activation, is less clear. Here we utilize analytical ultracentrifugation to determine the thermodynamic parameters describing motor assembly and define a minimal thermodynamic linkage model that describes the effects of salt on protomer assembly into a tetrameric complex. Negative stain electron microscopy images reveal a symmetric ring-like complex with a compact stem and four extended arms that exhibit a range of conformational states. Finally, kinetic studies demonstrate that assembly of the ring tetramer is directly linked to activation of the packaging ATPase activity of the motor, thus providing a direct link between structure and function. The implications of these results with respect to the assembly and activation of the functional packaging motor during a productive viral infection are discussed.
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Hill AC, Bartley LE, Schroeder SJ. Prohead RNA: a noncoding viral RNA of novel structure and function. WILEY INTERDISCIPLINARY REVIEWS. RNA 2016; 7:428-37. [PMID: 26810250 PMCID: PMC5066667 DOI: 10.1002/wrna.1330] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/23/2015] [Accepted: 12/02/2015] [Indexed: 12/12/2022]
Abstract
Prohead RNA (pRNA) is an essential component of the powerful Φ29-like bacteriophage DNA packaging motor. However, the specific role of this unique RNA in the Φ29 packaging motor remains unknown. This review examines pRNA as a noncoding RNA of novel structure and function. In order to highlight the reasons for exploring the structure and function of pRNA, we (1) provide an overview of Φ29-like bacteriophage and the Φ29 DNA packaging motor, including putative motor mechanisms and structures of its component parts; (2) discuss pRNA structure and possible roles for pRNA in the Φ29 packaging motor; (3) summarize pRNA self-assembly; and (4) describe the prospective therapeutic applications of pRNA. Many questions remain to be answered in order to connect what is currently known about pRNA structure to its novel function in the Φ29 packaging motor. The knowledge gained from studying the structure, function, and sequence variation in pRNA will help develop tools to better navigate the conformational landscapes of RNA. WIREs RNA 2016, 7:428-437. doi: 10.1002/wrna.1330 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Alyssa C Hill
- Department of Microbiology and Plant Biology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Laura E Bartley
- Department of Microbiology and Plant Biology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Susan J Schroeder
- Department of Microbiology and Plant Biology, Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
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34
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Hao Y, Kieft JS. Three-way junction conformation dictates self-association of phage packaging RNAs. RNA Biol 2016; 13:635-45. [PMID: 27217219 DOI: 10.1080/15476286.2016.1190075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
The packaging RNA (pRNA) found in the phi29 family of bacteriophage is an essential component of a powerful molecular motor used to package the phage's DNA genome into the capsid. The pRNA forms homomultimers mediated by intermolecular "kissing-loop" interactions, thus it is an example of the unusual phenomenon of a self-associating RNA that can form symmetric higher-order multimers. Previous research showed the pRNAs from phi29 family phages have diverse self-association properties and the kissing-loop interaction is not the sole structural element dictating multimerization. We found that a 3-way junction (3wj) within each pRNA, despite not making direct intermolecular contacts, plays important roles in stabilizing the intermolecular interactions and dictating the size of the multimer formed (dimer, trimer, etc.). Specifically, the 3wj in the pRNA from phage M2 appears to favor a different conformation compared to the 3wj in the phi29 pRNA, and the M2 junction facilitates formation of a higher-order multimer that is more thermostable. This behavior provides insights into the fundamental principles of RNA self-association, and additionally may be useful to engineer fine-tuned properties into pRNAs for nanotechnology.
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Affiliation(s)
- Yumeng Hao
- a Department of Biochemistry and Molecular Genetics , University of Colorado Denver School of Medicine , Aurora , CO , USA
| | - Jeffrey S Kieft
- a Department of Biochemistry and Molecular Genetics , University of Colorado Denver School of Medicine , Aurora , CO , USA
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35
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Shu D, Pi F, Wang C, Zhang P, Guo P. New approach to develop ultra-high inhibitory drug using the power function of the stoichiometry of the targeted nanomachine or biocomplex. Nanomedicine (Lond) 2016; 10:1881-97. [PMID: 26139124 DOI: 10.2217/nnm.15.37] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
AIMS To find methods for potent drug development by targeting to biocomplex with high copy number. METHODS Phi29 DNA packaging motor components with different stoichiometries were used as model to assay virion assembly with Yang Hui's Triangle [Formula: see text], where Z = stoichiometry, M = drugged subunits per biocomplex, p and q are the fraction of drugged and undrugged subunits in the population. RESULTS Inhibition efficiency follows a power function. When number of drugged subunits to block the function of the complex K = 1, the uninhibited biocomplex equals q(z), demonstrating the multiplicative effect of stoichiometry on inhibition with stoichiometry 1000 > 6 > 1. Complete inhibition of virus replication was found when Z = 6. CONCLUSION Drug inhibition potency depends on the stoichiometry of the targeted components of the biocomplex or nanomachine. The inhibition effect follows a power function of the stoichiometry of the target biocomplex.
