1
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Langelier C, Lu D, Kalantar K, Chu V, Glascock A, Guerrero E, Bernick N, Butcher X, Ewing K, Fahsbender E, Holmes O, Hoops E, Jones A, Lim R, McCanny S, Reynoso L, Rosario K, Tang J, Valenzuela O, Mourani P, Pickering A, Raphenya A, Alcock B, McArthur A. Simultaneous detection of pathogens and antimicrobial resistance genes with the open source, cloud-based, CZ ID pipeline. RESEARCH SQUARE 2024:rs.3.rs-4271356. [PMID: 38746293 PMCID: PMC11092797 DOI: 10.21203/rs.3.rs-4271356/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Antimicrobial resistant (AMR) pathogens represent urgent threats to human health, and their surveillance is of paramount importance. Metagenomic next generation sequencing (mNGS) has revolutionized such efforts, but remains challenging due to the lack of open-access bioinformatics tools capable of simultaneously analyzing both microbial and AMR gene sequences. To address this need, we developed the CZ ID AMR module, an open-access, cloud-based workflow designed to integrate detection of both microbes and AMR genes in mNGS and whole-genome sequencing (WGS) data. It leverages the Comprehensive Antibiotic Resistance Database and associated Resistance Gene Identifier software, and works synergistically with the CZ ID short-read mNGS module to enable broad detection of both microbes and AMR genes. We highlight diverse applications of the AMR module through analysis of both publicly available and newly generated mNGS and WGS data from four clinical cohort studies and an environmental surveillance project. Through genomic investigations of bacterial sepsis and pneumonia cases, hospital outbreaks, and wastewater surveillance data, we gain a deeper understanding of infectious agents and their resistomes, highlighting the value of integrating microbial identification and AMR profiling for both research and public health. We leverage additional functionalities of the CZ ID mNGS platform to couple resistome profiling with the assessment of phylogenetic relationships between nosocomial pathogens, and further demonstrate the potential to capture the longitudinal dynamics of pathogen and AMR genes in hospital acquired bacterial infections. In sum, the new AMR module advances the capabilities of the open-access CZ ID microbial bioinformatics platform by integrating pathogen detection and AMR profiling from mNGS and WGS data. Its development represents a critical step toward democratizing pathogen genomic analysis and supporting collaborative efforts to combat the growing threat of AMR.
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Affiliation(s)
| | - Dan Lu
- Chan Zuckerberg Initiative
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2
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Lu D, Kalantar KL, Chu VT, Glascock AL, Guerrero ES, Bernick N, Butcher X, Ewing K, Fahsbender E, Holmes O, Hoops E, Jones AE, Lim R, McCanny S, Reynoso L, Rosario K, Tang J, Valenzuela O, Mourani PM, Pickering AJ, Raphenya AR, Alcock BP, McArthur AG, Langelier CR. Simultaneous detection of pathogens and antimicrobial resistance genes with the open source, cloud-based, CZ ID pipeline. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589250. [PMID: 38645206 PMCID: PMC11030322 DOI: 10.1101/2024.04.12.589250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Antimicrobial resistant (AMR) pathogens represent urgent threats to human health, and their surveillance is of paramount importance. Metagenomic next generation sequencing (mNGS) has revolutionized such efforts, but remains challenging due to the lack of open-access bioinformatics tools capable of simultaneously analyzing both microbial and AMR gene sequences. To address this need, we developed the Chan Zuckerberg ID (CZ ID) AMR module, an open-access, cloud-based workflow designed to integrate detection of both microbes and AMR genes in mNGS and whole-genome sequencing (WGS) data. It leverages the Comprehensive Antibiotic Resistance Database and associated Resistance Gene Identifier software, and works synergistically with the CZ ID short-read mNGS module to enable broad detection of both microbes and AMR genes. We highlight diverse applications of the AMR module through analysis of both publicly available and newly generated mNGS and WGS data from four clinical cohort studies and an environmental surveillance project. Through genomic investigations of bacterial sepsis and pneumonia cases, hospital outbreaks, and wastewater surveillance data, we gain a deeper understanding of infectious agents and their resistomes, highlighting the value of integrating microbial identification and AMR profiling for both research and public health. We leverage additional functionalities of the CZ ID mNGS platform to couple resistome profiling with the assessment of phylogenetic relationships between nosocomial pathogens, and further demonstrate the potential to capture the longitudinal dynamics of pathogen and AMR genes in hospital acquired bacterial infections. In sum, the new AMR module advances the capabilities of the open-access CZ ID microbial bioinformatics platform by integrating pathogen detection and AMR profiling from mNGS and WGS data. Its development represents a critical step toward democratizing pathogen genomic analysis and supporting collaborative efforts to combat the growing threat of AMR.
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Affiliation(s)
- Dan Lu
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | | | - Victoria T. Chu
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Division of Infectious Diseases, University of California, San Francisco, San Francisco, CA, USA
| | | | | | - Nina Bernick
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | | | - Kirsty Ewing
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | | | | | - Erin Hoops
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | - Ann E. Jones
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | - Ryan Lim
- Chan Zuckerberg Initiative, Redwood City, CA, USA
| | | | | | | | | | | | - Peter M. Mourani
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Arkansas Children’s, Little Rock, AR, USA
| | - Amy J. Pickering
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- University of California, Berkeley, Berkeley, CA, USA
| | - Amogelang R. Raphenya
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Brian P. Alcock
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Andrew G. McArthur
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Charles R. Langelier
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Division of Infectious Diseases, University of California, San Francisco, San Francisco, CA, USA
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3
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Nithiya P, Alagarsamy G, Sathish PB, Rajarathnam D, Li X, Jeyaraj S, Satheesh M, Selvakumar R. Impact of effluent parameters and vancomycin concentration on vancomycin resistant Escherichia coli and its host specific bacteriophage lytic activity in hospital effluent. ENVIRONMENTAL RESEARCH 2024; 247:118334. [PMID: 38316381 DOI: 10.1016/j.envres.2024.118334] [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: 05/11/2023] [Revised: 01/26/2024] [Accepted: 01/27/2024] [Indexed: 02/07/2024]
Abstract
Vancomycin resistance in bacteria has been classified under high priority category by World Health Organization (WHO) and its presence in hospital effluent is reported to be increasing owing to excess antibiotics use. Among various strategies, bacteriophage has been recently considered as a promising biological agent for combating such antimicrobial resistant bacteria (ARB). However, the influence of effluent's properties on phage-ARB interaction in actual hospital effluent is not completely understood. The present works intends to study this influence of hospital effluent and its parameters on the interaction between vancomycin resistant E. coli (VRE) and its host specific bacteriophage. The isolated VRE was identified by 16S rRNA sequencing, matrix-assisted laser desorption/ionization-time of flight (MALDI - TOF) and whole genome sequencing. The infectivity of phage onto host bacteria was investigated using electron microscopic techniques, dynamic light scattering (DLS), spectrofluorophotometer and confirmed using double agar overlay method. The monovalency and polyvalency of isolated phage against various bacterial species were determined. The phage morphology was identical to T7 phage belonging to Podoviridae. The phage lysis was maximum at pH 7 (90.2%), 37 °C (91.6%) and vancomycin concentration of 50 μg/mL in both synthetic media (89.13%) and effluent (100%). At a maximum vancomycin concentration of 100 μg/mL, decrease in Ca, K, Mg and P (up to 19.70, 14.18, 28, and 15.82% respectively) concentration in effluent was observed due to phage infectivity when compared to control. The whole genome sequencing was performed and the bioinformatics analysis presented the role of mdfA gene encoding the efflux pump in causing vancomycin resistance in E. coli. It also depicted the presence of multiple genes responsible for mercury, cobalt, zinc and cadmium resistance in VRE. These results clearly indicate that bacteriophage mediated combating of VRE is possible in actual hospital effluent and can be used as one of the treatment methods.
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Affiliation(s)
- P Nithiya
- Department of Nanobiotechnology, PSG Institute of Advanced Studies, Coimbatore, 641004, India
| | - G Alagarsamy
- Department of Nanobiotechnology, PSG Institute of Advanced Studies, Coimbatore, 641004, India
| | - P B Sathish
- Department of Nanobiotechnology, PSG Institute of Advanced Studies, Coimbatore, 641004, India
| | - D Rajarathnam
- Australian Centre for Water and Environmental Biotechnology, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia
| | - Xu Li
- Department of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Sankarganesh Jeyaraj
- PSG Center for Molecular Medicine and Therapeutics, PSG Institute of Medical Sciences and Research, Coimbatore, 641004, India; PSG Center for Genetics and Molecular Biology, Off Avinashi Road, Coimbatore, 641004, India
| | - Manjima Satheesh
- PSG Center for Molecular Medicine and Therapeutics, PSG Institute of Medical Sciences and Research, Coimbatore, 641004, India; PSG Center for Genetics and Molecular Biology, Off Avinashi Road, Coimbatore, 641004, India
| | - R Selvakumar
- Department of Nanobiotechnology, PSG Institute of Advanced Studies, Coimbatore, 641004, India.
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4
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Drew D, Boudker O. Ion and lipid orchestration of secondary active transport. Nature 2024; 626:963-974. [PMID: 38418916 DOI: 10.1038/s41586-024-07062-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 01/12/2024] [Indexed: 03/02/2024]
Abstract
Transporting small molecules across cell membranes is an essential process in cell physiology. Many structurally diverse, secondary active transporters harness transmembrane electrochemical gradients of ions to power the uptake or efflux of nutrients, signalling molecules, drugs and other ions across cell membranes. Transporters reside in lipid bilayers on the interface between two aqueous compartments, where they are energized and regulated by symported, antiported and allosteric ions on both sides of the membrane and the membrane bilayer itself. Here we outline the mechanisms by which transporters couple ion and solute fluxes and discuss how structural and mechanistic variations enable them to meet specific physiological needs and adapt to environmental conditions. We then consider how general bilayer properties and specific lipid binding modulate transporter activity. Together, ion gradients and lipid properties ensure the effective transport, regulation and distribution of small molecules across cell membranes.
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Affiliation(s)
- David Drew
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
| | - Olga Boudker
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA.
- Howard Hughes Medical Institute, Weill Cornell Medicine, New York, NY, USA.
