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Bogut A, Koper P, Marczak M, Całka P. The first genomic characterization of a stable, hemin-dependent small colony variant strain of Staphylococcus epidermidis isolated from a prosthetic-joint infection. Front Microbiol 2023; 14:1289844. [PMID: 37928677 PMCID: PMC10620731 DOI: 10.3389/fmicb.2023.1289844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 10/05/2023] [Indexed: 11/07/2023] Open
Abstract
Phenotype switching from a wild type (WT) to a slow-growing subpopulation, referred to as small colony variants (SCVs), supports an infectious lifestyle of Staphylococcus epidermidis, the leading cause of medical device-related infections. Specific mechanisms underlying formation of SCVs and involved in the shaping of their pathogenic potential are of particular interest for stable strains as they have been only rarely cultured from clinical specimens. As the SCV phenotype stability implies the existence of genetic changes, the whole genome sequence of a stable, hemin-dependent S. epidermidis SCV strain (named 49SCV) involved in a late prosthetic joint infection was analyzed. The strain was isolated in a monoculture without a corresponding WT clone, therefore, its genome was compared against five reference S. epidermidis strains (ATCC12228, ATCC14990, NBRC113846, O47, and RP62A), both at the level of the genome structure and coding sequences. According to the Multilocus Sequence Typing analysis, the 49SCV strain represented the sequence type 2 (ST2) regarded as the most prominent infection-causing lineage with a worldwide dissemination. Genomic features unique to 49SCV included the absence of the Staphylococcal Cassette Chromosome (SCC), ~12 kb deletion with the loss of genes involved in the arginine deiminase pathway, and frameshift-generating mutations within the poly(A) and poly(T) homopolymeric tracts. Indels were identified in loci associated with adherence, metabolism, stress response, virulence, and cell wall synthesis. Of note, deletion in the poly(A) of the hemA gene has been considered a possible trigger factor for the phenotype transition and hemin auxotrophy in the strain. To our knowledge, the study represents the first genomic characterization of a clinical, stable and hemin-dependent S. epidermidis SCV strain. We propose that previously unreported indels in the homopolymeric tracts can constitute a background of the SCV phenotype due to a resulting truncation of the corresponding proteins and their possible biological dysfunction. Streamline of genetic content evidenced by the loss of the SCC and a large genomic deletion can represent a possible strategy associated both with the SCV phenotype and its adaptation to chronicity.
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Affiliation(s)
- Agnieszka Bogut
- Chair and Department of Medical Microbiology, Medical University of Lublin, Lublin, Poland
| | - Piotr Koper
- Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Małgorzata Marczak
- Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Paulina Całka
- Chair and Department of Forensic Medicine, Medical University of Lublin, Lublin, Poland
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2
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Sutton JAF, Cooke M, Tinajero-Trejo M, Wacnik K, Salamaga B, Portman-Ross C, Lund VA, Hobbs JK, Foster SJ. The roles of GpsB and DivIVA in Staphylococcus aureus growth and division. Front Microbiol 2023; 14:1241249. [PMID: 37711690 PMCID: PMC10498921 DOI: 10.3389/fmicb.2023.1241249] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 08/04/2023] [Indexed: 09/16/2023] Open
Abstract
The spheroid bacterium Staphylococcus aureus is often used as a model of morphogenesis due to its apparently simple cell cycle. S. aureus has many cell division proteins that are conserved across bacteria alluding to common functions. However, despite intensive study, we still do not know the roles of many of these components. Here, we have examined the functions of the paralogues DivIVA and GpsB in the S. aureus cell cycle. Cells lacking gpsB display a more spherical phenotype than the wild-type cells, which is associated with a decrease in peripheral cell wall peptidoglycan synthesis. This correlates with increased localization of penicillin-binding proteins at the developing septum, notably PBPs 2 and 3. Our results highlight the role of GpsB as an apparent regulator of cell morphogenesis in S. aureus.
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Affiliation(s)
- Joshua A. F. Sutton
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Mark Cooke
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Mariana Tinajero-Trejo
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Katarzyna Wacnik
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Bartłomiej Salamaga
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Callum Portman-Ross
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Victoria A. Lund
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
| | - Jamie K. Hobbs
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Simon J. Foster
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
- The Florey Institute for Host-Pathogen Interactions, University of Sheffield, Sheffield, United Kingdom
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3
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The Staphylococcus aureus cell division protein, DivIC, interacts with the cell wall and controls its biosynthesis. Commun Biol 2022; 5:1228. [DOI: 10.1038/s42003-022-04161-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 10/24/2022] [Indexed: 11/13/2022] Open
Abstract
AbstractBacterial cell division is a complex, dynamic process that requires multiple protein components to orchestrate its progression. Many division proteins are highly conserved across bacterial species alluding to a common, basic mechanism. Central to division is a transmembrane trimeric complex involving DivIB, DivIC and FtsL in Gram-positives. Here, we show a distinct, essential role for DivIC in division and survival of Staphylococcus aureus. DivIC spatially regulates peptidoglycan synthesis, and consequently cell wall architecture, by influencing the recruitment to the division septum of the major peptidoglycan synthetases PBP2 and FtsW. Both the function of DivIC and its recruitment to the division site depend on its extracellular domain, which interacts with the cell wall via binding to wall teichoic acids. DivIC facilitates the spatial and temporal coordination of peptidoglycan synthesis with the developing architecture of the septum during cell division. A better understanding of the cell division mechanisms in S. aureus and other pathogenic microorganisms can provide possibilities for the development of new, more effective treatments for bacterial infections.
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Hammond LR, Sacco MD, Khan SJ, Spanoudis C, Hough-Neidig A, Chen Y, Eswara PJ. GpsB Coordinates Cell Division and Cell Surface Decoration by Wall Teichoic Acids in Staphylococcus aureus. Microbiol Spectr 2022; 10:e0141322. [PMID: 35647874 PMCID: PMC9241681 DOI: 10.1128/spectrum.01413-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
Bacterial cell division is a complex and highly regulated process requiring the coordination of many different proteins. Despite substantial work in model organisms, our understanding of the systems regulating cell division in noncanonical organisms, including critical human pathogens, is far from complete. One such organism is Staphylococcus aureus, a spherical bacterium that lacks known cell division regulatory proteins. Recent studies on GpsB, a protein conserved within the Firmicutes phylum, have provided insight into cell division regulation in S. aureus and other related organisms. It has been revealed that GpsB coordinates cell division and cell wall synthesis in multiple species. In S. aureus, we have previously shown that GpsB directly regulates FtsZ polymerization. In this study, using Bacillus subtilis as a tool, we isolated spontaneous suppressors that abrogate the lethality of S. aureus GpsB overproduction in B. subtilis. Through characterization, we identified several residues important for the function of GpsB. Furthermore, we discovered an additional role for GpsB in wall teichoic acid (WTA) biosynthesis in S. aureus. Specifically, we show that GpsB directly interacts with the WTA export protein TarG. We also identified a region in GpsB that is crucial for this interaction. Analysis of TarG localization in S. aureus suggests that WTA machinery is part of the divisome complex. Taken together, this research illustrates how GpsB performs an essential function in S. aureus by directly linking the tightly regulated cell cycle processes of cell division and WTA-mediated cell surface decoration. IMPORTANCE Cytokinesis in bacteria involves an intricate orchestration of several key cell division proteins and other factors involved in building a robust cell envelope. Presence of teichoic acids is a signature characteristic of the Gram-positive cell wall. By characterizing the role of Staphylococcus aureus GpsB, an essential cell division protein in this organism, we have uncovered an additional role for GpsB in wall teichoic acid (WTA) biosynthesis. We show that GpsB directly interacts with TarG of the WTA export complex. We also show that this function of GpsB may be conserved in other GpsB homologs as GpsB and the WTA exporter complex follow similar localization patterns. It has been suggested that WTA acts as a molecular signal to control the activity of autolytic enzymes, especially during the separation of conjoined daughter cells. Thus, our results reveal that GpsB, in addition to playing a role in cell division, may also help coordinate WTA biogenesis.
