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Bonini D, Duggan S, Alnahari A, Brignoli T, Strahl H, Massey RC. Lipoteichoic acid biosynthesis by Staphylococcus aureus is controlled by the MspA protein. mBio 2024; 15:e0151224. [PMID: 39037275 PMCID: PMC11323550 DOI: 10.1128/mbio.01512-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 06/30/2024] [Indexed: 07/23/2024] Open
Abstract
Staphylococcus aureus produces a plethora of virulence factors critical to its ability to establish an infection and cause disease. We have previously characterized a small membrane protein, MspA, which has pleiotropic effects on virulence and contributes to S. aureus pathogenicity in vivo. Here we report that mspA inactivation triggers overaccumulation of the essential cell wall component, lipoteichoic acid (LTA), which, in turn, decreases autolytic activity and leads to increased cell size due to a delay in cell separation. We show that MspA directly interacts with the enzymes involved in LTA biosynthesis (LtaA, LtaS, UgtP, and SpsB), interfering with their normal activities. MspA, in particular, interacts with the type I signal peptidase SpsB, limiting its cleavage of LtaS into its active form. These findings suggest that MspA contributes to maintaining a physiological level of LTA in the cell wall by interacting with and inhibiting the activity of SpsB, thereby uncovering a critical role for the MspA protein in regulating cell envelope biosynthesis and pathogenicity.IMPORTANCEThe S. aureus cell envelope, comprising the cytoplasmic membrane, a thick peptidoglycan layer, and the anionic polymers lipoteichoic acid and wall teichoic acids, is fundamental for bacterial growth and division, as well as being the main interface between the pathogen and the host. It has become increasingly apparent that the synthesis and turnover of cell envelope components also affect the virulence of S. aureus. In this study, we show that MspA, an effector of S. aureus virulence, contributes to the maintenance of normal levels of lipoteichoic acid in the cell wall, with implications on cell cycle and size. These findings further our understanding of the connections between envelope synthesis and pathogenicity and suggest that MspA represents a promising target for the development of future therapeutic strategies.
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Affiliation(s)
- Dora Bonini
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Seána Duggan
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Alaa Alnahari
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- Department of Biological Sciences, University of Jeddah, Jeddah, Saudi Arabia
| | - Tarcisio Brignoli
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- Department of Biosciences, Università degli Studi di Milano, Milan, Italy
| | - Henrik Strahl
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Ruth C. Massey
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
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Hollwedel FD, Maus R, Stolper J, Iwai S, Kasai H, Holtfreter S, Pich A, Neubert L, Welte T, Yamasaki S, Maus UA. Ectopic Expression of C-Type Lectin Mincle Renders Mice Susceptible to Staphylococcal Pneumonia. J Infect Dis 2024; 230:198-208. [PMID: 39052710 DOI: 10.1093/infdis/jiad608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 12/05/2023] [Accepted: 12/29/2023] [Indexed: 01/03/2024] Open
Abstract
Staphylococcus aureus is a prevalent pathogen in pneumonia and harbors glycolipids, which may serve as molecular patterns in Mincle (macrophage-inducible C-type lectin)-dependent pathogen recognition. We examined the role of Mincle in lung defense against S aureus in wild-type (WT), Mincle knockout (KO), and Mincle transgenic (tg) mice. Two glycolipids, glucosyl-diacylglycerol (Glc-DAG) and diglucosyl-diacylglycerol (Glc2-DAG), were purified, of which only Glc-DAG triggered Mincle reporter cell activation and professional phagocyte responses. Proteomic profiling revealed that Glc2-DAG blocked Glc-DAG-induced cytokine responses, thereby acting as inhibitor of Glc-DAG/Mincle signaling. WT mice responded to S aureus with a similar lung pathology as Mincle KO mice, most likely due to Glc2-DAG-dependent inhibition of Glc-DAG/Mincle signaling. In contrast, ectopic Mincle expression caused severe lung pathology in S aureus-infected mice, characterized by bacterial outgrowth and fatal pneumonia. Collectively, Glc2-DAG inhibits Glc-DAG/Mincle-dependent responses in WT mice, whereas sustained Mincle expression overrides Glc2-DAG-mediated inhibitory effects, conferring increased host susceptibility to S aureus.
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Affiliation(s)
- Femke D Hollwedel
- Division of Experimental Pneumology, Hannover Medical School, Hannover, Germany
| | - Regina Maus
- Division of Experimental Pneumology, Hannover Medical School, Hannover, Germany
| | - Jennifer Stolper
- Division of Experimental Pneumology, Hannover Medical School, Hannover, Germany
| | - Satoru Iwai
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Hayato Kasai
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Silva Holtfreter
- Institute of Immunology, University Medicine Greifswald, Greifswald, Germany
| | - Andreas Pich
- Institute of Toxicology and Core Facility Proteomics, Hannover Medical School, Hannover, Germany
| | - Lavinia Neubert
- Institute of Pathology, Hannover Medical School, Hannover, Germany
| | - Tobias Welte
- Clinic for Pneumology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, partner site BREATH, Hannover, Germany
| | - Sho Yamasaki
- Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Ulrich A Maus
- Division of Experimental Pneumology, Hannover Medical School, Hannover, Germany
- German Center for Lung Research, partner site BREATH, Hannover, Germany
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Schürmann J, Fischer MA, Herzberg M, Reemtsma T, Strommenger B, Werner G, Schuster CF, Layer-Nicolaou F. The genes mgtE and spoVG are involved in zinc tolerance of Staphylococcus aureus. Appl Environ Microbiol 2024; 90:e0045324. [PMID: 38752746 PMCID: PMC11218649 DOI: 10.1128/aem.00453-24] [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: 03/15/2024] [Accepted: 04/16/2024] [Indexed: 06/19/2024] Open
Abstract
Metals are essential for all living organisms, but the type of metal and its concentration determines its action. Even low concentrations of metals may have toxic effects on organisms and therefore exhibit antimicrobial activities. In this study, we investigate the evolutionary adaptation processes of Staphylococcus aureus to metals and common genes for metal tolerance. Laboratory and clinical isolates were treated with manganese, cobalt, zinc, or nickel metal salts to generate growth-adapted mutants. After growth in medium supplemented with zinc, whole-genome sequencing identified, among others, two genes, mgtE (SAUSA300_0910), a putative magnesium transporter and spoVG (SAUSA300_0475), a global transcriptional regulator, as hot spots for stress-induced single-nucleotide polymorphisms (SNPs). SNPs in mgtE were also detected in mutants treated with high levels of cobalt or nickel salts. To investigate the effect of these genes on metal tolerance, deletion mutants and complementation strains in an S. aureus USA300 LAC* laboratory strain were generated. Both, the mgtE and spoVG deletion strains were more tolerant to cobalt, manganese, and zinc. The mgtE mutant was also more tolerant to nickel exposure. Inductively coupled plasma mass spectrometry analysis demonstrated that the mgtE deletion mutant accumulated less intracellular zinc than the wild type, explaining increased tolerance. From these results, we conclude that mgtE gene inactivation increases zinc tolerance presumably due to reduced uptake of zinc. For the SpoVG mutant, no direct effect on the intracellular zinc concentration was detected, indicating toward different pathways to increase tolerance. Importantly, inactivation of these genes offers a growth advantage in environments containing certain metals, pointing toward a common tolerance mechanism. IMPORTANCE Staphylococcus aureus is an opportunistic pathogen causing tremendous public health burden and high mortality in invasive infections. Treatment is becoming increasingly difficult due to antimicrobial resistances. The use of metals in animal husbandry and aquaculture to reduce bacterial growth and subsequent acquisition of metal resistances has been shown to co-select for antimicrobial resistance. Therefore, understanding adaptive mechanisms that help S. aureus to survive metal exposure is essential. Using a screening approach, we were able to identify two genes encoding the transporter MgtE and the transcriptional regulator SpoVG, which conferred increased tolerance to specific metals such as zinc when inactivated. Further testing showed that the deletion of mgtE leads to reduced intracellular zinc levels, suggesting a role in zinc uptake. The accumulation of mutations in these genes when exposed to other metals suggests that inactivation of these genes could be a common mechanism for intrinsic tolerance to certain metals.
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Affiliation(s)
- Jacqueline Schürmann
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Martin A. Fischer
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Martin Herzberg
- Department Environmental Analytical Chemistry, Helmholtz-Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Thorsten Reemtsma
- Department Environmental Analytical Chemistry, Helmholtz-Centre for Environmental Research – UFZ, Leipzig, Germany
| | - Birgit Strommenger
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Guido Werner
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Christopher F. Schuster
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Franziska Layer-Nicolaou
- Department of Infectious Diseases, Division of Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
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Barbuti MD, Lambert E, Myrbråten IS, Ducret A, Stamsås GA, Wilhelm L, Liu X, Salehian Z, Veening JW, Straume D, Grangeasse C, Perez C, Kjos M. The function of CozE proteins is linked to lipoteichoic acid biosynthesis in Staphylococcus aureus. mBio 2024; 15:e0115724. [PMID: 38757970 PMCID: PMC11237490 DOI: 10.1128/mbio.01157-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 04/21/2024] [Indexed: 05/18/2024] Open
Abstract
Coordinated membrane and cell wall synthesis is vital for maintaining cell integrity and facilitating cell division in bacteria. However, the molecular mechanisms that underpin such coordination are poorly understood. Here we uncover the pivotal roles of the staphylococcal proteins CozEa and CozEb, members of a conserved family of membrane proteins previously implicated in bacterial cell division, in the biosynthesis of lipoteichoic acids (LTA) and maintenance of membrane homeostasis in Staphylococcus aureus. We establish that there is a synthetic lethal relationship between CozE and UgtP, the enzyme synthesizing the LTA glycolipid anchor Glc2DAG. By contrast, in cells lacking LtaA, the flippase of Glc2DAG, the essentiality of CozE proteins was alleviated, suggesting that the function of CozE proteins is linked to the synthesis and flipping of the glycolipid anchor. CozE proteins were indeed found to modulate the flipping activity of LtaA in vitro. Furthermore, CozEb was shown to control LTA polymer length and stability. Together, these findings establish CozE proteins as novel players in membrane homeostasis and LTA biosynthesis in S. aureus.IMPORTANCELipoteichoic acids are major constituents of the cell wall of Gram-positive bacteria. These anionic polymers are important virulence factors and modulators of antibiotic susceptibility in the important pathogen Staphylococcus aureus. They are also critical for maintaining cell integrity and facilitating proper cell division. In this work, we discover that a family of membrane proteins named CozE is involved in the biosynthesis of lipoteichoic acids (LTAs) in S. aureus. CozE proteins have previously been shown to affect bacterial cell division, but we here show that these proteins affect LTA length and stability, as well as the flipping of glycolipids between membrane leaflets. This new mechanism of LTA control may thus have implications for the virulence and antibiotic susceptibility of S. aureus.
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Affiliation(s)
- Maria Disen Barbuti
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | | | - Ine Storaker Myrbråten
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Adrien Ducret
- Molecular Microbiology and Structural Biochemistry, CNRS UM 5086, Université de Lyon, Lyon, France
| | - Gro Anita Stamsås
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Linus Wilhelm
- Molecular Microbiology and Structural Biochemistry, CNRS UM 5086, Université de Lyon, Lyon, France
| | - Xue Liu
- Department of Pathogen, Biology, International Cancer Center, Shenzhen University Medical School, Shenzhen, Guangdong, China
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Zhian Salehian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Daniel Straume
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
| | - Christophe Grangeasse
- Molecular Microbiology and Structural Biochemistry, CNRS UM 5086, Université de Lyon, Lyon, France
| | - Camilo Perez
- Biozentrum, University of Basel, Basel, Switzerland
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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5
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Joyce LR, Kim S, Spencer BL, Christensen PM, Palmer KL, Guan Z, Siegenthaler JA, Doran KS. Streptococcus agalactiae glycolipids promote virulence by thwarting immune cell clearance. SCIENCE ADVANCES 2024; 10:eadn7848. [PMID: 38809989 PMCID: PMC11135403 DOI: 10.1126/sciadv.adn7848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 04/25/2024] [Indexed: 05/31/2024]
Abstract
Streptococcus agalactiae [group B Streptococcus (GBS)] is a leading cause of neonatal meningitis, with late-onset disease (LOD) occurring after gastrointestinal tract colonization in infants. Bacterial membrane lipids are essential for host-pathogen interactions, and the functions of glycolipids are yet to be fully elucidated. GBS synthesizes three major glycolipids: glucosyl-diacylglycerol (Glc-DAG), diglucosyl-DAG (Glc2-DAG), and lysyl-Glc-DAG (Lys-Glc-DAG). Here, we identify the enzyme, IagB, as responsible for biosynthesis of Glc-DAG, the precursor for the two other glycolipids in GBS. To examine the collective role of glycolipids to GBS virulence, we adapted a murine model of neonatal meningitis to simulate LOD. The GBS∆iagB mutant traversed the gut-epithelial barrier comparable to wild type but was severely attenuated in bloodstream survival, resulting in decreased bacterial loads in the brain. The GBS∆iagB mutant was more susceptible to neutrophil killing and membrane targeting by host antimicrobial peptides. This work reveals an unexplored function of GBS glycolipids with their ability to protect the bacterial cell from host antimicrobial killing.
