1
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Wani YM, Kovakas PG, Nikoubashman A, Howard MP. Mesoscale simulations of diffusion and sedimentation in shape-anisotropic nanoparticle suspensions. SOFT MATTER 2024; 20:3942-3953. [PMID: 38669202 DOI: 10.1039/d4sm00271g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
We determine the long-time self-diffusion coefficient and sedimentation coefficient for suspensions of nanoparticles with anisotropic shapes (octahedra, cubes, tetrahedra, and spherocylinders) as a function of nanoparticle concentration using mesoscale simulations. We use a discrete particle model for the nanoparticles, and we account for solvent-mediated hydrodynamic interactions between nanoparticles using the multiparticle collision dynamics method. Our simulations are compared to theoretical predictions and experimental data from existing literature, demonstrating good agreement in the majority of cases. Further, we find that the self-diffusion coefficient of the regular polyhedral shapes can be estimated from that of a sphere whose diameter is the average of their inscribed and circumscribed sphere diameters.
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Affiliation(s)
- Yashraj M Wani
- Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128, Mainz, Germany
| | | | - Arash Nikoubashman
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany.
- Institut für Theoretische Physik, Technische Universität Dresden, 01069 Dresden, Germany
| | - Michael P Howard
- Department of Chemical Engineering, Auburn University, Auburn, Alabama 36849, USA.
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2
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Kk S, Persson F, Fritzsche J, Beech JP, Tegenfeldt JO, Westerlund F. Fluorescence Microscopy of Nanochannel-Confined DNA. Methods Mol Biol 2024; 2694:175-202. [PMID: 37824005 DOI: 10.1007/978-1-0716-3377-9_9] [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
Stretching of DNA in nanoscale confinement allows for several important studies. The genetic contents of the DNA can be visualized on the single DNA molecule level, and the polymer physics of confined DNA and also DNA/protein and other DNA/DNA-binding molecule interactions can be explored. This chapter describes the basic steps to fabricate the nanostructures, perform the experiments, and analyze the data.
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Affiliation(s)
- Sriram Kk
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | | | - Joachim Fritzsche
- Department of Physics, Chalmers University of Technology, Gothenburg, Sweden
| | - Jason P Beech
- NanoLund and Department of Physics, Lund University, Lund, Sweden
| | | | - Fredrik Westerlund
- Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden.
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3
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He L, Charron M, Mensing P, Briggs K, Adams J, de Haan H, Tabard-Cossa V. DNA origami characterized via a solid-state nanopore: insights into nanostructure dimensions, rigidity and yield. NANOSCALE 2023; 15:14043-14054. [PMID: 37580994 DOI: 10.1039/d3nr01873c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Due to their programmability via specific base pairing, self-assembled DNA origami structures have proven to be useful for a wide variety of applications, including diagnostics, molecular computation, drug delivery, and therapeutics. Measuring and characterizing these structures is therefore of great interest and an important part of quality control. Here, we show the extent to which DNA nanostructures can be characterized by a solid-state nanopore; a non-destructive, label-free, single-molecule sensor capable of electrically detecting and characterizing charged biomolecules. We demonstrate that in addition to geometrical dimensions, nanopore sensing can provide information on the mechanical properties, assembly yield, and stability of DNA nanostructures. For this work, we use a model structure consisting of a 3 helix-bundle (3HB), i.e. three interconnected DNA double helices using a M13 scaffold folded twice on itself by short DNA staple strands, and translocate it through solid-state nanopores fabricated by controlled breakdown. We present detailed analysis of the passage characteristics of 3HB structures through nanopores under different experimental conditions which suggest that segments of locally higher flexibility are present along the nanostructure contour that allow for the otherwise rigid 3HB to fold inside nanopores. By characterizing partially melted 3HB structures, we find that locally flexible segments are likely due to short staple oligomers missing from the fully assembled structure. The 3HB used herein is a prototypical example to establish nanopores as a sensitive, non-destructive, and label-free alternative to conventional techniques such as gel electrophoresis with which to characterize DNA nanostructures.
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Affiliation(s)
- Liqun He
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
| | - Martin Charron
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
| | - Philipp Mensing
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
| | - Kyle Briggs
- Department of Physics, University of Ottawa, Ottawa, Ontario, Canada.
| | - Jonathan Adams
- Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada
| | - Hendrick de Haan
- Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada
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4
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Rehel DA, Polson JM. Equilibrium behaviour of two cavity-confined polymers: effects of polymer width and system asymmetries. SOFT MATTER 2023; 19:1092-1108. [PMID: 36625101 DOI: 10.1039/d2sm01413k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Experiments using nanofluidic devices have proven effective in characterizing the physical properties of polymers confined to small cavities. Two recent studies using such methods examined the organization and dynamics of two DNA molecules in box-like cavities with strong confinement in one direction and with square and elliptical cross sections in the lateral plane. Motivated by these experiments, we employ Monte Carlo and Brownian dynamics simulations to study the physical behaviour of two polymers confined to small cavities with shapes comparable to those used in the experiments. We quantify the effects of varying the following polymer properties and confinement dimensions on the organization and dynamics of the polymers: the polymer width, the polymer contour length ratio, the cavity cross-sectional area, and the degree of cavity elongation for cavities with rectangular and elliptical cross sections. We find that the tendency for polymers to segregate is enhanced by increasing polymer width. For sufficiently small cavities, increasing cavity elongation promotes segregation and localization of identical polymers to opposite sides of the cavity along its long axis. A free-energy barrier controls the rate of polymers swapping positions, and the observed dynamics are roughly in accord with predictions of a simple theoretical model. Increasing the contour length difference between polymers significantly affects their organization in the cavity. In the case of a large linear polymer co-trapped with a small ring polymer in an elliptical cavity, the small polymer tends to lie near the lateral confining walls, and especially at the cavity poles for highly elongated ellipses.
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Affiliation(s)
- Desiree A Rehel
- Department of Physics, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island, C1A 4P3, Canada.
| | - James M Polson
- Department of Physics, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island, C1A 4P3, Canada.
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5
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Adherent Moving of Polymers in Spherical Confined Binary Semiflexible Ring Polymer Mixtures. BIOPHYSICA 2022. [DOI: 10.3390/biophysica2040044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Based on the coarse-grained model, we used molecular dynamics methods to calculate and simulate a semiflexible long ring–semiflexible short ring blended polymer system confined in a hard sphere. We systematically studied the distribution and motion characteristics of the long ring chain. The results show that when the short ring is short enough (Lshort < 20), the long ring (Llong = 50) is separated from the blend system and then distributed against the inner wall. As the length of the short ring increases (Lshort ≥ 20), the long ring can no longer be separated from the blending system. Moreover, we found that the long ring demonstrates a random direction of adherent walking behavior on the inner surface of the hard sphere. The velocity of the long ring decreases with the increase in the short ring length Lshort. Specifically for Lshort ≥ 20, the system does not undergo phase separation and the speed of the long ring decreases sharply along with the long ring distributed inside the confined bulk. This is related to the inner wall layer moving faster than the inside bulk of the restricted system. Our simulation results can help us to understand the distribution of macromolecules in biological systems in confined systems, including the restricted chromosome partitioning distribution and packing structure of circular DNA molecules.
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6
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Duss M, Soto MA, Patrick BO, MacLachlan MJ. A Supramolecular Strategy for the Synthesis of Cyclic Oligomers and Polymers by Ring Expansion. Chemistry 2022; 28:e202200862. [DOI: 10.1002/chem.202200862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Indexed: 11/08/2022]
Affiliation(s)
- Michael Duss
- Department of Chemistry University of British Columbia 2036 Main Mall V6T 1Z1 Vancouver British Columbia Canada
| | - Miguel A. Soto
- Department of Chemistry University of British Columbia 2036 Main Mall V6T 1Z1 Vancouver British Columbia Canada
| | - Brian O. Patrick
- Department of Chemistry University of British Columbia 2036 Main Mall V6T 1Z1 Vancouver British Columbia Canada
| | - Mark J. MacLachlan
- Department of Chemistry University of British Columbia 2036 Main Mall V6T 1Z1 Vancouver British Columbia Canada
- University of British Columbia Stewart Blusson Quantum Matter Institute 2355 East Mall V6T 1Z4 Vancouver British Columbia Canada
- WPI Nano Life Science Institute Kanazawa University 920-1192 Kanazawa Japan
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7
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Tan CJ, Basak R, Yadav I, van Kan JA, Arluison V, van der Maarel JRC. Mobility of Bacterial Protein Hfq on dsDNA: Role of C-Terminus-Mediated Transient Binding. J Phys Chem B 2022; 126:1477-1482. [PMID: 35166115 DOI: 10.1021/acs.jpcb.1c10234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mobility of protein is fundamental in the machinery of life. Here, we have investigated the effect of DNA binding in conjunction with DNA segmental fluctuation (internal motion) of the bacterial Hfq master regulator devoid of its amyloid C-terminus domain. Hfq is one of the most abundant nucleoid associated proteins that shape the bacterial chromosome and is involved in several aspects of nucleic acid metabolism. Fluorescence microscopy has been used to track a C-terminus domain lacking mutant form of Hfq on double-stranded DNA, which is stretched by confinement to a rectangular nanofluidic channel. The mobility of the mutant is strongly accelerated with respect to the wild-type variant. Furthermore, it shows a reverse dependence on the internal motion of DNA, in that slower motion results in slower protein diffusion. The results demonstrate the subtle role of DNA internal motion in controlling the mobility of a nucleoid associated protein, and, in particular, the importance of transient binding and moving DNA strands out of the way.
