1
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Kanakapura Sundararaj B, Goyal M, Samuelson J. Cellulose binding and the timing of expression influence protein targeting to the double-layered cyst wall of Acanthamoeba. mSphere 2024; 9:e0046624. [PMID: 39136454 PMCID: PMC11423589 DOI: 10.1128/msphere.00466-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 07/22/2024] [Indexed: 09/26/2024] Open
Abstract
The cyst wall of the eye pathogen Acanthamoeba castellanii contains cellulose and has ectocyst and endocyst layers connected by conical ostioles. Cyst walls contain families of lectins that localize to the ectocyst layer (Jonah) or the endocyst layer and ostioles (Luke and Leo). How lectins and an abundant laccase bind cellulose and why proteins go to locations in the wall are not known and are the focus of the studies here. Structural predictions identified β-jelly-roll folds (BJRFs) of Luke and sets of four disulfide knots (4DKs) of Leo, each of which contains linear arrays of aromatic amino acids, also present in carbohydrate-binding modules of bacterial and plant endocellulases. Ala mutations showed that these aromatics are necessary for cellulose binding and proper localization of Luke and Leo in the Acanthamoeba cyst wall. BJRFs of Luke, 4DKs of Leo, a single β-helical fold (BHF) of Jonah, and a copper oxidase domain of the laccase each bind to glycopolymers in both layers of deproteinated cyst walls. Promoter swaps showed that ectocyst localization does not just correlate with but is caused by early encystation-specific expression, while localization in the endocyst layer and ostioles is caused by later expression. Evolutionary studies showed distinct modes of assembly of duplicated domains in Luke, Leo, and Jonah lectins and suggested Jonah BHFs originated from bacteria, Luke BJRFs share common ancestry with slime molds, while 4DKs of Leo are unique to Acanthamoeba.IMPORTANCEAcanthamoebae is the only human parasite with cellulose in its cyst wall and conical ostioles that connect its inner and outer layers. Cyst walls are important virulence factors because they make Acanthamoebae resistant to surface disinfectants, hand sanitizers, contact lens sterilizers, and antibiotics applied to the eye. The goal here was to understand better how proteins are targeted to specific locations in the cyst wall. To this end, we identified three new proteins in the outer layer of the cyst wall, which may be targets for diagnostic antibodies in corneal scrapings. We used structural predictions and mutated proteins to show linear arrays of aromatic amino acids of two unrelated wall proteins are necessary for binding cellulose and proper wall localization. We showed early expression during encystation causes proteins to localize to the outer layer, while later expression causes proteins to localize to the inner layer and the ostioles.
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Affiliation(s)
- Bharath Kanakapura Sundararaj
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, USA
| | - Manish Goyal
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, USA
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, USA
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2
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Zackova Suchanova J, Bilcke G, Romanowska B, Fatlawi A, Pippel M, Skeffington A, Schroeder M, Vyverman W, Vandepoele K, Kröger N, Poulsen N. Diatom adhesive trail proteins acquired by horizontal gene transfer from bacteria serve as primers for marine biofilm formation. THE NEW PHYTOLOGIST 2023; 240:770-783. [PMID: 37548082 DOI: 10.1111/nph.19145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 07/02/2023] [Indexed: 08/08/2023]
Abstract
Biofilm-forming benthic diatoms are key primary producers in coastal habitats, where they frequently dominate sunlit intertidal substrata. The development of gliding motility in raphid diatoms was a key molecular adaptation that contributed to their evolutionary success. However, the structure-function correlation between diatom adhesives utilized for gliding and their relationship to the extracellular matrix that constitutes the diatom biofilm is unknown. Here, we have used proteomics, immunolocalization, comparative genomics, phylogenetics and structural homology analysis to investigate the evolutionary history and function of diatom adhesive proteins. Our study identified eight proteins from the adhesive trails of Craspedostauros australis, of which four form a new protein family called Trailins that contain an enigmatic Choice-of-Anchor A (CAA) domain, which was acquired through horizontal gene transfer from bacteria. Notably, the CAA-domain shares a striking structural similarity with one of the most widespread domains found in ice-binding proteins (IPR021884). Our work offers new insights into the molecular basis for diatom biofilm formation, shedding light on the function and evolution of diatom adhesive proteins. This discovery suggests that there is a transition in the composition of biomolecules required for initial surface colonization and those utilized for 3D biofilm matrix formation.
