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Morris SM, Wiens L, Rose O, Fritz G, Rogers T, Gebhard S. Regulatory interactions between daptomycin- and bacitracin-responsive pathways coordinate the cell envelope antibiotic resistance response of Enterococcus faecalis. Mol Microbiol 2024. [PMID: 38646792 DOI: 10.1111/mmi.15264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/23/2024]
Abstract
Enterococcal infections frequently show high levels of antibiotic resistance, including to cell envelope-acting antibiotics like daptomycin (DAP). While we have a good understanding of the resistance mechanisms, less is known about the control of such resistance genes in enterococci. Previous work unveiled a bacitracin resistance network, comprised of the sensory ABC transporter SapAB, the two-component system (TCS) SapRS and the resistance ABC transporter RapAB. Interestingly, components of this system have recently been implicated in DAP resistance, a role usually regulated by the TCS LiaFSR. To better understand the regulation of DAP resistance and how this relates to mutations observed in DAP-resistant clinical isolates of enterococci, we here explored the interplay between these two regulatory pathways. Our results show that SapR regulates an additional resistance operon, dltXABCD, a known DAP resistance determinant, and show that LiaFSR regulates the expression of sapRS. This regulatory structure places SapRS-target genes under dual control, where expression is directly controlled by SapRS, which itself is up-regulated through LiaFSR. The network structure described here shows how Enterococcus faecalis coordinates its response to cell envelope attack and can explain why clinical DAP resistance often emerges via mutations in regulatory components.
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Affiliation(s)
- Sali M Morris
- Life Sciences Department, Milner Centre for Evolution, University of Bath, Bath, UK
| | - Laura Wiens
- Institute of Molecular Physiology, Johannes-Gutenberg-University Mainz, Mainz, Germany
| | - Olivia Rose
- Life Sciences Department, Milner Centre for Evolution, University of Bath, Bath, UK
| | - Georg Fritz
- School of Molecular Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Tim Rogers
- Department of Mathematical Sciences, University of Bath, Bath, UK
| | - Susanne Gebhard
- Life Sciences Department, Milner Centre for Evolution, University of Bath, Bath, UK
- Institute of Molecular Physiology, Johannes-Gutenberg-University Mainz, Mainz, Germany
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2
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Ali L, Abdel Aziz MH. Crosstalk involving two-component systems in Staphylococcus aureus signaling networks. J Bacteriol 2024; 206:e0041823. [PMID: 38456702 PMCID: PMC11025333 DOI: 10.1128/jb.00418-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024] Open
Abstract
Staphylococcus aureus poses a serious global threat to human health due to its pathogenic nature, adaptation to environmental stress, high virulence, and the prevalence of antimicrobial resistance. The signaling network in S. aureus coordinates and integrates various internal and external inputs and stimuli to adapt and formulate a response to the environment. Two-component systems (TCSs) of S. aureus play a central role in this network where surface-expressed histidine kinases (HKs) receive and relay external signals to their cognate response regulators (RRs). Despite the purported high fidelity of signaling, crosstalk within TCSs, between HK and non-cognate RR, and between TCSs and other systems has been detected widely in bacteria. The examples of crosstalk in S. aureus are very limited, and there needs to be more understanding of its molecular recognition mechanisms, although some crosstalk can be inferred from similar bacterial systems that share structural similarities. Understanding the cellular processes mediated by this crosstalk and how it alters signaling, especially under stress conditions, may help decipher the emergence of antibiotic resistance. This review highlights examples of signaling crosstalk in bacteria in general and S. aureus in particular, as well as the effect of TCS mutations on signaling and crosstalk.
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Affiliation(s)
- Liaqat Ali
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
| | - May H. Abdel Aziz
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, Texas, USA
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3
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Silberberg JM, Ketter S, Böhm PJN, Jordan K, Wittenberg M, Grass J, Hänelt I. KdpD is a tandem serine histidine kinase that controls K + pump KdpFABC transcriptionally and post-translationally. Nat Commun 2024; 15:3223. [PMID: 38622146 PMCID: PMC11018627 DOI: 10.1038/s41467-024-47526-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/04/2024] [Indexed: 04/17/2024] Open
Abstract
Two-component systems, consisting of a histidine kinase and a response regulator, serve signal transduction in bacteria, often regulating transcription in response to environmental stimuli. Here, we identify a tandem serine histidine kinase function for KdpD, previously described as a histidine kinase of the KdpDE two-component system, which controls production of the potassium pump KdpFABC. We show that KdpD additionally mediates an inhibitory serine phosphorylation of KdpFABC at high potassium levels, using not its C-terminal histidine kinase domain but an N-terminal atypical serine kinase domain. Sequence analysis of KdpDs from different species highlights that some KdpDs are much shorter than others. We show that, while Escherichia coli KdpD's atypical serine kinase domain responds directly to potassium levels, a shorter version from Deinococcus geothermalis is controlled by second messenger cyclic di-AMP. Our findings add to the growing functional diversity of sensor kinases while simultaneously expanding the framework for regulatory mechanisms in bacterial potassium homeostasis.
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Affiliation(s)
- Jakob M Silberberg
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany
| | - Sophie Ketter
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany
| | - Paul J N Böhm
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany
| | - Kristin Jordan
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany
| | - Marcel Wittenberg
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany
| | - Julia Grass
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany
| | - Inga Hänelt
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt/Main, Germany.
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4
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Orlando BJ. Perception and protection: The role of Bce-modules in antimicrobial peptide resistance. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184309. [PMID: 38460782 PMCID: PMC11009047 DOI: 10.1016/j.bbamem.2024.184309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/18/2024] [Accepted: 03/04/2024] [Indexed: 03/11/2024]
Abstract
Continual synthesis and remodeling of the peptidoglycan layer surrounding Gram-positive cells is essential for their survival. Diverse antimicrobial peptides target the lipid intermediates involved in this process. To sense and counteract assault from antimicrobial peptides, low G + C content gram-positive bacteria (Firmicutes) have evolved membrane protein complexes known as Bce-modules. These complexes consist minimally of an ABC transporter and a two-component system that work in tandem to perceive and confer resistance against antimicrobial peptides. In this mini-review I highlight recent breakthroughs in comprehending the structure and function of these unusual membrane protein complexes, with a particular focus on the BceAB-RS system present in Bacillus subtilis.
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Affiliation(s)
- Benjamin J Orlando
- Dept. of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA.
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5
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Janet-Maitre M, Job V, Bour M, Robert-Genthon M, Brugière S, Triponney P, Cobessi D, Couté Y, Jeannot K, Attrée I. Pseudomonas aeruginosa MipA-MipB envelope proteins act as new sensors of polymyxins. mBio 2024; 15:e0221123. [PMID: 38345374 PMCID: PMC10936184 DOI: 10.1128/mbio.02211-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 01/09/2024] [Indexed: 03/14/2024] Open
Abstract
Due to the rising incidence of antibiotic-resistant infections, the last-line antibiotics, polymyxins, have resurged in the clinics in parallel with new bacterial strategies of escape. The Gram-negative opportunistic pathogen Pseudomonas aeruginosa develops resistance to colistin/polymyxin B by distinct molecular mechanisms, mostly through modification of the lipid A component of the LPS by proteins encoded within the arnBCDATEF-ugd (arn) operon. In this work, we characterized a polymyxin-induced operon named mipBA, present in P. aeruginosa strains devoid of the arn operon. We showed that mipBA is activated by the ParR/ParS two-component regulatory system in response to polymyxins. Structural modeling revealed that MipA folds as an outer-membrane β-barrel, harboring an internal negatively charged channel, able to host a polymyxin molecule, while the lipoprotein MipB adopts a β-lactamase fold with two additional C-terminal domains. Experimental work confirmed that MipA and MipB localize to the bacterial envelope, and they co-purify in vitro. Nano differential scanning fluorimetry showed that polymyxins stabilized MipA in a specific and dose-dependent manner. Mass spectrometry-based quantitative proteomics on P. aeruginosa membranes demonstrated that ∆mipBA synthesized fourfold less MexXY-OprA proteins in response to polymyxin B compared to the wild-type strain. The decrease was a direct consequence of impaired transcriptional activation of the mex operon operated by ParR/ParS. We propose MipA/MipB to act as membrane (co)sensors working in concert to activate ParS histidine kinase and help the bacterium to cope with polymyxin-mediated envelope stress through synthesis of the efflux pump, MexXY-OprA.IMPORTANCEDue to the emergence of multidrug-resistant isolates, antibiotic options may be limited to polymyxins to eradicate Gram-negative infections. Pseudomonas aeruginosa, a leading opportunistic pathogen, has the ability to develop resistance to these cationic lipopeptides by modifying its lipopolysaccharide through proteins encoded within the arn operon. Herein, we describe a sub-group of P. aeruginosa strains lacking the arn operon yet exhibiting adaptability to polymyxins. Exposition to sub-lethal polymyxin concentrations induced the expression and production of two envelope-associated proteins. Among those, MipA, an outer-membrane barrel, is able to specifically bind polymyxins with an affinity in the 10-µM range. Using membrane proteomics and phenotypic assays, we showed that MipA and MipB participate in the adaptive response to polymyxins via ParR/ParS regulatory signaling. We propose a new model wherein the MipA-MipB module functions as a novel polymyxin sensing mechanism.
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Affiliation(s)
- Manon Janet-Maitre
- Team Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, IBS, UMR5075, Grenoble, France
| | - Viviana Job
- Team Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, IBS, UMR5075, Grenoble, France
| | - Maxime Bour
- UMR6249 Chrono-Environnement, UFR Santé, University of Franche-Comté, Besançon, France
- French National Reference Center for Antibiotic Resistance, Besançon, France
| | - Mylène Robert-Genthon
- Team Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, IBS, UMR5075, Grenoble, France
| | - Sabine Brugière
- University Grenoble Alpes, CEA, INSERM, UA13 BGE, CNRS, CEA, FranceGrenoble
| | - Pauline Triponney
- French National Reference Center for Antibiotic Resistance, Besançon, France
| | - David Cobessi
- University Grenoble Alpes, IBS, UMR5075, Team Synchrotron, Grenoble, France
| | - Yohann Couté
- University Grenoble Alpes, CEA, INSERM, UA13 BGE, CNRS, CEA, FranceGrenoble
| | - Katy Jeannot
- UMR6249 Chrono-Environnement, UFR Santé, University of Franche-Comté, Besançon, France
- French National Reference Center for Antibiotic Resistance, Besançon, France
- Department of Bacteriology, Teaching Hospital of Besançon, Besançon, France
| | - Ina Attrée
- Team Bacterial Pathogenesis and Cellular Responses, University Grenoble Alpes, IBS, UMR5075, Grenoble, France
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Zhang Q, Zúñiga M, Alcántara C, Wolf D, Mascher T, Revilla-Guarinos A. Cross-regulation of Aps-promoters in Lacticaseibacillus paracasei by the PsdR response regulator in response to lantibiotics. Sci Rep 2024; 14:3319. [PMID: 38336830 PMCID: PMC10858260 DOI: 10.1038/s41598-024-53592-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 02/01/2024] [Indexed: 02/12/2024] Open
Abstract
The PsdRSAB and ApsRSAB detoxification modules, together with the antimicrobial peptides (AMPs)-resistance determinants Dlt system and MprF protein, play major roles in the response to AMPs in Lacticaseibacillus paracasei BL23. Sensitivity assays with a collection of mutants showed that the PsdAB ABC transporter and the Dlt system are the main subtilin resistance determinants. Quantification of the transcriptional response to subtilin indicate that this response is exclusively regulated by the two paralogous systems PsdRSAB and ApsRSAB. Remarkably, a cross-regulation of the derAB, mprF and dlt-operon genes-usually under control of ApsR-by PsdR in response to subtilin was unveiled. The high similarity of the predicted structures of both response regulators (RR), and of the RR-binding sites support this possibility, which we experimentally verified by protein-DNA binding studies. ApsR-P shows a preferential binding in the order PderA > Pdlt > PmprF > PpsdA. However, PsdR-P bound with similar apparent affinity constants to the four promoters. This supports the cross-regulation of derAB, mprF and the dlt-operon by PsdR. The possibility of cross-regulation at the level of RR-promoter interaction allows some regulatory overlap with two RRs controlling the expression of systems involved in maintenance of critical cell membrane functions in response to lantibiotics.
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Affiliation(s)
- Qian Zhang
- Chair of General Microbiology, Technische Universität Dresden, 01217, Dresden, Germany
| | - Manuel Zúñiga
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), 46980, Paterna, Valencia, Spain
| | - Cristina Alcántara
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), 46980, Paterna, Valencia, Spain
| | - Diana Wolf
- Chair of General Microbiology, Technische Universität Dresden, 01217, Dresden, Germany
| | - Thorsten Mascher
- Chair of General Microbiology, Technische Universität Dresden, 01217, Dresden, Germany.
| | - Ainhoa Revilla-Guarinos
- Chair of General Microbiology, Technische Universität Dresden, 01217, Dresden, Germany.
- Oral Microbiome Group, Genomics and Health Department, FISABIO Foundation, 46020, Valencia, Spain.
