1
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Shorkey SA, Zhang Y, Sharp J, Clingman S, Nguyen L, Chen J, Chen M. Tuning single-molecule ClyA nanopore tweezers for real-time tracking of the conformational dynamics of West Nile viral NS2B/NS3 protease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.14.594247. [PMID: 38798384 PMCID: PMC11118314 DOI: 10.1101/2024.05.14.594247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The flaviviral NS2B/NS3 protease is a conserved enzyme required for flavivirus replication. Its highly dynamic conformation poses major challenges but also offers opportunities for antiviral inhibition. Here, we established a nanopore tweezers-based platform to monitor NS2B/NS3 conformational dynamics in real-time. Molecular simulations coupled with electrophysiology revealed that the protease could be captured in the middle of the ClyA nanopore lumen, stabilized mainly by dynamic electrostatic interactions. We designed a new Salmonella typhi ClyA nanopore with enhanced nanopore/protease interaction that can resolve the open and closed states at the single-molecule level for the first time. We demonstrated that the tailored ClyA could track the conformational transitions of the West Nile NS2B/NS3 protease and unravel the conformational energy landscape of various protease constructs through population and kinetic analysis. The new ClyA-protease platform paves a way to high-throughput screening strategies for discovering new allosteric inhibitors that target the NS2B and NS3 interface.
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2
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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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3
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Mittal S, Manna S, Pathak B. Machine Learning Prediction of the Transmission Function for Protein Sequencing with Graphene Nanoslit. ACS APPLIED MATERIALS & INTERFACES 2022; 14:51645-51655. [PMID: 36374991 DOI: 10.1021/acsami.2c13405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Protein sequencing has rapidly changed the landscape of healthcare and life science by accelerating the growth of diagnostics and personalized medicines for a variety of fatal diseases. Next-generation nanopore/nanoslit sequencing is promising to achieve single-molecule resolution with chromosome-size-long readability. However, due to inherent complexity, high-throughput sequencing of all 20 amino acids demands different approaches. Aiming to accelerate the detection of amino acids, a general machine learning (ML) method has been developed for quick and accurate prediction of the transmission function for amino acid sequencing. Among the utilized ML models, the XGBoost regression model is found to be the most effective algorithm for fast prediction of the transmission function with a very low test root-mean-square error (RMSE ∼0.05). In addition, using the random forest ML classification technique, we are able to classify the neutral amino acids with a prediction accuracy of 100%. Therefore, our approach is an initiative for the prediction of the transmission function through ML and can provide a platform for the quick identification of amino acids with high accuracy.
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Affiliation(s)
- Sneha Mittal
- Department of Chemistry, Indian Institute of Technology (IIT) Indore, Indore, Madhya Pradesh453552, India
| | - Souvik Manna
- Department of Chemistry, Indian Institute of Technology (IIT) Indore, Indore, Madhya Pradesh453552, India
| | - Biswarup Pathak
- Department of Chemistry, Indian Institute of Technology (IIT) Indore, Indore, Madhya Pradesh453552, India
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4
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Zollo G, Civitarese T. Ab Initio Properties of Hybrid Cove-Edged Graphene Nanoribbons as Metallic Electrodes for Peptide Sequencing via Transverse Tunneling Current. ACS OMEGA 2022; 7:25164-25170. [PMID: 35910163 PMCID: PMC9330076 DOI: 10.1021/acsomega.2c01917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Recently synthesized metallic cove-edged graphene nanoribbons are considered for use as one-dimensional (1D) electrodes for ideal atomistically resolved recognition of amino acids. To this purpose a narrow nanogap device is considered, and the transversal tunneling current flowing across it is calculated during the translocation of a model Gly homopeptide using the nonequilibrium Green function scheme, based on density functional theory. We show that the signal collected from the metallic spin states is characterized by a double peak per residue in analogy with the results obtained with 1D graphene nanoribbon template electrodes. The presented results pave the way for experimentally feasible atomistically resolved tunneling current recognition using metallic edge engineered graphene electrodes obtained by bottom-up fabrication strategies.
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Affiliation(s)
- Giuseppe Zollo
- Dipartimento di Scienze di Base e Applicate
per l’Ingegneria, University of Rome
“La Sapienza”, Via Antonio Scarpa 14-16, 00161 Rome, Italy
| | - Tommaso Civitarese
- Dipartimento di Scienze di Base e Applicate
per l’Ingegneria, University of Rome
“La Sapienza”, Via Antonio Scarpa 14-16, 00161 Rome, Italy
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5
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Dessaux D, Mathé J, Ramirez R, Basdevant N. Current Rectification and Ionic Selectivity of α-Hemolysin: Coarse-Grained Molecular Dynamics Simulations. J Phys Chem B 2022; 126:4189-4199. [PMID: 35657610 DOI: 10.1021/acs.jpcb.2c01028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In order to understand the physical processes of nanopore experiments at the molecular level, microscopic information from molecular dynamics is greatly needed. Coarse-grained models are a good alternative to classical all-atom models since they allow longer and faster simulations. We performed coarse-grained molecular dynamics of the ionic transport through the α-hemolysin protein nanopore, inserted into a lipid bilayer surrounded by solvent and ions. For this purpose, we used the MARTINI coarse-grained force field and its polarizable water solvent (PW). Moreover, the electric potential difference applied experimentally was mimicked by the application of an electric field to the system. We present, in this study, the results of 1.5 μs long-molecular dynamics simulations of 12 different systems for which different charged amino acids were neutralized, each of them in the presence of nine different electric fields ranging between ±0.04 V/nm (a total of around 100 simulations). We were able to observe several specific features of this pore, current asymmetry and anion selectivity, in agreement with previous studies and experiments, and we identified the charged amino acids responsible for these current behaviors, therefore validating our coarse-grain approach to study ionic transport through nanopores. We also propose a microscopic explanation of these ionic current features using ionic density maps.
