1
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Nussberger S, Ghosh R, Wang S. New insights into the structure and dynamics of the TOM complex in mitochondria. Biochem Soc Trans 2024; 52:911-922. [PMID: 38629718 PMCID: PMC11088910 DOI: 10.1042/bst20231236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/21/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024]
Abstract
To date, there is no general physical model of the mechanism by which unfolded polypeptide chains with different properties are imported into the mitochondria. At the molecular level, it is still unclear how transit polypeptides approach, are captured by the protein translocation machinery in the outer mitochondrial membrane, and how they subsequently cross the entropic barrier of a protein translocation pore to enter the intermembrane space. This deficiency has been due to the lack of detailed structural and dynamic information about the membrane pores. In this review, we focus on the recently determined sub-nanometer cryo-EM structures and our current knowledge of the dynamics of the mitochondrial two-pore outer membrane protein translocation machinery (TOM core complex), which provide a starting point for addressing the above questions. Of particular interest are recent discoveries showing that the TOM core complex can act as a mechanosensor, where the pores close as a result of interaction with membrane-proximal structures. We highlight unusual and new correlations between the structural elements of the TOM complexes and their dynamic behavior in the membrane environment.
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Affiliation(s)
- Stephan Nussberger
- Department of Biophysics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Robin Ghosh
- Department of Bioenergetics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
| | - Shuo Wang
- Department of Biophysics, Institute of Biomaterials and Biomolecular Systems, University of Stuttgart, Stuttgart, Germany
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2
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Rostovtseva TK, Weinrich M, Jacobs D, Rosencrans WM, Bezrukov SM. Dimeric Tubulin Modifies Mechanical Properties of Lipid Bilayer, as Probed Using Gramicidin A Channel. Int J Mol Sci 2024; 25:2204. [PMID: 38396879 PMCID: PMC10889239 DOI: 10.3390/ijms25042204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 01/31/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Using the gramicidin A channel as a molecular probe, we show that tubulin binding to planar lipid membranes changes the channel kinetics-seen as an increase in the lifetime of the channel dimer-and thus points towards modification of the membrane's mechanical properties. The effect is more pronounced in the presence of non-lamellar lipids in the lipid mixture used for membrane formation. To interpret these findings, we propose that tubulin binding redistributes the lateral pressure of lipid packing along the membrane depth, making it closer to the profile expected for lamellar lipids. This redistribution happens because tubulin perturbs the lipid headgroup spacing to reach the membrane's hydrophobic core via its amphiphilic α-helical domain. Specifically, it increases the forces of repulsion between the lipid headgroups and reduces such forces in the hydrophobic region. We suggest that the effect is reciprocal, meaning that alterations in lipid bilayer mechanics caused by membrane remodeling during cell proliferation in disease and development may also modulate tubulin membrane binding, thus exerting regulatory functions. One of those functions includes the regulation of protein-protein interactions at the membrane surface, as exemplified by VDAC complexation with tubulin.
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Affiliation(s)
- Tatiana K. Rostovtseva
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
| | - Michael Weinrich
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Daniel Jacobs
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
| | - William M. Rosencrans
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
- Department of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Sergey M. Bezrukov
- Program in Physical Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA (S.M.B.)
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3
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Bandara YMNDY, Karawdeniya BI, Dutt S, Kluth P, Tricoli A. Nanopore Fabrication Made Easy: A Portable, Affordable Microcontroller-Assisted Approach for Tailored Pore Formation via Controlled Breakdown. Anal Chem 2024; 96:2124-2134. [PMID: 38277343 DOI: 10.1021/acs.analchem.3c04860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
With growing interest in solid-state nanopore sensing─a single-molecule technique capable of profiling a host of analyte classes─establishing facile and scalable approaches for fabricating molecular-size pores is becoming increasingly important. The introduction of nanopore fabrication by controlled breakdown (CBD) has transformed the economics and accessibility of nanopore fabrication. Here, we introduce the design of an Arduino-based, portable USB-powered CBD device, with an estimated cost of <150 USD, which is ≈10-100× cheaper than most commercial solutions, capable of fabricating single nanopores conducive for single molecule sensing experiments. We demonstrate the facile fabrication of 60 tailored nanopores (∼2.6-12.6 nm) with ∼80% of the pores within 1 nm of the target diameter. Selected pores were then tested with double-stranded DNA, the canonical molecular ruler, demonstrating their performance for single-molecule sensing applications. The device is constructed with off-the-shelf readily available components and controlled using a highly customizable MATLAB application, which has capabilities encompassing pore fabrication, pore enlargement, and current-voltage acquisition for pore size estimation. When combined with a portable amplifier, this device also provides a fully portable sensing platform, an important step toward portable solid-state nanopore sensing applications.
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Affiliation(s)
- Y M Nuwan D Y Bandara
- Nanotechnology Research Laboratory, Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Buddini I Karawdeniya
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Shankar Dutt
- Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Patrick Kluth
- Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT 2601, Australia
| | - Antonio Tricoli
- Nanotechnology Research Laboratory, Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
- Nanotechnology Research Laboratory, School of Biomedical Engineering, Faculty of Engineering, University of Sydney, NSW 2008, Australia
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4
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Upadhyay G, Kapri R, Chaudhuri A. Gain reversal in the translocation dynamics of a semiflexible polymer through a flickering pore. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:185101. [PMID: 38262064 DOI: 10.1088/1361-648x/ad21a9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/23/2024] [Indexed: 01/25/2024]
Abstract
We study the driven translocation of a semiflexible polymer through an attractive extended pore with a periodically oscillating width. Similar to its flexible counterpart, a stiff polymer translocates through an oscillating pore more quickly than a static pore whose width is equal to the oscillating pore's mean width. This efficiency quantified as a gain in the translocation time, highlights a considerable dependence of the translocation dynamics on the stiffness of the polymer and the attractive nature of the pore. The gain characteristics for various polymer stiffness exhibit a trend reversal when the stickiness of the pore is changed. The gain reduces with increasing stiffness for a lower attractive strength of the pore, whereas it increases with increasing stiffness for higher attractive strengths. Such a dependence leads to the possibility of a high degree of robust selectivity in the translocation process.
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Affiliation(s)
- Gokul Upadhyay
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli 140306, India
| | - Rajeev Kapri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli 140306, India
| | - Abhishek Chaudhuri
- Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, Knowledge City, S. A. S. Nagar, Manauli 140306, India
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5
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Burden DL, Meyer JJ, Michael RD, Anderson SC, Burden HM, Peña SM, Leong-Fern KJ, Van Ye LA, Meyer EC, Keranen-Burden LM. Confirming Silent Translocation through Nanopores with Simultaneous Single-Molecule Fluorescence and Single-Channel Electrical Recordings. Anal Chem 2023; 95:18020-18028. [PMID: 37991877 PMCID: PMC10719886 DOI: 10.1021/acs.analchem.3c02329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 11/07/2023] [Accepted: 11/08/2023] [Indexed: 11/24/2023]
Abstract
Most of what is known concerning the luminal passage of materials through nanopores arises from electrical measurements. Whether nanopores are biological, solid-state, synthetic, hybrid, glass-capillary-based, or protein ion channels in cells and tissues, characteristic signatures embedded in the flow of ionic current are foundational to understanding functional behavior. In contrast, this work describes passage through a nanopore that occurs without producing an electrical signature. We refer to the phenomenon as "silent translocation." By definition, silent translocations are invisible to the standard tools of electrophysiology and fundamentally require a simultaneous ancillary measurement technique for positive identification. As a result, this phenomenon has been largely unexplored in the literature. Here, we report on a derivative of Cyanine 5 (sCy5a) that passes through the α-hemolysin (αHL) nanopore silently. Simultaneously acquired single-molecule fluorescence and single-channel electrical recordings from bilayers formed over a closed microcavity demonstrate that translocation does indeed take place, albeit infrequently. We report observations of silent translocation as a function of time, dye concentration, and nanopore population in the bilayer. Lastly, measurement of the translocation rate as a function of applied potential permits estimation of an effective energy barrier for transport through the pore as well as the effective charge on the dye, all in the absence of an information-containing electrical signature.