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7
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Faure A, Manuse S, Gonin M, Grangeasse C, Jault JM, Orelle C. Daptomycin avoids drug resistance mediated by the BceAB transporter in Streptococcus pneumoniae. Microbiol Spectr 2024; 12:e0363823. [PMID: 38214521 PMCID: PMC10846014 DOI: 10.1128/spectrum.03638-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 12/19/2023] [Indexed: 01/13/2024] Open
Abstract
Drug-resistant bacteria are a serious threat to human health as antibiotics are gradually losing their clinical efficacy. Comprehending the mechanism of action of antimicrobials and their resistance mechanisms plays a key role in developing new agents to fight antimicrobial resistance. The lipopeptide daptomycin is an antibiotic that selectively disrupts Gram-positive bacterial membranes, thereby showing slower resistance development than many classical drugs. Consequently, it is often used as a last resort antibiotic to preserve its use as one of the least potent antibiotics at our disposal. The mode of action of daptomycin has been debated but was recently found to involve the formation of a tripartite complex between undecaprenyl precursors of cell wall biosynthesis and the anionic phospholipid phosphatidylglycerol. BceAB-type ABC transporters are known to confer resistance to antimicrobial peptides that sequester some precursors of the peptidoglycan, such as the undecaprenyl pyrophosphate or lipid II. The expression of these transporters is upregulated by dedicated two-component regulatory systems in the presence of antimicrobial peptides that are recognized by the system. Here, we investigated whether daptomycin evades resistance mediated by the BceAB transporter from the bacterial pathogen Streptococcus pneumoniae. Although daptomycin can bind to the transporter, our data showed that the BceAB transporter does not mediate resistance to the drug and its expression is not induced in its presence. These findings show that the pioneering membrane-active daptomycin has the potential to escape the resistance mechanism mediated by BceAB-type transporters and confirm that the development of this class of compounds has promising clinical applications.IMPORTANCEAntibiotic resistance is rising in all parts of the world. New resistance mechanisms are emerging and dangerously spreading, threatening our ability to treat common infectious diseases. Daptomycin is an antimicrobial peptide that is one of the last antibiotics approved for clinical use. Understanding the resistance mechanisms toward last-resort antibiotics such as daptomycin is critical for the success of future antimicrobial therapies. BceAB-type ABC transporters confer resistance to antimicrobial peptides that target precursors of cell-wall synthesis. In this study, we showed that the BceAB transporter from the human pathogen Streptococcus pneumoniae does not confer resistance to daptomycin, suggesting that this drug and other calcium-dependent lipopeptide antibiotics have the potential to evade the action of this type of ABC transporters in other bacterial pathogens.
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Affiliation(s)
- Agathe Faure
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Sylvie Manuse
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Mathilde Gonin
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Jean-Michel Jault
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Cédric Orelle
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
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8
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George NL, Orlando BJ. Architecture of a complete Bce-type antimicrobial peptide resistance module. Nat Commun 2023; 14:3896. [PMID: 37393310 PMCID: PMC10314905 DOI: 10.1038/s41467-023-39678-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/23/2023] [Indexed: 07/03/2023] Open
Abstract
Gram-positive bacteria synthesize and secrete antimicrobial peptides that target the essential process of peptidoglycan synthesis. These antimicrobial peptides not only regulate the dynamics of microbial communities but are also of clinical importance as exemplified by peptides such as bacitracin, vancomycin, and daptomycin. Many gram-positive species have evolved specialized antimicrobial peptide sensing and resistance machinery known as Bce modules. These modules are membrane protein complexes formed by an unusual Bce-type ABC transporter interacting with a two-component system sensor histidine kinase. In this work, we provide the first structural insight into how the membrane protein components of these modules assemble into a functional complex. A cryo-EM structure of an entire Bce module revealed an unexpected mechanism of complex assembly, and extensive structural flexibility in the sensor histidine kinase. Structures of the complex in the presence of a non-hydrolysable ATP analog reveal how nucleotide binding primes the complex for subsequent activation. Accompanying biochemical data demonstrate how the individual membrane protein components of the complex exert functional control over one another to create a tightly regulated enzymatic system.
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Affiliation(s)
- Natasha L George
- Dept. of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
- Dept. of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, USA
| | - Benjamin J Orlando
- Dept. of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
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Zhu J, Wang S, Wang C, Wang Z, Luo G, Li J, Zhan Y, Cai D, Chen S. Microbial synthesis of bacitracin: Recent progress, challenges, and prospects. Synth Syst Biotechnol 2023; 8:314-322. [PMID: 37122958 PMCID: PMC10130698 DOI: 10.1016/j.synbio.2023.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/12/2023] [Accepted: 03/23/2023] [Indexed: 05/02/2023] Open
Abstract
Microorganisms are important sources of various natural products that have been commercialized for human medicine and animal healthcare. Bacitracin is an important antibacterial natural product predominantly produced by Bacillus licheniformis and Bacillus subtilis, and it is characterized by a broad antimicrobial spectrum, strong activity and low resistance, thus bacitracin is extensively applied in animal feed and veterinary medicine industries. In recent years, various strategies have been proposed to improve bacitracin production. Herein, we systematically describe the regulation of bacitracin biosynthesis in genus Bacillus and its associated mechanism, to provide a theoretical basis for bacitracin overproduction. The metabolic engineering strategies applied for bacitracin production are explored, including improving substrate utilization, using an enlarged precursor amino acid pool, increasing ATP supply and NADPH generation, and engineering transcription regulators. We also present several approaches of fermentation process optimization to facilitate the industrial large-scale production of bacitracin. Finally, the challenges and prospects associated with microbial bacitracin synthesis are discussed to facilitate the establishment of high-yield and low-cost biological factories.
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Affiliation(s)
- Jiang Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Shiyi Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Cheng Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Zhi Wang
- Hubei Provincial Key Laboratory of Industrial Microbiology, Key Laboratory of Fermentation Engineering (Ministry of Education), School of Food and Biological Engineering, Hubei University of Technology, Wuhan, 430068, Hubei, PR China
| | - Gan Luo
- Lifecome Biochemistry Co. Ltd, Nanping, 353400, PR China
| | - Junhui Li
- Lifecome Biochemistry Co. Ltd, Nanping, 353400, PR China
| | - Yangyang Zhan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
- Corresponding author.
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
- Corresponding author. 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, PR China.
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10
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Popp PF, Lozano-Cruz T, Dürr F, Londaitsbehere A, Hartig J, de la Mata FJ, Gómez R, Mascher T, Revilla-Guarinos A. The Novel Synthetic Antibiotic BDTL049 Based on a Dendritic System Induces Lipid Domain Formation while Escaping the Cell Envelope Stress Resistance Determinants. Pharmaceutics 2023; 15:297. [PMID: 36678925 PMCID: PMC9866484 DOI: 10.3390/pharmaceutics15010297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/17/2023] Open
Abstract
The threat of antimicrobial-resistant bacteria is ever increasing and over the past-decades development of novel therapeutic counter measurements have virtually come to a halt. This circumstance calls for interdisciplinary approaches to design, evaluate and validate the mode of action of novel antibacterial compounds. Hereby, carbosilane dendritic systems that exhibit antimicrobial properties have the potential to serve as synthetic and rationally designed molecules for therapeutic use. The bow-tie type topology of BDTL049 was recently investigated against the Gram-positive model organism Bacillus subtilis, revealing strong bactericidal properties. In this study, we follow up on open questions concerning the usability of BDTL049. For this, we synthesized a fluorescent-labeled version of BDTL049 that maintained all antimicrobial features to unravel the interaction of the compound and bacterial membrane. Subsequently, we highlight the bacterial sensitivity against BDTL049 by performing a mutational study of known resistance determinants. Finally, we address the cytotoxicity of the compound in human cells, unexpectedly revealing a high sensitivity of the eukaryotic cells upon BDTL049 exposure. The insights presented here further elaborate on the unique features of BDTL049 as a promising candidate as an antimicrobial agent while not precluding that further rounds of rational designing are needed to decrease cytotoxicity to ultimately pave the way for synthetic antibiotics toward clinical applicability.
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Affiliation(s)
- Philipp F. Popp
- Department of General Microbiology, Institut Für Mikrobiologie, Technische Universität Dresden, 01217 Dresden, Germany
| | - Tania Lozano-Cruz
- Department of Organic and Inorganic Chemistry, Research Institute in Chemistry “Andrés M. Del Río” (IQAR), University de Alcalá, 28805 Madrid, Spain
- Ramón y Cajal Health Research Institute (IRYCIS), 28805 Madrid, Spain
- Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28805 Madrid, Spain
| | - Franziska Dürr
- Department of General Microbiology, Institut Für Mikrobiologie, Technische Universität Dresden, 01217 Dresden, Germany
| | - Addis Londaitsbehere
- Department of Organic and Inorganic Chemistry, Research Institute in Chemistry “Andrés M. Del Río” (IQAR), University de Alcalá, 28805 Madrid, Spain
| | - Johanna Hartig
- Department of General Microbiology, Institut Für Mikrobiologie, Technische Universität Dresden, 01217 Dresden, Germany
| | - Francisco Javier de la Mata
- Department of Organic and Inorganic Chemistry, Research Institute in Chemistry “Andrés M. Del Río” (IQAR), University de Alcalá, 28805 Madrid, Spain
- Ramón y Cajal Health Research Institute (IRYCIS), 28805 Madrid, Spain
- Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28805 Madrid, Spain
| | - Rafael Gómez
- Department of Organic and Inorganic Chemistry, Research Institute in Chemistry “Andrés M. Del Río” (IQAR), University de Alcalá, 28805 Madrid, Spain
- Ramón y Cajal Health Research Institute (IRYCIS), 28805 Madrid, Spain
- Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28805 Madrid, Spain
| | - Thorsten Mascher
- Department of General Microbiology, Institut Für Mikrobiologie, Technische Universität Dresden, 01217 Dresden, Germany
| | - Ainhoa Revilla-Guarinos
- Department of General Microbiology, Institut Für Mikrobiologie, Technische Universität Dresden, 01217 Dresden, Germany
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11
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Hao W, Cui W, Suo F, Han L, Cheng Z, Zhou Z. Construction and application of an efficient dual-base editing platform for Bacillus subtilis evolution employing programmable base conversion. Chem Sci 2022; 13:14395-14409. [PMID: 36545152 PMCID: PMC9749471 DOI: 10.1039/d2sc05824c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/20/2022] [Indexed: 12/03/2022] Open
Abstract
The functionally evolved bacterial chassis is of great importance to manufacture a group of assorted high value-added chemicals, from small molecules to biologically active macromolecules. However, the current evolution frameworks are less efficienct in generating in vivo genomic diversification because of insufficient tunability, rendering limited evolution spacing for chassis. Here, an engineered genomic diversification platform (CRISPR-ABE8e-CDA-nCas9) leveraging a programmable dual-deaminases base editor was fabricated for rapidly evolving bacterial chassis. The dual-base editor was constructed by reprogramming the CRISPR array, nCas9, and cytidine and adenosine deaminase, enabling single or multiple base conversion at the genomic scale by simultaneous C-to-T and A-to-G conversion in vivo. Employing titration of the Cas-deaminase fusion protein, the platform enabled editing any pre-defined genomic loci with tunable conversion efficiency and editable window, generating a repertoire of mutants with highly diversified genomic sequences. Leveraging the genomic diversification platform, we successfully evolved the nisin-resistant capability of Bacillus subtilis through directed evolution of the subunit of lantibiotic ATP-binding cassette. Therefore, our work provides a portable and programmable genomic diversification platform, which is promising to expedite the fabrication of high-performance and robust bacterial chassis used in the development of biomanufacturing and biopharmaceuticals.
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Affiliation(s)
- Wenliang Hao
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University1800 Lihu AvenueWuxi 214122JiangsuChina
| | - Wenjing Cui
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University1800 Lihu AvenueWuxi 214122JiangsuChina
| | - Feiya Suo
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University1800 Lihu AvenueWuxi 214122JiangsuChina
| | - Laichuang Han
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University1800 Lihu AvenueWuxi 214122JiangsuChina
| | - Zhongyi Cheng
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University1800 Lihu AvenueWuxi 214122JiangsuChina
| | - Zhemin Zhou
- The Key Laboratory of Industrial Biotechnology (Ministry of Education), School of Biotechnology, Jiangnan University1800 Lihu AvenueWuxi 214122JiangsuChina
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Kurdrid P, Yutthanasirikul R, Saree S, Senachak J, Saelee M, Hongsthong A. Hik28-dependent and Hik28-independent ABC transporters were revealed by proteome-wide analysis of ΔHik28 under combined stress. BMC Mol Cell Biol 2022; 23:27. [PMID: 35794554 PMCID: PMC9258054 DOI: 10.1186/s12860-022-00421-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/07/2022] [Indexed: 11/30/2022] Open
Abstract
Synechocystis histidine kinase, Sll0474: Hik28, a signal protein in a two-component signal transduction system, plays a critical role in responding to a decrease in growth temperature and is also involved in nitrogen metabolism. In the present study, under combined stress from non-optimal growth temperature and nitrogen depletion, a comparative proteomic analysis of the wild type (WT) and a deletion mutant (MT) of Synechocystis histidine kinase, Sll0474: Hik28, in a two-component signal transduction system identified the specific groups of ABC transporters that were Hik28-dependent, e.g., the iron transporter, and Hik28-independent, e.g., the phosphate transporter. The iron transporter, AfuA, was found to be upregulated only in the WT strain grown under the combined stress of high temperature and nitrogen depletion. Whereas, the expression level of the phosphate transporter, PstS, was increased in both the WT and MT strains. Moreover, the location in the genome of the genes encoding Hik28 and ABC transporters in Synechocystis sp. PCC6803 were analyzed in parallel with the comparative proteomic data. The results suggested the regulation of the ABC transporters by the gene in a two-component system located in an adjacent location in the genome.