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Affiliation(s)
- Delphine Dessaux
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
| | - Jérôme Mathé
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
| | - Rosa Ramirez
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
| | - Nathalie Basdevant
- Université Paris-Saclay, Univ Evry, CNRS, LAMBE UMR8587, Évry-Courcouronnes 91025, France
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6
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Rattu P, Glencross F, Mader SL, Skylaris CK, Matthews SJ, Rouse SL, Khalid S. Atomistic level characterisation of ssDNA translocation through the E. coli proteins CsgG and CsgF for nanopore sequencing. Comput Struct Biotechnol J 2021; 19:6417-6430. [PMID: 34938416 PMCID: PMC8649110 DOI: 10.1016/j.csbj.2021.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/12/2021] [Accepted: 11/12/2021] [Indexed: 12/01/2022] Open
Abstract
Two proteins of the Escherichia coli membrane protein complex, CsgG and CsgF, are studied as proteinaceous nanopores for DNA sequencing. It is highly desirable to control the DNA as it moves through the pores, this requires characterisation of DNA translocation and subsequent optimization of the pores. In order to inform protein engineering to improve the pores, we have conducted a series of molecular dynamics simulations to characterise the mechanical strength and conformational dynamics of CsgG and the CsgG-CsgF complex and how these impact ssDNA, water and ion movement. We find that the barrel of CsgG is more susceptible to damage from external electric fields compared to the protein vestibule. Furthermore, the presence of CsgF within the CsgG-CsgF complex enables the complex to withstand higher electric fields. We find that the eyelet loops of CsgG play a key role in both slowing the translocation rate of DNA and modulating the conductance of the pore. CsgF also impacts the DNA translocation rate, but to a lesser degree than CsgG.
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Affiliation(s)
- Punam Rattu
- School of Chemistry, University of Southampton, SO17 1BJ, United Kingdom
| | - Flo Glencross
- Department of Life Sciences, Imperial College London, SW7 2AZ, United Kingdom
| | - Sophie L Mader
- Department of Biochemistry, University of Oxford, OX1 3QU, United Kingdom
| | | | - Stephen J Matthews
- Department of Life Sciences, Imperial College London, SW7 2AZ, United Kingdom
| | - Sarah L Rouse
- Department of Life Sciences, Imperial College London, SW7 2AZ, United Kingdom
| | - Syma Khalid
- School of Chemistry, University of Southampton, SO17 1BJ, United Kingdom
- Department of Biochemistry, University of Oxford, OX1 3QU, United Kingdom
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7
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Jiang W, Lin YC, Botello-Smith W, Contreras JE, Harris AL, Maragliano L, Luo YL. Free energy and kinetics of cAMP permeation through connexin26 via applied voltage and milestoning. Biophys J 2021; 120:2969-2983. [PMID: 34214529 DOI: 10.1016/j.bpj.2021.06.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/08/2021] [Accepted: 06/17/2021] [Indexed: 11/18/2022] Open
Abstract
The connexin family is a diverse group of highly regulated wide-pore channels permeable to biological signaling molecules. Despite the critical roles of connexins in mediating selective molecular signaling in health and disease, the basis of molecular permeation through these pores remains unclear. Here, we report the thermodynamics and kinetics of binding and transport of a second messenger, adenosine-3',5'-cyclophosphate (cAMP), through a connexin26 hemichannel (Cx26). First, inward and outward fluxes of cAMP molecules solvated in KCl solution were obtained from 4 μs of ± 200 mV simulations. These fluxes data yielded a single-channel permeability of cAMP and cAMP/K+ permeability ratio consistent with experimentally measured values. The results from voltage simulations were then compared with the potential of mean force (PMF) and the mean first passage times (MFPTs) of a single cAMP without voltage, obtained from a total of 16.5 μs of Voronoi-tessellated Markovian milestoning simulations. Both the voltage simulations and the milestoning simulations revealed two cAMP-binding sites, for which the binding constants KD and dissociation rates koff were computed from PMF and MFPTs. The protein dipole inside the pore produces an asymmetric PMF, reflected in unequal cAMP MFPTs in each direction once within the pore. The free energy profiles under opposite voltages were derived from the milestoning PMF and revealed the interplay between voltage and channel polarity on the total free energy. In addition, we show how these factors influence the cAMP dipole vector during permeation, and how cAMP affects the local and nonlocal pore diameter in a position-dependent manner.
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Affiliation(s)
- Wenjuan Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California
| | - Yi-Chun Lin
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California
| | - Wesley Botello-Smith
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California
| | - Jorge E Contreras
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California.
| | - Andrew L Harris
- Department of Pharmacology, Physiology, and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey.
| | - Luca Maragliano
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy; Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy.
| | - Yun Lyna Luo
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California.
