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Baldelli M, Di Muccio G, Sauciuc A, Morozzo Della Rocca B, Viola F, Balme S, Bonini A, Maglia G, Chinappi M. Controlling Electroosmosis in Nanopores Without Altering the Nanopore Sensing Region. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024:e2401761. [PMID: 38860821 DOI: 10.1002/adma.202401761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/24/2024] [Indexed: 06/12/2024]
Abstract
Nanopores are powerful tools for single-molecule sensing of biomolecules and nanoparticles. The signal coming from the molecule to be analyzed strongly depends on its interaction with the narrower section of the nanopore (constriction) that may be tailored to increase sensing accuracy. Modifications of nanopore constriction have also been commonly used to induce electroosmosis, that favors the capture of molecules in the nanopore under a voltage bias and independently of their charge. However, engineering nanopores for increasing both electroosmosis and sensing accuracy is challenging. Here it is shown that large electroosmotic flows can be achieved without altering the nanopore constriction. Using continuum electrohydrodynamic simulations, it is found that an external charged ring generates strong electroosmosis in cylindrical nanopores. Similarly, for conical nanopores it is shown that moving charges away from the cone tip still results in an electroosmotic flow (EOF), whose intensity reduces increasing the diameter of the nanopore section where charges are placed. This paradigm is applied to engineered biological nanopores showing, via atomistic simulations and experiments, that mutations outside the constriction induce a relatively intense electroosmosis. This strategy provides much more flexibility in nanopore design since electroosmosis can be controlled independently from the constriction, which can be optimized to improve sensing accuracy.
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Affiliation(s)
- Matteo Baldelli
- Department of Industrial Engeenering, University of Rome Tor Vergata, Roma, 00133, Italy
| | - Giovanni Di Muccio
- Department of Mechanical and Aerospace Engineering, University of Rome Sapienza, Roma, 00184, Italy
| | - Adina Sauciuc
- Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen, 9747 AG, The Netherlands
| | | | | | - Sébastien Balme
- Institut Europeen des Membranes, UMR5635, University of Montpellier ENCSM CNRS, Montpellier, 34095, France
| | - Andrea Bonini
- Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen, 9747 AG, The Netherlands
| | - Giovanni Maglia
- Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Groningen, 9747 AG, The Netherlands
| | - Mauro Chinappi
- Department of Industrial Engeenering, University of Rome Tor Vergata, Roma, 00133, Italy
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2
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Mereuta L, Asandei A, Andricioaei I, Park J, Park Y, Luchian T. Considerable slowdown of short DNA fragment translocation across a protein nanopore using pH-induced generation of enthalpic traps inside the permeation pathway. NANOSCALE 2023; 15:14754-14763. [PMID: 37655668 DOI: 10.1039/d3nr03344a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
A pressing challenge in the realm of nanopore-based sensing technologies for nucleic acid characterization has been the cheap and efficient control of analyte translocation. To address this, a plethora of methods were tested, including mutagenesis, molecular motors, enzymes, or the optimization of experimental conditions. Herein, we present a paradigm exploiting the manipulation of electrostatic interactions between 22-mer single-stranded DNAs (22_ssDNA) and low pH-induced charges in the alpha-hemolysin (α-HL) nanopore, to efficiently control the passage of captured molecules. We discovered that in electrolytes buffered at pH = 5 and pH = 4.5 where the nanopore's vestibule and lumen become oppositely charged as compared to that at neutral pH, the electrostatic anchoring at these regions of a 22_ssDNA fragment leads to a dramatic increase of the translocation time, orders of magnitude larger compared to that at neutral pH. This pH-dependent tethering effect is reversible, side invariant, and sensitive to the ionic strength and ssDNA contour length. In the long run, our discovery has the potential to provide a simple read-out of the sequence of bases pertaining to short nucleotide sequences, thus extending the efficacy of current nanopore-based sequencers.
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Affiliation(s)
- Loredana Mereuta
- Department of Physics, Alexandru I. Cuza University, 700506 Iasi, Romania.
| | - Alina Asandei
- Interdisciplinary Research Institute, Sciences Department, Alexandru I. Cuza University, 700506 Iasi, Romania
| | - Ioan Andricioaei
- Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, CA 92617, USA
| | - Jonggwan Park
- Department of Bioinformatics, Kongju National University, Kongju, 32588, Republic of Korea
| | - Yoonkyung Park
- Department of Biomedical Science and Research Center for Proteinaceous Materials (RCPM), Chosun University, Gwangju, 61452, Republic of Korea.
| | - Tudor Luchian
- Department of Physics, Alexandru I. Cuza University, 700506 Iasi, Romania.