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Antibiotic resistance genes, mobile elements, virulence genes, and phages in cultivated ESBL-producing Escherichia coli of poultry origin in Kwara State, North Central Nigeria. Int J Food Microbiol 2023; 389:110086. [PMID: 36738714 DOI: 10.1016/j.ijfoodmicro.2023.110086] [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] [Received: 08/31/2022] [Revised: 01/03/2023] [Accepted: 01/07/2023] [Indexed: 01/22/2023]
Abstract
The paucity of information on the genomic diversity of drug-resistant bacteria in most food-producing animals, including poultry in Nigeria, has led to poor hazard characterization and the lack of critical control points to safeguard public health. Hence, this study used whole genome sequencing (WGS) to assess the presence and the diversity of antibiotic resistance genes, mobile genetic elements, virulence genes, and phages in Extended Spectrum Beta Lactamase producing Escherichia coli (ESBL - E. coli) isolates obtained from poultry via the EURL guideline of 2017 in Ilorin, Nigeria. The prevalence of ESBL - E. coli in poultry was 10.5 % (n = 37/354). The phenotypic antibiotic susceptibility testing showed that all the ESBL- E. coli isolates were multi-drug resistant (MDR). The in-silico analysis of the WGS raw-read data from 11 purposively selected isolates showed that the isolates had a wide array of ARGs that conferred resistance to beta-lactam antibiotics, and 8 other classes of antibiotics (fluoroquinolones, foliate pathway antagonists, aminoglycoside, phenicol, tetracycline, epoxide, macrolides, and rifamycin). All the ARGs were in the bacterial chromosome except in two isolates where plasmid-mediated quinolone resistance (PMQR) was detected. Two isolates carried the gyrAp.S83L mutation which confers resistance to certain fluoroquinolones. The mobilome consisted of several Col-plasmids and the predominant IncF plasmids belonged to the IncF64:A-:B27 sequence type. The virulome consisted of genes that function as adhesins, iron acquisition genes, toxins, and protectins. Intact phages were found in 8 of the 11 isolates and the phageome consisted of representatives of four families of viruses: Myoviridae (62.5 %, n = 5/8), Siphoviridae (37.5 %, n = 3/8), Inoviridae (12.5 %, n = 1), and Podoviridae (12.5 %, n = 1/8). ESBL - E. coli isolates harboured 1-5 intact phages and no ARGs were identified on any of the phages. Although five of the isolates belonged to phylogroup A, the isolates were diverse as they belonged to different serotype and sequence types. Our findings demonstrate the high genomic diversity of ESBL - E. coli of poultry origin in Ilorin, Nigeria. These diverse isolates harbor clinically relevant ARGs, mobile elements, virulence genes, and phages that may have detrimental zoonotic potentials on human health.
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Hickman RA, Agarwal V, Sjöström K, Emanuelson U, Fall N, Sternberg-Lewerin S, Järhult JD. Dissemination of Resistant Escherichia coli Among Wild Birds, Rodents, Flies, and Calves on Dairy Farms. Front Microbiol 2022; 13:838339. [PMID: 35432261 PMCID: PMC9010975 DOI: 10.3389/fmicb.2022.838339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
Abstract
Antimicrobial resistance (AMR) in bacteria in the livestock is a growing problem, partly due to inappropriate use of antimicrobial drugs. Antimicrobial use (AMU) occurs in Swedish dairy farming but is restricted to the treatment of sick animals based on prescription by a veterinary practitioner. Despite these strict rules, calves shedding antimicrobial resistant Enterobacteriaceae have been recorded both in dairy farms and in slaughterhouses. Yet, not much is known how these bacteria disseminate into the local environment around dairy farms. In this study, we collected samples from four animal sources (fecal samples from calves, birds and rodents, and whole flies) and two environmental sources (cow manure drains and manure pits). From the samples, Escherichia coli was isolated and antimicrobial susceptibility testing performed. A subset of isolates was whole genome sequenced to evaluate relatedness between sources and genomic determinants such as antimicrobial resistance genes (ARGs) and the presence of plasmids were assessed. We detected both ARGs, mobile genetic elements and low rates of AMR. In particular, we observed four potential instances of bacterial clonal sharing in two different animal sources. This demonstrates resistant E. coli dissemination potential within the dairy farm, between calves and scavenger animals (rodents and flies). AMR dissemination and the zoonotic AMR risk is generally low in countries with low and restricted AMU. However, we show that interspecies dissemination does occur, and in countries that have little to no AMU restrictions this risk could be under-estimated.
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Affiliation(s)
- Rachel A. Hickman
- Department of Medical Sciences, Zoonosis Science Center, Uppsala University, Uppsala, Sweden
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Uppsala, Sweden
- *Correspondence: Rachel A. Hickman,
| | - Viktoria Agarwal
- Department of Medical Biochemistry and Microbiology, Zoonosis Science Center, Uppsala University, Uppsala, Sweden
- Institute of Environmental Engineering, Zürich, Switzerland
| | - Karin Sjöström
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Ulf Emanuelson
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Nils Fall
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Susanna Sternberg-Lewerin
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Josef D. Järhult
- Department of Medical Sciences, Zoonosis Science Center, Uppsala University, Uppsala, Sweden
- *Correspondence: Rachel A. Hickman,
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7
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Patel H, Wu ZX, Chen Y, Bo L, Chen ZS. Drug resistance: from bacteria to cancer. MOLECULAR BIOMEDICINE 2021; 2:27. [PMID: 35006446 PMCID: PMC8607383 DOI: 10.1186/s43556-021-00041-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Accepted: 04/22/2021] [Indexed: 12/14/2022] Open
Abstract
The phenomenon of drug resistance has been a hindrance to therapeutic medicine since the late 1940s. There is a plethora of factors and mechanisms contributing to progression of drug resistance. From prokaryotes to complex cancers, drug resistance is a prevailing issue in clinical medicine. Although there are numerous factors causing and influencing the phenomenon of drug resistance, cellular transporters contribute to a noticeable majority. Efflux transporters form a huge family of proteins and are found in a vast number of species spanning from prokaryotes to complex organisms such as humans. During the last couple of decades, various approaches in analyses of biochemistry and pharmacology of transporters have led us to understand much more about drug resistance. In this review, we have discussed the structure, function, potential causes, and mechanisms of multidrug resistance in bacteria as well as cancers.
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Affiliation(s)
- Harsh Patel
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA
| | - Zhuo-Xun Wu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA
| | - Yanglu Chen
- Columbia University Vagelos College of Physicians and Surgeons, New York, NY, 10032, USA
| | - Letao Bo
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA
| | - Zhe-Sheng Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, Queens, New York, NY, 11439, USA.
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8
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Mukhtar I, Iftikhar A, Imran M, Ijaz MU, Irfan S, Anwar H. The Competitive Absorption by the Gut Microbiome Suggests the First-Order Absorption Kinetics of Caffeine. Dose Response 2021; 19:15593258211033111. [PMID: 34421438 PMCID: PMC8375357 DOI: 10.1177/15593258211033111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022] Open
Abstract
In the literature archive, the intestinal microbiome is now considered as a discrete organ system. Despite living symbiotically with the human body, the gut microbiome is represented as potential drug targets because of its ability to modify the pharmacokinetics of orally administered drugs. Structural biology analysis indicates the existence of homology between transport proteins of microbial cells and membranes of enterocytes. It is speculated that structural similarity in the protein transporters may provoke an unwanted phenomenon of drug uptake by the gut microbiome present in the small intestine of the host. Considering this hypothesis, we analyzed the absorbance of orally administered caffeine by the gut microbiota in in vivo albino rat model through the RP-HPLC-UV approach. Microbiome absorbed the caffeine maximally at 2 hours and minimally at 5 hours post-drug administration following first-order absorption kinetics in a nonlinear way. Drug absorbance of microbial pellet and percent dose recovery was found significantly higher (P ≤ .05) at 2 hours post-administration as compared to all other groups. As speculated, our findings advocated the phenomenon that the gut microbiome influences the absorption of caffeine molecules. Members of the gut microbiome exhibited grouped behavior following first-order absorption kinetics in a nonlinear pattern.
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Affiliation(s)
- Imran Mukhtar
- Department of Physiology, Government College University, Faisalabad, Pakistan.,Sir Sadiq Muhammad Khan Abbasi Post Graduate Medical College, Faculty of Medicine and Allied Health Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Arslan Iftikhar
- Department of Physiology, Government College University, Faisalabad, Pakistan
| | - Muhammad Imran
- Department of Food Science, Government College University, Faisalabad, Pakistan
| | - Muhammad Umar Ijaz
- Department of Zoology, Wildlife and Fisheries, University of Agriculture, Faisalabad, Pakistan
| | - Shahzad Irfan
- Department of Physiology, Government College University, Faisalabad, Pakistan
| | - Haseeb Anwar
- Department of Physiology, Government College University, Faisalabad, Pakistan
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9
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Drew D, North RA, Nagarathinam K, Tanabe M. Structures and General Transport Mechanisms by the Major Facilitator Superfamily (MFS). Chem Rev 2021; 121:5289-5335. [PMID: 33886296 PMCID: PMC8154325 DOI: 10.1021/acs.chemrev.0c00983] [Citation(s) in RCA: 157] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Indexed: 12/12/2022]
Abstract
The major facilitator superfamily (MFS) is the largest known superfamily of secondary active transporters. MFS transporters are responsible for transporting a broad spectrum of substrates, either down their concentration gradient or uphill using the energy stored in the electrochemical gradients. Over the last 10 years, more than a hundred different MFS transporter structures covering close to 40 members have provided an atomic framework for piecing together the molecular basis of their transport cycles. Here, we summarize the remarkable promiscuity of MFS members in terms of substrate recognition and proton coupling as well as the intricate gating mechanisms undergone in achieving substrate translocation. We outline studies that show how residues far from the substrate binding site can be just as important for fine-tuning substrate recognition and specificity as those residues directly coordinating the substrate, and how a number of MFS transporters have evolved to form unique complexes with chaperone and signaling functions. Through a deeper mechanistic description of glucose (GLUT) transporters and multidrug resistance (MDR) antiporters, we outline novel refinements to the rocker-switch alternating-access model, such as a latch mechanism for proton-coupled monosaccharide transport. We emphasize that a full understanding of transport requires an elucidation of MFS transporter dynamics, energy landscapes, and the determination of how rate transitions are modulated by lipids.
