1
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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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2
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Stoorza AM, Duerfeldt AS. Guiding the Way: Traditional Medicinal Chemistry Inspiration for Rational Gram-Negative Drug Design. J Med Chem 2024; 67:65-80. [PMID: 38134355 PMCID: PMC11342810 DOI: 10.1021/acs.jmedchem.3c01831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
The discovery and development of small-molecule therapeutics effective against Gram-negative pathogens are highly challenging tasks. Most compounds that are active in biochemical settings fail to exhibit whole-cell activity. The major reason for this lack of activity is the effectiveness of bacterial cell envelopes as permeability barriers. These barriers originate from the nutrient-selective outer membranes, which act synergistically with polyspecific efflux pumps. Guiding principles to enable rational optimization of small molecules for efficient penetration and intracellular accumulation in Gram-negative bacteria would have a transformative impact on the discovery and design of chemical probes and therapeutics. In this Perspective, we draw on inspiration from traditional medicinal chemistry approaches for eukaryotic drug design to present a broader call for action in developing comparable approaches for Gram-negative bacteria.
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Affiliation(s)
- Alexis M Stoorza
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55414, United States
| | - Adam S Duerfeldt
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota 55414, United States
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3
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Berezhkovskii AM, Bezrukov SM. Counter-Intuitive Features of Particle Dynamics in Nanopores. Int J Mol Sci 2023; 24:15923. [PMID: 37958906 PMCID: PMC10648703 DOI: 10.3390/ijms242115923] [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: 09/22/2023] [Revised: 10/27/2023] [Accepted: 10/29/2023] [Indexed: 11/15/2023] Open
Abstract
Using the framework of a continuous diffusion model based on the Smoluchowski equation, we analyze particle dynamics in the confinement of a transmembrane nanopore. We briefly review existing analytical results to highlight consequences of interactions between the channel nanopore and the translocating particles. These interactions are described within a minimalistic approach by lumping together multiple physical forces acting on the particle in the pore into a one-dimensional potential of mean force. Such radical simplification allows us to obtain transparent analytical results, often in a simple algebraic form. While most of our findings are quite intuitive, some of them may seem unexpected and even surprising at first glance. The focus is on five examples: (i) attractive interactions between the particles and the nanopore create a potential well and thus cause the particles to spend more time in the pore but, nevertheless, increase their net flux; (ii) if the potential well-describing particle-pore interaction occupies only a part of the pore length, the mean translocation time is a non-monotonic function of the well length, first increasing and then decreasing with the length; (iii) when a rectangular potential well occupies the entire nanopore, the mean particle residence time in the pore is independent of the particle diffusivity inside the pore and depends only on its diffusivity in the bulk; (iv) although in the presence of a potential bias applied to the nanopore the "downhill" particle flux is higher than the "uphill" one, the mean translocation times and their distributions are identical, i.e., independent of the translocation direction; and (v) fast spontaneous gating affects nanopore selectivity when its characteristic time is comparable to that of the particle transport through the pore.
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Affiliation(s)
| | - 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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4
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Chen C, Song M, Li K, Yan S, Chen M, Geng J. E. coli outer membrane protein T (OmpT) nanopore for peptide sensing. Biochem Biophys Res Commun 2023; 677:132-140. [PMID: 37586211 DOI: 10.1016/j.bbrc.2023.05.125] [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: 04/24/2023] [Accepted: 05/31/2023] [Indexed: 08/18/2023]
Abstract
Peptide detection methods with facility and high sensitivity are essential for diagnosing disease associated with peptide biomarkers. Nanopore sensing technology had emerged as a low cost, high-throughput, and scalable tool for peptide detection. The omptins family proteins which can form β-barrel pores have great potentials to be developed as nanopore biosensor. However, there are no study about the channel properties of E. coli OmpT and the development of OmpT as a nanopore biosensor. In this study, the OmpT biological nanopore channel was constructed with a conductance of 1.49 nS in 500 mM NaCl buffer and a three-step gating phenomenon under negative voltage higher than 100 mV and then was developed as a peptide biosensor which can detect peptide without the interfere of ssDNA and dNTPs. The OmpT constructed in this study has potential application in peptide detection, and also provides a new idea for the detection of peptides using the specific binding ability of protease.
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Affiliation(s)
- Chuan Chen
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China; School of Pharmacy, North Sichuan Medical College, Nanchong, 637000, China
| | - Mengxiao Song
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China
| | - Kaiju Li
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China
| | - Shixin Yan
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China
| | - Mutian Chen
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China
| | - Jia Geng
- Department of Laboratory Medicine, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China; Tianfu Jincheng Laboratory, City of Future Medicine, Chengdu 641400, China.
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5
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Singh U, Singh P, Singh AK, Singh S, Kumar D, Shrivastava SK, Asthana RK. In silico and in vitro evaluation of extract derived from Dunaliella salina, a halotolerant microalga for its antifungal and antibacterial activity. J Biomol Struct Dyn 2023; 41:7069-7083. [PMID: 36017823 DOI: 10.1080/07391102.2022.2115556] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 08/14/2022] [Indexed: 10/15/2022]
Abstract
In the present study little explored halotolerant wall-less green alga Dunaliella salina was found to be a potent source of antibacterial and antifungal biomolecules. Both the target pathogens, bacteria (Escherischia coli, Klebsiella pneumoniae, and Acinetobacter baumannii) and fungi (Candida albicans, C. tropicalis, and Cryptococus sp.) were WHO prioritized. The bioassay guided approach led us to evaluate antibacterial and antifungal lead molecule(s) from an array of compounds using spectroscopic and in silico studies. The methanol derived crude extract was purified via thin layer chromatography (TLC) using solvent system methanol: chloroform (1:19). Maximum antimicrobial activity was observed in fractions D5, D6 and D7, the components of which were then recognized using high resolution-liquid chromatography/mass spectroscopy (Orbitrap) (HR-LC/MS). The screened compounds were then docked with target enzymes sterol-14-alpha demethylase and OmpF porin protein. The energy scores revealed that amongst all, lariciresinol-4-O-glucoside showed better binding affinity, in silico, using the Schrödinger Maestro 2018-1 platform. The 3-dimensional crystal structures of both the proteins were retrieved from the protein data bank (PDB), and showed binding energies of -14.35 kcal/mol, and -11.0 kcal/mol against respective drug targets. The molecular dynamics (MD) simulations were performed for 100 ns, using Desmond package, Schrödinger to evaluate the conformational stability and alteration of protein-ligand complexes during the simulation. Thus, our findings confirmed that lariciresinol-4-O-glucoside, a lignan derivative and known strong antioxidant, may be used as an important "lead" molecule to be developed as antibacterial and antifungal drugs in the future.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Urmilesh Singh
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Prabhakar Singh
- Biochemistry Department, North Eastern Hill University, Shillong, Meghalaya, India
| | - Ankit Kumar Singh
- Department of Botany, Marwari College (a constituent unit of Lalit Narayan Mithila University), Darbhanga, Bihar, India
| | - Sweksha Singh
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Deepak Kumar
- Department of Microbiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Sushant Kumar Shrivastava
- Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ravi Kumar Asthana
- R. N. Singh Memorial Laboratory, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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6
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Donoghue A, Winterhalter M, Gutsmann T. Influence of Membrane Asymmetry on OmpF Insertion, Orientation and Function. MEMBRANES 2023; 13:membranes13050517. [PMID: 37233578 DOI: 10.3390/membranes13050517] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/29/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023]
Abstract
The effect of asymmetric membranes containing lipopolysaccharides (LPS) on the outer membrane protein F (OmpF) reconstitution, channel orientation, and antibiotic permeation across the outer membrane was investigated. After forming an asymmetric planar lipid bilayer composed of LPS on one and phospholipids on the other side, the membrane channel OmpF was added. The ion current recordings demonstrate that LPS has a strong influence on the OmpF membrane insertion, orientation, and gating. Enrofloxacin was used as an example of an antibiotic interacting with the asymmetric membrane and with OmpF. The enrofloxacin caused the blockage of the ion current through the OmpF, depending on the side of addition, the transmembrane voltage applied, and the composition of the buffer. Furthermore, the enrofloxacin changed the phase behavior of the LPS-containing membranes, demonstrating that its membrane activity influences the function of OmpF and potentially the membrane permeability.
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Affiliation(s)
- Annemarie Donoghue
- Research Center Borstel, Leibniz Lung Center, Parkallee 10, 23845 Borstel, Germany
- School of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany
| | | | - Thomas Gutsmann
- Research Center Borstel, Leibniz Lung Center, Parkallee 10, 23845 Borstel, Germany
- Center for Structural Systems Biology, Notkestraße 85, Building 15, 22607 Hamburg, Germany
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7
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Zhang Y, Kepiro I, Ryadnov MG, Pagliara S. Single Cell Killing Kinetics Differentiate Phenotypic Bacterial Responses to Different Antibacterial Classes. Microbiol Spectr 2023; 11:e0366722. [PMID: 36651776 PMCID: PMC9927147 DOI: 10.1128/spectrum.03667-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/19/2022] [Indexed: 01/19/2023] Open
Abstract
With the spread of multidrug-resistant bacteria, there has been an increasing focus on molecular classes that have not yet yielded an antibiotic. A key capability for assessing and prescribing new antibacterial treatments is to compare the effects antibacterial agents have on bacterial growth at a phenotypic, single-cell level. Here, we combined time-lapse microscopy with microfluidics to investigate the concentration-dependent killing kinetics of stationary-phase Escherichia coli cells. We used antibacterial agents from three different molecular classes, β-lactams and fluoroquinolones, with the known antibiotics ampicillin and ciprofloxacin, respectively, and a new experimental class, protein Ψ-capsids. We found that bacterial cells elongated when treated with ampicillin and ciprofloxacin used at their minimum inhibitory concentration (MIC). This was in contrast to Ψ-capsids, which arrested bacterial elongation within the first two hours of treatment. At concentrations exceeding the MIC, all the antibacterial agents tested arrested bacterial growth within the first 2 h of treatment. Further, our single-cell experiments revealed differences in the modes of action of three different agents. At the MIC, ampicillin and ciprofloxacin caused the lysis of bacterial cells, whereas at higher concentrations, the mode of action shifted toward membrane disruption. The Ψ-capsids killed cells by disrupting their membranes at all concentrations tested. Finally, at increasing concentrations, ampicillin and Ψ-capsids reduced the fraction of the population that survived treatment in a viable but nonculturable state, whereas ciprofloxacin increased this fraction. This study introduces an effective capability to differentiate the killing kinetics of antibacterial agents from different molecular classes and offers a high content analysis of antibacterial mechanisms at the single-cell level. IMPORTANCE Antibiotics act against bacterial pathogens by inhibiting their growth or killing them directly. Different modes of action determine different antibacterial responses, whereas phenotypic differences in bacteria can challenge the efficacy of antibiotics. Therefore, it is important to be able to differentiate the concentration-dependent killing kinetics of antibacterial agents at a single-cell level, in particular for molecular classes which have not yielded an antibiotic before. Here, we measured single-cell responses using microfluidics-enabled imaging, revealing that a novel class of antibacterial agents, protein Ψ-capsids, arrests bacterial elongation at the onset of treatment, whereas elongation continues for cells treated with β-lactam and fluoroquinolone antibiotics. The study advances our current understanding of antibacterial function and offers an effective strategy for the comparative design of new antibacterial therapies, as well as clinical antibiotic susceptibility testing.
