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de Oliva BHD, do Nascimento AB, de Oliveira JP, Guidone GHM, Schoeps BL, Silva LC, Barbosa MGL, Montini VH, de Oliveira Junior AG, Rocha SPD. Genomic insights into a Proteus mirabilis strain inducing avian cellulitis. Braz J Microbiol 2024:10.1007/s42770-024-01508-6. [PMID: 39235714 DOI: 10.1007/s42770-024-01508-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 08/28/2024] [Indexed: 09/06/2024] Open
Abstract
Proteus mirabilis, a microorganism distributed in soil, water, and animals, is clinically known for causing urinary tract infections in humans. However, recent studies have linked it to skin infections in broiler chickens, termed avian cellulitis, which poses a threat to animal welfare. While Avian Pathogenic Escherichia coli (APEC) is the primary cause of avian cellulitis, few cases of P. mirabilis involvement are reported, raising questions about the factors facilitating such occurrences. This study employed a pan-genomic approach to investigate whether unique genes exist in P. mirabilis strains causing avian cellulitis. The genome of LBUEL-A33, a P. mirabilis strain known to cause this infection, was assembled, and compared with other P. mirabilis strains isolated from poultry and other sources. Additionally, in silico serogroup analysis was conducted. Results revealed numerous genes unique to the LBUEL-A33 strain. No function in cellulitis was identified for these genes, and in silico investigation of the virulence potential of LBUEL-A33's exclusive proteins proved inconclusive. These findings support that multiple factors are necessary for P. mirabilis to cause avian cellulitis. Furthermore, this species likely employs its own unique arsenal of virulence factors, as many identified mechanisms are analogous to those of E. coli. While antigenic gene clusters responsible for serogroups were identified, no clear trend was observed, and the gene cluster of LBUEL-A33 did not show homology with any sequenced Proteus serogroups. These results reinforce the understanding that this disease is multifactorial, necessitating further research to unravel the mechanisms and underpin the development of control and prevention strategies.
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Affiliation(s)
- Bruno Henrique Dias de Oliva
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | - Arthur Bossi do Nascimento
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | - João Paulo de Oliveira
- Laboratory of Microbial Biotechnology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Londrina, Brazil
| | - Gustavo Henrique Migliorini Guidone
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | - Beatriz Lernic Schoeps
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | - Luana Carvalho Silva
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | - Mario Gabriel Lopes Barbosa
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | - Victor Hugo Montini
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil
| | | | - Sérgio Paulo Dejato Rocha
- Laboratory of Bacteriology, Department of Microbiology, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid, PO-BOX 6001, Londrina, 86051-980, Paraná, Brazil.
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2
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Kavanaugh LG, Dey D, Shafer WM, Conn GL. Structural and functional diversity of Resistance-Nodulation-Division (RND) efflux pump transporters with implications for antimicrobial resistance. Microbiol Mol Biol Rev 2024:e0008923. [PMID: 39235227 DOI: 10.1128/mmbr.00089-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024] Open
Abstract
SUMMARYThe discovery of bacterial efflux pumps significantly advanced our understanding of how bacteria can resist cytotoxic compounds that they encounter. Within the structurally and functionally distinct families of efflux pumps, those of the Resistance-Nodulation-Division (RND) superfamily are noteworthy for their ability to reduce the intracellular concentration of structurally diverse antimicrobials. RND systems are possessed by many Gram-negative bacteria, including those causing serious human disease, and frequently contribute to resistance to multiple antibiotics. Herein, we review the current literature on the structure-function relationships of representative transporter proteins of tripartite RND efflux pumps of clinically important pathogens. We emphasize their contribution to bacterial resistance to clinically used antibiotics, host defense antimicrobials and other biocides, as well as highlighting structural similarities and differences among efflux transporters that help bacteria survive in the face of antimicrobials. Furthermore, we discuss technical advances that have facilitated and advanced efflux pump research and suggest future areas of investigation that will advance antimicrobial development efforts.
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Affiliation(s)
- Logan G Kavanaugh
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
- Graduate Program in Microbiology and Molecular Genetics, Emory University, Atlanta, Georgia, USA
| | - Debayan Dey
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - William M Shafer
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Laboratories of Microbial Pathogenesis, VA Medical Research Service, Veterans Affairs Medical Center, Decatur, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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Bao X, Yang C, Li T, Wang Y, Cui A, Meng X, Huang Q, Li S. Efflux of TolC protein to different antimicrobials can be replaced by other outer membrane proteins with similar β-barrel structures in extraintestinal pathogenic Escherichia coli. J Appl Microbiol 2024; 135:lxae214. [PMID: 39217099 DOI: 10.1093/jambio/lxae214] [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: 02/07/2024] [Revised: 08/06/2024] [Accepted: 08/30/2024] [Indexed: 09/04/2024]
Abstract
AIM As a major efflux pump system in Gram-negative bacteria, AcrAB-TolC plays a key role in the transport of multiple drug substrates and is considered a potential target for the development of novel antimicrobials. Our previous study found that TolC inactivation compromised the resistance to different antimicrobials in porcine extraintestinal pathogenic Escherichia coli (ExPEC) strain PPECC042 (WT). This study was designed to investigate the functional substitution of TolC by other outer membrane proteins (OMPs) with similar β-barrel structures in pumping out different antimicrobials. METHODS AND RESULTS In this study, we found that over-expression of several OMPs with similar β-barrel structures, OmpX, OmpC, OmpN, OmpW, and PhoE, in the ΔtolC strain restored the resistance to macrolides, quinolones, or tetracyclines to the level of WT strain. However, the introduction of any one of the five OMPs did not affect the resistance of the strains ΔacrA, ΔacrB, and ΔacrAΔtolC. Further study revealed that the efflux activity was significantly reduced in the ΔtolC strain, but not in the WT strain and the ΔtolC strains over-expressing various OMPs. Additionally, Nile red dye test and ciprofloxacin accumulation test confirmed that the lost efflux activity and drug accumulation in bacterial periplasm by TolC inactivation was restored by the over-expression of each OMP, depending on the presence of genes acrA and acrB. CONCLUSION All five OMPs can replace the TolC protein to play the efflux role in pumping out the drugs from the periplasm to the extracellular space with the help of proteins AcrA and AcrB.
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Affiliation(s)
- Xue Bao
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Chenglong Yang
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Tian Li
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Yanlin Wang
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Ailian Cui
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Xianrong Meng
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Qi Huang
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Shaowen Li
- Key Laboratory of Preventive Veterinary Medicine in Hubei Province, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
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4
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Cioccolo S, Barritt JD, Pollock N, Hall Z, Babuta J, Sridhar P, Just A, Morgner N, Dafforn T, Gould I, Byrne B. The mycobacterium lipid transporter MmpL3 is dimeric in detergent solution, SMALPs and reconstituted nanodiscs. RSC Chem Biol 2024; 5:901-913. [PMID: 39211474 PMCID: PMC11352979 DOI: 10.1039/d4cb00110a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 07/26/2024] [Indexed: 09/04/2024] Open
Abstract
The mycobacterial membrane protein large 3 (MmpL3) transports key precursor lipids to the outer membrane of Mycobacterium species. Multiple structures of MmpL3 from both M. tuberculosis and M. smegmatis in various conformational states indicate that the protein is both structurally and functionally monomeric. However, most other resistance, nodulation and cell division (RND) transporters structurally characterised to date are either dimeric or trimeric. Here we present an in depth biophysical and computational analysis revealing that MmpL3 from M. smegmatis exists as a dimer in a variety of membrane mimetic systems (SMALPs, detergent-based solution and nanodiscs). Sucrose gradient separation of MmpL3 populations from M. smegmatis, reconstituted into nanodiscs, identified monomeric and dimeric populations of the protein using laser induced liquid bead ion desorption (LILBID), a native mass spectrometry technique. Preliminary cryo-EM analysis confirmed that MmpL3 forms physiological dimers. Untargeted lipidomics experiments on membrane protein co-purified lipids revealed PE and PG lipid classes were predominant. Molecular dynamics (MD) simulations, in the presence of physiologically-relevant lipid compositions revealed the likely dimer interface.
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Affiliation(s)
- Sara Cioccolo
- Department of Life Sciences, Imperial College London Exhibition Road, South Kensington London SW7 2AZ UK
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London Shepherd's Bush London W12 0BZ UK
| | - Joseph D Barritt
- Department of Life Sciences, Imperial College London Exhibition Road, South Kensington London SW7 2AZ UK
| | - Naomi Pollock
- School of Biosciences, University of Birmingham Birmingham UK
| | - Zoe Hall
- Division of Systems Medicine, Imperial College London London UK
| | - Julia Babuta
- Division of Systems Medicine, Imperial College London London UK
| | - Pooja Sridhar
- School of Biosciences, University of Birmingham Birmingham UK
| | - Alicia Just
- Institute of Physical and Theoretical Chemistry, J.W. Goethe-University Frankfurt am Main Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, J.W. Goethe-University Frankfurt am Main Germany
| | - Tim Dafforn
- School of Biosciences, University of Birmingham Birmingham UK
| | - Ian Gould
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London Shepherd's Bush London W12 0BZ UK
| | - Bernadette Byrne
- Department of Life Sciences, Imperial College London Exhibition Road, South Kensington London SW7 2AZ UK
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5
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Roy RK, Bera A, Patra N. Insights into Allosteric Inhibition of the AcrB Efflux Pump: Role of Distinct Binding Pockets, Protomer Preferences, and Crosstalk Disruption. J Chem Inf Model 2024; 64:5964-5976. [PMID: 39011748 DOI: 10.1021/acs.jcim.4c00306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
AcrB, a key component in bacterial efflux processes, exhibits distinct binding pockets that influence inhibitor interactions. In addition to the well-known distal binding pocket within the periplasmic domain, a noteworthy pocket amidst the transmembrane (TM) helices serves as an alternate binding site for inhibitors. The bacterial efflux mechanism involves a pivotal functional rotation of the TM protein, inducing conformational changes in each protomer and propelling drugs toward the outer membrane domain. Surprisingly, inhibitors binding to the TM domain display a preference for L protomers over T protomers. Metadynamics simulations elucidate that Lys940 in the TM domain of AcrB can adopt two conformations in L protomers, whereas the energy barrier for such transitions is higher in T protomers. This phenomenon results in stable inhibitor binding in l protomers. Upon a detailed analysis of unbinding pathways using random accelerated molecular dynamics and umbrella sampling, we have identified three distinct routes for ligand exit from the allosteric site, specifically involving regions within the TM domains─TM4, TM5, and TM10. To explore allosteric crosstalk, we focused on the following key residues: Val452 from the TM domain and Ala831 from the porter domain. Surprisingly, our findings reveal that inhibitor binding disrupts this communication. The shortest path connecting Val452 and Ala831 increases upon inhibitor binding, suggesting sabotage of the natural interdomain communication dynamics. This result highlights the intricate interplay between inhibitor binding and allosteric signaling within our studied system.
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Affiliation(s)
- Rakesh Kumar Roy
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad 826004, India
| | - Abhishek Bera
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad 826004, India
| | - Niladri Patra
- Department of Chemistry and Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad 826004, India
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6
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Singh D, Kumar D, Gayen A, Chandra M. Role of AcrAB-TolC and Its Components in Influx-Efflux Dynamics of QAC Drugs in Escherichia coli Revealed Using SHG Spectroscopy. J Phys Chem Lett 2024:7832-7839. [PMID: 39052610 DOI: 10.1021/acs.jpclett.4c01189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Multidrug efflux pumps, especially those belonging to the class of resistance-nodulation-division (RND), are the key contributors to the rapidly growing multidrug resistance in Gram-negative bacteria. Understanding the role of efflux pumps in real-time drug transport dynamics across the complex dual-cell membrane envelope of Gram-negative bacteria is thus crucial for developing efficient antibiotics against them. Here, we employ second harmonic generation-based nonlinear spectroscopy to study the role of the tripartite efflux pump and its individual components. We systematically investigate the effect of periplasmic adaptor protein AcrA, inner membrane transporter protein AcrB, and outer membrane channel TolC on the overall drug transport in live Acr-type Escherichia coli and its mutant strain cells. Our results reveal that when one of its components is missing, the tripartite AcrAB-TolC efflux pump machinery in Escherichia coli can effectively function as a bipartite system, a fact that has never been demonstrated in live Gram-negative bacteria.