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Affiliation(s)
- Luke R. Joyce
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Sol Kim
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Brady L. Spencer
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Priya M. Christensen
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Kelli L. Palmer
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, USA
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Julie A. Siegenthaler
- Department of Pediatrics, Section of Developmental Biology, University of Colorado School of Medicine, Aurora, CO, USA
| | - Kelly S. Doran
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA
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6
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Zhang P, Liu Z. Structural insights into the transporting and catalyzing mechanism of DltB in LTA D-alanylation. Nat Commun 2024; 15:3404. [PMID: 38649359 PMCID: PMC11035591 DOI: 10.1038/s41467-024-47783-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 04/12/2024] [Indexed: 04/25/2024] Open
Abstract
DltB, a model member of the Membrane-Bound O-AcylTransferase (MBOAT) superfamily, plays a crucial role in D-alanylation of the lipoteichoic acid (LTA), a significant component of the cell wall of gram-positive bacteria. This process stabilizes the cell wall structure, influences bacterial virulence, and modulates the host immune response. Despite its significance, the role of DltB is not well understood. Through biochemical analysis and cryo-EM imaging, we discover that Streptococcus thermophilus DltB forms a homo-tetramer on the cell membrane. We further visualize DltB in an apo form, in complex with DltC, and in complex with its inhibitor amsacrine (m-AMSA). Each tetramer features a central hole. The C-tunnel of each protomer faces the intratetramer interface and provides access to the periphery membrane. Each protomer binds a DltC without changing the tetrameric organization. A phosphatidylglycerol (PG) molecule in the substrate-binding site may serve as an LTA carrier. The inhibitor m-AMSA bound to the L-tunnel of each protomer blocks the active site. The tetrameric organization of DltB provides a scaffold for catalyzing D-alanyl transfer and regulating the channel opening and closing. Our findings unveil DltB's dual function in the D-alanylation pathway, and provide insight for targeting DltB as a anti-virulence antibiotic.
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Affiliation(s)
- Pingfeng Zhang
- Cancer Center, Renmin Hospital of Wuhan University, Wuhan, China.
| | - Zheng Liu
- Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Shenzhen, China.
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Beck C, Krusche J, Notaro A, Walter A, Kränkel L, Vollert A, Stemmler R, Wittmann J, Schaller M, Slavetinsky C, Mayer C, De Castro C, Peschel A. Wall teichoic acid substitution with glucose governs phage susceptibility of Staphylococcus epidermidis. mBio 2024; 15:e0199023. [PMID: 38470054 PMCID: PMC11005348 DOI: 10.1128/mbio.01990-23] [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: 07/26/2023] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
The species- and clone-specific susceptibility of Staphylococcus cells for bacteriophages is governed by the structures and glycosylation patterns of wall teichoic acid (WTA) glycopolymers. The glycosylation-dependent phage-WTA interactions in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) have remained unknown. We report a new S. epidermidis WTA glycosyltransferase TagE whose deletion confers resistance to siphoviruses such as ΦE72 but enables binding of otherwise unbound podoviruses. S. epidermidis glycerolphosphate WTA was found to be modified with glucose in a tagE-dependent manner. TagE is encoded together with the enzymes PgcA and GtaB providing uridine diphosphate-activated glucose. ΦE72 transduced several other CoNS species encoding TagE homologs, suggesting that WTA glycosylation via TagE is a frequent trait among CoNS that permits interspecies horizontal gene transfer. Our study unravels a crucial mechanism of phage-Staphylococcus interaction and horizontal gene transfer, and it will help in the design of anti-staphylococcal phage therapies.IMPORTANCEPhages are highly specific for certain bacterial hosts, and some can transduce DNA even across species boundaries. How phages recognize cognate host cells remains incompletely understood. Phages infecting members of the genus Staphylococcus bind to wall teichoic acid (WTA) glycopolymers with highly variable structures and glycosylation patterns. How WTA is glycosylated in the opportunistic pathogen Staphylococcus epidermidis and in other coagulase-negative staphylococci (CoNS) species has remained unknown. We describe that S. epidermidis glycosylates its WTA backbone with glucose, and we identify a cluster of three genes responsible for glucose activation and transfer to WTA. Their inactivation strongly alters phage susceptibility patterns, yielding resistance to siphoviruses but susceptibility to podoviruses. Many different CoNS species with related glycosylation genes can exchange DNA via siphovirus ΦE72, suggesting that glucose-modified WTA is crucial for interspecies horizontal gene transfer. Our finding will help to develop antibacterial phage therapies and unravel routes of genetic exchange.
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Affiliation(s)
- Christian Beck
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Janes Krusche
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Anna Notaro
- Department of Agricultural Sciences, University of Naples, Naples, Italy
| | - Axel Walter
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions/Glycobiology, University of Tübingen, Tübingen, Germany
| | - Lara Kränkel
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Anneli Vollert
- Electron-Microscopy, Department of Dermatology, University Hospital Tübingen, Tübingen, Germany
| | - Regine Stemmler
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Johannes Wittmann
- Leibniz Institute, DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Martin Schaller
- Electron-Microscopy, Department of Dermatology, University Hospital Tübingen, Tübingen, Germany
| | - Christoph Slavetinsky
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
- Pediatric Surgery and Urology, University Children's Hospital Tübingen, University of Tübingen, Tübingen, Germany
| | - Christoph Mayer
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Organismic Interactions/Glycobiology, University of Tübingen, Tübingen, Germany
| | | | - Andreas Peschel
- Cluster of Excellence “Controlling Microbes to Fight Infections (CMFI)”, University of Tübingen, Tübingen, Germany
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Infection Biology, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
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8
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Ibrahim AM, Azam MS, Schneewind O, Missiakas D. Processing of LtaS restricts LTA assembly and YSIRK preprotein trafficking into Staphylococcus aureus cross-walls. mBio 2024; 15:e0285223. [PMID: 38174934 PMCID: PMC10865820 DOI: 10.1128/mbio.02852-23] [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: 10/25/2023] [Accepted: 10/31/2023] [Indexed: 01/05/2024] Open
Abstract
Septal membranes of Staphylococcus aureus serve as the site of secretion for precursors endowed with the YSIRK motif. Depletion of ltaS, a gene required for lipoteichoic acid (LTA) synthesis, results in the loss of restricted trafficking of YSIRK precursors to septal membranes. Here, we seek to understand the mechanism that ties LTA assembly and trafficking of YSIRK precursors. We confirm that catalytically inactive lipoteichoic acid synthase (LtaS)T300A does not support YSIRK precursor trafficking to septa. We hypothesize that the enzyme's reactants [gentiobiosyldiacylglycerol (Glc2-DAG) and phosphatidylglycerol (PG)] or products [LTA and diacylglycerol (DAG)], not LtaS, must drive this process. Indeed, we observe that septal secretion of the staphylococcal protein A YSIRK precursor is lost in ypfP and ltaA mutants that produce glycerophosphate polymers [poly(Gro-P)] without the Glc2-DAG lipid anchor. These mutants display longer poly(Gro-P) chains, implying enhanced PG consumption and DAG production. Our experiments also reveal that in the absence of Glc2-DAG, the processing of LtaS to the extracellular catalytic domain, eLtaS, is impaired. Conversely, LTA polymerization is delayed in a strain producing LtaSS218P, a variant processed more slowly than LtaS. We conclude that Glc2-DAG binding to the enzyme couples catalysis by LtaS and the physical release of eLtaS. We propose a model for the temporal and localized assembly of LTA into cross-walls. When LtaS is not processed in a timely manner, eLtaS no longer diffuses upon daughter cell splitting, LTA assembly continues, and the unique septal-lipid pool, PG over DAG ratio, is not established. This results in profound physiological changes in S. aureus cells, including the inability to restrict the secretion of YSIRK precursors at septal membranes.IMPORTANCEIn Staphylococcus aureus, peptidoglycan is assembled at the septum. Dedicated cell division proteins coordinate septal formation and the fission of daughter cells. Lipoteichoic acid (LTA) assembly and trafficking of preproteins with a YSIRK motif also occur at the septum. This begs the question as to whether cell division components also recruit these two pathways. This study shows that the processing of lipoteichoic acid synthase (LtaS) to extracellular LtaS by signal peptidase is regulated by gentiobiosyldiacylglycerol (Glc2-DAG), the priming substrate for LTA assembly. A model is proposed whereby a key substrate controls the temporal and spatial activity of an enzyme. In turn, this mechanism enables the establishment of a unique and transient lipid pool that defines septal membranes as a targeting site for the secretion of YSIRK preproteins.
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Affiliation(s)
- Amany M. Ibrahim
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
- Department of Microbiology and Immunology, Faculty of Pharmacy, Sinai University, Arish, Egypt
| | - Muhammad S. Azam
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
| | - Olaf Schneewind
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
| | - Dominique Missiakas
- Department of Microbiology, Howard Taylor Ricketts Laboratory, The University of Chicago, Lemont, Illinois, USA
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9
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Millership C, Gründling A. Type I Lipoteichoic Acid (LTA) Detection by Western Blot. Methods Mol Biol 2024; 2727:95-106. [PMID: 37815711 DOI: 10.1007/978-1-0716-3491-2_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] [Indexed: 10/11/2023]
Abstract
Type I lipoteichoic acid (LTA) is a glycerol phosphate polymer found in the cell envelope of diverse Gram-positive bacteria including Staphylococcus aureus, Bacillus subtilis, and Listeria monocytogenes. The polymer is linked by a lipid anchor to the outer leaflet of the bacterial membrane and in some bacteria can also be shed and detected in the culture supernatant. Here, we describe a simple and rapid western blot method for the detection of Type I LTA in bacterial cell extracts and culture supernatant fractions using a polyglycerol phosphate specific monoclonal LTA antibody.
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Affiliation(s)
- Charlotte Millership
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, UK
| | - Angelika Gründling
- Section of Molecular Microbiology and Centre for Bacterial Resistance Biology (CBRB), Imperial College London, London, UK.
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10
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Han J, Zhao X, Zhao X, Li P, Gu Q. Insight into the structure, biosynthesis, isolation method and biological function of teichoic acid in different gram-positive microorganisms: A review. Int J Biol Macromol 2023; 253:126825. [PMID: 37696369 DOI: 10.1016/j.ijbiomac.2023.126825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 09/13/2023]
Abstract
Teichoic acid (TA) is a weakly anionic polymer present in the cell walls of Gram-positive bacteria. It can be classified into wall teichoic acid (WTA) and lipoteichoic acid (LTA) based on its localization in the cell wall. The structure and biosynthetic pathway of TAs are strain-specific and have a significant role in maintaining cell wall stability. TAs have various beneficial functions, such as immunomodulatory, anticancer and antioxidant activities. However, the purity and yield of TAs are generally not high, and different isolation methods may even affect their structural integrity, which limits the research progress on the probiotic functions of TA. This paper reviews an overview of the structure and biosynthetic pathway of TAs in different strains, as well as the research progress of the isolation and purification methods of TAs. Furthermore, this review also highlights the current research status on the biological functions of TAs. Through a comprehensive understanding of this review, it is expected to pave the way for advancements in isolating and purifying high-quality TAs and, in turn, lay a foundation for contributing to the development of targeted probiotic therapies.
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Affiliation(s)
- Jiarun Han
- Key Laboratory for Food Microbial Technology of Zhejiang Province, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Xin Zhao
- Key Laboratory for Food Microbial Technology of Zhejiang Province, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Xilian Zhao
- Key Laboratory for Food Microbial Technology of Zhejiang Province, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Ping Li
- Key Laboratory for Food Microbial Technology of Zhejiang Province, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China
| | - Qing Gu
- Key Laboratory for Food Microbial Technology of Zhejiang Province, College of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, Zhejiang 310018, People's Republic of China.