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Affiliation(s)
- Jirina Zackova Suchanova
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, 01307, Germany
| | - Gust Bilcke
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Beata Romanowska
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, 01307, Germany
| | - Ali Fatlawi
- Biotechnology Center (BIOTEC), Technische Universität Dresden, Tatzberg 47-49, Dresden, 01307, Germany
- Centre for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI), Chemnitzer Str. 46b, Dresden, 01187, Germany
| | - Martin Pippel
- Max Planck Institute of Molecular Cell Biology and Genetics, Germany Center for Systems Biology, Pfotenhauerstraße 108, Dresden, 01307, Germany
| | - Alastair Skeffington
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, FK9 4LA, UK
| | - Michael Schroeder
- Biotechnology Center (BIOTEC), Technische Universität Dresden, Tatzberg 47-49, Dresden, 01307, Germany
- Centre for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI), Chemnitzer Str. 46b, Dresden, 01187, Germany
| | - Wim Vyverman
- Department of Biology, Protistology and Aquatic Ecology, Ghent University, Ghent, 9000, Belgium
| | - Klaas Vandepoele
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, Ghent, 9052, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, Ghent, 9052, Belgium
| | - Nils Kröger
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, 01307, Germany
- Cluster of Excellence Physics of Life, Technische Universität Dresden, Dresden, 01062, Germany
- Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Dresden, 01062, Germany
| | - Nicole Poulsen
- B CUBE Center for Molecular Bioengineering, Technische Universität Dresden, Dresden, 01307, Germany
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3
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Large-Scale Discovery of Microbial Fibrillar Adhesins and Identification of Novel Members of Adhesive Domain Families. J Bacteriol 2022; 204:e0010722. [PMID: 35608365 PMCID: PMC9210967 DOI: 10.1128/jb.00107-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Fibrillar adhesins are bacterial cell surface proteins that mediate interactions with the environment, including host cells during colonization or other bacteria during biofilm formation. These proteins are characterized by a stalk that projects the adhesive domain closer to the binding target. Fibrillar adhesins evolve quickly and thus can be difficult to computationally identify, yet they represent an important component for understanding bacterium-host interactions. To detect novel fibrillar adhesins, we developed a random forest prediction approach based on common characteristics we identified for this protein class. We applied this approach to Firmicutes and Actinobacteria proteomes, yielding over 6,500 confidently predicted fibrillar adhesins. To verify the approach, we investigated predicted fibrillar adhesins that lacked a known adhesive domain. Based on these proteins, we identified 24 sequence clusters representing potential novel members of adhesive domain families. We used AlphaFold to verify that 15 clusters showed structural similarity to known adhesive domains, such as the TED domain. Overall, our study has made a significant contribution to the number of known fibrillar adhesins and has enabled us to identify novel members of adhesive domain families involved in bacterial pathogenesis. IMPORTANCE Fibrillar adhesins are a class of bacterial cell surface proteins that enable bacteria to interact with their environment. We developed a machine learning approach to identify fibrillar adhesins and applied this classification approach to the Firmicutes and Actinobacteria Reference Proteomes database. This method allowed us to detect a high number of novel fibrillar adhesins and also novel members of adhesive domain families. To confirm our predictions of these potential adhesin protein domains, we predicted their structure using the AlphaFold tool.
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4
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De Gaetano GV, Coppolino F, Lentini G, Famà A, Cullotta C, Raffaele I, Motta C, Teti G, Speziale P, Pietrocola G, Beninati C. Streptococcus pneumoniae
binds collagens and C1q
via
the SSURE repeats of the PfbB adhesin. Mol Microbiol 2022; 117:1479-1492. [PMID: 35570359 PMCID: PMC9328315 DOI: 10.1111/mmi.14920] [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: 12/14/2021] [Revised: 04/17/2022] [Accepted: 05/12/2022] [Indexed: 11/29/2022]
Abstract
The binding of Streptococcus pneumoniae to collagen is likely an important step in the pathogenesis of pneumococcal infections, but little is known of the underlying molecular mechanisms. Streptococcal surface repeats (SSURE) are highly conserved protein domains present in cell wall adhesins from different Streptococcus species. We find here that SSURE repeats of the pneumococcal adhesin plasminogen and fibronectin binding protein B (PfbB) bind to various types of collagen. Moreover, deletion of the pfbB gene resulted in a significant impairment of the ability of encapsulated or unencapsulated pneumococci to bind collagen. Notably, a PfbB SSURE domain is also bound to the complement component C1q that bears a collagen‐like domain and promotes adherence of pneumococci to host cells by acting as a bridge between bacteria and epithelial cells. Accordingly, deletion of PfbB or pre‐treatment with anti‐SSURE antibodies markedly decreased pneumococcal binding to C1q as well as C1q‐dependent adherence to epithelial and endothelial cells. Further data indicated that C1q promotes pneumococcal adherence by binding to integrin α2β1. In conclusion, our results indicate that the SSURE domains of the PfbB protein promote interactions of pneumococci with various types of collagen and with C1q. These repeats may be useful targets in strategies to control S. pneumoniae infections.