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Affiliation(s)
- Deepak Singh
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Deepak Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Anindita Gayen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
| | - Manabendra Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
- Center of Excellence: Tropical and Infectious Diseases, Gangwal School of Medical Sciences and Technology, Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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Urra G, Valdés-Muñoz E, Suardiaz R, Hernández-Rodríguez EW, Palma JM, Ríos-Rozas SE, Flores-Morales CA, Alegría-Arcos M, Yáñez O, Morales-Quintana L, D’Afonseca V, Bustos D. From Proteome to Potential Drugs: Integration of Subtractive Proteomics and Ensemble Docking for Drug Repurposing against Pseudomonas aeruginosa RND Superfamily Proteins. Int J Mol Sci 2024; 25:8027. [PMID: 39125594 PMCID: PMC11312079 DOI: 10.3390/ijms25158027] [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: 05/27/2024] [Revised: 07/08/2024] [Accepted: 07/17/2024] [Indexed: 08/12/2024] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) poses a significant threat as a nosocomial pathogen due to its robust resistance mechanisms and virulence factors. This study integrates subtractive proteomics and ensemble docking to identify and characterize essential proteins in P. aeruginosa, aiming to discover therapeutic targets and repurpose commercial existing drugs. Using subtractive proteomics, we refined the dataset to discard redundant proteins and minimize potential cross-interactions with human proteins and the microbiome proteins. We identified 12 key proteins, including a histidine kinase and members of the RND efflux pump family, known for their roles in antibiotic resistance, virulence, and antigenicity. Predictive modeling of the three-dimensional structures of these RND proteins and subsequent molecular ensemble-docking simulations led to the identification of MK-3207, R-428, and Suramin as promising inhibitor candidates. These compounds demonstrated high binding affinities and effective inhibition across multiple metrics. Further refinement using non-covalent interaction index methods provided deeper insights into the electronic effects in protein-ligand interactions, with Suramin exhibiting superior binding energies, suggesting its broad-spectrum inhibitory potential. Our findings confirm the critical role of RND efflux pumps in antibiotic resistance and suggest that MK-3207, R-428, and Suramin could be effectively repurposed to target these proteins. This approach highlights the potential of drug repurposing as a viable strategy to combat P. aeruginosa infections.
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Affiliation(s)
- Gabriela Urra
- Laboratorio de Bioinformática y Química Computacional, Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica del Maule, Talca 3480094, Chile; (G.U.); (E.W.H.-R.); (S.E.R.-R.)
| | - Elizabeth Valdés-Muñoz
- Doctorado en Biotecnología Traslacional, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule, Talca 3480094, Chile;
| | - Reynier Suardiaz
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain;
| | - Erix W. Hernández-Rodríguez
- Laboratorio de Bioinformática y Química Computacional, Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica del Maule, Talca 3480094, Chile; (G.U.); (E.W.H.-R.); (S.E.R.-R.)
- Unidad de Bioinformática Clínica, Centro Oncológico, Facultad de Medicina, Universidad Católica del Maule, Talca 3480094, Chile
| | - Jonathan M. Palma
- Facultad de Ingeniería, Universidad de Talca, Curicó 3344158, Chile;
| | - Sofía E. Ríos-Rozas
- Laboratorio de Bioinformática y Química Computacional, Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica del Maule, Talca 3480094, Chile; (G.U.); (E.W.H.-R.); (S.E.R.-R.)
| | | | - Melissa Alegría-Arcos
- Núcleo de Investigación en Data Science, Facultad de Ingeniería y Negocios, Universidad de las Américas, Santiago 7500000, Chile; (M.A.-A.); (O.Y.)
| | - Osvaldo Yáñez
- Núcleo de Investigación en Data Science, Facultad de Ingeniería y Negocios, Universidad de las Américas, Santiago 7500000, Chile; (M.A.-A.); (O.Y.)
| | - Luis Morales-Quintana
- Multidisciplinary Agroindustry Research Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Cinco Pte. N° 1670, Talca 3467987, Chile;
| | - Vívian D’Afonseca
- Departamento de Ciencias Preclínicas, Facultad de Medicina, Universidad Católica del Maule, Ave. San Miguel 3605, Talca 3466706, Chile
| | - Daniel Bustos
- Laboratorio de Bioinformática y Química Computacional, Departamento de Medicina Traslacional, Facultad de Medicina, Universidad Católica del Maule, Talca 3480094, Chile; (G.U.); (E.W.H.-R.); (S.E.R.-R.)
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8
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Klenotic PA, Yu EW. Structural analysis of resistance-nodulation cell division transporters. Microbiol Mol Biol Rev 2024; 88:e0019823. [PMID: 38551344 PMCID: PMC11332337 DOI: 10.1128/mmbr.00198-23] [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] [Indexed: 06/28/2024] Open
Abstract
SUMMARYInfectious bacteria have both intrinsic and acquired mechanisms to combat harmful biocides that enter the cell. Through adaptive pressures, many of these pathogens have become resistant to many, if not all, of the current antibiotics used today to treat these often deadly infections. One prominent mechanism is the upregulation of efflux systems, especially the resistance-nodulation-cell division class of exporters. These tripartite systems consist of an inner membrane transporter coupled with a periplasmic adaptor protein and an outer membrane channel to efficiently transport a diverse array of substrates from inside the cell to the extracellular space. Detailed mechanistic insight into how these inner membrane transporters recognize and shuttle their substrates can ultimately inform both new antibiotic and efflux pump inhibitor design. This review examines the structural basis of substrate recognition of these pumps and the molecular mechanisms underlying multidrug extrusion, which in turn mediate antimicrobial resistance in bacterial pathogens.
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Affiliation(s)
- Philip A. Klenotic
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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9
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Bera A, Mukherjee S, Patra N. Exploring transmembrane allostery in the MexB: DB08385 variant as a promising inhibitor-like candidate against Pseudomonas aeruginosa antibiotic resistance: a computational study. Phys Chem Chem Phys 2024; 26:17011-17027. [PMID: 38835320 DOI: 10.1039/d4cp01620c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Pseudomonas aeruginosa, a formidable pathogen renowned for its antimicrobial resistance, poses a significant threat to immunocompromised individuals. In this regard, the MexAB-OprM efflux pump acts as a pivotal line of defense by extruding antimicrobials from bacterial cells. The inner membrane homotrimeric protein MexB captures antibiotics and translocates them into the outer membrane OprM channel protein connected through the MexA adaptor protein. Despite extensive efforts, competitive inhibitors targeting the tight (T) protomer of the MexB protein have not received FDA approval for medical use. Over the past few years, allosteric inhibitors have become popular as alternatives to the classical competitive inhibitor-based approach because of their higher specificity, lower dosage, and reduced toxicological effects. Hence, in this study, we unveiled the existence of a transmembrane allosteric binding pocket of MexB inspired by the recent discovery of an important allosteric inhibitor, BDM88855, for the homolog AcrB protein. While repurposing BDM88855 proved ineffective in controlling the MexB loose (L) protomer, our investigation identified a promising alternative: a chlorine-containing variant of DB08385 (2-Cl DB08385 or Variant 1). Molecular dynamics simulations, including binding free energy estimation coupled with heterogeneous dielectric implicit membrane model (implicit-membrane MM/PBSA), interaction entropy (IE) analysis and potential of mean force (PMF) calculation, demonstrated Variant 1's superior binding affinity to the transmembrane pocket, displaying the highest energy barrier in the ligand unbinding process. To elucidate the allosteric crosstalk between the transmembrane and porter domain of MexB, we employed the 'eigenvector centrality' measure in the linear mutual information obtained from the protein correlation network. Notably, this study confirmed the presence of an allosteric transmembrane site in the MexB L protomer. In addition to this, Variant 1 emerged as a potent regulator of allosteric crosstalk, inducing an 'O-L intermediate state' in the MexB L protomer. This induced state might hold the potential to diminish substrate intake into the access pocket, leading to the ineffective efflux of antibiotics.
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Affiliation(s)
- Abhishek Bera
- Department of Chemistry & Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad-826004, India.
| | - Shreya Mukherjee
- Department of Chemistry & Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad-826004, India.
| | - Niladri Patra
- Department of Chemistry & Chemical Biology, Indian Institute of Technology (ISM) Dhanbad, Dhanbad-826004, India.
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10
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Lechtenberg T, Wynands B, Müller MF, Polen T, Noack S, Wierckx N. Improving 5-(hydroxymethyl)furfural (HMF) tolerance of Pseudomonas taiwanensis VLB120 by automated adaptive laboratory evolution (ALE). Metab Eng Commun 2024; 18:e00235. [PMID: 38832093 PMCID: PMC11144800 DOI: 10.1016/j.mec.2024.e00235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/29/2024] [Accepted: 05/07/2024] [Indexed: 06/05/2024] Open
Abstract
The aldehyde 5-(hydroxymethyl)furfural (HMF) is of great importance for a circular bioeconomy. It is a renewable platform chemical that can be converted into a range of useful compounds to replace petroleum-based products such as the green plastic monomer 2,5-furandicarboxylic acid (FDCA). However, it also exhibits microbial toxicity for example hindering the efficient biotechnological valorization of lignocellulosic hydrolysates. Thus, there is an urgent need for tolerance-improved organisms applicable to whole-cell biocatalysis. Here, we engineer an oxidation-deficient derivative of the naturally robust and emerging biotechnological workhorse P. taiwanensis VLB120 by robotics-assisted adaptive laboratory evolution (ALE). The deletion of HMF-oxidizing enzymes enabled for the first time evolution under constant selection pressure by the aldehyde, yielding strains with consistently improved growth characteristics in presence of the toxicant. Genome sequencing of evolved clones revealed loss-of function mutations in the LysR-type transcriptional regulator-encoding mexT preventing expression of the associated efflux pump mexEF-oprN. This knowledge allowed reverse engineering of strains with enhanced aldehyde tolerance, even in a background of active or overexpressed HMF oxidation machinery, demonstrating a synergistic effect of two distinct tolerance mechanisms.
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Affiliation(s)
- Thorsten Lechtenberg
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Benedikt Wynands
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Moritz-Fabian Müller
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Tino Polen
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Stephan Noack
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Nick Wierckx
- Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich, 52425 Jülich, Germany
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11
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Novelli M, Bolla JM. RND Efflux Pump Induction: A Crucial Network Unveiling Adaptive Antibiotic Resistance Mechanisms of Gram-Negative Bacteria. Antibiotics (Basel) 2024; 13:501. [PMID: 38927168 PMCID: PMC11200565 DOI: 10.3390/antibiotics13060501] [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: 04/26/2024] [Revised: 05/22/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
The rise of multi-drug-resistant (MDR) pathogenic bacteria presents a grave challenge to global public health, with antimicrobial resistance ranking as the third leading cause of mortality worldwide. Understanding the mechanisms underlying antibiotic resistance is crucial for developing effective treatments. Efflux pumps, particularly those of the resistance-nodulation-cell division (RND) superfamily, play a significant role in expelling molecules from bacterial cells, contributing to the emergence of multi-drug resistance. These are transmembrane transporters naturally produced by Gram-negative bacteria. This review provides comprehensive insights into the modulation of RND efflux pump expression in bacterial pathogens by numerous and common molecules (bile, biocides, pharmaceuticals, additives, plant extracts, etc.). The interplay between these molecules and efflux pump regulators underscores the complexity of antibiotic resistance mechanisms. The clinical implications of efflux pump induction by non-antibiotic compounds highlight the challenges posed to public health and the urgent need for further investigation. By addressing antibiotic resistance from multiple angles, we can mitigate its impact and preserve the efficacy of antimicrobial therapies.