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Affiliation(s)
- Chuan Jie Tan
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Rajib Basak
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Indresh Yadav
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Jeroen A van Kan
- Department of Physics, National University of Singapore, Singapore 117542, Singapore
| | - Véronique Arluison
- Université de Paris, UFR SDV, Paris 75006, France.,Laboratoire Léon Brillouin, CEA, CNRS, Université Paris Saclay, Gif-sur-Yvette 91191, France
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8
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Shepherd JW, Leake MC. The End Restraint Method for Mechanically Perturbing Nucleic Acids In Silico. Methods Mol Biol 2022; 2476:249-262. [PMID: 35635708 DOI: 10.1007/978-1-0716-2221-6_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Far from being a passive information store, the genome is a mechanically dynamic and diverse system in which torsion and tension fluctuate and combine to determine structure and help regulate gene expression. Much of this mechanical perturbation is due to molecular machines such as topoisomerases which must stretch and twist DNA as part of various functions including DNA repair and replication. While the broad-scale mechanical response of nucleic acids to tension and torsion is well characterized, detail at the single base pair level is beyond the limits of even super-resolution imaging. Here, we present a straightforward, flexible, and extensible umbrella-sampling protocol to twist and stretch nucleic acids in silico using the popular biomolecular simulation package Amber-though the principles we describe are applicable also to other packages such as GROMACS. We discuss how to set up the simulation system, decide force fields and solvation models, and equilibrate. We then introduce the torsionally constrained stretching protocol, and finally we present some analysis techniques we have used to characterize structural motif formation. Rather than defining forces or fictional pseudoatoms, we instead define a fixed translation of specified atoms between each umbrella-sampling step, which allows comparison with experiment without needing to estimate applied forces by simply using the fractional end-to-end displacement as a comparison metric. We hope that this easy-to-implement solution will be valuable for interrogating optical and magnetic tweezers data on nucleic acids at base pair resolution.
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Affiliation(s)
| | - Mark C Leake
- Departments of Physics and Biology, University of York, York, UK
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9
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Lee C, Kim YJ, Kim KS, Lee JY, Kim DN. Modulating the chemo-mechanical response of structured DNA assemblies through binding molecules. Nucleic Acids Res 2021; 49:12591-12599. [PMID: 34850119 PMCID: PMC8643692 DOI: 10.1093/nar/gkab1119] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/06/2021] [Accepted: 10/26/2021] [Indexed: 11/13/2022] Open
Abstract
Recent advances in DNA nanotechnology led the fabrication and utilization of various DNA assemblies, but the development of a method to control their global shapes and mechanical flexibilities with high efficiency and repeatability is one of the remaining challenges for the realization of the molecular machines with on-demand functionalities. DNA-binding molecules with intercalation and groove binding modes are known to induce the perturbation on the geometrical and mechanical characteristics of DNA at the strand level, which might be effective in structured DNA assemblies as well. Here, we demonstrate that the chemo-mechanical response of DNA strands with binding ligands can change the global shape and stiffness of DNA origami nanostructures, thereby enabling the systematic modulation of them by selecting a proper ligand and its concentration. Multiple DNA-binding drugs and fluorophores were applied to straight and curved DNA origami bundles, which demonstrated a fast, recoverable, and controllable alteration of the bending persistence length and the radius of curvature of DNA nanostructures. This chemo-mechanical modulation of DNA nanostructures would provide a powerful tool for reconfigurable and dynamic actuation of DNA machineries.
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Affiliation(s)
- Chanseok Lee
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Korea
| | - Young-Joo Kim
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Korea
| | - Kyung Soo Kim
- Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea
| | - Jae Young Lee
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Korea
| | - Do-Nyun Kim
- Institute of Advanced Machines and Design, Seoul National University, Seoul 08826, Korea.,Department of Mechanical Engineering, Seoul National University, Seoul 08826, Korea.,Institute of Engineering Research, Seoul National University, Seoul 08826, Korea
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10
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Ma Z, Dorfman KD. Interactions between two knots in nanochannel-confined DNA molecules. J Chem Phys 2021; 155:154901. [PMID: 34686050 DOI: 10.1063/5.0067076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Experimental data on the interaction between two knots in deoxyribonucleic acid (DNA) confined in nanochannels produced two particular behaviors of knot pairs along the DNA molecules: (i) widely separated knots experience an attractive interaction but only remain in close proximity for several seconds and (ii) knots tend to remain separated until one of the knots unravels at the chain end. The associated free energy profile of the knot-knot separation distance for an ensemble of DNA knots exhibits a global minimum when knots are separated, indicating that the separated knot state is more stable than the intertwined knot state, with dynamics in the separated knot state that are consistent with independent diffusion. The experimental observations of knot-knot interactions under nanochannel confinement are inconsistent with previous simulation-based and experimental results for stretched polymers under tension wherein the knots attract and then stay close to each other. This inconsistency is postulated to result from a weaker fluctuation-induced attractive force between knots under confinement when compared to the knots under tension, the latter of which experience larger fluctuations in transverse directions.
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Affiliation(s)
- Zixue Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
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11
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Morrin GT, Kienle DF, Schwartz DK. Diffusion of Short Semiflexible DNA Polymer Chains in Strong and Moderate Confinement. ACS Macro Lett 2021; 10:1191-1195. [PMID: 35549041 DOI: 10.1021/acsmacrolett.1c00470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In many technological applications, DNA is confined within nanoenvironments that are smaller than the size of the unconfined polymer in solution. However, the dependence of the diffusion coefficient on molecular weight and characteristic confinement dimension remains poorly understood in this regime. Here, convex lens-induced confinement (CLiC) was leveraged to examine how the diffusion of short DNA fragments varied as a function of slit height by using single-molecule fluorescence tracking microscopy. The diffusion coefficient followed approximate power law behavior versus confinement height, with exponents of 0.27 ± 0.01, 0.32 ± 0.02, and 0.42 ± 0.06 for 692, 1343, and 2686 base pair chains, respectively. The weak dependence on slit height suggests that shorter semiflexible chains may adopt increasingly rodlike conformations and therefore experience weaker excluded-volume interactions as the confinement dimension is reduced. The diffusion coefficient versus molecular weight also exhibited apparent power law behavior, with exponents that varied slightly (from -0.89 to -0.85) with slit height, consistent with hydrodynamic interactions intermediate between Rouse and Zimm model predictions.
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Affiliation(s)
- Gregory T Morrin
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel F Kienle
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering University of Colorado Boulder, Boulder, Colorado 80309, United States
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12
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de Mello LR, Porosk L, Lourenço TC, Garcia BBM, Costa CAR, Han SW, de Souza JS, Langel Ü, da Silva ER. Amyloid-like Self-Assembly of a Hydrophobic Cell-Penetrating Peptide and Its Use as a Carrier for Nucleic Acids. ACS APPLIED BIO MATERIALS 2021; 4:6404-6416. [PMID: 35006917 DOI: 10.1021/acsabm.1c00601] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Cell-penetrating peptides (CPPs) are a topical subject potentially exploitable for creating nanotherapeutics for the delivery of bioactive loads. These compounds are often classified into three major categories according to their physicochemical characteristics: cationic, amphiphilic, and hydrophobic. Among them, the group of hydrophobic CPPs has received increasing attention in recent years due to toxicity concerns posed by highly cationic CPPs. The hexapeptide PFVYLI (P, proline; F, phenylalanine; V, valine; Y, tyrosine; L, leucine; and I, isoleucine), a fragment derived from the C-terminal portion of α1-antitrypsin, is a prototypal example of hydrophobic CPP. This sequence shows reduced cytotoxicity and a capacity of nuclear localization, and its small size readily hints at its suitability as a building block to construct nanostructured materials. In this study, we examine the self-assembling properties of PFVYLI and investigate its ability to form noncovalent complexes with nucleic acids. By using a combination of biophysical tools including synchrotron small-angle X-ray scattering and atomic force microscopy-based infrared spectroscopy, we discovered that this CPP self-assembles into discrete nanofibrils with remarkable amyloidogenic features. Over the course of days, these fibrils coalesce into rodlike crystals that easily reach the micrometer range. Despite lacking cationic residues in the composition, PFVYLI forms noncovalent complexes with nucleic acids that retain β-sheet pairing found in amyloid aggregates. In vitro vectorization experiments performed with double-stranded DNA fragments indicate that complexes promote the internalization of nucleic acids, revealing that tropism toward cell membranes is preserved upon complexation. On the other hand, transfection assays with splice-correction oligonucleotides (SCOs) for luciferase expression show limited bioactivity across a narrow concentration window, suggesting that the propensity to form amyloidogenic aggregates may trigger endosomal entrapment. We anticipate that the findings presented here open perspectives for using this archetypical hydrophobic CPP in the fabrication of nanostructured scaffolds, which potentially integrate properties of amyloids and translocation capabilities of CPPs.
