1
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Zhou EC, Fu H, Wang HZ, Yang YJ, Zhang XH. Converting Multiple- to Single-DNA-Tethered Beads and Removing Only-One-End-Tethered DNA in High-Throughput Stretching. ACS Sens 2024. [PMID: 39424335 DOI: 10.1021/acssensors.4c02585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2024]
Abstract
S-DNA is a double-stranded DNA that forms under tensions of >65 pN. Here, we report that S-DNA resists the cleavage of Cas12a and the restriction endonuclease SmaI. Taking advantage of this resistance, in magnetic tweezer experiments, we developed an assay to convert multiple-DNA-tethered beads into single-DNA-tethered beads and remove the only-one-end-tethered DNA molecule by cleaving the DNA that does not transition to S-DNA at about 80 pN. When multiple DNA molecules are tethered to a single bead, they share the tension, exist in the B-form, and allow the cleavage. Only-one-end-tethered DNA molecules, free of tension, are also cleaved. In versatile types of experiments, we proved the broad applications of this assay: measuring the correct DNA elasticity and DNA condensation dynamics by avoiding the false results due to interference of only-one-end-tethered DNA molecules and quantifying the accurate cleavage rates of Cas12a and the restriction endonucleases by eliminating the error caused by multiple-DNA-tethered beads. This convenient assay ensures correct and accurate results in high-throughput DNA stretching experiments.
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Affiliation(s)
- Er-Chi Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Hang Fu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hao-Ze Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ya-Jun Yang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xing-Hua Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
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2
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Bauer MS, Gruber S, Hausch A, Melo MCR, Gomes PSFC, Nicolaus T, Milles LF, Gaub HE, Bernardi RC, Lipfert J. Single-molecule force stability of the SARS-CoV-2-ACE2 interface in variants-of-concern. NATURE NANOTECHNOLOGY 2024; 19:399-405. [PMID: 38012274 DOI: 10.1038/s41565-023-01536-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 09/26/2023] [Indexed: 11/29/2023]
Abstract
Mutations in SARS-CoV-2 have shown effective evasion of population immunity and increased affinity to the cellular receptor angiotensin-converting enzyme 2 (ACE2). However, in the dynamic environment of the respiratory tract, forces act on the binding partners, which raises the question of whether not only affinity but also force stability of the SARS-CoV-2-ACE2 interaction might be a selection factor for mutations. Using magnetic tweezers, we investigate the impact of amino acid substitutions in variants of concern (Alpha, Beta, Gamma and Delta) and on force-stability and bond kinetic of the receptor-binding domain-ACE2 interface at a single-molecule resolution. We find a higher affinity for all of the variants of concern (>fivefold) compared with the wild type. In contrast, Alpha is the only variant of concern that shows higher force stability (by 17%) compared with the wild type. Using molecular dynamics simulations, we rationalize the mechanistic molecular origins of this increase in force stability. Our study emphasizes the diversity of contributions to the transmissibility of variants and establishes force stability as one of the several factors for fitness. Understanding fitness advantages opens the possibility for the prediction of probable mutations, allowing a rapid adjustment of therapeutics, vaccines and intervention measures.
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Affiliation(s)
- Magnus S Bauer
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany
- Department of Chemical Engineering, Stanford University, Stanford, CA, USA
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Sophia Gruber
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany
| | - Adina Hausch
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany
- Center for Protein Assemblies, TUM School of Natural Sciences, Technical University of Munich, Munich, Germany
| | | | | | - Thomas Nicolaus
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany
| | - Lukas F Milles
- Department of Biochemistry, University of Washington, Seattle, WA, USA
- Institute for Protein Design, University of Washington, Seattle, WA, USA
| | - Hermann E Gaub
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany
| | | | - Jan Lipfert
- Department of Physics and Center for NanoScience (CeNS), LMU Munich, Munich, Germany.
- Department of Physics and Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands.
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3
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Stransky F, Kostrz D, Follenfant M, Pomplun S, Meyners C, Strick T, Hausch F, Gosse C. Use of DNA forceps to measure receptor-ligand dissociation equilibrium constants in a single-molecule competition assay. Methods Enzymol 2024; 694:51-82. [PMID: 38492958 DOI: 10.1016/bs.mie.2024.01.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2024]
Abstract
The ability of biophysicists to decipher the behavior of individual biomolecules has steadily improved over the past thirty years. However, it still remains unclear how an ensemble of data acquired at the single-molecule level compares with the data acquired on an ensemble of the same molecules. We here propose an assay to tackle this question in the context of dissociation equilibrium constant measurements. A sensor is built by engrafting a receptor and a ligand onto a flexible dsDNA scaffold and mounting this assembly on magnetic tweezers. This way, looking at the position of the magnetic bead enables one to determine in real-time if the two molecular partners are associated or not. Next, to quantify the affinity of the scrutinized single-receptor for a given competitor, various amounts of the latter molecule are introduced in solution and the equilibrium response of the sensor is monitored throughout the titration protocol. Proofs of concept are established for the binding of three rapamycin analogs to the FKBP12 cis-trans prolyl isomerase. For each of these drugs the mean affinity constant obtained on a ten of individual receptors agrees with the one previously determined in a bulk assay. Furthermore, experimental contingencies are sufficient to explain the dispersion observed over the single-molecule values.
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Affiliation(s)
- François Stransky
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Dorota Kostrz
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Maryne Follenfant
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Sebastian Pomplun
- Leiden Academic Centre for Drug Research, Leiden University, Leiden, The Netherlands
| | - Christian Meyners
- Department of Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
| | - Terence Strick
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France
| | - Felix Hausch
- Department of Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany; Centre for Synthetic Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Charlie Gosse
- Institut de Biologie de l'Ecole Normale Supérieure, ENS, CNRS, INSERM, PSL Research University, Paris, France.
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4
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Schellnhuber K, Blass J, Hübner H, Gallei M, Bennewitz R. Single-Polymer Friction Force Microscopy of dsDNA Interacting with a Nanoporous Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:968-974. [PMID: 38117751 PMCID: PMC10786032 DOI: 10.1021/acs.langmuir.3c03190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/01/2023] [Accepted: 12/11/2023] [Indexed: 12/22/2023]
Abstract
Surface-grafted polymers can reduce friction between solids in liquids by compensating the normal load with osmotic pressure, but they can also contribute to friction when fluctuating polymers entangle with the sliding counter face. We have measured forces acting on a single fluctuating double-stranded DNA polymer, which is attached to the tip of an atomic force microscope and interacts intermittently with nanometer-scale methylated pores of a self-assembled polystyrene-block-poly(4-vinylpyridine) membrane. Rare binding of the polymer into the pores is followed by a stretching of the polymer between the laterally moving tip and the surface and by a force-induced detachment. We present results for the velocity dependence of detachment forces and of attachment frequency and discuss them in terms of rare excursions of the polymer beyond its equilibrium configuration.
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Affiliation(s)
- Kordula Schellnhuber
- INM—Leibniz
Institute for New Materials, 66123 Saarbrücken, Germany
- Department
of Physics, Saarland University, 66123 Saarbrücken, Germany
| | - Johanna Blass
- INM—Leibniz
Institute for New Materials, 66123 Saarbrücken, Germany
| | - Hanna Hübner
- Polymer
Chemistry, Saarland University, 66123 Saarbrücken, Germany
| | - Markus Gallei
- Polymer
Chemistry, Saarland University, 66123 Saarbrücken, Germany
- Saarene,
Saarland Center of Energy Materials and Sustainability, 66123 Saarbrücken, Germany
| | - Roland Bennewitz
- INM—Leibniz
Institute for New Materials, 66123 Saarbrücken, Germany
- Department
of Physics, Saarland University, 66123 Saarbrücken, Germany
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5
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Taris KKH, Kamsma D, Wuite GJL. Single-Cell Measurements Using Acoustic Force Spectroscopy (AFS). Methods Mol Biol 2024; 2694:467-477. [PMID: 37824018 DOI: 10.1007/978-1-0716-3377-9_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
Single-molecule force spectroscopy is a powerful tool to investigate the forces and motions related to interactions of biological molecules. Acoustic force spectroscopy (AFS) is a developed measurement tool to study single molecules or cells making use of acoustic standing waves. AFS permits high experimental throughput because many individual molecules can be manipulated and tracked in parallel. Moreover, a wide range of forces can be applied as well as a force loading rate with range of six orders of magnitude. At the same time, AFS stands out because of its simplicity and the compactness of the experimental setup. Even though the AFS setup is simple, it can still be challenging to perform high-quality measurements. Here we describe, in detail, how to setup, perform, and analyze an AFS measurement to determine cell adhesion.
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Affiliation(s)
- Kees-Karel H Taris
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Douwe Kamsma
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- LUMICKS B.V, Amsterdam, The Netherlands
| | - Gijs J L Wuite
- LaserLaB Amsterdam and Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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6
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Lewis JS, van Oijen AM, Spenkelink LM. Embracing Heterogeneity: Challenging the Paradigm of Replisomes as Deterministic Machines. Chem Rev 2023; 123:13419-13440. [PMID: 37971892 PMCID: PMC10790245 DOI: 10.1021/acs.chemrev.3c00436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 10/15/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
The paradigm of cellular systems as deterministic machines has long guided our understanding of biology. Advancements in technology and methodology, however, have revealed a world of stochasticity, challenging the notion of determinism. Here, we explore the stochastic behavior of multi-protein complexes, using the DNA replication system (replisome) as a prime example. The faithful and timely copying of DNA depends on the simultaneous action of a large set of enzymes and scaffolding factors. This fundamental cellular process is underpinned by dynamic protein-nucleic acid assemblies that must transition between distinct conformations and compositional states. Traditionally viewed as a well-orchestrated molecular machine, recent experimental evidence has unveiled significant variability and heterogeneity in the replication process. In this review, we discuss recent advances in single-molecule approaches and single-particle cryo-EM, which have provided insights into the dynamic processes of DNA replication. We comment on the new challenges faced by structural biologists and biophysicists as they attempt to describe the dynamic cascade of events leading to replisome assembly, activation, and progression. The fundamental principles uncovered and yet to be discovered through the study of DNA replication will inform on similar operating principles for other multi-protein complexes.