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Affiliation(s)
- Daniel L. Burden
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Joshua J. Meyer
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Richard D. Michael
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Sophie C. Anderson
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Hannah M. Burden
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Sophia M. Peña
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | | | - Lily Anne Van Ye
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
| | - Elizabeth C. Meyer
- Chemistry Department, Wheaton College, Wheaton, Illinois 60187, United States
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6
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Huang Y, Liu L, Luo C, Liu W, Lou X, Jiang L, Xia F. Solid-state nanochannels for bio-marker analysis. Chem Soc Rev 2023; 52:6270-6293. [PMID: 37581902 DOI: 10.1039/d2cs00865c] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
Bio-markers, such as ions, small molecules, nucleic acids, peptides, proteins and cells, participate in the construction of living organisms and play important roles in biological processes. It is of great significance to accurately detect these bio-markers for studying their basic functions, the development of molecular diagnosis and to better understand life processes. Solid-state nanochannel-based sensing systems have been demonstrated for the detection of bio-markers, due to their rapid, label-free and high-throughput screening, with high sensitivity and specificity. Generally, studies on solid-state nanochannels have focused on probes on the inner-wall (PIW), ignoring probes on the outer-surface (POS). As a result, the direct detection of cells is difficult to realize by these inner-wall focused nanochannels. Moreover, the sensitivity for detecting ions, small molecules, nucleic acids, peptides and proteins requires further improvement. Recent research has focused on artificial solid-state nanochannels with POS, which have demonstrated the ability to independently regulate ion transport. This design not only contributes to the in situ detection of large analytes, such as cells, but also provides promising opportunities for ultra-high sensitivity detection with a clear mechanism. In this tutorial review, we present an overview of the detection principle used for solid-state nanochannels, inner-wall focused nanochannels and outer-surface focused nanochannels. Furthermore, we discuss the remaining challenges faced by current nanochannel technologies and provide insights into their prospects.
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Affiliation(s)
- Yu Huang
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
- Zhejiang Institute, China University of Geosciences, Hangzhou, 311305, China
| | - Lingxiao Liu
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
| | - Cihui Luo
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
| | - Wei Liu
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210046, China
| | - Xiaoding Lou
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
| | - Lei Jiang
- Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of the Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Fan Xia
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China.
- Zhejiang Institute, China University of Geosciences, Hangzhou, 311305, China
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7
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Wang Z, Ziolek RM, Tsige M. Constraints on Knot Insertion, Not Internal Jamming, Control Polycatenane Translocation Dynamics through Crystalline Pores. Macromolecules 2023; 56:3238-3245. [PMID: 37128623 PMCID: PMC10141125 DOI: 10.1021/acs.macromol.2c02565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/15/2023] [Indexed: 05/03/2023]
Abstract
The translocation of polymers through pores and channels is an archetypal process in biology and is widely studied and exploited for applications in bio- and nanotechnology. In recent times, the translocation of polymers of various different topologies has been studied both experimentally and by computer simulation. However, in some cases, a clear understanding of the precise mechanisms that drive their translocation dynamics can be challenging to derive. Experimental methods are able to provide statistical details of polymer translocation, but computer simulations are uniquely placed to uncover a finer level of mechanistic understanding. In this work, we use high-throughput molecular simulations to reveal the importance that knot insertion rates play in controlling translocation dynamics in the small pore limit, where unexpected nonpower law behavior emerges. This work both provides new predictive understanding of polycatenane translocation and shows the importance of carefully considering the role of the definition of translocation itself.
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Affiliation(s)
- Zifeng Wang
- School
of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325-3909, United States
| | - Robert M. Ziolek
- Biological
Physics and Soft Matter Group, Department of Physics, King’s College London, London WC2R 2LS, United Kingdom
| | - Mesfin Tsige
- School
of Polymer Science and Polymer Engineering, The University of Akron, Akron, Ohio 44325-3909, United States
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8
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Singh SL, Chauhan K, Bharadwaj AS, Kishore V, Laux P, Luch A, Singh AV. Polymer Translocation and Nanopore Sequencing: A Review of Advances and Challenges. Int J Mol Sci 2023; 24:6153. [PMID: 37047125 PMCID: PMC10094227 DOI: 10.3390/ijms24076153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/01/2023] [Accepted: 02/28/2023] [Indexed: 03/31/2023] Open
Abstract
Various biological processes involve the translocation of macromolecules across nanopores; these pores are basically protein channels embedded in membranes. Understanding the mechanism of translocation is crucial to a range of technological applications, including DNA sequencing, single molecule detection, and controlled drug delivery. In this spirit, numerous efforts have been made to develop polymer translocation-based sequencing devices, these efforts include findings and insights from theoretical modeling, simulations, and experimental studies. As much as the past and ongoing studies have added to the knowledge, the practical realization of low-cost, high-throughput sequencing devices, however, has still not been realized. There are challenges, the foremost of which is controlling the speed of translocation at the single monomer level, which remain to be addressed in order to use polymer translocation-based methods for sensing applications. In this article, we review the recent studies aimed at developing control over the dynamics of polymer translocation through nanopores.
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Affiliation(s)
- Swarn Lata Singh
- Department of Physics, Mahila Mahavidyalaya (MMV), Banaras Hindu University, Varanasi 221005, UP, India
| | - Keerti Chauhan
- Department of Physics, Banaras Hindu University, Varanasi 221005, UP, India
| | - Atul S. Bharadwaj
- Department of Physics, CMP Degree College, University of Allahabad, Prayagraj 211002, UP, India
| | - Vimal Kishore
- Department of Physics, Banaras Hindu University, Varanasi 221005, UP, India
| | - Peter Laux
- Department of Chemical and Product Safety, German Federal Institute of Risk Assessment (BfR) Maxdohrnstrasse 8-10, 10589 Berlin, Germany
| | - Andreas Luch
- Department of Chemical and Product Safety, German Federal Institute of Risk Assessment (BfR) Maxdohrnstrasse 8-10, 10589 Berlin, Germany
| | - Ajay Vikram Singh
- Department of Chemical and Product Safety, German Federal Institute of Risk Assessment (BfR) Maxdohrnstrasse 8-10, 10589 Berlin, Germany
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9
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Hu G, Yan H, Xi G, Gao Z, Wu Z, Lu Z, Tu J. Nanopore sensors for single molecular protein detection: Research progress based on computer simulations. IET Nanobiotechnol 2023; 17:257-268. [PMID: 36924083 DOI: 10.1049/nbt2.12124] [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: 12/29/2022] [Revised: 02/20/2023] [Accepted: 02/27/2023] [Indexed: 03/18/2023] Open
Abstract
As biological macromolecules, proteins are involved in important cellular functions ranging from DNA replication and biosynthesis to metabolic signalling and environmental sensing. Protein sequencing can help understand the relationship between protein function and structure, and provide key information for disease diagnosis and new drug design. Nanopore sensors are a novel technology to achieve the goal of label-free and high-throughput protein sequencing. In recent years, nanopore-based biosensors have been widely used in the detection and analysis of biomolecules such as DNA, RNA, and proteins. At the same time, computer simulations can describe the transport of proteins through nanopores at the atomic level. This paper reviews the applications of nanopore sensors in protein sequencing over the past decade and the solutions to key problems from a computer simulation perspective, with the aim of pointing the way to the future of nanopore protein sequencing.
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Affiliation(s)
- Gang Hu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Han Yan
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Guohao Xi
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Zhuwei Gao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Ziqing Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Zuhong Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Jing Tu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
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10
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Chau C, Marcuccio F, Soulias D, Edwards MA, Tuplin A, Radford SE, Hewitt E, Actis P. Probing RNA Conformations Using a Polymer-Electrolyte Solid-State Nanopore. ACS NANO 2022; 16:20075-20085. [PMID: 36279181 PMCID: PMC9798860 DOI: 10.1021/acsnano.2c08312] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nanopore systems have emerged as a leading platform for the analysis of biomolecular complexes with single-molecule resolution. The conformation of biomolecules, such as RNA, is highly dependent on the electrolyte composition, but solid-state nanopore systems often require high salt concentration to operate, precluding analysis of macromolecular conformations under physiologically relevant conditions. Here, we report the implementation of a polymer-electrolyte solid-state nanopore system based on alkali metal halide salts dissolved in 50% w/v poly(ethylene) glycol (PEG) to augment the performance of our system. We show that polymer-electrolyte bath governs the translocation dynamics of the analyte which correlates with the physical properties of the salt used in the bath. This allowed us to identify CsBr as the optimal salt to complement PEG to generate the largest signal enhancement. Harnessing the effects of the polymer-electrolyte, we probed the conformations of the Chikungunya virus (CHIKV) RNA genome fragments under physiologically relevant conditions. Our system was able to fingerprint CHIKV RNA fragments ranging from ∼300 to ∼2000 nt length and subsequently distinguish conformations between the co-transcriptionally folded and the natively refolded ∼2000 nt CHIKV RNA. We envision that the polymer-electrolyte solid-state nanopore system will further enable structural and conformational analyses of individual biomolecules under physiologically relevant conditions.