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Affiliation(s)
- Yuewen Zhang
- Living Systems Institute and Biosciences, University of Exeter, Exeter, United Kingdom
- National Physical Laboratory, Teddington, United Kingdom
| | - Ibolya Kepiro
- National Physical Laboratory, Teddington, United Kingdom
| | - Maxim G. Ryadnov
- National Physical Laboratory, Teddington, United Kingdom
- Department of Physics, King’s College London, London, United Kingdom
| | - Stefano Pagliara
- Living Systems Institute and Biosciences, University of Exeter, Exeter, United Kingdom
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8
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Tennakoon G, Taylor SW. Velocity jump process with volume exclusions in a narrow channel. Phys Rev E 2023; 107:024131. [PMID: 36932568 DOI: 10.1103/physreve.107.024131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
This paper analyzes the impact of collisions in a system of N identical hard-core particles driven according to a velocity jump process. The physical space is essentially a channel in R with a probability of occupants being able to pass each other. The system mimics what nature does, where individuals pass one another in a narrow channel while making incidental contact with those moving in the opposite direction. The passing probability may depend on the particles' size and the channel's width. Starting from the particle level model, we systematically derive a nonlinear transport equation based on an asymptotic expansion. Under low-occupied fractions, numerical solutions of both the kinetic model and the stochastic particle system are compared well during biased and unbiased random velocity changes. Analysis of the subpopulation motility within a large population exhibits the consequences of volume exclusions and channel confinements on the traveling speeds.
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Affiliation(s)
- Gayani Tennakoon
- Department of Mathematics, University of Auckland, Auckland 1010, New Zealand
| | - Stephen W Taylor
- Department of Mathematics, University of Auckland, Auckland 1010, New Zealand
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9
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Emergence and spread of antibiotic-resistant foodborne pathogens from farm to table. Food Sci Biotechnol 2022; 31:1481-1499. [PMID: 36065433 PMCID: PMC9435411 DOI: 10.1007/s10068-022-01157-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/26/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Antibiotics have been overused and misused for preventive and therapeutic purposes. Specifically, antibiotics are frequently used as growth promoters for improving productivity and performance of food-producing animals such as pigs, cattle, and poultry. The increasing use of antibiotics has been of great concern worldwide due to the emergence of antibiotic resistant bacteria. Food-producing animals are considered reservoirs for antibiotic resistance genes (ARGs) and residual antibiotics that transfer from the farm through the table. The accumulation of residual antibiotics can lead to additional antibiotic resistance in bacteria. Therefore, this review evaluates the risk of carriage and spread of antibiotic resistance through food chain and the potential impact of antibiotic use in food-producing animals on food safety. This review also includes in-depth discussion of promising antibiotic alternatives such as vaccines, immune modulators, phytochemicals, antimicrobial peptides, probiotics, and bacteriophages.
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10
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Popella L, Jung J, Do PT, Hayward RJ, Barquist L, Vogel J. Comprehensive analysis of PNA-based antisense antibiotics targeting various essential genes in uropathogenic Escherichia coli. Nucleic Acids Res 2022; 50:6435-6452. [PMID: 35687096 PMCID: PMC9226493 DOI: 10.1093/nar/gkac362] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/05/2022] [Accepted: 06/08/2022] [Indexed: 12/13/2022] Open
Abstract
Antisense peptide nucleic acids (PNAs) that target mRNAs of essential bacterial genes exhibit specific bactericidal effects in several microbial species, but our mechanistic understanding of PNA activity and their target gene spectrum is limited. Here, we present a systematic analysis of PNAs targeting 11 essential genes with varying expression levels in uropathogenic Escherichia coli (UPEC). We demonstrate that UPEC is susceptible to killing by peptide-conjugated PNAs, especially when targeting the widely-used essential gene acpP. Our evaluation yields three additional promising target mRNAs for effective growth inhibition, i.e.dnaB, ftsZ and rpsH. The analysis also shows that transcript abundance does not predict target vulnerability and that PNA-mediated growth inhibition is not universally associated with target mRNA depletion. Global transcriptomic analyses further reveal PNA sequence-dependent but also -independent responses, including the induction of envelope stress response pathways. Importantly, we show that 9mer PNAs are generally as effective in inhibiting bacterial growth as their 10mer counterparts. Overall, our systematic comparison of a range of PNAs targeting mRNAs of different essential genes in UPEC suggests important features for PNA design, reveals a general bacterial response to PNA conjugates and establishes the feasibility of using PNA antibacterials to combat UPEC.
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Affiliation(s)
- Linda Popella
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, D-97080, Würzburg, Germany
| | - Jakob Jung
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, D-97080, Würzburg, Germany
| | - Phuong Thao Do
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080, Würzburg, Germany
| | - Regan J Hayward
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080, Würzburg, Germany
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080, Würzburg, Germany
- Faculty of Medicine, University of Würzburg, D-97080, Würzburg, Germany
| | - Jörg Vogel
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, D-97080, Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), D-97080, Würzburg, Germany
- Faculty of Medicine, University of Würzburg, D-97080, Würzburg, Germany
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11
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Łapińska U, Voliotis M, Lee KK, Campey A, Stone MRL, Tuck B, Phetsang W, Zhang B, Tsaneva-Atanasova K, Blaskovich MAT, Pagliara S. Fast bacterial growth reduces antibiotic accumulation and efficacy. eLife 2022; 11:e74062. [PMID: 35670099 PMCID: PMC9173744 DOI: 10.7554/elife.74062] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 05/08/2022] [Indexed: 12/11/2022] Open
Abstract
Phenotypic variations between individual microbial cells play a key role in the resistance of microbial pathogens to pharmacotherapies. Nevertheless, little is known about cell individuality in antibiotic accumulation. Here, we hypothesise that phenotypic diversification can be driven by fundamental cell-to-cell differences in drug transport rates. To test this hypothesis, we employed microfluidics-based single-cell microscopy, libraries of fluorescent antibiotic probes and mathematical modelling. This approach allowed us to rapidly identify phenotypic variants that avoid antibiotic accumulation within populations of Escherichia coli, Pseudomonas aeruginosa, Burkholderia cenocepacia, and Staphylococcus aureus. Crucially, we found that fast growing phenotypic variants avoid macrolide accumulation and survive treatment without genetic mutations. These findings are in contrast with the current consensus that cellular dormancy and slow metabolism underlie bacterial survival to antibiotics. Our results also show that fast growing variants display significantly higher expression of ribosomal promoters before drug treatment compared to slow growing variants. Drug-free active ribosomes facilitate essential cellular processes in these fast-growing variants, including efflux that can reduce macrolide accumulation. We used this new knowledge to eradicate variants that displayed low antibiotic accumulation through the chemical manipulation of their outer membrane inspiring new avenues to overcome current antibiotic treatment failures.
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Affiliation(s)
- Urszula Łapińska
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Biosciences, University of ExeterExeterUnited Kingdom
| | - Margaritis Voliotis
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Department of Mathematics, University of ExeterExeterUnited Kingdom
| | - Ka Kiu Lee
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Biosciences, University of ExeterExeterUnited Kingdom
| | - Adrian Campey
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Biosciences, University of ExeterExeterUnited Kingdom
| | - M Rhia L Stone
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of QueenslandBrisbaneAustralia
- Department of Chemistry and Chemical Biology, Rutgers, the State University of New JerseyPiscatawayUnited States
| | - Brandon Tuck
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Biosciences, University of ExeterExeterUnited Kingdom
| | - Wanida Phetsang
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of QueenslandBrisbaneAustralia
| | - Bing Zhang
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of QueenslandBrisbaneAustralia
| | - Krasimira Tsaneva-Atanasova
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Department of Mathematics, University of ExeterExeterUnited Kingdom
- EPSRC Hub for Quantitative Modelling in Healthcare, University of ExeterExeterUnited Kingdom
- Department of Bioinformatics and Mathematical Modelling, Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of SciencesSofiaBulgaria
| | - Mark AT Blaskovich
- Centre for Superbug Solutions, Institute for Molecular Bioscience, The University of QueenslandBrisbaneAustralia
| | - Stefano Pagliara
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Biosciences, University of ExeterExeterUnited Kingdom
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12
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Glover G, Voliotis M, Łapińska U, Invergo BM, Soanes D, O'Neill P, Moore K, Nikolic N, Petrov PG, Milner DS, Roy S, Heesom K, Richards TA, Tsaneva-Atanasova K, Pagliara S. Nutrient and salt depletion synergistically boosts glucose metabolism in individual Escherichia coli cells. Commun Biol 2022; 5:385. [PMID: 35444215 PMCID: PMC9021252 DOI: 10.1038/s42003-022-03336-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/30/2022] [Indexed: 12/16/2022] Open
Abstract
The interaction between a cell and its environment shapes fundamental intracellular processes such as cellular metabolism. In most cases growth rate is treated as a proximal metric for understanding the cellular metabolic status. However, changes in growth rate might not reflect metabolic variations in individuals responding to environmental fluctuations. Here we use single-cell microfluidics-microscopy combined with transcriptomics, proteomics and mathematical modelling to quantify the accumulation of glucose within Escherichia coli cells. In contrast to the current consensus, we reveal that environmental conditions which are comparatively unfavourable for growth, where both nutrients and salinity are depleted, increase glucose accumulation rates in individual bacteria and population subsets. We find that these changes in metabolic function are underpinned by variations at the translational and posttranslational level but not at the transcriptional level and are not dictated by changes in cell size. The metabolic response-characteristics identified greatly advance our fundamental understanding of the interactions between bacteria and their environment and have important ramifications when investigating cellular processes where salinity plays an important role.