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Cho J, Rigby WFC, Cheung AL. The thematic role of extracellular loop of VraG in activation of the membrane sensor GraS in a cystic fibrosis MRSA strain differs in nuance from the CA-MRSA strain JE2. PLoS One 2022; 17:e0270393. [PMID: 35737676 PMCID: PMC9223312 DOI: 10.1371/journal.pone.0270393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/09/2022] [Indexed: 11/19/2022] Open
Abstract
Patients with cystic fibrosis (CF) often suffer recurrent bronchial bacterial infections that lead to deterioration of lung function over time. The infections in CF patients are often due to S. aureus and P. aeruginosa that colonize the airways. Significantly, methicillin-resistant S. aureus (MRSA) makes it challenging for treatment in CF patients due to its feature of multiple antibiotic resistance. In bronchial airways, cationic antimicrobial peptides are often present in mucosa cells, neutrophils, and macrophages that interfere with bacterial proliferation. The major mechanism for resistance to the bactericidal activity of cationic peptides in S. aureus is mediated by the GraRS two-component system that activates expression of MprF and DltABCD to increase surface positive charge to repel interactions with cationic peptides. We recently found that VraG, a membrane permease component of the VraFG efflux pumps, harbors a long 200-residue extracellular loop (EL) that utilizes K380 to interact with the negatively charged 9-residue extracellular loop of the membrane sensor GraS to control mprF expression in a community-acquired MRSA strain JE2. In this study, we extended this observation to a CF MRSA strain CF32A1 where we affirmed that the EL loop of VraG controls GraS-mediated signal transduction; however, in contrast to community acquired MRSA strain JE2, the CF MRSA strain CF32A1 requires both K380 and K388 in the EL of VraG to properly modulate signal transduction mediated by GraS. This effect was not attributable to the several single nucleotide polymorphisms that exist between VraG and GraS in the two MRSA strains.
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Affiliation(s)
- Junho Cho
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
- * E-mail:
| | - William F. C. Rigby
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Medicine, Geisel School of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States of America
| | - Ambrose L. Cheung
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
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Yang J, Barra JT, Fung DK, Wang JD. Bacillus subtilis produces (p)ppGpp in response to the bacteriostatic antibiotic chloramphenicol to prevent its potential bactericidal effect. MLIFE 2022; 1:101-113. [PMID: 38817674 PMCID: PMC10989873 DOI: 10.1002/mlf2.12031] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 05/24/2022] [Indexed: 06/01/2024]
Abstract
Antibiotics combat bacteria through their bacteriostatic (by growth inhibition) or bactericidal (by killing bacteria) action. Mechanistically, it has been proposed that bactericidal antibiotics trigger cellular damage, while bacteriostatic antibiotics suppress cellular metabolism. Here, we demonstrate how the difference between bacteriostatic and bactericidal activities of the antibiotic chloramphenicol can be attributed to an antibiotic-induced bacterial protective response: the stringent response. Chloramphenicol targets the ribosome to inhibit the growth of the Gram-positive bacterium Bacillus subtilis. Intriguingly, we found that chloramphenicol becomes bactericidal in B. subtilis mutants unable to produce (p)ppGpp. We observed a similar (p)ppGpp-dependent bactericidal effect of chloramphenicol in the Gram-positive pathogen Enterococcus faecalis. In B. subtilis, chloramphenicol treatment induces (p)ppGpp accumulation through the action of the (p)ppGpp synthetase RelA. (p)ppGpp subsequently depletes the intracellular concentration of GTP and antagonizes GTP action. This GTP regulation is critical for preventing chloramphenicol from killing B. subtilis, as bypassing (p)ppGpp-dependent GTP regulation potentiates chloramphenicol killing, while reducing GTP synthesis increases survival. Finally, chloramphenicol treatment protects cells from the classical bactericidal antibiotic vancomycin, reminiscent of the clinical phenomenon of antibiotic antagonism. Taken together, our findings suggest a role of (p)ppGpp in the control of the bacteriostatic and bactericidal activity of antibiotics in Gram-positive bacteria, which can be exploited to potentiate the efficacy of existing antibiotics.
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Affiliation(s)
- Jin Yang
- Department of BacteriologyUniversity of WisconsinMadisonUSA
| | | | - Danny K. Fung
- Department of BacteriologyUniversity of WisconsinMadisonUSA
| | - Jue D. Wang
- Department of BacteriologyUniversity of WisconsinMadisonUSA
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Conformational snapshots of the bacitracin sensing and resistance transporter BceAB. Proc Natl Acad Sci U S A 2022; 119:e2123268119. [PMID: 35349335 PMCID: PMC9169098 DOI: 10.1073/pnas.2123268119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
SignificanceMany gram-positive organisms have evolved an elegant solution to sense and resist antimicrobial peptides that inhibit cell-wall synthesis. These organisms express an unusual "Bce-type" adenosine triphosphate-binding cassette (ABC) transporter that recognizes complexes formed between antimicrobial peptides and lipids involved in cell-wall biosynthesis. In this work, we provide the first structural snapshots of a Bce-type ABC transporter trapped in different conformational states. Our structures and associated biochemical data provide key insights into the novel target protection mechanism that these unusual ABC transporters use to sense and resist antimicrobial peptides. The studies described herein set the stage to begin developing a comprehensive molecular understanding of the diverse interactions between antimicrobial peptides and conserved resistance machinery found across most gram-positive organisms.
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Diagne AM, Pelletier A, Durmort C, Faure A, Kanonenberg K, Freton C, Page A, Delolme F, Vorac J, Vallet S, Bellard L, Vivès C, Fieschi F, Vernet T, Rousselle P, Guiral S, Grangeasse C, Jault JM, Orelle C. Identification of a two-component regulatory system involved in antimicrobial peptide resistance in Streptococcus pneumoniae. PLoS Pathog 2022; 18:e1010458. [PMID: 35395062 PMCID: PMC9020739 DOI: 10.1371/journal.ppat.1010458] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 04/20/2022] [Accepted: 03/18/2022] [Indexed: 11/24/2022] Open
Abstract
Two-component regulatory systems (TCS) are among the most widespread mechanisms that bacteria use to sense and respond to environmental changes. In the human pathogen Streptococcus pneumoniae, a total of 13 TCS have been identified and many of them have been linked to pathogenicity. Notably, TCS01 strongly contributes to pneumococcal virulence in several infection models. However, it remains one of the least studied TCS in pneumococci and its functional role is still unclear. In this study, we demonstrate that TCS01 cooperates with a BceAB-type ABC transporter to sense and induce resistance to structurally-unrelated antimicrobial peptides of bacterial origin that all target undecaprenyl-pyrophosphate or lipid II, which are essential precursors of cell wall biosynthesis. Even though tcs01 and bceAB genes do not locate in the same gene cluster, disruption of either of them equally sensitized the bacterium to the same set of antimicrobial peptides. We show that the key function of TCS01 is to upregulate the expression of the transporter, while the latter appears the main actor in resistance. Electrophoretic mobility shift assays further demonstrated that the response regulator of TCS01 binds to the promoter region of the bceAB genes, implying a direct control of these genes. The BceAB transporter was overexpressed and purified from E. coli. After reconstitution in liposomes, it displayed substantial ATPase and GTPase activities that were stimulated by antimicrobial peptides to which it confers resistance to, revealing new functional features of a BceAB-type transporter. Altogether, this inducible defense mechanism likely contributes to the survival of the opportunistic microorganism in the human host, in which competition among commensal microorganisms is a key determinant for effective host colonization and invasive path. Streptococcus pneumoniae is a commensal bacterium of the human nasopharynx that can switch to an invasive pathogen causing a variety of diseases, leading to over one million deaths worldwide each year. The sophisticated strategies that allow S. pneumoniae to survive in various environments within the human body are still poorly understood. One of the most widespread tools that enable bacteria to sense environmental changes and to promote adaptative responses by modulating gene expression are two-component regulatory systems (TCS). TCS01 was identified as an important virulence factor, and understanding its biological function is key to comprehend bacterial pathogenesis. In this study, we demonstrated that this TCS upregulates the expression of an ABC transporter that mediates resistance to bacterial antimicrobial peptides targeting cell wall synthesis. Because competition among microorganisms is a key element for host colonization and persistence, our findings contribute to explain the potent role of TCS01 in bacterial survival within the human host.
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Affiliation(s)
- Aissatou Maty Diagne
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Anaïs Pelletier
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Claire Durmort
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Agathe Faure
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Kerstin Kanonenberg
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Céline Freton
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Adeline Page
- Protein Science Facility, SFR BioSciences, CNRS, UMS3444, INSERM US8, University of Lyon, Lyon, France
| | - Frédéric Delolme
- Protein Science Facility, SFR BioSciences, CNRS, UMS3444, INSERM US8, University of Lyon, Lyon, France
| | - Jaroslav Vorac
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Sylvain Vallet
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Laure Bellard
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Corinne Vivès
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Franck Fieschi
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Thierry Vernet
- Institute of Structural Biology (IBS), UMR 5075 CNRS/University of Grenoble-Alpes, Grenoble, France
| | - Patricia Rousselle
- Laboratoire de Biologie Tissulaire et Ingénierie Thérapeutique (LBTI), UMR 5305 CNRS/University of Lyon, Lyon, France
| | - Sébastien Guiral
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Jean-Michel Jault
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
| | - Cédric Orelle
- Molecular Microbiology and Structural Biochemistry (MMSB), UMR 5086 CNRS/University of Lyon, Lyon, France
- * E-mail:
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Gottstein J, Zaschke-Kriesche J, Unsleber S, Voitsekhovskaia I, Kulik A, Behrmann LV, Overbeck N, Stühler K, Stegmann E, Smits SHJ. New insights into the resistance mechanism for the BceAB-type transporter SaNsrFP. Sci Rep 2022; 12:4232. [PMID: 35273305 PMCID: PMC8913810 DOI: 10.1038/s41598-022-08095-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 02/23/2022] [Indexed: 11/16/2022] Open
Abstract
Treatment of bacterial infections is one of the major challenges of our time due to the evolved resistance mechanisms of pathogens against antibiotics. To circumvent this problem, it is necessary to understand the mode of action of the drug and the mechanism of resistance of the pathogen. One of the most potent antibiotic targets is peptidoglycan (PGN) biosynthesis, as this is an exclusively occurring and critical feature of bacteria. Lipid II is an essential PGN precursor synthesized in the cytosol and flipped into the outer leaflet of the membrane prior to its incorporation into nascent PGN. Antimicrobial peptides (AMPs), such as nisin and colistin, targeting PGN synthesis are considered promising weapons against multidrug-resistant bacteria. However, human pathogenic bacteria that were also resistant to these compounds evolved by the expression of an ATP-binding cassette transporter of the bacitracin efflux (BceAB) type localized in the membrane. In the human pathogen Streptococcus agalactiae, the BceAB transporter SaNsrFP is known to confer resistance to the antimicrobial peptide nisin. The exact mechanism of action for SaNsrFP is poorly understood. For a detailed characterization of the resistance mechanism, we heterologously expressed SaNsrFP in Lactococcus lactis. We demonstrated that SaNsrFP conferred resistance not only to nisin but also to a structurally diverse group of antimicrobial PGN-targeting compounds such as ramoplanin, lysobactin, or bacitracin/(Zn)-bacitracin. Growth experiments revealed that SaNsrFP-producing cells exhibited normal behavior when treated with nisin and/or bacitracin, in contrast to the nonproducing cells, for which growth was significantly reduced. We further detected the accumulation of PGN precursors in the cytoplasm after treating the cells with bacitracin. This did not appear when SaNsrFP was produced. Whole-cell proteomic protein experiments verified that the presence of SaNsrFP in L. lactis resulted in higher production of several proteins associated with cell wall modification. These included, for example, the N-acetylmuramic acid-6-phosphate etherase MurQ and UDP-glucose 4-epimerase. Analysis of components of the cell wall of SaNsrFP-producing cells implied that the transporter is involved in cell wall modification. Since we used an ATP-deficient mutant of the transporter as a comparison, we can show that SaNsrFP and its inactive mutant do not show the same phenotype, albeit expressed at similar levels, which demonstrates the ATP dependency of the mediated resistance processes. Taken together, our data agree to a target protection mechanism and imply a direct involvement of SaNsrFP in resistance by shielding the membrane-localized target of these antimicrobial peptides, resulting in modification of the cell wall.
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Affiliation(s)
- Julia Gottstein
- Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Julia Zaschke-Kriesche
- Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Sandra Unsleber
- Interfaculty Institute of Microbiology and Infection Medicin, Eberhard Karls University, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Irina Voitsekhovskaia
- Interfaculty Institute of Microbiology and Infection Medicin, Eberhard Karls University, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Andreas Kulik
- Interfaculty Institute of Microbiology and Infection Medicin, Eberhard Karls University, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Lara V Behrmann
- Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Nina Overbeck
- Molecular Proteomics Laboratory, Heinrich-Heine-University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Kai Stühler
- Molecular Proteomics Laboratory, Heinrich-Heine-University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany
| | - Evi Stegmann
- Interfaculty Institute of Microbiology and Infection Medicin, Eberhard Karls University, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich-Heine-University Duesseldorf, Universitaetsstrasse 1, 40225, Duesseldorf, Germany.