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Affiliation(s)
- Chalmers Chau
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
| | - Fabio Marcuccio
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
| | - Dimitrios Soulias
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
| | - Martin Andrew Edwards
- Department
of Chemistry & Biochemistry, University
of Arkansas, Fayetteville, Arkansas 72701, United States
| | - Andrew Tuplin
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Sheena E. Radford
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Eric Hewitt
- School
of Molecular and Cellular Biology and Astbury Centre for Structural
Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
| | - Paolo Actis
- School
of Electronic and Electrical Engineering and Pollard Institute, University of Leeds, Leeds LS2 9JT, U.K.
- Bragg
Centre for Materials Research, University
of Leeds, Leeds LS2 9JT, U.K.
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11
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Russell W, Lin CY, Siwy ZS. Gating with Charge Inversion to Control Ionic Transport in Nanopores. ACS APPLIED NANO MATERIALS 2022; 5:17682-17692. [PMID: 36583126 PMCID: PMC9791654 DOI: 10.1021/acsanm.2c03573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
Multivalent ions modify the properties of the solid/liquid interfaces, and in some cases, they can even invert the polarity of surface charge, having large consequences for separation processes based on charge. The so-called charge inversion is observed as a switch from negative surface charge in monovalent salts, e.g., KCl, to effective positive surface charge in multivalent salts that is possible through a strong accumulation and correlation of the multivalent ions at the surface. It is not known yet, however, whether the density of the positive charge induced by charge inversion depends on the pore opening diameter, especially in extreme nanoconfinement. Here, we probe how the effective surface charge induced by charge inversion is influenced by the pore opening diameter using a series of nanopores with an opening between 4 and 25 nm placed in contact with trivalent chromium ions in tris(ethylenediamine)chromium(III) sulfate at different concentrations. Our results suggest that the effective positive charge density can indeed be modified by nanoconfinement to the extent that is dependent on the pore diameter, salt concentration, and applied voltage. In addition, the correlated ions can increase the transmembrane current in nanopores with an opening diameter down to 10 nm and cause a significant blockage of the current for narrower pores. The results provide guidelines to control ionic transport at the nanoscale with multivalent ions and demonstrate that in the same experimental conditions, differently sized pores in the same porous material can feature different surface charge density and possibly ion selectivity.
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Affiliation(s)
- Wilfred
S. Russell
- Department
of Chemistry, University of California, Irvine, California 92697, United States
| | - Chih-Yuan Lin
- Department
of Physics and Astronomy, University of
California, Irvine, California 92697, United States
| | - Zuzanna S. Siwy
- Department
of Chemistry, University of California, Irvine, California 92697, United States
- Department
of Physics and Astronomy, University of
California, Irvine, California 92697, United States
- Biomedical
Engineering, University of California, Irvine, California 92697, United States
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12
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Hu G, Xi G, Yan H, Gao Z, Wu Z, Lu Z, Tu J. A molecular dynamics investigation of Taq DNA polymerase and its complex with a DNA substrate using a solid-state nanopore biosensor. Phys Chem Chem Phys 2022; 24:29977-29987. [PMID: 36472131 DOI: 10.1039/d2cp03993a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Proteins have a small volume difference by the diversity of amino acids, which make protein detection and identification a great challenge. Solid-state nanopore as label-free biosensors has attracted attention with high sensitivity. In this work, we investigated the Taq DNA polymerase before and after combining it with a DNA substrate on a solid-state nanopore through molecular dynamics. In simulation, we analyzed the contribution source of nanopore current blockage. In addition to considering the traditional physical exclusion volume model, the non-covalent interaction between the protein molecules and the pore wall also showed to affect the current blockage in the nanopore. When choosing pores of comparable size to protein molecules, the two states of Taq DNA polymerase produce differentiated non-covalent interactions with the pore wall, which enhanced the amplitude difference in current blockage. As a result, the two DNA polymerases can be distinguished through the distinct current blockage. However, when applying additional pulling force or increasing the pore size of the nanopore, the differences between the current blockages are not significant enough to distinguish. The introduction of the non-covalent interaction makes it clear to understand the current blockage differences, which guide the mechanism between molecules with similar structures or volumes.
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Affiliation(s)
- Gang Hu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Guohao Xi
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Han Yan
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Zhuwei Gao
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Ziqing Wu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Zuhong Lu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
| | - Jing Tu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
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13
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Biophysical quantification of unitary solute and solvent permeabilities to enable translation to membrane science. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.121308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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14
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Sharma A, Kapri R, Chaudhuri A. Driven translocation of a semiflexible polymer through a conical channel in the presence of attractive surface interactions. Sci Rep 2022; 12:19081. [PMID: 36351960 PMCID: PMC9646819 DOI: 10.1038/s41598-022-21845-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 10/04/2022] [Indexed: 11/11/2022] Open
Abstract
We study the translocation of a semiflexible polymer through a conical channel with attractive surface interactions and a driving force which varies spatially inside the channel. Using the results of the translocation dynamics of a flexible polymer through an extended channel as control, we first show that the asymmetric shape of the channel gives rise to non-monotonic features in the total translocation time as a function of the apex angle of the channel. The waiting time distributions of individual monomer beads inside the channel show unique features strongly dependent on the driving force and the surface interactions. Polymer stiffness results in longer translocation times for all angles of the channel. Further, non-monotonic features in the translocation time as a function of the channel angle changes substantially as the polymer becomes stiffer, which is reflected in the changing features of the waiting time distributions. We construct a free energy description of the system incorporating entropic and energetic contributions in the low force regime to explain the simulation results.
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Affiliation(s)
- Andri Sharma
- grid.458435.b0000 0004 0406 1521Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S. A. S. Nagar, Mohali, 140306 Punjab India
| | - Rajeev Kapri
- grid.458435.b0000 0004 0406 1521Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S. A. S. Nagar, Mohali, 140306 Punjab India
| | - Abhishek Chaudhuri
- grid.458435.b0000 0004 0406 1521Department of Physical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, S. A. S. Nagar, Mohali, 140306 Punjab India
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15
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Wu Y, Gooding JJ. The application of single molecule nanopore sensing for quantitative analysis. Chem Soc Rev 2022; 51:3862-3885. [PMID: 35506519 DOI: 10.1039/d1cs00988e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Nanopore-based sensors typically work by monitoring transient pulses in conductance via current-time traces as molecules translocate through the nanopore. The unique property of being able to monitor single molecules gives nanopore sensors the potential as quantitative sensors based on the counting of single molecules. This review provides an overview of the concepts and fabrication of nanopore sensors as well as nanopore sensing with a view toward using nanopore sensors for quantitative analysis. We first introduce the classification of nanopores and highlight their applications in molecular identification with some pioneering studies. The review then shifts focus to recent strategies to extend nanopore sensors to devices that can rapidly and accurately quantify the amount of an analyte of interest. Finally, future prospects are provided and briefly discussed. The aim of this review is to aid in understanding recent advances, challenges, and prospects for nanopore sensors for quantitative analysis.
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Affiliation(s)
- Yanfang Wu
- School of Chemistry and Australian Centre for NanoMedicine, The University of New South Wales, Sydney, New South Wales 2052, Australia.
| | - J Justin Gooding
- School of Chemistry and Australian Centre for NanoMedicine, The University of New South Wales, Sydney, New South Wales 2052, Australia.
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16
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Brady MM, Meyer AS. Cataloguing the proteome: Current developments in single-molecule protein sequencing. BIOPHYSICS REVIEWS 2022; 3:011304. [PMID: 38505228 PMCID: PMC10903494 DOI: 10.1063/5.0065509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 01/13/2022] [Indexed: 03/21/2024]
Abstract
The cellular proteome is complex and dynamic, with proteins playing a critical role in cell-level biological processes that contribute to homeostasis, stimuli response, and disease pathology, among others. As such, protein analysis and characterization are of extreme importance in both research and clinical settings. In the last few decades, most proteomics analysis has relied on mass spectrometry, affinity reagents, or some combination thereof. However, these techniques are limited by their requirements for large sample amounts, low resolution, and insufficient dynamic range, making them largely insufficient for the characterization of proteins in low-abundance or single-cell proteomic analysis. Despite unique technical challenges, several single-molecule protein sequencing (SMPS) technologies have been proposed in recent years to address these issues. In this review, we outline several approaches to SMPS technologies and discuss their advantages, limitations, and potential contributions toward an accurate, sensitive, and high-throughput platform.