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11
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Gouveia A, Pinto D, Vítor JMB, São-José C. Cellular and Enzymatic Determinants Impacting the Exolytic Action of an Anti-Staphylococcal Enzybiotic. Int J Mol Sci 2023; 25:523. [PMID: 38203699 PMCID: PMC10778630 DOI: 10.3390/ijms25010523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Bacteriophage endolysins are bacteriolytic enzymes that have been explored as potential weapons to fight antibiotic-resistant bacteria. Despite several studies support the application of endolysins as enzybiotics, detailed knowledge on cellular and enzymatic factors affecting their lytic activity is still missing. The bacterial membrane proton motive force (PMF) and certain cell wall glycopolymers of Gram-positive bacteria have been implicated in some tolerance to endolysins. Here, we studied how the anti-staphylococcal endolysin Lys11, a modular enzyme with two catalytic domains (peptidase and amidase) and a cell binding domain (CBD11), responded to changes in the chemical and/or electric gradients of the PMF (ΔpH and Δψ, respectively). We show that simultaneous dissipation of both gradients enhances endolysin binding to cells and lytic activity. The collapse of ΔpH is preponderant in the stimulation of Lys11 lytic action, while the dissipation of Δψ is mainly associated with higher endolysin binding. Interestingly, this binding depends on the amidase domain. The peptidase domain is responsible for most of the Lys11 bacteriolytic activity. Wall teichoic acids (WTAs) are confirmed as major determinants of endolysin tolerance, in part by severely hindering CBD11 binding activity. In conclusion, the PMF and WTA interfere differently with the endolysin functional domains, affecting both the binding and catalytic efficiencies.
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Affiliation(s)
- Ana Gouveia
- Phage Biology Research and Infection Control (PhaBRIC), Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (A.G.); (D.P.)
| | - Daniela Pinto
- Phage Biology Research and Infection Control (PhaBRIC), Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (A.G.); (D.P.)
| | - Jorge M. B. Vítor
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal;
| | - Carlos São-José
- Phage Biology Research and Infection Control (PhaBRIC), Research Institute for Medicines (iMed.ULisboa), Faculdade de Farmácia, Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal; (A.G.); (D.P.)
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12
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Deng X, Xu H, Li D, Chen J, Yu Z, Deng Q, Li P, Zheng J, Zhang H. Mechanisms of Rapid Bactericidal and Anti-Biofilm Alpha-Mangostin In Vitro Activity against Staphylococcus aureus. Pol J Microbiol 2023; 72:199-208. [PMID: 37314356 DOI: 10.33073/pjm-2023-021] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 04/16/2023] [Indexed: 06/15/2023] Open
Abstract
Alpha-mangostin (α-mangostin) was discovered as a potent natural product against Gram-positive bacteria, whereas the underlying molecular mechanisms are still unclear. This study indicated that α-mangostin (at 4 × MIC) rapidly killed Staphylococcus aureus planktonic cells more effectively (at least 2-log10 CFU/ml) than daptomycin, vancomycin and linezolid at 1 and 3 h in the time-killing test. Interestingly, this study also found that a high concentration of α-mangostin (≥4×MIC) significantly reduced established biofilms of S. aureus. There were 58 single nucleotide polymorphisms (SNPs) in α-mangostin nonsensitive S. aureus isolates by whole-genome sequencing, of which 35 SNPs were located on both sides of the sarT gene and 10 SNPs in the sarT gene. A total of 147 proteins with a different abundance were determined by proteomics analysis, of which 91 proteins increased, whereas 56 proteins decreased. The abundance of regulatory proteins SarX and SarZ increased. In contrast, the abundance of SarT and IcaB was significantly reduced (they belonged to SarA family and ica system, associated with the biofilm formation of S. aureus). The abundance of cell membrane proteins VraF and DltC was augmented, but the abundance of cell membrane protein UgtP remarkably decreased. Propidium iodide and DiBaC4(3) staining assay revealed that the fluorescence intensities of DNA and the cell membrane were elevated in the α-mangostin treated S. aureus isolates. In conclusion, this study reveals that α-mangostin was effective against S. aureus planktonic cells by targeting cell membranes. The anti-biofilm effect of α-mangostin may be through inhibiting the function of SarT and IcaB.
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Affiliation(s)
- Xiangbin Deng
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Hongbo Xu
- 2Department of Critical Care Medicine and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Duoyun Li
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Jinlian Chen
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Zhijian Yu
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Qiwen Deng
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Peiyu Li
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Jinxin Zheng
- 1Department of Infectious Diseases and Shenzhen Key Laboratory for Endogenous Infections, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
| | - Haigang Zhang
- 2Department of Critical Care Medicine and the Key Lab of Endogenous Infection, Shenzhen Nanshan People's Hospital, and the 6th Affiliated Hospital of Shenzhen University Medical School, Shenzhen, China
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13
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Ledger EVK, Lau K, Tate EW, Edwards AM. XerC Is Required for the Repair of Antibiotic- and Immune-Mediated DNA Damage in Staphylococcus aureus. Antimicrob Agents Chemother 2023; 67:e0120622. [PMID: 36802166 PMCID: PMC10019262 DOI: 10.1128/aac.01206-22] [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: 02/23/2023] Open
Abstract
To survive in the host environment, pathogenic bacteria need to be able to repair DNA damage caused by both antibiotics and the immune system. The SOS response is a key bacterial pathway to repair DNA double-strand breaks and may therefore be a good target for novel therapeutics to sensitize bacteria to antibiotics and the immune response. However, the genes required for the SOS response in Staphylococcus aureus have not been fully established. Therefore, we carried out a screen of mutants involved in various DNA repair pathways to understand which were required for induction of the SOS response. This led to the identification of 16 genes that may play a role in SOS response induction and, of these, 3 that affected the susceptibility of S. aureus to ciprofloxacin. Further characterization revealed that, in addition to ciprofloxacin, loss of the tyrosine recombinase XerC increased the susceptibility of S. aureus to various classes of antibiotics, as well as to host immune defenses. Therefore, the inhibition of XerC may be a viable therapeutic approach to sensitize S. aureus to both antibiotics and the immune response.
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Affiliation(s)
- Elizabeth V. K. Ledger
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Katie Lau
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Edward W. Tate
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, United Kingdom
| | - Andrew M. Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
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14
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Abstract
Gram-positive bacterial cells are protected from the environment by a cell envelope that is comprised of a thick layer of peptidoglycan that maintains cell shape and teichoic acid polymers whose biological function remains unclear. In Bacillus subtilis, the loss of all class A penicillin-binding proteins (aPBPs), which function in peptidoglycan synthesis, is conditionally lethal. Here, we show that this lethality is associated with an alteration of lipoteichoic acids (LTAs) and the accumulation of the major autolysin LytE in the cell wall. Our analysis provides further evidence that the length and abundance of LTAs act to regulate the cellular level and activity of autolytic enzymes, specifically LytE. Importantly, we identify a novel function for the aminoacyl-phosphatidylglycerol synthase MprF in the modulation of LTA biosynthesis in both B. subtilis and Staphylococcus aureus. This finding has implications for our understanding of antimicrobial resistance (particularly to daptomycin) in clinically relevant bacteria and the involvement of MprF in the virulence of pathogens such as methicillin-resistant S. aureus (MRSA). IMPORTANCE In Gram-positive bacteria such as Bacillus subtilis and Staphylococcus aureus, the cell envelope is a structure that protects the cells from the environment but is also dynamic in that it must be modified in a controlled way to allow cell growth. In this study, we show that lipoteichoic acids (LTAs), which are anionic polymers attached to the membrane, have a direct role in modulating the cellular abundance of cell wall-degrading enzymes. We also find that the apparent length of the LTA is modulated by the activity of the enzyme MprF, previously implicated in modifications of the cell membrane leading to resistance to antimicrobial peptides. These findings are important contributions to our understanding of how bacteria balance cell wall synthesis and degradation to permit controlled growth and division. These results also have implications for the interpretation of antibiotic resistance, particularly for the clinical treatment of MRSA infections.
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15
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Abstract
Almost all bactericidal drugs require bacterial replication and/or metabolic activity for their killing activity. When these processes are inhibited by bacteriostatic antibiotics, bacterial killing is significantly reduced. One notable exception is the lipopeptide antibiotic daptomycin, which has been reported to efficiently kill growth-arrested bacteria. However, these studies employed only short periods of growth arrest (<1 h), which may not fully represent the duration of growth arrest that can occur in vivo. We found that a growth inhibitory concentration of the protein synthesis inhibitor tetracycline led to a time-dependent induction of daptomycin tolerance in S. aureus, with an approximately 100,000-fold increase in survival after 16 h of growth arrest, relative to exponential-phase bacteria. Daptomycin tolerance required glucose and was associated with increased production of the cell wall polymers peptidoglycan and wall-teichoic acids. However, while the accumulation of peptidoglycan was required for daptomycin tolerance, only a low abundance of wall teichoic acid was necessary. Therefore, whereas tolerance to most antibiotics occurs passively due to a lack of metabolic activity and/or replication, daptomycin tolerance arises via active cell wall remodelling. IMPORTANCE Understanding why antibiotics sometimes fail to cure infections is fundamental to improving treatment outcomes. This is a major challenge when it comes to Staphylococcus aureus because this pathogen causes several different chronic or recurrent infections. Previous work has shown that a lack of replication, as often occurs during infection, makes bacteria tolerant of most bactericidal antibiotics. However, one antibiotic that has been reported to kill nonreplicating bacteria is daptomycin. In this work, we show that the growth arrest of S. aureus does in fact lead to daptomycin tolerance, but it requires time, nutrients, and biosynthetic pathways, making it distinct from other types of antibiotic tolerance that occur in nonreplicating bacteria.
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16
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Li X, Cai Y, Xia Q, Liao Y, Qin R. Antibacterial sensitizers from natural plants: A powerful weapon against methicillin-resistant Staphylococcus aureus. Front Pharmacol 2023; 14:1118793. [PMID: 36909155 PMCID: PMC9998539 DOI: 10.3389/fphar.2023.1118793] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/13/2023] [Indexed: 02/26/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) is a drug-resistant bacterium that can cause a range of infections with high morbidity and mortality, including pneumonia, etc. Therefore, development of new drugs or therapeutic strategies against MRSA is urgently needed. Increasing evidence has shown that combining antibiotics with "antibacterial sensitizers" which itself has no effect on MRSA, is highly effective against MRSA. Many studies showed the development of antibacterial sensitizers from natural plants may be a promising strategy against MRSA because of their low side effects, low toxicity and multi-acting target. In our paper, we first reviewed the resistance mechanisms of MRSA including "Resistance to Beta-Lactams", "Resistance to Glycopeptide antibiotics", "Resistance to Macrolides, Aminoglycosides, and Oxazolidinones" etc. Moreover, we summarized the possible targets for antibacterial sensitizers against MRSA. Furthermore, we reviewed the synergy effects of active monomeric compounds from natural plants combined with antibiotics against MRSA and their corresponding mechanisms over the last two decades. This review provides a novel approach to overcome antibiotic resistance in MRSA.
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Affiliation(s)
- Xiaoli Li
- Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China.,Chongqing Key Laboratory of Drug Metabolism, Chongqing, China
| | - Yongqing Cai
- Department of Pharmacy, Daping Hospital, Army Medical University, Chongqing, China
| | - Qinchuan Xia
- Fuan Pharmaceutical Group Chongqing Bosen Pharmaceutical Co., Ltd., Chongqing, China
| | - Yongqun Liao
- Fuan Pharmaceutical Group Chongqing Bosen Pharmaceutical Co., Ltd., Chongqing, China
| | - Rongxin Qin
- Department of Pharmacology, College of Pharmacy, Army Medical University (The Third Military Medical University), Chongqing, China
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17
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Giacometti SI, MacRae MR, Dancel-Manning K, Bhabha G, Ekiert DC. Lipid Transport Across Bacterial Membranes. Annu Rev Cell Dev Biol 2022; 38:125-153. [PMID: 35850151 DOI: 10.1146/annurev-cellbio-120420-022914] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The movement of lipids within and between membranes in bacteria is essential for building and maintaining the bacterial cell envelope. Moving lipids to their final destination is often energetically unfavorable and does not readily occur spontaneously. Bacteria have evolved several protein-mediated transport systems that bind specific lipid substrates and catalyze the transport of lipids across membranes and from one membrane to another. Specific protein flippases act in translocating lipids across the plasma membrane, overcoming the obstacle of moving relatively large and chemically diverse lipids between leaflets of the bilayer. Active transporters found in double-membraned bacteria have evolved sophisticated mechanisms to traffic lipids between the two membranes, including assembling to form large, multiprotein complexes that resemble bridges, shuttles, and tunnels, shielding lipids from the hydrophilic environment of the periplasm during transport. In this review, we explore our current understanding of the mechanisms thought to drive bacterial lipid transport.