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Affiliation(s)
| | - Francesco Coppolino
- Department of BiomedicalDental and Imaging SciencesUniversity of MessinaMessinaItaly
| | - Germana Lentini
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Agata Famà
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Chiara Cullotta
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Ivana Raffaele
- Department of Human PathologyUniversity of MessinaMessinaItaly
| | - Chiara Motta
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | | | - Pietro Speziale
- Department of Molecular MedicineUniversity of PaviaPaviaItaly
| | | | - Concetta Beninati
- Department of Human PathologyUniversity of MessinaMessinaItaly
- Scylla Biotech SrlMessinaItaly
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5
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Arora S, Gordon J, Hook M. Collagen Binding Proteins of Gram-Positive Pathogens. Front Microbiol 2021; 12:628798. [PMID: 33613497 PMCID: PMC7893114 DOI: 10.3389/fmicb.2021.628798] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
Collagens are the primary structural components of mammalian extracellular matrices. In addition, collagens regulate tissue development, regeneration and host defense through interaction with specific cellular receptors. Their unique triple helix structure, which requires a glycine residue every third amino acid, is the defining structural feature of collagens. There are 28 genetically distinct collagens in humans. In addition, several other unrelated human proteins contain a collagen domain. Gram-positive bacteria of the genera Staphylococcus, Streptococcus, Enterococcus, and Bacillus express cell surface proteins that bind to collagen. These proteins of Gram-positive pathogens are modular proteins that can be classified into different structural families. This review will focus on the different structural families of collagen binding proteins of Gram-positive pathogen. We will describe how these proteins interact with the triple helix in collagens and other host proteins containing a collagenous domain and discuss how these interactions can contribute to the pathogenic processes.
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Affiliation(s)
- Srishtee Arora
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Jay Gordon
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
| | - Magnus Hook
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX, United States
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6
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Chateau A, Van der Verren SE, Remaut H, Fioravanti A. The Bacillus anthracis Cell Envelope: Composition, Physiological Role, and Clinical Relevance. Microorganisms 2020; 8:E1864. [PMID: 33255913 PMCID: PMC7759979 DOI: 10.3390/microorganisms8121864] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 12/31/2022] Open
Abstract
Anthrax is a highly resilient and deadly disease caused by the spore-forming bacterial pathogen Bacillus anthracis. The bacterium presents a complex and dynamic composition of its cell envelope, which changes in response to developmental and environmental conditions and host-dependent signals. Because of their easy to access extracellular locations, B. anthracis cell envelope components represent interesting targets for the identification and development of novel therapeutic and vaccine strategies. This review will focus on the novel insights regarding the composition, physiological role, and clinical relevance of B. anthracis cell envelope components.
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Affiliation(s)
- Alice Chateau
- Avignon Université, INRAE, UMR SQPOV, F-84914 Avignon, France;
| | - Sander E. Van der Verren
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, 1050 Brussels, Belgium; (S.E.V.d.V.); (H.R.)
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Han Remaut
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, 1050 Brussels, Belgium; (S.E.V.d.V.); (H.R.)
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Antonella Fioravanti
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, 1050 Brussels, Belgium; (S.E.V.d.V.); (H.R.)
- Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
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7
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Benn JS, Chaki SP, Xu Y, Ficht TA, Rice-Ficht AC, Cook WE. Protective antibody response following oral vaccination with microencapsulated Bacillus Anthracis Sterne strain 34F2 spores. NPJ Vaccines 2020; 5:59. [PMID: 32685200 PMCID: PMC7351773 DOI: 10.1038/s41541-020-0208-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 06/05/2020] [Indexed: 11/30/2022] Open
Abstract
An oral vaccine against anthrax (Bacillus anthracis) is urgently needed to prevent annual anthrax outbreaks that are causing catastrophic losses in free-ranging livestock and wildlife worldwide. The Sterne vaccine, the current injectable livestock vaccine, is a suspension of live attenuated B. anthracis Sterne strain 34F2 spores (Sterne spores) in saponin. It is not effective when administered orally and individual subcutaneous injections are not a practical method of vaccination for wildlife. In this study, we report the development of a microencapsulated oral vaccine against anthrax. Evaluating Sterne spore stability at varying pH's in vitro revealed that spore exposure to pH 2 results in spore death, confirming that protection from the gastric environment is of main concern when producing an oral vaccine. Therefore, Sterne spores were encapsulated in alginate and coated with a protein shell containing poly-L-lysine (PLL) and vitelline protein B (VpB), a non-immunogenic, proteolysis resistant protein isolated from Fasciola hepatica. Capsule exposure to pH 2 demonstrated enhanced acid gel character suggesting that alginate microcapsules provided the necessary protection for spores to survive the gastric environment. Post vaccination IgG levels in BALBc/J mouse serum samples indicated that encapsulated spores induced anti-anthrax specific responses in both the subcutaneous and the oral vaccination groups. Furthermore, the antibody responses from both vaccination routes were protective against anthrax lethal toxin in vitro, suggesting that further optimization of this vaccine formulation may result in a reliable oral vaccine that will conveniently and effectively prevent anthrax in wildlife populations.