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Affiliation(s)
- Lucas R de Mello
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Ly Porosk
- Institute of Technology, University of Tartu, Tartu 50411, Estonia
| | - Thiago C Lourenço
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Bianca B M Garcia
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Carlos A R Costa
- Laboratório Nacional de Nanotecnologia (LNNano), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas 13083-861, Brazil
| | - Sang W Han
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
| | - Juliana S de Souza
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André 09210580, Brazil
| | - Ülo Langel
- Institute of Technology, University of Tartu, Tartu 50411, Estonia
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm SE-10691, Sweden
| | - Emerson R da Silva
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil
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13
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Polson JM, Rehel DA. Equilibrium organization, conformation, and dynamics of two polymers under box-like confinement. SOFT MATTER 2021; 17:5792-5805. [PMID: 34028486 DOI: 10.1039/d1sm00308a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Motivated by recent nanofluidics experiments, we use Brownian dynamics and Monte Carlo simulations to study the conformation, organization and dynamics of two polymer chains confined to a single box-like cavity. The polymers are modeled as flexible bead-spring chains, and the box has a square cross-section of side length L and a height that is small enough to compress the polymers in that dimension. For sufficiently large L, the system behaviour approaches that of an isolated polymer in a slit. However, the combined effects of crowding and confinement on the polymer organization, conformation and equilibrium dynamics become significant when where is the transverse radius of gyration for a slit geometry. In this regime, the centre-of-mass probability distribution in the transverse plane exhibits a depletion zone near the centre of the cavity (except at very small L) and a 4-fold symmetry with quasi-discrete positions. Reduction in polymer size with decreasing L arises principally from confinement rather than inter-polymer crowding. By contrast, polymer diffusion and internal motion are strongly affected by inter-polymer crowding. The two polymers tend to occupy opposite positions relative to the box centre, about which they diffuse relatively freely. Qualitatively, this static and dynamical behaviour differs significantly from that previously observed for confinement of two polymers to a narrow channel. The simulation results for a suitably chosen box width are qualitatively consistent with results from a recent experimental study of two λ-DNA chains confined to a nanofluidic cavity.
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Affiliation(s)
- James M Polson
- Department of Physics, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island C1A 4P3, Canada.
| | - Desiree A Rehel
- Department of Physics, University of Prince Edward Island, 550 University Ave., Charlottetown, Prince Edward Island C1A 4P3, Canada.
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14
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Ma Z, Dorfman KD. Diffusion of Knotted DNA Molecules in Nanochannels in the Extended de Gennes Regime. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00143] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zixue Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota−Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota−Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, United States
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15
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Basak R, Rosencrans W, Yadav I, Yan P, Berezhnoy NV, Chen Q, van Kan JA, Nordenskiöld L, Zinchenko A, van der Maarel JRC. Internal Motion of Chromatin Fibers Is Governed by Dynamics of Uncompressed Linker Strands. Biophys J 2020; 119:2326-2334. [PMID: 33121944 PMCID: PMC7732777 DOI: 10.1016/j.bpj.2020.10.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/23/2020] [Accepted: 10/13/2020] [Indexed: 11/25/2022] Open
Abstract
Chromatin compaction and internal motion are fundamental aspects of gene expression regulation. Here, we have investigated chromatin fibers comprising recombinant histone octamers reconstituted with double-stranded bacteriophage T4-DNA. The size of the fibers approaches the typical size of genomic topologically associated domains. Atomic force and fluorescence (correlation) microscopy have been used to assess the structural organization, histone-induced compaction, and internal motion. In particular, the fibers are stretched on arrays of nanochannels, each channel with a diameter of 60 or 125 nm. Major intrafiber segregation and fast internal fluctuations are observed. Full compaction was only achieved by triggering an attractive nucleosome interaction through the addition of magnesium cations. Besides compaction, histone complexation results in a dramatic decrease in the fiber's relaxation time. The relaxation times are similar to those of naked DNA with a comparable stretch, which indicates that internal motion is governed by the dynamics of uncompressed linker strands. Furthermore, the main reorganization process is association-dissociation of individually compacted regions. We surmise that the modulation of chromatin's internal motion by histone complexation might have implications for transcriptional bursting.
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Affiliation(s)
- Rajib Basak
- Department of Physics, National University of Singapore, Singapore, Republic of Singapore
| | - William Rosencrans
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Indresh Yadav
- Department of Physics, National University of Singapore, Singapore, Republic of Singapore
| | - Peiyan Yan
- Department of Physics, National University of Singapore, Singapore, Republic of Singapore
| | - Nikolay V Berezhnoy
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Qinming Chen
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Jeroen A van Kan
- Department of Physics, National University of Singapore, Singapore, Republic of Singapore
| | - Lars Nordenskiöld
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Anatoly Zinchenko
- Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan
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16
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Liu Y, Zografos K, Fidalgo J, Duchêne C, Quintard C, Darnige T, Filipe V, Huille S, du Roure O, Oliveira MSN, Lindner A. Optimised hyperbolic microchannels for the mechanical characterisation of bio-particles. SOFT MATTER 2020; 16:9844-9856. [PMID: 32996949 DOI: 10.1039/d0sm01293a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The transport of bio-particles in viscous flows exhibits a rich variety of dynamical behaviour, such as morphological transitions, complex orientation dynamics or deformations. Characterising such complex behaviour under well controlled flows is key to understanding the microscopic mechanical properties of biological particles as well as the rheological properties of their suspensions. While generating regions of simple shear flow in microfluidic devices is relatively straightforward, generating straining flows in which the strain rate is maintained constant for a sufficiently long time to observe the objects' morphologic evolution is far from trivial. In this work, we propose an innovative approach based on optimised design of microfluidic converging-diverging channels coupled with a microscope-based tracking method to characterise the dynamic behaviour of individual bio-particles under homogeneous straining flow. The tracking algorithm, combining a motorised stage and a microscopy imaging system controlled by external signals, allows us to follow individual bio-particles transported over long-distances with high-quality images. We demonstrate experimentally the ability of the numerically optimised microchannels to provide linear velocity streamwise gradients along the centreline of the device, allowing for extended consecutive regions of homogeneous elongation and compression. We selected three test cases (DNA, actin filaments and protein aggregates) to highlight the ability of our approach for investigating dynamics of objects with a wide range of sizes, characteristics and behaviours of relevance in the biological world.
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Affiliation(s)
- Yanan Liu
- PMMH, CNRS, ESPCI Paris PSL, Sorbonne Université, Université de Paris, F-75005, Paris, France.
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17
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Tu MQ, Lee M, Robertson-Anderson RM, Schroeder CM. Direct Observation of Ring Polymer Dynamics in the Flow-Gradient Plane of Shear Flow. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c01362] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Michael Q. Tu
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Megan Lee
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, United States
| | - Rae M. Robertson-Anderson
- Department of Physics and Biophysics, University of San Diego, San Diego, California 92110, United States
| | - Charles M. Schroeder
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Department of Materials Science and Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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18
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Yadav I, Basak R, Yan P, van Kan JA, Arluison V, van der Maarel JRC. Role of Internal DNA Motion on the Mobility of a Nucleoid-Associated Protein. J Phys Chem Lett 2020; 11:8424-8429. [PMID: 32930601 DOI: 10.1021/acs.jpclett.0c02251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Protein transport on DNA is at the core of the machinery of life. Here we investigated the influence of DNA internal motion on the mobility of Hfq, which is involved in several aspects of nucleic acid metabolism and is one of the nucleoid-associated proteins that shape the bacterial chromosome. Fluorescence microscopy was used to follow Hfq on double-stranded DNA that was stretched by confinement to a channel with a diameter of 125 nm. The protein mobility shows a strong dependence on the internal motion of DNA in that slower motion results in faster protein diffusion. A model of released diffusion is proposed that is based on three-dimensional diffusion through the interior of the DNA coil interspersed by periods in which the protein is immobilized in a bound state. We surmise that the coupling between DNA internal motion and protein mobility has important implications for DNA metabolism and protein-binding-related regulation of gene expression.