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Affiliation(s)
- Dan Shu
- Department of Pharmaceutical Sciences, Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
| | - Fengmei Pi
- Department of Pharmaceutical Sciences, Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
| | - Chi Wang
- Department of Biostatistics & Nanobiotechnology Center, University of Kentucky, Lexington, KY 40536, USA
| | - Peng Zhang
- Department of Surgery, University of Michigan Health System, Ann Arbor, MI 48109, USA
| | - Peixuan Guo
- Department of Pharmaceutical Sciences, Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
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36
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Biological Nanomotors with a Revolution, Linear, or Rotation Motion Mechanism. Microbiol Mol Biol Rev 2016; 80:161-86. [PMID: 26819321 DOI: 10.1128/mmbr.00056-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The ubiquitous biological nanomotors were classified into two categories in the past: linear and rotation motors. In 2013, a third type of biomotor, revolution without rotation (http://rnanano.osu.edu/movie.html), was discovered and found to be widespread among bacteria, eukaryotic viruses, and double-stranded DNA (dsDNA) bacteriophages. This review focuses on recent findings about various aspects of motors, including chirality, stoichiometry, channel size, entropy, conformational change, and energy usage rate, in a variety of well-studied motors, including FoF1 ATPase, helicases, viral dsDNA-packaging motors, bacterial chromosome translocases, myosin, kinesin, and dynein. In particular, dsDNA translocases are used to illustrate how these features relate to the motion mechanism and how nature elegantly evolved a revolution mechanism to avoid coiling and tangling during lengthy dsDNA genome transportation in cell division. Motor chirality and channel size are two factors that distinguish rotation motors from revolution motors. Rotation motors use right-handed channels to drive the right-handed dsDNA, similar to the way a nut drives the bolt with threads in same orientation; revolution motors use left-handed motor channels to revolve the right-handed dsDNA. Rotation motors use small channels (<2 nm in diameter) for the close contact of the channel wall with single-stranded DNA (ssDNA) or the 2-nm dsDNA bolt; revolution motors use larger channels (>3 nm) with room for the bolt to revolve. Binding and hydrolysis of ATP are linked to different conformational entropy changes in the motor that lead to altered affinity for the substrate and allow work to be done, for example, helicase unwinding of DNA or translocase directional movement of DNA.
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Pi F, Vieweger M, Zhao Z, Wang S, Guo P. Discovery of a new method for potent drug development using power function of stoichiometry of homomeric biocomplexes or biological nanomotors. Expert Opin Drug Deliv 2015; 13:23-36. [PMID: 26307193 DOI: 10.1517/17425247.2015.1082544] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Multidrug resistance and the appearance of incurable diseases inspire the quest for potent therapeutics. AREAS COVERED We review a new methodology in designing potent drugs by targeting multi-subunit homomeric biological motors, machines or complexes with Z > 1 and K = 1, where Z is the stoichiometry of the target, and K is the number of drugged subunits required to block the function of the complex. The condition is similar to a series electrical circuit of Christmas decorations: failure of one light bulb causes the entire lighting system to lose power. In most multi-subunit, homomeric biological systems, a sequential coordination or cooperative action mechanism is utilized, thus K equals 1. Drug inhibition depends on the ratio of drugged to non-drugged complexes. When K = 1, and Z > 1, the inhibition effect follows a power law with respect to Z, leading to enhanced drug potency. The hypothesis that the potency of drug inhibition depends on the stoichiometry of the targeted biological complexes was recently quantified by Yang-Hui's Triangle (or binomial distribution), and proved using a highly sensitive in vitro phi29 viral DNA packaging system. Examples of targeting homomeric bio-complexes with high stoichiometry for potent drug discovery are discussed. EXPERT OPINION Biomotors with multiple subunits are widespread in viruses, bacteria and cells, making this approach generally applicable in the development of inhibition drugs with high efficiency.