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Affiliation(s)
- Jamie S. Benn
- Texas A&M University, Department of Veterinary Pathobiology, College Station, TX 77843 USA
| | - Sankar P. Chaki
- Texas A&M University, Department of Veterinary Pathobiology, College Station, TX 77843 USA
| | - Yi Xu
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030 USA
| | - Thomas A. Ficht
- Texas A&M University, Department of Veterinary Pathobiology, College Station, TX 77843 USA
| | - Allison C. Rice-Ficht
- Texas A&M University, Department of Veterinary Pathobiology, College Station, TX 77843 USA
- Texas A&M Health Science Center, Department of Molecular and Cellular Medicine, College Station, TX 77843 USA
| | - Walter E. Cook
- Texas A&M University, Department of Veterinary Pathobiology, College Station, TX 77843 USA
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8
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Lachnit M, Buhmann MT, Klemm J, Kröger N, Poulsen N. Identification of proteins in the adhesive trails of the diatom Amphora coffeaeformis. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190196. [PMID: 31495312 DOI: 10.1098/rstb.2019.0196] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Throughout all kingdoms of life, a large number of adhesive biomolecules have evolved to allow organisms to adhere to surfaces underwater. Proteins play an important role in the adhesion of numerous marine invertebrates (e.g. mussels, sea stars, sea urchins) whereas much less is known about the biological adhesives from marine plants, including the diatoms. Diatoms are unicellular microalgae that together with bacteria dominate marine biofilms in sunlit habitats. In this study we present the first proteomics analyses of the diatom adhesive material isolated from the tenacious fouling species Amphora coffeaeformis. We identified 21 proteins, of which 13 are diatom-specific. Ten of these proteins share a conserved C-terminal domain, termed GDPH domain, which is widespread yet not ubiquitously present in all diatom classes. Immunofluorescence localization of a GDPH domain bearing protein (Ac629) as well as two other proteins identified in this study (Ac1442, Ac9617) demonstrated that these are components of the adhesive trails that are secreted by cells that glide on surfaces. This article is part of the theme issue 'Transdisciplinary approaches to the study of adhesion and adhesives in biological systems'.
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Affiliation(s)
- Martina Lachnit
- B CUBE, Technical University of Dresden, Tatzberg 41, 01307 Dresden, Germany
| | - Matthias T Buhmann
- B CUBE, Technical University of Dresden, Tatzberg 41, 01307 Dresden, Germany
| | - Jennifer Klemm
- B CUBE, Technical University of Dresden, Tatzberg 41, 01307 Dresden, Germany
| | - Nils Kröger
- B CUBE, Technical University of Dresden, Tatzberg 41, 01307 Dresden, Germany
| | - Nicole Poulsen
- B CUBE, Technical University of Dresden, Tatzberg 41, 01307 Dresden, Germany
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9
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Finke S, Fagerlund A, Smith V, Krogstad V, Zhang MJ, Saragliadis A, Linke D, Nielsen-LeRoux C, Økstad OA. Bacillus thuringiensis CbpA is a collagen binding cell surface protein under c-di-GMP control. ACTA ACUST UNITED AC 2019; 5:100032. [PMID: 32803021 PMCID: PMC7423583 DOI: 10.1016/j.tcsw.2019.100032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 06/24/2019] [Accepted: 07/05/2019] [Indexed: 12/12/2022]
Abstract
Cyclic diguanylate (c-di-GMP) signalling affects several cellular processes in Bacillus cereus group bacteria including biofilm formation and motility, and CdgF was previously identified as a diguanylate cyclase promoting biofilm formation in B. thuringiensis. C-di-GMP can exert its function as a second messenger via riboswitch binding, and a functional c-di-GMP-responsive riboswitch has been found upstream of cbpA in various B. cereus group strains. Protein signature recognition predicted CbpA to be a cell wall-anchored surface protein with a fibrinogen or collagen binding domain. The aim of this study was to identify the binding ligand of CbpA and the function of CbpA in cellular processes that are part of the B. cereus group c-di-GMP regulatory network. By global gene expression profiling cbpA was found to be down-regulated in a cdgF deletion mutant, and cbpA exhibited maximum expression in early exponential growth. Contrary to the wild type, a ΔcbpA deletion mutant showed no binding to collagen in a cell adhesion assay, while a CbpA overexpression strain exhibited slightly increased collagen binding compared to the control. For both fibrinogen and fibronectin there was however no change in binding activity compared to controls, and CbpA did not appear to contribute to binding to abiotic surfaces (polystyrene, glass, steel). Also, the CbpA overexpression strain appeared to be less motile and showed a decrease in biofilm formation compared to the control. This study provides the first experimental proof that the binding ligand of the c-di-GMP regulated adhesin CbpA is collagen.