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Affiliation(s)
- Indresh Yadav
- Department of Physics, National University of Singapore, Singapore 117542
| | - Rajib Basak
- Department of Physics, National University of Singapore, Singapore 117542
| | - Peiyan Yan
- Department of Physics, National University of Singapore, Singapore 117542
| | - Jeroen A van Kan
- Department of Physics, National University of Singapore, Singapore 117542
| | - Véronique Arluison
- Université de Paris, UFR SDV, 75006 Paris, France
- Laboratoire Léon Brillouin, CEA, CNRS, Université Paris Saclay, 91191 Gif-sur-Yvette, France
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19
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Affiliation(s)
- Zixue Ma
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
| | - Kevin D. Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota, Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States
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20
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Zhang Y, Zhang X, Zhang W, Zhang W. Effects of Psoralen on Histone-DNA Interactions Studied by Using Atomic Force Microscopy. Macromol Rapid Commun 2020; 41:e2000017. [PMID: 32686170 DOI: 10.1002/marc.202000017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/26/2020] [Indexed: 11/09/2022]
Abstract
The investigation of the DNA-histone interactions and factors that affect such interactions in the nucleosome is essential for understanding the role of chromatin organization in all cellular processes involved in the repair, transcription, and replication of the eukaryotic genome. As a kind of photosensitive molecule, psoralen (PSO) is used in the treatment of skin disease with ultraviolet light (PSO and ultra violet light, type A). The effect of treatment is remarkable, but the side effect is also obvious. PSO can be embedded in a 5' TA sequence in double-stranded DNA (dsDNA), and dsDNA is mainly wrapped around a histone octamer to form a nucleosome structure in human cells. Therefore, it is very necessary to explore the influence of PSO on DNA-histone interactions. To this end, the binding specificity and mode of DNA and histone in the presence or absence of PSO are investigated systematically. The results show that the presence of PSO (no matter if there is ultra violet light treatment) can increase the overall probability of histone binding to dsDNA while lowering the selectivity of histone binding to the specific DNA sequence in vitro. In addition, the increase of solution ionic strength can lower the ratio of histone binding to nonspecific DNA.
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Affiliation(s)
- Yingqi Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, China
| | - Xiaonong Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, China
| | - Wei Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, China
| | - Wenke Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012, China
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21
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Serres S, Tardin C, Salomé L. Single-Molecule Sensing of DNA Intercalating Drugs in Water. Anal Chem 2020; 92:8151-8158. [PMID: 32396338 DOI: 10.1021/acs.analchem.0c00184] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The occurrence of pharmaceutical residues in surface water is raising environmental concern. To accompany the evolution of measures for natural resources protection, sensing methods enabling sensitive and rapid water quality monitoring are needed. We recently managed the parallelization of the Tethered Particle Motion (TPM), a single molecule technique, sensitive to the conformational changes of DNA. Here, we investigate the capacity of high throughput TPM (htTPM) to detect drugs that intercalate into DNA. As a proof-of-concept we analyze the htTPM signal for two DNA intercalating dyes, namely, YOYO-1 and SYTOX orange. The efficient detection of intercalating drugs is then demonstrated with doxorubicin. We further evaluate the possibility to detect carbamazepine, an antiepileptic massively prescribed and persistent in water, which had been described to interact with DNA through intercalation. Our results corroborated by other techniques show that, in fact, carbamazepine is not a DNA intercalator. The comparison of the results obtained with different aqueous buffers and solutions allows us to identify optimal conditions for the monitoring of intercalation compounds by htTPM.
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Affiliation(s)
- Sandra Serres
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Catherine Tardin
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Laurence Salomé
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
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22
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Mello LR, Hamley IW, Castelletto V, Garcia BBM, Lourenço TC, Vassiliades SV, Alves WA, Han SW, Silva ER. Self-assembly and intracellular delivery of DNA by a truncated fragment derived from the Trojan peptide Penetratin. SOFT MATTER 2020; 16:4746-4755. [PMID: 32329496 DOI: 10.1039/d0sm00347f] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Penetratin is a short Trojan peptide that attracts great interest in biomedical research for its capacity to translocate biological membranes. Herein, we study in detail both self-assembly and intracellular delivery of DNA by the heptamer KIWFQNR, a truncated peptide derived from Penetratin. This shortened sequence possesses a unique design with bolaamphiphilic characteristics that preserves the longest noncationic amino acid portion found in Penetratin. These features convey amphipathicity to assist self-assembly and make it a suitable model for exploring the role of hydrophobic residues for peptide interaction and cell uptake. We show that the fragment forms peptiplexes (i.e., peptide-DNA complexes), and aggregates into long nanofibers with clear β-sheet signature. The supramolecular structure of nanofibers is likely composed of DNA cores surrounded by a peptide shell to which the double helix behaves as a template and induces fibrillization. A nucleation and growth mechanism proceeding through liquid-liquid phase separation of coacervates is proposed for describing the self-assembly of peptiplexes. We also demonstrate that peptiplexes deliver double-stranded 200 bp DNA into HeLa cells, indicating its potential for preparing non-viral vectors for oligonucleotides through noncovalent strategies. Since the main structural features of native Penetratin are conserved in this simpler fragment, our findings also highlight the role of uncharged amino acids for structuration, and thus for the ability of Penetratin to cross cell membranes.
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Affiliation(s)
- Lucas R Mello
- Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo 04023-062, Brazil.
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23
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Haque FM, Grayson SM. The synthesis, properties and potential applications of cyclic polymers. Nat Chem 2020; 12:433-444. [DOI: 10.1038/s41557-020-0440-5] [Citation(s) in RCA: 150] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 02/14/2020] [Indexed: 11/09/2022]
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24
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Oh M, Jayasooriya V, Woo SO, Nawarathna D, Choi Y. Selective Manipulation of Biomolecules with Insulator-Based Dielectrophoretic Tweezers. ACS APPLIED NANO MATERIALS 2020; 3:797-805. [PMID: 32587952 PMCID: PMC7316190 DOI: 10.1021/acsanm.9b02302] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Insulator-based dielectrophoretic (iDEP) trapping, separating, and concentrating nanoscale objects is carried out using a non-metal, unbiased, mobile tip acing as a tweezers. The spatial control and manipulation of fluorescently-labeled polystyrene particles and DNA were performed to demonstrate the feasibility of the iDEP tweezers. Frequency-dependent iDEP tweezers' strength and polarity were quantitatively determined using two theoretical approaches to DNA, which resulted in a factor of 2 ~ 40 differences between them. In either approach, the strength of iDEP was at least 4-order of magnitude stronger than the thermal force, indicating iDEP was a dominant force for trapping, holding, and separating DNA. The trapping strength and volume of the iDEP tweezers were also determined, which further supports direct capture and manipulation of DNA at the tip end.
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Affiliation(s)
- Myungkeun Oh
- Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Vidura Jayasooriya
- Department of Electrical and Computer Engineering, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Sung Oh Woo
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Dharmakeerthi Nawarathna
- Department of Electrical and Computer Engineering, North Dakota State University, Fargo, North Dakota 58108, USA
| | - Yongki Choi
- Materials and Nanotechnology Program, North Dakota State University, Fargo, North Dakota 58108, USA
- Department of Physics, North Dakota State University, Fargo, North Dakota 58108, USA
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25
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Sachdev S, Muralidharan A, Choudhary DK, Perrier DL, Rems L, Kreutzer MT, Boukany PE. DNA translocation to giant unilamellar vesicles during electroporation is independent of DNA size. SOFT MATTER 2019; 15:9187-9194. [PMID: 31595286 DOI: 10.1039/c9sm01274e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Delivery of naked DNA molecules into living cells via physical disruption of the membrane under electric pulses has potential biomedical applications ranging from gene electro-transfer, electro-chemotherapy, to gene therapy, yet the mechanisms involved in DNA transport remain vague. To investigate the mechanism of DNA translocation across the cell membrane, giant unilamellar vesicles (GUVs) were electroporated in the presence of DNA molecules keeping the size of the DNA molecules as a variable parameter. We experimentally determined the translocation efficiency for each size of the DNA molecule, to compare the results with the existing and conflicting theories of the translocation mechanism i.e. stochastic threading and bulk electrophoresis. We observed that the translocation efficiency is independent of DNA size (ranging from 25-20 000 bp, bp = base pairs), implying that DNA molecules translocate freely across the electro-pores in the lipid membrane in their native polymer conformation, as opposed to unravelling and threading through the electro-pore. Bulk electrophoretic mobility determines the relationship between translocation efficiency and the size of the DNA molecule. This research provides experimental evidence of the mechanistic understanding of DNA translocation across lipid membranes which is essential for devising efficient and predictable protocols for electric field mediated naked DNA delivery.
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Affiliation(s)
- Shaurya Sachdev
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Aswin Muralidharan
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Dipendra K Choudhary
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Dayinta L Perrier
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Lea Rems
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Michiel T Kreutzer
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
| | - Pouyan E Boukany
- Department of Chemical Engineering, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands.
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26
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Sahoo AK, Bagchi B, Maiti PK. Understanding enhanced mechanical stability of DNA in the presence of intercalated anticancer drug: Implications for DNA associated processes. J Chem Phys 2019; 151:164902. [PMID: 31675856 DOI: 10.1063/1.5117163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Most of the anticancer drugs bind to double-stranded DNA (dsDNA) by intercalative-binding mode. Although experimental studies have become available recently, a molecular-level understanding of the interactions between the drug and dsDNA that lead to the stability of the intercalated drug is lacking. Of particular interest are the modifications of the mechanical properties of dsDNA observed in experiments. The latter could affect many biological functions, such as DNA transcription and replication. Here, we probe, via all-atom molecular dynamics (MD) simulations, the change in the mechanical properties of intercalated drug-DNA complexes for two intercalators, daunomycin and ethidium. We find that, upon drug intercalation, the stretch modulus of DNA increases significantly, whereas its persistence length and bending modulus decrease. Steered MD simulations reveal that it requires higher forces to stretch the intercalated dsDNA complexes than the normal dsDNA. Adopting various pulling protocols to study force-induced DNA melting, we find that the dissociation of dsDNA becomes difficult in the presence of intercalators. The results obtained here provide a plausible mechanism of function of the anticancer drugs, i.e., via altering the mechanical properties of DNA. We also discuss long-time consequences of using these drugs, which require further in vivo investigations.