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Affiliation(s)
- Jacob S. Lewis
- Macromolecular
Machines Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
| | - Antoine M. van Oijen
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Lisanne M. Spenkelink
- Molecular
Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, New South Wales 2522, Australia
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7
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Zou Z, Liang J, Jia Q, Bai D, Xie W, Wu W, Tan C, Ma J. A versatile and high-throughput flow-cell system combined with fluorescence imaging for simultaneous single-molecule force measurement and visualization. NANOSCALE 2023; 15:17443-17454. [PMID: 37859523 DOI: 10.1039/d3nr03214k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
A flow-cell offers many advantages for single-molecule studies. But, its merit as a quantitative single-molecule tool has long been underestimated. In this work, we developed a gas-pumped fully calibrated flow-cell system combined with fluorescence imaging for simultaneous single-molecule force measurement and visualization. Such a flow-cell system has considered the hydrodynamic drags on biomolecules and hence can apply and measure force up to more than 100 pN in sub-pN precision with an ultra-high force stability (force drift <0.01 pN in 10 minutes) and tuning accuracy (∼0.04 pN). Meanwhile, it also allows acquiring force signals and fluorescence images at the same time, parallelly tracking hundreds of protein motors in real time as well as monitoring the conformational changes of biomolecules under a well-controlled force, as demonstrated by a series of single-molecule experiments in this work, including the studies of DNA overstretching dynamics, transcription under force and DNA folding/unfolding dynamics. Interesting findings, such as the very tight association of single-stranded binding (SSB) proteins with ssDNA and the reversed transcription, have also been made. These results together lay down an essential foundation for a flow-cell to be used as a versatile, quantitative and high-throughput tool for single-molecule manipulation and visualization.
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Affiliation(s)
- Zhenyu Zou
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jialun Liang
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Qian Jia
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, 510006, P.R. China
| | - Di Bai
- School of Life Sciences, State Key Laboratory of Crop Stress Adaptation and Improvement, Henan University, Kaifeng 475001, P.R. China
| | - Wei Xie
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, Guangdong, 510006, P.R. China
| | - Wenqiang Wu
- School of Life Sciences, State Key Laboratory of Crop Stress Adaptation and Improvement, Henan University, Kaifeng 475001, P.R. China
| | - Chuang Tan
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
| | - Jie Ma
- School of Physics, Sun Yat-sen University, Guangzhou 510275, P.R. China.
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, P.R. China
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8
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Luo Y, Chang J, Yang D, Bryan JS, MacIsaac M, Pressé S, Wong WP. Resolving Molecular Heterogeneity with Single-Molecule Centrifugation. J Am Chem Soc 2023; 145:3276-3282. [PMID: 36716175 PMCID: PMC9936575 DOI: 10.1021/jacs.2c11450] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
For many classes of biomolecules, population-level heterogeneity is an essential aspect of biological function─from antibodies produced by the immune system to post-translationally modified proteins that regulate cellular processes. However, heterogeneity is difficult to fully characterize for multiple reasons: (i) single-molecule approaches are needed to avoid information lost by ensemble-level averaging, (ii) sufficient statistics must be gathered on both a per-molecule and per-population level, and (iii) a suitable analysis framework is required to make sense of a potentially limited number of intrinsically noisy measurements. Here, we introduce an approach that overcomes these difficulties by combining three techniques: a DNA nanoswitch construct to repeatedly interrogate the same molecule, a benchtop centrifuge force microscope (CFM) to obtain thousands of statistics in a highly parallel manner, and a Bayesian nonparametric (BNP) inference method to resolve separate subpopulations with distinct kinetics. We apply this approach to characterize commercially available antibodies and find that polyclonal antibody from rabbit serum is well-modeled by a mixture of three subpopulations. Our results show how combining a spatially and temporally multiplexed nanoswitch-CFM assay with BNP analysis can help resolve complex biomolecular interactions in heterogeneous samples.
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Affiliation(s)
- Yi Luo
- Program
in Cellular and Molecular Medicine, Boston
Children’s Hospital, Boston, Massachusetts 02115, United States,Wyss
Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States,Department
of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Jeffrey Chang
- Department
of Physics, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Darren Yang
- Program
in Cellular and Molecular Medicine, Boston
Children’s Hospital, Boston, Massachusetts 02115, United States,Wyss
Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States,Department
of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - J. Shepard Bryan
- Department
of Physics, Arizona State University, Tempe, Arizona 85287, United States,Center
for
Biological Physics, Arizona State University, Tempe, Arizona 85287, United States
| | - Molly MacIsaac
- Program
in Cellular and Molecular Medicine, Boston
Children’s Hospital, Boston, Massachusetts 02115, United States,Wyss
Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States,Department
of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Steve Pressé
- Department
of Physics, Arizona State University, Tempe, Arizona 85287, United States,Center
for
Biological Physics, Arizona State University, Tempe, Arizona 85287, United States,School
of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
| | - Wesley P. Wong
- Program
in Cellular and Molecular Medicine, Boston
Children’s Hospital, Boston, Massachusetts 02115, United States,Wyss
Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States,Department
of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, United States,
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9
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Stachiv I, Kuo CY, Li W. Protein adsorption by nanomechanical mass spectrometry: Beyond the real-time molecular weighting. Front Mol Biosci 2023; 9:1058441. [PMID: 36685281 PMCID: PMC9849248 DOI: 10.3389/fmolb.2022.1058441] [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: 09/30/2022] [Accepted: 12/14/2022] [Indexed: 01/06/2023] Open
Abstract
During past decades, enormous progress in understanding the mechanisms of the intermolecular interactions between the protein and surface at the single-molecule level has been achieved. These advances could only be possible by the ongoing development of highly sophisticated experimental methods such as atomic force microscopy, optical microscopy, surface plasmon resonance, ellipsometry, quartz crystal microbalance, conventional mass spectrometry, and, more recently, the nanomechanical systems. Here, we highlight the main findings of recent studies on the label-free single-molecule (protein) detection by nanomechanical systems including those focusing on the protein adsorption on various substrate surfaces. Since the nanomechanical techniques are capable of detecting and manipulating proteins even at the single-molecule level, therefore, they are expected to open a new way of studying the dynamics of protein functions. It is noteworthy that, in contrast to other experimental methods, where only given protein properties like molecular weight or protein stiffness can be determined, the nanomechanical systems enable a real-time measurement of the multiple protein properties (e.g., mass, stiffness, and/or generated surface stress), making them suitable for the study of protein adsorption mechanisms. Moreover, we also discuss the possible future trends in label-free detection and analysis of dynamics of protein complexes with these nanomechanical systems.
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Affiliation(s)
- Ivo Stachiv
- Department of Functional Materials, Institute of Physics, Czech Academy of Sciences, Prague, Czechia,*Correspondence: Ivo Stachiv,
| | - Chih-Yun Kuo
- Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine and General University Hospital in Prague, Charles University, Prague, Czechia
| | - Wei Li
- Department of Functional Materials, Institute of Physics, Czech Academy of Sciences, Prague, Czechia
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10
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Griffith JE, Chen Y, Liu Q, Wang Q, Richards JJ, Tullman-Ercek D, Shull KR, Wang M. Quantitative high-throughput measurement of bulk mechanical properties using commonly available equipment. MATERIALS HORIZONS 2023; 10:97-106. [PMID: 36305296 DOI: 10.1039/d2mh01064j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Machine learning approaches have introduced an urgent need for large datasets of materials properties. However, for mechanical properties, current high-throughput measurement methods typically require complex robotic instrumentation, with enormous capital costs that are inaccessible to most experimentalists. A quantitative high-throughput method using only common lab equipment and consumables with simple fabrication steps is long desired. Here, we present such a technique that can measure bulk mechanical properties in soft materials with a common laboratory centrifuge, multiwell plates, and microparticles. By applying a homogeneous force on the particles embedded inside samples in the multiwell plate using centrifugation, we show that our technique measures the fracture stress of gels with similar accuracy to a rheometer. However, our method has a throughput on the order of 103 samples per run and is generalizable to virtually all soft material systems. We hope that our method can expedite materials discovery and potentially inspire the future development of additional high-throughput characterization methods.
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Affiliation(s)
- Justin E Griffith
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | - Yusu Chen
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | - Qingsong Liu
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | - Qifeng Wang
- Department of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Jeffrey J Richards
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | - Danielle Tullman-Ercek
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
| | - Kenneth R Shull
- Department of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - Muzhou Wang
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, USA.
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11
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Pokhrel P, Hu C, Mao H. Ensemble Force Spectroscopy by Shear Forces. J Vis Exp 2022:10.3791/63741. [PMID: 35969056 PMCID: PMC10373445 DOI: 10.3791/63741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023] Open
Abstract
Single-molecule techniques based on fluorescence and mechanochemical principles provide superior sensitivity in biological sensing. However, due to the lack of high throughput capabilities, the application of these techniques is limited in biophysics. Ensemble force spectroscopy (EFS) has demonstrated high throughput in the investigation of a massive set of molecular structures by converting mechanochemical studies of individual molecules into those of molecular ensembles. In this protocol, the DNA secondary structures (i-motifs) were unfolded in the shear flow between the rotor and stator of a homogenizer tip at shear rates up to 77796/s. The effects of flow rates and molecular sizes on the shear forces experienced by the i-motif were demonstrated. The EFS technique also revealed the binding affinity between DNA i-motifs and ligands. Furthermore, we have demonstrated a click chemistry reaction that can be actuated by shear force (i.e., mechano-click chemistry). These results establish the effectiveness of using shear force to control the conformation of molecular structures.