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Affiliation(s)
- David Drew
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Rachel A. North
- Department
of Biochemistry and Biophysics, Stockholm
University, SE 106 91 Stockholm, Sweden
| | - Kumar Nagarathinam
- Center
of Structural and Cell Biology in Medicine, Institute of Biochemistry, University of Lübeck, D-23538, Lübeck, Germany
| | - Mikio Tanabe
- Structural
Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Oho 1-1, Tsukuba, Ibaraki 305-0801, Japan
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10
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Kell DB. A protet-based, protonic charge transfer model of energy coupling in oxidative and photosynthetic phosphorylation. Adv Microb Physiol 2021; 78:1-177. [PMID: 34147184 DOI: 10.1016/bs.ampbs.2021.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Textbooks of biochemistry will explain that the otherwise endergonic reactions of ATP synthesis can be driven by the exergonic reactions of respiratory electron transport, and that these two half-reactions are catalyzed by protein complexes embedded in the same, closed membrane. These views are correct. The textbooks also state that, according to the chemiosmotic coupling hypothesis, a (or the) kinetically and thermodynamically competent intermediate linking the two half-reactions is the electrochemical difference of protons that is in equilibrium with that between the two bulk phases that the coupling membrane serves to separate. This gradient consists of a membrane potential term Δψ and a pH gradient term ΔpH, and is known colloquially as the protonmotive force or pmf. Artificial imposition of a pmf can drive phosphorylation, but only if the pmf exceeds some 150-170mV; to achieve in vivo rates the imposed pmf must reach 200mV. The key question then is 'does the pmf generated by electron transport exceed 200mV, or even 170mV?' The possibly surprising answer, from a great many kinds of experiment and sources of evidence, including direct measurements with microelectrodes, indicates it that it does not. Observable pH changes driven by electron transport are real, and they control various processes; however, compensating ion movements restrict the Δψ component to low values. A protet-based model, that I outline here, can account for all the necessary observations, including all of those inconsistent with chemiosmotic coupling, and provides for a variety of testable hypotheses by which it might be refined.
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Affiliation(s)
- Douglas B Kell
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative, Biology, University of Liverpool, Liverpool, United Kingdom; The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Lyngby, Denmark.
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11
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Henderson PJF, Maher C, Elbourne LDH, Eijkelkamp BA, Paulsen IT, Hassan KA. Physiological Functions of Bacterial "Multidrug" Efflux Pumps. Chem Rev 2021; 121:5417-5478. [PMID: 33761243 DOI: 10.1021/acs.chemrev.0c01226] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial multidrug efflux pumps have come to prominence in human and veterinary pathogenesis because they help bacteria protect themselves against the antimicrobials used to overcome their infections. However, it is increasingly realized that many, probably most, such pumps have physiological roles that are distinct from protection of bacteria against antimicrobials administered by humans. Here we undertake a broad survey of the proteins involved, allied to detailed examples of their evolution, energetics, structures, chemical recognition, and molecular mechanisms, together with the experimental strategies that enable rapid and economical progress in understanding their true physiological roles. Once these roles are established, the knowledge can be harnessed to design more effective drugs, improve existing microbial production of drugs for clinical practice and of feedstocks for commercial exploitation, and even develop more sustainable biological processes that avoid, for example, utilization of petroleum.
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Affiliation(s)
- Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Claire Maher
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia
| | - Liam D H Elbourne
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park 5042, South Australia, Australia
| | - Ian T Paulsen
- Department of Biomolecular Sciences, Macquarie University, Sydney 2109, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
| | - Karl A Hassan
- School of Environmental and Life Sciences, University of Newcastle, Callaghan 2308, New South Wales, Australia.,ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney 2019, New South Wales, Australia
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12
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Genetic but No Phenotypic Associations between Biocide Tolerance and Antibiotic Resistance in Escherichia coli from German Broiler Fattening Farms. Microorganisms 2021; 9:microorganisms9030651. [PMID: 33801066 PMCID: PMC8003927 DOI: 10.3390/microorganisms9030651] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/18/2021] [Accepted: 03/19/2021] [Indexed: 12/18/2022] Open
Abstract
Biocides are frequently applied as disinfectants in animal husbandry to prevent the transmission of drug-resistant bacteria and to control zoonotic diseases. Concerns have been raised, that their use may contribute to the selection and persistence of antimicrobial-resistant bacteria. Especially, extended-spectrum β-lactamase- and AmpC β-lactamase-producing Escherichia coli have become a global health threat. In our study, 29 ESBL-/AmpC-producing and 64 NON-ESBL-/AmpC-producing E.coli isolates from three German broiler fattening farms collected in 2016 following regular cleaning and disinfection were phylogenetically characterized by whole genome sequencing, analyzed for phylogenetic distribution of virulence-associated genes, and screened for determinants of and associations between biocide tolerance and antibiotic resistance. Of the 30 known and two unknown sequence types detected, ST117 and ST297 were the most common genotypes. These STs are recognized worldwide as pandemic lineages causing disease in humans and poultry. Virulence determinants associated with extraintestinal pathogenic E.coli showed variable phylogenetic distribution patterns. Isolates with reduced biocide susceptibility were rarely found on the tested farms. Nine isolates displayed elevated MICs and/or MBCs of formaldehyde, chlorocresol, peroxyacetic acid, or benzalkonium chloride. Antibiotic resistance to ampicillin, trimethoprim, and sulfamethoxazole was most prevalent. The majority of ESBL-/AmpC-producing isolates carried blaCTX-M (55%) or blaCMY-2 (24%) genes. Phenotypic biocide tolerance and antibiotic resistance were not interlinked. However, biocide and metal resistance determinants were found on mobile genetic elements together with antibiotic resistance genes raising concerns that biocides used in the food industry may lead to selection pressure for strains carrying acquired resistance determinants to different antimicrobials.
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13
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Murakami S, Okada U, van Veen HW. Tripartite transporters as mechanotransmitters in periplasmic alternating-access mechanisms. FEBS Lett 2020; 594:3908-3919. [PMID: 32936941 DOI: 10.1002/1873-3468.13929] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/18/2022]
Abstract
To remove xenobiotics from the periplasmic space, Gram-negative bacteria utilise unique tripartite efflux systems in which a molecular engine in the plasma membrane connects to periplasmic and outer membrane subunits. Substrates bind to periplasmic sections of the engine or sometimes to the periplasmic subunits. Then, the tripartite machines undergo conformational changes that allow the movement of the substrates down the substrate translocation pathway to the outside of the cell. The transmembrane (TM) domains of the tripartite resistance-nodulation-drug-resistance (RND) transporters drive these conformational changes by converting proton motive force into mechanical motion. Similarly, the TM domains of tripartite ATP-binding cassette (ABC) transporters transmit mechanical movement associated with nucleotide binding and hydrolysis at the nucleotide-binding domains to the relevant subunits in the periplasm. In this way, metabolic energy is coupled to periplasmic alternating-access mechanisms to achieve substrate transport across the outer membrane.
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Affiliation(s)
- Satoshi Murakami
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ui Okada
- Department of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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14
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Saha P, Sikdar S, Krishnamoorthy G, Zgurskaya HI, Rybenkov VV. Drug Permeation against Efflux by Two Transporters. ACS Infect Dis 2020; 6:747-758. [PMID: 32039579 DOI: 10.1021/acsinfecdis.9b00510] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The development of new antibiotics against Gram-negative bacteria is hampered by the powerful protective properties of their cell envelope. This envelope consists of two membranes augmented by efflux transporters, which act in synergy to restrict cellular access to a broad range of chemical compounds. Recently, a kinetic model of this system has been constructed. The model revealed a complex, nonlinear behavior of the system, complete with a bifurcation, and matched very well to experimental uptake data. Here, we expand the model to include multiple transporters and apply it to an experimental analysis of antibiotic accumulation in wild-type and efflux-deficient Escherichia coli. We show that transporters acting across the inner and outer membranes have synergistic effects with each other. In contrast, transporters acting across the same membrane are additive as a rule but can be synergistic under special circumstances owing to a bifurcation controlled by the barrier constant. With respect to ethidium bromide, the inner membrane transporter MdfA was synergistic to the TolC-dependent efflux across the outer membrane. The agreement between the model and drug accumulation was very good across a range of tested drug concentrations and strains. However, antibiotic susceptibilities related only qualitatively to the accumulation of the drugs or predictions of the model and could be fit to the model only if additional assumptions were made about the physiological consequences of prolonged cell exposure to the drugs. Thus, the constructed model correctly predicts transmembrane permeation of various compounds and potentially their intracellular activity.
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Affiliation(s)
- Paramita Saha
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Samapan Sikdar
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Ganesh Krishnamoorthy
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
| | - Valentin V. Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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15
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Structure and mechanism of a redesigned multidrug transporter from the Major Facilitator Superfamily. Sci Rep 2020; 10:3949. [PMID: 32127561 PMCID: PMC7054563 DOI: 10.1038/s41598-020-60332-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/06/2020] [Indexed: 01/07/2023] Open
Abstract
The rapid increase of multidrug resistance poses urgent threats to human health. Multidrug transporters prompt multidrug resistance by exporting different therapeutics across cell membranes, often by utilizing the H+ electrochemical gradient. MdfA from Escherichia coli is a prototypical H+ -dependent multidrug transporter belonging to the Major Facilitator Superfamily. Prior studies revealed unusual flexibility in the coupling between multidrug binding and deprotonation in MdfA, but the mechanistic basis for this flexibility was obscure. Here we report the X-ray structures of a MdfA mutant E26T/D34M/A150E, wherein the multidrug-binding and protonation sites were revamped, separately bound to three different substrates at resolutions up to 2.0 Å. To validate the functional relevance of these structures, we conducted mutational and biochemical studies. Our data elucidated intermediate states during antibiotic recognition and suggested structural changes that accompany the substrate-evoked deprotonation of E26T/D34M/A150E. These findings help to explain the mechanistic flexibility in drug/H+ coupling observed in MdfA and may inspire therapeutic development to preempt efflux-mediated antimicrobial resistance.