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Affiliation(s)
- Sarah Finke
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Annette Fagerlund
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Veronika Smith
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Veronica Krogstad
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | - Mimmi Jingxi Zhang
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
| | | | - Dirk Linke
- Department of Biosciences, University of Oslo, Norway
| | | | - Ole Andreas Økstad
- Centre for Integrative Microbial Evolution and Section for Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, Norway
- Corresponding author at: Department of Pharmacy, University of Oslo, PB 1068 Blindern, 0371 Blindern, Norway.
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10
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Magistrado-Coxen P, Aqeel Y, Lopez A, Haserick JR, Urbanowicz BR, Costello CE, Samuelson J. The most abundant cyst wall proteins of Acanthamoeba castellanii are lectins that bind cellulose and localize to distinct structures in developing and mature cyst walls. PLoS Negl Trop Dis 2019; 13:e0007352. [PMID: 31095564 PMCID: PMC6541295 DOI: 10.1371/journal.pntd.0007352] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/29/2019] [Accepted: 04/01/2019] [Indexed: 12/02/2022] Open
Abstract
Background Acanthamoeba castellanii, which causes keratitis and blindness in under-resourced countries, is an emerging pathogen worldwide, because of its association with contact lens use. The wall makes cysts resistant to sterilizing reagents in lens solutions and to antibiotics applied to the eye. Methodology/Principal findings Transmission electron microscopy and structured illumination microscopy (SIM) showed purified cyst walls of A. castellanii retained an outer ectocyst layer, an inner endocyst layer, and conical ostioles that connect them. Mass spectrometry showed candidate cyst wall proteins were dominated by three families of lectins (named here Jonah, Luke, and Leo), which bound well to cellulose and less well to chitin. An abundant Jonah lectin, which has one choice-of-anchor A (CAA) domain, was made early during encystation and localized to the ectocyst layer of cyst walls. An abundant Luke lectin, which has two carbohydrate-binding modules (CBM49), outlined small, flat ostioles in a single-layered primordial wall and localized to the endocyst layer and ostioles of mature walls. An abundant Leo lectin, which has two unique domains with eight Cys residues each (8-Cys), localized to the endocyst layer and ostioles. The Jonah lectin and glycopolymers, to which it binds, were accessible in the ectocyst layer. In contrast, Luke and Leo lectins and the glycopolymers, to which they bind, were mostly inaccessible in the endocyst layer and ostioles. Conclusions/Significance The most abundant A. castellanii cyst wall proteins are three sets of lectins, which have carbohydrate-binding modules that are conserved (CBM49s of Luke), newly characterized (CAA of Jonah), or unique to Acanthamoebae (8-Cys of Leo). Cyst wall formation is a tightly choreographed event, in which lectins and glycopolymers combine to form a mature wall with a protected endocyst layer. Because of its accessibility in the ectocyst layer, an abundant Jonah lectin is an excellent diagnostic target. A half century ago, investigators identified cellulose in the Acanthamoeba cyst wall, which has two layers and conical ostioles that connect them. Here we showed cyst walls contain three large sets of cellulose-binding lectins, which localize to the ectocyst layer (a Jonah lectin) or to the endocyst layer and ostioles (Luke and Leo lectins). We used the lectins to establish a sequence for cyst wall assembly when trophozoites are starved and encyst. In the first stage, a Jonah lectin and glycopolymers were present in dozens of distinct vesicles. In the second stage, a primordial wall contained small, flat ostioles outlined by a Luke lectin. In the third stage, a Jonah lectin remained in the ectocyst layer, while Luke and Leo lectins moved to the endocyst layer and ostioles. A description of the major events during cyst wall development is a starting point for mechanistic studies of its assembly.
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Affiliation(s)
- Pamela Magistrado-Coxen
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
| | - Yousuf Aqeel
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
| | - Angelo Lopez
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - John R. Haserick
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Breeanna R. Urbanowicz
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, United States of America
| | - Catherine E. Costello
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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11
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Candela T, Fagerlund A, Buisson C, Gilois N, Kolstø AB, Økstad OA, Aymerich S, Nielsen-Leroux C, Lereclus D, Gohar M. CalY is a major virulence factor and a biofilm matrix protein. Mol Microbiol 2019; 111:1416-1429. [PMID: 30548239 DOI: 10.1111/mmi.14184] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/04/2018] [Indexed: 12/16/2022]
Abstract
The extracellular biofilm matrix often contains a network of amyloid fibers which, in the human opportunistic pathogen Bacillus cereus, includes the two homologous proteins TasA and CalY. We show here, in the closely related entomopathogenic species Bacillus thuringiensis, that CalY also displays a second function. In the early stationary phase of planktonic cultures, CalY was located at the bacterial cell-surface, as shown by immunodetection. Deletion of calY revealed that this protein plays a major role in adhesion to HeLa epithelial cells, to the insect Galleria mellonella hemocytes and in the bacterial virulence against larvae of this insect, suggesting that CalY is a cell-surface adhesin. In mid-stationary phase and in biofilms, the location of CalY shifted from the cell surface to the extracellular medium, where it was found as fibers. The transcription study and the deletion of sipW suggested that CalY change of location is due to a delayed activity of the SipW signal peptidase. Using purified CalY, we found that the protein polymerization occurred only in the presence of cell-surface components. CalY is, therefore, a bifunctional protein, which switches from a cell-surface adhesin activity in early stationary phase, to the production of fibers in mid-stationary phase and in biofilms.