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Affiliation(s)
- Lauren R. Hammond
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Michael D. Sacco
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Sebastian J. Khan
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Catherine Spanoudis
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Abigail Hough-Neidig
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
| | - Yu Chen
- Department of Molecular Medicine, University of South Florida, Tampa, Florida, USA
| | - Prahathees J. Eswara
- Department of Cell Biology, Microbiology, and Molecular Biology, University of South Florida, Tampa, Florida, USA
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Rajaei A, Rowe HM, Neely MN. The LCP Family Protein, Psr, Is Required for Cell Wall Integrity and Virulence in Streptococcus agalactiae. Microorganisms 2022; 10:microorganisms10020217. [PMID: 35208672 PMCID: PMC8875755 DOI: 10.3390/microorganisms10020217] [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: 12/15/2021] [Revised: 01/14/2022] [Accepted: 01/15/2022] [Indexed: 02/04/2023] Open
Abstract
A robust cell envelope is the first line of protection for an infecting pathogen when encountering the immune defense of its host. In Gram-positive organisms, LytR-CpsA-Psr (LCP) family proteins play a major role in the synthesis and assembly of the cell envelope. While these proteins could be considered for potential new drug targets, not enough is known about how they function to support the integrity of the cell wall. Streptococcus agalactiae (group B streptococcus or GBS) is known to encode at least three LCP family proteins, including CpsA, LytR (BrpA) and Psr. Using strains of GBS that have mutations in two of the three LCP proteins, we were able to determine a role for these proteins in GBS cell wall integrity. The results presented here demonstrate that the absence of Psr results in a decreased growth rate, decreased viability over time, inconsistent cocci morphology and diminished cell wall integrity, as well as an increased penicillin susceptibility, decreased capsule levels and attenuation in virulence in a zebrafish model of infectious disease. A strain that is missing two of the LCP family proteins, CpsA and Psr, exhibits an increase in these defective phenotypes, indicating that CpsA and Psr are partially redundant in function.
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Affiliation(s)
- Atefeh Rajaei
- Molecular and Biomedical Sciences Department, University of Maine, Orono, ME 04469, USA;
| | - Hannah M. Rowe
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA;
| | - Melody N. Neely
- Molecular and Biomedical Sciences Department, University of Maine, Orono, ME 04469, USA;
- Correspondence:
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6
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Pan T, Guan J, Li Y, Sun B. LcpB Is a Pyrophosphatase Responsible for Wall Teichoic Acid Synthesis and Virulence in Staphylococcus aureus Clinical Isolate ST59. Front Microbiol 2021; 12:788500. [PMID: 34975809 PMCID: PMC8716876 DOI: 10.3389/fmicb.2021.788500] [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] [Received: 10/02/2021] [Accepted: 11/30/2021] [Indexed: 11/17/2022] Open
Abstract
The community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) causes severe pandemics primarily consisting of skin and soft tissue infections. However, the underlying pathomechanisms of the bacterium are yet to fully understood. The present study identifies LcpB protein, which belongs to the LytR-A-Psr (LCP) family, is crucial for cell wall synthesis and virulence in S. aureus. The findings revealed that LcpB is a pyrophosphatase responsible for wall teichoic acid synthesis. The results also showed that LcpB regulates enzyme activity through specific key arginine sites in its LCP domain. Furthermore, knockout of lcpB in the CA-MRSA isolate ST59 resulted in enhanced hemolytic activity, enlarged of abscesses, and increased leukocyte infiltration. Meanwhile, we also found that LcpB regulates virulence in agr-independent manner and the key sites for pyrophosphatase of LcpB play critical roles in regulating the virulence. In addition, the results showed that the role of LcpB was different between methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA). This study therefore highlights the dual role of LcpB in cell wall synthesis and regulation of virulence. These insights on the underlying molecular mechanisms can thus guide the development of novel anti-infective strategies.
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Affiliation(s)
- Ting Pan
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Jing Guan
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yujie Li
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Baolin Sun
- Department of Oncology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
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7
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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: 52] [Impact Index Per Article: 17.3] [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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8
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LytR-CpsA-Psr Glycopolymer Transferases: Essential Bricks in Gram-Positive Bacterial Cell Wall Assembly. Int J Mol Sci 2021; 22:ijms22020908. [PMID: 33477538 PMCID: PMC7831098 DOI: 10.3390/ijms22020908] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/28/2022] Open
Abstract
The cell walls of Gram-positive bacteria contain a variety of glycopolymers (CWGPs), a significant proportion of which are covalently linked to the peptidoglycan (PGN) scaffolding structure. Prominent CWGPs include wall teichoic acids of Staphylococcus aureus, streptococcal capsules, mycobacterial arabinogalactan, and rhamnose-containing polysaccharides of lactic acid bacteria. CWGPs serve important roles in bacterial cellular functions, morphology, and virulence. Despite evident differences in composition, structure and underlaying biosynthesis pathways, the final ligation step of CWGPs to the PGN backbone involves a conserved class of enzymes-the LytR-CpsA-Psr (LCP) transferases. Typically, the enzymes are present in multiple copies displaying partly functional redundancy and/or preference for a distinct CWGP type. LCP enzymes require a lipid-phosphate-linked glycan precursor substrate and catalyse, with a certain degree of promiscuity, CWGP transfer to PGN of different maturation stages, according to in vitro evidence. The prototype attachment mode is that to the C6-OH of N-acetylmuramic acid residues via installation of a phosphodiester bond. In some cases, attachment proceeds to N-acetylglucosamine residues of PGN-in the case of the Streptococcus agalactiae capsule, even without involvement of a phosphate bond. A novel aspect of LCP enzymes concerns a predicted role in protein glycosylation in Actinomyces oris. Available crystal structures provide further insight into the catalytic mechanism of this biologically important class of enzymes, which are gaining attention as new targets for antibacterial drug discovery to counteract the emergence of multidrug resistant bacteria.
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9
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Li FKK, Rosell FI, Gale RT, Simorre JP, Brown ED, Strynadka NCJ. Crystallographic analysis of Staphylococcus aureus LcpA, the primary wall teichoic acid ligase. J Biol Chem 2020; 295:2629-2639. [PMID: 31969390 PMCID: PMC7049971 DOI: 10.1074/jbc.ra119.011469] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 01/20/2020] [Indexed: 12/12/2022] Open
Abstract
Gram-positive bacteria, including major clinical pathogens such as Staphylococcus aureus, are becoming increasingly drug-resistant. Their cell walls are composed of a thick layer of peptidoglycan (PG) modified by the attachment of wall teichoic acid (WTA), an anionic glycopolymer that is linked to pathogenicity and regulation of cell division and PG synthesis. The transfer of WTA from lipid carriers to PG, catalyzed by the LytR-CpsA-Psr (LCP) enzyme family, offers a unique extracellular target for the development of new anti-infective agents. Inhibitors of LCP enzymes have the potential to manage a wide range of bacterial infections because the target enzymes are implicated in the assembly of many other bacterial cell wall polymers, including capsular polysaccharide of streptococcal species and arabinogalactan of mycobacterial species. In this study, we present the first crystal structure of S. aureus LcpA with bound substrate at 1.9 Å resolution and those of Bacillus subtilis LCP enzymes, TagT, TagU, and TagV, in the apo form at 1.6-2.8 Å resolution. The structures of these WTA transferases provide new insight into the binding of lipid-linked WTA and enable assignment of the catalytic roles of conserved active-site residues. Furthermore, we identified potential subsites for binding the saccharide core of PG using computational docking experiments, and multiangle light-scattering experiments disclosed novel oligomeric states of the LCP enzymes. The crystal structures and modeled substrate-bound complexes of the LCP enzymes reported here provide insights into key features linked to substrate binding and catalysis and may aid the structure-guided design of specific LCP inhibitors.
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Affiliation(s)
- Franco K K Li
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Federico I Rosell
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Robert T Gale
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Jean-Pierre Simorre
- Université Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 38000 Grenoble, France
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Centre for Blood Research, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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10
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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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11
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Patras KA, Derieux J, Al-Bassam MM, Adiletta N, Vrbanac A, Lapek JD, Zengler K, Gonzalez DJ, Nizet V. Group B Streptococcus Biofilm Regulatory Protein A Contributes to Bacterial Physiology and Innate Immune Resistance. J Infect Dis 2019; 218:1641-1652. [PMID: 29868829 DOI: 10.1093/infdis/jiy341] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/02/2018] [Indexed: 12/18/2022] Open
Abstract
Background Streptococcus agalactiae (group B Streptococcus [GBS]) asymptomatically colonizes approximately 20% of adults; however, GBS causes severe disease in susceptible populations, including newborns, pregnant women, and elderly individuals. In shifting between commensal and pathogenic states, GBS reveals multiple mechanisms of virulence factor control. Here we describe a GBS protein that we named "biofilm regulatory protein A" (BrpA) on the basis of its homology with BrpA from Streptococcus mutans. Methods We coupled phenotypic assays, RNA sequencing, human neutrophil and whole-blood killing assays, and murine infection models to investigate the contribution of BrpA to GBS physiology and virulence. Results Sequence analysis identified BrpA as a LytR-CpsA-Psr enzyme. Targeted mutagenesis yielded a GBS mutant (ΔbrpA) with normal ultrastructural morphology but a 6-fold increase in chain length, a biofilm defect, and decreased acid tolerance. GBS ΔbrpA stimulated increased neutrophil reactive oxygen species and proved more susceptible to human and murine blood and neutrophil killing. Notably, the wild-type parent outcompeted ΔbrpA GBS in murine sepsis and vaginal colonization models. RNA sequencing of ΔbrpA uncovered multiple differences from the wild-type parent, including pathways of cell wall synthesis and cellular metabolism. Conclusions We propose that BrpA is an important virulence regulator and potential target for design of novel antibacterial therapeutics against GBS.