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Affiliation(s)
- Pravin Pokhrel
- Department of Chemistry & Biochemistry, Kent State University
| | - Changpeng Hu
- Department of Chemistry & Biochemistry, Kent State University
| | - Hanbin Mao
- Department of Chemistry & Biochemistry, Kent State University;
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12
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Abstract
In the dynamic environment of the airways, where SARS-CoV-2 infections are initiated by binding to human host receptor ACE2, mechanical stability of the viral attachment is a crucial fitness advantage. Using single-molecule force spectroscopy techniques, we mimic the effect of coughing and sneezing, thereby testing the force stability of SARS-CoV-2 RBD:ACE2 interaction under physiological conditions. Our results reveal a higher force stability of SARS-CoV-2 binding to ACE2 compared to SARS-CoV-1, causing a possible fitness advantage. Our assay is sensitive to blocking agents preventing RBD:ACE2 bond formation. It will thus provide a powerful approach to investigate the modes of action of neutralizing antibodies and other agents designed to block RBD binding to ACE2 that are currently developed as potential COVID-19 therapeutics. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections are initiated by attachment of the receptor-binding domain (RBD) on the viral Spike protein to angiotensin-converting enzyme-2 (ACE2) on human host cells. This critical first step occurs in dynamic environments, where external forces act on the binding partners and avidity effects play an important role, creating an urgent need for assays that can quantitate SARS-CoV-2 interactions with ACE2 under mechanical load. Here, we introduce a tethered ligand assay that comprises the RBD and the ACE2 ectodomain joined by a flexible peptide linker. Using magnetic tweezers and atomic force spectroscopy as highly complementary single-molecule force spectroscopy techniques, we investigate the RBD:ACE2 interaction over the whole physiologically relevant force range. We combine the experimental results with steered molecular dynamics simulations and observe and assign fully consistent unbinding and unfolding events across the three techniques, enabling us to establish ACE2 unfolding as a molecular fingerprint. Measuring at forces of 2 to 5 pN, we quantify the force dependence and kinetics of the RBD:ACE2 bond in equilibrium. We show that the SARS-CoV-2 RBD:ACE2 interaction has higher mechanical stability, larger binding free energy, and a lower dissociation rate compared to SARS-CoV-1, which helps to rationalize the different infection patterns of the two viruses. By studying how free ACE2 outcompetes tethered ACE2, we show that our assay is sensitive to prevention of bond formation by external binders. We expect our results to provide a way to investigate the roles of viral mutations and blocking agents for targeted pharmaceutical intervention.
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13
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Shrestha P, Yang D, Tomov TE, MacDonald JI, Ward A, Bergal HT, Krieg E, Cabi S, Luo Y, Nathwani B, Johnson-Buck A, Shih WM, Wong WP. Single-molecule mechanical fingerprinting with DNA nanoswitch calipers. NATURE NANOTECHNOLOGY 2021; 16:1362-1370. [PMID: 34675411 PMCID: PMC8678201 DOI: 10.1038/s41565-021-00979-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 08/16/2021] [Indexed: 05/31/2023]
Abstract
Decoding the identity of biomolecules from trace samples is a longstanding goal in the field of biotechnology. Advances in DNA analysis have substantially affected clinical practice and basic research, but corresponding developments for proteins face challenges due to their relative complexity and our inability to amplify them. Despite progress in methods such as mass spectrometry and mass cytometry, single-molecule protein identification remains a highly challenging objective. Towards this end, we combine DNA nanotechnology with single-molecule force spectroscopy to create a mechanically reconfigurable DNA nanoswitch caliper capable of measuring multiple coordinates on single biomolecules with atomic resolution. Using optical tweezers, we demonstrate absolute distance measurements with ångström-level precision for both DNA and peptides, and using multiplexed magnetic tweezers, we demonstrate quantification of relative abundance in mixed samples. Measuring distances between DNA-labelled residues, we perform single-molecule fingerprinting of synthetic and natural peptides, and show discrimination, within a heterogeneous population, between different posttranslational modifications. DNA nanoswitch calipers are a powerful and accessible tool for characterizing distances within nanoscale complexes that will enable new applications in fields such as single-molecule proteomics.
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Affiliation(s)
- Prakash Shrestha
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Darren Yang
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Toma E Tomov
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - James I MacDonald
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Andrew Ward
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Hans T Bergal
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Biophysics Program, Harvard University, Cambridge, MA, USA
| | - Elisha Krieg
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Serkan Cabi
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Yi Luo
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Bhavik Nathwani
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Alexander Johnson-Buck
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Biophysics Program, Harvard University, Cambridge, MA, USA
| | - William M Shih
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA.
| | - Wesley P Wong
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA.
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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14
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Su H, Brockman JM, Duan Y, Sen N, Chhabra H, Bazrafshan A, Blanchard AT, Meyer T, Andrews B, Doye JPK, Ke Y, Dyer RB, Salaita K. Massively Parallelized Molecular Force Manipulation with On-Demand Thermal and Optical Control. J Am Chem Soc 2021; 143:19466-19473. [PMID: 34762807 DOI: 10.1021/jacs.1c08796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In single-molecule force spectroscopy (SMFS), a tethered molecule is stretched using a specialized instrument to study how macromolecules extend under force. One problem in SMFS is the serial and slow nature of the measurements, performed one molecule at a time. To address this long-standing challenge, we report on the origami polymer force clamp (OPFC) which enables parallelized manipulation of the mechanical forces experienced by molecules without the need for dedicated SMFS instruments or surface tethering. The OPFC positions target molecules between a rigid nanoscale DNA origami beam and a responsive polymer particle that shrinks on demand. As a proof-of-concept, we record the steady state and time-resolved mechanical unfolding dynamics of DNA hairpins using the fluorescence signal from ensembles of molecules and confirm our conclusion using modeling.
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Affiliation(s)
- Hanquan Su
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Joshua M Brockman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Yuxin Duan
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Navoneel Sen
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Hemani Chhabra
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Alisina Bazrafshan
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Aaron T Blanchard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Travis Meyer
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - Brooke Andrews
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Jonathan P K Doye
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Yonggang Ke
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, United States
| | - R Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia 30322, United States
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15
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Hu C, Jonchhe S, Pokhrel P, Karna D, Mao H. Mechanical unfolding of ensemble biomolecular structures by shear force. Chem Sci 2021; 12:10159-10164. [PMID: 34377405 PMCID: PMC8336480 DOI: 10.1039/d1sc02257a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/11/2021] [Indexed: 01/09/2023] Open
Abstract
Mechanical unfolding of biomolecular structures has been exclusively performed at the single-molecule level by single-molecule force spectroscopy (SMFS) techniques. Here we transformed sophisticated mechanical investigations on individual molecules into a simple platform suitable for molecular ensembles. By using shear flow inside a homogenizer tip, DNA secondary structures such as i-motifs are unfolded by shear force up to 50 pN at a 77 796 s-1 shear rate. We found that the larger the molecules, the higher the exerted shear forces. This shear force approach revealed affinity between ligands and i-motif structures. It also demonstrated a mechano-click reaction in which a Cu(i) catalyzed azide-alkyne cycloaddition was modulated by shear force. We anticipate that this ensemble force spectroscopy method can investigate intra- and inter-molecular interactions with the throughput, accuracy, and robustness unparalleled to those of SMFS methods.
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Affiliation(s)
- Changpeng Hu
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Sagun Jonchhe
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Pravin Pokhrel
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Deepak Karna
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
| | - Hanbin Mao
- Department of Chemistry & Biochemistry and School of Biomedical Sciences, Advanced Materials and Liquid Crystal Institute, Kent State University Kent OH 44242 USA
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16
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Alegre-Cebollada J. Protein nanomechanics in biological context. Biophys Rev 2021; 13:435-454. [PMID: 34466164 PMCID: PMC8355295 DOI: 10.1007/s12551-021-00822-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 07/05/2021] [Indexed: 12/20/2022] Open
Abstract
How proteins respond to pulling forces, or protein nanomechanics, is a key contributor to the form and function of biological systems. Indeed, the conventional view that proteins are able to diffuse in solution does not apply to the many polypeptides that are anchored to rigid supramolecular structures. These tethered proteins typically have important mechanical roles that enable cells to generate, sense, and transduce mechanical forces. To fully comprehend the interplay between mechanical forces and biology, we must understand how protein nanomechanics emerge in living matter. This endeavor is definitely challenging and only recently has it started to appear tractable. Here, I introduce the main in vitro single-molecule biophysics methods that have been instrumental to investigate protein nanomechanics over the last 2 decades. Then, I present the contemporary view on how mechanical force shapes the free energy of tethered proteins, as well as the effect of biological factors such as post-translational modifications and mutations. To illustrate the contribution of protein nanomechanics to biological function, I review current knowledge on the mechanobiology of selected muscle and cell adhesion proteins including titin, talin, and bacterial pilins. Finally, I discuss emerging methods to modulate protein nanomechanics in living matter, for instance by inducing specific mechanical loss-of-function (mLOF). By interrogating biological systems in a causative manner, these new tools can contribute to further place protein nanomechanics in a biological context.
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17
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Chen Y, Wang Q, Mills CE, Kann JG, Shull KR, Tullman-Ercek D, Wang M. High-Throughput Screening Test for Adhesion in Soft Materials Using Centrifugation. ACS CENTRAL SCIENCE 2021; 7:1135-1143. [PMID: 34345666 PMCID: PMC8323114 DOI: 10.1021/acscentsci.1c00414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Indexed: 05/24/2023]
Abstract
High-throughput screening of mechanical properties can transform materials science research by both aiding in materials discovery and developing predictive models. However, only a few such assays have been reported, requiring custom or expensive equipment, while the mounting demand for enormous data sets of materials properties for predictive models is unfulfilled by the current characterization throughput. We address this problem by developing a high-throughput colorimetric adhesion screening method using a common laboratory centrifuge, multiwell plates, and microparticles. The technique uses centrifugation to apply a homogeneous mechanical detachment force across individual formulations in a multiwell plate. We also develop a high-throughput sample deposition method to prepare films with uniform thickness in each well, minimizing well-to-well variability. After establishing excellent agreement with the well-known probe tack adhesion test, we demonstrate the consistency of our method by performing the test on a multiwell plate with two different formulations in an easily discernible pattern. The throughput is limited only by the number of wells in the plates, easily reaching 103 samples/run. With its simplicity, low cost, and large dynamic range, this high-throughput method has the potential to change the landscape of adhesive material characterization.