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Affiliation(s)
- Morgan M. Brady
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
| | - Anne S. Meyer
- Department of Biology, University of Rochester, Rochester, New York 14627, USA
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17
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Choudhary A, Maffeo C, Aksimentiev A. Multi-resolution simulation of DNA transport through large synthetic nanostructures. Phys Chem Chem Phys 2022; 24:2706-2716. [PMID: 35050282 PMCID: PMC8855663 DOI: 10.1039/d1cp04589j] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Modeling and simulation has become an invaluable partner in development of nanopore sensing systems. The key advantage of the nanopore sensing method - the ability to rapidly detect individual biomolecules as a transient reduction of the ionic current flowing through the nanopore - is also its key deficiency, as the current signal itself rarely provides direct information about the chemical structure of the biomolecule. Complementing experimental calibration of the nanopore sensor readout, coarse-grained and all-atom molecular dynamics simulations have been used extensively to characterize the nanopore translocation process and to connect the microscopic events taking place inside the nanopore to the experimentally measured ionic current blockades. Traditional coarse-grained simulations, however, lack the precision needed to predict ionic current blockades with atomic resolution whereas traditional all-atom simulations are limited by the length and time scales amenable to the method. Here, we describe a multi-resolution framework for modeling electric field-driven passage of DNA molecules and nanostructures through to-scale models of synthetic nanopore systems. We illustrate the method by simulating translocation of double-stranded DNA through a solid-state nanopore and a micron-scale slit, capture and translocation of single-stranded DNA in a double nanopore system, and modeling ionic current readout from a DNA origami nanostructure passage through a nanocapillary. We expect our multi-resolution simulation framework to aid development of the nanopore field by providing accurate, to-scale modeling capability to research laboratories that do not have access to leadership supercomputer facilities.
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Affiliation(s)
- Adnan Choudhary
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
| | - Christopher Maffeo
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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18
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Liu W, Nestorovich EM. Probing Protein Nanopores with Poly(ethylene glycol)s. Proteomics 2022; 22:e2100055. [PMID: 35030301 DOI: 10.1002/pmic.202100055] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 11/16/2021] [Accepted: 01/10/2022] [Indexed: 11/08/2022]
Abstract
Neutral water-soluble poly(ethylene glycol)s (PEGs) have been extensively explored in protein nanopore research for the past several decades. The principal use of PEGs is to investigate the membrane protein ion channel physical characteristics and transport properties. In addition, protein nanopores are used to study polymer-protein interactions and polymer physicochemical properties. In this review, we focus on the biophysical studies on probing protein ion channels with PEGs, specifically on nanopore sizing by PEG partitioning. We discuss the fluctuation analysis of ion channel currents in response to the PEGs moving within their confined geometries. The advantages, limitations, and recent developments of the approach are also addressed. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Wenxing Liu
- Department of Biology, The Catholic University of America, 620 Michigan Ave, Washington, DC, 20064, USA
| | - Ekaterina M Nestorovich
- Department of Biology, The Catholic University of America, 620 Michigan Ave, Washington, DC, 20064, USA
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19
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Knowles SF, Weckman NE, Lim VJY, Bonthuis DJ, Keyser UF, Thorneywork AL. Current Fluctuations in Nanopores Reveal the Polymer-Wall Adsorption Potential. PHYSICAL REVIEW LETTERS 2021; 127:137801. [PMID: 34623825 DOI: 10.1103/physrevlett.127.137801] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 08/19/2021] [Indexed: 06/13/2023]
Abstract
Modification of surface properties by polymer adsorption is a widely used technique to tune interactions in molecular experiments such as nanopore sensing. Here, we investigate how the ionic current noise through solid-state nanopores reflects the adsorption of short, neutral polymers to the pore surface. The power spectral density of the noise shows a characteristic change upon adsorption of polymer, the magnitude of which is strongly dependent on both polymer length and salt concentration. In particular, for short polymers at low salt concentrations no change is observed, despite the verification of comparable adsorption in these systems using quartz crystal microbalance measurements. We propose that the characteristic noise is generated by the movement of polymers on and off the surface and perform simulations to assess the feasibility of this model. Excellent agreement with experimental data is obtained using physically motivated simulation parameters, providing deep insight into the shape of the adsorption potential and underlying processes. This paves the way toward using noise spectral analysis for in situ characterization of functionalized nanopores.
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Affiliation(s)
- Stuart F Knowles
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Nicole E Weckman
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Vincent J Y Lim
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Douwe J Bonthuis
- Institute of Theoretical and Computational Physics, Graz University of Technology, 8010 Graz, Austria
| | - Ulrich F Keyser
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Alice L Thorneywork
- Cavendish Laboratory, Department of Physics, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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20
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Hoogerheide DP, Rostovtseva TK, Bezrukov SM. Exploring lipid-dependent conformations of membrane-bound α-synuclein with the VDAC nanopore. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183643. [PMID: 33971161 PMCID: PMC8255272 DOI: 10.1016/j.bbamem.2021.183643] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/21/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023]
Abstract
Regulation of VDAC by α-synuclein (αSyn) is a rich and instructive example of protein-protein interactions catalyzed by a lipid membrane surface. αSyn, a peripheral membrane protein involved in Parkinson's disease pathology, is known to bind to membranes in a transient manner. αSyn's negatively charged C-terminal domain is then available to be electromechanically trapped by the VDAC β-barrel, a process that is observed in vitro as the reversible reduction of ion flow through a single voltage-biased VDAC nanopore. Binding of αSyn to the lipid bilayer is a prerequisite of the channel-protein interaction; surprisingly, however, we find that the strength of αSyn binding to the membrane does not correlate in any simple way with its efficiency of blocking VDAC, suggesting that the lipid-dependent conformations of the membrane-bound αSyn control the interaction. Quantitative models of the free energy landscape governing the capture and release processes allow us to discriminate between several αSyn (sub-) conformations on the membrane surface. These results, combined with known structural features of αSyn on anionic lipid membranes, point to a model in which the lipid composition determines the fraction of αSyn molecules for which the charged C terminal domain is constrained to be close, but not tightly bound, to the membrane surface and thus readily captured by the VDAC nanopore. We speculate that changes in the mitochondrial membrane lipid composition may be key regulators of the αSyn-VDAC interaction and consequently of VDAC-facilitated transport of ions and metabolites in and out of mitochondria and, i.e. mitochondrial metabolism.
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Affiliation(s)
- David P Hoogerheide
- Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Tatiana K Rostovtseva
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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21
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Robertson JW, Ghimire M, Reiner JE. Nanopore sensing: A physical-chemical approach. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183644. [PMID: 33989531 PMCID: PMC9793329 DOI: 10.1016/j.bbamem.2021.183644] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 12/30/2022]
Abstract
Protein nanopores have emerged as an important class of sensors for the understanding of biophysical processes, such as molecular transport across membranes, and for the detection and characterization of biopolymers. Here, we trace the development of these sensors from the Coulter counter and squid axon studies to the modern applications including exquisite detection of small volume changes and molecular reactions at the single molecule (or reactant) scale. This review focuses on the chemistry of biological pores, and how that influences the physical chemistry of molecular detection.
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Affiliation(s)
- Joseph W.F. Robertson
- Biophysical and Biomedical Measurement Group, Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg MD. 20899, correspondence to:
| | - Madhav Ghimire
- Department of Physics, Virginia Commonwealth University, Richmond, VA
| | - Joseph E. Reiner
- Department of Physics, Virginia Commonwealth University, Richmond, VA
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22
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Chen X, Chen J, Zhuo BY, Yang X, Luo MB. Simulation study for the pulling translocation of a polymer globule. Polym J 2021. [DOI: 10.1038/s41428-021-00502-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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23
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Yamini G, Kanchi S, Kalu N, Momben Abolfath S, Leppla SH, Ayappa KG, Maiti PK, Nestorovich EM. Hydrophobic Gating and 1/ f Noise of the Anthrax Toxin Channel. J Phys Chem B 2021; 125:5466-5478. [PMID: 34015215 DOI: 10.1021/acs.jpcb.0c10490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
"Pink" or 1/f noise is a natural phenomenon omnipresent in physics, economics, astrophysics, biology, and even music and languages. In electrophysiology, the stochastic activity of a number of biological ion channels and artificial nanopores could be characterized by current noise with a 1/f power spectral density. In the anthrax toxin channel (PA63), it appears as fast voltage-independent current interruptions between conducting and nonconducting states. This behavior hampers potential development of PA63 as an ion-channel biosensor. On the bright side, the PA63 flickering represents a mesmerizing phenomenon to investigate. Notably, similar 1/f fluctuations are observed in the channel-forming components of clostridial binary C2 and iota toxins, which share functional and structural similarities with the anthrax toxin channel. Similar to PA63, they are evolved to translocate the enzymatic components of the toxins into the cytosol. Here, using high-resolution single-channel lipid bilayer experiments and all-atom molecular dynamic simulations, we suggest that the 1/f noise in PA63 occurs as a result of "hydrophobic gating" at the ϕ-clamp region, the phenomenon earlier observed in several water-filled channels "fastened" inside by the hydrophobic belts. The ϕ-clamp is a narrow "hydrophobic ring" in the PA63 lumen formed by seven or eight phenylalanine residues at position 427, conserved in the C2 and iota toxin channels, which catalyzes protein translocation. Notably, the 1/f noise remains undetected in the F427A PA63 mutant. This finding can elucidate the functional purpose of 1/f noise and its possible role in the transport of the enzymatic components of binary toxins.