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8
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Mitscha-Baude G, Stadlbauer B, Howorka S, Heitzinger C. Protein Transport through Nanopores Illuminated by Long-Time-Scale Simulations. ACS NANO 2021; 15:9900-9912. [PMID: 34096722 PMCID: PMC8291773 DOI: 10.1021/acsnano.1c01078] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 05/28/2021] [Indexed: 06/12/2023]
Abstract
The transport of molecules through nanoscale confined space is relevant in biology, biosensing, and industrial filtration. Microscopically modeling transport through nanopores is required for a fundamental understanding and guiding engineering, but the short duration and low replica number of existing simulation approaches limit statistically relevant insight. Here we explore protein transport in nanopores with a high-throughput computational method that realistically simulates hundreds of up to seconds-long protein trajectories by combining Brownian dynamics and continuum simulation and integrating both driving forces of electroosmosis and electrophoresis. Ionic current traces are computed to enable experimental comparison. By examining three biological and synthetic nanopores, our study answers questions about the kinetics and mechanism of protein transport and additionally reveals insight that is inaccessible from experiments yet relevant for pore design. The discovery of extremely frequent unhindered passage can guide the improvement of biosensor pores to enhance desired biomolecular recognition by pore-tethered receptors. Similarly, experimentally invisible nontarget adsorption to pore walls highlights how to improve recently developed DNA nanopores. Our work can be expanded to pressure-driven flow to model industrial nanofiltration processes.
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Affiliation(s)
| | - Benjamin Stadlbauer
- Institute
of Analysis and Scientific Computing, TU
Wien, Vienna, 1040, Austria
| | - Stefan Howorka
- Department
of Chemistry, Institute of Structural Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
- Institute
of Biophysics, Johannes Kepler University
Linz, Linz, 4020, Austria
| | - Clemens Heitzinger
- Institute
of Analysis and Scientific Computing, TU
Wien, Vienna, 1040, Austria
- School
of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona 85287, United States
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9
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Desikan R, Behera A, Maiti PK, Ayappa KG. Using multiscale molecular dynamics simulations to obtain insights into pore forming toxin mechanisms. Methods Enzymol 2021; 649:461-502. [PMID: 33712196 DOI: 10.1016/bs.mie.2021.01.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Pore forming toxins (PFTs) are virulent proteins released by several species, including many strains of bacteria, to attack and kill host cells. In this article, we focus on the utility of molecular dynamics (MD) simulations and the molecular insights gleaned from these techniques on the pore forming pathways of PFTs. In addition to all-atom simulations which are widely used, coarse-grained MARTINI models and structure-based models have also been used to study PFTs. Here, the emphasis is on methods and techniques involved while setting up, monitoring, and evaluating properties from MD simulations of PFTs in a membrane environment. We draw from several case studies to illustrate how MD simulations have provided molecular insights into protein-protein and protein-lipid interactions, lipid dynamics, conformational transitions and structures of both the oligomeric intermediates and assembled pore structures.
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Affiliation(s)
- Rajat Desikan
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
| | - Amit Behera
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India
| | - Prabal K Maiti
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bengaluru, India
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, Indian Institute of Science, Bengaluru, India; Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India.
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10
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Yin YD, Zhang L, Leng XZ, Gu ZY. Harnessing biological nanopore technology to track chemical changes. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.116091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Willems K, Ruić D, L R Lucas F, Barman U, Verellen N, Hofkens J, Maglia G, Van Dorpe P. Accurate modeling of a biological nanopore with an extended continuum framework. NANOSCALE 2020; 12:16775-16795. [PMID: 32780087 DOI: 10.1039/d0nr03114c] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Despite the broad success of biological nanopores as powerful instruments for the analysis of proteins and nucleic acids at the single-molecule level, a fast simulation methodology to accurately model their nanofluidic properties is currently unavailable. This limits the rational engineering of nanopore traits and makes the unambiguous interpretation of experimental results challenging. Here, we present a continuum approach that can faithfully reproduce the experimentally measured ionic conductance of the biological nanopore Cytolysin A (ClyA) over a wide range of ionic strengths and bias potentials. Our model consists of the extended Poisson-Nernst-Planck and Navier-Stokes (ePNP-NS) equations and a computationally efficient 2D-axisymmetric representation for the geometry and charge distribution of the nanopore. Importantly, the ePNP-NS equations achieve this accuracy by self-consistently considering the finite size of the ions and the influence of both the ionic strength and the nanoscopic scale of the pore on the local properties of the electrolyte. These comprise the mobility and diffusivity of the ions, and the density, viscosity and relative permittivity of the solvent. Crucially, by applying our methodology to ClyA, a biological nanopore used for single-molecule enzymology studies, we could directly quantify several nanofluidic characteristics difficult to determine experimentally. These include the ion selectivity, the ion concentration distributions, the electrostatic potential landscape, the magnitude of the electro-osmotic flow field, and the internal pressure distribution. Hence, this work provides a means to obtain fundamental new insights into the nanofluidic properties of biological nanopores and paves the way towards their rational engineering.