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18
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Characterization of a Novel Linezolid Resistance Gene optrA and Bacitracin Resistance Locus-Carrying Multiple Antibiotic Resistant Integrative and Conjugative Element ICE Ssu1112S in Streptococccus Suis. Microbiol Spectr 2022; 10:e0196321. [PMID: 35170998 PMCID: PMC8849049 DOI: 10.1128/spectrum.01963-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Streptococcus suis strain 1112S was isolated from a diseased pig in a feedlot from Henan, China, in 2019. The isolate harbored a linezolid resistance gene optrA. WGS data revealed that the optrA gene was associated with a single copy ETAf ISS1S, in tandem with erm(B) and tet(O), located in a novel 72,587 bp integrative and conjugative element (ICE). Notably, this novel element, designated ICESsu1112S, also carried a novel bacitracin resistance locus. ICESsu1112S could be excised from chromosome and transferred to the recipient strain S. suis P1/7 with a frequency of 5.9 × 10−6 transconjugants per donor cell. This study provided the first description of the coexistence of optrA and a novel bacitracin locus on a multiple antibiotic resistant ICE and highlighted that ICE were major vehicle and contribute to the potential transfer of clinically relevant antibiotic resistance genes. IMPORTANCE Antimicrobial resistance (AMR) caused by the imprudent use of antimicrobials has become a global problem, which poses a serious threat to treatment of S. suis infection in pigs and humans. Importantly, AMR genes can horizontally spread among commensal organisms and pathogenic microbiota, thereby accelerating the dissemination of AMR determinants. These transfers are mainly mediated by mobile genetic elements, including ICEs. In S. suis, ICEs are the major vehicles that contribute to the natural transfers of AMR genes among different bacterial pathogens. However, ICEs that carry optrA and bacitracin resistance locus are rarely investigated in S. suis isolates. Here, we investigated a S. suis isolate carrying an optrA and a novel bacitracin resistance locus, which were co-located on a novel multiple antibiotic resistant ICESsu1112S. Our study suggests that more research is needed to access the real significance of ICEs that horizontally spread clinical important resistance genes.
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Ou T, Zhang M, Huang Y, Wang L, Wang F, Wang R, Liu X, Zhou Z, Xie J, Xiang Z. Role of Rhizospheric Bacillus megaterium HGS7 in Maintaining Mulberry Growth Under Extremely Abiotic Stress in Hydro-Fluctuation Belt of Three Gorges Reservoir. FRONTIERS IN PLANT SCIENCE 2022; 13:880125. [PMID: 35712602 PMCID: PMC9195505 DOI: 10.3389/fpls.2022.880125] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 03/17/2022] [Indexed: 05/03/2023]
Abstract
Plant growth-promoting rhizobacteria have been shown to play important roles in maintaining host fitness under periods of abiotic stress, and yet their effect on mulberry trees which regularly suffer drought after flooding in the hydro-fluctuation belt of the Three Gorges Reservoir Region in China remains largely uncharacterized. In the present study, 74 bacterial isolates were obtained from the rhizosphere soil of mulberry after drought stress, including 12 phosphate-solubilizing and 10 indole-3-acetic-acid-producing isolates. Bacillus megaterium HGS7 was selected for further study due to the abundance of traits that might benefit plants. Genomic analysis revealed that strain HGS7 possessed multiple genes that contributed to plant growth promotion, stress tolerance enhancement, and antimicrobial compound production. B. megaterium HGS7 consistently exhibited antagonistic activity against phytopathogens and strong tolerance to abiotic stress in vitro. Moreover, this strain stimulated mulberry seed germination and seedling growth. It may also induce the production of proline and antioxidant enzymes in mulberry trees to enhance drought tolerance and accelerate growth recovery after drought stress. The knowledge of the interactions between rhizobacteria HGS7 and its host plant might provide a potential strategy to enhance the drought tolerance of mulberry trees in a hydro-fluctuation belt.
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Affiliation(s)
- Ting Ou
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Meng Zhang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Yazhou Huang
- Kaizhou District Nature Reserve Management Center, Chongqing, China
| | - Li Wang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Fei Wang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Ruolin Wang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Xiaojiao Liu
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Zeyang Zhou
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- College of Life Sciences, Chongqing Normal University, Chongqing, China
| | - Jie Xie
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- *Correspondence: Jie Xie,
| | - Zhonghuai Xiang
- State Key Laboratory of Silkworm Genome Biology, Key Laboratory of Sericultural Biology and Genetic Breeding in Ministry of Agriculture, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
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20
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Vimberg V, Buriánková K, Mazumdar A, Branny P, Novotná GB. Role of membrane proteins in bacterial resistance to antimicrobial peptides. Med Res Rev 2021; 42:1023-1036. [PMID: 34796517 DOI: 10.1002/med.21869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 09/19/2021] [Accepted: 10/21/2021] [Indexed: 11/07/2022]
Abstract
Several natural antimicrobial peptides (AMPs), including the novel semisynthetic lipoglycopeptide antibiotics telavancin, dalbavancin, and oritavancin, have been approved for clinical use to address the growing problem of multiple antibiotic-resistant Gram-positive bacterial infections. Nevertheless, the efficacy of these antibiotics has already been compromised. The SARS-CoV-2 pandemic led to the increased clinical use of all antibiotics, further promoting the development of bacterial resistance. Therefore, it is critical to gain a deeper understanding of the role of resistance mechanisms to minimize the consequential risks of long-term antibiotic use and misuse. Here, we summarize for the first time the current knowledge of resistance mechanisms that have been shown to cause resistance to clinically used AMPs, with particular focus on membrane proteins that have been reported to interfere with the activity of AMPs by affecting the binding of AMPs to bacteria.
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Affiliation(s)
- Vladimir Vimberg
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Karolína Buriánková
- Laboratory of Cell Signaling, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Aninda Mazumdar
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Pavel Branny
- Laboratory of Cell Signaling, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
| | - Gabriela B Novotná
- Laboratory for Biology of Secondary Metabolism, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czechia
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Lactococcus lactis Resistance to Aureocin A53- and Enterocin L50-Like Bacteriocins and Membrane-Targeting Peptide Antibiotics Relies on the YsaCB-KinG-LlrG Four-Component System. Antimicrob Agents Chemother 2021; 65:e0092121. [PMID: 34516250 DOI: 10.1128/aac.00921-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Resistance to nonribosomally synthesized peptide antibiotics affecting the cell envelope is well studied and mostly associated with the action of peptide-sensing and detoxification (PSD) modules, which consist of a two-component system (TCS) and an ATP-binding cassette (ABC) transporter. In contrast, the mechanisms of resistance to ribosomally synthesized bacterial toxic peptides (bacteriocins), which also affect the cell envelope, are studied to a lesser extent, and the possible cross-resistance between them and antibiotics is still poorly understood. In the present study, we investigated the development of resistance of Lactococcus lactis to aureocin A53- and enterocin L50-like bacteriocins and cross-resistance with antibiotics. First, 19 spontaneous mutants resistant to their representatives were selected and also displayed changes in sensitivity to peptide antibiotics acting on the cell envelope (bacitracin, daptomycin, and gramicidin). Sequencing of their genomes revealed mutations in genes encoding the ABC transporter YsaCB and the TCS KinG-LlrG, the emergence of which induced the upregulation of the dltABCD and ysaDCB operons. The ysaB mutations were either nonsense or frameshift mutations and led to the generation of truncated YsaB but with the conserved N-terminal FtsX domain intact. Deletions of ysaCB or llrG had a minor effect on the resistance of the obtained mutants to the tested bacteriocins, daptomycin, and gramicidin, indicating that the development of resistance is dependent on the modification of the protein rather than its absence. In further corroboration of the above-mentioned conclusion, we show that the FtsX domain, which functions effectively when YsaB is lacking its central and C-terminal parts, is critical for resistance to these antimicrobials.
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Keikha M, Karbalaei M. Probiotics as the live microscopic fighters against Helicobacter pylori gastric infections. BMC Gastroenterol 2021; 21:388. [PMID: 34670526 PMCID: PMC8527827 DOI: 10.1186/s12876-021-01977-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 10/15/2021] [Indexed: 02/07/2023] Open
Abstract
Background Helicobacter pylori (H. pylori) is the causative agent of stomach diseases such as duodenal ulcer and gastric cancer, in this regard incomplete eradication of this bacterium has become to a serious concern. Probiotics are a group of the beneficial bacteria which increase the cure rate of H. pylori infections through various mechanisms such as competitive inhibition, co-aggregation ability, enhancing mucus production, production of bacteriocins, and modulating immune response. Result In this study, according to the received articles, the anti-H. pylori activities of probiotics were reviewed. Based on studies, administration of standard antibiotic therapy combined with probiotics plays an important role in the effective treatment of H. pylori infection. According to the literature, Lactobacillus casei, Lactobacillus reuteri, Lactobacillus rhamnosus GG, and Saccharomyces boulardii can effectively eradicate H. pylori infection. Our results showed that in addition to decrease gastrointestinal symptoms, probiotics can reduce the side effects of antibiotics (especially diarrhea) by altering the intestinal microbiome. Conclusion Nevertheless, antagonist activities of probiotics are H. pylori strain-specific. In general, these bacteria can be used for therapeutic purposes such as adjuvant therapy, drug-delivery system, as well as enhancing immune system against H. pylori infection.
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Affiliation(s)
- Masoud Keikha
- Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.,Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohsen Karbalaei
- Department of Microbiology and Virology, School of Medicine, Jiroft University of Medical Sciences, Jiroft, Iran.
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23
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Villapún VM, Balacco DL, Webber MA, Hall T, Lowther M, Addison O, Kuehne SA, Grover LM, Cox SC. Repeated exposure of nosocomial pathogens to silver does not select for silver resistance but does impact ciprofloxacin susceptibility. Acta Biomater 2021; 134:760-773. [PMID: 34329788 DOI: 10.1016/j.actbio.2021.07.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 12/25/2022]
Abstract
The rise of antimicrobial resistant bacteria coupled with a void in antibiotic development marks Antimicrobial Resistance as one of the biggest current threats to modern medicine. Antimicrobial metals are being developed and used as alternative anti-infectives, however, the existence of known resistance mechanisms and limited data regarding bacterial responses to long-term metal exposure are barriers to widespread implementation. In this study, a panel of reference and clinical strains of major nosocomial pathogens were subjected to serial dosage cycles of silver and ciprofloxacin. Populations exposed to silver initially showed no change in sensitivity, however, increasingly susceptibility was observed after the 25th cycle. A control experiment with ciprofloxacin revealed a selection for resistance over time, with silver treated bacteria showing faster adaptation. Morphological analysis revealed filamentation in Gram negative species suggesting membrane perturbation, while sequencing of isolated strains identified mutations in numerous genes. These included those encoding for efflux systems, chemosensory systems, stress responses, biofilm formation and respiratory chain processes, although no consistent locus was identified that correlated with silver sensitivity. These results suggest that de novo silver resistance is hard to select in a range of nosocomial pathogens, although silver exposure may detrimentally impact sensitivity to antibiotics in the long term. STATEMENT OF SIGNIFICANCE: The adaptability of microbial life continuously calls for the development of novel antibiotic molecules, however, the cost and risk associated with their discovery have led to a drying up in the pipeline, causing antimicrobial resistance (AMR) to be a major threat to healthcare. From all available strategies, antimicrobial metals and, more specifically, silver showcase large bactericidal spectrum and limited toxic effect which coupled with a large range of processes available for their delivery made these materials as a clear candidate to tackle AMR. Previous reports have shown the ability of this metal to enact a synergistic effect with other antimicrobial therapies, nevertheless, the discovery of Ag resistance mechanisms since the early 70s and limited knowledge on the long term influence of silver on AMR poses a threat to their applicability. The present study provides quantitative data on the influence of silver based therapies on AMR development for a panel of reference and clinical strains of major nosocomial pathogens, revealing that prolonged silver exposure may detrimentally impact sensitivity to antibiotics.
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Affiliation(s)
- Victor M Villapún
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
| | - Dario L Balacco
- School of Dentistry, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Mark A Webber
- Quadram Institute Bioscience, Norwich Research Park, NR4 7UQ, United Kingdom; Norwich Medical School, University of East Anglia. Norwich Research Park, NR4 7TJ, United Kingdom
| | - Thomas Hall
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Morgan Lowther
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Owen Addison
- Faculty of Dentistry, Oral and Craniofacial Sciences, King's College London, London, SE1 9RT, United Kingdom
| | - Sarah A Kuehne
- School of Dentistry, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Liam M Grover
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom
| | - Sophie C Cox
- School of Chemical Engineering, University of Birmingham, Edgbaston B15 2TT, United Kingdom.
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24
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Zhu J, Li L, Wu F, Wu Y, Wang Z, Chen X, Li J, Cai D, Chen S. Metabolic Engineering of Aspartic Acid Supply Modules for Enhanced Production of Bacitracin in Bacillus licheniformis. ACS Synth Biol 2021; 10:2243-2251. [PMID: 34324815 DOI: 10.1021/acssynbio.1c00154] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Bacitracin, a type of cyclic dodecapeptide antibiotic mainly produced by Bacillus, is widely used in fields of veterinary drug and feed additive. Modularization of metabolic pathways based on the concept of synthetic biology has been widely used in the efficient synthesis of target products. Here, we want to improve bacitracin production through strengthening aspartic acid (Asp) supply in B. licheniformis DW2. First, exogenous Asp addition assays implied that strengthening Asp supply benefited bacitracin production. Second, Asp synthetic pathways were strengthened via overexpressing aspartate dehydrogenase AspD and asparaginase AnsB, attaining recombinant strain DW2-ASP2, and bacitracin yield produced by DW2-ASP2 was 862.81 U/mL, increased by 14.05% compared with that of DW2 (756.49 U/mL). Then, to improve precursor oxaloacetate (OAA) accumulation for Asp synthesis, pyruvate carboxylase PycA and carbonic anhydrase EcaA were co-overexpressed in DW2-ASP2, and malic enzyme gene malS was deleted to weak overflow metabolism of tricarboxylic acid, and the attained strain DW2-ASP7 showed further increased bacitracin production from 862.81 to 989.23 U/mL. Subsequently, transporter YveA was identified as an Asp exporter, and bacitracin yield was increased to 1025.26 U/mL via deleting yveA, attaining strain DW2-ASP9. Finally, Asp ammonia-lyase gene aspA was disrupted to weaken Asp degradation, and bacitracin yield of attained strain DW2-ASP10 reached 1059.86 U/mL, increased by 40.10% compared to DW2. Taken together, this research demonstrated that metabolic engineering of Asp metabolic modules is an efficient strategy for enhancing bacitracin production, and these strategies could also be applied in the production of other peptide-related metabolites.