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Affiliation(s)
- Yusu Chen
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208-3120, United States
| | - Qifeng Wang
- Department
of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208-3108, United States
| | - Carolyn E. Mills
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208-3120, United States
| | - Johanna G. Kann
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208-3120, United States
| | - Kenneth R. Shull
- Department
of Materials Science & Engineering, Northwestern University, Evanston, Illinois 60208-3108, United States
| | - Danielle Tullman-Ercek
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208-3120, United States
| | - Muzhou Wang
- Department
of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208-3120, United States
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18
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Zheng Y, Han MKL, Zhao R, Blass J, Zhang J, Zhou DW, Colard-Itté JR, Dattler D, Çolak A, Hoth M, García AJ, Qu B, Bennewitz R, Giuseppone N, Del Campo A. Optoregulated force application to cellular receptors using molecular motors. Nat Commun 2021; 12:3580. [PMID: 34117256 PMCID: PMC8196032 DOI: 10.1038/s41467-021-23815-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 05/13/2021] [Indexed: 01/16/2023] Open
Abstract
Progress in our understanding of mechanotransduction events requires noninvasive methods for the manipulation of forces at molecular scale in physiological environments. Inspired by cellular mechanisms for force application (i.e. motor proteins pulling on cytoskeletal fibers), we present a unique molecular machine that can apply forces at cell-matrix and cell-cell junctions using light as an energy source. The key actuator is a light-driven rotatory molecular motor linked to polymer chains, which is intercalated between a membrane receptor and an engineered biointerface. The light-driven actuation of the molecular motor is converted in mechanical twisting of the entangled polymer chains, which will in turn effectively “pull” on engaged cell membrane receptors (e.g., integrins, T cell receptors) within the illuminated area. Applied forces have physiologically-relevant magnitude and occur at time scales within the relevant ranges for mechanotransduction at cell-friendly exposure conditions, as demonstrated in force-dependent focal adhesion maturation and T cell activation experiments. Our results reveal the potential of nanomotors for the manipulation of living cells at the molecular scale and demonstrate a functionality which at the moment cannot be achieved by other technologies for force application. Molecular scale force application in physiological environments is important for studying mechanotransduction. Here, the authors use a molecular machine to apply forces at cell-matrix and cell-cell junctions using light to trigger twisting actuation which then pulls on cell membrane receptors.
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Affiliation(s)
- Yijun Zheng
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany
| | | | - Renping Zhao
- Biophysics, CIPMM, School of Medicine, Saarland University, Homburg, Germany
| | - Johanna Blass
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Jingnan Zhang
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Dennis W Zhou
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jean-Rémy Colard-Itté
- SAMS Research Group, Institut Charles Sadron, University of Strasbourg - CNRS, Strasbourg, France
| | - Damien Dattler
- SAMS Research Group, Institut Charles Sadron, University of Strasbourg - CNRS, Strasbourg, France
| | - Arzu Çolak
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Markus Hoth
- Biophysics, CIPMM, School of Medicine, Saarland University, Homburg, Germany
| | - Andrés J García
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.,Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
| | - Bin Qu
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany.,Biophysics, CIPMM, School of Medicine, Saarland University, Homburg, Germany
| | - Roland Bennewitz
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany.,Saarland University, Physics Department, Saarbrücken, Germany
| | - Nicolas Giuseppone
- SAMS Research Group, Institut Charles Sadron, University of Strasbourg - CNRS, Strasbourg, France
| | - Aránzazu Del Campo
- INM - Leibniz Institute for New Materials, Saarbrücken, Germany. .,Saarland University, Chemistry Department, Saarbrücken, Germany.
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19
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Penth M, Schellnhuber K, Bennewitz R, Blass J. Nanomechanics of self-assembled DNA building blocks. NANOSCALE 2021; 13:9371-9380. [PMID: 33999986 DOI: 10.1039/d0nr06865a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
DNA has become a powerful platform to design functional nanodevices. DNA nanodevices are often composed of self-assembled DNA building blocks that differ significantly from the structure of native DNA. In this study, we present Flow Force Microscopy as a massively parallel approach to study the nanomechanics of DNA self-assemblies on the single-molecular level. The high-throughput experiments performed in a simple microfluidic channel enable statistically meaningful studies with nanometer scale precision in a time frame of several minutes. A surprisingly high flexibility was observed for a typical construct used in DNA origami, reflected in a persistence length of 10.2 nm, a factor of five smaller than for native DNA. The enhanced flexibility is attributed to the discontinuous backbone of DNA self-assemblies that facilitate base pair opening by thermal fluctuations at the end of hybridized oligomers. We believe that the results will contribute to the fundamental understanding of DNA nanomechanics and help to improve the design of DNA nanodevices with applications in biological analysis and clinical research.
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Affiliation(s)
- Michael Penth
- INM - Leibniz Institute for New Materials, Campus D22, 66123 Saarbrücken, Germany. and Physics Department, Campus D22, 66123 Saarbrücken, Germany
| | - Kordula Schellnhuber
- INM - Leibniz Institute for New Materials, Campus D22, 66123 Saarbrücken, Germany. and Physics Department, Campus D22, 66123 Saarbrücken, Germany
| | - Roland Bennewitz
- INM - Leibniz Institute for New Materials, Campus D22, 66123 Saarbrücken, Germany. and Physics Department, Campus D22, 66123 Saarbrücken, Germany
| | - Johanna Blass
- INM - Leibniz Institute for New Materials, Campus D22, 66123 Saarbrücken, Germany.
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20
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Lin Z, Gao X, Li S, Hu C. Learning-based event locating for single-molecule force spectroscopy. Biochem Biophys Res Commun 2021; 556:59-64. [PMID: 33839415 DOI: 10.1016/j.bbrc.2021.03.159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/29/2021] [Indexed: 12/31/2022]
Abstract
Acquiring events massively from single-molecule force spectroscopy (SMFS) experiments, which is crucial for revealing important biophysical information, is usually not straightforward. A significant amount of human labor is usually required to identify events in the measured force spectrum during measuring or before performing further data analysis. This prevents the experiment from being done in a fully-automated manner or scaling with the throughput of the measuring setup. In this work, we attempt to tackle this problem with a deep learning approach. A deep neural network model is developed to infer the occurrence of the events using the data stream from the measuring setup. We demonstrated that the proposed method could achieve high accuracy with force spectrums of a variety of samples from both optical tweezers and AFMs by learning from user-given samples instead of complicated manual algorithm designing or parameter tuning. Furthermore, we found that the trained model can be used to perform event detection on datasets measured from a different optical tweezer setup, showing the potential of being leveraged in more complex deep learning schemes.
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Affiliation(s)
- Zuzeng Lin
- Key Lab of Precision Measuring Technology and Instrument, Tianjin University, China
| | - Xiaoqing Gao
- Key Lab of Precision Measuring Technology and Instrument, Tianjin University, China
| | - Shuai Li
- Key Lab of Precision Measuring Technology and Instrument, Tianjin University, China
| | - Chunguang Hu
- Key Lab of Precision Measuring Technology and Instrument, Tianjin University, China.
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21
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Abstract
Selective and sensitive detection of nucleic acid biomarkers is of great significance in early-stage diagnosis and targeted therapy. Therefore, the development of diagnostic methods capable of detecting diseases at the molecular level in biological fluids is vital to the emerging revolution in the early diagnosis of diseases. However, the vast majority of the currently available ultrasensitive detection strategies involve either target/signal amplification or involve complex designs. Here, using a p53 tumor suppressor gene whose mutation has been implicated in more than 50% of human cancers, we show a background-free ultrasensitive detection of this gene on a simple platform. The sensor exhibits a relatively static mid-FRET state in the absence of a target that can be attributed to the time-averaged fluorescence intensity of fast transitions among multiple states, but it undergoes continuous dynamic switching between a low- and a high-FRET state in the presence of a target, allowing a high-confidence detection. In addition to its simple design, the sensor has a detection limit down to low femtomolar (fM) concentration without the need for target amplification. We also show that this sensor is highly effective in discriminating against single-nucleotide polymorphisms (SNPs). Given the generic hybridization-based detection platform, the sensing strategy developed here can be used to detect a wide range of nucleic acid sequences enabling early diagnosis of diseases and screening genetic disorders.
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Affiliation(s)
- Anoja Megalathan
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Kalani M Wijesinghe
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
| | - Soma Dhakal
- Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States
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22
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Chandrasekaran AR, Dey BK, Halvorsen K. How to Perform miRacles: A Step-by-Step microRNA Detection Protocol Using DNA Nanoswitches. ACTA ACUST UNITED AC 2021; 130:e114. [PMID: 32048806 DOI: 10.1002/cpmb.114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
MicroRNAs are short non-coding RNAs involved in post-transcriptional gene regulation, and are increasingly considered to be biomarkers for numerous biological processes and human diseases. Current techniques used for microRNA detection can be expensive and labor-intensive, and typically require amplification, labeling, or radioactive probes. In this protocol, we describe a DNA nanoswitch-based microRNA detection assay termed "miRacles": microRNA-activated conditional looping of engineered switches. This method uses conformationally responsive DNA nanoswitches that detect the presence of specific microRNAs with a simple and unambiguous gel-shift assay that can be performed on the benchtop. The assay is low cost, minimalistic, and capable of direct detection of specific microRNAs in unprocessed total RNA samples, with no enzymatic amplification, labeling, or special equipment. The protocol for detection of microRNAs in total RNA can be completed in as little as a few hours, making this assay a compelling alternative to qPCR and Northern blotting. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Preparation of DNA nanoswitches Basic Protocol 2: Detection of microRNAs from total RNA samples Support Protocol 1: Optional nanoswitch purification by PEG precipitation Support Protocol 2: Optional nanoswitch purification by liquid chromatography.