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Affiliation(s)
- Marine Novelli
- Aix Marseille Univ, INSERM, SSA, MCT, 13385 Marseille, France;
- Université Paris Cité, CNRS, Biochimie des Protéines Membranaires, F-75005 Paris, France
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12
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Hamami E, Huo W, Hernandez-Bird J, Castaneda A, Bai J, Syal S, Ortiz-Marquez JC, van Opijnen T, Geisinger E, Isberg RR. Identification of Determinants that Allow Maintenance of High-Level Fluoroquinolone Resistance in Acinetobacter baumannii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.03.560562. [PMID: 38645180 PMCID: PMC11030222 DOI: 10.1101/2023.10.03.560562] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Acinetobacter baumannii is associated with multidrug resistant (MDR) infections in healthcare settings, with fluoroquinolones such as ciprofloxacin being currently ineffective. Clinical isolates largely harbor mutations in the GyrA and TopoIV fluoroquinolone targets, as well as mutations that increase expression of drug resistance-nodulation-division (RND) efflux pumps. Factors critical for maintaining fitness levels of pump overproducers are uncharacterized despite their prevalence in clinical isolates. We here identify proteins that contribute to the fitness of FQR strains overexpressing three known RND systems using high-density insertion mutagenesis. Overproduction of the AdeFGH efflux pump caused hypersensitization to defects in outer membrane homeostatic regulation, including lesions that reduced LOS biosynthesis and blocked production of the major A. baumannii porin. In contrast, AdeAB pump overproduction, which does not affect the outer membrane pump component, was relatively tolerant to loss of these functions, consistent with outer membrane protein overproduction being the primary disruptive component. Surprisingly, overproduction of proton-transporting efflux pumps had little impact on cytosolic pH, consistent with a compensatory response to pump activity. The most striking transcriptional changes were associated with AdeFGH pump overproduction, resulting in activation of the phenylacetate (PAA) degradation regulon. Disruption of the PAA pathway resulted in cytosolic acidification and defective expression of genes involved in protection from peroxide stress. These results indicate that the RND outer membrane protein overproduction is compensated by cytoplasmic buffering and maintenance of outer membrane integrity in A. baumannii to facilitate fitness of FQR isolates.
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Affiliation(s)
- Efrat Hamami
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Wenwen Huo
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Juan Hernandez-Bird
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | | | - Jinna Bai
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Sapna Syal
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
| | - Juan C Ortiz-Marquez
- Department of Biology, Boston College, Chestnut Hill, MA 02135 USA
- Innovation Laboratory, Broad Institute, Cambridge, MA 02412, USA
| | - Tim van Opijnen
- Innovation Laboratory, Broad Institute, Cambridge, MA 02412, USA
| | - Edward Geisinger
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Ralph R Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 150 Harrison Ave., Boston, MA 02111, USA
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13
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Shang Y, Zhang Y, Wang R, Peng Y, Ding B, Liu Y, Li C, Feng L, Liu H, Yang C, Tang Y. Deciphering the molecular and functional basis of TMexCD1: the plasmid-encoded efflux pump of resistance-nodulation-division superfamily. Antimicrob Agents Chemother 2024; 68:e0167823. [PMID: 38477539 PMCID: PMC10989000 DOI: 10.1128/aac.01678-23] [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: 12/20/2023] [Accepted: 02/15/2024] [Indexed: 03/14/2024] Open
Abstract
Horizontal gene transfer has been demonstrated to be an important driver for the emergency of multidrug-resistant pathogens. Recently, a transferable gene cluster tmexCD1-toprJ1 of the resistance-nodulation-division (RND) superfamily was identified in the plasmids of animal-derived Klebsiella pneumoniae strains, with a higher efflux capacity for various drugs than the Escherichia coli AcrAB-TolC homolog system. In this study, we focused on the differences in the inner membrane pump of these two systems and identified some key residues that contribute to the robust efflux activity of the TMexCD1 system. With the aid of homologous modeling and molecular docking, eight residues from the proximal binding pocket (PBP) and nine from the distal binding pocket (DBP) were selected and subjected to site-directed mutagenesis. Several of them, such as S134, I139, D181, and A290, were shown to be important for substrate binding in the DBP region, and all residues in PBP and DBP showed certain substrate preferences. Apart from the conservative switch loop (L613-623TMexD1) previously identified in the E. coli AcrB (EcAcrB), a relatively unconservative loop (L665-675TMexD1) at the bottom of PBP was proposed as a critical element for the robust activity of TMexD1, due to variations at sites E669, G670, N673, and S674 compared to EcAcrAB, and the significantly altered efflux activity due to their mutations. The conservation and flexibility of these key factors can contribute to the evolution of the RND efflux pumps and thus serve as potential targets for developing inhibitors to block the widespread of the TMexCD1 system.
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Affiliation(s)
- Yan Shang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
- Poultry Institute, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Ye Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Ruimin Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yishu Peng
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Bo Ding
- Shandong Institute for Food and Drug Control, Jinan, China
- School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Yuanxiang Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Chongzhou Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Luhua Feng
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Honglei Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Chunyu Yang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yajie Tang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
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14
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Clark R, Newman KE, Khalid S. Titratable residues that drive RND efflux: Insights from molecular simulations. QRB DISCOVERY 2024; 5:e5. [PMID: 38689873 PMCID: PMC11058585 DOI: 10.1017/qrd.2024.6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/04/2024] [Accepted: 03/07/2024] [Indexed: 05/02/2024] Open
Abstract
The resistance-nodulation-division efflux machinery confers antimicrobial resistance to Gram-negative bacteria by actively pumping antibiotics out of the cell. The protein complex is powered by proton motive force; however, the proton transfer mechanism itself and indeed even its stoichiometry is still unclear. Here we review computational studies from the last decade that focus on elucidating the number of protons transferred per conformational cycle of the pump. Given the difficulties in studying proton movement using even state-of-the-art structural biology methods, the contributions from computational studies have been invaluable from a mechanistic perspective.
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Affiliation(s)
- Robert Clark
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Chemistry, University of Southampton, Southampton, UK
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15
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Müh F, Bothe A, Zouni A. Towards understanding the crystallization of photosystem II: influence of poly(ethylene glycol) of various molecular sizes on the micelle formation of alkyl maltosides. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-024-01079-5. [PMID: 38488943 DOI: 10.1007/s11120-024-01079-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 01/24/2024] [Indexed: 03/17/2024]
Abstract
The influence of poly(ethylene glycol) (PEG) polymers H-(O-CH2-CH2)p-OH with different average molecular sizes p on the micelle formation of n-alkyl-β-D-maltoside detergents with the number of carbon atoms in the alkyl chain ranging from 10 to 12 is investigated with the aim to learn more about the detergent behavior under conditions suitable for the crystallization of the photosynthetic pigment-protein complex photosystem II. PEG is shown to increase the critical micelle concentration (CMC) of all three detergents in the crystallization buffer in a way that the free energy of micelle formation increases linearly with the concentration of oxyethylene units (O-CH2-CH2) irrespective of the actual molecular weight of the polymer. The CMC shift is modeled by assuming for simplicity that it is dominated by the interaction between PEG and detergent monomers and is interpreted in terms of an increase of the transfer free energy of a methylene group of the alkyl chain by 0.2 kJ mol-1 per 1 mol L-1 increase of the concentration of oxyethylene units at 298 K. Implications of this effect for the solubilization and crystallization of protein-detergent complexes as well as detergent extraction from crystals are discussed.
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Affiliation(s)
- Frank Müh
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Strasse 69, 4040, Linz, Austria.
| | - Adrian Bothe
- Institut für Molekularbiologie und Biophysik, ETH Zürich, HPK, Otto-Stern-Weg 5, CH-8093, Zurich, Switzerland
| | - Athina Zouni
- Institut für Biologie, Humboldt Universität zu Berlin, Leonor-Michaelis-Haus, Philippstrasse 13, 10095, Berlin, Germany
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16
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Giorgini G, Di Gregorio A, Mangiaterra G, Cedraro N, Minnelli C, Sabbatini G, Mobbili G, Simoni S, Vignaroli C, Galeazzi R. Inhibition of polymorphic MexXY-OprM efflux system in Pseudomonas aeruginosa clinical isolates by Berberine derivatives. ChemMedChem 2024; 19:e202300568. [PMID: 38214500 DOI: 10.1002/cmdc.202300568] [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: 10/20/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/13/2024]
Abstract
The MexXY-OprM multidrug efflux pump (EP) in aminoglycosides resistant Pseudomonas aeruginosa is one of the major resistance mechanisms, which is often overexpressed in strains isolated from pulmonary chronic disease such as cystic fibrosis.[1-3] In this research, we focused on the design of potential efflux pumps inhibitors, targeting MexY, the inner membrane component, in an allosteric site. Berberine[4] has been considered as lead molecule since we previously demonstrated its effectiveness in targeting MexY in laboratory reference strains.[5,6] Since this protein is often present in polymorphic variants in clinical strains, we sequenced and modeled all the mutated forms and we synthesized and evaluated by computational techniques, some berberine derivatives carrying an aromatic functionalization in its 13-C ring position. These compounds were tested in vitro against clinical P. aeruginosa strains for antimicrobial and antibiofilm activity. In conclusion, the results demonstrated the importance of the aromatic moiety functionalization in exerting the EP inhibitory activity in synergy with the aminoglycoside tobramycin. More, we found that aminoacidic composition of MexY in different strains must be considered for predicting potential binding site and affects the different activity of berberine derivatives. Finally, the antibiofilm effect of these new EPIs is promising, particularly for o-CH3-berberine derivative.
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Affiliation(s)
- Giorgia Giorgini
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Alessandra Di Gregorio
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Gianmarco Mangiaterra
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, 61029, Urbino, Italy
| | - Nicholas Cedraro
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Cristina Minnelli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Giulia Sabbatini
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Giovanna Mobbili
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Serena Simoni
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Carla Vignaroli
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
| | - Roberta Galeazzi
- Department of Life and Environmental Sciences, Polytechnic University of Marche, via Brecce Bianche, 60131, Ancona, Italy
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17
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Wilhelm J, Pos KM. Molecular insights into the determinants of substrate specificity and efflux inhibition of the RND efflux pumps AcrB and AdeB. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001438. [PMID: 38358391 PMCID: PMC10924465 DOI: 10.1099/mic.0.001438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/30/2024] [Indexed: 02/16/2024]
Abstract
Gram-negative bacterial members of the Resistance Nodulation and cell Division (RND) superfamily form tripartite efflux pump systems that span the cell envelope. One of the intriguing features of the multiple drug efflux members of this superfamily is their ability to recognize different classes of antibiotics, dyes, solvents, bile salts, and detergents. This review provides an overview of the molecular mechanisms of multiple drug efflux catalysed by the tripartite RND efflux system AcrAB-TolC from Eschericha coli. The determinants for sequential or simultaneous multiple substrate binding and efflux pump inhibitor binding are discussed. A comparison is made with the determinants for substrate binding of AdeB from Acinetobacter baumannii, which acts within the AdeABC multidrug efflux system. There is an apparent general similarity between the structures of AcrB and AdeB and their substrate specificity. However, the presence of distinct conformational states and different drug efflux capacities as revealed by single-particle cryo-EM and mutational analysis suggest that the drug binding and transport features exhibited by AcrB may not be directly extrapolated to the homolog AdeB efflux pump.
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Affiliation(s)
- Julia Wilhelm
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
| | - Klaas Martinus Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
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18
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Niçin RT, Zehir-Şentürk D, Özkan B, Göksungur Y, Şimşek Ö. Optimization of 4,6-α and 4,3-α-Glucanotransferase Production in Lactococcus lactis and Determination of Their Effects on Some Quality Characteristics of Bakery Products. Foods 2024; 13:432. [PMID: 38338567 PMCID: PMC10855804 DOI: 10.3390/foods13030432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/20/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
In this study, the production of 4,6-α (4,6-α-GTase) and 4,3-α-glucanotransferase (4,3-α-GTase), expressed previously in Lactococcus lactis, was optimized and these enzymes were used to investigate glycemic index reduction and staling delay in bakery products. HP-SEC analysis showed that the relevant enzymes were able to produce oligosaccharides from potato starch or malto-oligosaccharides. Response Surface Methodology (RSM) was used to optimize enzyme synthesis and the highest enzyme activities of 15.63 ± 1.65 and 19.01 ± 1.75 U/mL were obtained at 1% glucose, pH 6, and 30 °C for 4,6-α-GTase and 4,3-α-GTase enzymes, respectively. SEM analysis showed that both enzymes reduced the size of the starch granules. These enzymes were purified by ultrafiltration and used to produce bread and bun at an enzyme activity of 4 U/g, resulting in a decrease in the specific volume of the bread. It was found that the estimated glycemic index (eGI) of bread formulated with 4,6-α-GTase decreased by 18.01%, and the eGI of bread prepared with 4,3-α-GTase decreased by 13.61%, indicating a potential delay in staling. No significant differences were observed in the sensory properties of the bakery products. This is the first study showing that 4,6-α-GTase and 4,3-α-GTase enzymes have potential in increasing health benefits and improving technological aspects regarding bakery products.