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Zhou G, Wang Q, Wang Y, Wen X, Peng H, Peng R, Shi Q, Xie X, Li L. Outer Membrane Porins Contribute to Antimicrobial Resistance in Gram-Negative Bacteria. Microorganisms 2023; 11:1690. [PMID: 37512863 PMCID: PMC10385648 DOI: 10.3390/microorganisms11071690] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Gram-negative bacteria depend on their cell membranes for survival and environmental adaptation. They contain two membranes, one of which is the outer membrane (OM), which is home to several different outer membrane proteins (Omps). One class of important Omps is porins, which mediate the inflow of nutrients and several antimicrobial drugs. The microorganism's sensitivity to antibiotics, which are predominantly targeted at internal sites, is greatly influenced by the permeability characteristics of porins. In this review, the properties and interactions of five common porins, OmpA, OmpC, OmpF, OmpW, and OmpX, in connection to porin-mediated permeability are outlined. Meanwhile, this review also highlighted the discovered regulatory characteristics and identified molecular mechanisms in antibiotic penetration through porins. Taken together, uncovering porins' functional properties will pave the way to investigate effective agents or approaches that use porins as targets to get rid of resistant gram-negative bacteria.
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Affiliation(s)
- Gang Zhou
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qian Wang
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yingsi Wang
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xia Wen
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Hong Peng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Ruqun Peng
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Qingshan Shi
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Xiaobao Xie
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Liangqiu Li
- Key Laboratory of Agricultural Microbiomics and Precision Application (MARA), Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Key Laboratory of Agricultural Microbiome (MARA), State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
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Fauvel M, Trybala A, Tseluiko D, Starov VM, Bandulasena HCH. Foam-Based Electrophoretic Separation of Charged Dyes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:13935-13942. [PMID: 36322953 PMCID: PMC9671044 DOI: 10.1021/acs.langmuir.2c02228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Electrophoretic separation of a fluorescent dye mixture, containing rhodamine B (RB) and fluorescein, in liquid foams stabilized by anionic, cationic, or non-ionic surfactants in water-glycerol mixtures was studied in a custom-designed foam separation device. The effects of the external electric field applied across the foam and the initial pH of the solution on the effectiveness of separation were also studied. The fluid motion due to electroosmosis and the resulting back pressure within the foam and local pH changes were found to be complex and affected the separation. Fluorescein dye molecules, which have a positive or negative charge depending on the solution pH, aggregated in the vicinity of an electrode, leaving a pure band of neutral dye RB. The effectiveness of the separation was quantified by the percentage width of the pure RB band, which was found to be between 29 and 42%. This study demonstrates the potential of liquid foam as a platform for electrophoretic separation.
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Affiliation(s)
- Matthieu Fauvel
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Anna Trybala
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Dmitri Tseluiko
- Department
of Mathematics, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
| | - Victor Mikhilovich Starov
- Department
of Chemical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU, U.K.
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Prajapati JD, Pangeni S, Aksoyoglu MA, Winterhalter M, Kleinekathöfer U. Changes in Salt Concentration Modify the Translocation of Neutral Molecules through a ΔCymA Nanopore in a Non-monotonic Manner. ACS NANO 2022; 16:7701-7712. [PMID: 35435659 DOI: 10.1021/acsnano.1c11471] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The voltage-dependent transport through biological and artificial nanopores is being used in many applications such as DNA or protein sequencing and sensing. The primary approach to determine the transport has been to measure the temporal ion current fluctuations caused by solutes when applying external voltages. Crossing the nanoscale confinement in the presence of an applied electric field primarily relies on two factors, i.e., the electrophoretic drag and electroosmosis. The electroosmotic flow (EOF) is a voltage-dependent ion-associated flow of solvent molecules, i.e., usually water, and depends on many factors, such as pH, temperature, pore diameter, and also the concentration of ions. The exact interplay between these factors is so far poorly understood. In this joint experimental and computational study, we have investigated the dependence of the EOF on the concentration of the buffer salt by probing the transport of α-cyclodextrin molecules through the ΔCymA channel. For five different KCl concentrations in the range between 0.125 and 2 M, we performed applied-field molecular dynamics simulations and analyzed the ionic flow and the EOF across the ΔCymA pore. To our surprise, the concentration-dependent net ionic flux changes non-monotonically and nonlinearly and the EOF is seen to follow the same pattern. On the basis of these findings, we were able to correlate the concentration-dependent EOF with experimental kinetic constants for the translocation of α-cyclodextrin through the ΔCymA nanopore. Overall, the results further improve our understanding of the EOF-mediated transport through nanopores and show that the EOF needs to seriously be taken into consideration when analyzing the permeation of (neutral) substrates through nanopores.