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Affiliation(s)
| | - Bijan K Dey
- The RNA Institute, University at Albany, State University of New York, Albany, New York.,Department of Biology, University at Albany, State University of New York, Albany, New York
| | - Ken Halvorsen
- The RNA Institute, University at Albany, State University of New York, Albany, New York
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23
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Abraham Punnoose J, Hayden A, Zhou L, Halvorsen K. Wi-Fi Live-Streaming Centrifuge Force Microscope for Benchtop Single-Molecule Experiments. Biophys J 2020; 119:2231-2239. [PMID: 33121943 PMCID: PMC7732769 DOI: 10.1016/j.bpj.2020.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 11/21/2022] Open
Abstract
The ability to apply controlled forces to individual molecules has been revolutionary in shaping our understanding of biophysics in areas as diverse as dynamic bond strength, biological motor operation, and DNA replication. However, the methodology to perform single-molecule experiments remains relatively inaccessible because of cost and complexity. In 2010, we introduced the centrifuge force microscope (CFM) as a platform for accessible and high-throughput single-molecule experimentation. The CFM consists of a rotating microscope with which prescribed centrifugal forces can be applied to microsphere-tethered biomolecules. In this work, we develop and demonstrate a next-generation Wi-Fi CFM that offers unprecedented ease of use and flexibility in design. The modular CFM unit fits within a standard benchtop centrifuge and connects by Wi-Fi to an external computer for live control and streaming at near gigabit speeds. The use of commercial wireless hardware allows for flexibility in programming and provides a streamlined upgrade path as Wi-Fi technology advances. To facilitate ease of use, detailed build and setup instructions, as well as LabVIEW-based control software and MATLAB-based analysis software, are provided. We demonstrate the instrument’s performance by analysis of force-dependent dissociation of short DNA duplexes of 7, 8, and 9 bp. We showcase the sensitivity of the approach by resolving distinct dissociation kinetic rates for a 7 bp duplex in which one G-C basepair is mutated to an A-T basepair.
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Affiliation(s)
| | | | - Lifeng Zhou
- RNA Institute, SUNY at Albany, Albany, New York
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24
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Agarwal R, Duderstadt KE. Multiplex flow magnetic tweezers reveal rare enzymatic events with single molecule precision. Nat Commun 2020; 11:4714. [PMID: 32948754 PMCID: PMC7501243 DOI: 10.1038/s41467-020-18456-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023] Open
Abstract
The application of forces and torques on the single molecule level has transformed our understanding of the dynamic properties of biomolecules, but rare intermediates have remained difficult to characterize due to limited throughput. Here, we describe a method that provides a 100-fold improvement in the throughput of force spectroscopy measurements with topological control, which enables routine imaging of 50,000 single molecules and a 100 million reaction cycles in parallel. This improvement enables detection of rare events in the life cycle of the cell. As a demonstration, we characterize the supercoiling dynamics and drug-induced DNA break intermediates of topoisomerases. To rapidly quantify distinct classes of dynamic behaviors and rare events, we developed a software platform with an automated feature classification pipeline. The method and software can be readily adapted for studies of a broad range of complex, multistep enzymatic pathways in which rare intermediates have escaped classification due to limited throughput.
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Affiliation(s)
- Rohit Agarwal
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany
- Physik Department, Technische Universität München, Garching, Germany
| | - Karl E Duderstadt
- Structure and Dynamics of Molecular Machines, Max Planck Institute of Biochemistry, Martinsried, Germany.
- Physik Department, Technische Universität München, Garching, Germany.
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25
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Chandrasekaran AR, Trivedi R, Halvorsen K. Ribonuclease-Responsive DNA Nanoswitches. CELL REPORTS. PHYSICAL SCIENCE 2020; 1:100117. [PMID: 32803173 PMCID: PMC7425801 DOI: 10.1016/j.xcrp.2020.100117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
DNA has been used in the construction of dynamic DNA devices that can reconfigure in the presence of external stimuli. These nanodevices have found uses in fields ranging from biomedical to materials science applications. Here, we report a DNA nanoswitch that can be reconfigured using ribonucleases (RNases) and explore two applications: biosensing and molecular computing. For biosensing, we show the detection of RNase H and other RNases in relevant biological fluids and temperatures, as well as inhibition by the known enzyme inhibitor kanamycin. For molecular computing, we show that RNases can be used to enable erasing, write protection, and erase-rewrite functionality for information-encoding DNA nanoswitches. The simplistic mix-and-read nature of the ribonuclease-activated DNA nanoswitches could facilitate their use in assays for identifying RNase contamination in biological samples or for the screening and characterization of RNase inhibitors.
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Affiliation(s)
- Arun Richard Chandrasekaran
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
- Twitter: @arunrichardc
| | - Ruju Trivedi
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Ken Halvorsen
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
- Twitter: @HalvorsenLab
- Lead Contact
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26
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Yang B, Liu Z, Liu H, Nash MA. Next Generation Methods for Single-Molecule Force Spectroscopy on Polyproteins and Receptor-Ligand Complexes. Front Mol Biosci 2020; 7:85. [PMID: 32509800 PMCID: PMC7248566 DOI: 10.3389/fmolb.2020.00085] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/16/2020] [Indexed: 12/31/2022] Open
Abstract
Single-molecule force spectroscopy with the atomic force microscope provides molecular level insights into protein function, allowing researchers to reconstruct energy landscapes and understand functional mechanisms in biology. With steadily advancing methods, this technique has greatly accelerated our understanding of force transduction, mechanical deformation, and mechanostability within single- and multi-domain polyproteins, and receptor-ligand complexes. In this focused review, we summarize the state of the art in terms of methodology and highlight recent methodological improvements for AFM-SMFS experiments, including developments in surface chemistry, considerations for protein engineering, as well as theory and algorithms for data analysis. We hope that by condensing and disseminating these methods, they can assist the community in improving data yield, reliability, and throughput and thereby enhance the information that researchers can extract from such experiments. These leading edge methods for AFM-SMFS will serve as a groundwork for researchers cognizant of its current limitations who seek to improve the technique in the future for in-depth studies of molecular biomechanics.
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Affiliation(s)
- Byeongseon Yang
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Zhaowei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Haipei Liu
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Michael A. Nash
- Department of Chemistry, University of Basel, Basel, Switzerland
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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27
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Wilson BD, Soh HT. Re-Evaluating the Conventional Wisdom about Binding Assays. Trends Biochem Sci 2020; 45:639-649. [PMID: 32402748 DOI: 10.1016/j.tibs.2020.04.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/30/2020] [Accepted: 04/14/2020] [Indexed: 12/19/2022]
Abstract
Analytical technologies based on binding assays have evolved substantially since their inception nearly 60 years ago, but our conceptual understanding of molecular recognition has not kept pace. Contemporary technologies, such as single-molecule and digital measurements, have challenged, or even rendered obsolete, core concepts behind conventional binding assay design. Here, we explore the fundamental principles underlying molecular recognition systems, which we consider in terms of signals generated through concentration-dependent shifts in equilibrium. We challenge certain orthodoxies related to binding-based detection assays, including the primary importance of a low dissociation constant (KD) and the extent to which this parameter constrains dynamic range and limit of detection. Lastly, we identify key principles for designing binding assays that are optimally suited for a given detection application.
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Affiliation(s)
- Brandon D Wilson
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - H Tom Soh
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA; Department of Radiology, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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28
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White DS, Goldschen-Ohm MP, Goldsmith RH, Chanda B. Top-down machine learning approach for high-throughput single-molecule analysis. eLife 2020; 9:e53357. [PMID: 32267232 PMCID: PMC7205464 DOI: 10.7554/elife.53357] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 04/08/2020] [Indexed: 12/16/2022] Open
Abstract
Single-molecule approaches provide enormous insight into the dynamics of biomolecules, but adequately sampling distributions of states and events often requires extensive sampling. Although emerging experimental techniques can generate such large datasets, existing analysis tools are not suitable to process the large volume of data obtained in high-throughput paradigms. Here, we present a new analysis platform (DISC) that accelerates unsupervised analysis of single-molecule trajectories. By merging model-free statistical learning with the Viterbi algorithm, DISC idealizes single-molecule trajectories up to three orders of magnitude faster with improved accuracy compared to other commonly used algorithms. Further, we demonstrate the utility of DISC algorithm to probe cooperativity between multiple binding events in the cyclic nucleotide binding domains of HCN pacemaker channel. Given the flexible and efficient nature of DISC, we anticipate it will be a powerful tool for unsupervised processing of high-throughput data across a range of single-molecule experiments.
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Affiliation(s)
- David S White
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Department of Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | | | - Randall H Goldsmith
- Department of Chemistry, University of Wisconsin-MadisonMadisonUnited States
| | - Baron Chanda
- Department of Neuroscience, University of Wisconsin-MadisonMadisonUnited States
- Department of Biomolecular Chemistry University of Wisconsin-MadisonMadisonUnited States
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29
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Deng Y, Ma L, Han Q, Yu C, Johnson-Buck A, Su X. DNA-Templated Timer Probes for Multiplexed Sensing. NANO LETTERS 2020; 20:2688-2694. [PMID: 32119561 DOI: 10.1021/acs.nanolett.0c00313] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Simultaneous analysis based on encoded fluorophores suffers from potential crosstalk between fluorophores and the limited number of colors that can be practically resolved. Inspired by nontrivial temporal patterns in living organisms, we developed a DNA-templated probe by utilizing DNA polymerase (DNAP) for multiplexed detection of nucleic acids. These probes use differential delay times of signaling by a DNAP-mediated extension to distinguish different targets, which serve as the primers. Taking advantage of the high processivity and the controllable kinetics of DNAP, we find that multiplexed detection can be achieved in homogeneous solution using a single fluorophore. As a proof of concept, we developed assays for genomic DNA from four different bacteria. In addition, we designed and implemented probes to undergo a single oscillation in signal as an alternative way for multiplexing. We anticipate this approach will find broad applications not only in sensing but also in synthetic DNA nanosystems.