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16
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Zeng Q, Liao C, Terhune J, Wang L. Impacts of florfenicol on the microbiota landscape and resistome as revealed by metagenomic analysis. MICROBIOME 2019; 7:155. [PMID: 31818316 PMCID: PMC6902485 DOI: 10.1186/s40168-019-0773-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 12/02/2019] [Indexed: 05/26/2023]
Abstract
BACKGROUND Drug-resistant fish pathogens can cause significant economic loss to fish farmers. Since 2012, florfenicol has become an approved drug for treating both septicemia and columnaris diseases in freshwater fish. Due to the limited drug options available for aquaculture, the impact of the therapeutical florfenicol treatment on the microbiota landscape as well as the resistome present in the aquaculture farm environment needs to be evaluated. RESULTS Time-series metagenomic analyses were conducted to the aquatic microbiota present in the tank-based catfish production systems, in which catfish received standard therapeutic 10-day florfenicol treatment following the federal veterinary regulations. Results showed that the florfenicol treatment shifted the structure of the microbiota and reduced the biodiversity of it by acting as a strong stressor. Planctomycetes, Chloroflexi, and 13 other phyla were susceptible to the florfenicol treatment and their abundance was inhibited by the treatment. In contrast, the abundance of several bacteria belonging to the Proteobacteria, Bacteroidetes, Actinobacteria, and Verrucomicrobia phyla increased. These bacteria with increased abundance either harbor florfenicol-resistant genes (FRGs) or had beneficial mutations. The florfenicol treatment promoted the proliferation of florfenicol-resistant genes. The copy number of phenicol-specific resistance genes as well as multiple classes of antibiotic-resistant genes (ARGs) exhibited strong correlations across different genetic exchange communities (p < 0.05), indicating the horizontal transfer of florfenicol-resistant genes among these bacterial species or genera. Florfenicol treatment also induced mutation-driven resistance. Significant changes in single-nucleotide polymorphism (SNP) allele frequencies were observed in membrane transporters, genes involved in recombination, and in genes with primary functions of a resistance phenotype. CONCLUSIONS The therapeutical level of florfenicol treatment significantly altered the microbiome and resistome present in catfish tanks. Both intra-population and inter-population horizontal ARG transfer was observed, with the intra-population transfer being more common. The oxazolidinone/phenicol-resistant gene optrA was the most prevalent transferred ARG. In addition to horizontal gene transfer, bacteria could also acquire florfenicol resistance by regulating the innate efflux systems via mutations. The observations made by this study are of great importance for guiding the strategic use of florfenicol, thus preventing the formation, persistence, and spreading of florfenicol-resistant bacteria and resistance genes in aquaculture.
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Affiliation(s)
- Qifan Zeng
- Department of Animal Sciences, Auburn University, Auburn, AL, 36830, USA
- Ministry of Education Key Laboratory of Marine Genetics and Breeding, College of Marine Science, Ocean University of China, Qingdao, 266003, Shandong, China
| | - Chao Liao
- Department of Animal Sciences, Auburn University, Auburn, AL, 36830, USA
- Department of Food Science and Technology, University of California Davis, Davis, CA, 95616, USA
| | - Jeffery Terhune
- Department of Fisheries and Allied Aquacultures, 203 Swingle Hall, Auburn University, Auburn, AL, 36849, USA
| | - Luxin Wang
- Department of Animal Sciences, Auburn University, Auburn, AL, 36830, USA.
- Department of Food Science and Technology, University of California Davis, Davis, CA, 95616, USA.
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17
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Wu HH, Symersky J, Lu M. Structure of an engineered multidrug transporter MdfA reveals the molecular basis for substrate recognition. Commun Biol 2019; 2:210. [PMID: 31240248 PMCID: PMC6572762 DOI: 10.1038/s42003-019-0446-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/30/2019] [Indexed: 02/05/2023] Open
Abstract
MdfA is a prototypical H+-coupled multidrug transporter that is characterized by extraordinarily broad substrate specificity. The involvement of specific H-bonds in MdfA-drug interactions and the simplicity of altering the substrate specificity of MdfA contradict the promiscuous nature of multidrug recognition, presenting a baffling conundrum. Here we show the X-ray structures of MdfA variant I239T/G354E in complexes with three electrically different ligands, determined at resolutions up to 2.2 Å. Our structures reveal that I239T/G354E interacts with these compounds differently from MdfA and that I239T/G354E possesses two discrete, non-overlapping substrate-binding sites. Our results shed new light on the molecular design of multidrug-binding and protonation sites and highlight the importance of often-neglected, long-range charge-charge interactions in multidrug recognition. Beyond helping to solve the ostensible conundrum of multidrug recognition, our findings suggest the mechanistic difference between substrate and inhibitor for any H+-dependent multidrug transporter, which may open new vistas on curtailing efflux-mediated multidrug resistance.
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Affiliation(s)
- Hsin-Hui Wu
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
| | - Jindrich Symersky
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
| | - Min Lu
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 USA
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18
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smFRET Probing Reveals Substrate-Dependent Conformational Dynamics of E. coli Multidrug MdfA. Biophys J 2019; 116:2296-2303. [PMID: 31146923 DOI: 10.1016/j.bpj.2019.04.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 11/21/2022] Open
Abstract
Bacterial multidrug-resistance transporters of the major facilitator superfamily are distinguished by their extraordinary ability to bind structurally diverse substrates, thus serving as a highly efficient tool to protect cells from multiple toxic substances present in their environment, including antibiotic drugs. However, details of the dynamic conformational changes of the transport cycle involved remain to be elucidated. Here, we used the single-molecule fluorescence resonance energy transfer technique to investigate the conformational behavior of the Escherichia coli multidrug transporter MdfA under conditions of different substrates, pH, and alkali metal ions. Our data show that different substrates exhibit distinct effects on both the conformational distribution and transition rate between two major conformations. Although the cationic substrate tetraphenylphosphonium favors the outward-facing conformation, it has less effect on the transition rate. In contrast, binding of the electroneutral substrate chloramphenicol tends to stabilize the inward-facing conformation and decreases the transition rate. Therefore, our study supports the notion that the MdfA transporter uses distinct mechanisms to transport electroneutral and cationic substrates.
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19
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Reversing resistance to counter antimicrobial resistance in the World Health Organisation's critical priority of most dangerous pathogens. Biosci Rep 2019; 39:BSR20180474. [PMID: 30910848 PMCID: PMC6465202 DOI: 10.1042/bsr20180474] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/18/2019] [Accepted: 03/22/2019] [Indexed: 02/07/2023] Open
Abstract
The speed at which bacteria develop antimicrobial resistance far outpace drug discovery and development efforts resulting in untreatable infections. The World Health Organisation recently released a list of pathogens in urgent need for the development of new antimicrobials. The organisms that are listed as the most critical priority are all Gram-negative bacteria resistant to the carbapenem class of antibiotics. Carbapenem resistance in these organisms is typified by intrinsic resistance due to the expression of antibiotic efflux pumps and the permeability barrier presented by the outer membrane, as well as by acquired resistance due to the acquisition of enzymes able to degrade β-lactam antibiotics. In this perspective article we argue the case for reversing resistance by targeting these resistance mechanisms – to increase our arsenal of available antibiotics and drastically reduce antibiotic discovery times – as the most effective way to combat antimicrobial resistance in these high priority pathogens.
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20
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Foong WE, Tam HK, Crames JJ, Averhoff B, Pos KM. The chloramphenicol/H+ antiporter CraA of Acinetobacter baumannii AYE reveals a broad substrate specificity. J Antimicrob Chemother 2019; 74:1192-1201. [DOI: 10.1093/jac/dkz024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/23/2018] [Accepted: 01/08/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
- Wuen Ee Foong
- Institute of Biochemistry, Goethe‐University Frankfurt, Max‐von‐Laue‐Str. 9, Frankfurt am Main, Germany
| | - Heng-Keat Tam
- Institute of Biochemistry, Goethe‐University Frankfurt, Max‐von‐Laue‐Str. 9, Frankfurt am Main, Germany
| | - Jan J Crames
- Institute of Biochemistry, Goethe‐University Frankfurt, Max‐von‐Laue‐Str. 9, Frankfurt am Main, Germany
| | - Beate Averhoff
- Department of Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Klaas M Pos
- Institute of Biochemistry, Goethe‐University Frankfurt, Max‐von‐Laue‐Str. 9, Frankfurt am Main, Germany
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21
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Nagarathinam K, Nakada-Nakura Y, Parthier C, Terada T, Juge N, Jaenecke F, Liu K, Hotta Y, Miyaji T, Omote H, Iwata S, Nomura N, Stubbs MT, Tanabe M. Outward open conformation of a Major Facilitator Superfamily multidrug/H + antiporter provides insights into switching mechanism. Nat Commun 2018; 9:4005. [PMID: 30275448 PMCID: PMC6167325 DOI: 10.1038/s41467-018-06306-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 08/13/2018] [Indexed: 12/14/2022] Open
Abstract
Multidrug resistance (MDR) poses a major challenge to medicine. A principle cause of MDR is through active efflux by MDR transporters situated in the bacterial membrane. Here we present the crystal structure of the major facilitator superfamily (MFS) drug/H+ antiporter MdfA from Escherichia coli in an outward open conformation. Comparison with the inward facing (drug binding) state shows that, in addition to the expected change in relative orientations of the N- and C-terminal lobes of the antiporter, the conformation of TM5 is kinked and twisted. In vitro reconstitution experiments demonstrate the importance of selected residues for transport and molecular dynamics simulations are used to gain insights into antiporter switching. With the availability of structures of alternative conformational states, we anticipate that MdfA will serve as a model system for understanding drug efflux in MFS MDR antiporters. The multidrug resistance transporter mediated efflux of antibiotics from the bacterial cytoplasm represents a major challenge to medicine. Here authors solve the X-ray crystallographic structure of the drug/H+ antiporter MdfA from Escherichia coli and shed light on the conformational switching mechanism.