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Affiliation(s)
- Anil Kumar Sahoo
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
| | - Biman Bagchi
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Prabal K Maiti
- Center for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012, India
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27
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Shin E, Kim W, Lee S, Bae J, Kim S, Ko W, Seo HS, Lim S, Lee HS, Jo K. Truncated TALE-FP as DNA Staining Dye in a High-salt Buffer. Sci Rep 2019; 9:17197. [PMID: 31748571 PMCID: PMC6868158 DOI: 10.1038/s41598-019-53722-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/05/2019] [Indexed: 01/19/2023] Open
Abstract
Large DNA molecules are a promising platform for in vitro single-molecule biochemical analysis to investigate DNA-protein interactions by fluorescence microscopy. For many studies, intercalating fluorescent dyes have been primary DNA staining reagents, but they often cause photo-induced DNA breakage as well as structural deformation. As a solution, we previously developed several fluorescent-protein DNA-binding peptides or proteins (FP-DBP) for reversibly staining DNA molecules without structural deformation or photo-induced damage. However, they cannot stain DNA in a condition similar to a physiological salt concentration that most biochemical reactions require. Given these concerns, here we developed a salt-tolerant FP-DBP: truncated transcription activator-like effector (tTALE-FP), which can stain DNA up to 100 mM NaCl. Moreover, we found an interesting phenomenon that the tTALE-FP stained DNA evenly in 1 × TE buffer but showed AT-rich specific patterns from 40 mM to 100 mM NaCl. Using an assay based on fluorescence resonance energy transfer, we demonstrated that this binding pattern is caused by a higher DNA binding affinity of tTALE-FP for AT-rich compared to GC-rich regions. Finally, we used tTALE-FP in a single molecule fluorescence assay to monitor real-time restriction enzyme digestion of single DNA molecules. Altogether, our results demonstrate that this protein can provide a useful alternative as a DNA stain over intercalators.
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Affiliation(s)
- Eunji Shin
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Woojung Kim
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Seonghyun Lee
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Jaeyoung Bae
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Sanggil Kim
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Wooseok Ko
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea
| | - Ho Seong Seo
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Korea
| | - Sangyong Lim
- Research Division for Biotechnology, Korea Atomic Energy Research Institute, Jeongeup, 580-185, Korea
| | - Hyun Soo Lee
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea.
| | - Kyubong Jo
- Department of Chemistry and Interdisciplinary Program of Integrated Biotech, Sogang University, 1 Shinsudong, Mapogu, Seoul, 04107, Korea.
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28
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Lee S, Kawamoto Y, Vaijayanthi T, Park J, Bae J, Kim-Ha J, Sugiyama H, Jo K. TAMRA-polypyrrole for A/T sequence visualization on DNA molecules. Nucleic Acids Res 2019; 46:e108. [PMID: 29931115 PMCID: PMC6182132 DOI: 10.1093/nar/gky531] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/29/2018] [Indexed: 01/23/2023] Open
Abstract
Fluorophore-linked, sequence-specific DNA binding reagents can visualize sequence information on a large DNA molecule. In this paper, we synthesized newly designed TAMRA-linked polypyrrole to visualize adenine and thymine base pairs. A fluorescent image of the stained DNA molecule generates an intensity profile based on A/T frequency, revealing a characteristic sequence composition pattern. Computer-aided comparison of this intensity pattern with the genome sequence allowed us to determine the DNA sequence on a visualized DNA molecule from possible intensity profile pattern candidates for a given genome. Moreover, TAMRA-polypyrrole offers robust advantages for single DNA molecule detection: no fluorophore-mediated photocleavage and no structural deformation, since it exhibits a sequence-specific pattern alone without the use of intercalating dyes such as YOYO-1. Accordingly, we were able to identify genomic DNA fragments from Escherichia coli cells by aligning them to the genomic A/T frequency map based on TAMRA-polypyrrole-generated intensity profiles. Furthermore, we showed band and interband patterns of polytene chromosomal DNA stained with TAMRA-polypyrrole because it prefers to bind AT base pairs.
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Affiliation(s)
- Seonghyun Lee
- Department of Chemistry and Program of Integrated Biotechnology, Sogang University, Seoul 04107, Republic of Korea
| | - Yusuke Kawamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Thangavel Vaijayanthi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Jihyun Park
- Department of Chemistry and Program of Integrated Biotechnology, Sogang University, Seoul 04107, Republic of Korea
| | - Jaeyoung Bae
- Department of Chemistry and Program of Integrated Biotechnology, Sogang University, Seoul 04107, Republic of Korea
| | - Jeongsil Kim-Ha
- Department of Integrative Bioscience and Biotechnology, College of Life Sciences, Sejong University, Seoul 05006, Republic of Korea
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Kyubong Jo
- Department of Chemistry and Program of Integrated Biotechnology, Sogang University, Seoul 04107, Republic of Korea
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29
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Jia F, Hébraud P, Han K, Wang J, Liang X, Liu B. Flexibility and thermal dynamic stability increase of dsDNA induced by Ru(bpy) 2dppz 2+ based on AFM and HRM technique. BMC Chem 2019; 13:68. [PMID: 31384815 PMCID: PMC6661754 DOI: 10.1186/s13065-019-0584-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 05/02/2019] [Indexed: 01/05/2023] Open
Abstract
Ru(bpy)2dppz2+ has been widely used as a probe for exploring the structure of double-stranded DNA (dsDNA). The flexibility change of DNA helix is important in many of its biological functions but not well understood. Here, flexibility change of dsDNA helix caused by intercalation with Ru(bpy)2dppz2+ was investigated using the atomic force microscopy. At first, the interactions between ruthenium complex and dsDNA helix were characterized and the binding site size (p = 2.87 bp) and binding constant (Ka = 5.9 * 107 M−1) were determined by the relative extension of DNA helix using the equation of McGhee and von Hippel. By measuring intercalator-induced DNA elongation and the mean square of end-to-end distance at different molar ratios of Ru(bpy)2dppz2+ to dsDNA, the changes of persistence length under different ruthenium concentrations were determined by the worm-like chain model. We found that the persistence length of dsDNA decreased with increasing Ru(bpy)2dppz2+ concentration, demonstrating that the flexibility of dsDNA obviously enhanced due to the intercalation. Especially, the persistence length changed greatly from 54 to 34 nm on changing the molar ratio of ruthenium to dsDNA from 0 to 0.2. We speculated that the intercalation of dsDNA with Ru(bpy)2dppz2+ resulted in local deformation or bending of the DNA duplex. In addition, the thermal dynamic stability of DNA helix was measured with high resolution melting method which revealed the increase in thermal dynamic stability of DNA helix due to the ruthenium intercalation.
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Affiliation(s)
- Fuchao Jia
- 1Laboratory of Functional Molecules and Materials, School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo, 255000 China
| | - Pascal Hébraud
- 2Institut de Physique et Chimie des Matériaux de Strasbourg/Centre National de la Recherche Scientifique, University of Strasbourg, 67034 Strasbourg, France
| | - Kezhen Han
- 1Laboratory of Functional Molecules and Materials, School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo, 255000 China
| | - Jing Wang
- 3College of Food Science and Engineering, Ocean University of China, Qingdao, 266003 China
| | - Xingguo Liang
- 3College of Food Science and Engineering, Ocean University of China, Qingdao, 266003 China
| | - Bo Liu
- 1Laboratory of Functional Molecules and Materials, School of Physics and Optoelectronic Engineering, Shandong University of Technology, Zibo, 255000 China
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30
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Wunsch BH, Kim SC, Gifford SM, Astier Y, Wang C, Bruce RL, Patel JV, Duch EA, Dawes S, Stolovitzky G, Smith JT. Gel-on-a-chip: continuous, velocity-dependent DNA separation using nanoscale lateral displacement. LAB ON A CHIP 2019; 19:1567-1578. [PMID: 30920559 DOI: 10.1039/c8lc01408f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
We studied the trajectories of polymers being advected while diffusing in a pressure driven flow along a periodic pillar nanostructure known as nanoscale deterministic lateral displacement (nanoDLD) array. We found that polymers follow different trajectories depending on their length, flow velocity and pillar array geometry, demonstrating that nanoDLD devices can be used as a continuous polymer fractionation tool. As a model system, we used double-stranded DNA (dsDNA) with various contour lengths and demonstrated that dsDNA in the range of 100-10 000 base pairs (bp) can be separated with a size-selective resolution of 200 bp. In contrast to spherical colloids, a polymer elongates by shear flow and the angle of polymer trajectories with respect to the mean flow direction decreases as the mean flow velocity increases. We developed a phenomenological model that explains the qualitative dependence of the polymer trajectories on the gap size and on the flow velocity. Using this model, we found the optimal separation conditions for dsDNA of different sizes and demonstrated the separation and extraction of dsDNA fragments with over 75% recovery and 3-fold concentration. Importantly, this velocity dependence provides a means of fine-tuning the separation efficiency and resolution, independent of the nanoDLD pillar geometry.