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Affiliation(s)
- Georgina Glover
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - Margaritis Voliotis
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Department of Mathematics, University of Exeter, Stocker Road, Exeter, UK
| | - Urszula Łapińska
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Brandon M Invergo
- Translational Research Exchange at Exeter, University of Exeter, Exeter, UK
| | - Darren Soanes
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Paul O'Neill
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Karen Moore
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Nela Nikolic
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Institute of Science and Technology Austria, 3400, Klosterneuburg, Austria
| | - Peter G Petrov
- Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
| | - David S Milner
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Sumita Roy
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK
| | - Kate Heesom
- University of Bristol Proteomics Facility, University Walk, Bristol, BS8 1TD, UK
| | - Thomas A Richards
- Department of Zoology, University of Oxford, 11a Mansfield Road, Oxford, OX1 3SZ, UK
| | - Krasimira Tsaneva-Atanasova
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Department of Mathematics, University of Exeter, Stocker Road, Exeter, UK
- Department of Bioinformatics and Mathematical Modelling, Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, 105 Acad. G. Bonchev Str., 1113, Sofia, Bulgaria
| | - Stefano Pagliara
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
- Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4Q, UK.
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13
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Bodrenko IV, Milenkovic S, Ceccarelli M. Diffusion of molecules through nanopores under confinement: Time-scale bridging and crowding effects via Markov state model. Biomol Concepts 2022; 13:207-219. [PMID: 35417112 DOI: 10.1515/bmc-2022-0019] [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: 01/31/2022] [Accepted: 03/14/2022] [Indexed: 11/15/2022] Open
Abstract
Passive transport of molecules through nanopores is characterized by the interaction of molecules with pore internal walls and by a general crowding effect due to the constricted size of the nanopore itself, which limits the presence of molecules in its interior. The molecule-pore interaction is treated within the diffusion approximation by introducing the potential of mean force and the local diffusion coefficient for a correct statistical description. The crowding effect can be handled within the Markov state model approximation. By combining the two methods, one can deal with complex free energy surfaces taking into account crowding effects. We recapitulate the equations bridging the two models to calculate passive currents assuming a limited occupancy of the nanopore in a wide range of molecular concentrations. Several simple models are analyzed to clarify the consequences of the model. Eventually, a biologically relevant case of transport of an antibiotic molecule through a bacterial porin is used to draw conclusions (i) on the effects of crowding on transport of small molecules through biological channels, and (ii) to demonstrate its importance for modelling of cellular transport.
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Affiliation(s)
- Igor V Bodrenko
- CNR/IOM, Section of Cagliari, c/o Department of Physics, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato, Italy.,Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
| | - Stefan Milenkovic
- CNR/IOM, Section of Cagliari, c/o Department of Physics, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato, Italy
| | - Matteo Ceccarelli
- CNR/IOM, Section of Cagliari, c/o Department of Physics, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato, Italy.,Department of Physics, University of Cagliari, S.P. Monserrato-Sestu km 0.700, 09042 Monserrato, Italy
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14
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Silicon Nitride-Based Micro-Apertures Coated with Parylene for the Investigation of Pore Proteins Fused in Free-Standing Lipid Bilayers. MEMBRANES 2022; 12:membranes12030309. [PMID: 35323784 PMCID: PMC8954132 DOI: 10.3390/membranes12030309] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/25/2022] [Accepted: 03/07/2022] [Indexed: 12/21/2022]
Abstract
In this work, we present a microsystem setup for performing sensitive biological membrane translocation measurements. Thin free-standing synthetic bilayer lipid membranes (BLM) were constructed in microfabricated silicon nitride apertures (<100 µm in diameter), conformal coated with Parylene (Parylene-C or Parylene-AF4). Within these BLMs, electrophysiological measurements were conducted to monitor the behavior of different pore proteins. Two approaches to integrate pore-forming proteins into the membrane were applied: direct reconstitution and reconstitution via outer membrane vesicles (OMVs) released from Gram-negative bacteria. The advantage of utilizing OMVs is that the pore proteins remain in their native lipid and lipopolysaccharide (LPS) environment, representing a more natural state compared to the usage of fused purified pore proteins. Multiple aperture chips can be easily assembled in the 3d-printed holder to conduct parallel membrane transport investigations. Moreover, well defined microfabricated apertures are achievable with very high reproducibility. The presented microsystem allows the investigation of fast gating events (down to 1 ms), pore blocking by an antibiotic, and gating events of small pores (amplitude of approx. 3 pA).
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15
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Richter R, Kamal MAM, Koch M, Niebuur B, Huber A, Goes A, Volz C, Vergalli J, Kraus T, Müller R, Schneider‐Daum N, Fuhrmann G, Pagès J, Lehr C. An Outer Membrane Vesicle-Based Permeation Assay (OMPA) for Assessing Bacterial Bioavailability. Adv Healthc Mater 2022; 11:e2101180. [PMID: 34614289 DOI: 10.1002/adhm.202101180] [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: 06/15/2021] [Revised: 09/14/2021] [Indexed: 11/11/2022]
Abstract
When searching for new antibiotics against Gram-negative bacterial infections, a better understanding of the permeability across the cell envelope and tools to discriminate high from low bacterial bioavailability compounds are urgently needed. Inspired by the phospholipid vesicle-based permeation assay (PVPA), which is designed to predict non-facilitated permeation across phospholipid membranes, outer membrane vesicles (OMVs) of Escherichia coli either enriched or deficient of porins are employed to coat filter supports for predicting drug uptake across the complex cell envelope. OMVs and the obtained in vitro model are structurally and functionally characterized using cryo-TEM, SEM, CLSM, SAXS, and light scattering techniques. In vitro permeability, obtained from the membrane model for a set of nine antibiotics, correlates with reported in bacterio accumulation data and allows to discriminate high from low accumulating antibiotics. In contrast, the correlation of the same data set generated by liposome-based comparator membranes is poor. This better correlation of the OMV-derived membranes points to the importance of hydrophilic membrane components, such as lipopolysaccharides and porins, since those features are lacking in liposomal comparator membranes. This approach can offer in the future a high throughput screening tool with high predictive capacity or can help to identify compound- and bacteria-specific passive uptake pathways.
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Affiliation(s)
- Robert Richter
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
| | - Mohamed A. M. Kamal
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Saarland University Department of Pharmacy Campus E8.1 Saarbrücken 66123 Germany
| | - Marcus Koch
- INM – Leibniz Institute for New Materials Campus D2.2 Saarbrücken 66123 Germany
| | - Bart‐Jan Niebuur
- INM – Leibniz Institute for New Materials Campus D2.2 Saarbrücken 66123 Germany
| | - Anna‐Lena Huber
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Saarland University Department of Pharmacy Campus E8.1 Saarbrücken 66123 Germany
| | - Adriely Goes
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Saarland University Department of Pharmacy Campus E8.1 Saarbrücken 66123 Germany
| | - Carsten Volz
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
| | - Julia Vergalli
- UMR_MD1 U‐1261 Aix‐Marseille Université INSERM IRBA MCT Faculté de Pharmacie 27 Boulevard Jean Moulin Marseille 13005 France
| | - Tobias Kraus
- INM – Leibniz Institute for New Materials Campus D2.2 Saarbrücken 66123 Germany
- Colloid and Interface Chemistry Saarland University Campus D2.2 Saarbrücken 66123 Germany
| | - Rolf Müller
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Saarland University Department of Pharmacy Campus E8.1 Saarbrücken 66123 Germany
| | - Nicole Schneider‐Daum
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
| | - Gregor Fuhrmann
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Saarland University Department of Pharmacy Campus E8.1 Saarbrücken 66123 Germany
| | - Jean‐Marie Pagès
- UMR_MD1 U‐1261 Aix‐Marseille Université INSERM IRBA MCT Faculté de Pharmacie 27 Boulevard Jean Moulin Marseille 13005 France
| | - Claus‐Michael Lehr
- Helmholtz Centre for Infection Research Helmholtz Institute for Pharmaceutical Research Saarland Campus E8.1 Saarbrücken 66123 Germany
- Saarland University Department of Pharmacy Campus E8.1 Saarbrücken 66123 Germany
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16
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Exploring the permeation of fluoroquinolone metalloantibiotics across outer membrane porins by combining molecular dynamics simulations and a porin-mimetic in vitro model. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:183838. [PMID: 34896074 DOI: 10.1016/j.bbamem.2021.183838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/24/2022]
Abstract
The misuse and overuse of fluoroquinolones in recent years have triggered alarming levels of resistance to these antibiotics. Porin channels are crucial for the permeation of fluoroquinolones across the outer membrane of Gram-negative bacteria and modifications in porin expression are an important mechanism of bacterial resistance. One possible strategy to overcome this problem is the development of ternary copper complexes with fluoroquinolones. Compared to fluoroquinolones, these metalloantibiotics present a larger partition to the lipid bilayer and a more favorable permeation, by passive diffusion, across bacteriomimetic phospholipid-based model membranes. To rule out the porin-dependent pathway for the metalloantibiotics, we explored the permeation through OmpF (one of the most abundant porins present in the outer membrane of Gram-negative bacteria) using a multi-component approach. X-ray studies of OmpF porin crystals soaked with a ciprofloxacin ternary copper complex did not show a well-defined binding site for the compound. Molecular dynamics simulations showed that the translocation of the metalloantibiotic through this porin is less favorable than that of free fluoroquinolone, as it presented a much larger free energy barrier to cross the narrow constriction region of the pore. Lastly, permeability studies of different fluoroquinolones and their respective copper complexes using a porin-mimetic in vitro model corroborated the lower rate of permeation for the metalloantibiotics relative to the free antibiotics. Our results support a porin-independent mechanism for the influx of the metalloantibiotics into the bacterial cell. This finding brings additional support to the potential application of these metalloantibiotics in the fight against resistant infections and as an alternative to fluoroquinolones.
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17
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Haloi N, Vasan AK, Geddes EJ, Prasanna A, Wen PC, Metcalf WW, Hergenrother PJ, Tajkhorshid E. Rationalizing the generation of broad spectrum antibiotics with the addition of a positive charge. Chem Sci 2021; 12:15028-15044. [PMID: 34909143 PMCID: PMC8612397 DOI: 10.1039/d1sc04445a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/13/2021] [Indexed: 11/28/2022] Open
Abstract
Antibiotic resistance of Gram-negative bacteria is largely attributed to the low permeability of their outer membrane (OM). Recently, we disclosed the eNTRy rules, a key lesson of which is that the introduction of a primary amine enhances OM permeation in certain contexts. To understand the molecular basis for this finding, we perform an extensive set of molecular dynamics (MD) simulations and free energy calculations comparing the permeation of aminated and amine-free antibiotic derivatives through the most abundant OM porin of E. coli, OmpF. To improve sampling of conformationally flexible drugs in MD simulations, we developed a novel, Monte Carlo and graph theory based algorithm to probe more efficiently the rotational and translational degrees of freedom visited during the permeation of the antibiotic molecule through OmpF. The resulting pathways were then used for free-energy calculations, revealing a lower barrier against the permeation of the aminated compound, substantiating its greater OM permeability. Further analysis revealed that the amine facilitates permeation by enabling the antibiotic to align its dipole to the luminal electric field of the porin and form favorable electrostatic interactions with specific, highly-conserved charged residues. The importance of these interactions in permeation was further validated with experimental mutagenesis and whole cell accumulation assays. Overall, this study provides insights on the importance of the primary amine for antibiotic permeation into Gram-negative pathogens that could help the design of future antibiotics. We also offer a new computational approach for calculating free-energy of processes where relevant molecular conformations cannot be efficiently captured.