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Affiliation(s)
- Kumar Nagarathinam
- ZIK HALOmem, Kurt-Mothes-Straße 3, D-06120, Halle/Saale, Germany.,Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther Universität Halle-Wittenberg, Kurt-Mothes-Straße 3a, D-06120, Halle/Saale, Germany.,Institute of Virology, Hannover Medical School, Carl-Neuberg-Straße 1, D-30625, Hannover, Germany
| | - Yoshiko Nakada-Nakura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Christoph Parthier
- Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther Universität Halle-Wittenberg, Kurt-Mothes-Straße 3a, D-06120, Halle/Saale, Germany
| | - Tohru Terada
- Agricultural Bioinformatics Research Unit, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Narinobu Juge
- Advanced Science Research Center, Okayama University, 1-1-1 Kita-ku, Tsushima-naka, Okayama, 700-8530, Japan
| | - Frank Jaenecke
- ZIK HALOmem, Kurt-Mothes-Straße 3, D-06120, Halle/Saale, Germany
| | - Kehong Liu
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Yunhon Hotta
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Takaaki Miyaji
- Advanced Science Research Center, Okayama University, 1-1-1 Kita-ku, Tsushima-naka, Okayama, 700-8530, Japan
| | - Hiroshi Omote
- Department of Membrane Biochemistry, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 1-1-1 Kita-ku, Tsushima-naka, Okayama, 700-8530, Japan
| | - So Iwata
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan.,RIKEN, SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Norimichi Nomura
- Department of Cell Biology, Graduate School of Medicine, Kyoto University, Konoe-cho, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Milton T Stubbs
- ZIK HALOmem, Kurt-Mothes-Straße 3, D-06120, Halle/Saale, Germany. .,Institut für Biochemie und Biotechnologie, Charles-Tanford-Proteinzentrum, Martin-Luther Universität Halle-Wittenberg, Kurt-Mothes-Straße 3a, D-06120, Halle/Saale, Germany.
| | - Mikio Tanabe
- ZIK HALOmem, Kurt-Mothes-Straße 3, D-06120, Halle/Saale, Germany. .,Structural Biology Research Center, Institute of Materials Structure Science, KEK/High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.
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22
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Zomot E, Yardeni EH, Vargiu AV, Tam HK, Malloci G, Ramaswamy VK, Perach M, Ruggerone P, Pos KM, Bibi E. A New Critical Conformational Determinant of Multidrug Efflux by an MFS Transporter. J Mol Biol 2018. [PMID: 29530612 DOI: 10.1016/j.jmb.2018.02.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Secondary multidrug (Mdr) transporters utilize ion concentration gradients to actively remove antibiotics and other toxic compounds from cells. The model Mdr transporter MdfA from Escherichia coli exchanges dissimilar drugs for protons. The transporter should open at the cytoplasmic side to enable access of drugs into the Mdr recognition pocket. Here we show that the cytoplasmic rim around the Mdr recognition pocket represents a previously overlooked important regulatory determinant in MdfA. We demonstrate that increasing the positive charge of the electrically asymmetric rim dramatically inhibits MdfA activity and sometimes even leads to influx of planar, positively charged compounds, resulting in drug sensitivity. Our results suggest that unlike the mutants with the electrically modified rim, the membrane-embedded wild-type MdfA exhibits a significant probability of an inward-closed conformation, which is further increased by drug binding. Since MdfA binds drugs from its inward-facing environment, these results are intriguing and raise the possibility that the transporter has a sensitive, drug-induced conformational switch, which favors an inward-closed state.
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Affiliation(s)
- Elia Zomot
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eliane Hadas Yardeni
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Heng-Keat Tam
- Institute of Biochemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Giuliano Malloci
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | | | - Michal Perach
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Paolo Ruggerone
- Department of Physics, University of Cagliari, 09042 Monserrato (CA), Italy
| | - Klaas Martinus Pos
- Institute of Biochemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany
| | - Eitan Bibi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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23
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Ito M, Morino M, Krulwich TA. Mrp Antiporters Have Important Roles in Diverse Bacteria and Archaea. Front Microbiol 2017; 8:2325. [PMID: 29218041 PMCID: PMC5703873 DOI: 10.3389/fmicb.2017.02325] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/10/2017] [Indexed: 11/13/2022] Open
Abstract
Mrp (Multiple resistance and pH) antiporter was identified as a gene complementing an alkaline-sensitive mutant strain of alkaliphilic Bacillus halodurans C-125 in 1990. At that time, there was no example of a multi-subunit type Na+/H+ antiporter comprising six or seven hydrophobic proteins, and it was newly designated as the monovalent cation: proton antiporter-3 (CPA3) family in the classification of transporters. The Mrp antiporter is broadly distributed among bacteria and archaea, not only in alkaliphiles. Generally, all Mrp subunits, mrpA–G, are required for enzymatic activity. Two exceptions are Mrp from the archaea Methanosarcina acetivorans and the eubacteria Natranaerobius thermophilus, which are reported to sustain Na+/H+ antiport activity with the MrpA subunit alone. Two large subunits of the Mrp antiporter, MrpA and MrpD, are homologous to membrane-embedded subunits of the respiratory chain complex I, NuoL, NuoM, and NuoN, and the small subunit MrpC has homology with NuoK. The functions of the Mrp antiporter include sodium tolerance and pH homeostasis in an alkaline environment, nitrogen fixation in Schizolobium meliloti, bile salt tolerance in Bacillus subtilis and Vibrio cholerae, arsenic oxidation in Agrobacterium tumefaciens, pathogenesis in Pseudomonas aeruginosa and Staphylococcus aureus, and the conversion of energy involved in metabolism and hydrogen production in archaea. In addition, some Mrp antiporters transport K+ and Ca2+ instead of Na+, depending on the environmental conditions. Recently, the molecular structure of the respiratory chain complex I has been elucidated by others, and details of the mechanism by which it transports protons are being clarified. Based on this, several hypotheses concerning the substrate transport mechanism in the Mrp antiporter have been proposed. The MrpA and MrpD subunits, which are homologous to the proton transport subunit of complex I, are involved in the transport of protons and their coupling cations. Herein, we outline other recent findings on the Mrp antiporter.
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Affiliation(s)
- Masahiro Ito
- Graduate School of Life Sciences, Toyo University, Gunma, Japan.,Bio-Nano Electronics Research Center, Toyo University, Kawagoe, Japan
| | - Masato Morino
- Graduate School of Life Sciences, Toyo University, Gunma, Japan.,Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Terry A Krulwich
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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24
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Prabhala BK, Aduri NG, Sharma N, Shaheen A, Sharma A, Iqbal M, Hansen PR, Brasen C, Gajhede M, Rahman M, Mirza O. The prototypical proton-coupled oligopeptide transporter YdgR from Escherichia coli facilitates chloramphenicol uptake into bacterial cells. J Biol Chem 2017; 293:1007-1017. [PMID: 29150447 DOI: 10.1074/jbc.m117.805960] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 11/07/2017] [Indexed: 11/06/2022] Open
Abstract
Chloramphenicol (Cam) is a broad-spectrum antibiotic used to combat bacterial infections in humans and animals. Cam export from bacterial cells is one of the mechanisms by which pathogens resist Cam's antibacterial effects, and several different proteins are known to facilitate this process. However, to date no report exists on any specific transport protein that facilitates Cam uptake. The proton-coupled oligopeptide transporter (POT) YdgR from Escherichia coli is a prototypical member of the POT family, functioning in proton-coupled uptake of di- and tripeptides. By following bacterial growth and conducting LC-MS-based assays we show here that YdgR facilitates Cam uptake. Some YdgR variants displaying reduced peptide uptake also exhibited reduced Cam uptake, indicating that peptides and Cam bind YdgR at similar regions. Homology modeling of YdgR, Cam docking, and mutational studies suggested a binding mode that resembles that of Cam binding to the multidrug resistance transporter MdfA. To our knowledge, this is the first report of Cam uptake into bacterial cells mediated by a specific transporter protein. Our findings suggest a specific bacterial transporter for drug uptake that might be targeted to promote greater antibiotic influx to increase cytoplasmic antibiotic concentration for enhanced cytotoxicity.
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Affiliation(s)
- Bala K Prabhala
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Nanda G Aduri
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Neha Sharma
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Aqsa Shaheen
- the Health Biotechnology Divisions, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Arpan Sharma
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Mazhar Iqbal
- the Health Biotechnology Divisions, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Paul R Hansen
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Christoffer Brasen
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Michael Gajhede
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
| | - Moazur Rahman
- the Health Biotechnology Divisions, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Osman Mirza
- From the Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen DK-2100, Denmark and
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25
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Clamping down on drugs: the Escherichia coli multidrug efflux protein MdtM. Res Microbiol 2017; 169:461-467. [PMID: 28962921 DOI: 10.1016/j.resmic.2017.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 11/22/2022]
Abstract
Multidrug resistance is principally a consequence of the active transport of drugs out of the cell by proteins that are integral membrane transporters. In the following review, we present a synthesis of current understanding of the Escherichia coli multidrug resistance transporter, MdtM, a 410 amino acid residue protein that belongs to the large and ubiquitous major facilitator superfamily (MFS).
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26
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Yardeni EH, Zomot E, Bibi E. The fascinating but mysterious mechanistic aspects of multidrug transport by MdfA from Escherichia coli. Res Microbiol 2017; 169:455-460. [PMID: 28951231 DOI: 10.1016/j.resmic.2017.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/24/2017] [Accepted: 09/13/2017] [Indexed: 10/18/2022]
Abstract
MdfA is an interesting member of a large group of secondary multidrug (Mdr) transporters. Through genetic, biochemical and biophysical studies of MdfA, many challenging aspects of the multidrug transport phenomenon have been addressed. This includes its ability to interact with chemically unrelated drugs and how it utilizes energy to drive efflux of compounds that are not only structurally, but also electrically, different. Admittedly, however, despite all efforts and a recent pioneering structural contribution, several important mechanistic issues of the promiscuous capabilities of MdfA still seek better molecular and dynamic understanding.
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Affiliation(s)
- Eliane H Yardeni
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Elia Zomot
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Eitan Bibi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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27
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Westfall DA, Krishnamoorthy G, Wolloscheck D, Sarkar R, Zgurskaya HI, Rybenkov VV. Bifurcation kinetics of drug uptake by Gram-negative bacteria. PLoS One 2017; 12:e0184671. [PMID: 28926596 PMCID: PMC5604995 DOI: 10.1371/journal.pone.0184671] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 08/28/2017] [Indexed: 11/18/2022] Open
Abstract
Cell envelopes of many bacteria consist of two membranes studded with efflux transporters. Such organization protects bacteria from the environment and gives rise to multidrug resistance. We report a kinetic model that accurately describes the permeation properties of this system. The model predicts complex non-linear patterns of drug uptake complete with a bifurcation, which recapitulate the known experimental anomalies. We introduce two kinetic parameters, the efflux and barrier constants, which replace those of Michaelis and Menten for trans-envelope transport. Both compound permeation and efflux display transitions, which delineate regimes of efficient and inefficient efflux. The first transition is related to saturation of the transporter by the compound and the second one behaves as a bifurcation and involves saturation of the outer membrane barrier. The bifurcation was experimentally observed in live bacteria. We further found that active efflux of a drug can be orders of magnitude faster than its diffusion into a cell and that the efficacy of a drug depends both on its transport properties and therapeutic potency. This analysis reveals novel physical principles in the behavior of the cellular envelope, creates a framework for quantification of small molecule permeation into bacteria, and should invigorate structure-activity studies of novel antibiotics.