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Affiliation(s)
- Sabrina I Giacometti
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
| | - Mark R MacRae
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
| | - Kristen Dancel-Manning
- Office of Science and Research, New York University School of Medicine, New York, NY, USA;
| | - Gira Bhabha
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
| | - Damian C Ekiert
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
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18
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Antimicrobial Activity of Rhenium Di- and Tricarbonyl Diimine Complexes: Insights on Membrane-Bound S. aureus Protein Binding. Pharmaceuticals (Basel) 2022; 15:ph15091107. [PMID: 36145328 PMCID: PMC9501577 DOI: 10.3390/ph15091107] [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: 08/04/2022] [Revised: 08/31/2022] [Accepted: 08/31/2022] [Indexed: 11/16/2022] Open
Abstract
Antimicrobial resistance is one of the major human health threats, with significant impacts on the global economy. Antibiotics are becoming increasingly ineffective as drug-resistance spreads, imposing an urgent need for new and innovative antimicrobial agents. Metal complexes are an untapped source of antimicrobial potential. Rhenium complexes, amongst others, are particularly attractive due to their low in vivo toxicity and high antimicrobial activity, but little is known about their targets and mechanism of action. In this study, a series of rhenium di- and tricarbonyl diimine complexes were prepared and evaluated for their antimicrobial potential against eight different microorganisms comprising Gram-negative and -positive bacteria. Our data showed that none of the Re dicarbonyl or neutral tricarbonyl species have either bactericidal or bacteriostatic potential. In order to identify possible targets of the molecules, and thus possibly understand the observed differences in the antimicrobial efficacy of the molecules, we computationally evaluated the binding affinity of active and inactive complexes against structurally characterized membrane-bound S. aureus proteins. The computational analysis indicates two possible major targets for this class of compounds, namely lipoteichoic acids flippase (LtaA) and lipoprotein signal peptidase II (LspA). Our results, consistent with the published in vitro studies, will be useful for the future design of rhenium tricarbonyl diimine-based antibiotics.
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19
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Wall Teichoic Acids Facilitate the Release of Toxins from the Surface of Staphylococcus aureus. Microbiol Spectr 2022; 10:e0101122. [PMID: 35863033 PMCID: PMC9430763 DOI: 10.1128/spectrum.01011-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major feature of the pathogenicity of Staphylococcus aureus is its ability to secrete cytolytic toxins. This process involves the translocation of the toxins from the cytoplasm through the bacterial membrane and the cell wall to the external environment. The process of their movement through the membrane is relatively well defined, involving both general and toxin-specific secretory systems. Movement of the toxins through the cell wall was considered to involve the passive diffusion of the proteins through the porous cell wall structures; however, recent work suggests that this is more complex, and here we demonstrate a role for the wall teichoic acids (WTA) in this process. Utilizing a genome-wide association approach, we identified a polymorphism in the locus encoding the WTA biosynthetic machinery as associated with the cytolytic activity of the bacteria. We verified this association using an isogenic mutant set and found that WTA are required for the release of several cytolytic toxins from the bacterial cells. We show that this effect is mediated by a change in the electrostatic charge across the cell envelope that results from the loss of WTA. As a major target for the development of novel therapeutics, it is important that we fully understand the entire process of cytolytic toxin production and release. These findings open up a new aspect to the process of toxin release by a major human pathogen while also demonstrating that clinical isolates can utilize WTA production to vary their cytotoxicity, thereby altering their pathogenic capabilities. IMPORTANCE The production and release of cytolytic toxins is a critical aspect for the pathogenicity of many bacterial pathogens. In this study, we demonstrate a role for wall teichoic acids, molecules that are anchored to the peptidoglycan of the bacterial cell wall, in the release of toxins from S. aureus cells into the extracellular environment. Our findings suggest that this effect is mediated by a gradient of electrostatic charge which the presence of the negatively charged WTA molecules create across the cell envelope. This work brings an entirely new aspect to our understanding of the cytotoxicity of S. aureus and demonstrates a further means by which this major human pathogen can adapt its pathogenic capabilities.
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20
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Chee Wezen X, Chandran A, Eapen RS, Waters E, Bricio-Moreno L, Tosi T, Dolan S, Millership C, Kadioglu A, Gründling A, Itzhaki LS, Welch M, Rahman T. Structure-Based Discovery of Lipoteichoic Acid Synthase Inhibitors. J Chem Inf Model 2022; 62:2586-2599. [PMID: 35533315 PMCID: PMC9131456 DOI: 10.1021/acs.jcim.2c00300] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Indexed: 01/20/2023]
Abstract
Lipoteichoic acid synthase (LtaS) is a key enzyme for the cell wall biosynthesis of Gram-positive bacteria. Gram-positive bacteria that lack lipoteichoic acid (LTA) exhibit impaired cell division and growth defects. Thus, LtaS appears to be an attractive antimicrobial target. The pharmacology around LtaS remains largely unexplored with only two small-molecule LtaS inhibitors reported, namely "compound 1771" and the Congo red dye. Structure-based drug discovery efforts against LtaS remain unattempted due to the lack of an inhibitor-bound structure of LtaS. To address this, we combined the use of a molecular docking technique with molecular dynamics (MD) simulations to model a plausible binding mode of compound 1771 to the extracellular catalytic domain of LtaS (eLtaS). The model was validated using alanine mutagenesis studies combined with isothermal titration calorimetry. Additionally, lead optimization driven by our computational model resulted in an improved version of compound 1771, namely, compound 4 which showed greater affinity for binding to eLtaS than compound 1771 in biophysical assays. Compound 4 reduced LTA production in S. aureus dose-dependently, induced aberrant morphology as seen for LTA-deficient bacteria, and significantly reduced bacteria titers in the lung of mice infected with S. aureus. Analysis of our MD simulation trajectories revealed the possible formation of a transient cryptic pocket in eLtaS. Virtual screening (VS) against the cryptic pocket led to the identification of a new class of inhibitors that could potentiate β-lactams against methicillin-resistant S. aureus. Our overall workflow and data should encourage further drug design campaign against LtaS. Finally, our work reinforces the importance of considering protein conformational flexibility to a successful VS endeavor.
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Affiliation(s)
- Xavier Chee Wezen
- Science
Program, School of Chemical Engineering and Science, Faculty of Engineering,
Computing and Science, Swinburne University
of Technology Sarawak, Kuching 93350, Malaysia
| | - Aneesh Chandran
- Department
of Biotechnology & Microbiology, Kannur
University, Kannur 670 661, Kerala, India
| | | | - Elaine Waters
- Department
of Clinical Infection Microbiology and Immunology, Institute of Infection
and Global Health, University of Liverpool, Liverpool L69 7BE, U.K.
| | - Laura Bricio-Moreno
- Department
of Clinical Infection Microbiology and Immunology, Institute of Infection
and Global Health, University of Liverpool, Liverpool L69 7BE, U.K.
| | - Tommaso Tosi
- Section
of Molecular Microbiology and MRC Centre for Molecular Bacteriology
and Infection, Imperial College London, London SW7 2AZ, U.K.
| | - Stephen Dolan
- Department
of Biochemistry, University of Cambridge, Cambridge CB2 1QW, U.K.
| | - Charlotte Millership
- Section
of Molecular Microbiology and MRC Centre for Molecular Bacteriology
and Infection, Imperial College London, London SW7 2AZ, U.K.
| | - Aras Kadioglu
- Department
of Clinical Infection Microbiology and Immunology, Institute of Infection
and Global Health, University of Liverpool, Liverpool L69 7BE, U.K.
| | - Angelika Gründling
- Section
of Molecular Microbiology and MRC Centre for Molecular Bacteriology
and Infection, Imperial College London, London SW7 2AZ, U.K.
| | - Laura S. Itzhaki
- Department
of PharmacologyUniversity of CambridgeCambridgeCB2 1PDU.K.
| | - Martin Welch
- Department
of Biochemistry, University of Cambridge, Cambridge CB2 1QW, U.K.
| | - Taufiq Rahman
- Department
of PharmacologyUniversity of CambridgeCambridgeCB2 1PDU.K.
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21
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Naclerio GA, Abutaleb NS, Onyedibe KI, Karanja C, Eldesouky HE, Liang HW, Dieterly A, Aryal UK, Lyle T, Seleem MN, Sintim HO. Mechanistic Studies and In Vivo Efficacy of an Oxadiazole-Containing Antibiotic. J Med Chem 2022; 65:6612-6630. [PMID: 35482444 PMCID: PMC9124606 DOI: 10.1021/acs.jmedchem.1c02034] [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: 11/28/2022]
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) infections are still difficult to treat, despite the availability of many FDA-approved antibiotics. Thus, new compound scaffolds are still needed to treat MRSA. The oxadiazole-containing compound, HSGN-94, has been shown to reduce lipoteichoic acid (LTA) in S. aureus, but the mechanism that accounts for LTA biosynthesis inhibition remains uncharacterized. Herein, we report the elucidation of the mechanism by which HSGN-94 inhibits LTA biosynthesis via utilization of global proteomics, activity-based protein profiling, and lipid analysis via multiple reaction monitoring (MRM). Our data suggest that HSGN-94 inhibits LTA biosynthesis via direct binding to PgcA and downregulation of PgsA. We further show that HSGN-94 reduces the MRSA load in skin infection (mouse) and decreases pro-inflammatory cytokines in MRSA-infected wounds. Collectively, HSGN-94 merits further consideration as a potential drug for staphylococcal infections.
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Affiliation(s)
- George A Naclerio
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, Indiana 47907, United States
| | - Nader S Abutaleb
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
| | - Kenneth I Onyedibe
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
| | - Caroline Karanja
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hassan E Eldesouky
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
| | - Hsin-Wen Liang
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
| | - Alexandra Dieterly
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
| | - Uma K Aryal
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Proteomics Facility, Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, United States
| | - Tiffany Lyle
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
- Center for Comparative Translational Research, Purdue University, West Lafayette, Indiana 47907, United States
| | - Mohamed N Seleem
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, United States
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907, United States
- Center for Emerging, Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061, United States
| | - Herman O Sintim
- Chemistry Department, Institute for Drug Discovery, Purdue University, West Lafayette, Indiana 47907, United States
- Purdue Institute of Inflammation, Immunology, and Infectious Disease, Purdue University, West Lafayette, Indiana 47907, United States
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22
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Muscato J, Morris HG, Mychack A, Rajagopal M, Baidin V, Hesser AR, Lee W, İnecik K, Wilson LJ, Kraml CM, Meredith TC, Walker S. Rapid Inhibitor Discovery by Exploiting Synthetic Lethality. J Am Chem Soc 2022; 144:3696-3705. [PMID: 35170959 PMCID: PMC9012225 DOI: 10.1021/jacs.1c12697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Synthetic lethality occurs when inactivation of two genes is lethal but inactivation of either single gene is not. This phenomenon provides an opportunity for efficient compound discovery. Using differential growth screens, one can identify biologically active compounds that selectively inhibit proteins within the synthetic lethal network of any inactivated gene. Here, based purely on synthetic lethalities, we identified two compounds as the only possible inhibitors of Staphylococcus aureus lipoteichoic acid (LTA) biosynthesis from a screen of ∼230,000 compounds. Both compounds proved to inhibit the glycosyltransferase UgtP, which assembles the LTA glycolipid anchor. UgtP is required for β-lactam resistance in methicillin-resistant S. aureus (MRSA), and the inhibitors restored sensitivity to oxacillin in a highly resistant S. aureus strain. As no other compounds were pursued as possible LTA glycolipid assembly inhibitors, this work demonstrates the extraordinary efficiency of screens that exploit synthetic lethality to discover compounds that target specified pathways. The general approach should be applicable not only to other bacteria but also to eukaryotic cells.