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Affiliation(s)
- Ramazan Tolga Niçin
- Department of Food Engineering, Faculty of Chemical and Metallurgical Engineering, Yıldız Technical University, Istanbul 34220, Turkey;
| | - Duygu Zehir-Şentürk
- Department of Food Engineering, Faculty of Engineering, Pamukkale University, Denizli 20160, Turkey; (D.Z.-Ş.); (B.Ö.)
| | - Busenur Özkan
- Department of Food Engineering, Faculty of Engineering, Pamukkale University, Denizli 20160, Turkey; (D.Z.-Ş.); (B.Ö.)
| | - Yekta Göksungur
- Department of Food Engineering, Faculty of Engineering, Ege University, İzmir 35100, Turkey;
| | - Ömer Şimşek
- Department of Food Engineering, Faculty of Chemical and Metallurgical Engineering, Yıldız Technical University, Istanbul 34220, Turkey;
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19
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Abstract
In a recent study by Inga V. Leus, Sean R. Roberts, Anhthu Trinh, Edward W. Yu, and Helen I. Zgurskaya (J Bacteriol, 2023, https://doi.org/10.1128/jb.00217-23), it was found that the clinically relevant resistance-nodulation-cell division (RND)-type AdeABC antibiotic efflux pump from Acinetobacter baumannii exhibits close communication between its antibiotic binding sites. Alterations in one of them can have far-reaching impacts on the drug translocation pathway. These insights could reshape our understanding of RND-type efflux pump mechanisms.
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Affiliation(s)
- Klaas Martinus Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Frankfurt, Germany
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20
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Dai JS, Xu J, Shen HJ, Chen NP, Zhu BQ, Xue ZJ, Chen HH, Ding ZS, Ding R, Qian CD. The induced and intrinsic resistance of Escherichia coli to sanguinarine is mediated by AcrB efflux pump. Microbiol Spectr 2024; 12:e0323723. [PMID: 38038452 PMCID: PMC10783092 DOI: 10.1128/spectrum.03237-23] [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: 09/20/2023] [Accepted: 10/31/2023] [Indexed: 12/02/2023] Open
Abstract
IMPORTANCE The use of plant extracts is increasing as an alternative to synthetic compounds, especially antibiotics. However, there is no sufficient knowledge on the mechanisms and potential risks of antibiotic resistance induced by these phytochemicals. In the present study, we found that stable drug resistant mutants of E. coli emerged after repetitive exposure to sanguinarine and demonstrated that the AcrB efflux pump contributed to the emerging of induced and intrinsic resistance of E. coli to this phytochemical. Our results offered some insights into comprehending and preventing the onset of drug-resistant strains when utilizing products containing sanguinarine.
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Affiliation(s)
- Jian-Sheng Dai
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jian Xu
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Hao-Jie Shen
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Ni-Pi Chen
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Bing-Qi Zhu
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zheng-Jie Xue
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Hao-Han Chen
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Zhi-Shan Ding
- College of Medical Technology, Zhejiang Chinese Medical University, Hangzhou, China
| | - Rui Ding
- School of Life Sciences, Anhui Medical University, Hefei, China
| | - Chao-Dong Qian
- College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, China
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21
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Kyono Y, Magboo JD, Daley EA, Flowers SA. Antipsychotic quetiapine alters the mouse fecal resistome by impacting antibiotic efflux, cell membrane, and cell wall synthesis genes. Microbiol Spectr 2024; 12:e0380423. [PMID: 38099619 PMCID: PMC10782992 DOI: 10.1128/spectrum.03804-23] [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: 11/02/2023] [Accepted: 11/16/2023] [Indexed: 01/13/2024] Open
Abstract
IMPORTANCE This study significantly contributes to our understanding of how certain medications can unintentionally contribute to a major global health issue, i.e., antibiotic resistance. Quetiapine, a widely used antipsychotic medication, was found to increase key resistance mechanisms of gut bacteria to antibiotics in mice. Specifically, these data suggest that quetiapine may target elements of the bacterial cell membrane. If similar effects are found in humans, this medicine could unexpectedly make it harder to treat certain infections. This research emphasizes the importance of being mindful about not just antibiotics themselves, but also about other medications that could inadvertently contribute to this problem. Ultimately, these findings underline the necessity for more in-depth research on the broader impact of pharmaceuticals.
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Affiliation(s)
- Yasuhiro Kyono
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Jonathan D. Magboo
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Elizabeth A. Daley
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Stephanie A. Flowers
- Department of Pharmacy Practice, College of Pharmacy, University of Illinois at Chicago, Chicago, Illinois, USA
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22
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Yu Z, Shi X, Wang Z. Structures and Efflux Mechanisms of the AcrAB-TolC Pump. Subcell Biochem 2024; 104:1-16. [PMID: 38963480 DOI: 10.1007/978-3-031-58843-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The global emergence of multidrug resistance (MDR) in gram-negative bacteria has become a matter of worldwide concern. MDR in these pathogens is closely linked to the overexpression of certain efflux pumps, particularly the resistance-nodulation-cell division (RND) efflux pumps. Inhibition of these pumps presents an attractive and promising strategy to combat antibiotic resistance, as the efflux pump inhibitors can effectively restore the potency of existing antibiotics. AcrAB-TolC is one well-studied RND efflux pump, which transports a variety of substrates, therefore providing resistance to a broad spectrum of antibiotics. To develop effective pump inhibitors, a comprehensive understanding of the structural aspect of the AcrAB-TolC efflux pump is imperative. Previous studies on this pump's structure have been limited to individual components or in vitro determination of fully assembled pumps. Recent advancements in cellular cryo-electron tomography (cryo-ET) have provided novel insights into this pump's assembly and functional mechanism within its native cell membrane environment. Here, we present a summary of the structural data regarding the AcrAB-TolC efflux pump, shedding light on its assembly pathway and operational mechanism.
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Affiliation(s)
- Zhili Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Xiaodong Shi
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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23
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Vieira Da Cruz A, Jiménez-Castellanos JC, Börnsen C, Van Maele L, Compagne N, Pradel E, Müller RT, Meurillon V, Soulard D, Piveteau C, Biela A, Dumont J, Leroux F, Deprez B, Willand N, Pos KM, Frangakis AS, Hartkoorn RC, Flipo M. Pyridylpiperazine efflux pump inhibitor boosts in vivo antibiotic efficacy against K. pneumoniae. EMBO Mol Med 2024; 16:93-111. [PMID: 38177534 PMCID: PMC10897476 DOI: 10.1038/s44321-023-00007-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/09/2023] [Accepted: 11/17/2023] [Indexed: 01/06/2024] Open
Abstract
Antimicrobial resistance is a global problem, rendering conventional treatments less effective and requiring innovative strategies to combat this growing threat. The tripartite AcrAB-TolC efflux pump is the dominant constitutive system by which Enterobacterales like Escherichia coli and Klebsiella pneumoniae extrude antibiotics. Here, we describe the medicinal chemistry development and drug-like properties of BDM91288, a pyridylpiperazine-based AcrB efflux pump inhibitor. In vitro evaluation of BDM91288 confirmed it to potentiate the activity of a panel of antibiotics against K. pneumoniae as well as revert clinically relevant antibiotic resistance mediated by acrAB-tolC overexpression. Using cryo-EM, BDM91288 binding to the transmembrane region of K. pneumoniae AcrB was confirmed, further validating the mechanism of action of this inhibitor. Finally, proof of concept studies demonstrated that oral administration of BDM91288 significantly potentiated the in vivo efficacy of levofloxacin treatment in a murine model of K. pneumoniae lung infection.
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Affiliation(s)
- Anais Vieira Da Cruz
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Juan-Carlos Jiménez-Castellanos
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000, Lille, France
| | - Clara Börnsen
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Max-von-Laue-Str. 15, D-60438, Frankfurt am Main, Germany
| | - Laurye Van Maele
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000, Lille, France
| | - Nina Compagne
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Elizabeth Pradel
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000, Lille, France
| | - Reinke T Müller
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438, Frankfurt am Main, Germany
| | - Virginie Meurillon
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Daphnée Soulard
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000, Lille, France
| | - Catherine Piveteau
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Alexandre Biela
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Julie Dumont
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Florence Leroux
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur Lille, US 41-UAR 2014-PLBS, F-59000, Lille, France
| | - Benoit Deprez
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Nicolas Willand
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France
| | - Klaas M Pos
- Institute of Biochemistry, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438, Frankfurt am Main, Germany.
| | - Achilleas S Frangakis
- Buchmann Institute for Molecular Life Sciences and Institute for Biophysics, Goethe University Frankfurt, Max-von-Laue-Str. 15, D-60438, Frankfurt am Main, Germany.
| | - Ruben C Hartkoorn
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019 - UMR 9017 - CIIL - Center for Infection and Immunity of Lille, F-59000, Lille, France.
| | - Marion Flipo
- Univ. Lille, Inserm, Institut Pasteur de Lille, U1177 - Drugs and Molecules for Living Systems, F-59000, Lille, France.
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Mukhopadhyay S, Singh M, Ghosh MM, Chakrabarti S, Ganguli S. Comparative Genomics and Characterization of Shigella flexneri Isolated from Urban Wastewater. Microbes Environ 2024; 39:ME23105. [PMID: 38839365 PMCID: PMC11220449 DOI: 10.1264/jsme2.me23105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 02/22/2024] [Indexed: 06/07/2024] Open
Abstract
Shigella species are a group of highly transmissible Gram-negative pathogens. Increasing reports of infection with extensively drug-resistant varieties of this stomach bug has convinced the World Health Organization to prioritize Shigella for novel therapeutic interventions. We herein coupled the whole-genome sequencing of a natural isolate of Shigella flexneri with a pangenome ana-lysis to characterize pathogen genomics within this species, which will provide us with an insight into its existing genomic diversity and highlight the root causes behind the emergence of quick vaccine escape variants. The isolated novel strain of S. flexneri contained ~4,500 protein-coding genes, 57 of which imparted resistance to antibiotics. A comparative pan-genomic ana-lysis revealed genomic variability of ~64%, the shared conservation of core genes in central metabolic processes, and the enrichment of unique/accessory genes in virulence and defense mechanisms that contributed to much of the observed antimicrobial resistance (AMR). A pathway ana-lysis of the core genome mapped 22 genes to 2 antimicrobial resistance pathways, with the bulk coding for multidrug efflux pumps and two component regulatory systems that are considered to work synergistically towards the development of resistance phenotypes. The prospective evolvability of Shigella species as witnessed by the marked difference in genomic content, the strain-specific essentiality of unique/accessory genes, and the inclusion of a potent resistance mechanism within the core genome, strengthens the possibility of novel serotypes emerging in the near future and emphasizes the importance of tracking down genomic diversity in drug/vaccine design and AMR governance.
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Affiliation(s)
- Sarmishta Mukhopadhyay
- Post Graduate and Research Department of Biotechnology, St. Xavier’s College (Autonomous) Kolkata, West Bengal, India
| | - Meesha Singh
- Post Graduate and Research Department of Microbiology, St. Xavier’s College (Autonomous) Kolkata, West Bengal, India
| | - Mahashweta Mitra Ghosh
- Post Graduate and Research Department of Microbiology, St. Xavier’s College (Autonomous) Kolkata, West Bengal, India
| | - Santanu Chakrabarti
- Department of Zoology, Government General Degree College Singur, Hooghly, West Bengal, India
| | - Sayak Ganguli
- Post Graduate and Research Department of Biotechnology, St. Xavier’s College (Autonomous) Kolkata, West Bengal, India
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25
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Allgood SC, Su CC, Crooks AL, Meyer CT, Zhou B, Betterton MD, Barbachyn MR, Yu EW, Detweiler CS. Bacterial efflux pump modulators prevent bacterial growth in macrophages and under broth conditions that mimic the host environment. mBio 2023; 14:e0249223. [PMID: 37921493 PMCID: PMC10746280 DOI: 10.1128/mbio.02492-23] [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: 09/19/2023] [Accepted: 09/21/2023] [Indexed: 11/04/2023] Open
Abstract
IMPORTANCE Bacterial efflux pumps are critical for resistance to antibiotics and for virulence. We previously identified small molecules that inhibit efflux pumps (efflux pump modulators, EPMs) and prevent pathogen replication in host cells. Here, we used medicinal chemistry to increase the activity of the EPMs against pathogens in cells into the nanomolar range. We show by cryo-electron microscopy that these EPMs bind an efflux pump subunit. In broth culture, the EPMs increase the potency (activity), but not the efficacy (maximum effect), of antibiotics. We also found that bacterial exposure to the EPMs appear to enable the accumulation of a toxic metabolite that would otherwise be exported by efflux pumps. Thus, inhibitors of bacterial efflux pumps could interfere with infection not only by potentiating antibiotics, but also by allowing toxic waste products to accumulate within bacteria, providing an explanation for why efflux pumps are needed for virulence in the absence of antibiotics.