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Affiliation(s)
- Jiang Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Lingfeng Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Fei Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Yuanxin Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Zhi Wang
- Hubei Provincial Key Laboratory of Industrial Microbiology, Key Laboratory of Fermentation Engineering (Ministry of Education), School of food and biological engineering, Hubei University of Technology, Wuhan 430068, Hubei China
| | - Xiaobin Chen
- Lifecome Biochemistry Co. Ltd, Nanping, 353400, PR China
| | - Junhui Li
- Lifecome Biochemistry Co. Ltd, Nanping, 353400, PR China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, PR China
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25
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Choyam S, Jain PM, Kammara R. Characterization of a Potent New-Generation Antimicrobial Peptide of Bacillus. Front Microbiol 2021; 12:710741. [PMID: 34504482 PMCID: PMC8421597 DOI: 10.3389/fmicb.2021.710741] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/15/2021] [Indexed: 11/13/2022] Open
Abstract
An antimicrobial peptide [Bacillus antimicrobial peptide (BAMP)] produced by Bacillus paralicheniformis was isolated from the Indian traditional fermented food and characterized. The antimicrobial peptide BAMP showed many unique features such as thermostability (4.0-125°C), pH tolerance (pH 2.0-9.0), and resistance to physiological enzymes (trypsin, chymotrypsin, pepsin, proteinase K, protease, and catalase), and food-grade metal salts do not inhibit the activity. The broad spectrum of BAMP (antimicrobial activity) makes it a suitable candidate for food preservation as well as antimicrobial therapy. BAMP was found to exhibit a bacteriostatic effect on Salmonella typhi and controls the viability of Listeria monocytogenes in chicken meat efficiently. BAMP was found to establish eubiosis, as it is not antagonistic to Lactobacillus. Its non-hemolytic nature makes it suitable for therapy. Various genome prediction tools were adopted and applied to understand their localization, gene arrangement, and type of antimicrobials. Founded on its superior functional attributes, BAMP is a potent new-generation antimicrobial peptide.
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Affiliation(s)
- Shilja Choyam
- Department of Protein Chemistry and Technology, Faculty of AcSIR, CSIR-CFTRI, Mysore, India
| | - Priyanshi M Jain
- Department of Protein Chemistry and Technology, Faculty of AcSIR, CSIR-CFTRI, Mysore, India
| | - Rajagopal Kammara
- Department of Protein Chemistry and Technology, Faculty of AcSIR, CSIR-CFTRI, Mysore, India
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26
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Costa SK, Cho J, Cheung AL. GraS Sensory Activity in Staphylococcus epidermidis Is Modulated by the "Guard Loop" of VraG and the ATPase Activity of VraF. J Bacteriol 2021; 203:e0017821. [PMID: 34096781 PMCID: PMC8351631 DOI: 10.1128/jb.00178-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/01/2021] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial peptides (AMPs) are one of the key immune responses that can eliminate pathogenic bacteria through membrane perturbation. As a successful skin commensal, Staphylococcus epidermidis can sense and respond to AMPs through the GraXRS two-component system and an efflux system comprising the VraG permease and VraF ATPase. GraS is a membrane sensor known to function in AMP resistance through a negatively charged, 9-residue extracellular loop, which is predicted to be linear without any secondary structure. An important question is how GraS can impart effective sensing of AMPs through such a small unstructured sequence. In this study, we verified the role of graS and vraG in AMP sensing in S. epidermidis, as demonstrated by the failure of the ΔgraS or ΔvraG mutants to sense. Deletion of the extracellular loop of VraG did not affect sensing but reduced survival with polymyxin B. Importantly, a specific region within the extracellular loop, termed the guard loop (GL), has inhibitory activity since sensing of polymyxin B was enhanced in the ΔGL mutant, indicating that the GL may act as a gatekeeper for sensing. Bacterial two-hybrid analysis demonstrated that the extracellular regions of GraS and VraG interact, but interaction appears dispensable to sensing activity. Mutation of the extracellular loop of VraG, the GL, and the active site of VraF suggested that an active detoxification function of VraG is necessary for AMP resistance. Altogether, we provide evidence for a unique sensory scheme that relies on the function of a permease to impart effective information processing. IMPORTANCE Staphylococcus epidermidis has become an important opportunistic pathogen that is responsible for nosocomial and device-related infections that account for considerable morbidity worldwide. A thorough understanding of the mechanisms that enable S. epidermidis to colonize human skin successfully is essential for the development of alternative treatment strategies and prophylaxis. Here, we demonstrate the importance of an AMP response system in a clinically relevant S. epidermidis strain. Furthermore, we provide evidence for a unique sensory scheme that would rely on the detoxification function of a permease to effect information processing.
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Affiliation(s)
- Stephen K. Costa
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Junho Cho
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Ambrose L. Cheung
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
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27
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Cho J, Costa SK, Wierzbicki RM, Rigby WFC, Cheung AL. The extracellular loop of the membrane permease VraG interacts with GraS to sense cationic antimicrobial peptides in Staphylococcus aureus. PLoS Pathog 2021; 17:e1009338. [PMID: 33647048 PMCID: PMC7951975 DOI: 10.1371/journal.ppat.1009338] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/11/2021] [Accepted: 01/27/2021] [Indexed: 01/27/2023] Open
Abstract
Host defense proteins (HDPs), aka defensins, are a key part of the innate immune system that functions by inserting into the bacterial membranes to form pores to kill invading and colonizing microorganisms. To ensure survival, microorganism such as S. aureus has developed survival strategies to sense and respond to HDPs. One key strategy in S. aureus is a two-component system (TCS) called GraRS coupled to an efflux pump that consists of a membrane permease VraG and an ATPase VraF, analogous to the BceRS-BceAB system of Bacillus subtilis but with distinct differences. While the 9 negatively charged amino acid extracellular loop of the membrane sensor GraS has been shown to be involved in sensing, the major question is how such a small loop can sense diverse HDPs. Mutation analysis in this study divulged that the vraG mutant phenocopied the graS mutant with respect to reduced activation of downstream effector mprF, reduction in surface positive charge and enhanced 2 hr. killing with LL-37 as compared with the parental MRSA strain JE2. In silico analysis revealed VraG contains a single 200-residue extracellular loop (EL) situated between the 7th and 8th transmembrane segments (out of 10). Remarkably, deletion of EL in VraG enhanced mprF expression, augmented surface positive charge and improved survival in LL-37 vs. parent JE2. As the EL of VraG is rich in lysine residues (16%), in contrast to a preponderance of negatively charged aspartic acid residues (3 out of 9) in the EL of GraS, we divulged the role of charge interaction by showing that K380 in the EL of VraG is an important residue that likely interacts with GraS to interfere with GraS-mediated signaling. Bacterial two-hybrid analysis also supported the interaction of EL of VraG with the EL of GraS. Collectively, we demonstrated an interesting facet of efflux pumps whereby the membrane permease disrupts HDP signaling by inhibiting GraS sensing that involves charged residues in the EL of VraG.
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Affiliation(s)
- Junho Cho
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Stephen K. Costa
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
| | - Rachel M. Wierzbicki
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Medicine, Geisel School of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States of America
| | - William F. C. Rigby
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
- Department of Medicine, Geisel School of Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States of America
| | - Ambrose L. Cheung
- Department of Microbiology and Immunology, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire, United States of America
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28
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Rismondo J, Schulz LM. Not Just Transporters: Alternative Functions of ABC Transporters in Bacillus subtilis and Listeria monocytogenes. Microorganisms 2021; 9:microorganisms9010163. [PMID: 33450852 PMCID: PMC7828314 DOI: 10.3390/microorganisms9010163] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/07/2021] [Accepted: 01/10/2021] [Indexed: 12/24/2022] Open
Abstract
ATP-binding cassette (ABC) transporters are usually involved in the translocation of their cognate substrates, which is driven by ATP hydrolysis. Typically, these transporters are required for the import or export of a wide range of substrates such as sugars, ions and complex organic molecules. ABC exporters can also be involved in the export of toxic compounds such as antibiotics. However, recent studies revealed alternative detoxification mechanisms of ABC transporters. For instance, the ABC transporter BceAB of Bacillus subtilis seems to confer resistance to bacitracin via target protection. In addition, several transporters with functions other than substrate export or import have been identified in the past. Here, we provide an overview of recent findings on ABC transporters of the Gram-positive organisms B. subtilis and Listeria monocytogenes with transport or regulatory functions affecting antibiotic resistance, cell wall biosynthesis, cell division and sporulation.
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29
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The Cell Envelope Stress Response of Bacillus subtilis towards Laspartomycin C. Antibiotics (Basel) 2020; 9:antibiotics9110729. [PMID: 33114184 PMCID: PMC7690785 DOI: 10.3390/antibiotics9110729] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 11/17/2022] Open
Abstract
Cell wall antibiotics are important tools in our fight against Gram-positive pathogens, but many strains become increasingly resistant against existing drugs. Laspartomycin C is a novel antibiotic that targets undecaprenyl phosphate (UP), a key intermediate in the lipid II cycle of cell wall biosynthesis. While laspartomycin C has been thoroughly examined biochemically, detailed knowledge about potential resistance mechanisms in bacteria is lacking. Here, we use reporter strains to monitor the activity of central resistance modules in the Bacillus subtilis cell envelope stress response network during laspartomycin C attack and determine the impact on the resistance of these modules using knock-out strains. In contrast to the closely related UP-binding antibiotic friulimicin B, which only activates ECF σ factor-controlled stress response modules, we find that laspartomycin C additionally triggers activation of stress response systems reacting to membrane perturbation and blockage of other lipid II cycle intermediates. Interestingly, none of the studied resistance genes conferred any kind of protection against laspartomycin C. While this appears promising for therapeutic use of laspartomycin C, it raises concerns that existing cell envelope stress response networks may already be poised for spontaneous development of resistance during prolonged or repeated exposure to this new antibiotic.
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30
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Smits SHJ, Schmitt L, Beis K. Self-immunity to antibacterial peptides by ABC transporters. FEBS Lett 2020; 594:3920-3942. [PMID: 33040342 DOI: 10.1002/1873-3468.13953] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/22/2020] [Accepted: 10/05/2020] [Indexed: 01/17/2023]
Abstract
Bacteria produce under certain stress conditions bacteriocins and microcins that display antibacterial activity against closely related species for survival. Bacteriocins and microcins exert their antibacterial activity by either disrupting the membrane or inhibiting essential intracellular processes of the bacterial target. To this end, they can lyse bacterial membranes and cause subsequent loss of their integrity or nutrients, or hijack membrane receptors for internalisation. Both bacteriocins and microcins are ribosomally synthesised and several are posttranslationally modified, whereas others are not. Such peptides are also toxic to the producer bacteria, which utilise immunity proteins or/and dedicated ATP-binding cassette (ABC) transporters to achieve self-immunity and peptide export. In this review, we discuss the structure and mechanism of self-protection that is conferred by these ABC transporters.
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Affiliation(s)
- Sander H J Smits
- Institute of Biochemistry, Heinrich-Heine-University, Duesseldorf, Germany.,Center for Structural Studies, Heinrich-Heine-University, Duesseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich-Heine-University, Duesseldorf, Germany
| | - Konstantinos Beis
- Department of Life Sciences, Imperial College London, UK.,Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, UK
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31
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Assoni L, Milani B, Carvalho MR, Nepomuceno LN, Waz NT, Guerra MES, Converso TR, Darrieux M. Resistance Mechanisms to Antimicrobial Peptides in Gram-Positive Bacteria. Front Microbiol 2020; 11:593215. [PMID: 33193264 PMCID: PMC7609970 DOI: 10.3389/fmicb.2020.593215] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 09/03/2020] [Indexed: 02/06/2023] Open
Abstract
With the alarming increase of infections caused by pathogenic multidrug-resistant bacteria over the last decades, antimicrobial peptides (AMPs) have been investigated as a potential treatment for those infections, directly through their lytic effect or indirectly, due to their ability to modulate the immune system. There are still concerns regarding the use of such molecules in the treatment of infections, such as cell toxicity and host factors that lead to peptide inhibition. To overcome these limitations, different approaches like peptide modification to reduce toxicity and peptide combinations to improve therapeutic efficacy are being tested. Human defense peptides consist of an important part of the innate immune system, against a myriad of potential aggressors, which have in turn developed different ways to overcome the AMPs microbicidal activities. Since the antimicrobial activity of AMPs vary between Gram-positive and Gram-negative species, so do the bacterial resistance arsenal. This review discusses the mechanisms exploited by Gram-positive bacteria to circumvent killing by antimicrobial peptides. Specifically, the most clinically relevant genera, Streptococcus spp., Staphylococcus spp., Enterococcus spp. and Gram-positive bacilli, have been explored.