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Affiliation(s)
- Jacob
D. Muscato
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Heidi G. Morris
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Aaron Mychack
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Mithila Rajagopal
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States,Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Vadim Baidin
- Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Anthony R. Hesser
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Wonsik Lee
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Kemal İnecik
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Laura J. Wilson
- Lotus
Separations LLC, B20 Frick Chemistry Laboratory, Princeton, New Jersey 08544, United States
| | - Christina M. Kraml
- Lotus
Separations LLC, B20 Frick Chemistry Laboratory, Princeton, New Jersey 08544, United States
| | - Timothy C. Meredith
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Suzanne Walker
- Department
of Microbiology, Harvard University, 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States,Department
of Chemistry and Chemical Biology, Harvard
University, 12 Oxford Street, Cambridge, Massachusetts 02138, United States,
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23
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Abstract
Biosynthesis of many important polysaccharides (including peptidoglycan, lipopolysaccharide, and N-linked glycans) necessitates the transport of lipid-linked oligosaccharides (LLO) across membranes from their cytosolic site of synthesis to their sites of utilization. Much of our current understanding of LLO transport comes from genetic, biochemical, and structural studies of the multidrug/oligosaccharidyl-lipid/polysaccharide (MOP) superfamily protein MurJ, which flips the peptidoglycan precursor lipid II. MurJ plays a pivotal role in bacterial cell wall synthesis and is an emerging antibiotic target. Here, we review the mechanism of LLO flipping by MurJ, including the structural basis for lipid II flipping and ion coupling. We then discuss inhibition of MurJ by antibacterials, including humimycins and the phage M lysis protein, as well as how studies on MurJ could provide insight into other flippases, both within and beyond the MOP superfamily. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Alvin C Y Kuk
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA; .,Current affiliation: Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore
| | - Aili Hao
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA;
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA;
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24
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Lambert E, Mehdipour AR, Schmidt A, Hummer G, Perez C. Evidence for a trap-and-flip mechanism in a proton-dependent lipid transporter. Nat Commun 2022; 13:1022. [PMID: 35197476 PMCID: PMC8866510 DOI: 10.1038/s41467-022-28361-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 01/23/2022] [Indexed: 02/08/2023] Open
Abstract
Transport of lipids across membranes is fundamental for diverse biological pathways in cells. Multiple ion-coupled transporters take part in lipid translocation, but their mechanisms remain largely unknown. Major facilitator superfamily (MFS) lipid transporters play central roles in cell wall synthesis, brain development and function, lipids recycling, and cell signaling. Recent structures of MFS lipid transporters revealed overlapping architectural features pointing towards a common mechanism. Here we used cysteine disulfide trapping, molecular dynamics simulations, mutagenesis analysis, and transport assays in vitro and in vivo, to investigate the mechanism of LtaA, a proton-dependent MFS lipid transporter essential for lipoteichoic acid synthesis in the pathogen Staphylococcus aureus. We reveal that LtaA displays asymmetric lateral openings with distinct functional relevance and that cycling through outward- and inward-facing conformations is essential for transport activity. We demonstrate that while the entire amphipathic central cavity of LtaA contributes to lipid binding, its hydrophilic pocket dictates substrate specificity. We propose that LtaA catalyzes lipid translocation by a ‘trap-and-flip’ mechanism that might be shared among MFS lipid transporters. LtaA catalyzes glycolipid translocation by a ‘trap-and-flip’ mechanism, pointing to a shared mechanistic model among MFS lipid transporters. Asymmetric lateral openings allow access of the entire lipid substrate to the amphipathic central cavity.
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Affiliation(s)
| | | | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Gerhard Hummer
- Institute of Biophysics, Goethe University Frankfurt, Frankfurt am Main, Germany.,Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Camilo Perez
- Biozentrum, University of Basel, Basel, Switzerland.
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25
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The cell envelope of Staphylococcus aureus selectively controls the sorting of virulence factors. Nat Commun 2021; 12:6193. [PMID: 34702812 PMCID: PMC8548510 DOI: 10.1038/s41467-021-26517-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 10/05/2021] [Indexed: 11/08/2022] Open
Abstract
Staphylococcus aureus bi-component pore-forming leukocidins are secreted toxins that directly target and lyse immune cells. Intriguingly, one of the leukocidins, Leukocidin AB (LukAB), is found associated with the bacterial cell envelope in addition to secreted into the extracellular milieu. Here, we report that retention of LukAB on the bacterial cells provides S. aureus with a pre-synthesized active toxin that kills immune cells. On the bacteria, LukAB is distributed as discrete foci in two distinct compartments: membrane-proximal and surface-exposed. Through genetic screens, we show that a membrane lipid, lysyl-phosphatidylglycerol (LPG), and lipoteichoic acid (LTA) contribute to LukAB deposition and release. Furthermore, by studying non-covalently surface-bound proteins we discovered that the sorting of additional exoproteins, such as IsaB, Hel, ScaH, and Geh, are also controlled by LPG and LTA. Collectively, our study reveals a multistep secretion system that controls exoprotein storage and protein translocation across the S. aureus cell wall.
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26
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Ftsh Sensitizes Methicillin-Resistant Staphylococcus aureus to β-Lactam Antibiotics by Degrading YpfP, a Lipoteichoic Acid Synthesis Enzyme. Antibiotics (Basel) 2021; 10:antibiotics10101198. [PMID: 34680778 PMCID: PMC8532640 DOI: 10.3390/antibiotics10101198] [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: 08/21/2021] [Revised: 09/17/2021] [Accepted: 09/27/2021] [Indexed: 12/20/2022] Open
Abstract
In the Gram-positive pathogen Staphylococcus aureus, FtsH, a membrane-bound metalloprotease, plays a critical role in bacterial virulence and stress resistance. This protease is also known to sensitize methicillin-resistant Staphylococcus aureus (MRSA) to β-lactam antibiotics; however, the molecular mechanism is not known. Here, by the analysis of FtsH substrate mutants, we found that FtsH sensitizes MRSA specifically to β-lactams by degrading YpfP, the enzyme synthesizing the anchor molecule for lipoteichoic acid (LTA). Both the overexpression of FtsH and the disruption of ypfP-sensitized MRSA to β-lactams were observed. The knockout mutation in ftsH and ypfP increased the thickness of the cell wall. The β-lactam sensitization coincided with the production of aberrantly large LTA molecules. The combination of three mutations in the rpoC, vraB, and SAUSA300_2133 genes blocked the β-lactam-sensitizing effect of FtsH. Murine infection with the ypfP mutant could be treated by oxacillin, a β-lactam antibiotic ineffective against MRSA; however, the effective concentration of oxacillin differed depending on the S. aureus strain. Our study demonstrated that the β-lactam sensitizing effect of FtsH is due to its digestion of YpfP. It also suggests that the larger LTA molecules are responsible for the β-lactam sensitization phenotype, and YpfP is a viable target for developing novel anti-MRSA drugs.
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27
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Cellular Mn/Zn Ratio Influences Phosphoglucomutase Activity and Capsule Production in Streptococcus pneumoniae D39. J Bacteriol 2021; 203:e0060220. [PMID: 33875543 PMCID: PMC8316032 DOI: 10.1128/jb.00602-20] [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] [Indexed: 01/16/2023] Open
Abstract
Capsular polysaccharide (CPS) is a major virulence determinant for many human-pathogenic bacteria. Although the essential functional roles for CPS in bacterial virulence have been established, knowledge of how CPS production is regulated remains limited. Streptococcus pneumoniae (pneumococcus) CPS expression levels and overall thickness change in response to available oxygen and carbohydrate. These nutrients in addition to transition metal ions can vary significantly between host environmental niches and infection stage. Since the pneumococcus must modulate CPS expression among various host niches during disease progression, we examined the impact of the nutritional transition metal availability of manganese (Mn) and zinc (Zn) on CPS production. We demonstrate that increased Mn/Zn ratios increase CPS production via Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway in a transcription-independent manner. Furthermore, we find that the downstream CPS protein CpsB, an Mn-dependent phosphatase, does not promote aberrant dephosphorylation of its target capsule-tyrosine kinase CpsD during Mn stress. Together, these data reveal a direct role for cellular Mn/Zn ratios in the regulation of CPS biosynthesis via the direct activation of Pgm. We propose a multilayer mechanism used by the pneumococcus in regulating CPS levels across various host niches. IMPORTANCE Evolving evidence strongly indicates that maintenance of metal homeostasis is essential for establishing colonization and continued growth of bacterial pathogens in the vertebrate host. In this study, we demonstrate the impact of cellular manganese/zinc (Mn/Zn) ratios on bacterial capsular polysaccharide (CPS) production, an important virulence determinant of many human-pathogenic bacteria, including Streptococcus pneumoniae. We show that higher Mn/Zn ratios increase CPS production via the Mn-dependent activation of the phosphoglucomutase Pgm, an enzyme that functions at the branch point between glycolysis and the CPS biosynthetic pathway. The findings provide a direct role for Mn/Zn homeostasis in the regulation of CPS expression levels and further support the ability of metal cations to act as important cellular signaling mediators in bacteria.
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28
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Zhang R, Shebes MA, Kho K, Scaffidi SJ, Meredith TC, Yu W. Spatial regulation of protein A in Staphylococcus aureus. Mol Microbiol 2021; 116:589-605. [PMID: 33949015 DOI: 10.1111/mmi.14734] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 12/31/2022]
Abstract
Surface proteins of Staphylococcus aureus play vital roles in bacterial physiology and pathogenesis. Recent work suggests that surface proteins are spatially regulated by a YSIRK/GXXS signal peptide that promotes cross-wall targeting at the mid-cell, though the mechanisms remain unclear. We previously showed that protein A (SpA), a YSIRK/GXXS protein and key staphylococcal virulence factor, mis-localizes in a ltaS mutant deficient in lipoteichoic acid (LTA) production. Here, we identified that SpA contains another cross-wall targeting signal, the LysM domain, which, in addition to the YSIRK/GXXS signal peptide, significantly enhances SpA cross-wall targeting. We show that LTA synthesis, but not LtaS, is required for SpA septal anchoring and cross-wall deposition. Interestingly, LTA is predominantly found at the peripheral cell membrane and is diminished at the septum of dividing staphylococcal cells, suggesting a restriction mechanism for SpA septal localization. Finally, we show that D-alanylation of LTA abolishes SpA cross-wall deposition by disrupting SpA distribution in the peptidoglycan layer without altering SpA septal anchoring. Our study reveals that multiple factors contribute to the spatial regulation and cross-wall targeting of SpA via different mechanisms, which coordinately ensures efficient incorporation of surface proteins into the growing peptidoglycan during the cell cycle.
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Affiliation(s)
- Ran Zhang
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Mac A Shebes
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Kelvin Kho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Salvatore J Scaffidi
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Wenqi Yu
- Department of Cell Biology, Microbiology and Molecular Biology (CMMB), University of South Florida, Tampa, FL, USA
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29
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Dong Y, Miao X, Zheng YD, Liu J, He QY, Ge R, Sun X. Ciprofloxacin-Resistant Staphylococcus aureus Displays Enhanced Resistance and Virulence in Iron-Restricted Conditions. J Proteome Res 2021; 20:2839-2850. [PMID: 33872026 DOI: 10.1021/acs.jproteome.1c00077] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The unreasonable misuse of antibiotics has led to the emergence of large-scale drug-resistant bacteria, seriously threatening human health. Compared with drug-sensitive bacteria, resistant bacteria are difficult to clear by host immunity. To fully explore the adaptive mechanism of resistant bacteria to the iron-restricted environment, we performed data-independent acquisition-based quantitative proteomics on ciprofloxacin (CIP)-resistant (CIP-R) Staphylococcus aureus in the presence or absence of iron. On bioinformatics analysis, CIP-R bacteria showed stronger amino acid synthesis and energy storage ability. Notably, CIP-R bacteria increased virulence by upregulating the expression of many virulence-related proteins and enhancing the synthesis of virulence-related amino acids under iron-restricted stress. This study will help us to further explain the adaptive mechanisms that lead to bacterial resistance to antibiotics depending on the host environment and provide insights into the development of novel drugs for the treatment of drug-resistant bacterial infections.
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Affiliation(s)
- Yingshan Dong
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Xinyu Miao
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Yun-Dan Zheng
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Jiajia Liu
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Qing-Yu He
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
| | - Ruiguang Ge
- State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Xuesong Sun
- MOE Key Laboratory of Tumor Molecular Biology and Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes, Institute of Life and Health Engineering, Jinan University, Guangzhou 510632, China
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30
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Fisher JF, Mobashery S. β-Lactams against the Fortress of the Gram-Positive Staphylococcus aureus Bacterium. Chem Rev 2021; 121:3412-3463. [PMID: 33373523 PMCID: PMC8653850 DOI: 10.1021/acs.chemrev.0c01010] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The biological diversity of the unicellular bacteria-whether assessed by shape, food, metabolism, or ecological niche-surely rivals (if not exceeds) that of the multicellular eukaryotes. The relationship between bacteria whose ecological niche is the eukaryote, and the eukaryote, is often symbiosis or stasis. Some bacteria, however, seek advantage in this relationship. One of the most successful-to the disadvantage of the eukaryote-is the small (less than 1 μm diameter) and nearly spherical Staphylococcus aureus bacterium. For decades, successful clinical control of its infection has been accomplished using β-lactam antibiotics such as the penicillins and the cephalosporins. Over these same decades S. aureus has perfected resistance mechanisms against these antibiotics, which are then countered by new generations of β-lactam structure. This review addresses the current breadth of biochemical and microbiological efforts to preserve the future of the β-lactam antibiotics through a better understanding of how S. aureus protects the enzyme targets of the β-lactams, the penicillin-binding proteins. The penicillin-binding proteins are essential enzyme catalysts for the biosynthesis of the cell wall, and understanding how this cell wall is integrated into the protective cell envelope of the bacterium may identify new antibacterials and new adjuvants that preserve the efficacy of the β-lactams.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
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31
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Streptococcus pneumoniae, S. mitis, and S. oralis Produce a Phosphatidylglycerol-Dependent, ltaS-Independent Glycerophosphate-Linked Glycolipid. mSphere 2021; 6:6/1/e01099-20. [PMID: 33627509 PMCID: PMC8544892 DOI: 10.1128/msphere.01099-20] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Lipoteichoic acid (LTA) is a Gram-positive bacterial cell surface polymer that participates in host-microbe interactions. It was previously reported that the major human pathogen Streptococcus pneumoniae and the closely related oral commensals S. mitis and S. oralis produce type IV LTAs. Herein, using liquid chromatography/mass spectrometry-based lipidomic analysis, we found that in addition to type IV LTA biosynthetic precursors, S. mitis, S. oralis, and S. pneumoniae also produce glycerophosphate (Gro-P)-linked dihexosyl (DH)-diacylglycerol (DAG), which is a biosynthetic precursor of type I LTA. cdsA and pgsA mutants produce DHDAG but lack (Gro-P)-DHDAG, indicating that the Gro-P moiety is derived from phosphatidylglycerol (PG), whose biosynthesis requires these genes. S. mitis, but not S. pneumoniae or S. oralis, encodes an ortholog of the PG-dependent type I LTA synthase, ltaS. By heterologous expression analyses, we confirmed that S. mitisltaS confers poly(Gro-P) synthesis in both Escherichia coli and Staphylococcus aureus and that S. mitisltaS can rescue the growth defect of an S. aureusltaS mutant. However, we do not detect a poly(Gro-P) polymer in S. mitis using an anti-type I LTA antibody. Moreover, Gro-P-linked DHDAG is still synthesized by an S. mitisltaS mutant, demonstrating that S. mitis LtaS does not catalyze Gro-P transfer to DHDAG. Finally, an S. mitisltaS mutant has increased sensitivity to human serum, demonstrating that ltaS confers a beneficial but currently undefined function in S. mitis. Overall, our results demonstrate that S. mitis, S. pneumoniae, and S. oralis produce a Gro-P-linked glycolipid via a PG-dependent, ltaS-independent mechanism. IMPORTANCE The cell wall is a critical structural component of bacterial cells that confers important physiological functions. For pathogens, it is a site of host-pathogen interactions. In this work, we analyze the glycolipids synthesized by the mitis group streptococcal species, S. pneumoniae, S. oralis, and S. mitis. We find that all produce the glycolipid, glycerophosphate (Gro-P)-linked dihexosyl (DH)-diacylglycerol (DAG), which is a precursor for the cell wall polymer type I lipoteichoic acid in other bacteria. We investigate whether the known enzyme for type I LTA synthesis, LtaS, plays a role in synthesizing this molecule in S. mitis. Our results indicate that a novel mechanism is responsible. Our results are significant because they identify a novel feature of S. pneumoniae, S. oralis, and S. mitis glycolipid biology.