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Affiliation(s)
- Nandan Haloi
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Archit Kumar Vasan
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Emily J Geddes
- Department of Chemistry, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Arjun Prasanna
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
- Department of Microbiology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Po-Chao Wen
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - William W Metcalf
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
- Department of Microbiology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Paul J Hergenrother
- Department of Chemistry, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign Urbana IL 61801 USA
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18
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Miron A, Mukamel D, Posch HA. Attraction and condensation of driven tracers in a narrow channel. Phys Rev E 2021; 104:024123. [PMID: 34525576 DOI: 10.1103/physreve.104.024123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 07/28/2021] [Indexed: 11/07/2022]
Abstract
Emergent bath-mediated attraction and condensation arise when multiple particles are simultaneously driven through an equilibrated bath under geometric constraints. While such scenarios are observed in a variety of nonequilibrium phenomena with an abundance of experimental and numerical evidence, little quantitative understanding of how these interactions arise is currently available. Here we approach the problem by studying the behavior of two driven "tracer" particles, propagating through a bath in a 1D lattice with excluded-volume interactions. We apply the mean-field approximation to analytically explore the mechanism responsible for the tracers' emergent interactions and compute the resulting effective attractive potential. This mechanism is then numerically shown to extend to a realistic model of hard driven Brownian disks confined to a narrow 2D channel.
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Affiliation(s)
- Asaf Miron
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - David Mukamel
- Department of Physics of Complex Systems, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Harald A Posch
- Computational Physics Group, Faculty of Physics, University of Vienna, Vienna 1090, Austria
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19
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Chen F, Wang C, Yue L, Zhu L, Tang J, Yu X, Cao X, Schröder P, Wang Z. Cell Walls Are Remodeled to Alleviate nY 2O 3 Cytotoxicity by Elaborate Regulation of de Novo Synthesis and Vesicular Transport. ACS NANO 2021; 15:13166-13177. [PMID: 34339172 DOI: 10.1021/acsnano.1c02715] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Yttrium oxide nanoparticles (nY2O3), one of the broadly used rare earth nanoparticles, can interact with plants and possibly cause plant health and environmental impacts, but the plant defense response particularly at the nanoparticle-cell interface is largely unknown. To elucidate this, Bright Yellow 2 (BY-2) tobacco (Nicotiana tabacum L.) suspension-cultured cells were exposed to 50 mg L-1 nY2O3 (30 nm) for 12 h. Although 42.2% of the nY2O3 remained outside of protoplasts, nY2O3 could still traverse the cell wall and was partially deposited inside the vacuole. In addition to growth inhibition, morphological and compositional changes in cell walls occurred. Together with a locally thickened (7-13-fold) cell wall, increased content (up to 58%) of pectin and reduction in (up to 29%) hemicellulose were observed. Transcriptome analysis revealed that genes involved in cell wall metabolism and remodeling were highly regulated in response to nY2O3 stress. Expression of genes for pectin synthesis and degradation was up- and down-regulated by 31-78% and 13-42%, respectively, and genes for xyloglucan and pectin modifications were up- and down-regulated by 82% and 81-92%, respectively. Interestingly, vesicle trafficking seemed to be activated, enabling the repair and defense against nY2O3 disturbance. Our findings indicate that, although nY2O3 generated toxicity on BY-2 cells, it is very likely that during the recovery process cell wall remodeling was initiated to gain resistance to nY2O3 stress, demonstrating the plant's cellular regulatory machinery regarding repair and adaptation to nanoparticles like nY2O3.
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Affiliation(s)
- Feiran Chen
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Chuanxi Wang
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Le Yue
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Liqi Zhu
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Junfeng Tang
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Xiaoyu Yu
- College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Xuesong Cao
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
| | - Peter Schröder
- Research Unit Comparative Microbiome Analysis, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Zhenyu Wang
- Institute of Environmental Processes and Pollution Control, and School of Environmental and Civil Engineering, Jiangnan University, Wuxi 214122, China
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20
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Ohnishi S, Kamiya K. Formation of Giant Lipid Vesicle Containing Dual Functions Facilitates Outer Membrane Phospholipase. ACS Synth Biol 2021; 10:1837-1846. [PMID: 34258991 DOI: 10.1021/acssynbio.0c00468] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Giant lipid vesicles are used to study artificial cell models, as well as the encapsulation of biomolecules, and the reconstitution of membrane proteins on these vesicles. Recently, complex reactions in giant vesicles have been controlled by reconstituting numerous kinds of biomolecules. However, it is challenging to generate giant lipid vesicles containing a diverse set of proteins at concentrations sufficient to ensure proper functioning. Here, we describe an artificial cell model showing dual functions of small molecule transportation and small vesicle budding, using a dual functional membrane protein (transportation and phosphatase activity) called the outer membrane phospholipase (OmpLA). To the best of our knowledge, we have revealed for the first time the transportation of ions or small molecules through OmpLA on the charged lipid bilayer. The lipid composition controlled the orientation of OmpLA through proteinase K digestion. Finally, OmpLA enzyme activity of phospholipid hydrolysis caused the budding of small vesicles.
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Affiliation(s)
- Seren Ohnishi
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
| | - Koki Kamiya
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan
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21
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Yao X, Song NN, Wang J, Zhao X, Cheng MY, Zuo J, Qiu K. Influence of Electrolyte Concentration on Single-Molecule Sensing of Perfluorocarboxylic Acids. Front Chem 2021; 9:732378. [PMID: 34414165 PMCID: PMC8369427 DOI: 10.3389/fchem.2021.732378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Perfluorocarboxylic acids (PFCAs) are an emerging class of persistent organic pollutants. During the fabrication process, it is unavoidable to form PFCA homologs or isomers which exhibit distinct occurrence, bioaccumulation, and toxicity. The precision measurement of PFCAs is therefore of significant importance. However, the existing characterization techniques, such as LC-MS/MS, cannot fully meet the requirement of isomer-specific analysis, largely due to the lack of authentic standards. Single-molecule sensors (SMSs) based on nanopore electrochemistry may be a feasible solution for PFCAs determination, thanks to their ultra-high spatiotemporal resolutions. Hence, as a first step, this work was to elucidate the influence of electrolyte concentration on the four most critical indicators of nanopore measurements, and furthermore, performance of nanopore SMSs. More specifically, three of the most representative short-chain PFCAs, perfluoropentanoic acid (PFPeA), perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA), were adopted as the target analytes, aerolysin nanopore was employed as the sensing interface, and 2, 3 and 4 M KCl solutions were used as electrolytes. It was found that, when the concentration of KCl solution increased from 2 to 4 M, the conductance of aerolysin nanopore increased almost linearly at a rate of 0.5 nS per molar KCl within the whole voltage range, the current blockade of PFPeA at -50 mV increased from 61.74 to 66.57% owing to the enhanced steric exclusion effect, the maximum dwell time was more than doubled from 14.5 to 31.5 ms, and the barrier limited capture rate increased by 8.3 times from 0.46 to 3.85 Hz. As a result, when using 4 M KCl as the electrolyte, over 90% of the PFPeA, PFHxA and PFHpA were accurately identified from a mixed sample, and the calculated limit of detection of PFPeA reached 320 nM, more than 24 times lower than in 2 M KCl. It was thus clear that tuning the electrolyte concentration was a simple but very effective approach to improve the performance of nanopore SMSs for PFCAs determination.
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Affiliation(s)
- Xinyun Yao
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai, China
- School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, China
| | - Ning-Ning Song
- Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Jia Wang
- Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Xian Zhao
- Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Meng-Yuan Cheng
- Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Jiaqi Zuo
- Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
| | - Kaipei Qiu
- State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process, Shanghai, China
- Shanghai Environmental Protection Key Laboratory for Environmental Standard and Risk Management of Chemical Pollutants, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, China
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22
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Hoogenboom BW, Hough LE, Lemke EA, Lim RYH, Onck PR, Zilman A. Physics of the Nuclear Pore Complex: Theory, Modeling and Experiment. PHYSICS REPORTS 2021; 921:1-53. [PMID: 35892075 PMCID: PMC9306291 DOI: 10.1016/j.physrep.2021.03.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The hallmark of eukaryotic cells is the nucleus that contains the genome, enclosed by a physical barrier known as the nuclear envelope (NE). On the one hand, this compartmentalization endows the eukaryotic cells with high regulatory complexity and flexibility. On the other hand, it poses a tremendous logistic and energetic problem of transporting millions of molecules per second across the nuclear envelope, to facilitate their biological function in all compartments of the cell. Therefore, eukaryotes have evolved a molecular "nanomachine" known as the Nuclear Pore Complex (NPC). Embedded in the nuclear envelope, NPCs control and regulate all the bi-directional transport between the cell nucleus and the cytoplasm. NPCs combine high molecular specificity of transport with high throughput and speed, and are highly robust with respect to molecular noise and structural perturbations. Remarkably, the functional mechanisms of NPC transport are highly conserved among eukaryotes, from yeast to humans, despite significant differences in the molecular components among various species. The NPC is the largest macromolecular complex in the cell. Yet, despite its significant complexity, it has become clear that its principles of operation can be largely understood based on fundamental physical concepts, as have emerged from a combination of experimental methods of molecular cell biology, biophysics, nanoscience and theoretical and computational modeling. Indeed, many aspects of NPC function can be recapitulated in artificial mimics with a drastically reduced complexity compared to biological pores. We review the current physical understanding of the NPC architecture and function, with the focus on the critical analysis of experimental studies in cells and artificial NPC mimics through the lens of theoretical and computational models. We also discuss the connections between the emerging concepts of NPC operation and other areas of biophysics and bionanotechnology.