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Affiliation(s)
- Yingnan Deng
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Liang Ma
- Clinical Laboratory, China-Japan Friendship Hospital, Beijing 100029, China
| | - Qianqian Han
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Changyuan Yu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Alexander Johnson-Buck
- Department of Internal Medicine, Division of Hematology/Oncology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Xin Su
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
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30
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McCauley MJ, Rouzina I, Williams MC. Specific Nucleic Acid Chaperone Activity of HIV-1 Nucleocapsid Protein Deduced from Hairpin Unfolding. Methods Mol Biol 2020; 2106:59-88. [PMID: 31889251 DOI: 10.1007/978-1-0716-0231-7_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RNA and DNA hairpin formation and disruption play key regulatory roles in a variety of cellular processes. The 59-nucleotide transactivation response (TAR) RNA hairpin facilitates the production of full-length transcripts of the HIV-1 genome. Yet the stability of this long, irregular hairpin becomes a liability during reverse transcription as 24 base pairs must be disrupted for strand transfer. Retroviral nucleocapsid (NC) proteins serve as nucleic acid chaperones that have been shown to both destabilize the TAR hairpin and facilitate strand annealing with its complementary DNA sequence. Yet it has remained difficult to elucidate the way NC targets and dramatically destabilizes this hairpin while only weakly affecting the annealed product. In this work, we used optical tweezers to measure the stability of TAR and found that adding NC destabilized the hairpin and simultaneously caused a distinct change in both the height and location of the energy barrier. This data was matched to an energy landscape predicted from a simple theory of definite base pair destabilization. Comparisons revealed the specific binding sites found by NC along the irregular TAR hairpin. Furthermore, specific binding explained both the unusual shift in the transition state and the much weaker effect on the annealed product. These experiments illustrate a general method of energy landscape transformation that exposes important physical insights.
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Affiliation(s)
| | - Ioulia Rouzina
- Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH, USA
| | - Mark C Williams
- Department of Physics, Northeastern University, Boston, MA, USA.
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31
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Ma G, Wan Z, Zhu H, Tao N. Roles of entropic and solvent damping forces in the dynamics of polymer tethered nanoparticles and implications for single molecule sensing. Chem Sci 2019; 11:1283-1289. [PMID: 33376589 PMCID: PMC7747464 DOI: 10.1039/c9sc05434k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/10/2019] [Indexed: 01/19/2023] Open
Abstract
Tethering a particle to a surface with a single molecule allows detection of the molecule and analysis of molecular conformations and interactions.
Tethering a particle to a surface with a single molecule allows detection of the molecule and analysis of molecular conformations and interactions. Understanding the dynamics of the system is critical to all applications. Here we present a plasmonic imaging study of two important forces that govern the dynamics. One is entropic force arising from the conformational change of the molecular tether, and the other is solvent damping on the particle and the molecule. We measure the response of the particle by driving it into oscillation with an alternating electric field. By varying the field frequency, we study the dynamics on different time scales. We also vary the type of the tether molecule (DNA and polyethylene glycol), size of the particle, and viscosity of the solvent, and describe the observations with a model. The study allows us to derive a single parameter to predict the relative importance of the entropic and damping forces. The findings provide insights into single molecule studies using not only tethered particles, but also other approaches, including force spectroscopy using atomic force microscopy and nanopores.
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Affiliation(s)
- Guangzhong Ma
- Biodesign Center for Biosensors and Bioelectronics , Arizona State University , Tempe , Arizona 85287 , USA .
| | - Zijian Wan
- Biodesign Center for Biosensors and Bioelectronics , Arizona State University , Tempe , Arizona 85287 , USA . .,School of Electrical, Computer and Energy Engineering , Arizona State University , Tempe , Arizona 85287 , USA
| | - Hao Zhu
- State Key Laboratory of Analytical Chemistry for Life Science , School of Chemistry and Chemical Engineering , Nanjing University , Nanjing 210023 , P. R. China
| | - Nongjian Tao
- Biodesign Center for Biosensors and Bioelectronics , Arizona State University , Tempe , Arizona 85287 , USA . .,School of Electrical, Computer and Energy Engineering , Arizona State University , Tempe , Arizona 85287 , USA
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32
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Zhao X, Guo S, Lu C, Chen J, Le S, Fu H, Yan J. Single-molecule manipulation quantification of site-specific DNA binding. Curr Opin Chem Biol 2019; 53:106-117. [DOI: 10.1016/j.cbpa.2019.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/24/2019] [Accepted: 08/24/2019] [Indexed: 10/25/2022]
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33
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Molecular scaffolds: when DNA becomes the hardware for single-molecule investigations. Curr Opin Chem Biol 2019; 53:192-203. [DOI: 10.1016/j.cbpa.2019.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 09/21/2019] [Accepted: 09/24/2019] [Indexed: 01/14/2023]
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34
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OTAKE M, UKITA Y. Dynamic Measurement Method for Bio-molecular Interactions by Using Centrifugal Force. ANAL SCI 2019; 35:1123-1127. [DOI: 10.2116/analsci.19p137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Mao OTAKE
- Faculty of Engineering, Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi
| | - Yoshiaki UKITA
- Faculty of Engineering, Integrated Graduate School of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi
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35
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Sample preparation method to improve the efficiency of high-throughput single-molecule force spectroscopy. BIOPHYSICS REPORTS 2019. [DOI: 10.1007/s41048-019-00097-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Abstract
Inefficient sample preparation methods hinder the performance of high-throughput single-molecule force spectroscopy (H-SMFS) for viscous damping among reactants and unstable linkage. Here, we demonstrated a sample preparation method for H-SMFS systems to achieve a higher ratio of effective target molecules per sample cell by gas-phase silanization and reactant hydrophobization. Digital holographic centrifugal force microscopy (DH-CFM) was used to verify its performance. The experimental result indicated that the DNA stretching success ratio was improved from 0.89% to 13.5%. This enhanced efficiency preparation method has potential application for force-based DNA stretching experiments and other modifying procedures.
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36
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Li N, Wang J, Ma K, Liang L, Mi L, Huang W, Ma X, Wang Z, Zheng W, Xu L, Chen JH, Yu Z. The dynamics of forming a triplex in an artificial telomere inferred by DNA mechanics. Nucleic Acids Res 2019; 47:e86. [PMID: 31114915 PMCID: PMC6735771 DOI: 10.1093/nar/gkz464] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 05/06/2019] [Accepted: 05/15/2019] [Indexed: 11/21/2022] Open
Abstract
A telomere carrying repetitive sequences ends with a single-stranded overhang. The G-rich overhang could fold back and bind in the major groove of its upstream duplex, forming an antiparallel triplex structure. The telomeric triplex has been proposed to function in protecting chromosome ends. However, we lack strategies to mechanically probe the dynamics of a telomeric triplex. Here, we show that the topological dynamics of a telomeric triplex involves 3' overhang binding at the ds/ssDNA junction inferred by DNA mechanics. Assisted by click chemistry and branched polymerase chain reaction, we developed a rescue-rope-strategy for mechanically manipulating an artificial telomeric DNA with a free end. Using single-molecule magnetic tweezers, we identified a rarely forming (5%) telomeric triplex which pauses at an intermediate state upon unzipping the Watson-Crick paired duplex. Our findings revealed that a mechanically stable triplex formed in a telomeric DNA can resist a force of 20 pN for a few seconds in a physiological buffer. We also demonstrated that the rescue-rope-strategy assisted mechanical manipulation can directly rupture the interactions between the third strand and its targeting duplex in a DNA triplex. Our single-molecule rescue-rope-strategy will serve as a general tool to investigate telomere dynamics and further develop triplex-based biotechnologies.
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Affiliation(s)
- Ning Li
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Junli Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Kangkang Ma
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Lin Liang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Lipei Mi
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Wei Huang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Xiaofeng Ma
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Zeyu Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Wei Zheng
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
| | - Linyan Xu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China
| | - Jun-Hu Chen
- National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Key Laboratory of Parasite and Vector Biology, Ministry of Health, Shanghai 200025, China
| | - Zhongbo Yu
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China
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Multiplexed protein force spectroscopy reveals equilibrium protein folding dynamics and the low-force response of von Willebrand factor. Proc Natl Acad Sci U S A 2019; 116:18798-18807. [PMID: 31462494 PMCID: PMC6754583 DOI: 10.1073/pnas.1901794116] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Single-molecule force spectroscopy has provided unprecedented insights into protein folding, force regulation, and function. So far, the field has relied primarily on atomic force microscope and optical tweezers assays that, while powerful, are limited in force resolution, throughput, and require feedback for constant force measurements. Here, we present a modular approach based on magnetic tweezers (MT) for highly multiplexed protein force spectroscopy. Our approach uses elastin-like polypeptide linkers for the specific attachment of proteins, requiring only short peptide tags on the protein of interest. The assay extends protein force spectroscopy into the low force (<1 pN) regime and enables parallel and ultra-stable measurements at constant forces. We present unfolding and refolding data for the small, single-domain protein ddFLN4, commonly used as a molecular fingerprint in force spectroscopy, and for the large, multidomain dimeric protein von Willebrand factor (VWF) that is critically involved in primary hemostasis. For both proteins, our measurements reveal exponential force dependencies of unfolding and refolding rates. We directly resolve the stabilization of the VWF A2 domain by Ca2+ and discover transitions in the VWF C domain stem at low forces that likely constitute the first steps of VWF's mechano-activation. Probing the force-dependent lifetime of biotin-streptavidin bonds, we find that monovalent streptavidin constructs with specific attachment geometry are significantly more force stable than commercial, multivalent streptavidin. We expect our modular approach to enable multiplexed force-spectroscopy measurements for a wide range of proteins, in particular in the physiologically relevant low-force regime.