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Affiliation(s)
- Lucas Assoni
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Barbara Milani
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Marianna Ribeiro Carvalho
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Lucas Natanael Nepomuceno
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Natalha Tedeschi Waz
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Maria Eduarda Souza Guerra
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Thiago Rojas Converso
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
| | - Michelle Darrieux
- Laboratório de Biologia Molecular de Microrganismos, Universidade São Francisco, Bragança Paulista, Brazil
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32
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Koh A, Gibbon MJ, Van der Kamp MW, Pudney CR, Gebhard S. Conformation control of the histidine kinase BceS of Bacillus subtilis by its cognate ABC-transporter facilitates need-based activation of antibiotic resistance. Mol Microbiol 2020; 115:157-174. [PMID: 32955745 DOI: 10.1111/mmi.14607] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/09/2020] [Accepted: 09/09/2020] [Indexed: 12/15/2022]
Abstract
Bacteria closely control gene expression to ensure optimal physiological responses to their environment. Such careful gene expression can minimize the fitness cost associated with antibiotic resistance. We previously described a novel regulatory logic in Bacillus subtilis enabling the cell to directly monitor its need for detoxification. This cost-effective strategy is achieved via a two-component regulatory system (BceRS) working in a sensory complex with an ABC-transporter (BceAB), together acting as a flux-sensor where signaling is proportional to transport activity. How this is realized at the molecular level has remained unknown. Using experimentation and computation we here show that the histidine kinase is activated by piston-like displacements in the membrane, which are converted to helical rotations in the catalytic core via an intervening HAMP-like domain. Intriguingly, the transporter was not only required for kinase activation, but also to actively maintain the kinase in its inactive state in the absence of antibiotics. Such coupling of kinase activity to that of the transporter ensures the complete control required for transport flux-dependent signaling. Moreover, we show that the transporter likely conserves energy by signaling with sub-maximal sensitivity. These results provide the first mechanistic insights into transport flux-dependent signaling, a unique strategy for energy-efficient decision making.
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Affiliation(s)
- Alan Koh
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Milner Centre for Evolution, University of Bath, Bath, UK
| | - Marjorie J Gibbon
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Milner Centre for Evolution, University of Bath, Bath, UK
| | | | | | - Susanne Gebhard
- Department of Biology and Biochemistry, University of Bath, Bath, UK.,Milner Centre for Evolution, University of Bath, Bath, UK
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Revilla-Guarinos A, Dürr F, Popp PF, Döring M, Mascher T. Amphotericin B Specifically Induces the Two-Component System LnrJK: Development of a Novel Whole-Cell Biosensor for the Detection of Amphotericin-Like Polyenes. Front Microbiol 2020; 11:2022. [PMID: 32973732 PMCID: PMC7472640 DOI: 10.3389/fmicb.2020.02022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/30/2020] [Indexed: 11/13/2022] Open
Abstract
The rise of drug-resistant fungal pathogens urges for the development of new tools for the discovery of novel antifungal compounds. Polyene antibiotics are potent agents against fungal infections in humans and animals. They inhibit the growth of fungal cells by binding to sterols in the cytoplasmic membrane that subsequently causes pore formation and eventually results in cell death. Many polyenes are produced by Streptomycetes and released into the soil environment, where they can then target fungal hyphae. While not antibacterial, these compounds could nevertheless be also perceived by bacteria sharing the same habitat and serve as signaling molecules. We therefore addressed the question of how polyenes such as amphotericin B are perceived by the soil bacterium, Bacillus subtilis. Global transcriptional profiling identified a very narrow and specific response, primarily resulting in strong upregulation of the lnrLMN operon, encoding an ABC transporter previously associated with linearmycin resistance. Its strong and specific induction prompted a detailed analysis of the lnrL promoter element and its regulation. We demonstrate that the amphotericin response strictly depends on the two-component system LnrJK and that the target of LnrK-dependent gene regulation, the lnrLMN operon, negatively affects LnrJK-dependent signal transduction. Based on this knowledge, we developed a novel whole-cell biosensor, based on a PlnrL-lux fusion reporter construct in a lnrLMN deletion mutant background. This highly sensitive and dynamic biosensor is ready to be applied for the discovery or characterization of novel amphotericin-like polyenes, hopefully helping to increase the repertoire of antimycotic and antiparasitic polyenes available to treat human and animal infections.
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Affiliation(s)
- Ainhoa Revilla-Guarinos
- Department of General Microbiology, Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Franziska Dürr
- Department of General Microbiology, Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Philipp F Popp
- Department of General Microbiology, Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Maximilian Döring
- Department of General Microbiology, Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Thorsten Mascher
- Department of General Microbiology, Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
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Bernal-Cabas M, Miethke M, Antelo-Varela M, Aguilar Suárez R, Neef J, Schön L, Gabarrini G, Otto A, Becher D, Wolf D, van Dijl JM. Functional association of the stress-responsive LiaH protein and the minimal TatAyCy protein translocase in Bacillus subtilis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118719. [DOI: 10.1016/j.bbamcr.2020.118719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/07/2020] [Accepted: 04/09/2020] [Indexed: 01/07/2023]
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Revilla-Guarinos A, Zhang Q, Loderer C, Alcántara C, Müller A, Rahnamaeian M, Vilcinskas A, Gebhard S, Zúñiga M, Mascher T. ABC Transporter DerAB of Lactobacillus casei Mediates Resistance against Insect-Derived Defensins. Appl Environ Microbiol 2020; 86:e00818-20. [PMID: 32414796 PMCID: PMC7357469 DOI: 10.1128/aem.00818-20] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/09/2020] [Indexed: 01/28/2023] Open
Abstract
Bce-like systems mediate resistance against antimicrobial peptides in Firmicutes bacteria. Lactobacillus casei BL23 encodes an "orphan" ABC transporter that, based on homology to BceAB-like systems, was proposed to contribute to antimicrobial peptide resistance. A mutant lacking the permease subunit was tested for sensitivity against a collection of peptides derived from bacteria, fungi, insects, and humans. Our results show that the transporter specifically conferred resistance against insect-derived cysteine-stabilized αβ defensins, and it was therefore renamed DerAB for defensin resistance ABC transporter. Surprisingly, cells lacking DerAB showed a marked increase in resistance against the lantibiotic nisin. This could be explained by significantly increased expression of the antimicrobial peptide resistance determinants regulated by the Bce-like systems PsdRSAB (formerly module 09) and ApsRSAB (formerly module 12). Bacterial two-hybrid studies in Escherichia coli showed that DerB could interact with proteins of the sensory complex in the Psd resistance system. We therefore propose that interaction of DerAB with this complex in the cell creates signaling interference and reduces the cell's potential to mount an effective nisin resistance response. In the absence of DerB, this negative interference is relieved, leading to the observed hyperactivation of the Psd module and thus increased resistance to nisin. Our results unravel the function of a previously uncharacterized Bce-like orphan resistance transporter with pleiotropic biological effects on the cell.IMPORTANCE Antimicrobial peptides (AMPs) play an important role in suppressing the growth of microorganisms. They can be produced by bacteria themselves-to inhibit competitors-but are also widely distributed in higher eukaryotes, including insects and mammals, where they form an important component of innate immunity. In low-GC-content Gram-positive bacteria, BceAB-like transporters play a crucial role in AMP resistance but have so far been primarily associated with interbacterial competition. Here, we show that the orphan transporter DerAB from the lactic acid bacterium Lactobacillus casei is crucial for high-level resistance against insect-derived AMPs. It therefore represents an important mechanism for interkingdom defense. Furthermore, our results support a signaling interference from DerAB on the PsdRSAB module that might prevent the activation of a full nisin response. The Bce modules from L. casei BL23 illustrate a biological paradox in which the intrinsic nisin detoxification potential only arises in the absence of a defensin-specific ABC transporter.
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Affiliation(s)
| | - Qian Zhang
- Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Christoph Loderer
- Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
| | - Cristina Alcántara
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Valencia, Spain
| | - Ariane Müller
- Institut für Zoologie, Technische Universität Dresden, Dresden, Germany
| | - Mohammad Rahnamaeian
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Giessen, Germany
| | - Andreas Vilcinskas
- Fraunhofer Institute for Molecular Biology and Applied Ecology, Department of Bioresources, Giessen, Germany
- Institute for Insect Biotechnology, Justus Liebig University Giessen, Giessen, Germany
| | - Susanne Gebhard
- Department of Biology and Biochemistry, Milner Centre for Evolution, University of Bath, United Kingdom
| | - Manuel Zúñiga
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Valencia, Spain
| | - Thorsten Mascher
- Institut für Mikrobiologie, Technische Universität Dresden, Dresden, Germany
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Systematic engineering of branch chain amino acid supply modules for the enhanced production of bacitracin from Bacillus licheniformis. Metab Eng Commun 2020; 11:e00136. [PMID: 32637317 PMCID: PMC7326738 DOI: 10.1016/j.mec.2020.e00136] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 06/03/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023] Open
Abstract
Bacitracin is a broad-spectrum cyclic peptide antibiotic mainly produced by Bacillus, precursor amino acid supply served as the critical role during its synthesis. In this study, we systematically engineered branch-chain amino acid (BCAA) supply modules for bacitracin production. Firstly, we demonstrated that Ile and Leu acted as limiting precursors for bacitracin synthesis, and that BCAA synthetic pathways were strengthened via simultaneous overexpression of, feedback-resistance acetolactate synthase IlvBNfbr, 2-isopropylmalate synthetase LeuAfbr and BCAA aminotransferase YbgE. Using this approach, bacitracin yield from strain DW-BCAA2 was 892.54 U/mL, an increase of 18.32% compared with that DW2 (754.32 U/mL). Secondly, the BCAA permeases, YvbW and BraB, which have higher affinities for Leu and Ile transportation, respectively, were both identified as BCAA importers, with their overexpression improving intracellular BCAA accumulations and bacitracin yields. Finally, the leucine-responsive family regulator, lrpC was deleted to generate the final strain DW-BCAA6, with intracellular concentrations of Ile, Leu and Val increased by 2.26-, 1.90- and 0.72-fold, respectively. The bacitracin yield from DW-BCAA6 was 1029.83 U/mL, an increase of 36.52%, and is the highest bacitracin yield reported. Equally, concentrations of other byproducts including acetic acid, acetoin and 2,3-butanediol were all reduced. Taken together, we devised an efficient strategy for the enhanced production of bacitracin, and a promising B. licheniformis DW-BCAA6 strain was constructed for industrial production of bacitracin. Enhancing intracellular BCAA accumulations benefited bacitracin synthesis. YvbW and BraB were both identified as BCAA importers in B. licheniformis. Deleting lrp increased brnQ transcription and intracellular BCAA concentrations. Bacitracin yield produced by DW-BCAA6 was the highest currently reported.
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Reverón I, Plaza-Vinuesa L, Santamaría L, Oliveros JC, de las Rivas B, Muñoz R, López de Felipe F. Transcriptomic Evidence of Molecular Mechanisms Underlying the Response of Lactobacillus Plantarum WCFS1 to Hydroxytyrosol. Antioxidants (Basel) 2020; 9:antiox9050442. [PMID: 32443873 PMCID: PMC7278804 DOI: 10.3390/antiox9050442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 01/21/2023] Open
Abstract
This study was aimed to gain new insights into the molecular mechanisms used by Lactobacillus plantarum WCFS1 to respond to hydroxytyrosol (HXT), one of the main and health-relevant plant phenolics present in olive oil. To this goal, whole genome transcriptomic profiling was used to better understand the contribution of differential gene expression in the adaptation to HXT by this microorganism. The transcriptomic profile reveals an HXT-triggered antioxidant response involving genes from the ROS (reactive oxygen species) resistome of L. plantarum, genes coding for H2S-producing enzymes and genes involved in the response to thiol-specific oxidative stress. The expression of a set of genes involved in cell wall biogenesis was also upregulated, indicating that this subcellular compartment was a target of HXT. The expression of several MFS (major facilitator superfamily) efflux systems and ABC-transporters was differentially affected by HXT, probably to control its transport across the membrane. L. plantarum transcriptionally reprogrammed nitrogen metabolism and involved the stringent response (SR) to adapt to HXT, as indicated by the reduced expression of genes involved in cell proliferation or related to the metabolism of (p)ppGpp, the molecule that triggers the SR. Our data have identified, at genome scale, the antimicrobial mechanisms of HXT action as well as molecular mechanisms that potentially enable L. plantarum to cope with the effects of this phenolic compound.
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Affiliation(s)
- Inés Reverón
- Laboratorio de Biotecnología Bacteriana. Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), 28040 Madrid, Spain; (I.R.); (L.P.-V.); (L.S.); (B.d.l.R.); (R.M.)
| | - Laura Plaza-Vinuesa
- Laboratorio de Biotecnología Bacteriana. Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), 28040 Madrid, Spain; (I.R.); (L.P.-V.); (L.S.); (B.d.l.R.); (R.M.)
| | - Laura Santamaría
- Laboratorio de Biotecnología Bacteriana. Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), 28040 Madrid, Spain; (I.R.); (L.P.-V.); (L.S.); (B.d.l.R.); (R.M.)
| | | | - Blanca de las Rivas
- Laboratorio de Biotecnología Bacteriana. Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), 28040 Madrid, Spain; (I.R.); (L.P.-V.); (L.S.); (B.d.l.R.); (R.M.)
| | - Rosario Muñoz
- Laboratorio de Biotecnología Bacteriana. Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), 28040 Madrid, Spain; (I.R.); (L.P.-V.); (L.S.); (B.d.l.R.); (R.M.)
| | - Félix López de Felipe
- Laboratorio de Biotecnología Bacteriana. Instituto de Ciencia y Tecnología de los Alimentos y Nutrición (ICTAN-CSIC), 28040 Madrid, Spain; (I.R.); (L.P.-V.); (L.S.); (B.d.l.R.); (R.M.)