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Affiliation(s)
- Bart W. Hoogenboom
- London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - Loren E. Hough
- Department of Physics and BioFrontiers Institute, University of Colorado, Boulder CO 80309, United States of America
| | - Edward A. Lemke
- Biocenter Mainz, Departments of Biology and Chemistry, Johannes Gutenberg University and Institute of Molecular Biology, 55128 Mainz, Germany
| | - Roderick Y. H. Lim
- Biozentrum and the Swiss Nanoscience Institute, University of Basel, 4056 Basel, Switzerland
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Anton Zilman
- Department of Physics and Institute for Biomedical Engineering (IBME), University of Toronto, Toronto, ON M5S 1A7, Canada
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23
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Luchian T, Mereuta L, Park Y, Asandei A, Schiopu I. Single-molecule, hybridization-based strategies for short nucleic acids detection and recognition with nanopores. Proteomics 2021; 22:e2100046. [PMID: 34275186 DOI: 10.1002/pmic.202100046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/21/2021] [Accepted: 07/13/2021] [Indexed: 12/23/2022]
Abstract
DNA nanotechnology has seen large developments over the last 30 years through the combination of detection and discovery of DNAs, and solid phase synthesis to increase the chemical functionalities on nucleic acids, leading to the emergence of novel and sophisticated in features, nucleic acids-based biopolymers. Arguably, nanopores developed for fast and direct detection of a large variety of molecules, are part of a revolutionary technological evolution which led to cheaper, smaller and considerably easier to use devices enabling DNA detection and sequencing at the single-molecule level. Through their versatility, the nanopore-based tools proved useful biomedicine, nanoscale chemistry, biology and physics, as well as other disciplines spanning materials science to ecology and anthropology. This mini-review discusses the progress of nanopore- and hybridization-based DNA detection, and explores a range of state-of-the-art applications afforded through the combination of certain synthetically-derived polymers mimicking nucleic acids and nanopores, for the single-molecule biophysics on short DNA structures.
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Affiliation(s)
- Tudor Luchian
- Department of Physics, Alexandru I. Cuza University, Iasi, Romania
| | - Loredana Mereuta
- Department of Physics, Alexandru I. Cuza University, Iasi, Romania
| | - Yoonkyung Park
- Department of Biomedical Science and Research Center for Proteinaceous Materials (RCPM), Chosun University, Gwangju, Republic of Korea
| | - Alina Asandei
- Interdisciplinary Research Institute, Sciences Department, "Alexandru I. Cuza" University, Iasi, Romania
| | - Irina Schiopu
- Interdisciplinary Research Institute, Sciences Department, "Alexandru I. Cuza" University, Iasi, Romania
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24
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Xie J, Mu R, Fang M, Cheng Y, Senchyna F, Moreno A, Banaei N, Rao J. A dual-caged resorufin probe for rapid screening of infections resistant to lactam antibiotics. Chem Sci 2021; 12:9153-9161. [PMID: 34276945 PMCID: PMC8261730 DOI: 10.1039/d1sc01471d] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 05/19/2021] [Indexed: 12/04/2022] Open
Abstract
The alarming increase of antimicrobial resistance urges rapid diagnosis and pathogen specific infection management. This work reports a rapid screening assay for pathogenic bacteria resistant to lactam antibiotics. We designed a fluorogenic N-cephalosporin caged 3,7-diesterphenoxazine probe CDA that requires sequential activations to become fluorescent resorufin. A series of studies with recombinant β-lactamases and clinically prevalent pathogens including Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Serratia marcescens demonstrated that CDA possessed superior sensitivity in reporting the activity of β-lactamases including cephalosporinases and carbapenemases. After a simple filtration, lactam-resistant bacteria in urine samples could be detected at 103 colony-forming units per milliliter within 2 hours.
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Affiliation(s)
- Jinghang Xie
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine Stanford CA 94305 USA
| | - Ran Mu
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine Stanford CA 94305 USA
| | - Mingxi Fang
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine Stanford CA 94305 USA
| | - Yunfeng Cheng
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine Stanford CA 94305 USA
| | - Fiona Senchyna
- Department of Pathology, Stanford University School of Medicine Stanford CA 94305 USA
| | - Angel Moreno
- Department of Pathology, Stanford University School of Medicine Stanford CA 94305 USA
| | - Niaz Banaei
- Department of Pathology, Stanford University School of Medicine Stanford CA 94305 USA
- Clinical Microbiology Laboratory, Stanford University Medical Center Palo Alto CA 94304 USA
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine Stanford CA 94305 USA
| | - Jianghong Rao
- Departments of Radiology and Chemistry, Molecular Imaging Program at Stanford, Stanford University School of Medicine Stanford CA 94305 USA
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25
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Novikova OD, Naberezhnykh GA, Sergeev AA. Nanostructured Biosensors Based on Components of Bacterial Membranes. Biophysics (Nagoya-shi) 2021. [DOI: 10.1134/s0006350921040187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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26
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Richter R, Lehr CM. Extracellular vesicles as novel assay tools to study cellular interactions of anti-infective compounds - A perspective. Adv Drug Deliv Rev 2021; 173:492-503. [PMID: 33857554 DOI: 10.1016/j.addr.2021.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/21/2021] [Accepted: 04/08/2021] [Indexed: 12/13/2022]
Abstract
Sudden outbreaks of novel infectious diseases and the persistent evolution of antimicrobial resistant pathogens make it necessary to develop specific tools to quickly understand pathogen-cell interactions and to study appropriate drug delivery strategies. Extracellular vesicles (EVs) are cell-specific biogenic transport systems, which are gaining more and more popularity as either diagnostic markers or drug delivery systems. Apart from that, there are emerging possibilities for EVs as tools to study drug penetration, drug-membrane interactions as well as pathogen-membrane interactions. However, it appears that the potential of EVs for such applications has not been fully exploited yet. Considering the vast variety of cells that can be involved in an infection, vesicle-based analytical methods are just emerging and the number of reported applications is still relatively small. Aim of this review is to discuss the current state of the art of EV-based assays, especially in the context of antimicrobial research and therapy, and to present some new perspectives for a more exhaustive and creative exploration in the future.
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Affiliation(s)
- Robert Richter
- Department of Drug Delivery Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) Helmholtz-Centre for Infection Research (HZI), Campus E8.1, 66123 Saarbrücken, Germany
| | - Claus-Michael Lehr
- Department of Drug Delivery Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS) Helmholtz-Centre for Infection Research (HZI), Campus E8.1, 66123 Saarbrücken, Germany; Department of Pharmacy, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
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27
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Bartsch A, Ives CM, Kattner C, Pein F, Diehn M, Tanabe M, Munk A, Zachariae U, Steinem C, Llabrés S. An antibiotic-resistance conferring mutation in a neisserial porin: Structure, ion flux, and ampicillin binding. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2021; 1863:183601. [PMID: 33675718 PMCID: PMC8047873 DOI: 10.1016/j.bbamem.2021.183601] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/13/2021] [Accepted: 02/19/2021] [Indexed: 12/18/2022]
Abstract
Gram-negative bacteria cause the majority of highly drug-resistant bacterial infections. To cross the outer membrane of the complex Gram-negative cell envelope, antibiotics permeate through porins, trimeric channel proteins that enable the exchange of small polar molecules. Mutations in porins contribute to the development of drug-resistant phenotypes. In this work, we show that a single point mutation in the porin PorB from Neisseria meningitidis, the causative agent of bacterial meningitis, can strongly affect the binding and permeation of beta-lactam antibiotics. Using X-ray crystallography, high-resolution electrophysiology, atomistic biomolecular simulation, and liposome swelling experiments, we demonstrate differences in drug binding affinity, ion selectivity and drug permeability of PorB. Our work further reveals distinct interactions between the transversal electric field in the porin eyelet and the zwitterionic drugs, which manifest themselves under applied electric fields in electrophysiology and are altered by the mutation. These observations may apply more broadly to drug-porin interactions in other channels. Our results improve the molecular understanding of porin-based drug-resistance in Gram-negative bacteria.
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Affiliation(s)
- Annika Bartsch
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstraße 2, 37077 Göttingen, Germany
| | - Callum M Ives
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Christof Kattner
- ZIK HALOmem, Membrane Protein Biochemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes Straße 3, 06120 Halle (Saale), Germany
| | - Florian Pein
- Institute for Mathematical Stochastics, University of Göttingen, Goldschmidtstraße 7, 37077 Göttingen, Germany
| | - Manuel Diehn
- Institute for Mathematical Stochastics, University of Göttingen, Goldschmidtstraße 7, 37077 Göttingen, Germany
| | - Mikio Tanabe
- Institute of Materials Structure Science, Structural Biology Research Center, KEK/High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan
| | - Axel Munk
- Institute for Mathematical Stochastics, University of Göttingen, Goldschmidtstraße 7, 37077 Göttingen, Germany
| | - Ulrich Zachariae
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK; Physics, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 4NH, UK.
| | - Claudia Steinem
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstraße 2, 37077 Göttingen, Germany; Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany.
| | - Salomé Llabrés
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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28
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The Influence of Permeability through Bacterial Porins in Whole-Cell Compound Accumulation. Antibiotics (Basel) 2021; 10:antibiotics10060635. [PMID: 34073313 PMCID: PMC8226570 DOI: 10.3390/antibiotics10060635] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/24/2021] [Indexed: 01/09/2023] Open
Abstract
The lack of new drugs for Gram-negative pathogens is a global threat to modern medicine. The complexity of their cell envelope, with an additional outer membrane, hinders internal accumulation and thus, the access of molecules to their targets. Our limited understanding of the molecular basis for compound influx and efflux from these pathogens is a major bottleneck for the discovery of effective antibacterial compounds. Here we analyse the correlation between the whole-cell compound accumulation of ~200 molecules and their predicted porin permeability coefficient (influx), using a recently developed scoring function. We found a strong linear relationship (74%) between the two, confirming porins key in compound uptake in Gram-negative bacteria. The analysis of this unique dataset aids to better understand the molecular descriptors behind whole-cell accumulation and molecular uptake in Gram-negative bacteria.