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Affiliation(s)
- Kherim Willems
- KU Leuven, Department of Chemistry, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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12
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Paul S, Ainavarapu SRK, Venkatramani R. Variance of Atomic Coordinates as a Dynamical Metric to Distinguish Proteins and Protein-Protein Interactions in Molecular Dynamics Simulations. J Phys Chem B 2020; 124:4247-4262. [PMID: 32281802 DOI: 10.1021/acs.jpcb.0c01191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Protein dynamics is a manifestation of the complex trajectories of these biomolecules on a multidimensional rugged potential energy surface (PES) driven by thermal energy. At present, computational methods such as atomistic molecular dynamics (MD) simulations can describe thermal protein conformational changes in fully solvated environments over millisecond timescales. Despite these advances, a quantitative assessment of protein dynamics remains a complicated topic, intricately linked to issues such as sampling convergence and the identification of appropriate reaction coordinates/structural features to describe protein conformational states and motions. Here, we present the cumulative variance of atomic coordinate fluctuations (CVCF) along trajectories as an intuitive PES sensitive metric to assess both the extent of sampling and protein dynamics captured in MD simulations. We first examine the sampling problem in model one- (1D) and two-dimensional (2D) PES to demonstrate that the CVCF when traced as a function of the sampling variable (time in MD simulations) can identify local and global equilibria. Further, even far from global equilibrium, a situation representative of standard MD trajectories of proteins, the CVCF can distinguish different PES and therefore resolve the resultant protein dynamics. We demonstrate the utility of our CVCF analysis by applying it to distinguish the dynamics of structurally homologous proteins from the ubiquitin family (ubiquitin, SUMO1, SUMO2) and ubiquitin protein-protein interactions. Our CVCF analysis reveals that differential side-chain dynamics from the structured part of the protein (the conserved β-grasp fold) present distinct protein PES to distinguish ubiquitin from SUMO isoforms. Upon binding to two functionally distinct protein partners (UBCH5A and UEV), intrinsic ubiquitin dynamics changes to reflect the binding context even though the two proteins have similar binding modes, which lead to negligible (sub-angstrom scale) structural changes.
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Affiliation(s)
- Sanjoy Paul
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, Maharashtra, India
| | - Sri Rama Koti Ainavarapu
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, Maharashtra, India
| | - Ravindra Venkatramani
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Dr. Homi Bhabha Road, Colaba, Mumbai 400005, Maharashtra, India
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13
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Cecconi F, Chinappi M. Native-state fingerprint on the ubiquitin translocation across a nanopore. Phys Rev E 2020; 101:032401. [PMID: 32290013 DOI: 10.1103/physreve.101.032401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 02/11/2020] [Indexed: 11/07/2022]
Abstract
We study the translocation of the ubiquitin molecule (Ubq) across a channel with a double section which constitutes a general feature of several transmembrane nanopores such as the α-hemolysin (αHL). Our purpose is to establish the structure-dependent character of the Ubq translocation pathway. This implies to find the correspondence, if any, between the translocational unfolding steps and the Ubq native state. For this reason, it is convenient to apply a coarse-grained computational approach, where the protein is described only by the backbone and the force field only exploits the information contained in the native state (in the spirit of Gō-like models, or native-centric models). The αHL-like pore is portrayed as two coaxial confining cylinders: a larger one for the vestibule and a narrower one for the barrel (or stem). Such simplified approach allows a large number of translocation events to be collected by limited computational resources. The co-translocational unfolding of Ubq is described via a few collective variables that characterize the translocation progress. We find two translocation intermediates (stalled conformations) that can be associated with specific unfolding stages. In particular, in the earliest step, the strand S5 unfolds and enters the pore. This step splits the native conformation into two structural clusters packing against each other in the Ubq fold. A second stall occurs when the hairpin of the N terminal engages the stem region.
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Affiliation(s)
- Fabio Cecconi
- Istituto dei Sistemi Complessi (CNR), Via Taurini 19, I-00185 Roma, Italy
| | - Mauro Chinappi
- Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Roma I-00133, Italy
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14
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Si W, Sha J, Sun Q, He Z, Wu L, Chen C, Yu S, Chen Y. Shape characterization and discrimination of single nanoparticles using solid-state nanopores. Analyst 2020; 145:1657-1666. [PMID: 31922169 DOI: 10.1039/c9an01889a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Resistive pulse sensing with nanopores is expected to enable identification and analysis of nanoscale objects in ionic solutions. However, there is currently no remarkable method to characterize the three-dimensional shape of charged biomolecules or nanoparticles with low-cost and high-throughput. Here we demonstrate the sensing capability of solid-state nanopores for shape characterization of single nanoparticles by monitoring the ionic current blockades during their electrophoretic translocation through nanopores. By using nanopores that are a bit larger than the particles, shape characterization of both spherical and cubic silver nanoparticles is successfully realized due to their rapid rotation with respect to the pore axis, which is further validated by our all-atom molecular dynamics simulations. The single-molecule approach based on nanopores will allow people to measure the dimension and to characterize the shape of single nanoparticles or proteins simultaneously in real time, which is significant for its potential application in investigation of structural biology and proteomics in the near future.
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Affiliation(s)
- Wei Si
- School of Mechanical Engineering, Southeast University, Nanjing 211189, China.
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15
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Ionic transport through a protein nanopore: a Coarse-Grained Molecular Dynamics Study. Sci Rep 2019; 9:15740. [PMID: 31673049 PMCID: PMC6823379 DOI: 10.1038/s41598-019-51942-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 07/17/2019] [Indexed: 11/09/2022] Open
Abstract
The MARTINI coarse-grained (CG) force field is used to test the ability of CG models to simulate ionic transport through protein nanopores. The ionic conductivity of CG ions in solution was computed and compared with experimental results. Next, we studied the electrostatic behavior of a solvated CG lipid bilayer in salt solution under an external electric field. We showed this approach correctly describes the experimental conditions under a potential bias. Finally, we performed CG molecular dynamics simulations of the ionic transport through a protein nanopore (α-hemolysin) inserted in a lipid bilayer, under different electric fields, for 2-3 microseconds. The resulting I - V curve is qualitatively consistent with experiments, although the computed current is one order of magnitude smaller. Current saturation was observed for potential biases over ±350 mV. We also discuss the time to reach a stationary regime and the role of the protein flexibility in our CG simulations.