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Affiliation(s)
- Kathryn A Patras
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla
| | - Jaclyn Derieux
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla
| | - Mahmoud M Al-Bassam
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla
| | - Nichole Adiletta
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla
| | - Alison Vrbanac
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla
| | - John D Lapek
- Department of Pharmacology, School of Medicine, University of California-San Diego, La Jolla.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla
| | - Karsten Zengler
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla
| | - David J Gonzalez
- Department of Pharmacology, School of Medicine, University of California-San Diego, La Jolla.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California-San Diego, La Jolla.,Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California-San Diego, La Jolla
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12
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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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13
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Tran NT, Huang X, Hong HJ, Bush MJ, Chandra G, Pinto D, Bibb MJ, Hutchings MI, Mascher T, Buttner MJ. Defining the regulon of genes controlled by σ E , a key regulator of the cell envelope stress response in Streptomyces coelicolor. Mol Microbiol 2019; 112:461-481. [PMID: 30907454 PMCID: PMC6767563 DOI: 10.1111/mmi.14250] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2019] [Indexed: 01/01/2023]
Abstract
The extracytoplasmic function (ECF) σ factor, σE , is a key regulator of the cell envelope stress response in Streptomyces coelicolor. Although its role in maintaining cell wall integrity has been known for over a decade, a comprehensive analysis of the genes under its control has not been undertaken. Here, using a combination of chromatin immunoprecipitation-sequencing (ChIP-seq), microarray transcriptional profiling and bioinformatic analysis, we attempt to define the σE regulon. Approximately half of the genes identified encode proteins implicated in cell envelope function. Seventeen novel targets were validated by S1 nuclease mapping or in vitro transcription, establishing a σE -binding consensus. Subsequently, we used bioinformatic analysis to look for conservation of the σE target promoters identified in S. coelicolor across 19 Streptomyces species. Key proteins under σE control across the genus include the actin homolog MreB, three penicillin-binding proteins, two L,D-transpeptidases, a LytR-CpsA-Psr-family protein predicted to be involved in cell wall teichoic acid deposition and a predicted MprF protein, which adds lysyl groups to phosphatidylglycerol to neutralize membrane surface charge. Taken together, these analyses provide biological insight into the σE -mediated cell envelope stress response in the genus Streptomyces.
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Affiliation(s)
- Ngat T Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Xiaoluo Huang
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.,Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, Planegg-Martinsried, 82152, Germany
| | - Hee-Jeon Hong
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Matthew J Bush
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Govind Chandra
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Daniela Pinto
- Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, Planegg-Martinsried, 82152, Germany
| | - Maureen J Bibb
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Matthew I Hutchings
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Thorsten Mascher
- Department Biology I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, Planegg-Martinsried, 82152, Germany
| | - Mark J Buttner
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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14
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Wen ZT, Scott-Anne K, Liao S, De A, Luo M, Kovacs C, Narvaez BS, Faustoferri R, Yu Q, Taylor CM, Quivey RG. Deficiency of BrpA in Streptococcus mutans reduces virulence in rat caries model. Mol Oral Microbiol 2018; 33:353-363. [PMID: 29888871 PMCID: PMC6158100 DOI: 10.1111/omi.12230] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2018] [Indexed: 01/09/2023]
Abstract
Our recent studies have shown that BrpA in Streptococcus mutans plays a critical role in cell envelope biogenesis, stress responses, and biofilm formation. In this study, a 10-species consortium was used to assess how BrpA deficiency influences the establishment, persistence, and competitiveness of S. mutans during growth in a community under conditions typical of the oral cavity. Results showed that, like the wild-type, the brpA mutant was able to colonize and establish on the surfaces tested. Relative to the wild-type, however, the brpA mutant had a reduced ability to persist and grow in the 10-species consortium (P < .001). A rat caries model was also used to examine the effect of BrpA, as well as Psr, a BrpA paralog, on S. mutans cariogenicity. The results showed no major differences in infectivity between the wild-type and the brpA and psr mutants. Unlike the wild-type, however, infection with the brpA mutant, but not the psr mutant, showed no significant differences in both total numbers of carious lesions and caries severity, compared with the control group that received bacterial growth medium (P > .05). Metagenomic and quantitative polymerase chain reaction analysis showed that S. mutans infection caused major alterations in the composition of the rats' plaque microbiota and that significantly less S. mutans was identified in the rats infected with the brpA mutant compared with those infected with the wild-type and the psr mutant. These results further suggest that BrpA plays a critical role in S. mutans pathophysiology and that BrpA has potential as a therapeutic target in the modulation of S. mutans virulence.
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Affiliation(s)
- Zezhang T. Wen
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
- Center of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Kathy Scott-Anne
- Center of Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Sumei Liao
- Center of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Arpan De
- Department of Comprehensive Dentistry and Biomaterials, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Meng Luo
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Christopher Kovacs
- Center of Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | | | - Roberta Faustoferri
- Center of Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY
| | - Qingzhao Yu
- Department of Biostatistics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Christopher M. Taylor
- Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Robert G. Quivey
- Center of Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY
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15
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Luciferase Reporter Gene System to Detect Cell Wall Stress Stimulon Induction in Staphylococcus aureus. Methods Mol Biol 2018; 1440:139-50. [PMID: 27311670 DOI: 10.1007/978-1-4939-3676-2_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Luciferase reporter gene fusions provide an extremely rapid and sensitive tool for measuring the induction or repression of stress responses in bacteria. Staphylococcus aureus activates the expression of a cell wall stress stimulon (CWSS) in response to the inhibition or disruption of cell wall synthesis. The highly sensitive promoter-reporter gene fusion construct psas016 p-luc+ can be used to quantify and compare any changes in CWSS expression levels and induction kinetics. Potential uses of this system include identifying and characterizing novel cell wall-targeting antibacterial agents, identifying genomic loci influencing cell envelope synthesis and detecting changes in CWSS expression that could be linked to decreased antibiotic susceptibility profiles in clinical isolates.
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16
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Gale RT, Li FKK, Sun T, Strynadka NCJ, Brown ED. B. subtilis LytR-CpsA-Psr Enzymes Transfer Wall Teichoic Acids from Authentic Lipid-Linked Substrates to Mature Peptidoglycan In Vitro. Cell Chem Biol 2017; 24:1537-1546.e4. [PMID: 29107701 DOI: 10.1016/j.chembiol.2017.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 08/01/2017] [Accepted: 09/18/2017] [Indexed: 12/11/2022]
Abstract
Gram-positive bacteria endow their peptidoglycan with glycopolymers that are crucial for viability and pathogenesis. However, the cellular machinery that executes this function is not well understood. While decades of genetic and phenotypic work have highlighted the LytR-CpsA-Psr (LCP) family of enzymes as cell-wall glycopolymer transferases, their in vitro characterization has been elusive, largely due to a paucity of tools for functional assays. In this report, we synthesized authentic undecaprenyl diphosphate-linked wall teichoic acid (WTA) intermediates and built an assay system capable of monitoring LCP-mediated glycopolymer transfer. We report that all Bacillus subtilis LCP enzymes anchor WTAs to peptidoglycan in vitro. Furthermore, we probed the catalytic requirements and substrate preferences for these LCP enzymes and elaborated in vitro conditions for facile tests of enzyme function. This work sheds light on the molecular features of glycopolymer transfer and aims to aid drug discovery and development programs exploiting this promising antibacterial target.
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Affiliation(s)
- Robert T Gale
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Franco K K Li
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Tianjun Sun
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ON L8N 3Z5, Canada.