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29
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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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30
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Rybenkov VV, Zgurskaya HI, Ganguly C, Leus IV, Zhang Z, Moniruzzaman M. The Whole Is Bigger than the Sum of Its Parts: Drug Transport in the Context of Two Membranes with Active Efflux. Chem Rev 2021; 121:5597-5631. [PMID: 33596653 PMCID: PMC8369882 DOI: 10.1021/acs.chemrev.0c01137] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell envelope plays a dual role in the life of bacteria by simultaneously protecting it from a hostile environment and facilitating access to beneficial molecules. At the heart of this ability lie the restrictive properties of the cellular membrane augmented by efflux transporters, which preclude intracellular penetration of most molecules except with the help of specialized uptake mediators. Recently, kinetic properties of the cell envelope came into focus driven on one hand by the urgent need in new antibiotics and, on the other hand, by experimental and theoretical advances in studies of transmembrane transport. A notable result from these studies is the development of a kinetic formalism that integrates the Michaelis-Menten behavior of individual transporters with transmembrane diffusion and offers a quantitative basis for the analysis of intracellular penetration of bioactive compounds. This review surveys key experimental and computational approaches to the investigation of transport by individual translocators and in whole cells, summarizes key findings from these studies and outlines implications for antibiotic discovery. Special emphasis is placed on Gram-negative bacteria, whose envelope contains two separate membranes. This feature sets these organisms apart from Gram-positive bacteria and eukaryotic cells by providing them with full benefits of the synergy between slow transmembrane diffusion and active efflux.
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Affiliation(s)
- Valentin V Rybenkov
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Chhandosee Ganguly
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Inga V Leus
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Zhen Zhang
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Mohammad Moniruzzaman
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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31
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Mastering the Gram-negative bacterial barrier - Chemical approaches to increase bacterial bioavailability of antibiotics. Adv Drug Deliv Rev 2021; 172:339-360. [PMID: 33705882 DOI: 10.1016/j.addr.2021.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/08/2021] [Accepted: 02/18/2021] [Indexed: 02/07/2023]
Abstract
To win the battle against resistant, pathogenic bacteria, novel classes of anti-infectives and targets are urgently needed. Bacterial uptake, distribution, metabolic and efflux pathways of antibiotics in Gram-negative bacteria determine what we here refer to as bacterial bioavailability. Understanding these mechanisms from a chemical perspective is essential for anti-infective activity and hence, drug discovery as well as drug delivery. A systematic and critical discussion of in bacterio, in vitro and in silico assays reveals that a sufficiently accurate holistic approach is still missing. We expect new findings based on Gram-negative bacterial bioavailability to guide future anti-infective research.
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32
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Gałczyńska K, Rachuna J, Ciepluch K, Kowalska M, Wąsik S, Kosztołowicz T, Lewandowska KD, Semaniak J, Kurdziel K, Arabski M. Experimental and Theoretical Analysis of Metal Complex Diffusion through Cell Monolayer. ENTROPY 2021; 23:e23030360. [PMID: 33802897 PMCID: PMC8002612 DOI: 10.3390/e23030360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/11/2021] [Accepted: 03/15/2021] [Indexed: 01/12/2023]
Abstract
The study of drugs diffusion through different biological membranes constitutes an essential step in the development of new pharmaceuticals. In this study, the method based on the monolayer cell culture of CHO-K1 cells has been developed in order to emulate the epithelial cells barrier in permeability studies by laser interferometry. Laser interferometry was employed for the experimental analysis of nickel(II) and cobalt(II) complexes with 1-allylimidazole or their chlorides’ diffusion through eukaryotic cell monolayers. The amount (mol) of nickel(II) and cobalt(II) chlorides transported through the monolayer was greater than that of metals complexed with 1-allylimidazole by 4.34-fold and 1.45-fold, respectively, after 60 min. Thus, laser interferometry can be used for the quantitative analysis of the transport of compounds through eukaryotic cell monolayers, and the resulting parameters can be used to formulate a mathematical description of this process.
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Affiliation(s)
- Katarzyna Gałczyńska
- Institute of Biology, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (K.G.); (J.R.); (K.C.); (M.K.)
| | - Jarosław Rachuna
- Institute of Biology, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (K.G.); (J.R.); (K.C.); (M.K.)
| | - Karol Ciepluch
- Institute of Biology, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (K.G.); (J.R.); (K.C.); (M.K.)
| | - Magdalena Kowalska
- Institute of Biology, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (K.G.); (J.R.); (K.C.); (M.K.)
| | - Sławomir Wąsik
- Institute of Physics, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (S.W.); (T.K.); (J.S.)
| | - Tadeusz Kosztołowicz
- Institute of Physics, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (S.W.); (T.K.); (J.S.)
| | - Katarzyna D. Lewandowska
- Department of Radiological Informatics and Statistics, Medical University of Gdańsk, Tuwima 15, 80-210 Gdańsk, Poland;
| | - Jacek Semaniak
- Institute of Physics, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (S.W.); (T.K.); (J.S.)
| | - Krystyna Kurdziel
- Institute of Chemistry, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland;
| | - Michał Arabski
- Institute of Biology, Jan Kochanowski University, Uniwersytecka 7, 25-406 Kielce, Poland; (K.G.); (J.R.); (K.C.); (M.K.)
- Correspondence: ; Tel./Fax: +48-41-349-63-31
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33
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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: 100] [Impact Index Per Article: 33.3] [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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34
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Gezelle J, Saggu G, Desai SA. Promises and Pitfalls of Parasite Patch-clamp. Trends Parasitol 2021; 37:414-429. [PMID: 33640269 DOI: 10.1016/j.pt.2021.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 01/31/2021] [Accepted: 02/01/2021] [Indexed: 11/25/2022]
Abstract
Protozoan parasites acquire essential ions, nutrients, and other solutes from their insect and vertebrate hosts by transmembrane uptake. For intracellular stages, these solutes must cross additional membranous barriers. At each step, ion channels and transporters mediate not only this uptake but also the removal of waste products. These transport proteins are best isolated and studied with patch-clamp, but these methods remain accessible to only a few parasitologists due to specialized instrumentation and the required training in both theory and practice. Here, we provide an overview of patch-clamp, describing the advantages and limitations of the technology and highlighting issues that may lead to incorrect conclusions. We aim to help non-experts understand and critically assess patch-clamp data in basic research studies.
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Affiliation(s)
- Jeanine Gezelle
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Gagandeep Saggu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
| | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA.
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35
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Rosencrans WM, Aguilella VM, Rostovtseva TK, Bezrukov SM. α-Synuclein emerges as a potent regulator of VDAC-facilitated calcium transport. Cell Calcium 2021; 95:102355. [PMID: 33578201 DOI: 10.1016/j.ceca.2021.102355] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 01/04/2021] [Indexed: 02/06/2023]
Abstract
Voltage-dependent anion channel (VDAC) is the most ubiquitous channel at the mitochondrial outer membrane, and is believed to be the pathway for calcium entering or leaving the mitochondria. Therefore, understanding the molecular mechanisms of how VDAC regulates calcium influx and efflux from the mitochondria is of particular interest for mitochondrial physiology. When the Parkinson's disease (PD) related neuronal protein, alpha-synuclein (αSyn), is added to the reconstituted VDAC, it reversibly and partially blocks VDAC conductance by its acidic C-terminal tail. Using single-molecule VDAC electrophysiology of reconstituted VDAC we now demonstrate that, at CaCl2 concentrations below 150 mM, αSyn reverses the channel's selectivity from anionic to cationic. Importantly, we find that the decrease in channel conductance upon its blockage by αSyn is hugely overcompensated by a favorable change in the electrostatic environment for calcium, making the blocked state orders-of-magnitude more selective for calcium and thus increasing its net flux. -Our findings with higher calcium concentrations also demonstrate that the phenomenon of "charge inversion" is taking place at the level of a single polypeptide chain. Measurements of ion selectivity of three VDAC isoforms in CaCl2 gradient show that VDAC3 exhibits the highest calcium permeability among them, followed by VDAC2 and VDAC1, thus pointing to isoform-dependent physiological function. Mutation of the E73 residue - VDAC1 purported calcium binding site - shows that there is no measurable effect of the mutation in either open or αSyn-blocked VDAC1 states. Our results confirm VDACs involvement in calcium signaling and reveal a new regulatory role of αSyn, with clear implications for both normal calcium signaling and PD-associated mitochondrial dysfunction.
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Affiliation(s)
- William M Rosencrans
- Section on Molecular Transport, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Vicente M Aguilella
- Laboratory of Molecular Biophysics, Department of Physics, Universitat Jaume I, Av. Vicent Sos Baynat s/n 12071, Castellón, Spain
| | - 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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36
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Sargun A, Johnstone TC, Zhi H, Raffatellu M, Nolan EM. Enterobactin- and salmochelin-β-lactam conjugates induce cell morphologies consistent with inhibition of penicillin-binding proteins in uropathogenic Escherichia coli CFT073. Chem Sci 2021; 12:4041-4056. [PMID: 34163675 PMCID: PMC8179508 DOI: 10.1039/d0sc04337k] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 12/31/2020] [Indexed: 12/15/2022] Open
Abstract
The design and synthesis of narrow-spectrum antibiotics that target a specific bacterial strain, species, or group of species is a promising strategy for treating bacterial infections when the causative agent is known. In this work, we report the synthesis and evaluation of four new siderophore-β-lactam conjugates where the broad-spectrum β-lactam antibiotics cephalexin (Lex) and meropenem (Mem) are covalently attached to either enterobactin (Ent) or diglucosylated Ent (DGE) via a stable polyethylene glycol (PEG3) linker. These siderophore-β-lactam conjugates showed enhanced minimum inhibitory concentrations against Escherichia coli compared to the parent antibiotics. Uptake studies with uropathogenic E. coli CFT073 demonstrated that the DGE-β-lactams target the pathogen-associated catecholate siderophore receptor IroN. A comparative analysis of siderophore-β-lactams harboring ampicillin (Amp), Lex and Mem indicated that the DGE-Mem conjugate is advantageous because it targets IroN and exhibits low minimum inhibitory concentrations, fast time-kill kinetics, and enhanced stability to serine β-lactamases. Phase-contrast and fluorescence imaging of E. coli treated with the siderophore-β-lactam conjugates revealed cellular morphologies consistent with the inhibition of penicillin-binding proteins PBP3 (Ent/DGE-Amp/Lex) and PBP2 (Ent/DGE-Mem). Overall, this work illuminates the uptake and cell-killing activity of Ent- and DGE-β-lactam conjugates against E. coli and supports that native siderophore scaffolds provide the opportunity for narrowing the activity spectrum of antibiotics in clinical use and targeting pathogenicity.