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Affiliation(s)
- Samual C. Allgood
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Amy L. Crooks
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Christian T. Meyer
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado, USA
- Duet Biosystems, Nashville, Tennessee, USA
- Antimicrobial Research Consortium (ARC) Labs, Boulder, Colorado, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado, Boulder, Colorado, USA
| | - Meredith D. Betterton
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
- Department of Physics, University of Colorado, Boulder, Colorado, USA
- Center for Computational Biology, Flatiron Institute, New York, New York, USA
| | | | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Corrella S. Detweiler
- Molecular, Cellular, and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, USA
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26
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Nwabor OF, Chukamnerd A, Terbtothakun P, Nwabor LC, Surachat K, Roytrakul S, Voravuthikunchai SP, Chusri S. Synergistic effects of polymyxin and vancomycin combinations on carbapenem- and polymyxin-resistant Klebsiella pneumoniae and their molecular characteristics. Microbiol Spectr 2023; 11:e0119923. [PMID: 37905823 PMCID: PMC10715205 DOI: 10.1128/spectrum.01199-23] [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: 04/05/2023] [Accepted: 09/27/2023] [Indexed: 11/02/2023] Open
Abstract
IMPORTANCE This study provides insights into the mechanisms of polymyxin resistance in K. pneumoniae clinical isolates and demonstrates potential strategies of polymyxin and vancomycin combinations for combating this resistance. We also identified possible mechanisms that might be associated with the treatment of these combinations against carbapenem- and polymyxin-resistant K. pneumoniae clinical isolates. The findings have significant implications for the development of alternative therapies and the effective management of infections caused by these pathogens.
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Affiliation(s)
- Ozioma Forstinus Nwabor
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Arnon Chukamnerd
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Pawarisa Terbtothakun
- Division of Biological Science, Faculty of Science and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Lois Chinwe Nwabor
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Komwit Surachat
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
- Faculty of Medicine, Translational Medicine Research Center, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Sittiruk Roytrakul
- Functional Proteomics Technology Laboratory, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani, Thailand
| | - Supayang Piyawan Voravuthikunchai
- Faculty of Science, Center of Antimicrobial Biomaterial Innovation-Southeast Asia and Natural Product Research Center of Excellence, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Sarunyou Chusri
- Division of Infectious Diseases, Department of Internal Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
- Department of Biomedical Sciences and Biomedical Engineering, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand
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27
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Pisoni LA, Semple SJ, Liu S, Sykes MJ, Venter H. Combined Structure- and Ligand-Based Approach for the Identification of Inhibitors of AcrAB-TolC in Escherichia coli. ACS Infect Dis 2023; 9:2504-2522. [PMID: 37888944 DOI: 10.1021/acsinfecdis.3c00350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2023]
Abstract
The inhibition of efflux pumps is a promising approach to combating multidrug-resistant bacteria. We have developed a combined structure- and ligand-based model, using OpenEye software, for the identification of inhibitors of AcrB, the inner membrane protein component of the AcrAB-TolC efflux pump in Escherichia coli. From a database of 1391 FDA-approved drugs, 23 compounds were selected to test for efflux inhibition in E. coli. Seven compounds, including ivacaftor (25), butenafine (19), naftifine (27), pimozide (30), thioridazine (35), trifluoperazine (37), and meloxicam (26), enhanced the activity of at least one antimicrobial substrate and inhibited the efflux pump-mediated removal of the substrate Nile Red from cells. Ivacaftor (25) inhibited efflux dose dependently, had no effect on an E. coli strain with genomic deletion of the gene encoding AcrB, and did not damage the bacterial outer membrane. In the presence of a sub-minimum inhibitory concentration (MIC) of the outer membrane permeabilizer colistin, ivacaftor at 1 μg/mL reduced the MICs of erythromycin and minocycline by 4- to 8-fold. The identification of seven potential AcrB inhibitors shows the merits of a combined structure- and ligand-based approach to virtual screening.
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Affiliation(s)
- Lily A Pisoni
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
- Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Susan J Semple
- Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Sida Liu
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Matthew J Sykes
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, South Australia 5000, Australia
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28
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Johnson TS, Bourdine AA, Deber CM. Hydrophobic moment drives penetration of bacterial membranes by transmembrane peptides. J Biol Chem 2023; 299:105266. [PMID: 37734555 PMCID: PMC10585379 DOI: 10.1016/j.jbc.2023.105266] [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: 07/30/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023] Open
Abstract
With antimicrobial resistance (AMR) remaining a persistent and growing threat to human health worldwide, membrane-active peptides are gaining traction as an alternative strategy to overcome the issue. Membrane-embedded multi-drug resistant (MDR) efflux pumps are a prime target for membrane-active peptides, as they are a well-established contributor to clinically relevant AMR infections. Here, we describe a series of transmembrane peptides (TMs) to target the oligomerization motif of the AcrB component of the AcrAB-TolC MDR efflux pump from Escherichia coli. These peptides contain an N-terminal acetyl-A-(Sar)3 (sarcosine; N-methylglycine) tag and a C-terminal lysine tag-a design strategy our lab has utilized to improve the solubility and specificity of targeting for TMs previously. While these peptides have proven useful in preventing AcrB-mediated substrate efflux, the mechanisms by which these peptides associate with and penetrate the bacterial membrane remained unknown. In this study, we have shown peptide hydrophobic moment (μH)-the measure of concentrated hydrophobicity on one face of a lipopathic α-helix-drives bacterial membrane permeabilization and depolarization, likely through lateral-phase separation of negatively-charged POPG lipids and the disruption of lipid packing. Our results show peptide μH is an important consideration when designing membrane-active peptides and may be the determining factor in whether a TM will function in a permeabilizing or non-permeabilizing manner when embedded in the bacterial membrane.
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Affiliation(s)
- Tyler S Johnson
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Aleksandra A Bourdine
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Charles M Deber
- Program in Molecular Medicine, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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29
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Maldonado J, Czarnecka B, Harmon DE, Ruiz C. The multidrug efflux pump regulator AcrR directly represses motility in Escherichia coli. mSphere 2023; 8:e0043023. [PMID: 37787551 PMCID: PMC10597343 DOI: 10.1128/msphere.00430-23] [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: 08/01/2023] [Accepted: 08/18/2023] [Indexed: 10/04/2023] Open
Abstract
Efflux and motility are two key biological functions in bacteria. Recent findings have shown that efflux impacts flagellum biosynthesis and motility in Escherichia coli and other bacteria. AcrR is known to be the major transcriptional repressor of AcrAB-TolC, the main multidrug efflux pump in E. coli and other Enterobacteriaceae. However, the underlying molecular mechanisms of how efflux and motility are co-regulated remain poorly understood. Here, we have studied the role of AcrR in direct regulation of motility in E. coli. By combining bioinformatics, electrophoretic mobility shift assays (EMSAs), gene expression, and motility experiments, we have found that AcrR represses motility in E. coli by directly repressing transcription of the flhDC operon, but not the other flagellum genes/operons tested. flhDC encodes the master regulator of flagellum biosynthesis and motility genes. We found that such regulation primarily occurs by direct binding of AcrR to the flhDC promoter region containing the first of the two predicted AcrR-binding sites identified in this promoter. This is the first report of direct regulation by AcrR of genes unrelated to efflux or detoxification. Moreover, we report that overexpression of AcrR restores to parental levels the increased swimming motility previously observed in E. coli strains without a functional AcrAB-TolC pump, and that such effect by AcrR is prevented by the AcrR ligand and AcrAB-TolC substrate ethidium bromide. Based on these and prior findings, we provide a novel model in which AcrR senses efflux and then co-regulates efflux and motility in E. coli to maintain homeostasis and escape hazards. IMPORTANCE Efflux and motility play a major role in bacterial growth, colonization, and survival. In Escherichia coli, the transcriptional repressor AcrR is known to directly repress efflux and was later found to also repress flagellum biosynthesis and motility by Kim et al. (J Microbiol Biotechnol 26:1824-1828, 2016, doi: 10.4014/jmb.1607.07058). However, it remained unknown whether AcrR represses flagellum biosynthesis and motility directly and through which target genes, or indirectly because of altering the amount of efflux. This study reveals that AcrR represses flagellum biosynthesis and motility by directly repressing the expression of the flhDC master regulator of flagellum biosynthesis and motility genes, but not the other flagellum genes tested. We also show that the antimicrobial, efflux pump substrate, and AcrR ligand ethidium bromide regulates motility via AcrR. Overall, these findings support a novel model of direct co-regulation of efflux and motility mediated by AcrR in response to stress in E. coli.
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Affiliation(s)
- Jessica Maldonado
- Department of Biology, California State University Northridge, Northridge, California, USA
| | - Barbara Czarnecka
- Department of Biology, California State University Northridge, Northridge, California, USA
| | - Dana E. Harmon
- Department of Biology, California State University Northridge, Northridge, California, USA
| | - Cristian Ruiz
- Department of Biology, California State University Northridge, Northridge, California, USA
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30
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Allgood SC, Su CC, Crooks AL, Meyer CT, Zhou B, Betterton MD, Barbachyn MR, Yu EW, Detweiler CS. Bacterial Efflux Pump Modulators Prevent Bacterial Growth in Macrophages and Under Broth Conditions that Mimic the Host Environment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.20.558466. [PMID: 37786697 PMCID: PMC10541609 DOI: 10.1101/2023.09.20.558466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
New approaches for combatting microbial infections are needed. One strategy for disrupting pathogenesis involves developing compounds that interfere with bacterial virulence. A critical molecular determinant of virulence for Gram-negative bacteria are efflux pumps of the resistance-nodulation-division (RND) family, which includes AcrAB-TolC. We previously identified small molecules that bind AcrB, inhibit AcrAB-TolC, and do not appear to damage membranes. These efflux pump modulators (EPMs) were discovered in an in-cell screening platform called SAFIRE (Screen for Anti-infectives using Fluorescence microscopy of IntracellulaR Enterobacteriaceae). SAFIRE identifies compounds that disrupt the growth of a Gram-negative human pathogen, Salmonella enterica serotype Typhimurium (S. Typhimurium) in macrophages. We used medicinal chemistry to iteratively design ~200 EPM35 analogs and test them for activity in SAFIRE, generating compounds with nanomolar potency. Analogs were demonstrated to bind AcrB in a substrate binding pocket by cryo-electron microscopy (cryo-EM). Despite having amphipathic structures, the EPM analogs do not disrupt membrane voltage, as monitored by FtsZ localization to the cell septum. The EPM analogs had little effect on bacterial growth in standard Mueller Hinton Broth. However, under broth conditions that mimic the micro-environment of the macrophage phagosome, acrAB is required for growth, the EPM analogs are bacteriostatic, and increase the potency of antibiotics. These data suggest that under macrophage-like conditions the EPM analogs prevent the export of a toxic bacterial metabolite(s) through AcrAB-TolC. Thus, compounds that bind AcrB could disrupt infection by specifically interfering with the export of bacterial toxic metabolites, host defense factors, and/or antibiotics.