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Abstract
![]()
Life is an emergent property of transient
interactions between
biomolecules and other organic and inorganic molecules that somehow
leads to harmony and order. Measurement and quantitation of these
biological interactions are of value to scientists and are major goals
of biochemistry, as affinities provide insight into biological processes.
In an organism, these interactions occur in the context of forces
and the need for a consideration of binding affinities in the context
of a changing mechanical landscape necessitates a new way to consider
the biochemistry of protein–protein interactions. In the past
few decades, the field of mechanobiology has exploded, as both the
appreciation of, and the technical advances required to facilitate
the study of, how forces impact biological processes have become evident.
The aim of this review is to introduce the concept of force dependence
of biomolecular interactions and the requirement to be able to measure
force-dependent binding constants. The focus of this discussion will
be on the mechanotransduction that occurs at the integrin-mediated
adhesions with the extracellular matrix and the major mechanosensors
talin and vinculin. However, the approaches that the cell uses to
sense and respond to forces can be applied to other systems, and this
therefore provides a general discussion of the force dependence of
biomolecule interactions.
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Affiliation(s)
- Yinan Wang
- Department of Physics , National University of Singapore , 117542 Singapore
| | - Jie Yan
- Department of Physics , National University of Singapore , 117542 Singapore.,Mechanobiology Institute , National University of Singapore , 117411 Singapore
| | - Benjamin T Goult
- School of Biosciences , University of Kent , Canterbury , Kent CT2 7NJ , U.K
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Shon MJ, Rah SH, Yoon TY. Submicrometer elasticity of double-stranded DNA revealed by precision force-extension measurements with magnetic tweezers. SCIENCE ADVANCES 2019; 5:eaav1697. [PMID: 31206015 PMCID: PMC6561745 DOI: 10.1126/sciadv.aav1697] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 05/03/2019] [Indexed: 05/07/2023]
Abstract
Submicrometer elasticity of double-stranded DNA (dsDNA) governs nanoscale bending of DNA segments and their interactions with proteins. Single-molecule force spectroscopy, including magnetic tweezers (MTs), is an important tool for studying DNA mechanics. However, its application to short DNAs under 1 μm is limited. We developed an MT-based method for precise force-extension measurements in the 100-nm regime that enables in situ correction of the error in DNA extension measurement, and normalizes the force variability across beads by exploiting DNA hairpins. The method reduces the lower limit of tractable dsDNA length down to 198 base pairs (bp) (67 nm), an order-of-magnitude improvement compared to conventional tweezing experiments. Applying this method and the finite worm-like chain model we observed an essentially constant persistence length across the chain lengths studied (198 bp to 10 kbp), which steeply depended on GC content and methylation. This finding suggests a potential sequence-dependent mechanism for short-DNA elasticity.
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Affiliation(s)
- Min Ju Shon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul 08826, South Korea
- Corresponding author. (T.-Y.Y.); (M.J.S.)
| | - Sang-Hyun Rah
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Tae-Young Yoon
- School of Biological Sciences and Institute for Molecular Biology and Genetics, Seoul National University, Seoul 08826, South Korea
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
- Corresponding author. (T.-Y.Y.); (M.J.S.)
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40
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Chandrasekaran AR, Abraham Punnoose J, Valsangkar V, Sheng J, Halvorsen K. Integration of a photocleavable element into DNA nanoswitches. Chem Commun (Camb) 2019; 55:6587-6590. [PMID: 31116197 DOI: 10.1039/c9cc03069g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Reconfigurable DNA nanostructures can be designed to respond to external stimuli such as nucleic acids, pH, small molecules and enzymes. In this study, we incorporated photocleavable linkers in DNA strands that trigger a conformational change in binary DNA nanoswitches. We demonstrate control of the output using UV light, with potential applications in biosensing and molecular computation.
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Affiliation(s)
| | - Jibin Abraham Punnoose
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA.
| | - Vibhav Valsangkar
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA. and Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jia Sheng
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA. and Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Ken Halvorsen
- The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA.
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41
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Drabek AA, Loparo JJ, Blacklow SC. A Flow-Extension Tethered Particle Motion Assay for Single-Molecule Proteolysis. Biochemistry 2019; 58:2509-2518. [PMID: 30946563 PMCID: PMC6607913 DOI: 10.1021/acs.biochem.9b00106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Regulated proteolysis of signaling proteins under mechanical tension enables cells to communicate with their environment in a variety of developmental and physiologic contexts. The role of force in inducing proteolytic sensitivity has been explored using magnetic tweezers at the single-molecule level with bead-tethered assays, but such efforts have been limited by challenges in ensuring that beads not be restrained by multiple tethers. Here, we describe a multiplexed assay for single-molecule proteolysis that overcomes the multiple-tether problem using a flow-extension strategy on a microscope equipped with magnetic tweezers. Particle tracking and computational sorting of flow-induced displacements allow assignment of tethered substrates to singly captured and multiply tethered bins, with the fraction of fully mobile, single-tether substrates depending inversely on the concentration of substrate loaded on the coverslip. Computational exclusion of multiple-tether beads enables robust assessment of on-target proteolysis by the highly specific tobacco etch virus protease and the more promiscuous metalloprotease ADAM17. This method should be generally applicable to a wide range of proteases and readily extensible to robust evaluation of proteolytic sensitivity as a function of applied magnetic force.
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Affiliation(s)
- Andrew A. Drabek
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Joseph J. Loparo
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Stephen C. Blacklow
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Abstract
Multiplex detection of biomolecules is important in bionanotechnology and clinical diagnostics. Multiplexing using engineered solutions such as microarrays, synthetic nanopores, and DNA barcodes is promising, but they require sophisticated design/engineering and typically yield semiquantitative information. Single-molecule fluorescence resonance energy transfer (smFRET) is an attractive tool in this regard as it enables both sensitive and quantitative detection. However, multiplexing with smFRET remains a great challenge as it requires either multiple excitation sources, an antenna system created by multiple FRET pairs, or multiple acceptors of the donor fluorophore, which complicates not only the labeling schemes but also data analysis, due to overlapping of FRET efficiencies ( EFRET). Here, we address these currently outstanding issues by designing interconvertible hairpin-based sensors (iHabSs) with nonoverlapping EFRET utilizing a single donor/acceptor pair and demonstrate a high-confidence multiplex detection of unlabeled nucleic acid sequences. We validated the reliability of our approach by systematically omitting one target at a time. Further, we demonstrate that these iHabSs are fully recyclable, sensitive with a limit of detection of ∼200 pM, and able to discriminate against single base mismatches. The multiplexed approach developed here has the potential to benefit the fields of biosensing and diagnostics by allowing simultaneous and quantitative detection of unlabeled nucleic acid biomarkers.
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Affiliation(s)
- Anisa Kaur
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, United States
| | - Kumar Sapkota
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, United States
| | - Soma Dhakal
- Department of Chemistry, Virginia Commonwealth University, 1001 West Main Street, Richmond, Virginia 23284, United States
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43
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Kirkness MWH, Forde NR. Single-Molecule Assay for Proteolytic Susceptibility: Force-Induced Collagen Destabilization. Biophys J 2019; 114:570-576. [PMID: 29414702 DOI: 10.1016/j.bpj.2017.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 12/01/2017] [Accepted: 12/11/2017] [Indexed: 01/07/2023] Open
Abstract
Force plays a key role in regulating dynamics of biomolecular structure and interactions, yet techniques are lacking to manipulate and continuously read out this response with high throughput. We present an enzymatic assay for force-dependent accessibility of structure that makes use of a wireless mini-radio centrifuge force microscope to provide a real-time readout of kinetics. The microscope is designed for ease of use, fits in a standard centrifuge bucket, and offers high-throughput, video-rate readout of individual proteolytic cleavage events. Proteolysis measurements on thousands of tethered collagen molecules show a load-enhanced trypsin sensitivity, indicating destabilization of the triple helix.
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Affiliation(s)
- Michael W H Kirkness
- Department of Molecular Biology and Biochemistry, Burnaby, British Columbia, Canada
| | - Nancy R Forde
- Department of Molecular Biology and Biochemistry, Burnaby, British Columbia, Canada; Department of Physics, Simon Fraser University, Burnaby, British Columbia, Canada.
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44
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Nathwani B, Shih WM, Wong WP. Force Spectroscopy and Beyond: Innovations and Opportunities. Biophys J 2018; 115:2279-2285. [PMID: 30447991 PMCID: PMC6302248 DOI: 10.1016/j.bpj.2018.10.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 10/08/2018] [Accepted: 10/25/2018] [Indexed: 12/26/2022] Open
Abstract
Life operates at the intersection of chemistry and mechanics. Over the years, we have made remarkable progress in understanding life from a biochemical perspective and the mechanics of life at the single-molecule scale. Yet the full integration of physical and mechanical models into mainstream biology has been impeded by technical and conceptual barriers, including limitations in our ability to 1) easily measure and apply mechanical forces to biological systems, 2) scale these measurements from single-molecule characterization to more complex biomolecular systems, and 3) model and interpret biophysical data in a coherent way across length scales that span single molecules to cells to multicellular organisms. In this manuscript, through a look at historical and recent developments in force spectroscopy techniques and a discussion of a few exemplary open problems in cellular biomechanics, we aim to identify research opportunities that will help us reach our goal of a more complete and integrated understanding of the role of force and mechanics in biological systems.
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Affiliation(s)
- Bhavik Nathwani
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts.
| | - William M Shih
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts
| | - Wesley P Wong
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts.