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17
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Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans. Appl Environ Microbiol 2017; 83:AEM.00928-17. [PMID: 28687645 DOI: 10.1128/aem.00928-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/29/2017] [Indexed: 12/20/2022] Open
Abstract
Streptococcus mutans is known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen. S. mutans strains deficient in rgpG, encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. The rgpG deficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, the rgpG mutant existed primarily in chains of swollen, "squarish" dividing cells. Deficiency of rgpG also causes significant reduction in biofilm formation (P < 0.01). Double and triple mutants with deficiency in brpA and/or psr, genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using the rgpG mutant. There were no major differences in growth rates between the wild-type strain and the rgpG brpA and rgpG psr double mutants, but the growth rate of the rgpG brpA psr triple mutant was reduced drastically (P < 0.001). Under transmission electron microscopy, both double mutants resembled the rgpG mutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, the rgpG mutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and the brpA and psr single mutants. These results suggest that RgpG in S. mutans plays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope.IMPORTANCEStreptococcus mutans, a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation by S. mutans, indicative of a significant role of RGP in cell division and biofilm formation in S. mutans These results are novel not only in S. mutans, but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr in S. mutans are involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation in S. mutans This study reveals new potential targets to develop anticaries therapeutics.
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18
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Modulatory Effects of a Subinhibitory Concentration of Clindamycin in Community-Acquired Methicillin-Resistant Staphylococcus aureus Strains of Sequence Type 30. Antimicrob Agents Chemother 2017; 61:61/3/e02254-16. [PMID: 28232310 DOI: 10.1128/aac.02254-16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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19
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Schaefer K, Matano LM, Qiao Y, Kahne D, Walker S. In vitro reconstitution demonstrates the cell wall ligase activity of LCP proteins. Nat Chem Biol 2017; 13:396-401. [PMID: 28166208 DOI: 10.1038/nchembio.2302] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 12/01/2016] [Indexed: 02/02/2023]
Abstract
Sacculus is a peptidoglycan (PG) matrix that protects bacteria from osmotic lysis. In Gram-positive organisms, the sacculus is densely functionalized with glycopolymers important for survival, but the way in which assembly occurs is not known. In Staphylococcus aureus, three LCP (LytR-CpsA-Psr) family members have been implicated in attaching the major glycopolymer wall teichoic acid (WTA) to PG, but ligase activity has not been demonstrated for these or any other LCP proteins. Using WTA and PG substrates produced chemoenzymatically, we show that all three proteins can transfer WTA precursors to nascent PGs, establishing that LCP proteins are PG-glycopolymer ligases. Although all S. aureus LCP proteins have the capacity to attach WTA to PG, we show that their cellular functions are not redundant. Strains lacking lcpA have phenotypes similar to those of WTA-null strains, indicating that this is the most important WTA ligase. This work provides a foundation for studying how LCP enzymes participate in cell wall assembly.
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Affiliation(s)
- Kaitlin Schaefer
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA.,Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts, USA
| | - Leigh M Matano
- Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts, USA
| | - Yuan Qiao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA.,Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts, USA
| | - Daniel Kahne
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Suzanne Walker
- Department of Microbiology and Immunology, Harvard Medical School, Boston, Massachusetts, USA
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20
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Santos-Beneit F, Ordóñez-Robles M, Martín JF. Glycopeptide resistance: Links with inorganic phosphate metabolism and cell envelope stress. Biochem Pharmacol 2016; 133:74-85. [PMID: 27894856 DOI: 10.1016/j.bcp.2016.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/15/2016] [Indexed: 10/20/2022]
Abstract
Antimicrobial resistance is a critical health issue today. Many pathogens have become resistant to many or all available antibiotics and limited new antibiotics are in the pipeline. Glycopeptides are used as a 'last resort' antibiotic treatment for many bacterial infections, but worryingly, glycopeptide resistance has spread to very important pathogens such as Enterococcus faecium and Staphylococcus aureus. Bacteria confront multiple stresses in their natural environments, including nutritional starvation and the action of cell-wall stressing agents. These stresses impact bacterial susceptibility to different antimicrobials. This article aims to review the links between glycopeptide resistance and different stresses, especially those related with cell-wall biosynthesis and inorganic phosphate metabolism, and to discuss promising alternatives to classical antibiotics to avoid the problem of antimicrobial resistance.
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Affiliation(s)
- Fernando Santos-Beneit
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Medical School, Newcastle University, NE2 4AX Newcastle upon Tyne, UK
| | - María Ordóñez-Robles
- Department of Biotechnology, Faculty of Natural Sciences and Technology, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Juan F Martín
- Microbiology Area, Department of Molecular Biology, University of León, 24071 León, Spain.
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21
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Maréchal M, Amoroso A, Morlot C, Vernet T, Coyette J, Joris B. Enterococcus hirae LcpA (Psr), a new peptidoglycan-binding protein localized at the division site. BMC Microbiol 2016; 16:239. [PMID: 27729019 PMCID: PMC5059904 DOI: 10.1186/s12866-016-0844-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 09/21/2016] [Indexed: 12/26/2022] Open
Abstract
Background Proteins from the LytR-CpsA-Psr family are found in almost all Gram-positive bacteria. Although LCP proteins have been studied in other pathogens, their functions in enterococci remain uncharacterized. The Psr protein from Enterococcus hirae, here renamed LcpA, previously associated with the regulation of the expression of the low-affinity PBP5 and β-lactam resistance, has been characterized. Results LcpA protein of E. hirae ATCC 9790 has been produced and purified with and without its transmembrane helix. LcpA appears, through different methods, to be localized in the membrane, in agreement with in silico predictions. The interaction of LcpA with E. hirae cell wall indicates that LcpA binds enterococcal peptidoglycan, regardless of the presence of secondary cell wall polymers. Immunolocalization experiments showed that LcpA and PBP5 are localized at the division site of E. hirae. Conclusions LcpA belongs to the LytR-CpsA-Psr family. Its topology, localization and binding to peptidoglycan support, together with previous observations on defective mutants, that LcpA plays a role related to the cell wall metabolism, probably acting as a phosphotransferase catalyzing the attachment of cell wall polymers to the peptidoglycan. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0844-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maxime Maréchal
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium
| | - Ana Amoroso
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium
| | - Cécile Morlot
- University Grenoble Alpes, IBS, Grenoble, F-38044, France.,CNRS, IBS, Grenoble, F-38044, France.,CEA, IBS, Grenoble, F-38044, France
| | - Thierry Vernet
- University Grenoble Alpes, IBS, Grenoble, F-38044, France.,CNRS, IBS, Grenoble, F-38044, France.,CEA, IBS, Grenoble, F-38044, France
| | - Jacques Coyette
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium
| | - Bernard Joris
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium.
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22
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Complete Reconstitution of the Vancomycin-Intermediate Staphylococcus aureus Phenotype of Strain Mu50 in Vancomycin-Susceptible S. aureus. Antimicrob Agents Chemother 2016; 60:3730-42. [PMID: 27067329 PMCID: PMC4879404 DOI: 10.1128/aac.00420-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/01/2016] [Indexed: 12/23/2022] Open
Abstract
Complete reconstitution of the vancomycin-intermediate Staphylococcus aureus (VISA) phenotype of strain Mu50 was achieved by sequentially introducing mutations into six genes of vancomycin-susceptible S. aureus (VSSA) strain N315ΔIP. The six mutated genes were detected in VISA strain Mu50 but not in N315ΔIP. Introduction of the mutation Ser329Leu into vraS, encoding the sensor histidine kinase of the vraSR two-component regulatory (TCR) system, and another mutation, Glu146Lys, into msrR, belonging to the LytR-CpsA-Psr (LCP) family, increased the level of vancomycin resistance to that detected in heterogeneous vancomycin-intermediate S. aureus (hVISA) strain Mu3. Introduction of two more mutations, Asn197Ser into graR of the graSR TCR system and His481Tyr into rpoB, encoding the β subunit of RNA polymerase, converted the hVISA strain into a VISA strain with the same level of vancomycin resistance as Mu50. Surprisingly, however, the constructed quadruple mutant strain ΔIP4 did not have a thickened cell wall, a cardinal feature of the VISA phenotype. Subsequent study showed that cell wall thickening was an inducible phenotype in the mutant strain, whereas it was a constitutive one in Mu50. Finally, introduction of the Ala297Val mutation into fdh2, which encodes a putative formate dehydrogenase, or a 67-amino-acid sequence deletion into sle1 [sle1(Δ67aa)], encoding the hydrolase of N-acetylmuramyl-l-alanine amidase in the peptidoglycan, converted inducible cell wall thickening into constitutive cell wall thickening. sle1(Δ67aa) was found to cause a drastic decrease in autolysis activity. Thus, all six mutated genes required for acquisition of the VISA phenotype were directly or indirectly involved in the regulation of cell physiology. The VISA phenotype seemed to be achieved through multiple genetic events accompanying drastic changes in cell physiology.