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Affiliation(s)
- Samual C Allgood
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Chih-Chia Su
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Amy L Crooks
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Christian T Meyer
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
- Chemical and Biological Engineering, University of Colorado Boulder, Boulder, CO, USA
- Duet Biosystems, Nashville, TN, USA
- Antimicrobial Research Consortium (ARC) Labs, Boulder, CO, USA
| | - Bojun Zhou
- Department of Physics, University of Colorado, Boulder, CO, USA
| | - Meredith D Betterton
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
- Department of Physics, University of Colorado, Boulder, CO, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
| | | | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- Cleveland Center for Membrane and Structural Biology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Corrella S Detweiler
- Molecular, Cellular Developmental Biology, University of Colorado Boulder, Boulder, CO, USA
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31
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Kavanaugh LG, Mahoney AR, Dey D, Wuest WM, Conn GL. Di-berberine conjugates as chemical probes of Pseudomonas aeruginosa MexXY-OprM efflux function and inhibition. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.24.533986. [PMID: 37425949 PMCID: PMC10327050 DOI: 10.1101/2023.03.24.533986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
The Resistance-Nodulation-Division (RND) efflux pump superfamily is pervasive among Gram-negative pathogens and contributes extensively to clinical antibiotic resistance. The opportunistic pathogen Pseudomonas aeruginosa contains 12 RND-type efflux systems, with four contributing to resistance including MexXY-OprM which is uniquely able to export aminoglycosides. At the site of initial substrate recognition, small molecule probes of the inner membrane transporter (e.g., MexY) have potential as important functional tools to understand substrate selectivity and a foundation for developing adjuvant efflux pump inhibitors (EPIs). Here, we optimized the scaffold of berberine, a known but weak MexY EPI, using an in-silico high-throughput screen to identify di-berberine conjugates with enhanced synergistic action with aminoglycosides. Further, docking and molecular dynamics simulations of di-berberine conjugates reveal unique contact residues and thus sensitivities of MexY from distinct P. aeruginosa strains. This work thereby reveals di-berberine conjugates to be useful probes of MexY transporter function and potential leads for EPI development.
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Affiliation(s)
- Logan G. Kavanaugh
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA
| | | | - Debayan Dey
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA
| | - William M. Wuest
- Department of Chemistry, Emory University, Atlanta, GA
- Emory Antibiotic Resistance Center, Emory University, Atlanta, GA
| | - Graeme L. Conn
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA
- Emory Antibiotic Resistance Center, Emory University, Atlanta, GA
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32
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Shakibaie MR, Modaresi F, Azizi O, Tadjrobehkar O, Ghaemi MM. Amphiphilic peptide Mastoparan-B induces conformational changes within the AdeB efflux pump, down-regulates adeB gene expression, and restores antibiotic susceptibility in an MDR strain of Acinetobacter baumannii. Proteins 2023; 91:1205-1221. [PMID: 37455426 DOI: 10.1002/prot.26539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 05/11/2023] [Accepted: 05/30/2023] [Indexed: 07/18/2023]
Abstract
Mastoparan B (MP-B) is an amphiphilic peptide with a potent antimicrobial activity against most Gram-negative bacteria. However, there is little information available on the inhibition of the Acinetobacter baumannii resistance-nodulation-cell-division (RND) efflux pump using this antimicrobial peptide. Here, we carried out a series of in-silico experiments to find the mechanisms underlying the anti-efflux activity of MP-B using a multi-drug resistant (MDR) strain of A. baumannii (AB). According to our findings, MP-B demonstrated a potent antibacterial activity against an MDR-AB (minimum inhibitory concentration [MIC] = 1 μg/mL) followed by a 20-fold reduction in the adeB gene expression in the presence of sub-MIC of this peptide. Using Groningen Machine for Chemicals Simulation (GROMACS) via PyMOL Graphical User Interface (GUI), (we observed that, the AdeB transporter had conserved helix-turn-helix regions and a tight pore rich in Phe and Ala residues. To understand how inhibition of the AdeB is achieved, we generated 20 apo-MP-B poses using the InterPep and SiteMap tools. The high-quality model was created by homology modeling and used for docking via AutoDock/Vina to identify the MP-B binding sites. We established that the most apo-MP-B formed H-bonds to the backbone of five amino acids in the Helix-5. As a result, the dihedral angles of the involved amino acids shift by 9.0-9.6 Ǻ, causing a change in the conformation of the AdeB protein. This led to helix conformation stereoisomerization and block the AdeB activity. MP-B presumably has dual mechanisms. (1) It blocks the AdeB transporter by changing its conformation. (2) MP-B influences the adeB gene expression by binding to G-protein which laterally controls efflux regulators like MarA, RamA, SoxS, and Rob proteins.
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Affiliation(s)
- Mohammad Reza Shakibaie
- Department of Microbiology and Virology, Kerman University of Medical Sciences, Kerman, Iran
- Gastroenterology Hepatology Research Center, Institute of Basic and Clinical Physiology, Kerman University of Medical Sciences, Kerman, Iran
| | - Farzan Modaresi
- Department of Microbiology, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran
| | - Omid Azizi
- Department of Laboratory Sciences, and Health Sciences Research center, Torbat Heydariyeh University of Medical Sciences, Torbate Heydarieh, Iran
| | - Omid Tadjrobehkar
- Department of Microbiology and Virology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Mehdi Ghaemi
- Medical Informatics Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran
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Zhang Z, Lizer N, Wu Z, Morgan CE, Yan Y, Zhang Q, Yu EW. Cryo-Electron Microscopy Structures of a Campylobacter Multidrug Efflux Pump Reveal a Novel Mechanism of Drug Recognition and Resistance. Microbiol Spectr 2023; 11:e0119723. [PMID: 37289051 PMCID: PMC10434076 DOI: 10.1128/spectrum.01197-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 05/18/2023] [Indexed: 06/09/2023] Open
Abstract
Campylobacter jejuni is a bacterium that is commonly present in the intestinal tracts of animals. It is also a major foodborne pathogen that causes gastroenteritis in humans. The most predominant and clinically important multidrug efflux system in C. jejuni is the CmeABC (Campylobacter multidrug efflux) pump, a tripartite system that includes an inner membrane transporter (CmeB), a periplasmic fusion protein (CmeA), and an outer membrane channel protein (CmeC). This efflux protein machinery mediates resistance to a number of structurally diverse antimicrobial agents. A recently identified CmeB variant, termed resistance enhancing CmeB (RE-CmeB), can increase its multidrug efflux pump activity, likely by influencing antimicrobial recognition and extrusion. Here, we report structures of RE-CmeB in its apo form as well as in the presence of four different drugs by using single-particle cryo-electron microscopy (cryo-EM). Coupled with mutagenesis and functional studies, this structural information allows us to identify critical amino acids that are important for drug resistance. We also report that RE-CmeB utilizes a somewhat unique subset of residues to bind different drugs, thereby optimizing its ability to accommodate different compounds with distinct scaffolds. These findings provide insights into the structure-function relationship of this newly emerged antibiotic efflux transporter variant in Campylobacter. IMPORTANCE Campylobacter jejuni has emerged as one of the most problematic and highly antibiotic-resistant pathogens, worldwide. The Centers for Disease Control and Prevention have designated antibiotic-resistant C. jejuni as a serious antibiotic resistance threat in the United States. We recently identified a C. jejuni resistance enhancing CmeB (RE-CmeB) variant that can increase its multidrug efflux pump activity and confers an exceedingly high-level of resistance to fluoroquinolones. Here, we report the cryo-EM structures of this prevalent and clinically important C. jejuni RE-CmeB multidrug efflux pump in both the absence and presence of four antibiotics. These structures allow us to understand the action mechanism for multidrug recognition in this pump. Our studies will ultimately inform an era in structure-guided drug design to combat multidrug resistance in these Gram-negative pathogens.
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Affiliation(s)
- Zhemin Zhang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Nicholas Lizer
- Department of Veterinary Microbiology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Zuowei Wu
- Department of Veterinary Microbiology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Christopher E. Morgan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Yuqi Yan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Qijing Zhang
- Department of Veterinary Microbiology, College of Veterinary Medicine, Iowa State University, Ames, Iowa, USA
| | - Edward W. Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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Avakh A, Grant GD, Cheesman MJ, Kalkundri T, Hall S. The Art of War with Pseudomonas aeruginosa: Targeting Mex Efflux Pumps Directly to Strategically Enhance Antipseudomonal Drug Efficacy. Antibiotics (Basel) 2023; 12:1304. [PMID: 37627724 PMCID: PMC10451789 DOI: 10.3390/antibiotics12081304] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/26/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) poses a grave clinical challenge due to its multidrug resistance (MDR) phenotype, leading to severe and life-threatening infections. This bacterium exhibits both intrinsic resistance to various antipseudomonal agents and acquired resistance against nearly all available antibiotics, contributing to its MDR phenotype. Multiple mechanisms, including enzyme production, loss of outer membrane proteins, target mutations, and multidrug efflux systems, contribute to its antimicrobial resistance. The clinical importance of addressing MDR in P. aeruginosa is paramount, and one pivotal determinant is the resistance-nodulation-division (RND) family of drug/proton antiporters, notably the Mex efflux pumps. These pumps function as crucial defenders, reinforcing the emergence of extensively drug-resistant (XDR) and pandrug-resistant (PDR) strains, which underscores the urgency of the situation. Overcoming this challenge necessitates the exploration and development of potent efflux pump inhibitors (EPIs) to restore the efficacy of existing antipseudomonal drugs. By effectively countering or bypassing efflux activities, EPIs hold tremendous potential for restoring the antibacterial activity against P. aeruginosa and other Gram-negative pathogens. This review focuses on concurrent MDR, highlighting the clinical significance of efflux pumps, particularly the Mex efflux pumps, in driving MDR. It explores promising EPIs and delves into the structural characteristics of the MexB subunit and its substrate binding sites.
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Affiliation(s)
| | | | | | | | - Susan Hall
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia; (A.A.); (G.D.G.); (M.J.C.); (T.K.)
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Kato T, Okada U, Hung LW, Yamashita E, Kim HB, Kim CY, Terwilliger TC, Schweizer HP, Murakami S. Crystal structures of multidrug efflux transporters from Burkholderia pseudomallei suggest details of transport mechanism. Proc Natl Acad Sci U S A 2023; 120:e2215072120. [PMID: 37428905 PMCID: PMC10629574 DOI: 10.1073/pnas.2215072120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 05/24/2023] [Indexed: 07/12/2023] Open
Abstract
BpeB and BpeF are multidrug efflux transporters from Burkholderia pseudomallei that enable multidrug resistance. Here, we report the crystal structures of BpeB and BpeF at 2.94 Å and 3.0 Å resolution, respectively. BpeB was found as an asymmetric trimer, consistent with the widely-accepted functional rotation mechanism for this type of transporter. One of the monomers has a distinct structure that we interpret as an intermediate along this functional cycle. Additionally, a detergent molecule bound in a previously undescribed binding site provides insights into substrate translocation through the pathway. BpeF shares structural similarities with the crystal structure of OqxB from Klebsiella pneumoniae, where both are symmetric trimers composed of three "binding"-state monomers. The structures of BpeB and BpeF further our understanding of the functional mechanisms of transporters belonging to the HAE1-RND superfamily.
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Affiliation(s)
- Takaaki Kato
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama226-8501, Japan
| | - Ui Okada
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama226-8501, Japan
| | - Li-Wei Hung
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM87545
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, Osaka565-0871, Japan
| | - Heung-Bok Kim
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM87545
| | - Chang-Yub Kim
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM87545
| | - Thomas C. Terwilliger
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM87545
- New Mexico Consortium, Los Alamos, NM87544
| | - Herbert P. Schweizer
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ86011
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ86011
| | - Satoshi Murakami
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama226-8501, Japan
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Yamasaki S, Zwama M, Yoneda T, Hayashi-Nishino M, Nishino K. Drug resistance and physiological roles of RND multidrug efflux pumps in Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001322. [PMID: 37319001 PMCID: PMC10333786 DOI: 10.1099/mic.0.001322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 03/18/2023] [Indexed: 06/17/2023]
Abstract
Drug efflux pumps transport antimicrobial agents out of bacteria, thereby reducing the intracellular antimicrobial concentration, which is associated with intrinsic and acquired bacterial resistance to these antimicrobials. As genome analysis has advanced, many drug efflux pump genes have been detected in the genomes of bacterial species. In addition to drug resistance, these pumps are involved in various essential physiological functions, such as bacterial adaptation to hostile environments, toxin and metabolite efflux, biofilm formation and quorum sensing. In Gram-negative bacteria, efflux pumps in the resistance–nodulation–division (RND) superfamily play a clinically important role. In this review, we focus on Gram-negative bacteria, including Salmonella enterica , Escherichia coli and Pseudomonas aeruginosa , and discuss the role of RND efflux pumps in drug resistance and physiological functions.