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Affiliation(s)
- Fengmei Pi
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Mario Vieweger
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Zhengyi Zhao
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Shaoying Wang
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
| | - Peixuan Guo
- a 1 University of Kentucky, Nanobiotechnology Center , Lexington, KY 40536, USA.,b 2 University of Kentucky, Markey Cancer Center , Lexington, KY 40536, USA.,c 3 University of Kentucky, Department of Pharmaceutical Sciences , 789 S. Limestone Street, Room # 576, Lexington, KY 40536, USA +1 859 218 0128 ; +1 859 257 1307 ;
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Rinaldi AJ, Suddala KC, Walter NG. Native purification and labeling of RNA for single molecule fluorescence studies. Methods Mol Biol 2015; 1240:63-95. [PMID: 25352138 DOI: 10.1007/978-1-4939-1896-6_6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The recent discovery that non-coding RNAs are considerably more abundant and serve a much wider range of critical cellular functions than recognized over previous decades of research into molecular biology has sparked a renewed interest in the study of structure-function relationships of RNA. To perform their functions in the cell, RNAs must dominantly adopt their native conformations, avoiding deep, non-productive kinetic traps that may exist along a frustrated (rugged) folding free energy landscape. Intracellularly, RNAs are synthesized by RNA polymerase and fold co-transcriptionally starting from the 5' end, sometimes with the aid of protein chaperones. By contrast, in the laboratory RNAs are commonly generated by in vitro transcription or chemical synthesis, followed by purification in a manner that includes the use of high concentrations of urea, heat and UV light (for detection), resulting in the denaturation and subsequent refolding of the entire RNA. Recent studies into the nature of heterogeneous RNA populations resulting from this process have underscored the need for non-denaturing (native) purification methods that maintain the co-transcriptional fold of an RNA. Here, we present protocols for the native purification of an RNA after its in vitro transcription and for fluorophore and biotin labeling methods designed to preserve its native conformation for use in single molecule fluorescence resonance energy transfer (smFRET) inquiries into its structure and function. Finally, we present methods for taking smFRET data and for analyzing them, as well as a description of plausible overall preparation schemes for the plethora of non-coding RNAs.
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Affiliation(s)
- Arlie J Rinaldi
- W. M. Keck Science Center, The Claremont Colleges, Claremont, CA, 91711, USA
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Coban O, Zanetti-Dominguez LC, Matthews DR, Rolfe DJ, Weitsman G, Barber PR, Barbeau J, Devauges V, Kampmeier F, Winn M, Vojnovic B, Parker PJ, Lidke KA, Lidke DS, Ameer-Beg SM, Martin-Fernandez ML, Ng T. Effect of phosphorylation on EGFR dimer stability probed by single-molecule dynamics and FRET/FLIM. Biophys J 2015; 108:1013-26. [PMID: 25762314 PMCID: PMC4375452 DOI: 10.1016/j.bpj.2015.01.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 12/06/2014] [Accepted: 01/07/2015] [Indexed: 12/22/2022] Open
Abstract
Deregulation of epidermal growth factor receptor (EGFR) signaling has been correlated with the development of a variety of human carcinomas. EGF-induced receptor dimerization and consequent trans- auto-phosphorylation are among the earliest events in signal transduction. Binding of EGF is thought to induce a conformational change that consequently unfolds an ectodomain loop required for dimerization indirectly. It may also induce important allosteric changes in the cytoplasmic domain. Despite extensive knowledge on the physiological activation of EGFR, the effect of targeted therapies on receptor conformation is not known and this particular aspect of receptor function, which can potentially be influenced by drug treatment, may in part explain the heterogeneous clinical response among cancer patients. Here, we used Förster resonance energy transfer/fluorescence lifetime imaging microscopy (FRET/FLIM) combined with two-color single-molecule tracking to study the effect of ATP-competitive small molecule tyrosine kinase inhibitors (TKIs) and phosphatase-based manipulation of EGFR phosphorylation on live cells. The distribution of dimer on-times was fitted to a monoexponential to extract dimer off-rates (koff). Our data show that pretreatment with gefitinib (active conformation binder) stabilizes the EGFR ligand-bound homodimer. Overexpression of EGFR-specific DEP-1 phosphatase was also found to have a stabilizing effect on the homodimer. No significant difference in the koff of the dimer could be detected when an anti-EGFR antibody (425 Snap single-chain variable fragment) that allows for dimerization of ligand-bound receptors, but not phosphorylation, was used. These results suggest that both the conformation of the extracellular domain and phosphorylation status of the receptor are involved in modulating the stability of the dimer. The relative fractions of these two EGFR subpopulations (interacting versus free) were obtained by a fractional-intensity analysis of ensemble FRET/FLIM images. Our combined imaging approach showed that both the fraction and affinity (surrogate of conformation at a single-molecule level) increased after gefitinib pretreatment or DEP-1 phosphatase overexpression. Using an EGFR mutation (I706Q, V948R) that perturbs the ability of EGFR to dimerize intracellularly, we showed that a modest drug-induced increase in the fraction/stability of the EGFR homodimer may have a significant biological impact on the tumor cell's proliferation potential.