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16
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Ding T, Chen AK, Lu Z. The applications of nanopores in studies of proteins. Sci Bull (Beijing) 2019; 64:1456-1467. [PMID: 36659703 DOI: 10.1016/j.scib.2019.07.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/07/2019] [Accepted: 05/28/2019] [Indexed: 01/21/2023]
Abstract
Nanopores are a label-free platform with the ability to detect subtle changes in the activities of individual biomolecules under physiological conditions. Here, we comprehensively review the technological development of nanopores, focusing on their applications in studying the physicochemical properties and dynamic conformations of peptides, individual proteins, protein-protein complexes and protein-DNA complexes. This is followed by a brief discussion of the potential challenges that need to be overcome before the technology can be widely accepted by the scientific community. We believe that with continued refinement of the technology, significant understanding can be gained to help clarify the role of protein activities in the regulation of cellular physiology and pathogenesis.
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Affiliation(s)
- Taoli Ding
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China
| | - Antony K Chen
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Zuhong Lu
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China; State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
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17
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Zollo G, Rossini AE. Vibration assisted electron tunneling through nano-gaps in graphene nano-ribbons for amino-acid and peptide bond recognition. NANOSCALE ADVANCES 2019; 1:3547-3554. [PMID: 36133549 PMCID: PMC9417285 DOI: 10.1039/c9na00396g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 07/16/2019] [Indexed: 06/15/2023]
Abstract
Peptide bond and amino-acid recognition by tunneling current flowing across nano-gaps of graphene nano-ribbons has been recently discussed. Theoretical predictions of the tunneling current signals were used in the elastic regime showing peculiar fingerprints. However, inelastic scattering due to vibrations is expected to play an important role. Then, the proposed strategy for peptide sequencing and amino-acid recognition is revised in the light of such inelastic scattering phenomena. Phonon and local vibrational mode assisted current tunneling is calculated by treating electron-phonon scattering in the context of the lowest order expansion of the self-consistent Born approximation. We study Gly and Ala homo-peptides as an example of very similar, small and neutral amino-acids that would be indistinguishable by means of standard techniques, such as the ionic blockade current, in real peptides. We show that all the inelastic contributions to the tunneling current are in the bias range 0 V ≤ V ≤ 0.5 V and that they can be classified, from an atomistic point of view, in terms of energy sub-ranges that they belong to. Peculiar fingerprints can be found for the typical configurations that have been recently found for peptide bond recognition by tunneling current.
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Affiliation(s)
- Giuseppe Zollo
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria (Sezione di Fisica), Università di Roma "La Sapienza" Via A. Scarpa 14-16 00161 Rome Italy
| | - Aldo Eugenio Rossini
- Dipartimento di Scienze di Base e Applicate per l'Ingegneria (Sezione di Fisica), Università di Roma "La Sapienza" Via A. Scarpa 14-16 00161 Rome Italy
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18
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Bonome EL, Cecconi F, Chinappi M. Translocation intermediates of ubiquitin through an α-hemolysin nanopore: implications for detection of post-translational modifications. NANOSCALE 2019; 11:9920-9930. [PMID: 31069350 DOI: 10.1039/c8nr10492a] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanopore based sensors constitute a promising approach to single molecule protein characterization being able, in principle, to detect sequences, structural elements and folding states of proteins and polypeptide chains. In narrow nanopores, one of the open issues concerns the coupling between unfolding and translocation. Here, we studied the ubiquitin translocation in an α-hemolysin nanopore, the most widely used pore for nanopore sensing, via all-atom molecular dynamics simulations. We completely characterize the co-translocational unfolding pathway finding that robust translocation intermediates are associated with the rearrangement of secondary structural elements, as also confirmed by coarse grained simulations. An interesting recurrent pattern is the clogging of the α-hemolysin constriction by an N-terminal β-hairpin. This region of ubiquitin is the target of several post-translational modifications. We propose a strategy to detect post-translational modifications at the N-terminal using the α-hemolysin nanopore based on the comparison of the co-translocational unfolding signals associated with modified and unmodified proteins.
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Affiliation(s)
- Emma Letizia Bonome
- Dipartimento di Ingegneria Meccanica e Aerospaziale Sapienza Università di Roma, Roma, 00185, Italy
| | - Fabio Cecconi
- CNR-Istituto dei Sistemi Complessi UoS Sapienza, Via dei Taurini 19, Roma, 00185, Italy
| | - Mauro Chinappi
- Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Roma, 00133, Italy.