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45
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Kou L, Jin L, Lei H, Hu C, Li H, Hu X, Hu X. Real-time parallel 3D multiple particle tracking with single molecule centrifugal force microscopy. J Microsc 2018; 273:178-188. [PMID: 30489640 DOI: 10.1111/jmi.12773] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/16/2018] [Accepted: 11/20/2018] [Indexed: 12/20/2022]
Abstract
Real-time tracking of multiple particles is key for quantitative analysis of dynamic biophysical processes and materials science via time-lapse microscopy image data, especially for single molecule biophysical techniques, such as magnetic tweezers and centrifugal force microscopy. However, real-time multiple particle tracking with high resolution is limited by the current imaging processes or tracking algorithms. Here, we demonstrate 1 nm resolution in three dimensions in real-time with a graphics-processing unit (GPU) based on a compute unified device architecture (CUDA) parallel computing framework instead of only a central processing unit (CPU). We also explore the trade-offs between processing speed and size of the utilized regions of interest and a maximum speedup of 137 is achieved with the GPU compared with the CPU. Moreover, we utilize this method with our recently self-built centrifugal force microscope (CFM) in experiments that track multiple DNA-tethered particles. Our approach paves the way for high-throughput single molecule techniques with high resolution and efficiency. LAY DESCRIPTION: Particles are widely used as probes in life sciences through their motions. In single molecule techniques such as optical tweezers and magnetic tweezers, microbeads are used to study intermolecular or intramolecular interactions via beads tracking. Also tracking multiple beads' motions could study cell-cell or cell-ECM interactions in traction force microscopy. Therefore, particle tracking is of key important during these researches. However, parallel 3D multiple particle tracking in real-time with high resolution is a challenge either due to the algorithm or the program. Here, we combine the performance of CPU and CUDA-based GPU to make a hybrid implementation for particle tracking. In this way, a speedup of 137 is obtained compared the program before only with CPU without loss of accuracy. Moreover, we improve and build a new centrifugal force microscope for multiple single molecule force spectroscopy research in parallel. Then we employed our program into centrifugal force microscope for DNA stretching study. Our results not only demonstrate the application of this program in single molecule techniques, also indicate the capability of multiple single molecule study with centrifugal force microscopy.
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Affiliation(s)
- L Kou
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China
| | - L Jin
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China
| | - H Lei
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China
| | - C Hu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China
| | - H Li
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China.,Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | - X Hu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China
| | - X Hu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, China
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46
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Kirkness MWH, Korosec CS, Forde NR. Modified Pluronic F127 Surface for Bioconjugation and Blocking Nonspecific Adsorption of Microspheres and Biomacromolecules. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13550-13557. [PMID: 30303387 DOI: 10.1021/acs.langmuir.8b02877] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Many experiments and applications require the chemical coupling of target molecules to surfaces, during which the elimination of nonspecific interactions presents a difficult challenge. We report on a technologically accessible surface passivation and chemical conjugation method based on an NHS end-labeled F127 Pluronic block copolymer (F127-NHS). To quantify interactions between the F127-NHS surface and magnetic microspheres, we developed a simple assay: the microsphere adhesion by gravity, inversion, then counting, or "MAGIC" assay. To improve blocking of microspheres while maintaining the ability to chemically couple additional molecules, we implemented a pH-dependent two-step chemical modification process for amine microspheres. This process achieves an extremely high level of blocking nonspecific interactions (less than 2% nonspecific adhesion) for a variety of microsphere surface charges and chemical functionalities. We also demonstrate the ability to specifically tether magnetic microspheres to an F127-NHS surface, using single DNA molecules. Using the DNA microspheres, we establish the applicability of the surface for force spectroscopy (stable with an applied load >30 pN) via the massively parallel technique of centrifuge force microscopy. Finally, we demonstrate that the surface can be used in fluorescence studies with a fluorogenic peptide cleavage assay, with high levels of blocking achieved for both the fluorogenic peptide and trypsin. These results suggest applications including, but not limited to, single-molecule force spectroscopy and fluorescence, biosensors, medical implants, and anti-biofouling, which could make use of the F127-NHS surface.
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47
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Marras AE, Shi Z, Lindell MG, Patton RA, Huang CM, Zhou L, Su HJ, Arya G, Castro CE. Cation-Activated Avidity for Rapid Reconfiguration of DNA Nanodevices. ACS NANO 2018; 12:9484-9494. [PMID: 30169013 DOI: 10.1021/acsnano.8b04817] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The ability to design and control DNA nanodevices with programmed conformational changes has established a foundation for molecular-scale robotics with applications in nanomanufacturing, drug delivery, and controlling enzymatic reactions. The most commonly used approach for actuating these devices, DNA binding and strand displacement, allows devices to respond to molecules in solution, but this approach is limited to response times of minutes or greater. Recent advances have enabled electrical and magnetic control of DNA structures with sub-second response times, but these methods utilize external components with additional fabrication requirements. Here, we present a simple and broadly applicable actuation method based on the avidity of many weak base-pairing interactions that respond to changes in local ionic conditions to drive large-scale conformational transitions in devices on sub-second time scales. To demonstrate such ion-mediated actuation, we modified a DNA origami hinge with short, weakly complementary single-stranded DNA overhangs, whose hybridization is sensitive to cation concentrations in solution. We triggered conformational changes with several different types of ions including mono-, di-, and trivalent ions and also illustrated the ability to engineer the actuation response with design parameters such as number and length of DNA overhangs and hinge torsional stiffness. We developed a statistical mechanical model that agrees with experimental data, enabling effective interpretation and future design of ion-induced actuation. Single-molecule Förster resonance energy-transfer measurements revealed that closing and opening transitions occur on the millisecond time scale, and these transitions can be repeated with time resolution on the scale of one second. Our results advance capabilities for rapid control of DNA nanodevices, expand the range of triggering mechanisms, and demonstrate DNA nanomachines with tunable analog responses to the local environment.
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Affiliation(s)
| | - Ze Shi
- Department of NanoEngineering , University of California San Diego , La Jolla , California 92093 , United States
| | | | | | | | | | | | - Gaurav Arya
- Department of Mechanical Engineering and Materials Science , Duke University , Durham , North Carolina 27708 , United States
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48
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Johnson KC, Thomas WE. How Do We Know when Single-Molecule Force Spectroscopy Really Tests Single Bonds? Biophys J 2018; 114:2032-2039. [PMID: 29742396 PMCID: PMC5961468 DOI: 10.1016/j.bpj.2018.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 03/16/2018] [Accepted: 04/02/2018] [Indexed: 01/04/2023] Open
Abstract
Single-molecule force spectroscopy makes it possible to measure the mechanical strength of single noncovalent receptor-ligand-type bonds. A major challenge in this technique is to ensure that measurements reflect bonds between single biomolecules because the molecules cannot be directly observed. This perspective evaluates different methodologies for identifying and reducing the contribution of multiple molecule interactions to single-molecule measurements to help the reader design experiments or assess publications in the single-molecule force spectroscopy field. We apply our analysis to the large body of literature that purports to measure the strength of single bonds between biotin and streptavidin as a demonstration that measurements are only reproducible when the most reliable methods for ensuring single molecules are used.
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Affiliation(s)
- Keith C Johnson
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Wendy E Thomas
- Department of Bioengineering, University of Washington, Seattle, Washington.
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49
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Hoang T, Moskwa N, Halvorsen K. A 'smart' tube holder enables real-time sample monitoring in a standard lab centrifuge. PLoS One 2018; 13:e0195907. [PMID: 29659624 PMCID: PMC5901991 DOI: 10.1371/journal.pone.0195907] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 04/02/2018] [Indexed: 11/19/2022] Open
Abstract
The centrifuge is among the oldest and most widely used pieces of laboratory equipment, with significant applications that include clinical diagnostics and biomedical research. A major limitation of laboratory centrifuges is their "black box" nature, limiting sample observation to before and after centrifugation. Thus, optimized protocols require significant trial and error, while unoptimized protocols waste time by centrifuging longer than necessary or material due to incomplete sedimentation. Here, we developed an instrumented centrifuge tube receptacle compatible with several commercial benchtop centrifuges that can provide real-time sample analysis during centrifugation. We demonstrated the system by monitoring cell separations during centrifugation for different spin speeds, concentrations, buffers, cell types, and temperatures. We show that the collected data are valuable for analytical purposes (e.g. quality control), or as feedback to the user or the instrument. For the latter, we verified an adaptation where complete sedimentation turned off the centrifuge and notified the user by a text message. Our system adds new functionality to existing laboratory centrifuges, saving users time and providing useful feedback. This add-on potentially enables new analytical applications for an instrument that has remained largely unchanged for decades.
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Affiliation(s)
- Tony Hoang
- The RNA Institute, University at Albany, State University of New York, Albany, New York, United States of America
- Department of Chemistry, University at Albany, State University of New York, New York, United States of America
| | - Nicholas Moskwa
- Department of Biology, University at Albany, State University of New York, Albany, New York, United States of America
| | - Ken Halvorsen
- The RNA Institute, University at Albany, State University of New York, Albany, New York, United States of America
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50
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Su H, Liu Z, Liu Y, Ma VPY, Blanchard A, Zhao J, Galior K, Dyer RB, Salaita K. Light-Responsive Polymer Particles as Force Clamps for the Mechanical Unfolding of Target Molecules. NANO LETTERS 2018; 18:2630-2636. [PMID: 29589759 PMCID: PMC6110664 DOI: 10.1021/acs.nanolett.8b00459] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Single-molecule force spectroscopy techniques are powerful tools for investigating the mechanical unfolding of biomolecules. However, they are limited in throughput and require dedicated instrumentation. Here, we report a force-generating particle that can unfold target molecules on-demand. The particle consists of a plasmonic nanorod core encapsulated with a thermoresponsive polymer shell. Optical heating of the nanorod leads to rapid collapse of the polymer, thus transducing light into mechanical work to unfold target molecules. The illumination tunes the duration and degree of particle collapse, thus controlling the lifetime and magnitude of applied forces. Single-molecule fluorescence imaging showed reproducible mechanical unfolding of DNA hairpins. We also demonstrate the triggering of 50 different particles in <1 min, exceeding the speed of conventional atomic force microscopy. The polymer force clamp represents a facile and bottom-up approach to force manipulation.
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Affiliation(s)
- Hanquan Su
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - Zheng Liu
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - Yang Liu
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - Victor Pui-Yan Ma
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - Aaron Blanchard
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
| | - Jing Zhao
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - Kornelia Galior
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - R. Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
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