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Affiliation(s)
- Thomas Candela
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Annette Fagerlund
- Laboratory for Microbial Dynamics, School of Pharmacy and Centre for Integrative Microbial Evolution, University of Oslo, Oslo, Norway
| | - Christophe Buisson
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Nathalie Gilois
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Anne-Brit Kolstø
- Laboratory for Microbial Dynamics, School of Pharmacy and Centre for Integrative Microbial Evolution, University of Oslo, Oslo, Norway
| | - Ole Andreas Økstad
- Laboratory for Microbial Dynamics, School of Pharmacy and Centre for Integrative Microbial Evolution, University of Oslo, Oslo, Norway
| | - Stéphane Aymerich
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | | | - Didier Lereclus
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Michel Gohar
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
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12
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Miller OK, Banfield MJ, Schwarz-Linek U. A new structural class of bacterial thioester domains reveals a slipknot topology. Protein Sci 2018; 27:1651-1660. [PMID: 30052296 PMCID: PMC6194298 DOI: 10.1002/pro.3478] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 06/28/2018] [Accepted: 06/28/2018] [Indexed: 11/11/2022]
Abstract
An increasing number of surface-associated proteins identified in Gram-positive bacteria are characterized by intramolecular cross-links in structurally conserved thioester, isopeptide, and ester domains (TIE proteins). Two classes of thioester domains (TEDs) have been predicted based on sequence with, to date, only representatives of Class I structurally characterized. Here, we present crystal structures of three Class II TEDs from Bacillus anthracis, vancomycin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium. These proteins are structurally distinct from Class I TEDs due to a β-sandwich domain that is inserted into the conserved TED fold to form a slipknot structure. Further, the B. anthracis TED domain is presented in the context of a full-length sortase-anchored protein structure (BaTIE). This provides insight into the three-dimensional arrangement of TIE proteins, which emerge as very abundant putative adhesins of Gram-positive bacteria.
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Affiliation(s)
- Ona K Miller
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
| | - Mark J Banfield
- John Innes Centre, Department of Biological Chemistry, Norwich Research Park, Norwich, NR4 7UH, United Kingdom
| | - Ulrich Schwarz-Linek
- Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, KY16 9ST, United Kingdom
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13
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Wang Y, Wei Y, Yuan S, Tao H, Dong J, Zhang Z, Tian W, Liu C. Bacillus anthracis S-layer protein BslA binds to extracellular matrix by interacting with laminin. BMC Microbiol 2016; 16:183. [PMID: 27514510 PMCID: PMC4981971 DOI: 10.1186/s12866-016-0802-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 08/04/2016] [Indexed: 01/27/2023] Open
Abstract
Background The Bacillus anthracis S-layer protein, BslA, plays a crucial role in mammalian infection. BslA is required to mediate adherence between host cells and vegetative forms of bacteria and this interaction promotes target organs adherence and blood–brain barrier (BBB) penetration in vivo. This study attempts to identify the potential eukaryotic ligand(s) for B. anthracis BslA protein. Results Biochemical approaches have indicated that the putative host cell ligand(s) for BslA is a surface protein, which is independent of the sugar components for binding to Bs1A. A ligand screening using blot overlays, far Western blots and mass spectrometry analyses revealed that BslA binds to mammalian laminin. ELISA based solid-phase binding assays and surface plasmon resonance assays demonstrated that there were high affinity interactions between BslA(260–652) and laminin. The SPR results also revealed the dissociation constants values of 3.172 × 10−9M for the binding of BslA(260–652) to laminin. Conclusions These data demonstrated that laminin is a ligand for BslA. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0802-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yanchun Wang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China.
| | - Ying Wei
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China.,School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Shengling Yuan
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Haoxia Tao
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Jie Dong
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Zhaoshan Zhang
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China
| | - Wei Tian
- School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, 110016, China
| | - Chunjie Liu
- State Key Laboratory of Pathogens and Biosecurity, Beijing Institute of Biotechnology, Beijng, 100071, China.