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23
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Mann PA, Müller A, Wolff KA, Fischmann T, Wang H, Reed P, Hou Y, Li W, Müller CE, Xiao J, Murgolo N, Sher X, Mayhood T, Sheth PR, Mirza A, Labroli M, Xiao L, McCoy M, Gill CJ, Pinho MG, Schneider T, Roemer T. Chemical Genetic Analysis and Functional Characterization of Staphylococcal Wall Teichoic Acid 2-Epimerases Reveals Unconventional Antibiotic Drug Targets. PLoS Pathog 2016; 12:e1005585. [PMID: 27144276 PMCID: PMC4856313 DOI: 10.1371/journal.ppat.1005585] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 03/29/2016] [Indexed: 11/18/2022] Open
Abstract
Here we describe a chemical biology strategy performed in Staphylococcus aureus and Staphylococcus epidermidis to identify MnaA, a 2-epimerase that we demonstrate interconverts UDP-GlcNAc and UDP-ManNAc to modulate substrate levels of TarO and TarA wall teichoic acid (WTA) biosynthesis enzymes. Genetic inactivation of mnaA results in complete loss of WTA and dramatic in vitro β-lactam hypersensitivity in methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE). Likewise, the β-lactam antibiotic imipenem exhibits restored bactericidal activity against mnaA mutants in vitro and concomitant efficacy against 2-epimerase defective strains in a mouse thigh model of MRSA and MRSE infection. Interestingly, whereas MnaA serves as the sole 2-epimerase required for WTA biosynthesis in S. epidermidis, MnaA and Cap5P provide compensatory WTA functional roles in S. aureus. We also demonstrate that MnaA and other enzymes of WTA biosynthesis are required for biofilm formation in MRSA and MRSE. We further determine the 1.9Å crystal structure of S. aureus MnaA and identify critical residues for enzymatic dimerization, stability, and substrate binding. Finally, the natural product antibiotic tunicamycin is shown to physically bind MnaA and Cap5P and inhibit 2-epimerase activity, demonstrating that it inhibits a previously unanticipated step in WTA biosynthesis. In summary, MnaA serves as a new Staphylococcal antibiotic target with cognate inhibitors predicted to possess dual therapeutic benefit: as combination agents to restore β-lactam efficacy against MRSA and MRSE and as non-bioactive prophylactic agents to prevent Staphylococcal biofilm formation. Staphylococcus aureus and Staphylococcus epidermidis cause life-threatening infections that are commonly acquired in hospitals as well as the community and remain difficult to treat with current antibiotics. In part, this is due to the emergence of methicillin-resistant S. aureus and S. epidermidis (MRSA and MRSE), which exhibit broad resistance to β-lactams such as penicillin and other members of this important founding class of antibiotics. Compounding this problem, Staphylococci commonly colonize the surface of catheters and other medical devices, forming bacterial communities that are intrinsically resistant to antibiotics. Here we functionally characterize a family of 2-epimerases, named MnaA and Cap5P, that we demonstrate by genetic, biochemical, and X-ray crystallography means are essential for wall teichoic acid biosynthesis and that upon their genetic inactivation render methicillin-resistant Staphylococci unable to form biofilms as well as broadly hypersusceptible to β-lactam antibiotics both in vitro and in a host infection setting. WTA 2-epimerases therefore constitute a novel class of methicillin-resistant Staphylococcal drug targets.
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Affiliation(s)
- Paul A. Mann
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Anna Müller
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Kerstin A. Wolff
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Thierry Fischmann
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Hao Wang
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Patricia Reed
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Yan Hou
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Wenjin Li
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry, University of Bonn, Bonn, Germany
| | - Christa E. Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry, University of Bonn, Bonn, Germany
| | - Jianying Xiao
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Nicholas Murgolo
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Xinwei Sher
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Todd Mayhood
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Payal R. Sheth
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Asra Mirza
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Marc Labroli
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Li Xiao
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Mark McCoy
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Charles J. Gill
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Tanja Schneider
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Terry Roemer
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
- * E-mail:
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Chan YGY, Frankel MB, Missiakas D, Schneewind O. SagB Glucosaminidase Is a Determinant of Staphylococcus aureus Glycan Chain Length, Antibiotic Susceptibility, and Protein Secretion. J Bacteriol 2016; 198:1123-36. [PMID: 26811319 PMCID: PMC4800868 DOI: 10.1128/jb.00983-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/20/2016] [Indexed: 01/18/2023] Open
Abstract
UNLABELLED The envelope of Staphylococcus aureus is comprised of peptidoglycan and its attached secondary polymers, teichoic acid, capsular polysaccharide, and protein. Peptidoglycan synthesis involves polymerization of lipid II precursors into glycan strands that are cross-linked at wall peptides. It is not clear whether peptidoglycan structure is principally determined during polymerization or whether processive enzymes affect cell wall structure and function, for example, by generating conduits for protein secretion. We show here that S. aureus lacking SagB, a membrane-associated N-acetylglucosaminidase, displays growth and cell-morphological defects caused by the exaggerated length of peptidoglycan strands. SagB cleaves polymerized glycan strands to their physiological length and modulates antibiotic resistance in methicillin-resistant S. aureus (MRSA). Deletion of sagB perturbs protein trafficking into and across the envelope, conferring defects in cell wall anchoring and secretion, as well as aberrant excretion of cytoplasmic proteins. IMPORTANCE Staphylococcus aureus is thought to secrete proteins across the plasma membrane via the Sec pathway; however, protein transport across the cell wall envelope has heretofore not been studied. We report that S. aureus sagB mutants generate elongated peptidoglycan strands and display defects in protein secretion as well as aberrant excretion of cytoplasmic proteins. These results suggest that the thick peptidoglycan layer of staphylococci presents a barrier for protein secretion and that SagB appears to extend the Sec pathway across the cell wall envelope.
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Affiliation(s)
- Yvonne G Y Chan
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Matthew B Frankel
- 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, Argonne, Illinois, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
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Colagiorgi A, Turroni F, Mancabelli L, Serafini F, Secchi A, van Sinderen D, Ventura M. Insights into teichoic acid biosynthesis byBifidobacterium bifidumPRL2010. FEMS Microbiol Lett 2015; 362:fnv141. [DOI: 10.1093/femsle/fnv141] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2015] [Indexed: 12/23/2022] Open
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CpsA, a LytR-CpsA-Psr Family Protein in Mycobacterium marinum, Is Required for Cell Wall Integrity and Virulence. Infect Immun 2015; 83:2844-54. [PMID: 25939506 DOI: 10.1128/iai.03081-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/20/2015] [Indexed: 12/28/2022] Open
Abstract
LytR-CpsA-Psr family proteins play an important role in bacterial cell wall integrity. Although the pathogenic relevance of LytR-CpsA-Psr family proteins has been studied in a few bacterial pathogens, their function in mycobacteria remains uncharacterized. In this work, a transposon insertion mutant (cpsA::Tn) of Mycobacterium marinum was studied. We found that inactivation of CpsA altered bacterial colony morphology, sliding motility, cell surface hydrophobicity, and cell wall permeability. Besides, the cpsA mutant exhibited a decreased arabinogalactan content, indicating that CpsA plays a role in cell wall assembly. Moreover, the mutant shows impaired growth within macrophage cell lines and is severely attenuated in zebrafish larvae and adult zebrafish. Taken together, our results indicated that CpsA, a previously uncharacterized protein, is important for mycobacterial cell wall integrity and is required for mycobacterial virulence.
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Modification of the CpsA protein reveals a role in alteration of the Streptococcus agalactiae cell envelope. Infect Immun 2015; 83:1497-506. [PMID: 25644003 DOI: 10.1128/iai.02656-14] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The bacterial cell envelope is a crucial first line of defense for a systemic pathogen, with production of capsular polysaccharides and maintenance of the peptidoglycan cell wall serving essential roles in survival in the host environment. The LytR-CpsA-Psr proteins are important for cell envelope maintenance in many Gram-positive species. In this study, we examined the role of the extracellular domain of the CpsA protein of the zoonotic pathogen group B Streptococcus in capsule production and cell wall integrity. CpsA has multiple functional domains, including a DNA-binding/transcriptional activation domain and a large extracellular domain. We demonstrated that episomal expression of extracellularly truncated CpsA causes a dominant-negative effect on capsule production when expressed in the wild-type strain. Regions of the extracellular domain essential to this phenotype were identified. The dominant-negative effect could be recapitulated by addition of purified CpsA protein or a short CpsA peptide to cultures of wild-type bacteria. Changes in cell wall morphology were also observed when the dominant-negative peptide was added to wild-type cultures. Fluorescently labeled CpsA peptide could be visualized bound at the mid-cell region near the division septae, suggesting a novel role for CpsA in cell division. Finally, expression of truncated CpsA also led to attenuation of virulence in zebrafish models of infection, to levels below that of a cpsA deletion strain, demonstrating the key role of the extracellular domain in virulence of GBS.