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Affiliation(s)
- Benjamin H Wunsch
- IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
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31
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Anticooperative Binding Governs the Mechanics of Ethidium-Complexed DNA. Biophys J 2019; 116:1394-1405. [PMID: 30954211 DOI: 10.1016/j.bpj.2019.03.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 03/12/2019] [Indexed: 01/17/2023] Open
Abstract
DNA intercalators bind nucleic acids by stacking between adjacent basepairs. This causes a considerable elongation of the DNA backbone as well as untwisting of the double helix. In the past few years, single-molecule mechanical experiments have become a common tool to characterize these deformations and to quantify important parameters of the intercalation process. Parameter extraction typically relies on the neighbor-exclusion model, in which a bound intercalator prevents intercalation into adjacent sites. Here, we challenge the neighbor-exclusion model by carefully quantifying and modeling the force-extension and twisting behavior of single ethidium-complexed DNA molecules. We show that only an anticooperative ethidium binding that allows for a disfavored but nonetheless possible intercalation into nearest-neighbor sites can consistently describe the mechanical behavior of intercalator-bound DNA. At high ethidium concentrations and elevated mechanical stress, this causes an almost complete occupation of nearest-neighbor sites and almost a doubling of the DNA contour length. We furthermore show that intercalation into nearest-neighbor sites needs to be considered when estimating intercalator parameters from zero-stress elongation and twisting data. We think that the proposed anticooperative binding mechanism may also be applicable to other intercalating molecules.
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32
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Kubota T, Lloyd K, Sakashita N, Minato S, Ishida K, Mitsui T. Clog and Release, and Reverse Motions of DNA in a Nanopore. Polymers (Basel) 2019; 11:polym11010084. [PMID: 30960068 PMCID: PMC6401990 DOI: 10.3390/polym11010084] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2018] [Revised: 12/28/2018] [Accepted: 01/03/2019] [Indexed: 01/29/2023] Open
Abstract
Motions of circular and linear DNA molecules of various lengths near a nanopore of 100 or 200 nm diameter were experimentally observed and investigated by fluorescence microscopy. The movement of DNA molecules through nanopores, known as translocation, is mainly driven by electric fields near and inside the pores. We found significant clogging of nanopores by DNA molecules, particularly by circular DNA and linear T4 DNA (165.65 kbp). Here, the probabilities of DNA clogging events, depending on the DNA length and shape—linear or circular—were determined. Furthermore, two distinct DNA motions were observed: clog and release by linear T4 DNA, and a reverse direction motion at the pore entrance by circular DNA, after which both molecules moved away from the pore. Finite element method-based numerical simulations were performed. The results indicated that DNA molecules with pores 100–200 nm in diameter were strongly influenced by opposing hydrodynamic streaming flow, which was further enhanced by bulky DNA configurations.
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Affiliation(s)
- Tomoya Kubota
- Department of Mathematics and Physics, Aoyama-Gakuin University, Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.
| | - Kento Lloyd
- Department of Mathematics and Physics, Aoyama-Gakuin University, Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.
| | - Naoto Sakashita
- Department of Mathematics and Physics, Aoyama-Gakuin University, Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.
| | - Seiya Minato
- Department of Mathematics and Physics, Aoyama-Gakuin University, Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.
| | - Kentaro Ishida
- Department of Mathematics and Physics, Aoyama-Gakuin University, Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.
| | - Toshiyuki Mitsui
- Department of Mathematics and Physics, Aoyama-Gakuin University, Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan.
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33
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Lee S, Lee Y, Kim Y, Wang C, Park J, Jung GY, Chen Y, Chang R, Ikeda S, Sugiyama H, Jo K. Nanochannel-Confined TAMRA-Polypyrrole Stained DNA Stretching by Varying the Ionic Strength from Micromolar to Millimolar Concentrations. Polymers (Basel) 2018; 11:E15. [PMID: 30959999 PMCID: PMC6401831 DOI: 10.3390/polym11010015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 12/19/2022] Open
Abstract
Large DNA molecules have been utilized as a model system to investigate polymer physics. However, DNA visualization via intercalating dyes has generated equivocal results due to dye-induced structural deformation, particularly unwanted unwinding of the double helix. Thus, the contour length increases and the persistence length changes so unpredictably that there has been a controversy. In this paper, we used TAMRA-polypyrrole to stain single DNA molecules. Since this staining did not change the contour length of B-form DNA, we utilized TAMRA-polypyrrole stained DNA as a tool to measure the persistence length by changing the ionic strength. Then, we investigated DNA stretching in nanochannels by varying the ionic strength from 0.06 mM to 47 mM to evaluate several polymer physics theories proposed by Odijk, de Gennes and recent papers to deal with these regimes.
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Affiliation(s)
- Seonghyun Lee
- Department of Chemistry and Integrated Biotechnology, Sogang University, Seoul 04107, Korea.
| | - Yelin Lee
- Department of Chemistry and Integrated Biotechnology, Sogang University, Seoul 04107, Korea.
| | - Yongkyun Kim
- Department of Chemistry and Integrated Biotechnology, Sogang University, Seoul 04107, Korea.
| | - Cong Wang
- Department of Mechanical Engineering, Sogang University, Seoul 04107, Korea.
| | - Jungyul Park
- Department of Mechanical Engineering, Sogang University, Seoul 04107, Korea.
| | - Gun Young Jung
- School of Material Science and Engineering, GIST, Gwangju 61005, Korea.
| | - Yenglong Chen
- Institute of Physics, Academia Sinica and Department of Chemical Engineering, National Tsing-Hua University and Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
| | - Rakwoo Chang
- Department of Chemistry, Kwangwoon University, Seoul 01897, Korea.
| | - Shuji Ikeda
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8501, Japan.
| | - Hiroshi Sugiyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto 606-8501, Japan.
| | - Kyubong Jo
- Department of Chemistry and Integrated Biotechnology, Sogang University, Seoul 04107, Korea.
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34
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Liu J, Wang X, Zhang W. Atomic Force Microscopy Imaging Study of Aligning DNA by Dumbbell-like Au-Fe 3O 4 Magnetic Nanoparticles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:14875-14881. [PMID: 30011364 DOI: 10.1021/acs.langmuir.8b01784] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Studies on nucleic acid structure and interactions between nucleic acid and its binding molecules are of great importance for understanding and controlling many important biological processes. Atomic force microscopy (AFM) imaging is one of the most efficient methods to disclose the DNA structure and binding modes between DNA and DNA-binding molecules. Long-chain DNA tends to form a random coiled structure, which prevents direct AFM imaging observation of the subtle structure formed by DNA itself or protein binding. Aligning DNA from the random coiled state into the extended state is not only important for applications in DNA nanotechnology but also for elucidating the interaction mechanism between DNA and other molecules. Here, we developed an efficient method based on the magnetic field to align long-chain DNA on a silicon surface. We used AFM imaging to study the alignment of DNA at the single-molecule level, showing that DNA can be stretched and highly aligned by the manipulation of magnetic nanoparticles tethered to one end of DNA and that the aligned DNA can be imaged clearly by AFM. In the absence of the magnetic field, the aligned DNA can relax back to a random coiled state upon rinsing. Such alignment and relaxation can be repeated many times, which provides an efficient method for the manipulation of individual DNA molecules and the investigation of DNA and DNA-binding molecule interactions.
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Affiliation(s)
- Jianyu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , People's Republic of China
| | - Xinxin Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , People's Republic of China
| | - Wenke Zhang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry , Jilin University , Changchun 130012 , People's Republic of China
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35
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Capaldi X, Liu Z, Zhang Y, Zeng L, Reyes-Lamothe R, Reisner W. Probing the organization and dynamics of two DNA chains trapped in a nanofluidic cavity. SOFT MATTER 2018; 14:8455-8465. [PMID: 30187055 DOI: 10.1039/c8sm01444b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Here we present a pneumatically-actuated nanofluidic platform that has the capability of dynamically controlling the confinement environment of macromolecules in solution. Using a principle familiar from classic devices based on soft-lithography, the system uses pneumatic pressure to deflect a thin nitride lid into a nanoslit, confining molecules in an array of cavities embedded in the slit. We use this system to quantify the interactions of multiple confined DNA chains, a key problem in polymer physics with important implications for nanofluidic device performance and DNA partitioning/organization in bacteria and the eukaryotes. In particular, we focus on the problem of two-chain confinement, using differential staining of the chains to independently assess the chain conformation, determine the degree of partitioning/mixing in the cavities and assess coupled diffusion of the chain center-of-mass positions. We find that confinement of more than one chain in the cavity can have a drastic impact on the polymer dynamics and conformation.