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14
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Cyclic di-GMP contributes to adaption and virulence of Bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein. Sci Rep 2016; 6:28807. [PMID: 27381437 PMCID: PMC4933901 DOI: 10.1038/srep28807] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 06/10/2016] [Indexed: 02/06/2023] Open
Abstract
Cyclic di-GMP is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. In Bacillus thuringiensis BMB171, a c-di-GMP riboswitch termed Bc2 RNA resides in the 5'-untranslated region (5'-UTR) of an mRNA that encodes a collagen adhesion protein (Cap). The expression of cap was strongly repressed in parent strain BMB171 because of the presence of Bc2 RNA but was significantly promoted in the Bc2 RNA markerless deletion mutant. Bc2 RNA acts as a genetic "on" switch, which forms an anti-terminator structure to promote cap read-through transcription upon c-di-GMP binding. As a result, cap transcription was de-repressed under high c-di-GMP levels. Therefore, Bc2 RNA regulates cap expression using a repression/de-repression model. Bc2 RNA-regulated Cap was also found to be tightly associated with motility, aggregation, exopolysaccharide secretion, biofilm formation, and virulence of B. thuringiensis BMB171 against its host insect Helicoverpa armigera.
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15
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Wide distribution of virulence genes among Enterococcus faecium and Enterococcus faecalis clinical isolates. ScientificWorldJournal 2014; 2014:623174. [PMID: 25147855 PMCID: PMC4124215 DOI: 10.1155/2014/623174] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/13/2014] [Accepted: 06/19/2014] [Indexed: 12/02/2022] Open
Abstract
Enterococcus, a Gram-positive facultative anaerobic cocci belonging to the lactic acid bacteria of the phylum Firmicutes, is known to be able to resist a wide range of hostile conditions such as different pH levels, high concentration of NaCl (6.5%), and the extended temperatures between 5°C and 65°C. Despite being the third most common nosocomial pathogen, our understanding on its virulence factors is still poorly understood. The current study was aimed to determine the prevalence of different virulence genes in Enterococcus faecalis and Enterococcus faecium. For this purpose, 79 clinical isolates of Malaysian enterococci were evaluated for the presence of virulence genes. pilB, fms8, efaAfm, and sgrA genes are prevalent in all clinical isolates. In conclusion, the pathogenicity of E. faecalis and E. faecium could be associated with different virulence factors and these genes are widely distributed among the enterococcal species.
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16
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Kim SK, Park MK, Kim SH, Oh KG, Jung KH, Hong CH, Yoon JW, Chai YG. Identification of stringent response-related and potential serological proteins released from Bacillus anthracis overexpressing the RelA/SpoT homolog, Rsh Bant. Curr Microbiol 2014; 69:436-44. [PMID: 24838666 DOI: 10.1007/s00284-014-0606-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 03/20/2014] [Indexed: 11/28/2022]
Abstract
RelA and SpoT synthesize ppGpp, a key effector molecule that facilitates the adaptation of bacteria to nutrient starvation and other stresses, known as the stringent response. To investigate the role of Rsh Bant , a putative RelA/SpoT homolog (encoded by BAS4302) in Bacillus anthracis, we examined the alteration of the secretome profiles after the overexpression of a functional His-Rsh Bant protein in the B. anthracis strain Sterne at the stationary growth phase. In the ppGpp-deficient E. coli mutant strain CF1693, overexpression of Rsh Bant restored a ppGpp-dependent growth defect on minimal glucose media. The secretome profiles obtained using a two-dimensional electrophoresis (2-DE) analysis were altered by overexpression of Rsh Bant in B. anthracis. Among the 66 protein spots differentially expressed >1.5-fold, the 29 proteins were abundant for further identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Functional categorization of those proteins implicated their involvement in various biological activities. Taken together, our results imply that overexpression of a functional His-Rsh Bant can lead to the increased levels of intracellular ppGpp in B. anthracis, resulting in the significant changes in its secretome profiling. The stringent response-controlled proteins identified are likely useful as potential targets for serodiagnostic applications.
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Affiliation(s)
- Se Kye Kim
- Department of Molecular and Life Sciences, Hanyang University, 1271, Ansan, 426-791, Gyeonggi-do, Republic of Korea
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17
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Candela T, Balomenou S, Aucher W, Bouriotis V, Simore JP, Fouet A, Boneca IG. N-acetylglucosamine deacetylases modulate the anchoring of the gamma-glutamyl capsule to the cell wall of Bacillus anthracis. Microb Drug Resist 2014; 20:222-30. [PMID: 24833281 DOI: 10.1089/mdr.2014.0063] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Bacillus anthracis has a complex cell wall structure composed of a peptidoglycan (PG) layer to which major structures are anchored such as a neutral polysaccharide, an S-layer, and a poly-γ-D-glutamate (PDGA) capsule. Many of these structures have central roles in the biology of B. anthracis, particularly, in virulence. However, little attention has been devoted to structurally study the PG and how it is modified in the presence of these secondary cell wall components. We present here the fine structure of the PG of the encapsulated RPG1 strain harboring both pXO1 and pXO2 virulence plasmids. We show that B. anthracis has a high degree of cross-linking and its GlcNAc residues are highly modified by N-deacetylation. The PG composition is not dependent on the presence of either LPXTG proteins or the capsule. Using NMR analysis of the PG-PDGA complex, we provide evidence for the anchoring of the PDGA to the glucosamine residues. We show that anchoring of the PDGA capsule is impaired in two PG N-deacetylase mutants, Ba1961 and Ba3679. Thus, these multiple N-deactylase activities would constitute excellent drug targets in B. anthracis by simultaneously affecting its resistance to lysozyme and to phagocytosis impairing B. anthracis survival in the host.