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19
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Insights into protein sequencing with an α-Hemolysin nanopore by atomistic simulations. Sci Rep 2019; 9:6440. [PMID: 31015503 PMCID: PMC6478933 DOI: 10.1038/s41598-019-42867-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 03/25/2019] [Indexed: 12/12/2022] Open
Abstract
Single molecule protein sequencing would represent a disruptive burst in proteomic research with important biomedical impacts. Due to their success in DNA sequencing, nanopore based devices have been recently proposed as possible tools for the sequencing of peptide chains. One of the open questions in nanopore protein sequencing concerns the ability of such devices to provide different signals for all the 20 standard amino acids. Here, using equilibrium all-atom molecular dynamics simulations, we estimated the pore clogging in α-Hemolysin nanopore associated to 20 different homopeptides, one for each standard amino acid. Our results show that pore clogging is affected by amino acid volume, hydrophobicity and net charge. The equilibrium estimations are also supported by non-equilibrium runs for calculating the current blockades for selected homopeptides. Finally, we discuss the possibility to modify the α-Hemolysin nanopore, cutting a portion of the barrel region close to the trans side, to reduce spurious signals and, hence, to enhance the sensitivity of the nanopore.
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20
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Si W, Liu C, Sha J, Zhang Y, Chen Y. Computational modeling of ionic currents through difform graphene nanopores with consistent cross-sectional areas. Phys Chem Chem Phys 2019; 21:26166-26174. [DOI: 10.1039/c9cp05459f] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Unveiling the mystery of ion transport behavior in nanopores with consistent cross-sectional areas shows that this behavior is highly related to the geometry and hydrophobicity of the nanopores.
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Affiliation(s)
- Wei Si
- School of Mechanical Engineering
- Southeast University
- Nanjing 211189
- China
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments
| | - Chenhan Liu
- School of Mechanical Engineering
- Southeast University
- Nanjing 211189
- China
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments
| | - Jingjie Sha
- School of Mechanical Engineering
- Southeast University
- Nanjing 211189
- China
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments
| | - Yin Zhang
- School of Mechanical Engineering
- Southeast University
- Nanjing 211189
- China
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments
| | - Yunfei Chen
- School of Mechanical Engineering
- Southeast University
- Nanjing 211189
- China
- Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments
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21
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Diederichs T, Nguyen QH, Urban M, Tampé R, Tornow M. Transparent Nanopore Cavity Arrays Enable Highly Parallelized Optical Studies of Single Membrane Proteins on Chip. NANO LETTERS 2018; 18:3901-3910. [PMID: 29741381 DOI: 10.1021/acs.nanolett.8b01252] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Membrane proteins involved in transport processes are key targets for pharmaceutical research and industry. Despite continuous improvements and new developments in the field of electrical readouts for the analysis of transport kinetics, a well-suited methodology for high-throughput characterization of single transporters with nonionic substrates and slow turnover rates is still lacking. Here, we report on a novel architecture of silicon chips with embedded nanopore microcavities, based on a silicon-on-insulator technology for high-throughput optical readouts. Arrays containing more than 14 000 inverted-pyramidal cavities of 50 femtoliter volumes and 80 nm circular pore openings were constructed via high-resolution electron-beam lithography in combination with reactive ion etching and anisotropic wet etching. These cavities feature both, an optically transparent bottom and top cap. Atomic force microscopy analysis reveals an overall extremely smooth chip surface, particularly in the vicinity of the nanopores, which exhibits well-defined edges. Our unprecedented transparent chip design provides parallel and independent fluorescent readout of both cavities and buffer reservoir for unbiased single-transporter recordings. Spreading of large unilamellar vesicles with efficiencies up to 96% created nanopore-supported lipid bilayers, which are stable for more than 1 day. A high lipid mobility in the supported membrane was determined by fluorescent recovery after photobleaching. Flux kinetics of α-hemolysin were characterized at single-pore resolution with a rate constant of 0.96 ± 0.06 × 10-3 s-1. Here, we deliver an ideal chip platform for pharmaceutical research, which features high parallelism and throughput, synergistically combined with single-transporter resolution.
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Affiliation(s)
- Tim Diederichs
- Institute of Biochemistry, Biocenter , Goethe University Frankfurt , Max-von-Laue-Str. 9 , 60438 Frankfurt/M. , Germany
| | - Quoc Hung Nguyen
- Molecular Electronics , Technical University of Munich , Theresienstrasse 90 , 80333 Munich , Germany
| | - Michael Urban
- Institute of Biochemistry, Biocenter , Goethe University Frankfurt , Max-von-Laue-Str. 9 , 60438 Frankfurt/M. , Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter , Goethe University Frankfurt , Max-von-Laue-Str. 9 , 60438 Frankfurt/M. , Germany
- Cluster of Excellence Frankfurt (CEF) Macromolecular Complexes ; Goethe University Frankfurt , Max-von-Laue-Strasse 9 , 60438 Frankfurt/M. , Germany
| | - Marc Tornow
- Molecular Electronics , Technical University of Munich , Theresienstrasse 90 , 80333 Munich , Germany
- Fraunhofer Research Institution for Microsystems and Solid State Technologies (EMFT) , Hansastrasse 27d , 80686 Munich , Germany
- Center for NanoScience (CeNS) , Ludwig-Maximilians-University , Geschwister-Scholl Platz 1 , 80539 Munich , Germany
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22
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Chinappi M, Cecconi F. Protein sequencing via nanopore based devices: a nanofluidics perspective. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:204002. [PMID: 29595524 DOI: 10.1088/1361-648x/aababe] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Proteins perform a huge number of central functions in living organisms, thus all the new techniques allowing their precise, fast and accurate characterization at single-molecule level certainly represent a burst in proteomics with important biomedical impact. In this review, we describe the recent progresses in the developing of nanopore based devices for protein sequencing. We start with a critical analysis of the main technical requirements for nanopore protein sequencing, summarizing some ideas and methodologies that have recently appeared in the literature. In the last sections, we focus on the physical modelling of the transport phenomena occurring in nanopore based devices. The multiscale nature of the problem is discussed and, in this respect, some of the main possible computational approaches are illustrated.