- Correspondence: ; Fax: +34-91-549-36-27
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Cai D, Zhang B, Zhu J, Xu H, Liu P, Wang Z, Li J, Yang Z, Ma X, Chen S. Enhanced Bacitracin Production by Systematically Engineering S-Adenosylmethionine Supply Modules in Bacillus licheniformis. Front Bioeng Biotechnol 2020; 8:305. [PMID: 32318565 PMCID: PMC7155746 DOI: 10.3389/fbioe.2020.00305] [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: 02/04/2020] [Accepted: 03/20/2020] [Indexed: 12/11/2022] Open
Abstract
Bacitracin is a broad-spectrum veterinary antibiotic that widely used in the fields of veterinary drug and feed additive. S-Adenosylmethionine (SAM) is a critical factor involved in many biochemical reactions, especially antibiotic production. However, whether SAM affects bacitracin synthesis is still unknown. Here, we want to analyze the relationship between SAM supply and bacitracin synthesis, and then metabolic engineering of SAM synthetic pathway for bacitracin production in Bacillus licheniformis. Firstly, our results implied that SAM exogenous addition benefited bacitracin production, which yield was increased by 12.13% under the condition of 40 mg/L SAM addition. Then, SAM synthetases and Methionine (Met) synthetases from B. licheniformis, Corynebacterium glutamicum, and Saccharomyces cerevisiae were screened and overexpressed to improve SAM accumulation, and the combination of SAM synthetase from S. cerevisiae and Met synthetase from B. licheniformis showed the best performance, and 70.12% increase of intracellular SAM concentration (31.54 mg/L) and 13.08% increase of bacitraicn yield (839.54 U/mL) were achieved in resultant strain DW2-KE. Furthermore, Met transporters MetN and MetP were, respectively, identified as Met exporter and importer, and bacitracin yield was further increased by 5.94% to 889.42 U/mL via deleting metN and overexpressing metP in DW2-KE, attaining strain DW2-KENP. Finally, SAM nucleosidase gene mtnN and SAM decarboxylase gene speD were deleted to block SAM degradation pathways, and bacitracin yield of resultant strain DW2-KENPND reached 957.53 U/mL, increased by 28.97% compared to DW2. Collectively, this study demonstrated that SAM supply served as the critical role in bacitracin synthesis, and a promising strain B. licheniformis DW2-KENPND was attained for industrial production of bacitracin.
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Affiliation(s)
- Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Bowen Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Jiang Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Haixia Xu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Pei Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Zhi Wang
- Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Key Laboratory of Industrial Microbiology, School of Food and Biological Engineering, Hubei University of Technology, Wuhan, China
| | - Junhui Li
- Lifecome Biochemistry Co., Ltd., Nanping, China
| | - Zhifan Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Xin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, China
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Baindara P, Ghosh AK, Mandal SM. Coevolution of Resistance Against Antimicrobial Peptides. Microb Drug Resist 2020; 26:880-899. [PMID: 32119634 DOI: 10.1089/mdr.2019.0291] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Antimicrobial peptides (AMPs) are produced by all forms of life, ranging from eukaryotes to prokaryotes, and they are a crucial component of innate immunity, involved in clearing infection by inhibiting pathogen colonization. In the recent past, AMPs received high attention due to the increase of extensive antibiotic resistance by these pathogens. AMPs exhibit a diverse spectrum of activity against bacteria, fungi, parasites, and various types of cancer. AMPs are active against various bacterial pathogens that cause disease in animals and plants. However, because of the coevolution of host and pathogen interaction, bacteria have developed the mechanisms to sense and exhibit an adaptive response against AMPs. These resistance mechanisms are playing an important role in bacterial virulence within the host. Here, we have discussed the different resistance mechanisms used by gram-positive and gram-negative bacteria to sense and combat AMP actions. Understanding the mechanism of AMP resistance may provide directions toward the development of novel therapeutic strategies to control multidrug-resistant pathogens.
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Affiliation(s)
- Piyush Baindara
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Ananta K Ghosh
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - Santi M Mandal
- Department of Biotechnology, Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, India
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BceAB-Type Antibiotic Resistance Transporters Appear To Act by Target Protection of Cell Wall Synthesis. Antimicrob Agents Chemother 2020; 64:AAC.02241-19. [PMID: 31871088 PMCID: PMC7038271 DOI: 10.1128/aac.02241-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 12/18/2019] [Indexed: 11/25/2022] Open
Abstract
Resistance against cell wall-active antimicrobial peptides in bacteria is often mediated by transporters. In low-GC-content Gram-positive bacteria, a common type of such transporters is BceAB-like systems, which frequently provide high-level resistance against peptide antibiotics that target intermediates of the lipid II cycle of cell wall synthesis. How a transporter can offer protection from drugs that are active on the cell surface, however, has presented researchers with a conundrum. Resistance against cell wall-active antimicrobial peptides in bacteria is often mediated by transporters. In low-GC-content Gram-positive bacteria, a common type of such transporters is BceAB-like systems, which frequently provide high-level resistance against peptide antibiotics that target intermediates of the lipid II cycle of cell wall synthesis. How a transporter can offer protection from drugs that are active on the cell surface, however, has presented researchers with a conundrum. Multiple theories have been discussed, ranging from removal of the peptides from the membrane and internalization of the drug for degradation to removal of the cellular target rather than the drug itself. To resolve this much-debated question, we here investigated the mode of action of the transporter BceAB of Bacillus subtilis. We show that it does not inactivate or import its substrate antibiotic bacitracin. Moreover, we present evidence that the critical factor driving transport activity is not the drug itself but instead the concentration of drug-target complexes in the cell. Our results, together with previously reported findings, lead us to propose that BceAB-type transporters act by transiently freeing lipid II cycle intermediates from the inhibitory grip of antimicrobial peptides and thus provide resistance through target protection of cell wall synthesis. Target protection has so far only been reported for resistance against antibiotics with intracellular targets, such as the ribosome. However, this mechanism offers a plausible explanation for the use of transporters as resistance determinants against cell wall-active antibiotics in Gram-positive bacteria where cell wall synthesis lacks the additional protection of an outer membrane.
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Popp PF, Benjdia A, Strahl H, Berteau O, Mascher T. The Epipeptide YydF Intrinsically Triggers the Cell Envelope Stress Response of Bacillus subtilis and Causes Severe Membrane Perturbations. Front Microbiol 2020; 11:151. [PMID: 32117169 PMCID: PMC7026026 DOI: 10.3389/fmicb.2020.00151] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/22/2020] [Indexed: 01/05/2023] Open
Abstract
The Gram-positive model organism and soil bacterium Bacillus subtilis naturally produces a variety of antimicrobial peptides (AMPs), including the ribosomally synthesized and post-translationally modified AMP YydF, which is encoded in the yydFGHIJ locus. The yydF gene encodes the pre-pro-peptide, which is, in a unique manner, initially modified at two amino acid positions by the radical SAM epimerase YydG. Subsequently, the membrane-anchored putative protease YydH is thought to cleave and release the mature AMP, YydF, to the environment. The AMP YydF, with two discreet epimerizations among 17 residues as sole post-translational modification, defines a novel class of ribosomally synthesized and post-translationally modified peptides (RiPPs) called epipeptides, for which the mode-of-action (MOA) is unknown. The predicted ABC transporter encoded by yydIJ was previously postulated as an autoimmunity determinant of B. subtilis against its own AMP. Here, we demonstrate that extrinsically added YydF* kills B. subtilis cells by dissipating membrane potential via membrane permeabilization. This severe membrane perturbation is accompanied by a rapid reduction of membrane fluidity, substantiated by lipid domain formation. The epipeptide triggers a narrow and highly specific cellular response. The strong induction of liaIH expression, a marker for cell envelope stress in B. subtilis, further supports the MOA described above. A subsequent mutational study demonstrates that LiaIH—and not YydIJ—represents the most efficient resistance determinant against YydF* action. Unexpectedly, none of the observed cellular effects upon YydF* treatment alone are able to trigger liaIH expression, indicating that only the unique combination of membrane permeabilization and membrane rigidification caused by the epipetide, leads to the observed cell envelope stress response.
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Affiliation(s)
- Philipp F Popp
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
| | - Alhosna Benjdia
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Henrik Strahl
- Center for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Olivier Berteau
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, ChemSyBio, Jouy-en-Josas, France
| | - Thorsten Mascher
- Institute of Microbiology, Technische Universität (TU) Dresden, Dresden, Germany
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From Modules to Networks: a Systems-Level Analysis of the Bacitracin Stress Response in Bacillus subtilis. mSystems 2020; 5:5/1/e00687-19. [PMID: 32019833 PMCID: PMC7002115 DOI: 10.1128/msystems.00687-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Antibiotic resistance poses a major threat to global health, and systematic studies to understand the underlying resistance mechanisms are urgently needed. Although significant progress has been made in deciphering the mechanistic basis of individual resistance determinants, many bacterial species rely on the induction of a whole battery of resistance modules, and the complex regulatory networks controlling these modules in response to antibiotic stress are often poorly understood. In this work we combined experiments and theoretical modeling to decipher the resistance network of Bacillus subtilis against bacitracin, which inhibits cell wall biosynthesis in Gram-positive bacteria. We found a high level of cross-regulation between the two major resistance modules in response to bacitracin stress and quantified their effects on bacterial resistance. To rationalize our experimental data, we expanded a previously established computational model for the lipid II cycle through incorporating the quantitative action of the resistance modules. This led us to a systems-level description of the bacitracin stress response network that captures the complex interplay between resistance modules and the essential lipid II cycle of cell wall biosynthesis and accurately predicts the minimal inhibitory bacitracin concentration in all the studied mutants. With this, our study highlights how bacterial resistance emerges from an interlaced network of redundant homeostasis and stress response modules. Bacterial resistance against antibiotics often involves multiple mechanisms that are interconnected to ensure robust protection. So far, the knowledge about underlying regulatory features of those resistance networks is sparse, since they can hardly be determined by experimentation alone. Here, we present the first computational approach to elucidate the interplay between multiple resistance modules against a single antibiotic and how regulatory network structure allows the cell to respond to and compensate for perturbations of resistance. Based on the response of Bacillus subtilis toward the cell wall synthesis-inhibiting antibiotic bacitracin, we developed a mathematical model that comprehensively describes the protective effect of two well-studied resistance modules (BceAB and BcrC) on the progression of the lipid II cycle. By integrating experimental measurements of expression levels, the model accurately predicts the efficacy of bacitracin against the B. subtilis wild type as well as mutant strains lacking one or both of the resistance modules. Our study reveals that bacitracin-induced changes in the properties of the lipid II cycle itself control the interplay between the two resistance modules. In particular, variations in the concentrations of UPP, the lipid II cycle intermediate that is targeted by bacitracin, connect the effect of the BceAB transporter and the homeostatic response via BcrC to an overall resistance response. We propose that monitoring changes in pathway properties caused by a stressor allows the cell to fine-tune deployment of multiple resistance systems and may serve as a cost-beneficial strategy to control the overall response toward this stressor. IMPORTANCE Antibiotic resistance poses a major threat to global health, and systematic studies to understand the underlying resistance mechanisms are urgently needed. Although significant progress has been made in deciphering the mechanistic basis of individual resistance determinants, many bacterial species rely on the induction of a whole battery of resistance modules, and the complex regulatory networks controlling these modules in response to antibiotic stress are often poorly understood. In this work we combined experiments and theoretical modeling to decipher the resistance network of Bacillus subtilis against bacitracin, which inhibits cell wall biosynthesis in Gram-positive bacteria. We found a high level of cross-regulation between the two major resistance modules in response to bacitracin stress and quantified their effects on bacterial resistance. To rationalize our experimental data, we expanded a previously established computational model for the lipid II cycle through incorporating the quantitative action of the resistance modules. This led us to a systems-level description of the bacitracin stress response network that captures the complex interplay between resistance modules and the essential lipid II cycle of cell wall biosynthesis and accurately predicts the minimal inhibitory bacitracin concentration in all the studied mutants. With this, our study highlights how bacterial resistance emerges from an interlaced network of redundant homeostasis and stress response modules.
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Sandiford SK. An overview of lantibiotic biosynthetic machinery promiscuity and its impact on antimicrobial discovery. Expert Opin Drug Discov 2020; 15:373-382. [PMID: 31941374 DOI: 10.1080/17460441.2020.1699530] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Introduction: The continued emergence of drug resistant bacteria within the nosocomial and community environment recalcitrant to conventional antimicrobial therapies has enforced the requirement for novel therapeutics. This has led to a renewed interest in peptide antimicrobials, including ribosomally synthesized peptides termed lantibiotics. Lantibiotics represent a novel class of agents that many studies have highlighted as effective against a range of pathogenic bacteria.Areas covered: In this review, the modular nature of lantibiotic synthesis is discussed and how this can be exploited not only to improve known lantibiotics but also for the creation of new to nature lantibiotics exhibiting improved pharmacological properties, antimicrobial activity and ability to bypass bacterial resistance mechanisms.Expert opinion: The use of combinatorial biosynthetic systems to combine different modules or ring structures of known lantibiotics have also been utilized to create new to nature lantibiotics. To fully exploit the available information and its application to lantibiotic engineering, additional structure activity relationship (SAR) analysis is required to fully understand the impact of certain post-translational modifications and the impact they have upon the activity, stability and pharmacological properties.
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Ahmad A, Majaz S, Nouroz F. Two-component systems regulate ABC transporters in antimicrobial peptide production, immunity and resistance. Microbiology (Reading) 2020; 166:4-20. [DOI: 10.1099/mic.0.000823] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bacteria offer resistance to a broad range of antibiotics by activating their export channels of ATP-binding cassette transporters. These transporters perform a central role in vital processes of self-immunity, antibiotic transport and resistance. The majority of ATP-binding cassette transporters are capable of detecting the presence of antibiotics in an external vicinity and are tightly regulated by two-component systems. The presence of an extracellular loop and an adjacent location of both the transporter and two-component system offers serious assistance to induce a quick and specific response against antibiotics. Both systems have demonstrated their ability of sensing such agents, however, the exact mechanism is not yet fully established. This review highlighted the three key functions of antibiotic resistance, transport and self-immunity of ATP-binding cassette transporters and an adjacent two-component regulatory system.