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Affiliation(s)
- David A. Westfall
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - Ganesh Krishnamoorthy
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - David Wolloscheck
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - Rupa Sarkar
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
| | - Helen I. Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
- * E-mail: (VVR); (HIZ)
| | - Valentin V. Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, Stephenson Parkway, Norman, OK, United States of America
- * E-mail: (VVR); (HIZ)
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28
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Modeling the Overproduction of Ribosomes when Antibacterial Drugs Act on Cells. Biophys J 2017; 110:743-748. [PMID: 26840738 PMCID: PMC4744161 DOI: 10.1016/j.bpj.2015.12.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 12/12/2015] [Accepted: 12/15/2015] [Indexed: 02/04/2023] Open
Abstract
Bacteria that are subjected to ribosome-inhibiting antibiotic drugs show an interesting behavior: Although the drug slows down cell growth, it also paradoxically increases the cell’s concentration of ribosomes. We combine our earlier nonlinear model of the energy-biomass balance in undrugged Escherichia coli cells with Michaelis-Menten binding of drugs that inactivate ribosomes. Predictions are in good agreement with experiments on ribosomal concentrations and synthesis rates versus drug concentrations and growth rates. The model indicates that the added drug drives the cell to overproduce ribosomes, keeping roughly constant the level of ribosomes producing ribosomal proteins, an important quantity for cell growth. The model also predicts that ribosomal production rates should increase and then decrease with added drug. This model gives insights into the driving forces in cells and suggests new experiments.
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29
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Kumar S, Bradley CL, Mukashyaka P, Doerrler WT. Identification of essential arginine residues ofEscherichia coliDedA/Tvp38 family membrane proteins YqjA and YghB. FEMS Microbiol Lett 2016; 363:fnw133. [DOI: 10.1093/femsle/fnw133] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/14/2016] [Indexed: 12/15/2022] Open
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30
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Zhang XC, Zhao Y, Heng J, Jiang D. Energy coupling mechanisms of MFS transporters. Protein Sci 2015; 24:1560-79. [PMID: 26234418 DOI: 10.1002/pro.2759] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/01/2023]
Abstract
Major facilitator superfamily (MFS) is a large class of secondary active transporters widely expressed across all life kingdoms. Although a common 12-transmembrane helix-bundle architecture is found in most MFS crystal structures available, a common mechanism of energy coupling remains to be elucidated. Here, we discuss several models for energy-coupling in the transport process of the transporters, largely based on currently available structures and the results of their biochemical analyses. Special attention is paid to the interaction between protonation and the negative-inside membrane potential. Also, functional roles of the conserved sequence motifs are discussed in the context of the 3D structures. We anticipate that in the near future, a unified picture of the functions of MFS transporters will emerge from the insights gained from studies of the common architectures and conserved motifs.
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Affiliation(s)
- Xuejun C Zhang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101
| | - Yan Zhao
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101
| | - Jie Heng
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101
| | - Daohua Jiang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101
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31
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Heng J, Zhao Y, Liu M, Liu Y, Fan J, Wang X, Zhao Y, Zhang XC. Substrate-bound structure of the E. coli multidrug resistance transporter MdfA. Cell Res 2015; 25:1060-73. [PMID: 26238402 DOI: 10.1038/cr.2015.94] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/02/2015] [Accepted: 05/07/2015] [Indexed: 12/12/2022] Open
Abstract
Multidrug resistance is a serious threat to public health. Proton motive force-driven antiporters from the major facilitator superfamily (MFS) constitute a major group of multidrug-resistance transporters. Currently, no reports on crystal structures of MFS antiporters in complex with their substrates exist. The E. coli MdfA transporter is a well-studied model system for biochemical analyses of multidrug-resistance MFS antiporters. Here, we report three crystal structures of MdfA-ligand complexes at resolutions up to 2.0 Å, all in the inward-facing conformation. The substrate-binding site sits proximal to the conserved acidic residue, D34. Our mutagenesis studies support the structural observations of the substrate-binding mode and the notion that D34 responds to substrate binding by adjusting its protonation status. Taken together, our data unveil the substrate-binding mode of MFS antiporters and suggest a mechanism of transport via this group of transporters.
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Affiliation(s)
- Jie Heng
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Zhao
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.,School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Ming Liu
- College of Biotechnology, Tianjin University of Science and Technology, 29 13th Street, TEDA, Tianjin 300457, China
| | - Yue Liu
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Junping Fan
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Xianping Wang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Yongfang Zhao
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Xuejun C Zhang
- National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
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32
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Escherichia coli YqjA, a Member of the Conserved DedA/Tvp38 Membrane Protein Family, Is a Putative Osmosensing Transporter Required for Growth at Alkaline pH. J Bacteriol 2015; 197:2292-300. [PMID: 25917916 DOI: 10.1128/jb.00175-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 04/22/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The ability to persist and grow under alkaline conditions is an important characteristic of many bacteria. In order to survive at alkaline pH, Escherichia coli must maintain a stable cytoplasmic pH of about 7.6. Membrane cation/proton antiporters play a major role in alkaline pH homeostasis by catalyzing active inward proton transport. The DedA/Tvp38 family is a highly conserved membrane protein family of unknown function present in most sequenced genomes. YqjA and YghB are members of the E. coli DedA family with 62% amino acid identity and partially redundant functions. We have shown that E. coli with ΔyqjA and ΔyghB mutations cannot properly maintain the proton motive force (PMF) and is compromised in PMF-dependent drug efflux and other PMF-dependent functions. Furthermore, the functions of YqjA and YghB are dependent upon membrane-embedded acidic amino acids, a hallmark of several families of proton-dependent transporters. Here, we show that the ΔyqjA mutant (but not ΔyghB) cannot grow under alkaline conditions (ranging from pH 8.5 to 9.5), unlike the parent E. coli. Overexpression of yqjA restores growth at alkaline pH, but only when more than ∼100 mM sodium or potassium is present in the growth medium. Increasing the osmotic pressure by the addition of sucrose enhances the ability of YqjA to support growth under alkaline conditions in the presence of low salt concentrations, consistent with YqjA functioning as an osmosensor. We suggest that YqjA possesses proton-dependent transport activity that is stimulated by osmolarity and that it plays a significant role in the survival of E. coli at alkaline pH. IMPORTANCE The ability to survive under alkaline conditions is important for many species of bacteria. Escherichia coli can grow at pH 5.5 to 9.5 while maintaining a constant cytoplasmic pH of about 7.6. Under alkaline conditions, bacteria rely upon proton-dependent transporters to maintain a constant cytoplasmic pH. The DedA/Tvp38 protein family is a highly conserved but poorly characterized family of membrane proteins. Here, we show that the DedA/Tvp38 protein YqjA is critical for E. coli to survive at pH 8.5 to 9.5. YqjA requires sodium and potassium for this function. At low cation concentrations, osmolytes, including sucrose, can facilitate rescue of E. coli growth by YqjA at high pH. These data are consistent with YqjA functioning as an osmosensing cation-dependent proton transporter.
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33
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Li XZ, Plésiat P, Nikaido H. The challenge of efflux-mediated antibiotic resistance in Gram-negative bacteria. Clin Microbiol Rev 2015; 28:337-418. [PMID: 25788514 PMCID: PMC4402952 DOI: 10.1128/cmr.00117-14] [Citation(s) in RCA: 899] [Impact Index Per Article: 99.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The global emergence of multidrug-resistant Gram-negative bacteria is a growing threat to antibiotic therapy. The chromosomally encoded drug efflux mechanisms that are ubiquitous in these bacteria greatly contribute to antibiotic resistance and present a major challenge for antibiotic development. Multidrug pumps, particularly those represented by the clinically relevant AcrAB-TolC and Mex pumps of the resistance-nodulation-division (RND) superfamily, not only mediate intrinsic and acquired multidrug resistance (MDR) but also are involved in other functions, including the bacterial stress response and pathogenicity. Additionally, efflux pumps interact synergistically with other resistance mechanisms (e.g., with the outer membrane permeability barrier) to increase resistance levels. Since the discovery of RND pumps in the early 1990s, remarkable scientific and technological advances have allowed for an in-depth understanding of the structural and biochemical basis, substrate profiles, molecular regulation, and inhibition of MDR pumps. However, the development of clinically useful efflux pump inhibitors and/or new antibiotics that can bypass pump effects continues to be a challenge. Plasmid-borne efflux pump genes (including those for RND pumps) have increasingly been identified. This article highlights the recent progress obtained for organisms of clinical significance, together with methodological considerations for the characterization of MDR pumps.
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Affiliation(s)
- Xian-Zhi Li
- Human Safety Division, Veterinary Drugs Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Patrick Plésiat
- Laboratoire de Bactériologie, Faculté de Médecine-Pharmacie, Centre Hospitalier Régional Universitaire, Université de Franche-Comté, Besançon, France
| | - Hiroshi Nikaido
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
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34
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Purification of a Multidrug Resistance Transporter for Crystallization Studies. Antibiotics (Basel) 2015; 4:113-35. [PMID: 27025617 PMCID: PMC4790320 DOI: 10.3390/antibiotics4010113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 02/23/2015] [Accepted: 02/25/2015] [Indexed: 01/12/2023] Open
Abstract
Crystallization of integral membrane proteins is a challenging field and much effort has been invested in optimizing the overexpression and purification steps needed to obtain milligram amounts of pure, stable, monodisperse protein sample for crystallography studies. Our current work involves the structural and functional characterization of the Escherichia coli multidrug resistance transporter MdtM, a member of the major facilitator superfamily (MFS). Here we present a protocol for isolation of MdtM to increase yields of recombinant protein to the milligram quantities necessary for pursuit of structural studies using X-ray crystallography. Purification of MdtM was enhanced by introduction of an elongated His-tag, followed by identification and subsequent removal of chaperonin contamination. For crystallization trials of MdtM, detergent screening using size exclusion chromatography determined that decylmaltoside (DM) was the shortest-chain detergent that maintained the protein in a stable, monodispersed state. Crystallization trials of MdtM performed using the hanging-drop diffusion method with commercially available crystallization screens yielded 3D protein crystals under several different conditions. We contend that the purification protocol described here may be employed for production of high-quality protein of other multidrug efflux members of the MFS, a ubiquitous, physiologically and clinically important class of membrane transporters.