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Biology and Assembly of the Bacterial Envelope. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 883:41-76. [PMID: 26621461 DOI: 10.1007/978-3-319-23603-2_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
All free-living bacterial cells are delimited and protected by an envelope of high complexity. This physiological barrier is essential for bacterial survival and assures multiple functions. The molecular assembly of the different envelope components into a functional structure represents a tremendous biological challenge and is of high interest for fundamental sciences. The study of bacterial envelope assembly has also been fostered by the need for novel classes of antibacterial agents to fight the problematic of bacterial resistance to antibiotics. This chapter focuses on the two most intensively studied classes of bacterial envelopes that belong to the phyla Firmicutes and Proteobacteria. The envelope of Firmicutes typically has one membrane and is defined as being monoderm whereas the envelope of Proteobacteria contains two distinct membranes and is referred to as being diderm. In this chapter, we will first discuss the multiple roles of the bacterial envelope and clarify the nomenclature used to describe the different types of envelopes. We will then define the architecture and composition of the envelopes of Firmicutes and Proteobacteria while outlining their similarities and differences. We will further cover the extensive progress made in the field of bacterial envelope assembly over the last decades, using Bacillus subtilis and Escherichia coli as model systems for the study of the monoderm and diderm bacterial envelopes, respectively. We will detail our current understanding of how molecular machines assure the secretion, insertion and folding of the envelope proteins as well as the assembly of the glycosidic components of the envelope. Finally, we will highlight the topics that are still under investigation, and that will surely lead to important discoveries in the near future.
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Abstract
Gram-positive organisms, including the pathogens Staphylococcus aureus, Streptococcus pneumoniae, and Enterococcus faecalis, have dynamic cell envelopes that mediate interactions with the environment and serve as the first line of defense against toxic molecules. Major components of the cell envelope include peptidoglycan (PG), which is a well-established target for antibiotics, teichoic acids (TAs), capsular polysaccharides (CPS), surface proteins, and phospholipids. These components can undergo modification to promote pathogenesis, decrease susceptibility to antibiotics and host immune defenses, and enhance survival in hostile environments. This chapter will cover the structure, biosynthesis, and important functions of major cell envelope components in gram-positive bacteria. Possible targets for new antimicrobials will be noted.
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LytR-CpsA-Psr enzymes as determinants of Bacillus anthracis secondary cell wall polysaccharide assembly. J Bacteriol 2014; 197:343-53. [PMID: 25384480 DOI: 10.1128/jb.02364-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacillus anthracis, the causative agent of anthrax, replicates as chains of vegetative cells by regulating the separation of septal peptidoglycan. Surface (S)-layer proteins and associated proteins (BSLs) function as chain length determinants and bind to the secondary cell wall polysaccharide (SCWP). In this study, we identified the B. anthracis lcpD mutant, which displays increased chain length and S-layer assembly defects due to diminished SCWP attachment to peptidoglycan. In contrast, the B. anthracis lcpB3 variant displayed reduced cell size and chain length, which could be attributed to increased deposition of BSLs. In other bacteria, LytR-CpsA-Psr (LCP) proteins attach wall teichoic acid (WTA) and polysaccharide capsule to peptidoglycan. B. anthracis does not synthesize these polymers, yet its genome encodes six LCP homologues, which, when expressed in S. aureus, promote WTA attachment. We propose a model whereby B. anthracis LCPs promote attachment of SCWP precursors to discrete locations in the peptidoglycan, enabling BSL assembly and regulated separation of septal peptidoglycan.
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Cabrita P, Trigo MJ, Ferreira RB, Brito L. Is the exoproteome important for bacterial pathogenesis? Lessons learned from interstrain exoprotein diversity in Listeria monocytogenes grown at different temperatures. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2014; 18:553-69. [PMID: 25127015 DOI: 10.1089/omi.2013.0151] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Bacterial exoproteomes vary in composition and quantity among species and within each species, depending on the environmental conditions to which the cells are exposed. This article critically reviews the literature available on exoproteins synthesized by the foodborne pathogenic bacterium Listeria monocytogenes grown at different temperatures. The main challenges posed for exoproteome analyses and the strategies that are being used to overcome these constraints are discussed. Over thirty exoproteins from L. monocytogenes are considered, and the multifunctionality of some of them is discussed. Thus, at the host temperature of 37°C, good examples are provided by Lmo0443, a potential marker for low virulence, and by the virulence factors internalin C (InlC) and listeriolysin O (LLO). Based on the reported LLO-induced mucin exocytosis, a model is proposed for the involvement of extracellular LLO in optimizing the conditions for InlC intervention in the invasion of intestinal epithelial cells. At lower growth temperatures, exoproteins such as flagellin (FlaA) and oligopeptide permease (OppA) may explain the persistence of particular strains in the food industry environment, eventually allowing the development of new tools to eradicate L. monocytogenes, a major concern for public health.
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Affiliation(s)
- Paula Cabrita
- 1 CBAA/DRAT-Departamento dos Recursos Naturais, Ambiente e Território, Instituto Superior de Agronomia, University of Lisbon , Lisbon, Portugal
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Solis N, Parker BL, Kwong SM, Robinson G, Firth N, Cordwell SJ. Staphylococcus aureus surface proteins involved in adaptation to oxacillin identified using a novel cell shaving approach. J Proteome Res 2014; 13:2954-72. [PMID: 24708102 DOI: 10.1021/pr500107p] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Staphylococcus aureus is a Gram-positive pathogen responsible for a variety of infections, and some strains are resistant to virtually all classes of antibiotics. Cell shaving proteomics using a novel probability scoring algorithm to compare the surfaceomes of the methicillin-resistant, laboratory-adapted S. aureus COL strain with a COL strain in vitro adapted to high levels of oxacillin (APT). APT displayed altered cell morphology compared with COL and increased aggregation in biofilm assays. Increased resistance to β-lactam antibiotics was observed, but adaptation to oxacillin did not confer multidrug resistance. Analysis of the S. aureus COL and APT surfaceomes identified 150 proteins at a threshold determined by the scoring algorithm. Proteins unique to APT included the LytR-CpsA-Psr (LCP) domain-containing MsrR and SACOL2302. Quantitative RT-PCR showed increased expression of sacol2302 in APT grown with oxacillin (>6-fold compared with COL). Overexpression of sacol2302 in COL to levels consistent with APT (+ oxacillin) did not influence biofilm formation or β-lactam resistance. Proteomics using iTRAQ and LC-MS/MS identified 1323 proteins (∼50% of the theoretical S. aureus proteome), and cluster analysis demonstrated elevated APT abundances of LCP proteins, capsule and peptidoglycan biosynthesis proteins, and proteins involved in wall remodelling. Adaptation to oxacillin also induced urease proteins, which maintained culture pH compared to COL. These results show that S. aureus modifies surface architecture in response to antibiotic adaptation.
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Affiliation(s)
- Nestor Solis
- School of Molecular Bioscience, ‡Discipline of Pathology, School of Medical Sciences, and §School of Biological Sciences, The University of Sydney , New South Wales 2006, Australia
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33
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Chan YGY, Kim HK, Schneewind O, Missiakas D. The capsular polysaccharide of Staphylococcus aureus is attached to peptidoglycan by the LytR-CpsA-Psr (LCP) family of enzymes. J Biol Chem 2014; 289:15680-90. [PMID: 24753256 DOI: 10.1074/jbc.m114.567669] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Envelope biogenesis in bacteria involves synthesis of intermediates that are tethered to the lipid carrier undecaprenol-phosphate. LytR-CpsA-Psr (LCP) enzymes have been proposed to catalyze the transfer of undecaprenol-linked intermediates onto the C6-hydroxyl of MurNAc in peptidoglycan, thereby promoting attachment of wall teichoic acid (WTA) in bacilli and staphylococci and capsular polysaccharides (CPS) in streptococci. S. aureus encodes three lcp enzymes, and a variant lacking all three genes (Δlcp) releases WTA from the bacterial envelope and displays a growth defect. Here, we report that the type 5 capsular polysaccharide (CP5) of Staphylococcus aureus Newman is covalently attached to the glycan strands of peptidoglycan. Cell wall attachment of CP5 is abrogated in the Δlcp variant, a defect that is best complemented via expression of lcpC in trans. CP5 synthesis and peptidoglycan attachment are not impaired in the tagO mutant, suggesting that CP5 synthesis does not involve the GlcNAc-ManNAc linkage unit of WTA and may instead utilize another Wzy-type ligase to assemble undecaprenyl-phosphate intermediates. Thus, LCP enzymes of S. aureus are promiscuous enzymes that attach secondary cell wall polymers with discrete linkage units to peptidoglycan.