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Affiliation(s)
- Mauro Chinappi
- Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, via del Politecnico 1, 00133 Roma, Italy
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23
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Zhang Q, Lin J, Wang L, Xu Z. Theoretical modeling and simulations of self-assembly of copolymers in solution. Prog Polym Sci 2017. [DOI: 10.1016/j.progpolymsci.2017.04.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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24
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Desikan R, Maiti PK, Ayappa KG. Assessing the Structure and Stability of Transmembrane Oligomeric Intermediates of an α-Helical Toxin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:11496-11510. [PMID: 28930630 DOI: 10.1021/acs.langmuir.7b02277] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Protein membrane interactions play an important role in our understanding of diverse phenomena ranging from membrane-assisted protein aggregation to oligomerization and folding. Pore-forming toxins (PFTs) are the primary vehicle for infection by several strains of bacteria. These proteins which are expressed in a water-soluble form (monomers) bind to the target membrane and conformationally transform (protomers) and self-assemble to form a multimer transmembrane pore complex through a process of oligomerization. On the basis of the structure of the transmembrane domains, PFTs are broadly classified into β or α toxins. In contrast to β-PFTs, the paucity of available crystal structures coupled with the amphipathic nature of the transmembrane domains has hindered our understanding of α-PFT pore formation. In this article, we use molecular dynamics (MD) simulations to examine the process of pore formation of the bacterial α-PFT, cytolysin A from Escherichia coli (ClyA) in lipid bilayer membranes. Using atomistic MD simulations ranging from 50 to 500 ns, we show that transmembrane oligomeric intermediates or "arcs" form stable proteolipidic complexes consisting of protein arcs with toroidal lipids lining the free edges. By creating initial conditions where the lipids are contained within the arcs, we study the dynamics of spontaneous lipid evacuation and toroidal edge formation. This process occurs on the time scale of tens of nanoseconds, suggesting that once protomers oligomerize, transmembrane arcs are rapidly stabilized to form functional water channels capable of leakage. Using umbrella sampling with a coarse-grained molecular model, we obtain the free energy of insertion of a single protomer into the membrane. A single inserted protomer has a stabilization free energy of -52.9 ± 1.2 kJ/mol and forms a stable transmembrane water channel capable of leakage. Our simulations reveal that arcs are stable and viable intermediates that can occur during the pore-formation pathway for ClyA.
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Affiliation(s)
- Rajat Desikan
- Department of Chemical Engineering, ‡Centre for Condensed Matter Theory, Department of Physics, and §Centre for Biosystems Science and Engineering, Indian Institute of Science , Bengaluru, India 560012
| | - Prabal K Maiti
- Department of Chemical Engineering, ‡Centre for Condensed Matter Theory, Department of Physics, and §Centre for Biosystems Science and Engineering, Indian Institute of Science , Bengaluru, India 560012
| | - K Ganapathy Ayappa
- Department of Chemical Engineering, ‡Centre for Condensed Matter Theory, Department of Physics, and §Centre for Biosystems Science and Engineering, Indian Institute of Science , Bengaluru, India 560012
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25
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Watanabe H, Gubbiotti A, Chinappi M, Takai N, Tanaka K, Tsumoto K, Kawano R. Analysis of Pore Formation and Protein Translocation Using Large Biological Nanopores. Anal Chem 2017; 89:11269-11277. [DOI: 10.1021/acs.analchem.7b01550] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Hirokazu Watanabe
- Department
of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Alberto Gubbiotti
- Department
of Mechanical and Aerospace Engineering, Sapienza University of Rome, Via Eudossiana 18, Rome 00184, Italy
| | - Mauro Chinappi
- Department
of Industrial Engineering, University of Rome Tor Vergata, Via
del Politecnico 1, Rome 00133, Italy
| | - Natsumi Takai
- Department
of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Koji Tanaka
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kouhei Tsumoto
- Department
of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Ryuji Kawano
- Department
of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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26
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Desikan R, Patra SM, Sarthak K, Maiti PK, Ayappa KG. Comparison of coarse-grained (MARTINI) and atomistic molecular dynamics simulations of $$\alpha $$ α and $$\beta $$ β toxin nanopores in lipid membranes. J CHEM SCI 2017. [DOI: 10.1007/s12039-017-1316-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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27
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Cecconi F, Shahzad MA, Marini Bettolo Marconi U, Vulpiani A. Frequency-control of protein translocation across an oscillating nanopore. Phys Chem Chem Phys 2017; 19:11260-11272. [DOI: 10.1039/c6cp08156h] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The translocation of a lipid binding protein (LBP) is studied using a phenomenological coarse-grained computational model that simplifies both chain and pore geometry.