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35
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Wang D, Liang H, Chen J, Mou Y, Qi Y. Structural and Environmental Features of NovelMdfAVariant andMdfAGenes in Recombinant Regions ofEscherichia coli. Microb Drug Resist 2014; 20:392-8. [PMID: 24684286 DOI: 10.1089/mdr.2013.0201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Dongguo Wang
- Department of Clinical Lab Medicine, Taizhou University affiliated Taizhou Municipal Hospital, Taizhou, China
- Institute of Molecular Diagnostics of Taizhou University, Taizhou, China
| | - Haiyan Liang
- Department of Neurology, Taizhou University affiliated Taizhou Municipal Hospital, Taizhou, China
| | - Jiayu Chen
- Department of Lab Medicine, Medical College of Taizhou University, Taizhou, China
- Institute of Molecular Diagnostics of Taizhou University, Taizhou, China
| | - Yonghua Mou
- Department of Hepatobiliary Surgery, Taizhou Municipal Hospital of Taizhou University, Taizhou, China
| | - Yongxiao Qi
- Department of Lab Medicine, Medical College of Taizhou University, Taizhou, China
- Institute of Molecular Diagnostics of Taizhou University, Taizhou, China
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36
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Export of a single drug molecule in two transport cycles by a multidrug efflux pump. Nat Commun 2014; 5:4615. [DOI: 10.1038/ncomms5615] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/07/2014] [Indexed: 11/08/2022] Open
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37
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Paul S, Alegre KO, Holdsworth SR, Rice M, Brown JA, McVeigh P, Kelly SM, Law CJ. A single-component multidrug transporter of the major facilitator superfamily is part of a network that protects Escherichia coli from bile salt stress. Mol Microbiol 2014; 92:872-84. [PMID: 24684269 PMCID: PMC4235344 DOI: 10.1111/mmi.12597] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2014] [Indexed: 01/16/2023]
Abstract
Resistance to high concentrations of bile salts in the human intestinal tract is vital for the survival of enteric bacteria such as Escherichia coli. Although the tripartite AcrAB-TolC efflux system plays a significant role in this resistance, it is purported that other efflux pumps must also be involved. We provide evidence from a comprehensive suite of experiments performed at two different pH values (7.2 and 6.0) that reflect pH conditions that E. coli may encounter in human gut that MdtM, a single-component multidrug resistance transporter of the major facilitator superfamily, functions in bile salt resistance in E. coli by catalysing secondary active transport of bile salts out of the cell cytoplasm. Furthermore, assays performed on a chromosomal ΔacrB mutant transformed with multicopy plasmid encoding MdtM suggested a functional synergism between the single-component MdtM transporter and the tripartite AcrAB-TolC system that results in a multiplicative effect on resistance. Substrate binding experiments performed on purified MdtM demonstrated that the transporter binds to cholate and deoxycholate with micromolar affinity, and transport assays performed on inverted vesicles confirmed the capacity of MdtM to catalyse electrogenic bile salt/H(+) antiport.
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Affiliation(s)
- Stephanie Paul
- Institute for Global Food Security, School of Biological Sciences, Medical Biology Centre, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7BL, UK
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38
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Masureel M, Martens C, Stein RA, Mishra S, Ruysschaert JM, Mchaourab HS, Govaerts C. Protonation drives the conformational switch in the multidrug transporter LmrP. Nat Chem Biol 2014; 10:149-55. [PMID: 24316739 PMCID: PMC4749020 DOI: 10.1038/nchembio.1408] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 10/18/2013] [Indexed: 02/07/2023]
Abstract
Multidrug antiporters of the major facilitator superfamily couple proton translocation to the extrusion of cytotoxic molecules. The conformational changes that underlie the transport cycle and the structural basis of coupling of these transporters have not been elucidated. Here we used extensive double electron-electron resonance measurements to uncover the conformational equilibrium of LmrP, a multidrug transporter from Lactococcus lactis, and to investigate how protons and ligands shift this equilibrium to enable transport. We find that the transporter switches between outward-open and outward-closed conformations, depending on the protonation states of specific acidic residues forming a transmembrane protonation relay. Our data can be framed in a model of transport wherein substrate binding initiates the transport cycle by opening the extracellular side. Subsequent protonation of membrane-embedded acidic residues induces substrate release to the extracellular side and triggers a cascade of conformational changes that concludes in proton release to the intracellular side.
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Affiliation(s)
- Matthieu Masureel
- 1] Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Brussels, Belgium. [2]
| | - Chloé Martens
- 1] Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Brussels, Belgium. [2]
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Smriti Mishra
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jean-Marie Ruysschaert
- Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Brussels, Belgium
| | - Hassane S Mchaourab
- 1] Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, USA. [2]
| | - Cédric Govaerts
- 1] Laboratory for the Structure and Function of Biological Membranes, Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, Brussels, Belgium. [2]
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39
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Members of the conserved DedA family are likely membrane transporters and are required for drug resistance in Escherichia coli. Antimicrob Agents Chemother 2013; 58:923-30. [PMID: 24277026 DOI: 10.1128/aac.02238-13] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial resistance to antibiotics and biocides is an increasing public health problem. Genes encoding integral membrane proteins belonging to the DedA family are present in most bacterial genomes, including Escherichia coli. An E. coli strain lacking partially redundant DedA family genes yqjA and yghB (strain BC202) displays temperature sensitivity and cell division defects. These phenotypes can be corrected by overexpression of mdfA, an Na(+)-K(+)/H(+) antiporter of the major facilitator superfamily. We show that BC202 is hypersensitive to several biocides and cationic compounds that are known substrates of several multidrug resistance transporters, including MdfA, EmrE, and AcrB. The introduction of deletions of genes encoding these drug transporters into BC202 results in additional sensitivity. Expression of wild-type yghB or yqjA can restore drug resistance, but this is eliminated upon mutation of two membrane-embedded acidic amino acids (E39 or D51 in either protein). This dependence upon membrane-embedded acidic amino acids is a hallmark of proton-dependent antiporters. Overexpression of mdfA in BC202 or artificially restoring proton motive force (PMF) restores wild-type resistance to substrates of MdfA as well as other drug resistance transporters such as EmrE and AcrAB. These results suggest that YqjA and YghB may be membrane transporters required for PMF-dependent drug efflux in E. coli.
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40
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Paltansing S, Tengeler AC, Kraakman MEM, Claas ECJ, Bernards AT. Exploring the contribution of efflux on the resistance to fluoroquinolones in clinical isolates of Escherichia coli. Microb Drug Resist 2013; 19:469-76. [PMID: 23909485 DOI: 10.1089/mdr.2013.0058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Resistance to ciprofloxacin in Escherichia coli is increasing parallel to increased use of fluoroquinolones both in The Netherlands and in other European countries. The objective was to investigate the contribution of active efflux and expression of outer membrane proteins (OMPs) in a collection of clinical E. coli isolates collected at a clinical microbiology department in a Dutch hospital. Forty-seven E. coli isolates a wide range of ciprofloxacin minimum inhibitory concentrations and known mutations in the quinolone resistance determining region were included. A fluorometric determination of bisbenzimide efflux was used two different efflux pump inhibitors and compared to quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for the expression levels of acrA, acrB, tolC, yhiV, and mdfA efflux pump genes and the OMPs ompF and ompX. Six isolates (12.7%) showed increased efflux. Although in 35 isolates (76%), overexpression of ≥1 efflux pump genes using qRT-PCR was present. Only the combined overexpression of acrAB-TolC and mdfA correlated with the phenotypic efflux assay using glucose/carbonyl cyanide m-chlorophenylhydrazone with glucose. Thus, efflux was involved in ciprofloxacin resistance in a limited number of E. coli isolates collected at a clinical microbiology department in a Dutch hospital complementing other resistance mechanisms.
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Affiliation(s)
- Sunita Paltansing
- Department of Medical Microbiology, Leiden University Medical Center , Leiden, The Netherlands
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41
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Holdsworth SR, Law CJ. Multidrug resistance protein MdtM adds to the repertoire of antiporters involved in alkaline pH homeostasis in Escherichia coli. BMC Microbiol 2013; 13:113. [PMID: 23701827 PMCID: PMC3668916 DOI: 10.1186/1471-2180-13-113] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 05/20/2013] [Indexed: 12/04/2022] Open
Abstract
Background In neutralophilic bacteria, monovalent metal cation/H+ antiporters play a key role in pH homeostasis. In Escherichia coli, only four antiporters (NhaA, NhaB, MdfA and ChaA) are identified to function in maintenance of a stable cytoplasmic pH under conditions of alkaline stress. We hypothesised that the multidrug resistance protein MdtM, a recently characterised homologue of MdfA and a member of the major facilitator superfamily, also functions in alkaline pH homeostasis. Results Assays that compared the growth of an E. coli ΔmdtM deletion mutant transformed with a plasmid encoding wild-type MdtM or the dysfunctional MdtM D22A mutant at different external alkaline pH values (ranging from pH 8.5 to 10) revealed a potential contribution by MdtM to alkaline pH tolerance, but only when millimolar concentrations of sodium or potassium was present in the growth medium. Fluorescence-based activity assays using inverted vesicles generated from transformants of antiporter-deficient (ΔnhaA, ΔnhaB, ΔchaA) E. coli TO114 cells defined MdtM as a low-affinity antiporter that catalysed electrogenic exchange of Na+, K+, Rb+ or Li+ for H+. The K+/H+ antiport reaction had a pH optimum at 9.0, whereas the Na+/H+ exchange activity was optimum at pH 9.25. Measurement of internal cellular pH confirmed MdtM as contributing to maintenance of a stable cytoplasmic pH, acid relative to the external pH, under conditions of alkaline stress. Conclusions Taken together, the results support a role for MdtM in alkaline pH tolerance. MdtM can therefore be added to the currently limited list of antiporters known to function in pH homeostasis in the model organism E. coli.