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Affiliation(s)
- Xavier Capaldi
- Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada.
| | - Zezhou Liu
- Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada.
| | - Yuning Zhang
- Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada.
| | - Lili Zeng
- Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada.
| | - Rodrigo Reyes-Lamothe
- Department of Biology, McGill University, 33649 Sir William Osler, Montreal, Quebec H3G 0B1, Canada
| | - Walter Reisner
- Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A 2T8, Canada.
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36
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Hartmann J, Roy T, Szuttor K, Smiatek J, Holm C, Hardt S. Relaxation of surface-tethered polymers under moderate confinement. SOFT MATTER 2018; 14:7926-7933. [PMID: 30238941 DOI: 10.1039/c8sm01246f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We study the relaxation of surface-tethered polymers in microchannels under moderate confinement (i.e. h ∼ Rg, where h is the channel height and Rg is the radius of gyration of the polymer) by experiments with fluorescence-marked DNA molecules and coupled lattice-Boltzmann/molecular dynamics simulations. The determined scaling exponent suggests that the relaxation is dominated by Zimm-dynamics with significant intra-chain hydrodynamic interactions. The relaxation of the DNA molecules is slower in shallower channels, indicating a pronounced effect of confinement on the longest relaxation time. An experimental correlation is obtained for the longest relaxation time as a function of the molecular contour length and the channel height. Good agreement between the experimental and the simulation results is found.
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Affiliation(s)
- Johannes Hartmann
- Institute for Nano- and Microfluidics, Technische Universität Darmstadt, Darmstadt, Germany.
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37
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Bhandari AB, Reifenberger JG, Chuang HM, Cao H, Dorfman KD. Measuring the wall depletion length of nanoconfined DNA. J Chem Phys 2018; 149:104901. [PMID: 30219022 PMCID: PMC6135644 DOI: 10.1063/1.5040458] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/20/2018] [Indexed: 12/14/2022] Open
Abstract
Efforts to study the polymer physics of DNA confined in nanochannels have been stymied by a lack of consensus regarding its wall depletion length. We have measured this quantity in 38 nm wide, square silicon dioxide nanochannels for five different ionic strengths between 15 mM and 75 mM. Experiments used the Bionano Genomics Irys platform for massively parallel data acquisition, attenuating the effect of the sequence-dependent persistence length and finite-length effects by using nick-labeled E. coli genomic DNA with contour length separations of at least 30 µm (88 325 base pairs) between nick pairs. Over 5 × 106 measurements of the fractional extension were obtained from 39 291 labeled DNA molecules. Analyzing the stretching via Odijk's theory for a strongly confined wormlike chain yielded a linear relationship between the depletion length and the Debye length. This simple linear fit to the experimental data exhibits the same qualitative trend as previously defined analytical models for the depletion length but now quantitatively captures the experimental data.
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Affiliation(s)
- Aditya Bikram Bhandari
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - Jeffrey G Reifenberger
- Bionano Genomics, Inc., 9640 Towne Centre Drive, Suite 100, San Diego, California 92121, USA
| | - Hui-Min Chuang
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
| | - Han Cao
- Bionano Genomics, Inc., 9640 Towne Centre Drive, Suite 100, San Diego, California 92121, USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Ave. SE, Minneapolis, Minnesota 55455, USA
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38
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Zhou Y, Schroeder CM. Dynamically Heterogeneous Relaxation of Entangled Polymer Chains. PHYSICAL REVIEW LETTERS 2018; 120:267801. [PMID: 30004741 DOI: 10.1103/physrevlett.120.267801] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Stress relaxation following deformation of an entangled polymeric liquid is thought to be affected by transient reforming of chain entanglements. In this work, we use single molecule techniques to study the relaxation of individual polymers in the transition regime from unentangled to entangled solutions. Our results reveal the emergence of dynamic heterogeneity underlying polymer relaxation behavior, including distinct molecular subpopulations described by a single-mode and a double-mode exponential relaxation process. The slower double-mode timescale τ_{d,2} is consistent with a characteristic reptation time, whereas the single-mode timescale τ_{s} and the fast double-mode timescale τ_{d,1} are attributed to local regions of transient disentanglement due to deformation.
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Affiliation(s)
- Yuecheng Zhou
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Charles M Schroeder
- Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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39
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Klotz AR, Soh BW, Doyle PS. Motion of Knots in DNA Stretched by Elongational Fields. PHYSICAL REVIEW LETTERS 2018; 120:188003. [PMID: 29775326 DOI: 10.1103/physrevlett.120.188003] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/07/2018] [Indexed: 06/08/2023]
Abstract
Knots in DNA occur in biological systems, serve as a model system for polymer entanglement, and affect the efficacy of modern genomics technologies. We study the motion of complex knots in DNA by stretching molecules with a divergent electric field that provides an elongational force. We demonstrate that the motion of knots is nonisotropic and driven towards the closest end of the molecule. We show for the first time experimentally that knots can go from a mobile to a jammed state by varying an applied strain rate, and that this jamming is reversible. We measure the mobility of knots as a function of strain rate, demonstrating the conditions under which knots can be driven towards the ends of the molecule and untied.
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Affiliation(s)
- Alexander R Klotz
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02142, USA
| | - Beatrice W Soh
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02142, USA
| | - Patrick S Doyle
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02142, USA
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40
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Soh BW, Narsimhan V, Klotz AR, Doyle PS. Knots modify the coil-stretch transition in linear DNA polymers. SOFT MATTER 2018; 14:1689-1698. [PMID: 29423476 DOI: 10.1039/c7sm02195j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We perform single-molecule DNA experiments to investigate the relaxation dynamics of knotted polymers and examine the steady-state behavior of knotted polymers in elongational fields. The occurrence of a knot reduces the relaxation time of a molecule and leads to a shift in the molecule's coil-stretch transition to larger strain rates. We measure chain extension and extension fluctuations as a function of strain rate for unknotted and knotted molecules. The curves for knotted molecules can be collapsed onto the unknotted curves by defining an effective Weissenberg number based on the measured knotted relaxation time in the low extension regime, or a relaxation time based on Rouse/Zimm scaling theories in the high extension regime. Because a knot reduces a molecule's relaxation time, we observe that knot untying near the coil-stretch transition can result in dramatic changes in the molecule's conformation. For example, a knotted molecule at a given strain rate can experience a stretch-coil transition, followed by a coil-stretch transition, after the knot partially or fully unties.
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Affiliation(s)
- Beatrice W Soh
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
| | - Vivek Narsimhan
- Department of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
| | - Alexander R Klotz
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
| | - Patrick S Doyle
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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41
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Gupta D, Bhandari AB, Dorfman KD. Evaluation of Blob Theory for the Diffusion of DNA in Nanochannels. Macromolecules 2018; 51:1748-1755. [PMID: 29599567 DOI: 10.1021/acs.macromol.7b02270] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have measured the diffusivity of λ-DNA molecules in approximately square nanochannels with effective sizes ranging from 117 nm to 260 nm at moderate ionic strength. The experimental results do not agree with the non-draining scaling predicted by blob theory. Rather, the data are consistent with the predictions of previous simulations of the Kirkwood diffusivity of a discrete wormlike chain model, without the need for any fitting parameters.
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Affiliation(s)
- Damini Gupta
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
| | - Aditya Bikram Bhandari
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota - Twin Cities, 421 Washington Ave SE, Minneapolis, Minnesota 55455, USA
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42
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Mai DJ, Saadat A, Khomami B, Schroeder CM. Stretching Dynamics of Single Comb Polymers in Extensional Flow. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02759] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Danielle J. Mai
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Amir Saadat
- Material
Research and Innovation Laboratory,
Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Bamin Khomami
- Material
Research and Innovation Laboratory,
Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Charles M. Schroeder
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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43
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Maschmann A, Masters C, Davison M, Lallman J, Thompson D, Kounovsky-Shafer KL. Determining if DNA Stained with a Cyanine Dye Can Be Digested with Restriction Enzymes. J Vis Exp 2018. [PMID: 29443093 DOI: 10.3791/57141] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Visualization of DNA for fluorescence microscopy utilizes a variety of dyes such as cyanine dyes. These dyes are utilized due to their high affinity and sensitivity for DNA. In order to determine if the DNA molecules are full length after the completion of the experiment, a method is required to determine if the stained molecules are full length by digesting DNA with restriction enzymes. However, stained DNA may inhibit the enzymes, so a method is needed to determine what enzymes one could use for fluorochrome stained DNA. In this method, DNA is stained with a cyanine dye overnight to allow the dye and DNA to equilibrate. Next, stained DNA is digested with a restriction enzyme, loaded into a gel and electrophoresed. The experimental DNA digest bands are compared to an in silico digest to determine the restriction enzyme activity. If there is the same number of bands as expected, then the reaction is complete. More bands than expected indicate partial digestion and less bands indicate incomplete digestion. The advantage of this method is its simplicity and it uses equipment that a scientist would need for a restriction enzyme assay and gel electrophoresis. A limitation of this method is that the enzymes available to most scientists are commercially available enzymes; however, any restriction enzymes could be used.