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32
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Modifications of cell wall polymers in Gram-positive bacteria by multi-component transmembrane glycosylation systems. Curr Opin Microbiol 2021; 60:24-33. [PMID: 33578058 PMCID: PMC8035078 DOI: 10.1016/j.mib.2021.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/12/2021] [Accepted: 01/22/2021] [Indexed: 11/22/2022]
Abstract
Secondary cell wall polymers fulfil diverse and important functions within the cell wall of Gram-positive bacteria. Here, we will provide a brief overview of the principles of teichoic acid and complex secondary cell wall polysaccharide biosynthesis pathways in Firmicutes and summarize the recently revised mechanism for the decoration of teichoic acids with d-alanines. Many cell wall polymers are decorated with glycosyl groups, either intracellularly or extracellularly. The main focus of this review will be on the extracellular glycosylation mechanism and recent advances that have been made in the identification of enzymes involved in this process. Based on the proteins involved, we propose to rename the system to multi-component transmembrane glycosylation system in place of three-component glycosylation system.
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33
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Mikkelsen K, Sirisarn W, Alharbi O, Alharbi M, Liu H, Nøhr-Meldgaard K, Mayer K, Vestergaard M, Gallagher LA, Derrick JP, McBain AJ, Biboy J, Vollmer W, O'Gara JP, Grunert T, Ingmer H, Xia G. The Novel Membrane-Associated Auxiliary Factors AuxA and AuxB Modulate β-lactam Resistance in MRSA by stabilizing Lipoteichoic Acids. Int J Antimicrob Agents 2021; 57:106283. [PMID: 33503451 DOI: 10.1016/j.ijantimicag.2021.106283] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/08/2020] [Accepted: 12/19/2020] [Indexed: 01/20/2023]
Abstract
A major determinant of β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) is the drug insensitive transpeptidase, PBP2a, encoded by mecA. Full expression of the resistance phenotype requires auxiliary factors. Two such factors, auxiliary factor A (auxA, SAUSA300_0980) and B (auxB, SAUSA300_1003), were identified in a screen against mutants with increased susceptibility to β-lactams in the MRSA strain, JE2. auxA and auxB encode transmembrane proteins, with AuxA predicted to be a transporter. Inactivation of auxA or auxB enhanced β-lactam susceptibility in community-, hospital- and livestock-associated MRSA strains without affecting PBP2a expression, peptidoglycan cross-linking or wall teichoic acid synthesis. Both mutants displayed increased susceptibility to inhibitors of lipoteichoic acid (LTA) synthesis and alanylation pathways and released LTA even in the absence of β-lactams. The β-lactam susceptibility of the aux mutants was suppressed by mutations inactivating gdpP, which was previously found to allow growth of mutants lacking the lipoteichoic synthase enzyme, LtaS. Using the Galleria mellonella infection model, enhanced survival of larvae inoculated with either auxA or auxB mutants was observed compared with the wild-type strain following treatment with amoxicillin. These results indicate that AuxA and AuxB are central for LTA stability and potential inhibitors can be tools to re-sensitize MRSA strains to β-lactams and combat MRSA infections.
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Affiliation(s)
- Kasper Mikkelsen
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Wanchat Sirisarn
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Ohood Alharbi
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Mohanned Alharbi
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Huayong Liu
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | | | - Katharina Mayer
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Martin Vestergaard
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark
| | - Laura A Gallagher
- Department of Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Jeremy P Derrick
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom
| | - Andrew J McBain
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, United Kingdom
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, NU Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, NU Biosciences Institute, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - James P O'Gara
- Department of Microbiology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Tom Grunert
- Functional Microbiology, Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Hanne Ingmer
- Department of Veterinary and Animal Sciences, University of Copenhagen, Denmark.
| | - Guoqing Xia
- Lydia Becker Institute of Immunology and Inflammation, Division of Infection, Immunity and Respiratory Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, M13 9PT, United Kingdom.
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Lipoteichoic acid polymer length is determined by competition between free starter units. Proc Natl Acad Sci U S A 2020; 117:29669-29676. [PMID: 33172991 DOI: 10.1073/pnas.2008929117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Carbohydrate polymers exhibit incredible chemical and structural diversity, yet are produced by polymerases without a template to guide length and composition. As the length of carbohydrate polymers is critical for their biological functions, understanding the mechanisms that determine polymer length is an important area of investigation. Most Gram-positive bacteria produce anionic glycopolymers called lipoteichoic acids (LTA) that are synthesized by lipoteichoic acid synthase (LtaS) on a diglucosyl-diacylglycerol (Glc2DAG) starter unit embedded in the extracellular leaflet of the cell membrane. LtaS can use phosphatidylglycerol (PG) as an alternative starter unit, but PG-anchored LTA polymers are significantly longer, and cells that make these abnormally long polymers exhibit major defects in cell growth and division. To determine how LTA polymer length is controlled, we reconstituted Staphylococcus aureus LtaS in vitro. We show that polymer length is an intrinsic property of LtaS that is directly regulated by the identity and concentration of lipid starter units. Polymerization is processive, and the overall reaction rate is substantially faster for the preferred Glc2DAG starter unit, yet the use of Glc2DAG leads to shorter polymers. We propose a simple mechanism to explain this surprising result: free starter units terminate polymerization by displacing the lipid anchor of the growing polymer from its binding site on the enzyme. Because LtaS is conserved across most Gram-positive bacteria and is important for survival, this reconstituted system should be useful for characterizing inhibitors of this key cell envelope enzyme.
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Ranganathan N, Johnson R, Edwards AM. The general stress response of Staphylococcus aureus promotes tolerance of antibiotics and survival in whole human blood. MICROBIOLOGY (READING, ENGLAND) 2020; 166:1088-1094. [PMID: 33095698 PMCID: PMC7723259 DOI: 10.1099/mic.0.000983] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 10/06/2020] [Indexed: 12/29/2022]
Abstract
Staphylococcus aureus is a frequent cause of invasive human infections such as bacteraemia and infective endocarditis. These infections frequently relapse or become chronic, suggesting that the pathogen has mechanisms to tolerate the twin threats of therapeutic antibiotics and host immunity. The general stress response of S. aureus is regulated by the alternative sigma factor B (σB) and provides protection from multiple stresses including oxidative, acidic and heat. σB also contributes to virulence, intracellular persistence and chronic infection. However, the protective effect of σB on bacterial survival during exposure to antibiotics or host immune defences is poorly characterized. We found that σB promotes the survival of S. aureus exposed to the antibiotics gentamicin, ciprofloxacin, vancomycin and daptomycin, but not oxacillin or clindamycin. We also found that σB promoted staphylococcal survival in whole human blood, most likely via its contribution to oxidative stress resistance. Therefore, we conclude that the general stress response of S. aureus may contribute to the development of chronic infection by conferring tolerance to both antibiotics and host immune defences.
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Affiliation(s)
- Nisha Ranganathan
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London, SW7 2AZ, UK
- Present address: Charing Cross Hospital, Fulham, Palace Road, W6 8RF, UK
| | - Rebecca Johnson
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London, SW7 2AZ, UK
- Present address: Horizon Discovery, Waterbeach, Cambridge, CB25 9TL, UK
| | - Andrew M. Edwards
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, Armstrong Rd, London, SW7 2AZ, UK
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Cell morphology maintenance in Bacillus subtilis through balanced peptidoglycan synthesis and hydrolysis. Sci Rep 2020; 10:17910. [PMID: 33087775 PMCID: PMC7578834 DOI: 10.1038/s41598-020-74609-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/28/2020] [Indexed: 01/12/2023] Open
Abstract
The peptidoglycan layer is responsible for maintaining bacterial cell shape and permitting cell division. Cell wall growth is facilitated by peptidoglycan synthases and hydrolases and is potentially modulated by components of the central carbon metabolism. In Bacillus subtilis, UgtP synthesises the glucolipid precursor for lipoteichoic acid and has been suggested to function as a metabolic sensor governing cell size. Here we show that ugtP mutant cells have increased levels of cell wall precursors and changes in their peptidoglycan that suggest elevated DL-endopeptidase activity. The additional deletion of lytE, encoding a DL-endopeptidase important for cell elongation, in the ugtP mutant background produced cells with severe shape defects. Interestingly, the ugtP lytE mutant recovered normal rod-shape by acquiring mutations that decreased the expression of the peptidoglycan synthase PBP1. Together our results suggest that cells lacking ugtP must re-adjust the balance between peptidoglycan synthesis and hydrolysis to maintain proper cell morphology.
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Willing S, Dyer E, Schneewind O, Missiakas D. FmhA and FmhC of Staphylococcus aureus incorporate serine residues into peptidoglycan cross-bridges. J Biol Chem 2020; 295:13664-13676. [PMID: 32759309 PMCID: PMC7521636 DOI: 10.1074/jbc.ra120.014371] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/03/2020] [Indexed: 12/16/2022] Open
Abstract
Staphylococcal peptidoglycan is characterized by pentaglycine cross-bridges that are cross-linked between adjacent wall peptides by penicillin-binding proteins to confer robustness and flexibility. In Staphylococcus aureus, pentaglycine cross-bridges are synthesized by three proteins: FemX adds the first glycine, and the homodimers FemA and FemB sequentially add two Gly-Gly dipeptides. Occasionally, serine residues are also incorporated into the cross-bridges by enzymes that have heretofore not been identified. Here, we show that the FemA/FemB homologues FmhA and FmhC pair with FemA and FemB to incorporate Gly-Ser dipeptides into cross-bridges and to confer resistance to lysostaphin, a secreted bacteriocin that cleaves the pentaglycine cross-bridge. FmhA incorporates serine residues at positions 3 and 5 of the cross-bridge. In contrast, FmhC incorporates a single serine at position 5. Serine incorporation also lowers resistance toward oxacillin, an antibiotic that targets penicillin-binding proteins, in both methicillin-sensitive and methicillin-resistant strains of S. aureus FmhC is encoded by a gene immediately adjacent to lytN, which specifies a hydrolase that cleaves the bond between the fifth glycine of cross-bridges and the alanine of the adjacent stem peptide. In this manner, LytN facilitates the separation of daughter cells. Cell wall damage induced upon lytN overexpression can be alleviated by overexpression of fmhC. Together, these observations suggest that FmhA and FmhC generate peptidoglycan cross-bridges with unique serine patterns that provide protection from endogenous murein hydrolases governing cell division and from bacteriocins produced by microbial competitors.
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Affiliation(s)
- Stephanie Willing
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Emma Dyer
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Dominique Missiakas
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA; Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA.