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Affiliation(s)
- Artur Sargun
- Department of Chemistry, Massachusetts Institute of Technology Cambridge MA 02139 USA +1-617-452-2495
| | - Timothy C Johnstone
- Department of Chemistry, Massachusetts Institute of Technology Cambridge MA 02139 USA +1-617-452-2495
| | - Hui Zhi
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego La Jolla CA 92093 USA
| | - Manuela Raffatellu
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California San Diego La Jolla CA 92093 USA
- Center for Microbiome Innovation, University of California San Diego La Jolla CA 92093 USA
- Chiba University-UC San Diego Center for Mucosal Immunology, Allergy, and Vaccines La Jolla CA 92093 USA
| | - Elizabeth M Nolan
- Department of Chemistry, Massachusetts Institute of Technology Cambridge MA 02139 USA +1-617-452-2495
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37
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Meyer CE, Craciun I, Schoenenberger CA, Wehr R, Palivan CG. Catalytic polymersomes to produce strong and long-lasting bioluminescence. NANOSCALE 2021; 13:66-70. [PMID: 33350424 DOI: 10.1039/d0nr07178a] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Here, we introduce an artificial bioluminescent nanocompartment based on the encapsulation of light-producing enzymes, luciferases, inside polymersomes. We exploit nanocompartmentalization to enhance luciferase stability in a cellular environment but also to positively modulate enzyme kinetics to achieve a long-lasting glow type signal. These features pave the way for expanding bioluminescence to nanotechnology-based applications.
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Affiliation(s)
- Claire Elsa Meyer
- Department of Chemistry, University of Basel, Mattenstrasse 24a, Basel-4002, Switzerland.
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38
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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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Sun J, Thakur AK, Movileanu L. Protein Ligand-Induced Amplification in the 1/ f Noise of a Protein-Selective Nanopore. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15247-15257. [PMID: 33307706 PMCID: PMC7755739 DOI: 10.1021/acs.langmuir.0c02498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Previous studies of transmembrane protein channels have employed noise analysis to examine their statistical current fluctuations. In general, these explorations determined a substrate-induced amplification in the Gaussian white noise of these systems at a low-frequency regime. This outcome implies a lack of slowly appearing fluctuations in the number and local mobility of diffusing charges in the presence of channel substrates. Such parameters are among the key factors in generating a low-frequency 1/f noise. Here, we show that a protein-selective biological nanopore exhibits a substrate-induced amplification in the 1/f noise. The modular composition of this biological nanopore includes a hydrophilic transmembrane protein pore fused to a water-soluble binding protein on its extramembranous side. In addition, this protein nanopore shows an open substate populated by a high-frequency current noise because of the flickering of an engineered polypeptide adaptor at the tip of the pore. However, the physical association of the protein ligand with the binding domain reversibly switches the protein nanopore from a high-frequency noise substate into a quiet substate. In the absence of the protein ligand, our nanopore shows a low-frequency white noise. Remarkably, in the presence of the protein ligand, an amplified low-frequency 1/f noise was detected in a ligand concentration-dependent fashion. This finding suggests slowly occurring equilibrium fluctuations in the density and local mobility of charge carriers under these conditions. Furthermore, we report that the excess in 1/f noise is generated by reversible switches between the noisy ligand-released substate and the quiet ligand-captured substate. Finally, quantitative aspects of the low-frequency 1/f noise are in accord with theoretical predictions of the current noise analysis of protein channel-ligand interactions.
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Affiliation(s)
- Jiaxin Sun
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Avinash Kumar Thakur
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
- Structural Biology, Biochemistry, and Biophysics Program, Syracuse University, 111 College Place, Syracuse, New York 13244-4100, USA
- Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, New York 13244, USA
- The corresponding author’s contact information: Liviu Movileanu, PhD, Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA. Phone: 315-443-8078; Fax: 315-443-9103;
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40
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Zhao S, Adamiak JW, Bonifay V, Mehla J, Zgurskaya HI, Tan DS. Defining new chemical space for drug penetration into Gram-negative bacteria. Nat Chem Biol 2020; 16:1293-1302. [PMID: 33199906 PMCID: PMC7897441 DOI: 10.1038/s41589-020-00674-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 09/11/2020] [Indexed: 12/24/2022]
Abstract
We live in the era of antibiotic resistance, and this problem will progressively worsen if no new solutions emerge. In particular, Gram-negative pathogens present both biological and chemical challenges that hinder the discovery of new antibacterial drugs. First, these bacteria are protected from a variety of structurally diverse drugs by a low-permeability barrier composed of two membranes with distinct permeability properties, in addition to active drug efflux, making this cell envelope impermeable to most compounds. Second, chemical libraries currently used in drug discovery contain few compounds that can penetrate Gram-negative bacteria. As a result of these challenges, intensive screening campaigns have led to few successes, highlighting the need for new approaches to identify regions of chemical space that are specifically relevant to antibacterial drug discovery. Herein we provide an overview of emerging insights into this problem and outline a general approach to addressing it using prospective analysis of chemical libraries for the ability of compounds to accumulate in Gram-negative bacteria. The overall goal is to develop robust cheminformatic tools to predict Gram-negative permeation and efflux, which can then be used to guide medicinal chemistry campaigns and the design of antibacterial discovery libraries.
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Affiliation(s)
- Shibin Zhao
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Justyna W Adamiak
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Vincent Bonifay
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Jitender Mehla
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, USA.
| | - Derek S Tan
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Tri-Institutional Research Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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41
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Richter R, Kamal M, García-Rivera MA, Kaspar J, Junk M, Elgaher WA, Srikakulam SK, Gress A, Beckmann A, Grißmer A, Meier C, Vielhaber M, Kalinina O, Hirsch AK, Hartmann RW, Brönstrup M, Schneider-Daum N, Lehr CM. A hydrogel-based in vitro assay for the fast prediction of antibiotic accumulation in Gram-negative bacteria. Mater Today Bio 2020; 8:100084. [PMID: 33313504 PMCID: PMC7720078 DOI: 10.1016/j.mtbio.2020.100084] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 11/30/2022] Open
Abstract
The pipeline of antibiotics has been for decades on an alarmingly low level. Considering the steadily emerging antibiotic resistance, novel tools are needed for early and easy identification of effective anti-infective compounds. In Gram-negative bacteria, the uptake of anti-infectives is especially limited. We here present a surprisingly simple in vitro model of the Gram-negative bacterial envelope, based on 20% (w/v) potato starch gel, printed on polycarbonate 96-well filter membranes. Rapid permeability measurements across this polysaccharide hydrogel allowed to correctly predict either high or low accumulation for all 16 tested anti-infectives in living Escherichia coli. Freeze-fracture TEM supports that the macromolecular network structure of the starch hydrogel may represent a useful surrogate of the Gram-negative bacterial envelope. A random forest analysis of in vitro data revealed molecular mass, minimum projection area, and rigidity as the most critical physicochemical parameters for hydrogel permeability, in agreement with reported structural features needed for uptake into Gram-negative bacteria. Correlating our dataset of 27 antibiotics from different structural classes to reported MIC values of nine clinically relevant pathogens allowed to distinguish active from nonactive compounds based on their low in vitro permeability specifically for Gram-negatives. The model may help to identify poorly permeable antimicrobial candidates before testing them on living bacteria.
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Affiliation(s)
- Robert Richter
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
- Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany
| | - Mohamed.A.M. Kamal
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Mariel A. García-Rivera
- Department of Chemical Biology, Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany
| | - Jerome Kaspar
- Institute of Engineering Design, Saarland University, 66123 Saarbrücken, Germany
| | - Maximilian Junk
- Institute of Engineering Design, Saarland University, 66123 Saarbrücken, Germany
| | - Walid A.M. Elgaher
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Sanjay Kumar Srikakulam
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Alexander Gress
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Anja Beckmann
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Germany
| | - Alexander Grißmer
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Germany
| | - Carola Meier
- Department of Anatomy and Cell Biology, Saarland University, 66421 Homburg, Germany
| | - Michael Vielhaber
- Institute of Engineering Design, Saarland University, 66123 Saarbrücken, Germany
| | - Olga Kalinina
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
- Medical Faculty, Saarland University, 66421 Homburg, Germany
| | - Anna K.H. Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
- Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany
| | - Rolf W. Hartmann
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research (HZI), 38124 Braunschweig, Germany
- German Centre for Infection Research (DZIF), 38124 Braunschweig, Germany
| | - Nicole Schneider-Daum
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
| | - Claus-Michael Lehr
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) – Helmholtz Centre for Infection Research (HZI), 66123 Saarbrücken, Germany
- Department of Pharmacy, Saarland University, 66123 Saarbrücken, Germany
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42
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Dai T, Xie J, Zhu Q, Kamariza M, Jiang K, Bertozzi CR, Rao J. A Fluorogenic Trehalose Probe for Tracking Phagocytosed Mycobacterium tuberculosis. J Am Chem Soc 2020; 142:15259-15264. [DOI: 10.1021/jacs.0c07700] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Tingting Dai
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jinghang Xie
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Qihua Zhu
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 211198, China
- Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211198, China
| | - Mireille Kamariza
- Department of Biology, Stanford University, Stanford, California 94305, United States
| | - Ke Jiang
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
| | - Carolyn R. Bertozzi
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Howard Hughes Medical Institute, Stanford University, Stanford, California 94305, United States
| | - Jianghong Rao
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
- Department of Radiology, Molecular Imaging Program at Stanford, Stanford University School of Medicine, Stanford, California 94305, United States
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43
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Cama J, Voliotis M, Metz J, Smith A, Iannucci J, Keyser UF, Tsaneva-Atanasova K, Pagliara S. Single-cell microfluidics facilitates the rapid quantification of antibiotic accumulation in Gram-negative bacteria. LAB ON A CHIP 2020; 20:2765-2775. [PMID: 32613221 PMCID: PMC7953842 DOI: 10.1039/d0lc00242a] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/15/2020] [Indexed: 06/01/2023]
Abstract
The double-membrane cell envelope of Gram-negative bacteria is a formidable barrier to intracellular antibiotic accumulation. A quantitative understanding of antibiotic transport in these cells is crucial for drug development, but this has proved elusive due to a dearth of suitable investigative techniques. Here we combine microfluidics and time-lapse auto-fluorescence microscopy to rapidly quantify antibiotic accumulation in hundreds of individual Escherichia coli cells. By serially manipulating the microfluidic environment, we demonstrated that stationary phase Escherichia coli, traditionally more refractory to antibiotics than growing cells, display reduced accumulation of the antibiotic ofloxacin compared to actively growing cells. Our novel microfluidic method facilitates the quantitative comparison of the role of the microenvironment versus that of the absence of key membrane transport pathways in cellular drug accumulation. Unlike traditional techniques, our assay is rapid, studying accumulation as the cells are dosed with the drug. This platform provides a powerful new tool for studying antibiotic accumulation in bacteria, which will be critical for the rational development of the next generation of antibiotics.