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Affiliation(s)
- Oana Coban
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK.
| | - Laura C Zanetti-Dominguez
- Science and Technology Facilities Council, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, UK
| | - Daniel R Matthews
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK
| | - Daniel J Rolfe
- Science and Technology Facilities Council, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, UK
| | - Gregory Weitsman
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK
| | - Paul R Barber
- Gray Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Oxford, UK
| | - Jody Barbeau
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK
| | - Viviane Devauges
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK
| | - Florian Kampmeier
- Division of Imaging Sciences, King's College London, The Rayne Institute, St. Thomas Hospital, London, UK
| | - Martyn Winn
- Computational Science and Engineering Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, UK
| | - Borivoj Vojnovic
- Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK; Gray Institute for Radiation Oncology & Biology, Department of Oncology, University of Oxford, Oxford, UK
| | - Peter J Parker
- Division of Cancer Studies, King's College London, London, UK; Cancer Research UK, London Research Institute, London, UK
| | - Keith A Lidke
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico
| | - Diane S Lidke
- Department of Pathology, University of New Mexico School of Medicine, Albuquerque, New Mexico; Cancer Research and Treatment Center, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - Simon M Ameer-Beg
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK; Division of Cancer Studies, King's College London, London, UK
| | - Marisa L Martin-Fernandez
- Science and Technology Facilities Council, Research Complex at Harwell, Rutherford Appleton Laboratory, Didcot, UK
| | - Tony Ng
- Richard Dimbleby Department of Cancer Research, King's College London, London, UK; Randall Division of Cellular and Molecular Biophysics, King's College London, London, UK; Division of Cancer Studies, King's College London, London, UK
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Hariri AA, Hamblin GD, Gidi Y, Sleiman HF, Cosa G. Stepwise growth of surface-grafted DNA nanotubes visualized at the single-molecule level. Nat Chem 2015; 7:295-300. [DOI: 10.1038/nchem.2184] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Accepted: 01/15/2015] [Indexed: 11/09/2022]
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Common mechanisms of DNA translocation motors in bacteria and viruses using one-way revolution mechanism without rotation. Biotechnol Adv 2015; 32:853-72. [PMID: 24913057 DOI: 10.1016/j.biotechadv.2014.01.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 01/24/2014] [Accepted: 01/25/2014] [Indexed: 12/15/2022]
Abstract
Biomotors were once described into two categories: linear motor and rotation motor. Recently, a third type of biomotor with revolution mechanism without rotation has been discovered. By analogy, rotation resembles the Earth rotating on its axis in a complete cycle every 24h, while revolution resembles the Earth revolving around the Sun one circle per 365 days (see animations http://nanobio.uky.edu/movie.html). The action of revolution that enables a motor free of coiling and torque has solved many puzzles and debates that have occurred throughout the history of viral DNA packaging motor studies. It also settles the discrepancies concerning the structure, stoichiometry, and functioning of DNA translocation motors. This review uses bacteriophages Phi29, HK97, SPP1, P22, T4, and T7 as well as bacterial DNA translocase FtsK and SpoIIIE or the large eukaryotic dsDNA viruses such as mimivirus and vaccinia virus as examples to elucidate the puzzles. These motors use ATPase, some of which have been confirmed to be a hexamer, to revolve around the dsDNA sequentially. ATP binding induces conformational change and possibly an entropy alteration in ATPase to a high affinity toward dsDNA; but ATP hydrolysis triggers another entropic and conformational change in ATPase to a low affinity for DNA, by which dsDNA is pushed toward an adjacent ATPase subunit. The rotation and revolution mechanisms can be distinguished by the size of channel: the channels of rotation motors are equal to or smaller than 2 nm, that is the size of dsDNA, whereas channels of revolution motors are larger than 3 nm. Rotation motors use parallel threads to operate with a right-handed channel, while revolution motors use a left-handed channel to drive the right-handed DNA in an anti-chiral arrangement. Coordination of several vector factors in the same direction makes viral DNA-packaging motors unusually powerful and effective. Revolution mechanism that avoids DNA coiling in translocating the lengthy genomic dsDNA helix could be advantageous for cell replication such as bacterial binary fission and cell mitosis without the need for topoisomerase or helicase to consume additional energy.