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Schneider R, Primon-Barros M, Von Borowski RG, Chat S, Nonin-Lecomte S, Gillet R, Macedo AJ. Pseudonajide peptide derived from snake venom alters cell envelope integrity interfering on biofilm formation in Staphylococcus epidermidis. BMC Microbiol 2020; 20:237. [PMID: 32746783 PMCID: PMC7397659 DOI: 10.1186/s12866-020-01921-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
Background The increase in bacterial resistance phenotype cases is a global health problem. New strategies must be explored by the scientific community in order to create new treatment alternatives. Animal venoms are a good source for antimicrobial peptides (AMPs), which are excellent candidates for new antimicrobial drug development. Cathelicidin-related antimicrobial peptides (CRAMPs) from snake venoms have been studied as a model for the design of new antimicrobial pharmaceuticals against bacterial infections. Results In this study we present an 11 amino acid-long peptide, named pseudonajide, which is derived from a Pseudonaja textilis venom peptide and has antimicrobial and antibiofilm activity against Staphylococcus epidermidis. Pseudonajide was selected based on the sequence alignments of various snake venom peptides that displayed activity against bacteria. Antibiofilm activity assays with pseudonajide concentrations ranging from 3.12 to 100 μM showed that the lowest concentration to inhibit biofilm formation was 25 μM. Microscopy analysis demonstrated that pseudonajide interacts with the bacterial cell envelope, disrupting the cell walls and membranes, leading to morphological defects in prokaryotes. Conclusions Our results suggest that pseudonajide’s positives charges interact with negatively charged cell wall components of S. epidermidis, leading to cell damage and inhibiting biofilm formation.
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Affiliation(s)
- Rafael Schneider
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, Rennes, France.,Laboratório de Biofilmes e Diversidade Microbiana, Faculdade de Farmácia and Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Muriel Primon-Barros
- Laboratório de Biofilmes e Diversidade Microbiana, Faculdade de Farmácia and Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Rafael Gomes Von Borowski
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, Rennes, France.,Laboratório de Biofilmes e Diversidade Microbiana, Faculdade de Farmácia and Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Sophie Chat
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, Rennes, France
| | - Sylvie Nonin-Lecomte
- Faculté de Pharmacie, Université de Paris, CNRS, CiTCoM, UMR 8038, Paris, France
| | - Reynald Gillet
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, Rennes, France.
| | - Alexandre José Macedo
- Laboratório de Biofilmes e Diversidade Microbiana, Faculdade de Farmácia and Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
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Hesser AR, Matano LM, Vickery CR, Wood BM, Santiago AG, Morris HG, Do T, Losick R, Walker S. The length of lipoteichoic acid polymers controls Staphylococcus aureus cell size and envelope integrity. J Bacteriol 2020; 202:JB.00149-20. [PMID: 32482719 PMCID: PMC8404710 DOI: 10.1128/jb.00149-20] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/22/2020] [Indexed: 02/08/2023] Open
Abstract
The opportunistic pathogen Staphylococcus aureus is protected by a cell envelope that is crucial for viability. In addition to peptidoglycan, lipoteichoic acid (LTA) is an especially important component of the S. aureus cell envelope. LTA is an anionic polymer anchored to a glycolipid in the outer leaflet of the cell membrane. It was known that deleting the gene for UgtP, the enzyme that makes this glycolipid anchor, causes cell growth and division defects. In Bacillus subtilis, growth abnormalities from the loss of ugtP have been attributed to both the absence of the encoded protein and to the loss of its products. Here, we show that growth defects in S. aureus ugtP deletion mutants are due to the long, abnormal LTA polymer that is produced when the glycolipid anchor is missing from the outer leaflet of the membrane. Dysregulated cell growth leads to defective cell division, and these phenotypes are corrected by mutations in the LTA polymerase, ltaS, that reduce polymer length. We also show that S. aureus mutants with long LTA are sensitized to cell wall hydrolases, beta-lactam antibiotics, and compounds that target other cell envelope pathways. We conclude that control of LTA polymer length is important for S. aureus physiology and promotes survival under stressful conditions, including antibiotic stress.IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of community- and hospital-acquired infections and is responsible for a large fraction of deaths caused by antibiotic-resistant bacteria. S. aureus is surrounded by a complex cell envelope that protects it from antimicrobial compounds and other stresses. Here we show that controlling the length of an essential cell envelope polymer, lipoteichoic acid, is critical for controlling S. aureus cell size and cell envelope integrity. We also show that genes involved in LTA length regulation are required for resistance to beta-lactam antibiotics in MRSA. The proteins encoded by these genes may be targets for combination therapy with an appropriate beta-lactam.
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Affiliation(s)
- Anthony R Hesser
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Leigh M Matano
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | | | - B McKay Wood
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Ace George Santiago
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Heidi G Morris
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Truc Do
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Richard Losick
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
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Zhang B, Liu X, Lambert E, Mas G, Hiller S, Veening JW, Perez C. Structure of a proton-dependent lipid transporter involved in lipoteichoic acids biosynthesis. Nat Struct Mol Biol 2020; 27:561-569. [PMID: 32367070 DOI: 10.1038/s41594-020-0425-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 03/30/2020] [Indexed: 01/09/2023]
Abstract
Lipoteichoic acids (LTAs) are essential cell-wall components in Gram-positive bacteria, including the human pathogen Staphylococcus aureus, contributing to cell adhesion, cell division and antibiotic resistance. Genetic evidence has suggested that LtaA is the flippase that mediates the translocation of the lipid-linked disaccharide that anchors LTA to the cell membrane, a rate-limiting step in S. aureus LTA biogenesis. Here, we present the structure of LtaA, describe its flipping mechanism and show its functional relevance for S. aureus fitness. We demonstrate that LtaA is a proton-coupled antiporter flippase that contributes to S. aureus survival under physiological acidic conditions. Our results provide foundations for the development of new strategies to counteract S. aureus infections.
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Affiliation(s)
- Bing Zhang
- Biozentrum, University of Basel, Basel, Switzerland
| | - Xue Liu
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | | | | | | | - Jan-Willem Veening
- Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Camilo Perez
- Biozentrum, University of Basel, Basel, Switzerland.
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41
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Jeong DW, Lee B, Heo S, Oh Y, Heo G, Lee JH. Two genes involved in clindamycin resistance of Bacillus licheniformis and Bacillus paralicheniformis identified by comparative genomic analysis. PLoS One 2020; 15:e0231274. [PMID: 32271828 PMCID: PMC7144989 DOI: 10.1371/journal.pone.0231274] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/19/2020] [Indexed: 11/19/2022] Open
Abstract
We evaluated the minimum inhibitory concentrations of clindamycin and erythromycin toward 98 Bacillus licheniformis strains isolated from several types of fermented soybean foods manufactured in several districts of Korea. First, based on recent taxonomic standards for bacteria, the 98 strains were separated into 74 B. licheniformis strains and 24 B. paralicheniformis strains. Both species exhibited profiles of erythromycin resistance as an acquired characteristic. B. licheniformis strains exhibited acquired clindamycin resistance, while B. paralicheniformis strains showed unimodal clindamycin resistance, indicating an intrinsic characteristic. Comparative genomic analysis of five strains showing three different patterns of clindamycin and erythromycin resistance identified 23S rRNA (adenine 2058-N6)-dimethyltransferase gene ermC and spermidine acetyltransferase gene speG as candidates potentially involved in clindamycin resistance. Functional analysis of these genes using B. subtilis as a host showed that ermC contributes to cross-resistance to clindamycin and erythromycin, and speG confers resistance to clindamycin. ermC is located in the chromosomes of strains showing clindamycin and erythromycin resistance and no transposable element was identified in its flanking regions. The acquisition of ermC might be attributable to a homologous recombination. speG was identified in not only the five genome-analyzed strains but also eight strains randomly selected from the 98 test strains, and deletions in the structural gene or putative promoter region caused clindamycin sensitivity, which supports the finding that the clindamycin resistance of Bacillus species is an intrinsic property.
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Affiliation(s)
- Do-Won Jeong
- Department of Food and Nutrition, Dongduk Women’s University, Seoul, Republic of Korea
| | - Byunghoon Lee
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, Republic of Korea
| | - Sojeong Heo
- Department of Food and Nutrition, Dongduk Women’s University, Seoul, Republic of Korea
| | - Yeongmin Oh
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, Republic of Korea
| | - Ganghun Heo
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, Republic of Korea
| | - Jong-Hoon Lee
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, Republic of Korea
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Rismondo J, Haddad TFM, Shen Y, Loessner MJ, Gründling A. GtcA is required for LTA glycosylation in Listeria monocytogenes serovar 1/2a and Bacillus subtilis. ACTA ACUST UNITED AC 2020; 6:100038. [PMID: 32743150 PMCID: PMC7389260 DOI: 10.1016/j.tcsw.2020.100038] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/16/2020] [Accepted: 02/11/2020] [Indexed: 11/26/2022]
Abstract
The cell wall polymers wall teichoic acid (WTA) and lipoteichoic acid (LTA) are often modified with glycosyl and D-alanine residues. Recent studies have shown that a three-component glycosylation system is used for the modification of LTA in several Gram-positive bacteria including Bacillus subtilis and Listeria monocytogenes. In the L. monocytogenes 1/2a strain 10403S, the cytoplasmic glycosyltransferase GtlA is thought to use UDP-galactose to produce the C55-P-galactose lipid intermediate, which is transported across the membrane by an unknown flippase. Next, the galactose residue is transferred onto the LTA backbone on the outside of the cell by the glycosyltransferase GtlB. Here we show that GtcA is necessary for the glycosylation of LTA in L. monocytogenes 10403S and B. subtilis 168 and we hypothesize that these proteins act as C55-P-sugar flippases. With this we revealed that GtcA is involved in the glycosylation of both teichoic acid polymers in L. monocytogenes 10403S, namely WTA with N-acetylglucosamine and LTA with galactose residues. These findings indicate that the L. monocytogenes GtcA protein can act on different C55-P-sugar intermediates. Further characterization of GtcA in L. monocytogenes led to the identification of residues essential for its overall function as well as residues, which predominately impact WTA or LTA glycosylation.
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Affiliation(s)
- Jeanine Rismondo
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Talal F M Haddad
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Yang Shen
- Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland
| | - Martin J Loessner
- Institute of Food, Nutrition and Health, ETH Zurich, 8092 Zurich, Switzerland
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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Zeden MS, Kviatkovski I, Schuster CF, Thomas VC, Fey PD, Gründling A. Identification of the main glutamine and glutamate transporters in Staphylococcus aureus and their impact on c-di-AMP production. Mol Microbiol 2020; 113:1085-1100. [PMID: 31997474 PMCID: PMC7299772 DOI: 10.1111/mmi.14479] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/22/2020] [Indexed: 12/19/2022]
Abstract
A Staphylococcus aureus strain deleted for the c‐di‐AMP cyclase gene dacA is unable to survive in rich medium unless it acquires compensatory mutations. Previously identified mutations were in opuD, encoding the main glycine‐betaine transporter, and alsT, encoding a predicted amino acid transporter. Here, we show that inactivation of OpuD restores the cell size of a dacA mutant to near wild‐type (WT) size, while inactivation of AlsT does not. AlsT was identified as an efficient glutamine transporter, indicating that preventing glutamine uptake in rich medium rescues the growth of the S. aureus dacA mutant. In addition, GltS was identified as a glutamate transporter. By performing growth curves with WT, alsT and gltS mutant strains in defined medium supplemented with ammonium, glutamine or glutamate, we revealed that ammonium and glutamine, but not glutamate promote the growth of S. aureus. This suggests that besides ammonium also glutamine can serve as a nitrogen source under these conditions. Ammonium and uptake of glutamine via AlsT and hence likely a higher intracellular glutamine concentration inhibited c‐di‐AMP production, while glutamate uptake had no effect. These findings provide, besides the previously reported link between potassium and osmolyte uptake, a connection between nitrogen metabolism and c‐di‐AMP signalling in S. aureus.