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Affiliation(s)
- Goli Yamini
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
| | - Subbarao Kanchi
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru 560012, India.,Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India
| | - Nnanya Kalu
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
| | - Sanaz Momben Abolfath
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
| | - Stephen H Leppla
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru 560012, India
| | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru 560012, India
| | - Ekaterina M Nestorovich
- Department of Biology, The Catholic University of America, 620 Michigan Avenue, Washington D.C., 20064, United States
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24
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Angevine CE, Robertson JWF, Dass A, Reiner JE. Laser-based temperature control to study the roles of entropy and enthalpy in polymer-nanopore interactions. SCIENCE ADVANCES 2021; 7:7/17/eabf5462. [PMID: 33883140 PMCID: PMC8059931 DOI: 10.1126/sciadv.abf5462] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/04/2021] [Indexed: 05/05/2023]
Abstract
Single-molecule approaches for probing the free energy of confinement for polymers in a nanopore environment are critical for the development of nanopore biosensors. We developed a laser-based nanopore heating approach to monitor the free energy profiles of such a single-molecule sensor. Using this approach, we measure the free energy profiles of two distinct polymers, polyethylene glycol and water-soluble peptides, as they interact with the nanopore sensor. Polyethylene glycol demonstrates a retention mechanism dominated by entropy with little sign of interaction with the pore, while peptides show an enthalpic mechanism, which can be attributed to physisorption to the nanopore (e.g., hydrogen bonding). To manipulate the energetics, we introduced thiolate-capped gold clusters [Au25(SG)18] into the pore, which increases the charge and leads to additional electrostatic interactions that help dissect the contribution that enthalpy and entropy make in this modified environment. These observations provide a benchmark for optimization of single-molecule nanopore sensors.
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Affiliation(s)
| | - Joseph W F Robertson
- Biophysics Group, Microsystems and Nanotechnology Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
| | - Amala Dass
- Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA
| | - Joseph E Reiner
- Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
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25
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Prajapati JD, Kleinekathöfer U, Winterhalter M. How to Enter a Bacterium: Bacterial Porins and the Permeation of Antibiotics. Chem Rev 2021; 121:5158-5192. [PMID: 33724823 DOI: 10.1021/acs.chemrev.0c01213] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Despite tremendous successes in the field of antibiotic discovery seen in the previous century, infectious diseases have remained a leading cause of death. More specifically, pathogenic Gram-negative bacteria have become a global threat due to their extraordinary ability to acquire resistance against any clinically available antibiotic, thus urging for the discovery of novel antibacterial agents. One major challenge is to design new antibiotics molecules able to rapidly penetrate Gram-negative bacteria in order to achieve a lethal intracellular drug accumulation. Protein channels in the outer membrane are known to form an entry route for many antibiotics into bacterial cells. Up until today, there has been a lack of simple experimental techniques to measure the antibiotic uptake and the local concentration in subcellular compartments. Hence, rules for translocation directly into the various Gram-negative bacteria via the outer membrane or via channels have remained elusive, hindering the design of new or the improvement of existing antibiotics. In this review, we will discuss the recent progress, both experimentally as well as computationally, in understanding the structure-function relationship of outer-membrane channels of Gram-negative pathogens, mainly focusing on the transport of antibiotics.
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Affiliation(s)
| | | | - Mathias Winterhalter
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen 28759, Germany
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26
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Berezhkovskii AM, Bezrukov SM. Capturing single molecules by nanopores: measured times and thermodynamics. Phys Chem Chem Phys 2021; 23:1610-1615. [PMID: 33410847 PMCID: PMC8075107 DOI: 10.1039/d0cp04747c] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In numerous nanopore sensing applications transient interruptions in ion current through single nanopores induced by capturing solute molecules are a source of information on how solutes interact with the nanopores. We show that the distribution of time spent by a single captured solute molecule in a nanopore is bimodal with the majority of capture events being too fast to be experimentally resolved. As a result, the exact mean durations of the event and inter-event interval are orders of magnitude shorter than their measured values. Moreover, the exact and measured mean durations have qualitatively different dependences on the molecule diffusivity. This leads to a formal contradiction with the thermodynamics of molecule partitioning between the bulk and the nanopore. Here we resolve this controversy. We also demonstrate that, surprisingly, the probability of finding a molecule in the nanopore, obtained from the ratio of the measured mean durations of the capture event and interevent interval, is essentially identical to the exact equilibrium thermodynamic probability.
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Affiliation(s)
- Alexander M Berezhkovskii
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA and Mathematical and Statistical Computing Laboratory, Office of Intramural Research, Center for Information Technology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sergey M Bezrukov
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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27
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Crnković A, Srnko M, Anderluh G. Biological Nanopores: Engineering on Demand. Life (Basel) 2021; 11:life11010027. [PMID: 33466427 PMCID: PMC7824896 DOI: 10.3390/life11010027] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/24/2020] [Accepted: 12/31/2020] [Indexed: 12/17/2022] Open
Abstract
Nanopore-based sensing is a powerful technique for the detection of diverse organic and inorganic molecules, long-read sequencing of nucleic acids, and single-molecule analyses of enzymatic reactions. Selected from natural sources, protein-based nanopores enable rapid, label-free detection of analytes. Furthermore, these proteins are easy to produce, form pores with defined sizes, and can be easily manipulated with standard molecular biology techniques. The range of possible analytes can be extended by using externally added adapter molecules. Here, we provide an overview of current nanopore applications with a focus on engineering strategies and solutions.
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28
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Galenkamp NS, Van Meervelt V, Mutter NL, van der Heide NJ, Wloka C, Maglia G. Preparation of Cytolysin A (ClyA) Nanopores. Methods Mol Biol 2021; 2186:11-18. [PMID: 32918726 DOI: 10.1007/978-1-0716-0806-7_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The ionic currents passing through nanopores can be used to sequence DNA and identify molecules at the single-molecule level. Recently, researchers have started using nanopores for the detection and analysis of proteins, providing a new platform for single-molecule enzymology studies and more efficient biomolecular sensing applications. For this approach, the homo-oligomeric Cytolysin A (ClyA) nanopore has been demonstrated as a powerful tool. Here, we describe a simple protocol allowing the production of ClyA nanopores. Monomers of ClyA are expressed in Escherichia coli and oligomerized in the presence of detergent. Subsequently, different oligomer variants are electrophoretically resolved and stored in a gel matrix for long-term use.
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Affiliation(s)
- Nicole Stéphanie Galenkamp
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Veerle Van Meervelt
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Natalie Lisa Mutter
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Nieck Jordy van der Heide
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Carsten Wloka
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands
| | - Giovanni Maglia
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands.
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29
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Haji Abdolvahab R, Niknam Hamidabad M. Pore shapes effects on polymer translocation. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2020; 43:76. [PMID: 33306147 DOI: 10.1140/epje/i2020-12001-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/12/2020] [Indexed: 06/12/2023]
Abstract
We translocated polymers through pores of different shapes and interaction patterns in three dimensions by Langevin molecular dynamics. There were four simple cylindrical pores of the same length but with different diameters. The results showed that even though decreasing the pore diameter would always decrease the translocation velocity, it was strongly dependent on the shape of the increased pore diameter. Although increasing the pore diameter made the translocation faster in simple cylindrical pores, it was complicated in different pore shapes, e.g. increasing the diameter in the middle decreased the translocation velocity. Investigating polymer shapes through the translocation process and comparing the shapes by the cumulative waiting time for different pore structures reveals the non-equilibrium properties of translocation. Moreover, polymer shape parameters such as gyration radius, polymer center of mass, and average aspect ratio help us to distinguish different pore shapes and/or different polymers.