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Affiliation(s)
| | - Sushil Pangeni
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759 Bremen, Germany
| | | | - Mathias Winterhalter
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany
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Suginta W, Sanram S, Aunkham A, Winterhalter M, Schulte A. The C2 entity of chitosugars is crucial in molecular selectivity of the Vibrio campbellii chitoporin. J Biol Chem 2021; 297:101350. [PMID: 34715124 PMCID: PMC8608610 DOI: 10.1016/j.jbc.2021.101350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/21/2021] [Accepted: 10/22/2021] [Indexed: 12/14/2022] Open
Abstract
The marine bacterium Vibrio campbellii expresses a chitooligosaccharide-specific outer-membrane channel (chitoporin) for the efficient uptake of nutritional chitosugars that are externally produced through enzymic degradation of environmental host shell chitin. However, the principles behind the distinct substrate selectivity of chitoporins are unclear. Here, we employed black lipid membrane (BLM) electrophysiology, which handles the measurement of the flow of ionic current through porins in phospholipid bilayers for the assessment of porin conductivities, to investigate the pH dependency of chitosugar-chitoporin interactions for the bacterium's natural substrate chitohexaose and its deacetylated form, chitosan hexaose. We show that efficient passage of the N-acetylated chitohexaose through the chitoporin is facilitated by its strong affinity for the pore. In contrast, the deacetylated chitosan hexaose is impermeant; however, protonation of the C2 amino entities of chitosan hexaose allows it to be pulled through the channel in the presence of a transmembrane electric field. We concluded from this the crucial role of C2-substitution as the determining factor for chitoporin entry. A change from N-acetylamino- to amino-substitution effectively abolished the ability of approaching molecules to enter the chitoporin, with deacetylation leading to loss of the distinctive structural features of nanopore opening and pore access of chitosugars. These findings provide further understanding of the multistep pathway of chitin utilization by marine Vibrio bacteria and may guide the development of solid-state or genetically engineered biological nanopores for relevant technological applications.
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Affiliation(s)
- Wipa Suginta
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
| | - Surapoj Sanram
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Anuwat Aunkham
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Mathias Winterhalter
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Albert Schulte
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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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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Winterhalter M. Antibiotic uptake through porins located in the outer membrane of Gram-negative bacteria. Expert Opin Drug Deliv 2020; 18:449-457. [PMID: 33161750 DOI: 10.1080/17425247.2021.1847080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Introduction: Making selective inhibitors of novel Gram-negative targets is not a substantial challenge - getting them into Gram-negative bacteria to reach their lethal target is the bottleneck. Poor permeability of the antibiotic requires high concentration causing off target activity. The lack of simple experimental techniques to measure antibiotic uptake as well as the local concentration at the target site creates a particular bottleneck in understanding and in improving the antibiotic activity.Areas covered: Here we recall current approaches to quantify the uptake. For a few antibiotics with known evidence for channel-limited permeation, the flux across a single OmpF or OmpC channel has been measured. For a typical concentration gradient of 1 µM of antibiotics the uptake varies between one up to few hundred molecules per second and per channel.Expert opinion: The current research effort is on quantifying the flux for a larger list of compounds on a cellular (mass spectra, fluorescence) or at single channel level (electrophysiology). A larger dataset of single channel permeabilities under various condition will be a powerful tool for understanding and improving the activity of antibiotics.
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Prajapati JD, Mele C, Aksoyoglu MA, Winterhalter M, Kleinekathöfer U. Computational Modeling of Ion Transport in Bulk and through a Nanopore Using the Drude Polarizable Force Field. J Chem Inf Model 2020; 60:3188-3203. [DOI: 10.1021/acs.jcim.0c00389] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
| | - Crystal Mele
- Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany
| | | | - Mathias Winterhalter
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, 28759 Bremen, Germany
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