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Affiliation(s)
- Ashfaq Ahmad
- Department of Bioinformatics, Hazara University, Mansehra, KPK, Pakistan
| | - Sidra Majaz
- Department of Bioinformatics, Hazara University, Mansehra, KPK, Pakistan
| | - Faisal Nouroz
- Department of Bioinformatics, Hazara University, Mansehra, KPK, Pakistan
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The VirAB-VirSR-AnrAB Multicomponent System Is Involved in Resistance of Listeria monocytogenes EGD-e to Cephalosporins, Bacitracin, Nisin, Benzalkonium Chloride, and Ethidium Bromide. Appl Environ Microbiol 2019; 85:AEM.01470-19. [PMID: 31399408 DOI: 10.1128/aem.01470-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
In Listeria monocytogenes, it has been proposed that the VirSR two-component signal transduction systems (TCSs) and two ATP-binding cassette (ABC) transporters, VirAB and AnrAB, constitute a complex TCS/ABC transporter system which has been recognized as a unique resistance mode. The role of the putative VirAB-VirSR-AnrAB system in antimicrobial resistance and the respective contributions of the members of the system to resistance were investigated in this study. We constructed gene deletion mutants of L. monocytogenes EGD-e and complemented strains of the mutants and determined MICs of antimicrobial agents against these strains against using the agar dilution method. We assessed the relative expression levels of target genes by reverse transcription-quantitative PCR (RT-qPCR) and measured promoter activity levels by β-galactosidase assays. Our results showed that the VirAB-VirSR-AnrAB system mediates not only nisin and bacitracin resistance but also resistance to cephalosporins, ethidium bromide (EtBr), and benzalkonium chloride (BC). In this system, two ABC transporters, VirAB and AnrAB, play distinct roles in cefotaxime resistance: the former is responsible only for antimicrobial sensing and signaling by VirSR, while the latter contributes to transportation of antimicrobials. Notably, VirAB itself, rather than the VirAB-VirSR-AnrAB system as a whole, contributes to kanamycin and tetracycline resistance. On the basis of the results obtained from this study, we speculate that VirAB acts as a sensor for VirSR in response to cephalosporins, bacitracin, nisin, EtBr, and BC, while VirAB itself plays a role in response to kanamycin and tetracycline in L. monocytogenes EGD-e.IMPORTANCE This report describes TCS/ABC transporter modules characterized in Listeria monocytogenes EGD-e. The modules consist of the VirSR TCS and the VirAB and AnrAB ABC transporters. Our results showed that this system is involved in nisin and bacitracin resistance, as well as resistance to cephalosporins, ethidium bromide (EtBr), and benzalkonium chloride (BC). In this system, VirAB is responsible only for antimicrobial sensing and signaling by VirSR, while AnrAB contributes to transportation of antimicrobials. Interestingly, VirAB itself, rather than the VirAB-VirSR-AnrAB system as a whole, contributes to kanamycin and tetracycline resistance.
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Geiger C, Korn SM, Häsler M, Peetz O, Martin J, Kötter P, Morgner N, Entian KD. LanI-Mediated Lantibiotic Immunity in Bacillus subtilis: Functional Analysis. Appl Environ Microbiol 2019; 85:e00534-19. [PMID: 30952662 PMCID: PMC6532034 DOI: 10.1128/aem.00534-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 03/26/2019] [Indexed: 01/09/2023] Open
Abstract
Lantibiotics subtilin and nisin are produced by Bacillus subtilis and Lactococcus lactis, respectively. To prevent toxicity of their own lantibiotic, both bacteria express specific immunity proteins, called SpaI and NisI. In addition, ABC transporters SpaFEG and NisFEG prevent lantibiotic toxicity by transporting the respective peptides to the extracellular space. Although the three-dimensional structures of SpaI and NisI have been solved, very little is known about the molecular function of either lipoprotein. Using laser-induced liquid bead ion desorption (LILBID)-mass spectrometry, we show here that subtilin interacts with SpaI monomers. The expression of either SpaI or NisI in a subtilin-nonproducing B. subtilis strain resulted in the respective strain being more resistant against either subtilin or nisin. Furthermore, pore formation provided by subtilin and nisin was prevented specifically upon the expression of either SpaI or NisI. As shown with a nisin-subtilin hybrid molecule, the C-terminal part of subtilin but not any particular lanthionine ring was needed for SpaI-mediated immunity. With respect to growth, SpaI provided less immunity against subtilin than is provided by the ABC transporter SpaFEG. However, SpaI prevented pore formation much more efficiently than SpaFEG. Taken together, our data show the physiological function of SpaI as a fast immune response to protect the cellular membrane.IMPORTANCE The two lantibiotics nisin and subtilin are produced by Lactococcus lactis and Bacillus subtilis, respectively. Both peptides have strong antimicrobial activity against Gram-positive bacteria, and therefore, appropriate protection mechanisms are required for the producing strains. To prevent toxicity of their own lantibiotic, both bacteria express immunity proteins, called SpaI and NisI, and in addition, ABC transporters SpaFEG and NisFEG. Whereas it has been shown that the ABC transporters protect the producing strains by transporting the toxic peptides to the extracellular space, the exact mode of action and the physiological function of the lipoproteins during immunity are still unknown. Understanding the exact role of lantibiotic immunity proteins is of major importance for improving production rates and for the design of newly engineered peptide antibiotics. Here, we show (i) the specificity of each lipoprotein for its own lantibiotic, (ii) the specific physical interaction of subtilin with its lipoprotein SpaI, (iii) the physiological function of SpaI in protecting the cellular membrane, and (iv) the importance of the C-terminal part of subtilin for its interaction with SpaI.
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Affiliation(s)
- Christoph Geiger
- Molecular Genetics and Cellular Microbiology, Institute for Molecular Biosciences, University of Frankfurt, Frankfurt, Germany
| | - Sophie Marianne Korn
- Molecular Genetics and Cellular Microbiology, Institute for Molecular Biosciences, University of Frankfurt, Frankfurt, Germany
| | - Michael Häsler
- Molecular Genetics and Cellular Microbiology, Institute for Molecular Biosciences, University of Frankfurt, Frankfurt, Germany
| | - Oliver Peetz
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt, Germany
| | - Janosch Martin
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt, Germany
| | - Peter Kötter
- Molecular Genetics and Cellular Microbiology, Institute for Molecular Biosciences, University of Frankfurt, Frankfurt, Germany
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry, Goethe University, Frankfurt, Germany
| | - Karl-Dieter Entian
- Molecular Genetics and Cellular Microbiology, Institute for Molecular Biosciences, University of Frankfurt, Frankfurt, Germany
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Tierney AR, Rather PN. Roles of two-component regulatory systems in antibiotic resistance. Future Microbiol 2019; 14:533-552. [PMID: 31066586 DOI: 10.2217/fmb-2019-0002] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Two-component regulatory systems (TCSs) are a major mechanism by which bacteria sense and respond to changes in their environment. TCSs typically consist of two proteins that bring about major regulation of the cell genome through coordinated action mediated by phosphorylation. Environmental conditions that activate TCSs are numerous and diverse and include exposure to antibiotics as well as conditions inside a host. The resulting regulatory action often involves activation of antibiotic defenses and changes to cell physiology that increase antibiotic resistance. Examples of resistance mechanisms enacted by TCSs contained in this review span those found in both Gram-negative and Gram-positive species and include cell surface modifications, changes in cell permeability, increased biofilm formation, and upregulation of antibiotic-degrading enzymes.
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Affiliation(s)
- Aimee Rp Tierney
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, GA, 30322 USA
| | - Philip N Rather
- Department of Microbiology & Immunology, Emory University School of Medicine, Atlanta, GA, 30322 USA.,Research Service, Department of Veterans' Affairs, Atlanta VA Health Care System, Decatur, GA, 30033 USA
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Darnell RL, Nakatani Y, Knottenbelt MK, Gebhard S, Cook GM. Functional characterization of BcrR: a one-component transmembrane signal transduction system for bacitracin resistance. MICROBIOLOGY-SGM 2019; 165:475-487. [PMID: 30777814 DOI: 10.1099/mic.0.000781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacitracin is a cell wall targeting antimicrobial with clinical and agricultural applications. With the growing mismatch between antimicrobial resistance and development, it is essential we understand the molecular mechanisms of resistance in order to prioritize and generate new effective antimicrobials. BcrR is a unique membrane-bound one-component system that regulates high-level bacitracin resistance in Enterococcus faecalis. In the presence of bacitracin, BcrR activates transcription of the bcrABD operon conferring resistance through a putative ATP-binding cassette (ABC) transporter (BcrAB). BcrR has three putative functional domains, an N-terminal helix-turn-helix DNA-binding domain, an intermediate oligomerization domain and a C-terminal transmembrane domain. However, the molecular mechanisms of signal transduction remain unknown. Random mutagenesis of bcrR was performed to generate loss- and gain-of-function mutants using transcriptional reporters fused to the target promoter PbcrA. Fifteen unique mutants were isolated across all three proposed functional domains, comprising 14 loss-of-function and one gain-of-function mutant. The gain-of-function variant (G64D) mapped to the putative dimerization domain of BcrR, and functional analyses indicated that the G64D mutant constitutively expresses the PbcrA-luxABCDE reporter. DNA-binding and membrane insertion were not affected in the five mutants chosen for further characterization. Homology modelling revealed putative roles for two key residues (R11 and S33) in BcrR activation. Here we present a new model of BcrR activation and signal transduction, providing valuable insight into the functional characterization of membrane-bound one-component systems and how they can coordinate critical bacterial responses, such as antimicrobial resistance.
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Affiliation(s)
- Rachel L Darnell
- 1Department of Microbiology and Immunology, University of Otago, Dunedin, New zealand.,2Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Yoshio Nakatani
- 1Department of Microbiology and Immunology, University of Otago, Dunedin, New zealand.,2Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Melanie K Knottenbelt
- 1Department of Microbiology and Immunology, University of Otago, Dunedin, New zealand
| | - Susanne Gebhard
- 3Milner Centre for Evolution, Department of Biology and Biochemistry, University of Bath, Bath, UK
| | - Gregory M Cook
- 2Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1042, New Zealand.,1Department of Microbiology and Immunology, University of Otago, Dunedin, New zealand
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Vadakedath N, Halami PM. Characterization and mode of action of a potent bio-preservative from food-gradeBacillus licheniformisMCC 2016. Prep Biochem Biotechnol 2019; 49:334-343. [DOI: 10.1080/10826068.2019.1566141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Nithya Vadakedath
- Department of Microbiology and Fermentation Technology, CSIR-Central Food Technological Research Institute, Mysore, India
| | - Prakash M. Halami
- Department of Microbiology and Fermentation Technology, CSIR-Central Food Technological Research Institute, Mysore, India
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Acquired Nisin Resistance in Staphylococcus aureus Involves Constitutive Activation of an Intrinsic Peptide Antibiotic Detoxification Module. mSphere 2018; 3:3/6/e00633-18. [PMID: 30541781 PMCID: PMC6291627 DOI: 10.1128/mspheredirect.00633-18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
NIS and related bacteriocins are of interest as candidates for the treatment of human infections caused by Gram-positive pathogens such as Staphylococcus aureus. An important liability of NIS in this regard is the ease with which S. aureus acquires resistance. Here we establish that this organism naturally possesses the cellular machinery to detoxify NIS but that the ABC transporter responsible (VraDE) is not ordinarily produced to a degree sufficient to yield substantial resistance. Acquired NIS resistance mutations prompt activation of the regulatory circuit controlling expression of vraDE, thereby unmasking an intrinsic resistance determinant. Our results provide new insights into the complex mechanism by which expression of vraDE is regulated and suggest that a potential route to overcoming the resistance liability of NIS could involve chemical modification of the molecule to prevent its recognition by the VraDE transporter. Resistance to the lantibiotic nisin (NIS) arises readily in Staphylococcus aureus as a consequence of mutations in the nsaS gene, which encodes the sensor kinase of the NsaRS two-component regulatory system. Here we present a series of studies to establish how these mutational changes result in reduced NIS susceptibility. Comparative transcriptomic analysis revealed upregulation of the NsaRS regulon in a NIS-resistant mutant of S. aureus versus its otherwise-isogenic progenitor, indicating that NIS resistance mutations prompt gain-of-function in NsaS. Two putative ABC transporters (BraDE and VraDE) encoded within the NsaRS regulon that have been reported to provide a degree of intrinsic protection against NIS were shown to be responsible for acquired NIS resistance; as is the case for intrinsic NIS resistance, NIS detoxification was ultimately mediated by VraDE, with BraDE participating in the signaling cascade underlying VraDE expression. Our study revealed new features of this signal transduction pathway, including that BraDE (but not VraDE) physically interacts with NsaRS. Furthermore, while BraDE has been shown to sense stimuli and signal to NsaS in a process that is contingent upon ATP hydrolysis, we established that this protein complex is also essential for onward transduction of the signal from NsaS through energy-independent means. NIS resistance in S. aureus therefore joins the small number of documented examples in which acquired antimicrobial resistance results from the unmasking of an intrinsic detoxification mechanism through gain-of-function mutation in a regulatory circuit. IMPORTANCE NIS and related bacteriocins are of interest as candidates for the treatment of human infections caused by Gram-positive pathogens such as Staphylococcus aureus. An important liability of NIS in this regard is the ease with which S. aureus acquires resistance. Here we establish that this organism naturally possesses the cellular machinery to detoxify NIS but that the ABC transporter responsible (VraDE) is not ordinarily produced to a degree sufficient to yield substantial resistance. Acquired NIS resistance mutations prompt activation of the regulatory circuit controlling expression of vraDE, thereby unmasking an intrinsic resistance determinant. Our results provide new insights into the complex mechanism by which expression of vraDE is regulated and suggest that a potential route to overcoming the resistance liability of NIS could involve chemical modification of the molecule to prevent its recognition by the VraDE transporter.
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