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Afonin KA, Lindsay B, Shapiro BA. Engineered RNA Nanodesigns for Applications in RNA Nanotechnology. DNA AND RNA NANOTECHNOLOGY 2015; 1:1-15. [PMID: 34322585 PMCID: PMC8315564 DOI: 10.2478/rnan-2013-0001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Nucleic acids have emerged as an extremely promising platform for nanotechnological applications because of their unique biochemical properties and functions. RNA, in particular, is characterized by relatively high thermal stability, diverse structural flexibility, and its capacity to perform a variety of functions in nature. These properties make RNA a valuable platform for bio-nanotechnology, specifically RNA Nanotechnology, that can create de novo nanostructures with unique functionalities through the design, integration, and re-engineering of powerful mechanisms based on a variety of existing RNA structures and their fundamental biochemical properties. This review highlights the principles that underlie the rational design of RNA nanostructures, describes the main strategies used to construct self-assembling nanoparticles, and discusses the challenges and possibilities facing the application of RNA Nanotechnology in the future.
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Affiliation(s)
- Kirill A. Afonin
- Center for Cancer Research Nanobiology Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Brian Lindsay
- Center for Cancer Research Nanobiology Program, National Cancer Institute, Frederick, MD 21702, USA
| | - Bruce A. Shapiro
- Center for Cancer Research Nanobiology Program, National Cancer Institute, Frederick, MD 21702, USA
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Guo P. Biophysical studies reveal new evidence for one-way revolution mechanism of bacteriophage ϕ29 DNA packaging motor. Biophys J 2014; 106:1837-8. [PMID: 24806913 DOI: 10.1016/j.bpj.2014.03.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/28/2014] [Accepted: 03/31/2014] [Indexed: 11/18/2022] Open
Affiliation(s)
- Peixuan Guo
- Nanobiotechnology Center, Markey Cancer Center, and College of Pharmacy, University of Kentucky, Lexington, Kentucky.
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Hao Y, Kieft JS. Diverse self-association properties within a family of phage packaging RNAs. RNA (NEW YORK, N.Y.) 2014; 20:1759-74. [PMID: 25246655 PMCID: PMC4201828 DOI: 10.1261/rna.045948.114] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/18/2014] [Indexed: 05/24/2023]
Abstract
The packaging RNA (pRNA) found in phi29 bacteriophage is an essential component of a molecular motor that packages the phage's DNA genome. The pRNA forms higher-order multimers by intermolecular "kissing" interactions between identical molecules. The phi29 pRNA is a proven building block for nanotechnology and a model to explore the rare phenomenon of naturally occurring RNA self-association. Although the self-association properties of the phi29 pRNA have been extensively studied and this pRNA is used in nanotechnology, the characteristics of phylogenetically related pRNAs with divergent sequences are comparatively underexplored. These diverse pRNAs may lend new insight into both the rules governing RNA self-association and for RNA engineering. Therefore, we used a combination of biochemical and biophysical methods to resolve ambiguities in the proposed secondary structures of pRNAs from M2, GA1, SF5, and B103 phage, and to discover that different naturally occurring pRNAs form multimers of different stoichiometry and thermostability. Indeed, the M2 pRNA formed multimers that were particularly thermostable and may be more useful than phi29 pRNA for many applications. To determine if diverse pRNA behaviors are conferred by different kissing loop sequences, we designed and tested chimeric RNAs based on our revised secondary structural models. We found that although the kissing loops are essential for self-association, the critical determinant of multimer stability and stoichiometry is likely the diverse three-way junctions found in these RNAs. Using known features of RNA three-way junctions and solved structures of phi29 pRNA's junction, we propose a model for how different junctions affect self-association.