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Affiliation(s)
| | | | | | - Angelo Vulpiani
- Dipartimento di Fisica
- Università “Sapienza” di Roma
- Italy
- Centro Linceo Interdisciplinare “B. Segre”
- Accademia dei Lincei
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28
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Asandei A, Schiopu I, Chinappi M, Seo CH, Park Y, Luchian T. Electroosmotic Trap Against the Electrophoretic Force Near a Protein Nanopore Reveals Peptide Dynamics During Capture and Translocation. ACS APPLIED MATERIALS & INTERFACES 2016; 8:13166-79. [PMID: 27159806 DOI: 10.1021/acsami.6b03697] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report on the ability to control the dynamics of a single peptide capture and passage across a voltage-biased, α-hemolysin nanopore (α-HL), under conditions that the electroosmotic force exerted on the analyte dominates the electrophoretic transport. We demonstrate that by extending outside the nanopore, the electroosmotic force is able to capture a peptide at either the lumen or vestibule entry of the nanopore, and transiently traps it inside the nanopore, against the electrophoretic force. Statistical analysis of the resolvable dwell-times of a metastable trapped peptide, as it occupies either the β-barrel or vestibule domain of the α-HL nanopore, reveals rich kinetic details regarding the direction and rates of stochastic movement of a peptide inside the nanopore. The presented approach demonstrates the ability to shuttle and study molecules along the passage pathway inside the nanopore, allows to identify the mesoscopic trajectory of a peptide exiting the nanopore through either the vestibule or β-barrel moiety, thus providing convincing proof of a molecule translocating the pore. The kinetic analysis of a peptide fluctuating between various microstates inside the nanopore, enabled a detailed picture of the free energy description of its interaction with the α-HL nanopore. When studied at the limit of vanishingly low transmembrane potentials, this provided a thermodynamic description of peptide reversible binding to and within the α-HL nanopore, under equilibrium conditions devoid of electric and electroosmotic contributions.
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Affiliation(s)
- Alina Asandei
- Department of Interdisciplinary Research, Alexandru I. Cuza University , Iasi 700506, Romania
| | - Irina Schiopu
- Department of Interdisciplinary Research, Alexandru I. Cuza University , Iasi 700506, Romania
| | - Mauro Chinappi
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia , Roma, Viale Regina Elena 291, 00161 , Italy
| | - Chang Ho Seo
- Department of Bioinformatics, Kongju National University , Kongju 314-701, South Korea
| | - Yoonkyung Park
- Department of Biomedical Science and Research Center for Proteineous Materials, Chosun University , Gwangju 61452, South Korea
| | - Tudor Luchian
- Department of Physics, Alexandru I. Cuza University , Iasi 700506, Romania
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29
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Tan S, Gu D, Liu H, Liu Q. Detection of a single enzyme molecule based on a solid-state nanopore sensor. NANOTECHNOLOGY 2016; 27:155502. [PMID: 26937593 DOI: 10.1088/0957-4484/27/15/155502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The nanopore sensor as a high-throughput and low-cost technology can detect a single molecule in a solution. In the present study, relatively large silicon nitride (Si3N4) nanopores with diameters of ∼28 and ∼88 nm were fabricated successfully using a focused Ga ion beam. We have used solid-state nanopores with various sizes to detect the single horseradish peroxidase (HRP) molecule and for the first time analyzed single HRP molecular translocation events. In addition, a real-time monitored single enzyme molecular biochemical reaction and a translocation of the product of enzyme catalysis substrates were investigated by using a Si3N4 nanopore. Our nanopore system showed a high sensitivity in detecting single enzyme molecules and a real-time monitored single enzyme molecular biochemical reaction. This method could also be significant for studying gene expression or enzyme dynamics at the single-molecule level.
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Affiliation(s)
- ShengWei Tan
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, No. 2, Sipailou, Nanjing 210096, People's Republic of China
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30
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Chandramouli B, Di Maio D, Mancini G, Brancato G. Introducing an artificial photo-switch into a biological pore: A model study of an engineered α-hemolysin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:689-97. [DOI: 10.1016/j.bbamem.2015.12.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 12/06/2015] [Accepted: 12/24/2015] [Indexed: 12/21/2022]
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31
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Ansalone P, Chinappi M, Rondoni L, Cecconi F. Driven diffusion against electrostatic or effective energy barrier across α-hemolysin. J Chem Phys 2015; 143:154109. [DOI: 10.1063/1.4933012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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32
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Chinappi M, Luchian T, Cecconi F. Nanopore tweezers: voltage-controlled trapping and releasing of analytes. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:032714. [PMID: 26465505 DOI: 10.1103/physreve.92.032714] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Indexed: 05/28/2023]
Abstract
Several devices for single-molecule detection and analysis employ biological and artificial nanopores as core elements. The performance of such devises strongly depends on the amount of time the analytes spend into the pore. This residence time needs to be long enough to allow the recording of a high signal-to-noise ratio analyte-induced blockade. We propose a simple approach, dubbed nanopore tweezing, for enhancing the trapping time of molecules inside the pore via a proper tuning of the applied voltage. This method requires the creation of a strong dipole that can be generated by adding a positive and a negative tail at the two ends of the molecules to be analyzed. Capture rate is shown to increase with the applied voltage while escape rate decreases. In this paper we rationalize the essential ingredients needed to control the residence time and provide a proof of principle based on atomistic simulations.
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Affiliation(s)
- Mauro Chinappi
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, Via Regina Elena 291, 00161 Roma, Italia
| | - Tudor Luchian
- Department of Physics, Laboratory of Molecular Biophysics and Medical Physics, Alexandru I. Cuza University, Iasi 700506, Romania
| | - Fabio Cecconi
- CNR-Istituto dei Sistemi Complessi UoS "Sapienza," Via dei Taurini 19, 00185 Roma (Italy)
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