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Affiliation(s)
- Seiji Yamasaki
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Institute for Advanced Co-Creation Studies, Osaka University, 1-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Martijn Zwama
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Tomohiro Yoneda
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mitsuko Hayashi-Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Kunihiko Nishino
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
- Center for Infectious Disease Education and Research, 2-8 Yamadaoka, Osaka University, Suita, Osaka 565-0871, Japan
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37
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Jang S. AcrAB-TolC, a major efflux pump in Gram negative bacteria: toward understanding its operation mechanism. BMB Rep 2023; 56:326-334. [PMID: 37254571 PMCID: PMC10315565 DOI: 10.5483/bmbrep.2023-0070] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/18/2023] [Accepted: 05/30/2023] [Indexed: 08/27/2023] Open
Abstract
Antibiotic resistance (AR) is a silent pandemic that kills millions worldwide. Although the development of new therapeutic agents against antibiotic resistance is in urgent demand, this has presented a great challenge, especially for Gram-negative bacteria that have inherent drug-resistance mediated by impermeable outer membranes and multidrug efflux pumps that actively extrude various drugs from the bacteria. For the last two decades, multidrug efflux pumps, including AcrAB-TolC, the most clinically important efflux pump in Gram-negative bacteria, have drawn great attention as strategic targets for re-sensitizing bacteria to the existing antibiotics. This article aims to provide a concise overview of the AcrAB-TolC operational mechanism, reviewing its architecture and substrate specificity, as well as the recent development of AcrAB-TolC inhibitors. [BMB Reports 2023; 56(6): 326-334].
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Affiliation(s)
- Soojin Jang
- Department of Discovery Biology, Antibacterial Resistance Laboratory, Institut Pasteur Korea, Seongnam 13488, Korea
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38
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De Gaetano GV, Lentini G, Famà A, Coppolino F, Beninati C. Antimicrobial Resistance: Two-Component Regulatory Systems and Multidrug Efflux Pumps. Antibiotics (Basel) 2023; 12:965. [PMID: 37370284 DOI: 10.3390/antibiotics12060965] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
The number of multidrug-resistant bacteria is rapidly spreading worldwide. Among the various mechanisms determining resistance to antimicrobial agents, multidrug efflux pumps play a noteworthy role because they export extraneous and noxious substrates from the inside to the outside environment of the bacterial cell contributing to multidrug resistance (MDR) and, consequently, to the failure of anti-infective therapies. The expression of multidrug efflux pumps can be under the control of transcriptional regulators and two-component systems (TCS). TCS are a major mechanism by which microorganisms sense and reply to external and/or intramembrane stimuli by coordinating the expression of genes involved not only in pathogenic pathways but also in antibiotic resistance. In this review, we describe the influence of TCS on multidrug efflux pump expression and activity in some Gram-negative and Gram-positive bacteria. Taking into account the strict correlation between TCS and multidrug efflux pumps, the development of drugs targeting TCS, alone or together with already discovered efflux pump inhibitors, may represent a beneficial strategy to contribute to the fight against growing antibiotic resistance.
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Affiliation(s)
| | - Germana Lentini
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
| | - Agata Famà
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
| | - Francesco Coppolino
- Department of Biomedical, Dental and Imaging Sciences, University of Messina, 98124 Messina, Italy
| | - Concetta Beninati
- Department of Human Pathology, University of Messina, 98124 Messina, Italy
- Scylla Biotech Srl, 98124 Messina, Italy
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Almeida MC, Szemerédi N, Durães F, Long S, Resende DISP, Martins da Costa P, Pinto M, Spengler G, Sousa E. Effect of Indole-Containing Pyrazino[2,1- b]quinazoline-3,6-diones in the Virulence of Resistant Bacteria. Antibiotics (Basel) 2023; 12:antibiotics12050922. [PMID: 37237825 DOI: 10.3390/antibiotics12050922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
Drug resistance is rising to alarming levels, constituting one of the major threats to global health. The overexpression of efflux pumps and the formation of biofilms constitute two of the most common resistance mechanisms, favoring the virulence of bacteria. Therefore, the research and development of effective antimicrobial agents that can also counteract resistance mechanisms are extremely important. Pyrazino[2,1-b]quinazoline-3,6-diones, from marine and terrestrial organisms and simpler synthetic analogues, were recently disclosed by us as having relevant antimicrobial properties. In this study, using a multi-step approach, it was possible to synthesize new pyrazino[2,1-b]quinazoline-3,6-diones focusing on compounds with fluorine substituents since, to the best of our knowledge, the synthesis of fluorinated fumiquinazoline derivatives had not been attempted before. The new synthesized derivatives were screened for antibacterial activity and, along with previously synthetized pyrazino[2,1-b]quinazoline-3,6-diones, were characterized for their antibiofilm and efflux-pump-inhibiting effects against representative bacterial species and relevant resistant clinical strains. Several compounds showed relevant antibacterial activity against the tested Gram-positive bacterial species with MIC values in the range of 12.5-77 μM. Furthermore, some derivatives showed promising results as antibiofilm agents in a crystal violet assay. The results of the ethidium bromide accumulation assay suggested that some compounds could potentially inhibit bacterial efflux pumps.
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Affiliation(s)
- Mariana C Almeida
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Nikoletta Szemerédi
- Department of Medical Microbiology, Albert Szent-Gyorgyi Health Center and Albert Szent-Gyorgyi Medical School, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary
| | - Fernando Durães
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Solida Long
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- Department of Bioengineering, Royal University of Phnom Penh, Russian Confederation Blvd, Phnom Penh 12156, Cambodia
| | - Diana I S P Resende
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Paulo Martins da Costa
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
- ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Madalena Pinto
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
| | - Gabriella Spengler
- Department of Medical Microbiology, Albert Szent-Gyorgyi Health Center and Albert Szent-Gyorgyi Medical School, University of Szeged, Semmelweis utca 6, 6725 Szeged, Hungary
| | - Emília Sousa
- Laboratório de Química Orgânica e Farmacêutica, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
- CIIMAR--Centro Interdisciplinar de Investigação Marinha e Ambiental, Terminal de Cruzeiros do Porto de Leixões, 4450-208 Matosinhos, Portugal
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40
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Trampari E, Prischi F, Vargiu AV, Abi-Assaf J, Bavro VN, Webber MA. Functionally distinct mutations within AcrB underpin antibiotic resistance in different lifestyles. NPJ ANTIMICROBIALS AND RESISTANCE 2023; 1:2. [PMID: 38686215 PMCID: PMC11057200 DOI: 10.1038/s44259-023-00001-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/27/2023] [Indexed: 05/02/2024]
Abstract
Antibiotic resistance is a pressing healthcare challenge and is mediated by various mechanisms, including the active export of drugs via multidrug efflux systems, which prevent drug accumulation within the cell. Here, we studied how Salmonella evolved resistance to two key antibiotics, cefotaxime and azithromycin, when grown planktonically or as a biofilm. Resistance to both drugs emerged in both conditions and was associated with different substitutions within the efflux-associated transporter, AcrB. Azithromycin exposure selected for an R717L substitution, while cefotaxime for Q176K. Additional mutations in ramR or envZ accumulated concurrently with the R717L or Q176K substitutions respectively, resulting in clinical resistance to the selective antibiotics and cross-resistance to other drugs. Structural, genetic, and phenotypic analysis showed the two AcrB substitutions confer their benefits in profoundly different ways. R717L reduces steric barriers associated with transit through the substrate channel 2 of AcrB. Q176K increases binding energy for cefotaxime, improving recognition in the distal binding pocket, resulting in increased efflux efficiency. Finally, we show the R717 substitution is present in isolates recovered around the world.
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Affiliation(s)
- Eleftheria Trampari
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ UK
| | - Filippo Prischi
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ UK
| | - Attilio V. Vargiu
- Department of Physics, University of Cagliari, S. P. 8, km. 0.700, 09042 Monserrato, Italy
| | - Justin Abi-Assaf
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ UK
| | - Vassiliy N. Bavro
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ UK
| | - Mark A. Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, Norfolk NR4 7UQ UK
- Medical School, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7UA UK
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41
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Meier G, Thavarasah S, Ehrenbolger K, Hutter CAJ, Hürlimann LM, Barandun J, Seeger MA. Deep mutational scan of a drug efflux pump reveals its structure-function landscape. Nat Chem Biol 2023; 19:440-450. [PMID: 36443574 PMCID: PMC7615509 DOI: 10.1038/s41589-022-01205-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 10/10/2022] [Indexed: 11/30/2022]
Abstract
Drug efflux is a common resistance mechanism found in bacteria and cancer cells, but studies providing comprehensive functional insights are scarce. In this study, we performed deep mutational scanning (DMS) on the bacterial ABC transporter EfrCD to determine the drug efflux activity profile of more than 1,430 single variants. These systematic measurements revealed that the introduction of negative charges at different locations within the large substrate binding pocket results in strongly increased efflux activity toward positively charged ethidium, whereas additional aromatic residues did not display the same effect. Data analysis in the context of an inward-facing cryogenic electron microscopy structure of EfrCD uncovered a high-affinity binding site, which releases bound drugs through a peristaltic transport mechanism as the transporter transits to its outward-facing conformation. Finally, we identified substitutions resulting in rapid Hoechst influx without affecting the efflux activity for ethidium and daunorubicin. Hence, single mutations can convert EfrCD into a drug-specific ABC importer.
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Affiliation(s)
- Gianmarco Meier
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Sujani Thavarasah
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Kai Ehrenbolger
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Cedric A J Hutter
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Linkster Therapeutics AG, Zurich, Switzerland
| | - Lea M Hürlimann
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- Linkster Therapeutics AG, Zurich, Switzerland
| | - Jonas Barandun
- Laboratory for Molecular Infection Medicine Sweden (MIMS), Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
- Science for Life Laboratory, Umeå University, Umeå, Sweden
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland.
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Guo T, Chen Y, Chen W, Semple SJ, Gu X, Polyak SW, Sun G, Venter H, Ma S. Design and synthesis of benzochromene derivatives as AcrB inhibitors for the reversal of bacterial multidrug resistance. Eur J Med Chem 2023; 249:115148. [PMID: 36709649 DOI: 10.1016/j.ejmech.2023.115148] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/17/2023] [Accepted: 01/22/2023] [Indexed: 01/26/2023]
Abstract
A series of novel benzo[h]chromene compounds were designed, synthesized and evaluated for their biological activity as AcrB inhibitors. The compounds were assessed for their ability to potentiate the effect of antibiotics. Compounds with antibiotic-potentiating effects were then evaluated for inhibition of Nile Red efflux, and for off-target effects including activity on the outer and inner bacterial membranes and toxicity. Six compounds were identified to reduce the MIC values of at least one of the tested antibiotics by at least 4-fold, and further reduced the MICs in the presence of a membrane permeabilizer. The identified compounds were also able to inhibit Nile Red efflux at concentrations between 50 μM and 200 μM. The compounds did not disrupt the bacterial outer membrane nor display toxicity in a nematode model (Caenorhabditis elegans). The 4-methoxyphenoxy)propoxy derivative compound G6 possessed the most potent antibacterial potentiation with erythromycin by 8-fold even without the presence of a membrane permeabilizer. Furthermore, H6, G6, G10 and G11 completely abolished the Nile Red efflux at a concentration of 50 μM. The 3,4-dihydro-2H-benzo[h]chromen-5-yl)(morpholino)methanone core appears to be a promising chemical skeleton to be further studied in the discovery of more putative AcrB inhibitors.
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Affiliation(s)
- Ting Guo
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Yang Chen
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Weijin Chen
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Susan J Semple
- Quality Use of Medicines and Pharmacy Research Centre, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Xiaotong Gu
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Steven W Polyak
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia
| | - Guanglin Sun
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, 5000, Australia.
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, 250012, China.
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43
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Athar M, Gervasoni S, Catte A, Basciu A, Malloci G, Ruggerone P, Vargiu AV. Tripartite efflux pumps of the RND superfamily: what did we learn from computational studies? MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 36972322 DOI: 10.1099/mic.0.001307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Bacterial resistance to antibiotics has been long recognized as a priority to address for human health. Among all micro-organisms, the so-called multi-drug resistant (MDR) bacteria, which are resistant to most, if not all drugs in our current arsenal, are particularly worrisome. The World Health Organization has prioritized the ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species) pathogens, which include four Gram-negative bacterial species. In these bacteria, active extrusion of antimicrobial compounds out of the cell by means of 'molecular guns' known as efflux pumps is a main determinant of MDR phenotypes. The resistance-nodulation-cell division (RND) superfamily of efflux pumps connecting the inner and outer membrane in Gram-negative bacteria is crucial to the onset of MDR and virulence, as well as biofilm formation. Thus, understanding the molecular basis of the interaction of antibiotics and inhibitors with these pumps is key to the design of more effective therapeutics. With the aim to contribute to this challenge, and complement and inspire experimental research, in silico studies on RND efflux pumps have flourished in recent decades. Here, we review a selection of such investigations addressing the main determinants behind the polyspecificity of these pumps, the mechanisms of substrate recognition, transport and inhibition, as well as the relevance of their assembly for proper functioning, and the role of protein-lipid interactions. The journey will end with a perspective on the role of computer simulations in addressing the challenges posed by these beautifully complex machineries and in supporting the fight against the spread of MDR bacteria.