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Affiliation(s)
- Scarlett R Holdsworth
- Institute for Global Food Security, School of Biological Sciences, Medical Biology Centre, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK
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Roles of AtpI and two YidC-type proteins from alkaliphilic Bacillus pseudofirmus OF4 in ATP synthase assembly and nonfermentative growth. J Bacteriol 2012; 195:220-30. [PMID: 23123906 DOI: 10.1128/jb.01493-12] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AtpI, a membrane protein encoded by many bacterial atp operons, is reported to be necessary for c-ring oligomer formation during assembly of some ATP synthase complexes. We investigated chaperone functions of AtpI and compared them to those of AtpZ, a protein encoded by a gene upstream of atpI that has a role in magnesium acquisition at near-neutral pH, and of SpoIIIJ and YqjG, two YidC/OxaI/Alb3 family proteins, in alkaliphilic Bacillus pseudofirmus OF4. A strain with a chromosomal deletion of atpI grew nonfermentatively, and its purified ATP synthase had a c-ring of normal size, indicating that AtpI is not absolutely required for ATP synthase function. However, deletion of atpI, but not atpZ, led to reduced stability of the ATP synthase rotor, reduced membrane association of the F(1) domain, reduced ATPase activity, and modestly reduced nonfermentative growth on malate at both pH 7.5 and 10.5. Both spoIIIJ and yqjG, but not atpI or atpZ, complemented a YidC-depleted Escherichia coli strain. Consistent with such overlapping functions, single deletions of spoIIIJ or yqjG in the alkaliphile did not affect membrane ATP synthase levels or activities, but functional specialization was indicated by YqjG and SpoIIIJ showing respectively greater roles in malate growth at pH 7.5 and 10.5. Expression of yqjG was elevated at pH 7.5 relative to that at pH 10.5 and in ΔspoIIIJ strains, but it was lower than constitutive spoIIIJ expression. Deletion of atpZ caused the largest increase among the mutants in magnesium concentrations needed for pH 7.5 growth. The basis for this phenotype is not yet resolved.
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Abstract
The DedA protein family is a highly conserved and ancient family of membrane proteins with representatives in most sequenced genomes, including those of bacteria, archaea, and eukarya. The functions of the DedA family proteins remain obscure. However, recent genetic approaches have revealed important roles for certain bacterial DedA family members in membrane homeostasis. Bacterial DedA family mutants display such intriguing phenotypes as cell division defects, temperature sensitivity, altered membrane lipid composition, elevated envelope-related stress responses, and loss of proton motive force. The DedA family is also essential in at least two species of bacteria: Borrelia burgdorferi and Escherichia coli. Here, we describe the phylogenetic distribution of the family and summarize recent progress toward understanding the functions of the DedA membrane protein family.
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Multiple envelope stress response pathways are activated in an Escherichia coli strain with mutations in two members of the DedA membrane protein family. J Bacteriol 2012; 195:12-24. [PMID: 23042993 DOI: 10.1128/jb.00762-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have reported that simultaneous deletion of two Escherichia coli genes, yqjA and yghB, encoding related and conserved inner membrane proteins belonging to the DedA protein family results in a number of intriguing phenotypes, including temperature sensitivity at 42°C, altered membrane lipid composition, and cell division defects. We sought to characterize these and other phenotypes in an effort to establish a function for this protein family in E. coli. Here, using reporter assays, we show that the major envelope stress response pathways Cpx, Psp, Bae, and Rcs are activated in strain BC202 (W3110; ΔyqjA ΔyghB) at the permissive growth temperature of 30°C. We previously demonstrated that 10 mM Mg(2+), 400 mM NaCl, and overexpression of tatABC are capable of restoring normal growth to BC202 at elevated growth temperatures. Deletion of the cpxR gene from BC202 results in the loss of the ability of these supplements to restore growth at 42°C. Additionally, we report that the membrane potential of BC202 is significantly reduced and that cell division and growth can be restored either by expression of the multidrug transporter MdfA from a multicopy plasmid or by growth at pH 6.0. Together, these results suggest that the DedA family proteins YqjA and YghB are required for general envelope maintenance and homeostasis of the proton motive force under a variety of growth conditions.
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Manipulating the drug/proton antiport stoichiometry of the secondary multidrug transporter MdfA. Proc Natl Acad Sci U S A 2012; 109:12473-8. [PMID: 22802625 DOI: 10.1073/pnas.1203632109] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multidrug transporters are integral membrane proteins that use cellular energy to actively extrude antibiotics and other toxic compounds from cells. The multidrug/proton antiporter MdfA from Escherichia coli exchanges monovalent cationic substrates for protons with a stoichiometry of 1, meaning that it translocates only one proton per antiport cycle. This may explain why transport of divalent cationic drugs by MdfA is energetically unfavorable. Remarkably, however, we show that MdfA can be easily converted into a divalent cationic drug/≥ 2 proton-antiporter, either by random mutagenesis or by rational design. The results suggest that exchange of divalent cationi c drugs with two (or more) protons requires an additional acidic residue in the multidrug recognition pocket of MdfA. This outcome further illustrates the exceptional promiscuous capabilities of multidrug transporters.
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Functional and biochemical characterisation of the Escherichia coli major facilitator superfamily multidrug transporter MdtM. Biochimie 2012; 94:1334-46. [DOI: 10.1016/j.biochi.2012.03.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Accepted: 03/01/2012] [Indexed: 01/22/2023]
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Gao M, Wang L, Chen SF. Metagenome cloning and functional analysis of Na⁺/H⁺ antiporter genes from Keke Salt Lake in China. Curr Microbiol 2011; 64:179-84. [PMID: 22101456 DOI: 10.1007/s00284-011-0053-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 11/07/2011] [Indexed: 11/24/2022]
Abstract
Na⁺/H⁺ antiporters are ubiquitous membrane proteins and play a central role in cell homeostasis including pH regulation, osmoregulation, and Na⁺/Li⁺ tolerance in bacteria. The microbial communities in extremely hypersaline soil are an important resource for isolating Na⁺/H⁺ antiporter genes. A metagenomic library containing 35,700 clones was constructed by using genomic DNA obtained from the hypersaline soil samples of Keke Salt Lake in Northwest of China. Two Na⁺/H⁺ antiporters, K1-NhaD, and K2-NhaD belonging to NhaD family, were screened and cloned from this metagenome by complementing the triple mutant Escherichia coli strain KNabc (nhaA⁻, nhaB⁻, chaA⁻) in medium containing 0.2 M NaCl. K1-NhaD and K2-NhaD have 75.5% identity at the predicted amino acid sequence. K1-NhaD has 78% identity with Na⁺/H⁺ antiporter NhaD from Halomonas elongate at the predicted amino acid sequence. The predicted K1-NhaD is a 53.5 kDa protein (487 amino acids) with 13 transmembrane helices. K2-NhaD has 73% identity with Alkalimonas amylolytica NhaD. The predicted K2-NhaD is a 55 kDa protein (495 amino acids) with 12 transmembrane helices. Both K1-NhaD and K2-NhaD could make the triple mutant E. coli KNabc (nhaA⁻, nhaB⁻, chaA⁻) grow in the LBK medium containing 0.2-0.6 M Na⁺ or with 0.05-0.4 M Li⁺. Everted membrane vesicles prepared from E. coli KNabc cells carrying K1-NhaD or K2-NhaD exhibited Na⁺/H⁺ and Li⁺/H⁺ antiporter activities which were pH-dependent with the highest activity at pH 9.5. Little K⁺/H⁺ antiporter activity was also detected in vesicles form E. coli KNabc carrying K1-NhaD or K2-NhaD.
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Affiliation(s)
- Maio Gao
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, People's Republic of China
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Schaedler TA, van Veen HW. A flexible cation binding site in the multidrug major facilitator superfamily transporter LmrP is associated with variable proton coupling. FASEB J 2010; 24:3653-61. [PMID: 20472749 DOI: 10.1096/fj.10-156927] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The multidrug major facilitator superfamily transporter LmrP from Lactococcus lactis mediates protonmotive-force dependent efflux of amphiphilic ligands from the cell. We compared the role of membrane-embedded carboxylates in transport and binding of divalent cationic propidium and monovalent cationic ethidium. D235N, E327Q, and D142N replacements each resulted in loss of electrogenicity in the propidium efflux reaction, pointing to electrogenic 3H(+)/propidium(2+) antiport. During ethidium efflux, single D142N and D235N replacements resulted in apparent loss of electrogenicity, whereas the E327Q substitution did not affect the energetics, consistent with electrogenic 2H(+)/ethidium(+) antiport. Different roles of carboxylates were also observed in fluorescence anisotropy-based ligand-binding assays. Whereas D235 and E327 were both involved in propidium binding, the loss of one of these carboxylates could be compensated for by the other in ethidium binding. The D142N replacement did not affect the binding of either ligand. These data point to the presence of a dedicated proton binding site containing D142, and a flexible proton/ligand binding site containing D235 and E327, the contributions to proton and ligand binding of which depend on the chemical structure of the bound ligand. Our findings provide the first evidence that multidrug transport by secondary-active transporters can be associated with variable ion coupling.
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Affiliation(s)
- Theresia A Schaedler
- Department of Pharmacology, University of Cambridge, Tennis Court Rd., Cambridge CB2 1PD, UK
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Zgurskaya HI. Multicomponent drug efflux complexes: architecture and mechanism of assembly. Future Microbiol 2009; 4:919-32. [PMID: 19722844 DOI: 10.2217/fmb.09.62] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Multidrug efflux pumps are major contributors to intrinsic antibiotic resistance in Gram-negative pathogens. The basic structure of these pumps comprises an inner membrane transporter, a periplasmic membrane fusion protein and an outer membrane channel. However, the architecture and composition of multidrug efflux complexes vary significantly because of the topological and functional diversity of the inner membrane transporters. This article presents the current views on architecture and assembly of multicomponent drug efflux transporters from Gram-negative bacteria.
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Affiliation(s)
- Helen I Zgurskaya
- Department of Chemistry & Biochemistry, University of Oklahoma, 620 Parrington Oval, Room 208, Norman, OK 73019, USA.
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Drug transport mechanism of the AcrB efflux pump. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1794:782-93. [DOI: 10.1016/j.bbapap.2008.12.015] [Citation(s) in RCA: 220] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 12/18/2008] [Accepted: 12/19/2008] [Indexed: 02/08/2023]
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