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Affiliation(s)
- Yumeng Hao
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, School of Medicine, Aurora, Colorado 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, School of Medicine, Aurora, Colorado 80045, USA Howard Hughes Medical Institute, University of Colorado Denver, School of Medicine, Aurora, Colorado 80045, USA
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Single-molecule packaging initiation in real time by a viral DNA packaging machine from bacteriophage T4. Proc Natl Acad Sci U S A 2014; 111:15096-101. [PMID: 25288726 DOI: 10.1073/pnas.1407235111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Viral DNA packaging motors are among the most powerful molecular motors known. A variety of structural, biochemical, and single-molecule biophysical approaches have been used to understand their mechanochemistry. However, packaging initiation has been difficult to analyze because of its transient and highly dynamic nature. Here, we developed a single-molecule fluorescence assay that allowed visualization of packaging initiation and reinitiation in real time and quantification of motor assembly and initiation kinetics. We observed that a single bacteriophage T4 packaging machine can package multiple DNA molecules in bursts of activity separated by long pauses, suggesting that it switches between active and quiescent states. Multiple initiation pathways were discovered including, unexpectedly, direct DNA binding to the capsid portal followed by recruitment of motor subunits. Rapid succession of ATP hydrolysis was essential for efficient initiation. These observations have implications for the evolution of icosahedral viruses and regulation of virus assembly.
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De-Donatis GM, Zhao Z, Wang S, Huang LP, Schwartz C, Tsodikov OV, Zhang H, Haque F, Guo P. Finding of widespread viral and bacterial revolution dsDNA translocation motors distinct from rotation motors by channel chirality and size. Cell Biosci 2014; 4:30. [PMID: 24940480 PMCID: PMC4060578 DOI: 10.1186/2045-3701-4-30] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 05/16/2014] [Indexed: 12/03/2022] Open
Abstract
Background Double-stranded DNA translocation is ubiquitous in living systems. Cell mitosis, bacterial binary fission, DNA replication or repair, homologous recombination, Holliday junction resolution, viral genome packaging and cell entry all involve biomotor-driven dsDNA translocation. Previously, biomotors have been primarily classified into linear and rotational motors. We recently discovered a third class of dsDNA translocation motors in Phi29 utilizing revolution mechanism without rotation. Analogically, the Earth rotates around its own axis every 24 hours, but revolves around the Sun every 365 days. Results Single-channel DNA translocation conductance assay combined with structure inspections of motor channels on bacteriophages P22, SPP1, HK97, T7, T4, Phi29, and other dsDNA translocation motors such as bacterial FtsK and eukaryotic mimiviruses or vaccinia viruses showed that revolution motor is widespread. The force generation mechanism for revolution motors is elucidated. Revolution motors can be differentiated from rotation motors by their channel size and chirality. Crystal structure inspection revealed that revolution motors commonly exhibit channel diameters larger than 3 nm, while rotation motors that rotate around one of the two separated DNA strands feature a diameter smaller than 2 nm. Phi29 revolution motor translocated double- and tetra-stranded DNA that occupied 32% and 64% of the narrowest channel cross-section, respectively, evidencing that revolution motors exhibit channel diameters significantly wider than the dsDNA. Left-handed oriented channels found in revolution motors drive the right-handed dsDNA via anti-chiral interaction, while right-handed channels observed in rotation motors drive the right-handed dsDNA via parallel threads. Tethering both the motor and the dsDNA distal-end of the revolution motor does not block DNA packaging, indicating that no rotation is required for motors of dsDNA phages, while a small-angle left-handed twist of dsDNA that is aligned with the channel could occur due to the conformational change of the phage motor channels from a left-handed configuration for DNA entry to a right-handed configuration for DNA ejection for host cell infection. Conclusions The revolution motor is widespread among biological systems, and can be distinguished from rotation motors by channel size and chirality. The revolution mechanism renders dsDNA void of coiling and torque during translocation of the lengthy helical chromosome, thus resulting in more efficient motor energy conversion.