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Affiliation(s)
- Mohd Athar
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Silvia Gervasoni
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Andrea Catte
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Andrea Basciu
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Giuliano Malloci
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Paolo Ruggerone
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
| | - Attilio Vittorio Vargiu
- Physics Department, University of Cagliari, Cittadella Universitaria, SP 8 km 0.700, 09042, Monserrato (CA), Italy
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Cryo-EM Structures of AcrD Illuminate a Mechanism for Capturing Aminoglycosides from Its Central Cavity. mBio 2023; 14:e0338322. [PMID: 36625574 PMCID: PMC9973356 DOI: 10.1128/mbio.03383-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The Escherichia coli acriflavine resistance protein D (AcrD) is an efflux pump that belongs to the resistance-nodulation-cell division (RND) superfamily. Its primary function is to provide resistance to aminoglycoside-based drugs by actively extruding these noxious compounds out of E. coli cells. AcrD can also mediate resistance to a limited range of other amphiphilic agents, including bile acids, novobiocin, and fusidic acids. As there is no structural information available for any aminoglycoside-specific RND pump, here we describe cryo-electron microscopy (cryo-EM) structures of AcrD in the absence and presence of bound gentamicin. These structures provide new information about the RND superfamily of efflux pumps, specifically, that three negatively charged residues central to the aminoglycoside-binding site are located within the ceiling of the central cavity of the AcrD trimer. Thus, it is likely that AcrD is capable of picking up aminoglycosides via this central cavity. Through the combination of cryo-EM structural determination, mutagenesis analysis, and molecular simulation, we show that charged residues are critically important for this pump to shuttle drugs directly from the central cavity to the funnel of the AcrD trimer for extrusion. IMPORTANCE Here, we report cryo-EM structures of the AcrD aminoglycoside efflux pump in the absence and presence of bound gentamicin, posing the possibility that this pump is capable of capturing aminoglycosides from the central cavity of the AcrD trimer. The results indicate that AcrD utilizes charged residues to bind and export drugs, mediating resistance to these antibiotics.
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RND Pump-Mediated Efflux of Amotosalen, a Compound Used in Pathogen Inactivation Technology to Enhance Safety of Blood Transfusion Products, May Compromise Its Gram-Negative Anti-Bacterial Activity. mSphere 2023; 8:e0067322. [PMID: 36853056 PMCID: PMC10117049 DOI: 10.1128/msphere.00673-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
Pathogen inactivation is a strategy to improve the safety of transfusion products. The only pathogen reduction technology for blood products currently approved in the US utilizes a psoralen compound, called amotosalen, in combination with UVA light to inactivate bacteria, viruses, and protozoa. Psoralens have structural similarity to bacterial multidrug efflux pump substrates. As these efflux pumps are often overexpressed in multidrug-resistant pathogens, we tested whether contemporary drug-resistant pathogens might show resistance to amotosalen and other psoralens based on multidrug efflux mechanisms through genetic, biophysical, and molecular modeling analysis. The main efflux systems in Enterobacterales, Acinetobacter baumannii, and Pseudomonas aeruginosa are tripartite resistance-nodulation-cell division (RND) systems, which span the inner and outer membranes of Gram-negative pathogens, and expel antibiotics from the bacterial cytoplasm into the extracellular space. We provide evidence that amotosalen is an efflux substrate for the E. coli AcrAB, Acinetobacter baumannii AdeABC, and P. aeruginosa MexXY RND efflux pumps. Furthermore, we show that the MICs for contemporary Gram-negative bacterial isolates for these species and others in vitro approached and exceeded the concentration of amotosalen used in the approved platelet and plasma inactivation procedures. These findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens. IMPORTANCE Pathogen inactivation is a strategy to enhance the safety of transfused blood products. We identify the compound, amotosalen, widely used for pathogen inactivation, as a bacterial multidrug efflux substrate. Specifically, experiments suggest that amotosalen is pumped out of bacteria by major efflux pumps in E. coli, Acinetobacter baumannii, and Pseudomonas aeruginosa. Such efflux pumps are often overexpressed in multidrug-resistant pathogens. Importantly, the MICs for contemporary multidrug-resistant Enterobacterales, Acinetobacter baumannii, Pseudomonas aeruginosa, Burkholderia spp., and Stenotrophomonas maltophilia isolates approached or exceeded the amotosalen concentration used in approved platelet and plasma inactivation procedures, potentially as a result of efflux pump activity. Although there are important differences in methodology between our experiments and blood product pathogen inactivation, these findings suggest that otherwise safe and effective inactivation methods should be further studied to identify possible gaps in their ability to inactivate contemporary, multidrug-resistant bacterial pathogens.
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Si Z, Pethe K, Chan-Park MB. Chemical Basis of Combination Therapy to Combat Antibiotic Resistance. JACS AU 2023; 3:276-292. [PMID: 36873689 PMCID: PMC9975838 DOI: 10.1021/jacsau.2c00532] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 06/10/2023]
Abstract
The antimicrobial resistance crisis is a global health issue requiring discovery and development of novel therapeutics. However, conventional screening of natural products or synthetic chemical libraries is uncertain. Combination therapy using approved antibiotics with inhibitors targeting innate resistance mechanisms provides an alternative strategy to develop potent therapeutics. This review discusses the chemical structures of effective β-lactamase inhibitors, outer membrane permeabilizers, and efflux pump inhibitors that act as adjuvant molecules of classical antibiotics. Rational design of the chemical structures of adjuvants will provide methods to impart or restore efficacy to classical antibiotics for inherently antibiotic-resistant bacteria. As many bacteria have multiple resistance pathways, adjuvant molecules simultaneously targeting multiple pathways are promising approaches to combat multidrug-resistant bacterial infections.
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Affiliation(s)
- Zhangyong Si
- School
of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459
| | - Kevin Pethe
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921
- Singapore
Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore 637551
| | - Mary B. Chan-Park
- School
of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore 637459
- Lee
Kong Chian School of Medicine, Nanyang Technological
University, Singapore 636921
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Update on the Discovery of Efflux Pump Inhibitors against Critical Priority Gram-Negative Bacteria. Antibiotics (Basel) 2023; 12:antibiotics12010180. [PMID: 36671381 PMCID: PMC9854755 DOI: 10.3390/antibiotics12010180] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/18/2023] Open
Abstract
Antimicrobial resistance (AMR) has become a major problem in public health leading to an estimated 4.95 million deaths in 2019. The selective pressure caused by the massive and repeated use of antibiotics has led to bacterial strains that are partially or even entirely resistant to known antibiotics. AMR is caused by several mechanisms, among which the (over)expression of multidrug efflux pumps plays a central role. Multidrug efflux pumps are transmembrane transporters, naturally expressed by Gram-negative bacteria, able to extrude and confer resistance to several classes of antibiotics. Targeting them would be an effective way to revive various options for treatment. Many efflux pump inhibitors (EPIs) have been described in the literature; however, none of them have entered clinical trials to date. This review presents eight families of EPIs active against Escherichia coli or Pseudomonas aeruginosa. Structure-activity relationships, chemical synthesis, in vitro and in vivo activities, and pharmacological properties are reported. Their binding sites and their mechanisms of action are also analyzed comparatively.
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Biou V. Lipid-membrane protein interaction visualised by cryo-EM: A review. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184068. [PMID: 36216098 DOI: 10.1016/j.bbamem.2022.184068] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/06/2022]
Abstract
Membrane proteins reside at interfaces between aqueous and lipid media and solving their molecular structure relies most of the time on removing them from the membrane using detergent. Luckily, this solubilization process does not strip them from all the associated lipids and single-particle cryo-transmission electron microscopy (SP-TEM) has proved a very good tool to visualise both protein high-resolution structure and, often, many of its associated lipids. In this review, we observe membrane protein structures from the Protein DataBank and their associated maps in the Electron Microscopy DataBase and determine how the SP-TEM maps allow lipid visualization, the type of binding sites, the influence of symmetry, resolution and other factors. We illustrate lipid visualization around and inside the protein core, show that some lipid bilayers in the core can be shifted with respect to the membrane and how some proteins can actively bend the lipid bilayer that binds to them. We conclude that resolution improvement in SP-TEM will likely enable many more discoveries regarding the role of lipids bound to proteins.
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Affiliation(s)
- Valérie Biou
- Université de Paris, CNRS, Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, UMR 7099, Institut de Biologie Physico-Chimique, F-75005 Paris, France.
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Chetri S. The culmination of multidrug-resistant efflux pumps vs. meager antibiotic arsenal era: Urgent need for an improved new generation of EPIs. Front Microbiol 2023; 14:1149418. [PMID: 37138605 PMCID: PMC10149990 DOI: 10.3389/fmicb.2023.1149418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/13/2023] [Indexed: 05/05/2023] Open
Abstract
Efflux pumps function as an advanced defense system against antimicrobials by reducing the concentration of drugs inside the bacteria and extruding the substances outside. Various extraneous substances, including antimicrobials, toxic heavy metals, dyes, and detergents, have been removed by this protective barrier composed of diverse transporter proteins found in between the cell membrane and the periplasm within the bacterial cell. In this review, multiple efflux pump families have been analytically and widely outlined, and their potential applications have been discussed in detail. Additionally, this review also discusses a variety of biological functions of efflux pumps, including their role in the formation of biofilms, quorum sensing, their survivability, and the virulence in bacteria, and the genes/proteins associated with efflux pumps have also been explored for their potential relevance to antimicrobial resistance and antibiotic residue detection. A final discussion centers around efflux pump inhibitors, particularly those derived from plants.
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Radi MS, Munro LJ, Salcedo-Sora JE, Kim SH, Feist AM, Kell DB. Understanding Functional Redundancy and Promiscuity of Multidrug Transporters in E. coli under Lipophilic Cation Stress. MEMBRANES 2022; 12:1264. [PMID: 36557171 PMCID: PMC9783932 DOI: 10.3390/membranes12121264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/27/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Multidrug transporters (MDTs) are major contributors to microbial drug resistance and are further utilized for improving host phenotypes in biotechnological applications. Therefore, the identification of these MDTs and the understanding of their mechanisms of action in vivo are of great importance. However, their promiscuity and functional redundancy represent a major challenge towards their identification. Here, a multistep tolerance adaptive laboratory evolution (TALE) approach was leveraged to achieve this goal. Specifically, a wild-type E. coli K-12-MG1655 and its cognate knockout individual mutants ΔemrE, ΔtolC, and ΔacrB were evolved separately under increasing concentrations of two lipophilic cations, tetraphenylphosphonium (TPP+), and methyltriphenylphosphonium (MTPP+). The evolved strains showed a significant increase in MIC values of both cations and an apparent cross-cation resistance. Sequencing of all evolved mutants highlighted diverse mutational mechanisms that affect the activity of nine MDTs including acrB, mdtK, mdfA, acrE, emrD, tolC, acrA, mdtL, and mdtP. Besides regulatory mutations, several structural mutations were recognized in the proximal binding domain of acrB and the permeation pathways of both mdtK and mdfA. These details can aid in the rational design of MDT inhibitors to efficiently combat efflux-based drug resistance. Additionally, the TALE approach can be scaled to different microbes and molecules of medical and biotechnological relevance.
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Affiliation(s)
- Mohammad S. Radi
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kongens Lyngby, Denmark
| | - Lachlan J. Munro
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kongens Lyngby, Denmark
| | - Jesus E. Salcedo-Sora
- GeneMill, Shared Research Facilities, Faculty of Health and Life Sciences, University of Liverpool, Crown St., Liverpool L69 7ZB, UK
| | - Se Hyeuk Kim
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kongens Lyngby, Denmark
| | - Adam M. Feist
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kongens Lyngby, Denmark
- Department of Bioengineering, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Douglas B. Kell
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Building 220, Kemitorvet, 2800 Kongens Lyngby, Denmark
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Crown St., Liverpool L69 7ZB, UK
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