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Affiliation(s)
| | - Cody Masters
- Department of Chemistry, University of Nebraska - Kearney
| | | | - Joshua Lallman
- Department of Chemistry, University of Nebraska - Kearney
| | - Drew Thompson
- Department of Chemistry, University of Nebraska - Kearney
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44
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Dorfman KD. The Statistical Segment Length of DNA: Opportunities for Biomechanical Modeling in Polymer Physics and Next-Generation Genomics. J Biomech Eng 2018; 140:2653367. [PMID: 28857114 PMCID: PMC5816256 DOI: 10.1115/1.4037790] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 08/16/2017] [Indexed: 12/28/2022]
Abstract
The development of bright bisintercalating dyes for deoxyribonucleic acid (DNA) in the 1990s, most notably YOYO-1, revolutionized the field of polymer physics in the ensuing years. These dyes, in conjunction with modern molecular biology techniques, permit the facile observation of polymer dynamics via fluorescence microscopy and thus direct tests of different theories of polymer dynamics. At the same time, they have played a key role in advancing an emerging next-generation method known as genome mapping in nanochannels. The effect of intercalation on the bending energy of DNA as embodied by a change in its statistical segment length (or, alternatively, its persistence length) has been the subject of significant controversy. The precise value of the statistical segment length is critical for the proper interpretation of polymer physics experiments and controls the phenomena underlying the aforementioned genomics technology. In this perspective, we briefly review the model of DNA as a wormlike chain and a trio of methods (light scattering, optical or magnetic tweezers, and atomic force microscopy (AFM)) that have been used to determine the statistical segment length of DNA. We then outline the disagreement in the literature over the role of bisintercalation on the bending energy of DNA, and how a multiscale biomechanical approach could provide an important model for this scientifically and technologically relevant problem.
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Affiliation(s)
- Kevin D. Dorfman
- Department of Chemical Engineering and
Materials Science,
University of Minnesota—Twin Cities,
421 Washington Ave SE,
Minneapolis, MN 55455
e-mail:
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45
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Kato Y, Sakashita N, Ishida K, Mitsui T. Gate-Voltage-Controlled Threading DNA into Transistor Nanopores. J Phys Chem B 2018; 122:827-833. [PMID: 28893067 DOI: 10.1021/acs.jpcb.7b06932] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a simple method for DNA translocation driven by applying AC voltages, such as square and sawtooth waves, on an embedded thin film as a gate electrode inside of a dielectric nanopore, without applying a conventional bias voltage externally across the pore membrane. Square waveforms on a gate can drive a single DNA molecule into a nanopore, which often returns from the pore, causing an oscillation across the membrane. An optimized sawtooth-like negative voltage pulse on the gate can thread a fraction of a DNA molecule into a pore after a single pulse. This trapped DNA molecule continues to finish its translocation slowly through the pore. The DNA's slow speed was comparable to previous findings of the escaping DNA speed from a nanopore estimated by the Smoluchowski equation with excluded-volume interactions of a long-chain molecule and electrophoresis by extremely low electric fields. This simple scheme, controlling DNA molecules only by gate potential modulation at a nanopore, will provide an additional method to thread, translocate, or oscillate a single biomolecule at a gated nanopore.
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Affiliation(s)
- Yuta Kato
- Aoyama-Gakuin University , Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan
| | - Naoto Sakashita
- Aoyama-Gakuin University , Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan
| | - Kentaro Ishida
- Aoyama-Gakuin University , Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan
| | - Toshiyuki Mitsui
- Aoyama-Gakuin University , Sagamihara Campus L617, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258, Japan
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46
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Abstract
Stretching of DNA in nanoscale confinement allows for several important studies. The genetic contents of the DNA can be visualized on the single DNA molecule level and both the polymer physics of confined DNA and also DNA/protein and other DNA/DNA-binding molecule interactions can be explored. This chapter describes the basic steps to fabricate the nanostructures, perform the experiments and analyze the data.
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47
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Lin TY, Saadat A, Kushwaha A, Shaqfeh ESG. Effect of Length on the Dynamics of Wall Tethered Polymers in Shear Flow. Macromolecules 2017. [DOI: 10.1021/acs.macromol.7b02032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tiras Y. Lin
- Department
of Mechanical Engineering, ‡Department of Chemical Engineering,
and §Institute for
Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Amir Saadat
- Department
of Mechanical Engineering, ‡Department of Chemical Engineering,
and §Institute for
Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Amit Kushwaha
- Department
of Mechanical Engineering, ‡Department of Chemical Engineering,
and §Institute for
Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Eric S. G. Shaqfeh
- Department
of Mechanical Engineering, ‡Department of Chemical Engineering,
and §Institute for
Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
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48
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Weiss LB, Nikoubashman A, Likos CN. Topology-Sensitive Microfluidic Filter for Polymers of Varying Stiffness. ACS Macro Lett 2017; 6:1426-1431. [PMID: 35650806 DOI: 10.1021/acsmacrolett.7b00768] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The separation of polymers based on their size, rigidity, and topology is an essential but also highly challenging task for nanoscience and engineering. Using hybrid molecular dynamics simulations that correctly take into account hydrodynamics, we have designed microfluidic channels for separating linear from ring polymers in dilute solutions. We establish that the transport velocity of the polymers is independent of their topology and rigidity when the channel walls are smooth and repulsive. However, when the walls are decorated with attractive spots arranged on lines parallel to the flow, ring polymers exhibit an order of magnitude higher transport velocity compared to linear chains. The spots induce a homeotropic-like reorientation of ring polymers close to walls leading to a tank treading motion along them, whereas linear chains are immobilized upon adsorption. This mechanism becomes more enhanced with increasing polymer rigidity. The presented technique holds thus promise for reliably separating nanoparticles based on their topology.
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Affiliation(s)
- Lisa B. Weiss
- Faculty
of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Arash Nikoubashman
- Institute
of Physics, Johannes Gutenberg University Mainz, Staudingerweg
7, 55128 Mainz, Germany
| | - Christos N. Likos
- Faculty
of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
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49
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Guha R, Mohajerani F, Mukhopadhyay A, Collins MD, Sen A, Velegol D. Modulation of Spatiotemporal Particle Patterning in Evaporating Droplets: Applications to Diagnostics and Materials Science. ACS APPLIED MATERIALS & INTERFACES 2017; 9:43352-43362. [PMID: 29143530 DOI: 10.1021/acsami.7b13675] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Spatiotemporal particle patterning in evaporating droplets lacks a common design framework. Here, we demonstrate autonomous control of particle distribution in evaporating droplets through the imposition of a salt-induced self-generated electric field as a generalized patterning strategy. Through modeling, a new dimensionless number, termed "capillary-phoresis" (CP) number, arises, which determines the relative contributions of electrokinetic and convective transport to pattern formation, enabling one to accurately predict the mode of particle assembly by controlling the spontaneous electric field and surface potentials. Modulation of the CP number allows the particles to be focused in a specific region in space or distributed evenly. Moreover, starting with a mixture of two different particle types, their relative placement in the ensuing pattern can be controlled, allowing coassemblies of multiple, distinct particle populations. By this approach, hypermethylated DNA, prevalent in cancerous cells, can be qualitatively distinguished from normal DNA of comparable molecular weights. In other examples, we show uniform dispersion of several particle types (polymeric colloids, multiwalled carbon nanotubes, and molecular dyes) on different substrates (metallic Cu, metal oxide, and flexible polymer), as dictated by the CP number. Depending on the particle, the highly uniform distribution leads to surfaces with a lower sheet resistance, as well as superior dye-printed displays.
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Affiliation(s)
- Rajarshi Guha
- Department of Chemical Engineering and ‡Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Farzad Mohajerani
- Department of Chemical Engineering and ‡Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Ahana Mukhopadhyay
- Department of Chemical Engineering and ‡Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Matthew D Collins
- Department of Chemical Engineering and ‡Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Ayusman Sen
- Department of Chemical Engineering and ‡Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Darrell Velegol
- Department of Chemical Engineering and ‡Department of Chemistry, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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50
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Chuang HM, Reifenberger JG, Cao H, Dorfman KD. Sequence-Dependent Persistence Length of Long DNA. PHYSICAL REVIEW LETTERS 2017; 119:227802. [PMID: 29286779 PMCID: PMC5839665 DOI: 10.1103/physrevlett.119.227802] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Indexed: 05/04/2023]
Abstract
Using a high-throughput genome-mapping approach, we obtained circa 50 million measurements of the extension of internal human DNA segments in a 41 nm×41 nm nanochannel. The underlying DNA sequences, obtained by mapping to the reference human genome, are 2.5-393 kilobase pairs long and contain percent GC contents between 32.5% and 60%. Using Odijk's theory for a channel-confined wormlike chain, these data reveal that the DNA persistence length increases by almost 20% as the percent GC content increases. The increased persistence length is rationalized by a model, containing no adjustable parameters, that treats the DNA as a statistical terpolymer with a sequence-dependent intrinsic persistence length and a sequence-independent electrostatic persistence length.
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Affiliation(s)
- Hui-Min Chuang
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
| | | | - Han Cao
- BioNano Genomics, 9640 Towne Centre Drive, Suite 100, San Diego, California 92121, USA
| | - Kevin D Dorfman
- Department of Chemical Engineering and Materials Science, University of Minnesota-Twin Cities, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA
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