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Affiliation(s)
- Yvonne Gar-Yun Chan
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637 and
| | - Hwan Keun Kim
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637 and
| | - Olaf Schneewind
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637 and the Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois 60439
| | - Dominique Missiakas
- From the Department of Microbiology, University of Chicago, Chicago, Illinois 60637 and the Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois 60439
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34
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Bitoun JP, Liao S, Xie GG, Beatty WL, Wen ZT. Deficiency of BrpB causes major defects in cell division, stress responses and biofilm formation by Streptococcus mutans. MICROBIOLOGY-SGM 2013; 160:67-78. [PMID: 24190982 DOI: 10.1099/mic.0.072884-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus mutans, the primary aetiological agent of dental caries, possesses an YjeE-like protein that is encoded by locus SMU.409, herein designated brpB. In this study, a BrpB-deficient mutant, JB409, and a double mutant deficient of BrpB and BrpA (a paralogue of the LytR-CpsA-Psr family of cell wall-associated proteins), JB819, were constructed and characterized using function assays and microscopy analysis. Both JB409 and JB819 displayed extended lag phases and drastically slowed growth rates during growth in brain heart infusion medium as compared to the wild-type, UA159. Relative to UA159, JB409 and JB819 were more than 60- and 10-fold more susceptible to acid killing at pH 2.8, and more than 1 and 2 logs more susceptible to hydrogen peroxide, respectively. Complementation of the deficient mutants with a wild-type copy of the respective gene(s) partly restored the acid and oxidative stress responses to a level similar to the wild-type. As compared to UA159, biofilm formation by JB409 and JB819 was drastically reduced (P<0.001), especially during growth in medium containing sucrose. Under a scanning electron microscope, JB409 had significantly more giant cells with an elongated, rod-like morphology, and JB819 formed marble-like super cells with apparent defects in cell division. As revealed by transmission electron microscopy analysis, BrpB deficiency in both JB409 and JB819 resulted in the development of low electron density patches and formation of a loose nucleoid structure. Taken together, these results suggest that BrpB likely functions together with BrpA in regulating cell envelope biogenesis/homeostasis in Strep. mutans. Further studies are under way to elucidate the mechanism that underlies the BrpA- and BrpB-mediated regulation.
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Affiliation(s)
- Jacob P Bitoun
- Center of Excellence in Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
| | - Sumei Liao
- Center of Excellence in Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
| | - Gary G Xie
- Biology and Bioinformatics, Los Alamos National Laboratory, NM 87545, USA
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110 USA
| | - Zezhang T Wen
- Department of Microbiology, Immunology and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA.,Department of Comprehensive Dentistry and Biomaterials, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA.,Center of Excellence in Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA 70119, USA
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Staphylococcus aureus mutants lacking the LytR-CpsA-Psr family of enzymes release cell wall teichoic acids into the extracellular medium. J Bacteriol 2013; 195:4650-9. [PMID: 23935043 DOI: 10.1128/jb.00544-13] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The LytR-CpsA-Psr (LCP) proteins are thought to transfer bactoprenol-linked biosynthetic intermediates of wall teichoic acid (WTA) to the peptidoglycan of Gram-positive bacteria. In Bacillus subtilis, mutants lacking all three LCP enzymes do not deposit WTA in the envelope, while Staphylococcus aureus Δlcp mutants display impaired growth and reduced levels of envelope phosphate. We show here that the S. aureus Δlcp mutant synthesized WTA yet released ribitol phosphate polymers into the extracellular medium. Further, Δlcp mutant staphylococci no longer restricted the deposition of LysM-type murein hydrolases to cell division sites, which was associated with defects in cell shape and increased autolysis. Mutations in S. aureus WTA synthesis genes (tagB, tarF, or tarJ2) inhibit growth, which is attributed to the depletion of bactoprenol, an essential component of peptidoglycan synthesis (lipid II). The growth defect of S. aureus tagB and tarFJ mutants was alleviated by inhibition of WTA synthesis with tunicamycin, whereas the growth defect of the Δlcp mutant was not relieved by tunicamycin treatment or by mutation of tagO, whose product catalyzes the first committed step of WTA synthesis. Further, sortase A-mediated anchoring of proteins to peptidoglycan, which also involves bactoprenol and lipid II, was not impaired in the Δlcp mutant. We propose a model whereby the S. aureus Δlcp mutant, defective in tethering WTA to the cell wall, cleaves WTA synthesis intermediates, releasing ribitol phosphate into the medium and recycling bactoprenol for peptidoglycan synthesis.
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36
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Quiblier C, Seidl K, Roschitzki B, Zinkernagel AS, Berger-Bächi B, Senn MM. Secretome analysis defines the major role of SecDF in Staphylococcus aureus virulence. PLoS One 2013; 8:e63513. [PMID: 23658837 PMCID: PMC3643904 DOI: 10.1371/journal.pone.0063513] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 04/02/2013] [Indexed: 01/27/2023] Open
Abstract
The Sec pathway plays a prominent role in protein export and membrane insertion, including the secretion of major bacterial virulence determinants. The accessory Sec constituent SecDF has been proposed to contribute to protein export. Deletion of Staphylococcus aureus secDF has previously been shown to reduce resistance, to alter cell separation, and to change the expression of certain virulence factors. To analyse the impact of the secDF deletion in S. aureus on protein secretion, a quantitative secretome analysis was performed. Numerous Sec signal containing proteins involved in virulence were found to be decreased in the supernatant of the secDF mutant. However, two Sec-dependent hydrolases were increased in comparison to the wild type, suggesting additional indirect, regulatory effects to occur upon deletion of secDF. Adhesion, invasion, and cytotoxicity of the secDF mutant were reduced in human umbilical vein endothelial cells. Virulence was significantly reduced using a Galleria mellonella insect model. Altogether, SecDF is a promising therapeutic target for controlling S. aureus infections.
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Affiliation(s)
- Chantal Quiblier
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Kati Seidl
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bernd Roschitzki
- Functional Genomics Center Zurich, Swiss Federal Institute of Technology and University of Zurich, Zurich, Switzerland
| | - Annelies S. Zinkernagel
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | | | - Maria M. Senn
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
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The Staphylococcus aureus Membrane Protein SA2056 Interacts with Peptidoglycan Synthesis Enzymes. Antibiotics (Basel) 2013; 2:11-27. [PMID: 27029289 PMCID: PMC4790295 DOI: 10.3390/antibiotics2010011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 01/16/2013] [Accepted: 01/16/2013] [Indexed: 12/12/2022] Open
Abstract
The yet uncharacterized membrane protein SA2056 belongs to the ubiquitous RND (Resistance-Nodulation-cell Division) family of transmembrane efflux transporters. The sa2056 gene is located downstream of femX, the gene encoding the essential, non-ribosomal peptidyl-transferase adding the first glycine in the staphylococcal cell wall pentaglycine interpeptide. Due to its proximity to and weak co-transcription with femX, we assumed that sa2056 may somehow be involved in peptidoglycan synthesis. Specific antibodies against SA2056 showed that this protein is expressed during growth and present in the membrane fraction of cell preparations. Using a bacterial two hybrid system, SA2056 was shown to interact (i) with itself, (ii) with FemB, which adds glycines 4 and 5 to the peptidoglycan interpeptide and (iii) with the essential penicillin binding proteins, PBP1 and PBP2, required for cell division and incorporation of the peptidoglycan into the cell wall. Unexpectedly, deletion of sa2056 led to no phenotype regarding growth, antibiotic resistances or cell morphology; nor did sa2056 deletion in combination with femB inactivation alter β-lactam and lysostaphin sensitivity and resistance, respectively, pointing to possible redundancy in the cell wall synthesis pathway. These results suggest an accessory role of SA2056 in S. aureus peptidoglycan synthesis, broadening the range of biological functions of RND proteins.