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Affiliation(s)
- Merve S Zeden
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Igor Kviatkovski
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Christopher F Schuster
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Vinai C Thomas
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Angelika Gründling
- Section of Molecular Microbiology, Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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Schuster CF, Wiedemann DM, Kirsebom FCM, Santiago M, Walker S, Gründling A. High-throughput transposon sequencing highlights the cell wall as an important barrier for osmotic stress in methicillin resistant Staphylococcus aureus and underlines a tailored response to different osmotic stressors. Mol Microbiol 2019; 113:699-717. [PMID: 31770461 PMCID: PMC7176532 DOI: 10.1111/mmi.14433] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 11/24/2019] [Indexed: 12/28/2022]
Abstract
Staphylococcus aureus is an opportunistic pathogen that can cause soft tissue infections but is also a frequent cause of foodborne illnesses. One contributing factor for this food association is its high salt tolerance allowing this organism to survive commonly used food preservation methods. How this resistance is mediated is poorly understood, particularly during long-term exposure. In this study, we used transposon sequencing (TN-seq) to understand how the responses to osmotic stressors differ. Our results revealed distinctly different long-term responses to NaCl, KCl and sucrose stresses. In addition, we identified the DUF2538 domain containing gene SAUSA300_0957 (gene 957) as essential under salt stress. Interestingly, a 957 mutant was less susceptible to oxacillin and showed increased peptidoglycan crosslinking. The salt sensitivity phenotype could be suppressed by amino acid substitutions in the transglycosylase domain of the penicillin-binding protein Pbp2, and these changes restored the peptidoglycan crosslinking to WT levels. These results indicate that increased crosslinking of the peptidoglycan polymer can be detrimental and highlight a critical role of the bacterial cell wall for osmotic stress resistance. This study will serve as a starting point for future research on osmotic stress response and help develop better strategies to tackle foodborne staphylococcal infections.
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Affiliation(s)
- Christopher F Schuster
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - David M Wiedemann
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Freja C M Kirsebom
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Marina Santiago
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA
| | - Angelika Gründling
- Section of Molecular Microbiology and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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Lima BP, Kho K, Nairn BL, Davies JR, Svensäter G, Chen R, Steffes A, Vreeman GW, Meredith TC, Herzberg MC. Streptococcus gordonii Type I Lipoteichoic Acid Contributes to Surface Protein Biogenesis. mSphere 2019; 4:e00814-19. [PMID: 31801844 PMCID: PMC6893214 DOI: 10.1128/msphere.00814-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/18/2022] Open
Abstract
Lipoteichoic acid (LTA) is an abundant polymer of the Gram-positive bacterial cell envelope and is essential for many species. Whereas the exact function of LTA has not been elucidated, loss of LTA in some species affects hydrophobicity, biofilm formation, and cell division. Using a viable LTA-deficient strain of the human oral commensal Streptococcus gordonii, we demonstrated that LTA plays an important role in surface protein presentation. Cell wall fractions derived from the wild-type and LTA-deficient strains of S. gordonii were analyzed using label-free mass spectroscopy. Comparisons showed that the abundances of many proteins differed, including (i) SspA, SspB, and S. gordonii 0707 (SGO_0707) (biofilm formation); (ii) FtsE (cell division); (iii) Pbp1a and Pbp2a (cell wall biosynthesis and remodeling); and (iv) DegP (envelope stress response). These changes in cell surface protein presentation appear to explain our observations of altered cell envelope homeostasis, biofilm formation, and adhesion to eukaryotic cells, without affecting binding and coaggregation with other bacterial species, and provide insight into the phenotypes revealed by the loss of LTA in other species of Gram-positive bacteria. We also characterized the chemical structure of the LTA expressed by S. gordonii Similarly to Streptococcus suis, S. gordonii produced a complex type I LTA, decorated with multiple d-alanylations and glycosylations. Hence, the S. gordonii LTA appears to orchestrate expression and presentation of cell surface-associated proteins and functions.IMPORTANCE Discovered over a half-century ago, lipoteichoic acid (LTA) is an abundant polymer found on the surface of Gram-positive bacteria. Although LTA is essential for the survival of many Gram-positive species, knowledge of how LTA contributes to bacterial physiology has remained elusive. Recently, LTA-deficient strains have been generated in some Gram-positive species, including the human oral commensal Streptococcus gordonii The significance of our research is that we utilized an LTA-deficient strain of S. gordonii to address why LTA is physiologically important to Gram-positive bacteria. We demonstrate that in S. gordonii, LTA plays an important role in the presentation of many cell surface-associated proteins, contributing to cell envelope homeostasis, cell-to-cell interactions in biofilms, and adhesion to eukaryotic cells. These data may broadly reflect a physiological role of LTA in Gram-positive bacteria.
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Affiliation(s)
- Bruno P Lima
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kelvin Kho
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Brittany L Nairn
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julia R Davies
- Department of Oral Biology, Faculty of Odontology, Malmo University, Malmo, Sweden
| | - Gunnel Svensäter
- Department of Oral Biology, Faculty of Odontology, Malmo University, Malmo, Sweden
| | - Ruoqiong Chen
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Amanda Steffes
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gerrit W Vreeman
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, State College, Pennsylvania, USA
| | - Mark C Herzberg
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
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46
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Coe KA, Lee W, Stone MC, Komazin-Meredith G, Meredith TC, Grad YH, Walker S. Multi-strain Tn-Seq reveals common daptomycin resistance determinants in Staphylococcus aureus. PLoS Pathog 2019; 15:e1007862. [PMID: 31738809 PMCID: PMC6934316 DOI: 10.1371/journal.ppat.1007862] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 12/27/2019] [Accepted: 09/24/2019] [Indexed: 01/30/2023] Open
Abstract
Antibiotic-resistant Staphylococcus aureus remains a leading cause of antibiotic resistance-associated mortality in the United States. Given the reality of multi-drug resistant infections, it is imperative that we establish and maintain a pipeline of new compounds to replace or supplement our current antibiotics. A first step towards this goal is to prioritize targets by identifying the genes most consistently required for survival across the S. aureus phylogeny. Here we report the first direct comparison of multiple strains of S. aureus via transposon sequencing. We show that mutant fitness varies by strain in key pathways, underscoring the importance of using more than one strain to differentiate between core and strain-dependent essential genes. We treated the libraries with daptomycin to assess whether the strain-dependent differences impact pathways important for survival. Despite baseline differences in gene importance, several pathways, including the lipoteichoic acid pathway, consistently promote survival under daptomycin exposure, suggesting core vulnerabilities that can be exploited to resensitize daptomycin-nonsusceptible isolates. We also demonstrate the merit of using transposons with outward-facing promoters capable of overexpressing nearby genes for identifying clinically-relevant gain-of-function resistance mechanisms. Together, the daptomycin vulnerabilities and resistance mechanisms support a mode of action with wide-ranging effects on the cell envelope and cell division. This work adds to a growing body of literature demonstrating the nuanced insights gained by comparing Tn-Seq results across multiple bacterial strains. Antibiotic-resistant Staphylococcus aureus kills thousands of people every year in the United States alone. To stay ahead of the looming threat of multidrug-resistant infections, we must continue to develop new antibiotics and find ways to make our current repertoire of antibiotics more effective, including by finding pairs of compounds that perform best when administered together. In the age of next-generation sequencing, we can now use transposon sequencing to find potential targets for new antibiotics on a genome-wide scale, identified as either essential genes or genes that positively influence survival in the presence of an antibiotic. In this work, we created a compendium of genes that are essential across a range of S. aureus strains, as well as those that are important for growth in the presence of the antibiotic daptomycin. The results will be a resource for researchers working to develop the next generation of antibiotic therapies.
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Affiliation(s)
- Kathryn A. Coe
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Wonsik Lee
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
- School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea
| | - Madeleine C. Stone
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Gloria Komazin-Meredith
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania, United States of America
| | - Timothy C. Meredith
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, Pennsylvania, United States of America
- * E-mail: (TCM); (YHG); (SW)
| | - Yonatan H. Grad
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Division of Infectious Diseases, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (TCM); (YHG); (SW)
| | - Suzanne Walker
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, United States of America
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, United States of America
- * E-mail: (TCM); (YHG); (SW)
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RexAB is essential for the mutagenic repair of Staphylococcus aureus DNA damage caused by co-trimoxazole. Antimicrob Agents Chemother 2019:AAC.00944-19. [PMID: 31591116 PMCID: PMC6879246 DOI: 10.1128/aac.00944-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Co-trimoxazole (SXT) is a combination therapeutic that consists of sulfamethoxazole and trimethoprim that is increasingly used to treat skin and soft-tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA). However, the use of SXT is limited to the treatment of low-burden, superficial S. aureus infections and its therapeutic value is compromised by the frequent emergence of resistance. As a first step towards the identification of approaches to enhance the efficacy of SXT, we examined the role of bacterial DNA repair in antibiotic susceptibility and mutagenesis. We found that mutants lacking the DNA repair complex RexAB had a modest 2-fold lower SXT MIC than wild-type strains but were killed 50-5000-fold more efficiently by the combination antibiotic at the breakpoint concentration. SXT-mediated DNA damage occurred via both thymidine limitation and the generation of reactive oxygen species, and triggered induction of the SOS response in a RexAB-dependent manner. SOS induction was associated with a 50% increase in the mutation rate, which may contribute to emergence of resistant strains during SXT therapy. In summary, this work determined that SXT caused DNA damage in S. aureus via both thymidine limitation and oxidative stress, which was repaired by the RexAB complex, leading to induction of the mutagenic SOS response. Small molecule inhibitors of RexAB could therefore have therapeutic value by increasing the efficacy of SXT and decreasing the emergence of drug-resistance during treatment of infections caused by S. aureus.
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48
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Patel V, Black KA, Rhee KY, Helmann JD. Bacillus subtilis PgcA moonlights as a phosphoglucosamine mutase in support of peptidoglycan synthesis. PLoS Genet 2019; 15:e1008434. [PMID: 31589605 PMCID: PMC6797236 DOI: 10.1371/journal.pgen.1008434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 10/17/2019] [Accepted: 09/18/2019] [Indexed: 01/25/2023] Open
Abstract
Phosphohexomutase superfamily enzymes catalyze the reversible intramolecular transfer of a phosphoryl moiety on hexose sugars. Bacillus subtilis phosphoglucomutase PgcA catalyzes the reversible interconversion of glucose 6-phosphate (Glc-6-P) and glucose 1-phosphate (Glc-1-P), a precursor of UDP-glucose (UDP-Glc). B. subtilis phosphoglucosamine mutase (GlmM) is a member of the same enzyme superfamily that converts glucosamine 6-phosphate (GlcN-6-P) to glucosamine 1-phosphate (GlcN-1-P), a precursor of the amino sugar moiety of peptidoglycan. Here, we present evidence that B. subtilis PgcA possesses activity as a phosphoglucosamine mutase that contributes to peptidoglycan biosynthesis. This activity was made genetically apparent by the synthetic lethality of pgcA with glmR, a positive regulator of amino sugar biosynthesis, which can be specifically suppressed by overproduction of GlmM. A gain-of-function mutation in a substrate binding loop (PgcA G47S) increases this secondary activity and suppresses a glmR mutant. Our results demonstrate that bacterial phosphoglucomutases may possess secondary phosphoglucosamine mutase activity, and that this dual activity may provide some level of functional redundancy for the essential peptidoglycan biosynthesis pathway.
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Affiliation(s)
- Vaidehi Patel
- Department of Microbiology, Cornell University, Ithaca, NY, United States of America
| | - Katherine A. Black
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, NY, United States of America
| | - Kyu Y. Rhee
- Division of Infectious Diseases, Weill Department of Medicine, Weill Cornell Medicine, New York, NY, United States of America
| | - John D. Helmann
- Department of Microbiology, Cornell University, Ithaca, NY, United States of America
- * E-mail:
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49
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Swain J, El Khoury M, Flament A, Dezanet C, Briée F, Van Der Smissen P, Décout JL, Mingeot-Leclercq MP. Antimicrobial activity of amphiphilic neamine derivatives: Understanding the mechanism of action on Gram-positive bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:182998. [DOI: 10.1016/j.bbamem.2019.05.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 05/22/2019] [Accepted: 05/28/2019] [Indexed: 01/06/2023]
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50
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Wu X, Song Q, Han A. Interacting proteins of the essential two-component system YycFG in Bacillus subtilis. J Basic Microbiol 2019; 59:950-959. [PMID: 31339578 DOI: 10.1002/jobm.201800701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/14/2019] [Accepted: 06/24/2019] [Indexed: 11/06/2022]
Abstract
Two-component signal transduction systems (TCSs) play a major role in adaption and survival of microorganisms in a dynamic and sometimes dangerous environment. YycFG is an essential TCS for many Gram-positive bacteria, such as Bacillus subtilis, which regulates many important biological processes. However, its functional essentiality remains largely unknown. Here, we report several YycFG interacting proteins through coimmunoprecipitation (Co-IP) and mass spectrometry (MS) analyses. We engineered the B. subtilis genome by a knock-in approach to express YycG with a C-terminal Flag and YycF with an N-terminal HA tag. Immunoprecipitated fractions using anti-Flag or anti-HA agarose were subjected to MS analyses. A total of 41 YycG interacting proteins and four YycF interacting proteins were identified, most of which are involved in cellular metabolic processes, including cell wall synthesis and modification. The interactions of YycG with AsnB and FabL, as examples, were further validated in vitro. This study provided a clue that YycFG may be directly involved in regulation of bacterial central metabolic pathways.
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Affiliation(s)
- Xuanang Wu
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China
| | - Qi Song
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China
| | - Aidong Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiang'an, Xiamen, China
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