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30
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Chinappi M, Yamaji M, Kawano R, Cecconi F. Analytical Model for Particle Capture in Nanopores Elucidates Competition among Electrophoresis, Electroosmosis, and Dielectrophoresis. ACS NANO 2020; 14:15816-15828. [PMID: 33170650 PMCID: PMC8016366 DOI: 10.1021/acsnano.0c06981] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 11/02/2020] [Indexed: 05/15/2023]
Abstract
The interaction between nanoparticles dispersed in a fluid and nanopores is governed by the interplay of hydrodynamical, electrical, and chemical effects. We developed a theory for particle capture in nanopores and derived analytical expressions for the capture rate under the concurrent action of electrical forces, fluid advection, and Brownian motion. Our approach naturally splits the average capture time in two terms, an approaching time due to the migration of particles from the bulk to the pore mouth and an entrance time associated with a free-energy barrier at the pore entrance. Within this theoretical framework, we described the standard experimental condition where a particle concentration is driven into the pore by an applied voltage, with specific focus on different capture mechanisms: under pure electrophoretic force, in the presence of a competition between electrophoresis and electroosmosis, and finally under dielectrophoretic reorientation of dipolar particles. Our theory predicts that dielectrophoresis is able to induce capture for both positive and negative voltages. We performed a dedicated experiment involving a biological nanopore (α-hemolysin) and a rigid dipolar dumbbell (realized with a β-hairpin peptide) that confirms the theoretically proposed capture mechanism.
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Affiliation(s)
- Mauro Chinappi
- Dipartimento
di Ingegneria Industriale, Università
di Roma Tor Vergata, Via del Politecnico 1, 00133 Rome, Italy
| | - Misa Yamaji
- Department
of Biotechnology and Life Science, Tokyo
University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Ryuji Kawano
- Department
of Biotechnology and Life Science, Tokyo
University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Fabio Cecconi
- CNR-Istituto
dei Sistemi Complessi, Via dei Taurini 19, I-00185 Rome, Italy
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Choudhary A, Joshi H, Chou HY, Sarthak K, Wilson J, Maffeo C, Aksimentiev A. High-Fidelity Capture, Threading, and Infinite-Depth Sequencing of Single DNA Molecules with a Double-Nanopore System. ACS NANO 2020; 14:15566-15576. [PMID: 33174731 PMCID: PMC8848087 DOI: 10.1021/acsnano.0c06191] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Nanopore sequencing of nucleic acids has an illustrious history of innovations that eventually made commercial nanopore sequencing possible. Nevertheless, the present nanopore sequencing technology leaves much room for improvement, especially with respect to accuracy of raw reads and detection of nucleotide modifications. Double-nanopore sequencing-an approach where a DNA molecule is pulled back and forth by a tug-of-war of two nanopores-could potentially improve single-molecule read accuracy and modification detection by offering multiple reads of the same DNA fragment. One principle difficulty in realizing such a technology is threading single-stranded DNA through both nanopores. Here, we describe and demonstrate through simulations a nanofluidic system for loading and threading DNA strands through a double-nanopore setup with nearly 100% fidelity. The high-efficiency loading is realized by using hourglass-shaped side channels that not only deliver the molecules to the nanopore but also retain molecules that missed the nanopore at the first passage to attempt the nanopore capture again. The second nanopore capture is facilitated by an orthogonal microfluidic flow that unravels the molecule captured by the first nanopore and delivers it to the capture volume of the second nanopore. We demonstrate the potential utility of our double-nanopore system for DNA sequencing by simulating repeat back-and-forth motion-flossing-of a DNA strand through the double-nanopore system. We show that repeat exposure of the same DNA fragments to the nanopore sensing volume considerably increases accuracy of the nucleotide sequence determination and that correlated displacement of ssDNA through the two nanopores may facilitate recognition of homopolymer fragments.
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Affiliation(s)
- Adnan Choudhary
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Himanshu Joshi
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Han-Yi Chou
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Kumar Sarthak
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - James Wilson
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Christopher Maffeo
- Department of Physics, 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
| | - Aleksei Aksimentiev
- Department of Physics, 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
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32
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Hu G, Fu J, Qiao Y, Meng H, Wang Z, Tu J, Lu Z. Molecular dynamics discrimination of the conformational states of calmodulin through solid-state nanopores. Phys Chem Chem Phys 2020; 22:19188-19194. [PMID: 32812567 DOI: 10.1039/d0cp02500c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
As a type of biological macromolecule, the conformation of proteins dynamically changes in a solution, which often results in a change in their function. However, traditional biological assays have significant drawbacks in detecting the conformation properties of proteins. Alternatively, nanopores have potential advantages in this area, which can detect protein in high throughput and without labelling. Herein, we investigated the translocation of calmodulins through silicon nitride nanopores using molecular dynamics (MD) simulation. Initially, the calmodulins were fixed in the nanopore. Distinguished blocked ionic currents were obtained between the two forms of calmodulin. Next, in the translocation simulations, a prominent difference in time resolution was easily found between the two states of calmodulin by using the appropriate voltage and comparable size of pore to protein, rp/rg→ 1, 4.5 nm (where rp is the protein radius and rg is the gyration radius). These simulations on the nanoscale are helpful for developing Ca2+-sensitive ion channels and nanodevices.
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Affiliation(s)
- Gang Hu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China.
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33
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Nanopore Enzymology to Study Protein Kinases and Their Inhibition by Small Molecules. Methods Mol Biol 2020. [PMID: 32918732 DOI: 10.1007/978-1-0716-0806-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Nanopore enzymology is a powerful single-molecule technique for the label-free study of enzymes using engineered protein nanopore sensors. The technique has been applied to protein kinases, where it has enabled the full repertoire of kinase function to be observed, including: kinetics of substrate binding and dissociation, product binding and dissociation, nucleotide binding, and reversible phosphorylation. Further, minor modifications enable the screening of type I kinase inhibitors and the determination of inhibition constants in a facile and label-free manner. Here, we describe the design and production of suitably engineered protein nanopores and their use for the determination of key mechanistic parameters of kinases. We also provide procedures for the determination of inhibition constants of protein kinase inhibitors.
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34
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Hsiao PY. Translocation of a Polyelectrolyte through a Nanopore in the Presence of Trivalent Counterions: A Comparison with the Cases in Monovalent and Divalent Salt Solutions. ACS OMEGA 2020; 5:19805-19819. [PMID: 32803076 PMCID: PMC7424739 DOI: 10.1021/acsomega.0c02647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/10/2020] [Indexed: 05/08/2023]
Abstract
A polyelectrolyte threading through a nanopore in a trivalent salt solution is investigated by means of molecular dynamics simulations under a reflective wall boundary. By varying the chain length N and the strength E of the driving electric field applied inside the pore, the translocation time is carefully calculated to get rid of the bouncing effect because of the boundary. The results are analyzed under the scaling form ⟨τ⟩ ∼ N α E -δ and four driving force regimes; namely, the unbiased, the weakly driven, the strongly driven trumpet, and the strongly driven isoflux regime, are distinguished. The exponents are calculated in each regime and compared with the cases in the monovalent and divalent salt solutions. Owing to strong condensation of counter ions, the changes of the exponents in the force regimes are found to be nontrivial. A large increase in translocation time can be, however, achieved as the driving field is weak. The variations of the chain size, the ion condensation, and the effective chain charge show that the process is proceeded in a quasi-equilibrium way in the unbiased regime and deviated to exhibit strong nonequilibrium characteristics as E increases. Several astonishing scaling behaviors of the waiting time function, the translocation velocity, and the diffusion properties are discovered in the study. The results provide deep insights into the phenomena of polyelectrolyte translocation in various salt solutions at different driving forces.