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Affiliation(s)
- Gian Marco De-Donatis
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Zhengyi Zhao
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Shaoying Wang
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Lisa P Huang
- Current address: Institute for Biomarker Research, Medical Diagnostic Laboratories, L.L.C., Hamilton, NJ 08690, USA
| | - Chad Schwartz
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Oleg V Tsodikov
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Hui Zhang
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Farzin Haque
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA
| | - Peixuan Guo
- Nanobiotechnology Center, University of Kentucky, Lexington, KY, USA.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA.,Markey Cancer Center, University of Kentucky, Lexington, KY, USA.,William Farish Endowed Chair in Nanobiotechnology, School of Pharmacy, University of Kentucky, 565 Biopharmaceutical Complex, 789 S. Limestone Street, Lexington, KY 40536, USA
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Soundararajan HC, Bullock SL. The influence of dynein processivity control, MAPs, and microtubule ends on directional movement of a localising mRNA. eLife 2014; 3:e01596. [PMID: 24737859 PMCID: PMC3985186 DOI: 10.7554/elife.01596] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Many cellular constituents travel along microtubules in association with multiple copies of motor proteins. How the activity of these motors is regulated during cargo sorting is poorly understood. In this study, we address this issue using a novel in vitro assay for the motility of localising Drosophila mRNAs bound to native dynein-dynactin complexes. High precision tracking reveals that individual RNPs within a population undergo either diffusive, or highly processive, minus end-directed movements along microtubules. RNA localisation signals stimulate the processive movements, with regulation of dynein-dynactin’s activity rather than its total copy number per RNP, responsible for this effect. Our data support a novel mechanism for multi-motor translocation based on the regulation of dynein processivity by discrete cargo-associated features. Studying the in vitro responses of RNPs to microtubule-associated proteins (MAPs) and microtubule ends provides insights into how an RNA population could navigate the cytoskeletal network and become anchored at its destination in cells. DOI:http://dx.doi.org/10.7554/eLife.01596.001 For a cell to do its job, the different components inside it need to be moved to different locations. This is achieved by an elaborate cellular transport system. To move a component to where it needs to be, motor proteins bind to it, often with the assistance of other ‘accessory’ proteins. This cargo-motor complex then moves along a network of tracks within the cell. Viruses also exploit this transport system in order to be trafficked to specific parts of the cell during their life cycles. Many cargos are moved along microtubule tracks. Multiple microtubule motor proteins often attach to the same cargo, but it is unclear how they work together during transport. Previous studies have attempted to address this issue by attaching motor proteins to artificial cargoes, such as synthetic beads. However, these experiments did not include some of the accessory proteins that are thought to play a role during transport within the living cell. Soundararajan and Bullock have now examined how complexes containing multiple motors bound to accessory proteins move molecules of messenger RNA to specific sites within cells. By visualising fruit fly mRNA moving along microtubules attached to a glass surface, the transport process can be studied in detail. It appears that the complexes travel using one of two methods: they either diffuse along the microtubules, which they can do in either direction, or they power themselves along the microtubules, which they can only do in one direction. Although previous experiments with artificial cargos suggested that the number of motors in the complex determines the likelihood of one-way traffic, it appears that one or more accessory proteins are actually in control during mRNA transport. Soundararajan and Bullock also documented how the mRNA-motor complexes react to roadblocks and dead-ends on the microtubule highway. Rather than letting go of the microtubule upon such an encounter, the complexes can reverse back down the track. This behaviour may help them to find a new route to their destination. DOI:http://dx.doi.org/10.7554/eLife.01596.002
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Shu Y, Pi F, Sharma A, Rajabi M, Haque F, Shu D, Leggas M, Evers BM, Guo P. Stable RNA nanoparticles as potential new generation drugs for cancer therapy. Adv Drug Deliv Rev 2014; 66:74-89. [PMID: 24270010 DOI: 10.1016/j.addr.2013.11.006] [Citation(s) in RCA: 181] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 10/11/2013] [Accepted: 11/13/2013] [Indexed: 12/13/2022]
Abstract
Human genome sequencing revealed that only ~1.5% of the DNA sequence coded for proteins. More and more evidence has uncovered that a substantial part of the 98.5% so-called "junk" DNAs actually code for noncoding RNAs. Two milestones, chemical drugs and protein drugs, have already appeared in the history of drug development, and it is expected that the third milestone in drug development will be RNA drugs or drugs that target RNA. This review focuses on the development of RNA therapeutics for potential cancer treatment by applying RNA nanotechnology. A therapeutic RNA nanoparticle is unique in that its scaffold, ligand, and therapeutic component can all be composed of RNA. The special physicochemical properties lend to the delivery of siRNA, miRNA, ribozymes, or riboswitches; imaging using fluogenenic RNA; and targeting using RNA aptamers. With recent advances in solving the chemical, enzymatic, and thermodynamic stability issues, RNA nanoparticles have been found to be advantageous for in vivo applications due to their uniform nano-scale size, precise stoichiometry, polyvalent nature, low immunogenicity, low toxicity, and target specificity. In vivo animal studies have revealed that RNA nanoparticles can specifically target tumors with favorable pharmacokinetic and pharmacodynamic parameters without unwanted accumulation in normal organs. This review summarizes the key studies that have led to the detailed understanding of RNA nanoparticle formation as well as chemical and thermodynamic stability issue. The methods for RNA nanoparticle construction, and the current challenges in the clinical application of RNA nanotechnology, such as endosome trapping and production costs, are also discussed.