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38
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Bitoun JP, Liao S, McKey BA, Yao X, Fan Y, Abranches J, Beatty WL, Wen ZT. Psr is involved in regulation of glucan production, and double deficiency of BrpA and Psr is lethal in Streptococcus mutans. MICROBIOLOGY-SGM 2013; 159:493-506. [PMID: 23288544 DOI: 10.1099/mic.0.063032-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Streptococcus mutans, the primary causative agent of dental caries, contains two paralogues of the LytR-CpsA-Psr family proteins encoded by brpA and psr, respectively. Previous studies have shown that BrpA plays an important role in cell envelope biogenesis/homeostasis and affects stress responses and biofilm formation by Strep. mutans, traits critical to cariogenicity of this bacterium. In this study, a Psr-deficient mutant, TW251, was constructed. Characterization of TW251 showed that deficiency of Psr did not have any major impact on growth rate. However, when subjected to acid killing at pH 2.8, the survival rate of TW251 was decreased dramatically compared with the parent strain UA159. In addition, TW251 also displayed major defects in biofilm formation, especially during growth with sucrose. When compared to UA159, the biofilms of TW251 were mainly planar and devoid of extracellular glucans. Real-time-PCR and Western blot analyses revealed that deficiency of Psr significantly decreased the expression of glucosyltransferase C, a protein known to play a major role in biofilm formation by Strep. mutans. Transmission electron microscopy analysis showed that deficiency of BrpA caused alterations in cell envelope and cell division, and the most significant defects were observed in TW314, a Psr-deficient and BrpA-down mutant. No such effects were observed with Psr mutant TW251 under similar conditions. These results suggest that while there are similarities in functions between BrpA and Psr, distinctive differences also exist between these two paralogues. Like Bacillus subtilis but different from Staphylococcus aureus, a functional BrpA or Psr is required for viability in Strep. mutans.
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Affiliation(s)
- Jacob P Bitoun
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Sumei Liao
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Briggs A McKey
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Xin Yao
- Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Yuwei Fan
- Department of Comprehensive Dentistry and Biomaterials, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Jacqueline Abranches
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Wandy L Beatty
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
| | - Zezhang T Wen
- Department of Microbiology, Immunology, and Parasitology, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, LA, USA.,Department of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, LA, USA
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Abstract
The peptidoglycan layers of many gram-positive bacteria are densely functionalized with anionic glycopolymers known as wall teichoic acids (WTAs). These polymers play crucial roles in cell shape determination, regulation of cell division, and other fundamental aspects of gram-positive bacterial physiology. Additionally, WTAs are important in pathogenesis and play key roles in antibiotic resistance. We provide an overview of WTA structure and biosynthesis, review recent studies on the biological roles of these polymers, and highlight remaining questions. We also discuss prospects for exploiting WTA biosynthesis as a target for new therapies to overcome resistant infections.
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Affiliation(s)
- Stephanie Brown
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115;
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40
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Dengler V, Meier PS, Heusser R, Kupferschmied P, Fazekas J, Friebe S, Staufer SB, Majcherczyk PA, Moreillon P, Berger-Bächi B, McCallum N. Deletion of hypothetical wall teichoic acid ligases in Staphylococcus aureus activates the cell wall stress response. FEMS Microbiol Lett 2012; 333:109-20. [PMID: 22640011 DOI: 10.1111/j.1574-6968.2012.02603.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 04/25/2012] [Accepted: 05/21/2012] [Indexed: 11/30/2022] Open
Abstract
The Staphylococcus aureus cell wall stress stimulon (CWSS) is activated by cell envelope-targeting antibiotics or depletion of essential cell wall biosynthesis enzymes. The functionally uncharacterized S. aureus LytR-CpsA-Psr (LCP) proteins, MsrR, SA0908 and SA2103, all belong to the CWSS. Although not essential, deletion of all three LCP proteins severely impairs cell division. We show here that VraSR-dependent CWSS expression was up to 250-fold higher in single, double and triple LCP mutants than in wild type S. aureus in the absence of external stress. The LCP triple mutant was virtually depleted of wall teichoic acids (WTA), which could be restored to different degrees by any of the single LCP proteins. Subinhibitory concentrations of tunicamycin, which inhibits the first WTA synthesis enzyme TarO (TagO), could partially complement the severe growth defect of the LCP triple mutant. Both of the latter findings support a role for S. aureus LCP proteins in late WTA synthesis, as in Bacillus subtilis where LCP proteins were recently proposed to transfer WTA from lipid carriers to the cell wall peptidoglycan. Intrinsic activation of the CWSS upon LCP deletion and the fact that LCP proteins were essential for WTA-loading of the cell wall, highlight their important role(s) in S. aureus cell envelope biogenesis.
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Affiliation(s)
- Vanina Dengler
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland.
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41
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BrpA is involved in regulation of cell envelope stress responses in Streptococcus mutans. Appl Environ Microbiol 2012; 78:2914-22. [PMID: 22327589 DOI: 10.1128/aem.07823-11] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous studies have shown that BrpA plays a major role in acid and oxidative stress tolerance and biofilm formation by Streptococcus mutans. Mutant strains lacking BrpA also display increased autolysis and decreased viability, suggesting a role for BrpA in cell envelope integrity. In this study, we examined the impact of BrpA deficiency on cell envelope stresses induced by envelope-active antimicrobials. Compared to the wild-type strain UA159, the BrpA-deficient mutant (TW14D) was significantly more susceptible to antimicrobial agents, especially lipid II inhibitors. Several genes involved in peptidoglycan synthesis were identified by DNA microarray analysis as downregulated in TW14D. Luciferase reporter gene fusion assays also revealed that expression of brpA is regulated in response to environmental conditions and stresses induced by exposure to subinhibitory concentrations of cell envelope antimicrobials. In a Galleria mellonella (wax worm) model, BrpA deficiency was shown to diminish the virulence of S. mutans OMZ175, which, unlike S. mutans UA159, efficiently kills the worms. Collectively, these results suggest that BrpA plays a role in the regulation of cell envelope integrity and that deficiency of BrpA adversely affects the fitness and diminishes the virulence of OMZ175, a highly invasive strain of S. mutans.
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42
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Abstract
Streptococcal pathogens, such as the group B streptococcus (GBS) Streptococcus agalactiae, are an important cause of systemic disease, which is facilitated in part by the presence of a polysaccharide capsule. The CpsA protein is a putative transcriptional regulator of the capsule locus, but its exact contribution to regulation is unknown. To address the role of CpsA in regulation, full-length GBS CpsA and two truncated forms of the protein were purified and analyzed for DNA-binding ability. Assays demonstrated that CpsA is able to bind specifically to two putative promoters within the capsule operon with similar affinity, and full-length protein is required for specificity. Functional characterization of CpsA confirmed that the ΔcpsA strain produced less capsule than did the wild type and demonstrated that the production of full-length CpsA or the DNA-binding region of CpsA resulted in increased capsule levels. In contrast, the production of a truncated form of CpsA lacking the extracellular LytR domain (CpsA-245) in the wild-type background resulted in a dominant-negative decrease in capsule production. GBS expressing CpsA-245, but not the ΔcpsA strain, was attenuated in human whole blood. However, the ΔcpsA strain showed significant attenuation in a zebrafish infection model. Furthermore, chain length was observed to be variable in a CpsA-dependent manner, but could be restored to wild-type levels when grown with lysozyme. Taken together, these results suggest that CpsA is a modular protein influencing multiple regulatory functions that may include not only capsule synthesis but also cell wall associated factors.
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43
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Hanson BR, Neely MN. Coordinate regulation of Gram-positive cell surface components. Curr Opin Microbiol 2012; 15:204-10. [PMID: 22236805 DOI: 10.1016/j.mib.2011.12.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/16/2011] [Accepted: 12/22/2011] [Indexed: 01/07/2023]
Abstract
The cell surface of Gram-positive pathogens represents a complex association of glycopolymers that control cell division, homeostasis, immune evasion, tissue invasion, and resistance to antimicrobials. These glycopolymers include the peptidoglycan cell wall, wall-teichoic acids, lipoteichoic acids, and capsular polysaccharide. Disruption of individual factors often results in pleiotropic effects, making it difficult to discern regulation and function. In this review we collate recent work describing these pleiotropic phenotypes, and propose that this is due to coordinated regulation of biosynthesis or modification of these cell surface components. A better understanding of the regulatory networks that control the relative prevalence of each factor on the cell surface or their modulated functions may help facilitate the identification of new targets for antimicrobial therapy.
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Affiliation(s)
- Brett R Hanson
- Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
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