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Affiliation(s)
- Pai-Yi Hsiao
- Department
of Engineering and System Science, National
Tsing Hua University, Hsinchu, Taiwan 30013, R. O. C
- Institute
of Nuclear Engineering and Science, National
Tsing Hua University, Hsinchu, Taiwan 30013, R. O. C
- ,
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35
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Nagarajan K, Chen SB. Polyelectrolyte Translocation through a Corrugated Nanopore. MACROMOL THEOR SIMUL 2020. [DOI: 10.1002/mats.202000042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Karthik Nagarajan
- Department of Chemical & Biomolecular EngineeringNational University of Singapore Singapore 117585 Singapore
| | - Shing Bor Chen
- Department of Chemical & Biomolecular EngineeringNational University of Singapore Singapore 117585 Singapore
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36
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Sarabadani J, Buyukdagli S, Ala-Nissila T. Pulling a DNA molecule through a nanopore embedded in an anionic membrane: tension propagation coupled to electrostatics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:385101. [PMID: 32408289 DOI: 10.1088/1361-648x/ab9342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
We consider the influence of electrostatic forces on driven translocation dynamics of a flexible polyelectrolyte being pulled through a nanopore by an external force on the head monomer. To this end, we augment the iso-flux tension propagation theory with electrostatics for a negatively charged biopolymer pulled through a nanopore embedded in a similarly charged anionic membrane. We show that in the realistic case of a single-stranded DNA molecule, dilute salt conditions characterized by weak charge screening, and a negatively charged membrane, the translocation dynamics is unexpectedly accelerated despite the presence of large repulsive electrostatic interactions between the polymer coil on thecisside and the charged membrane. This is due to the rapid release of the electrostatic potential energy of the coil during translocation, leading to an effectively attractive force that assists end-driven translocation. The speedup results in non-monotonic polymer length and membrane charge dependence of the exponentαcharacterizing the translocation timeτ∝N0αof the polymer with lengthN0. In the regime of long polymersN0 ≳ 500, the translocation exponent exceeds its upper limitα= 2 previously observed for the same system without electrostatic interactions.
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Affiliation(s)
- Jalal Sarabadani
- School of Nano Science, Institute for Research in Fundamental Sciences (IPM), 19395-5531, Tehran, Iran
| | | | - Tapio Ala-Nissila
- Department of Applied Physics and QTF Center of Excellence, Aalto University, P.O. Box 11000, FI-00076 Aalto, Espoo, Finland
- Interdisciplinary Centre for Mathematical Modelling and Department of Mathematical Sciences, Loughborough University, Loughborough, Leicestershire LE11 3TU, United Kingdom
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37
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Affiliation(s)
- Karthik Nagarajan
- K. Nagarajan, Prof. S. B. ChenDepartment of Chemical & Biomolecular EngineeringNational University of Singapore Singapore 117585 Singapore
| | - Shing Bor Chen
- K. Nagarajan, Prof. S. B. ChenDepartment of Chemical & Biomolecular EngineeringNational University of Singapore Singapore 117585 Singapore
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38
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McClintic WT, Taylor GJ, Simpson ML, Collier CP. Macromolecular Crowding Affects Voltage-Dependent Alamethicin Pore Formation in Lipid Bilayer Membranes. J Phys Chem B 2020; 124:5095-5102. [DOI: 10.1021/acs.jpcb.0c01650] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- William T. McClintic
- The Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Graham J. Taylor
- The Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Michael L. Simpson
- The Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Nanophase Material Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - C. Patrick Collier
- The Bredesen Center for Interdisciplinary Research, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Nanophase Material Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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39
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Abstract
The molecular scale pore structure, called nanopore, can be formed from protein ion channels by genetic engineering or fabricated on solid substrates using fashion nanotechnology. Target molecules in interaction with the functionalized lumen of nanopore, can produce characteristic changes in the pore conductance, which act as fingerprints, allowing us to identify single molecules and simultaneously quantify each target species in the mixture. Nanopore sensors have been created for tremendous biomedical detections, with targets ranging from metal ions, drug compounds and cellular second messengers, to proteins and DNAs. Recently, we have used the nanopore technique to dissect folding and unfolding mechanism of a single G-quadruplex DNA aptamer regulated by a variety of ions; we also created a portable and durable molecular device that integrated a protein pore sensor with a solidified lipid membrane for real-time detection.
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Affiliation(s)
- L Q Gu
- Biological Engineering and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211, USA
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40
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DNA Nanotechnology for Building Sensors, Nanopores and Ion-Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1174:331-370. [PMID: 31713205 DOI: 10.1007/978-981-13-9791-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
DNA nanotechnology has revolutionised the capabilities to shape and control three-dimensional structures at the nanometre scale. Designer sensors, nanopores and ion-channels built from DNA have great potential for both cross-disciplinary research and applications. Here, we introduce the concept of structural DNA nanotechnology, including DNA origami, and give an overview of the work flow from design to assembly, characterisation and application of DNA-based functional systems. Chemical functionalisation of DNA has opened up pathways to transform static DNA structures into dynamic nanomechanical sensors. We further introduce nanopore sensing as a powerful label-free single-molecule technique and discuss how it can benefit from DNA nanotechnology. Especially exciting is the possibility to create membrane-inserted DNA nanochannels that mimic their protein-based natural counterparts in form and function. In this chapter we review the status quo of DNA sensors, nanopores and ion channels, highlighting opportunities and challenges for their future development.
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41
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Lenart WR, Kong W, Oltjen WC, Hore MJA. Translocation of soft phytoglycogen nanoparticles through solid-state nanochannels. J Mater Chem B 2019; 7:6428-6437. [PMID: 31465081 DOI: 10.1039/c9tb01048c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phytoglycogen nanoparticles are soft, naturally-derived nanomaterials with a highly uniform size near 35 nm. Their interior is composed of a highly-branched polysaccharide core that contains more than 200% of its dry mass in water. In this work, we measure the translocation of phytoglycogen particles by observing blockade events they create when occluding solid-state nanochannels with diameters between 60 and 100 nm. The translocation signals are interpreted using Poisson-Nernst-Planck calculations with a "hardness parameter" that describes the extent to which solvent can penetrate through the interior of the particles. Theory and experiment were found to be in quantitative agreement, allowing us to extract physical characteristics of the particles on a per particle basis.
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Affiliation(s)
- William R Lenart
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, USA.
| | - Weiwei Kong
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, USA.
| | - William C Oltjen
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, USA.
| | - Michael J A Hore
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, USA.
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42
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Abstract
Although nanopores have shown tremendous promise for use in DNA sequencing, the rate of translocation through most pores studied previously is too rapid for the genetic information to be read accurately. In this study, dissipative particle dynamics simulations were employed to investigate the feasibility of using tortuous nanopores to control the rate of polyelectrolyte translocation. Unlike many previous studies, our simulation method incorporates the effects of hydrodynamic and electrostatic interactions and the spatial variation of electric field strength. The average translocation time, ⟨τ⟩, increases with the pore length and tortuosity but decreases as the pore width increases. For the longest pore investigated, the introduction of tortuosity results in ⟨τ⟩ increasing by as much as 187% as compared to a straight pore. The temporal variation of bond tension indicates that slower translocation in tortuous nanopores is caused by inhibition of tension propagation.
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Affiliation(s)
- Karthik Nagarajan
- Department of Chemical and Biomolecular Engineering , National University of Singapore , 117585 , Singapore
| | - Shing Bor Chen
- Department of Chemical and Biomolecular Engineering , National University of Singapore , 117585 , Singapore
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43
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Wang N, Liu R, Asmare N, Chu CH, Sarioglu AF. Processing code-multiplexed Coulter signals via deep convolutional neural networks. LAB ON A CHIP 2019; 19:3292-3304. [PMID: 31482906 DOI: 10.1039/c9lc00597h] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Beyond their conventional use of counting and sizing particles, Coulter sensors can be used to spatially track suspended particles, with multiple sensors distributed over a microfluidic chip. Code-multiplexing of Coulter sensors allows such integration to be implemented with simple hardware but requires advanced signal processing to extract multi-dimensional information from the output waveform. In this work, we couple deep learning-based signal analysis with microfluidic code-multiplexed Coulter sensor networks. Specifically, we train convolutional neural networks to analyze Coulter waveforms not only to recognize certain sensor waveform patterns but also to resolve interferences among them. Our technology predicts the size, speed, and location of each detected particle. We show that the algorithm yields a >90% pattern recognition accuracy for distinguishing non-correlated waveform patterns at a processing speed that can potentially enable real-time microfluidic assays. Furthermore, once trained, the algorithm can readily be applied for processing electrical data from other microfluidic devices integrated with the same Coulter sensor network.