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Affiliation(s)
- Yi Shu
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Fengmei Pi
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Ashwani Sharma
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Mehdi Rajabi
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Farzin Haque
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Dan Shu
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Markos Leggas
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - B Mark Evers
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA
| | - Peixuan Guo
- Markey Cancer Center, University of Kentucky, Lexington, KY 40536, USA; Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA.
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49
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Arant RJ, Ulbrich MH. Deciphering the subunit composition of multimeric proteins by counting photobleaching steps. Chemphyschem 2014; 15:600-5. [PMID: 24481650 DOI: 10.1002/cphc.201301092] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Indexed: 12/28/2022]
Abstract
The limit of subdiffraction imaging with fluorescent proteins currently lies at 20 nm, and therefore most protein complexes are too small (2-5 nm) to spatially resolve their individual subunits by optical means. However, the number and stoichiometry of subunits within an immobilized protein complex can be resolved by the observation of photobleaching steps of individual fluorophores or co-localization of single-molecule fluorescence emission in multiple colors. We give an overview of the proteins that have been investigated by this approach and the different techniques that can be used to immobilize and label the proteins. This minireview should serve as a guideline for scientists who want to employ single-molecule subunit counting for their research.
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Affiliation(s)
- Ryan J Arant
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720 (USA)
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50
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Zhang H, Guo P. Single molecule photobleaching (SMPB) technology for counting of RNA, DNA, protein and other molecules in nanoparticles and biological complexes by TIRF instrumentation. Methods 2014; 67:169-76. [PMID: 24440482 DOI: 10.1016/j.ymeth.2014.01.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/28/2013] [Accepted: 01/08/2014] [Indexed: 11/25/2022] Open
Abstract
Direct counting of biomolecules within biological complexes or nanomachines is demanding. Single molecule counting using optical microscopy is challenging due to the diffraction limit. The single molecule photobleaching (SMPB) technology for direct counting developed by our team (Shu et al., 2007 [18]; Zhang et al., 2007 [19]) offers a simple and straightforward method to determine the stoichiometry of molecules or subunits within biocomplexes or nanomachines at nanometer scales. Stoichiometry is determined by real-time observation of the number of descending steps resulted from the photobleaching of individual fluorophore. This technology has now been used extensively for single molecule counting of protein, RNA, and other macromolecules in a variety of complexes or nanostructures. Here, we elucidate the SMPB technology, using the counting of RNA molecules within a bacteriophage phi29 DNA-packaging biomotor as an example. The method described here can be applied to the single molecule counting of other molecules in other systems. The construction of a concise, simple and economical single molecule total internal reflection fluorescence (TIRF) microscope combining prism-type and objective-type TIRF is described. The imaging system contains a deep-cooled sensitive EMCCD camera with single fluorophore detection sensitivity, a laser combiner for simultaneous dual-color excitation, and a Dual-View™ imager to split the multiple outcome signals to different detector channels based on their wavelengths. Methodology of the single molecule photobleaching assay used to elucidate the stoichiometry of RNA on phi29 DNA packaging motor and the mechanism of protein/RNA interaction are described. Different methods for single fluorophore labeling of RNA molecules are reviewed. The process of statistical modeling to reveal the true copy number of the biomolecules based on binomial distribution is also described.
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Affiliation(s)
- Hui Zhang
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA.
| | - Peixuan Guo
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA.
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