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Affiliation(s)
- Jehangir Cama
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- College of Engineering
, Mathematics and Physical Sciences
, University of Exeter
,
Exeter EX4 4QF
, UK
- Cavendish Laboratory
, Department of Physics
, University of Cambridge
,
JJ Thomson Avenue
, Cambridge CB3 0HE
, UK
| | - Margaritis Voliotis
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- College of Engineering
, Mathematics and Physical Sciences
, University of Exeter
,
Exeter EX4 4QF
, UK
| | - Jeremy Metz
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- School of Biosciences
, College of Life and Environmental Sciences
, University of Exeter
,
Exeter EX4 4QD
, UK
.
| | - Ashley Smith
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- School of Biosciences
, College of Life and Environmental Sciences
, University of Exeter
,
Exeter EX4 4QD
, UK
.
| | - Jari Iannucci
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- School of Biosciences
, College of Life and Environmental Sciences
, University of Exeter
,
Exeter EX4 4QD
, UK
.
| | - Ulrich F. Keyser
- Cavendish Laboratory
, Department of Physics
, University of Cambridge
,
JJ Thomson Avenue
, Cambridge CB3 0HE
, UK
| | - Krasimira Tsaneva-Atanasova
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- College of Engineering
, Mathematics and Physical Sciences
, University of Exeter
,
Exeter EX4 4QF
, UK
| | - Stefano Pagliara
- Living Systems Institute
, University of Exeter
,
Exeter EX4 4QD
, UK
.
- School of Biosciences
, College of Life and Environmental Sciences
, University of Exeter
,
Exeter EX4 4QD
, UK
.
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44
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Bel G, Zilman A, Kolomeisky AB. Different time scales in dynamic systems with multiple outcomes. J Chem Phys 2020; 153:054107. [PMID: 32770919 DOI: 10.1063/5.0018558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stochastic biochemical and transport processes have various final outcomes, and they can be viewed as dynamic systems with multiple exits. Many current theoretical studies, however, typically consider only a single time scale for each specific outcome, effectively corresponding to a single-exit process and assuming the independence of each exit process. However, the presence of other exits influences the statistical properties and dynamics measured at any specific exit. Here, we present theoretical arguments to explicitly show the existence of different time scales, such as mean exit times and inverse exit fluxes, for dynamic processes with multiple exits. This implies that the statistics of any specific exit dynamics cannot be considered without taking into account the presence of other exits. Several illustrative examples are described in detail using analytical calculations, mean-field estimates, and kinetic Monte Carlo computer simulations. The underlying microscopic mechanisms for the existence of different time scales are discussed. The results are relevant for understanding the mechanisms of various biological, chemical, and industrial processes, including transport through channels and pores.
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Affiliation(s)
- G Bel
- Department of Solar Energy and Environmental Physics, BIDR, and Department of Physics, Ben-Gurion University of the Negev, Sede Boqer Campus 8499000, Israel
| | - A Zilman
- Department of Physics and Institute for Biomaterials and Bioengineering, University of Toronto, 60 Saint George St., Toronto, Ontario M5S 1A7, Canada
| | - A B Kolomeisky
- Department of Chemistry and Center for Theoretical Biological Physics, Department of Chemical and Biomolecular Engineering, Department of Physics and Astronomy, Rice University, Houston, Texas 77005-1892, USA
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45
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Biedermann F, Ghale G, Hennig A, Nau WM. Fluorescent artificial receptor-based membrane assay (FARMA) for spatiotemporally resolved monitoring of biomembrane permeability. Commun Biol 2020; 3:383. [PMID: 32669621 PMCID: PMC7363885 DOI: 10.1038/s42003-020-1108-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 06/19/2020] [Indexed: 02/07/2023] Open
Abstract
The spatiotemporally resolved monitoring of membrane translocation, e.g., of drugs or toxins, has been a long-standing goal. Herein, we introduce the fluorescent artificial receptor-based membrane assay (FARMA), a facile, label-free method. With FARMA, the permeation of more than hundred organic compounds (drugs, toxins, pesticides, neurotransmitters, peptides, etc.) through vesicular phospholipid bilayer membranes has been monitored in real time (µs-h time scale) and with high sensitivity (nM-µM concentration), affording permeability coefficients across an exceptionally large range from 10-9-10-3 cm s-1. From a fundamental point of view, FARMA constitutes a powerful tool to assess structure-permeability relationships and to test biophysical models for membrane passage. From an applied perspective, FARMA can be extended to high-throughput screening by adaption of the microplate reader format, to spatial monitoring of membrane permeation by microscopy imaging, and to the compartmentalized monitoring of enzymatic activity.
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Affiliation(s)
- Frank Biedermann
- Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany.
| | - Garima Ghale
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Andreas Hennig
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Werner M Nau
- Department of Life Sciences and Chemistry, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany.
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46
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Wang J, Terrasse R, Bafna JA, Benier L, Winterhalter M. Elektrophysiologische Charakterisierung des Transports von Antibiotika durch äußere Membrankanäle in Gram‐negativen Bakterien in Gegenwart von Lipopolysacchariden. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201913618] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Jiajun Wang
- Department of Life Sciences and Chemistry Jacobs University Bremen 28759 Bremen Deutschland
- Current address: School of Chemistry and Molecular Engineering East China University of Science and Technology 200237 Shanghai China
- School of Chemistry and Chemical Engineering Nanjing University 210023 Nanjing China
| | - Rémi Terrasse
- Department of Life Sciences and Chemistry Jacobs University Bremen 28759 Bremen Deutschland
| | - Jayesh Arun Bafna
- Department of Life Sciences and Chemistry Jacobs University Bremen 28759 Bremen Deutschland
| | - Lorraine Benier
- Department of Life Sciences and Chemistry Jacobs University Bremen 28759 Bremen Deutschland
| | - Mathias Winterhalter
- Department of Life Sciences and Chemistry Jacobs University Bremen 28759 Bremen Deutschland
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47
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Wang J, Terrasse R, Bafna JA, Benier L, Winterhalter M. Electrophysiological Characterization of Transport Across Outer-Membrane Channels from Gram-Negative Bacteria in Presence of Lipopolysaccharides. Angew Chem Int Ed Engl 2020; 59:8517-8521. [PMID: 32023354 PMCID: PMC7317717 DOI: 10.1002/anie.201913618] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/26/2019] [Indexed: 02/05/2023]
Abstract
Multi-drug resistance in Gram-negative bacteria is often associated with low permeability of the outer membrane. To investigate the role of membrane channels in the uptake of antibiotics, we present an approach using fusion of native outer membrane vesicles (OMVs) into a planar lipid bilayer, allowing characterization of membrane protein channels in their native environment. Two major membrane channels from E. coli, OmpF and OmpC, were overexpressed from the host and the corresponding OMVs were collected. Each OMV fusion surprisingly revealed only single or few channel activities. The asymmetry of the OMVs translates after fusion into the lipid membrane with the lipopolysaccharides (LPS) dominantly present at the side of OMV addition. Compared to the conventional reconstitution method, the channels fused from OMVs containing LPS have similar conductance but a much broader distribution and significantly lower permeation. We suggest using outer membrane vesicles for functional and structural studies of membrane channels in the native membrane.
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Affiliation(s)
- Jiajun Wang
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany.,Current address: School of Chemistry and Molecular Engineering, East China University of Science and Technology, 200237, Shanghai, China.,School of Chemistry and Chemical Engineering, Nanjing University, 210023, Nanjing, China
| | - Rémi Terrasse
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany
| | - Jayesh Arun Bafna
- Department of Life Sciences and Chemistry, Jacobs University Bremen, 28759, Bremen, Germany
| | - Lorraine Benier
- 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
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Zgurskaya HI, Rybenkov VV. Permeability barriers of Gram-negative pathogens. Ann N Y Acad Sci 2020; 1459:5-18. [PMID: 31165502 PMCID: PMC6940542 DOI: 10.1111/nyas.14134] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/06/2019] [Accepted: 05/13/2019] [Indexed: 12/13/2022]
Abstract
Most clinical antibiotics do not have efficacy against Gram-negative pathogens, mainly because these cells are protected by the permeability barrier comprising the two membranes with active efflux. The emergence of multidrug-resistant Gram-negative strains threatens the utility even of last resort therapeutic treatments. Significant efforts at different levels of resolution are currently focused on finding a solution to this nonpermeation problem and developing new approaches to the optimization of drug activities against multidrug-resistant pathogens. The exceptional efficiency of the Gram-negative permeability barrier is the result of a complex interplay between the two opposing fluxes of drugs across the two membranes. In this review, we describe the current state of understanding of the problem and the recent advances in theoretical and empirical approaches to characterization of drug permeation and active efflux in Gram-negative bacteria.
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Affiliation(s)
- Helen I Zgurskaya
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma
| | - Valentin V Rybenkov
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma, Norman, Oklahoma
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Ferreira RJ, Kasson PM. Antibiotic Uptake Across Gram-Negative Outer Membranes: Better Predictions Towards Better Antibiotics. ACS Infect Dis 2019; 5:2096-2104. [PMID: 31593635 DOI: 10.1021/acsinfecdis.9b00201] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Crossing the Gram-negative bacterial membrane poses a major barrier to antibiotic development, as many small molecules that can biochemically inhibit key bacterial processes are rendered microbiologically ineffective by their poor cellular uptake. The outer membrane is the major permeability barrier for many drug-like molecules, and the chemical properties that enable efficient uptake into mammalian cells fail to predict bacterial uptake. We have developed a computational method for accurate prospective prediction of outer membrane uptake of drug-like molecules, which we combine with a new medium-throughput experimental assay of outer membrane vesicle swelling. Parallel molecular dynamics simulations of compound uptake through Escherichia coli (E. coli) OmpF are used to successfully and quantitatively predict experimental permeabilities measured via either outer membrane swelling or prior liposome-swelling measurements. These simulations are analyzed using an inhomogeneous solubility-diffusion model to yield predictions of permeability. For most polar molecules we test, outer membrane permeability also correlates well with whole-cell uptake. The ability to accurately predict and measure outer membrane uptake of a wide variety of small molecules will enable simpler determination of which molecular scaffolds and which derivatives are most promising prior to extensive chemical synthesis. It will also assist in formulating a more systematic understanding of the chemical determinants of outer membrane permeability.
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Affiliation(s)
- Ricardo J. Ferreira
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
| | - Peter M. Kasson
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, Box 596, 75124 Uppsala, Sweden
- Departments of Biomedical Engineering and Molecular Physiology and Biological Physics, University of Virginia, Box 800886, Charlottesville, Virginia 22908, United States
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Porins and small-molecule translocation across the outer membrane of Gram-negative bacteria. Nat Rev Microbiol 2019; 18:164-176. [DOI: 10.1038/s41579-019-0294-2] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/16/2019] [Indexed: 02/07/2023]
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