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Affiliation(s)
- Ningquan Wang
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Ruxiu Liu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Norh Asmare
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - Chia-Heng Chu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.
| | - A Fatih Sarioglu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA. and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA and Institute of Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, GA 30332, USA
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44
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Nagarajan K, Chen SB. Flow-Induced Translocation of Star Polymers through a Nanopore. J Phys Chem B 2019; 123:7919-7925. [PMID: 31461281 DOI: 10.1021/acs.jpcb.9b07066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The flow-induced translocation of star polymers through a cylindrical nanopore has been studied using dissipative particle dynamics (DPD) simulations. The number of arms, f, was varied with the total number of monomers, N, kept constant. The effect of simulating the capture of the polymer into the pore upon the mean translocation time, <τt>, has been investigated by varying the chain's initial location. The results indicate that the incorporation of the capture process results in a reduction of <τt> by up to 15%. This is because the chain's initial location affects the extent of its stretching along the flow direction during translocation. <τt> exhibits nonmonotonic variation with f, in agreement with recently reported results for electric field-driven translocation of star polymers. Its value is larger and shows greater variation with f when the solvent quality is better. For the same value of f, the capture occurs faster in a good solvent. In addition, <τt> is greater for a semiflexible chain than its flexible counterpart as the time required for the branch point to enter the nanopore is longer in the former case.
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Affiliation(s)
- Karthik Nagarajan
- Department of Chemical & Biomolecular Engineering , National University of Singapore , 117585 Singapore
| | - Shing Bor Chen
- Department of Chemical & Biomolecular Engineering , National University of Singapore , 117585 Singapore
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45
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Ying YL, Long YT. Nanopore-Based Single-Biomolecule Interfaces: From Information to Knowledge. J Am Chem Soc 2019; 141:15720-15729. [DOI: 10.1021/jacs.8b11970] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Yi-Lun Ying
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Yi-Tao Long
- State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China
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46
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Wang Y, Wang Y, Du X, Yan S, Zhang P, Chen HY, Huang S. Electrode-free nanopore sensing by DiffusiOptoPhysiology. SCIENCE ADVANCES 2019; 5:eaar3309. [PMID: 31523706 PMCID: PMC6731070 DOI: 10.1126/sciadv.aar3309] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 08/02/2019] [Indexed: 05/24/2023]
Abstract
A wide variety of single molecules can be identified by nanopore sensing. However, all reported nanopore sensing applications result from the same measurement configuration adapted from electrophysiology. Although urgently needed in commercial nanopore sequencing, parallel electrophysiology recording is limited in its cost and its throughput due to the introduced complexities from electronic integration. We present the first electrode-free nanopore sensing method defined as DiffusiOptoPhysiology (DOP), in which single-molecule events are monitored optically without any electrical connections. Single-molecule sensing of small molecules, macromolecules, and biomacromolecules was subsequently demonstrated. As a further extension, a fingertip-sized, multiplexed chip with single-molecule sensing capabilities has been introduced, which suggests a new concept of clinical diagnosis using disposable nanopore sensors. DOP, which is universally compatible with all types of channels and a variety of fluorescence imaging platforms, may benefit diverse areas such as nanopore sequencing, drug screening, and channel protein investigations.
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Affiliation(s)
- Yuqin Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Yu Wang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Xiaoyu Du
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Shuanghong Yan
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
| | - Hong-Yuan Chen
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
- School of Chemistry and Chemical Engineering, Nanjing University, 210023 Nanjing, China
- Collaborative Innovation Center of Chemistry for Life Sciences, Nanjing University, 210023 Nanjing, China
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47
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de Vreede LJ, Ying C, Houghtaling J, Figueiredo Da Silva J, Hall AR, Lovera A, Mayer M. Wafer-scale fabrication of fused silica chips for low-noise recording of resistive pulses through nanopores. NANOTECHNOLOGY 2019; 30:265301. [PMID: 30849769 DOI: 10.1088/1361-6528/ab0e2a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This paper presents a maskless method to manufacture fused silica chips for low-noise resistive-pulse sensing. The fabrication includes wafer-scale density modification of fused silica with a femtosecond-pulsed laser, low-pressure chemical vapor deposition (LPVCD) of silicon nitride (SiN x ) and accelerated chemical wet etching of the laser-exposed regions. This procedure leads to a freestanding SiN x window, which is permanently attached to a fused silica support chip and the resulting chips are robust towards Piranha cleaning at ∼80 °C. After parallel chip manufacturing, we created a single nanopore in each chip by focused helium-ion beam or by controlled breakdown. Compared to silicon chips, the resulting fused silica nanopore chips resulted in a four-fold improvement of both the signal-to-noise ratio and the capture rate for signals from the translocation of IgG1 proteins at a recording bandwidth of 50 kHz. At a bandwidth of ∼1 MHz, the noise from the fused silica nanopore chips was three- to six-fold reduced compared to silicon chips. In contrast to silicon chips, fused silica chips showed no laser-induced current noise-a significant benefit for experiments that strive to combine nanopore-based electrical and optical measurements.
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Affiliation(s)
- Lennart J de Vreede
- Biophysics group, Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland
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48
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Westerlund E, Valfridsson C, Yi DX, Persson JJ. The Secreted Virulence Factor NADase of Group A Streptococcus Inhibits P2X7 Receptor-Mediated Release of IL-1β. Front Immunol 2019; 10:1385. [PMID: 31275321 PMCID: PMC6591467 DOI: 10.3389/fimmu.2019.01385] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/03/2019] [Indexed: 12/29/2022] Open
Abstract
The common human pathogen Group A Streptococcus (GAS) causes superficial as well as invasive, life-threatening diseases. An increase in the occurrence of invasive GAS infection by strains of the M1 and M89 serotypes has been correlated with increased expression of the genetically and functionally linked virulence factors streptolysin O (SLO) and β-NAD+-glycohydrolase (NADase). NADase affects host cells differently depending on its location: its SLO-dependent translocation into the cytosol can lead to cell death through β-NAD+ depletion, while extracellularly located NADase inhibits IL-1β release downstream of Nlrp3 inflammasome activation. In this study, we use a macrophage infection model to investigate the NADase-dependent inhibition of IL-1β release. We show that bacteria expressing a functional NADase evade P2X7 activation, while infection with a NADase-deficient GAS strain leads to a P2X7-mediated increase in IL-1β. Further, our data indicate that in the absence of NADase, IL-1β is released through both P2X7-dependent and -independent pathways, although the precise mechanisms of how this occur are still unclear. This study adds information about the mechanism by which NADase regulates inflammasome-dependent IL-1β release, which may in part explain why increased NADase expression correlates with bacterial virulence.
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Affiliation(s)
- Elsa Westerlund
- Immunology Section, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Christine Valfridsson
- Immunology Section, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Daisy X Yi
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Jenny J Persson
- Immunology Section, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
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Stachiewicz A, Molski A. Sequence-Dependent Unzipping Dynamics of DNA Hairpins in a Nanopore. J Phys Chem B 2019; 123:3199-3209. [PMID: 30920837 DOI: 10.1021/acs.jpcb.9b00183] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
By applying an electric field to an insulating membrane, movement of charged particles through a nanopore can be induced. The measured ionic current reports on biomolecules passing through the nanopore. In this paper, we explore the sequence-dependent dynamics of DNA unzipping using our recently developed coarse-grained model. We estimated three molecular profiles (the potential of mean force, position-dependent diffusion coefficient, and position-dependent effective charge) for the DNA unzipping of four hairpins with different sequences. We found that the molecular profiles are correlated with the ionic current and molecular events. We also explored the unzipping kinetics using Brownian dynamics. We found that the effect of hairpin structure on the unzipping/translocation times is not only energetic (weaker hairpins unzip more quickly) but also kinetic (different unzipping and translocation pathways play an important role).
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Affiliation(s)
- Anna Stachiewicz
- Department of Chemistry , Adam Mickiewicz University , Poznan 61-614 , Poland
| | - Andrzej Molski
- Department of Chemistry , Adam Mickiewicz University , Poznan 61-614 , Poland
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Abstract
The electric field driven translocation of charged star polymers through a cylindrical nanopore has been studied using dissipative particle dynamics simulations. The critical field strength required to induce translocation depends on both the number of arms and the number of beads per arm. It may therefore be possible to separate star polyelectrolytes of different arm lengths using electric field driven translocation through a nanopore. The average translocation time exhibits nonmonotonic variation with the number of arms for good solvent conditions. During translocation, a star polymer with many arms is stretched along the pore axis to a lesser extent as compared to its linear counterpart. Unlike a linear chain that shows tension propagation with large tensions for bonds about to enter the pore, a star has the tensest bonds closest to the branch point whose connectivity to multiple arms raises difficulty for its entry and passage.
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Affiliation(s)
- Karthik Nagarajan
- Department of Chemical & Biomolecular Engineering , National University of Singapore , 117585 , Singapore
| | - Shing Bor Chen
- Department of Chemical & Biomolecular Engineering , National University of Singapore , 117585 , Singapore
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