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Affiliation(s)
- Thomas Candela
- 1 Institut Pasteur , Unité Toxines et Pathogénie Bactérienne, Paris, France
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18
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Foster TJ, Geoghegan JA, Ganesh VK, Höök M. Adhesion, invasion and evasion: the many functions of the surface proteins of Staphylococcus aureus. Nat Rev Microbiol 2014; 12:49-62. [PMID: 24336184 DOI: 10.1038/nrmicro3161] [Citation(s) in RCA: 970] [Impact Index Per Article: 97.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Staphylococcus aureus is an important opportunistic pathogen and persistently colonizes about 20% of the human population. Its surface is 'decorated' with proteins that are covalently anchored to the cell wall peptidoglycan. Structural and functional analysis has identified four distinct classes of surface proteins, of which microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) are the largest class. These surface proteins have numerous functions, including adhesion to and invasion of host cells and tissues, evasion of immune responses and biofilm formation. Thus, cell wall-anchored proteins are essential virulence factors for the survival of S. aureus in the commensal state and during invasive infections, and targeting them with vaccines could combat S. aureus infections.
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Affiliation(s)
- Timothy J Foster
- Microbiology Department, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
| | - Joan A Geoghegan
- Microbiology Department, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
| | - Vannakambadi K Ganesh
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030, USA
| | - Magnus Höök
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030, USA
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19
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Adhesive properties of Clostridium perfringens to extracellular matrix proteins collagens and fibronectin. Anaerobe 2014; 25:67-71. [DOI: 10.1016/j.anaerobe.2013.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 10/17/2013] [Accepted: 11/06/2013] [Indexed: 11/20/2022]
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20
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Kang M, Ko YP, Liang X, Ross CL, Liu Q, Murray BE, Höök M. Collagen-binding microbial surface components recognizing adhesive matrix molecule (MSCRAMM) of Gram-positive bacteria inhibit complement activation via the classical pathway. J Biol Chem 2013; 288:20520-31. [PMID: 23720782 DOI: 10.1074/jbc.m113.454462] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Members of a family of collagen-binding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) from Gram-positive bacteria are established virulence factors in several infectious diseases models. Here, we report that these adhesins also can bind C1q and act as inhibitors of the classical complement pathway. Molecular analyses of Cna from Staphylococcus aureus suggested that this prototype MSCRAMM bound to the collagenous domain of C1q and interfered with the interactions of C1r with C1q. As a result, C1r2C1s2 was displaced from C1q, and the C1 complex was deactivated. This novel function of the Cna-like MSCRAMMs represents a potential immune evasion strategy that could be used by numerous Gram-positive pathogens.
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Affiliation(s)
- Mingsong Kang
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas 77030, USA
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21
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Abstract
Molecular mimicry of host proteins is a common strategy adopted by bacterial pathogens to interfere with and exploit host processes. Despite the availability of pathogen genomes, few studies have attempted to predict virulence-associated mimicry relationships directly from genomic sequences. Here, we analyzed the proteomes of 62 pathogenic and 66 non-pathogenic bacterial species, and screened for the top pathogen-specific or pathogen-enriched sequence similarities to human proteins. The screen identified approximately 100 potential mimicry relationships including well-characterized examples among the top-scoring hits (e.g., RalF, internalin, yopH, and others), with about 1/3 of predicted relationships supported by existing literature. Examination of homology to virulence factors, statistically enriched functions, and comparison with literature indicated that the detected mimics target key host structures (e.g., extracellular matrix, ECM) and pathways (e.g., cell adhesion, lipid metabolism, and immune signaling). The top-scoring and most widespread mimicry pattern detected among pathogens consisted of elevated sequence similarities to ECM proteins including collagens and leucine-rich repeat proteins. Unexpectedly, analysis of the pathogen counterparts of these proteins revealed that they have evolved independently in different species of bacterial pathogens from separate repeat amplifications. Thus, our analysis provides evidence for two classes of mimics: complex proteins such as enzymes that have been acquired by eukaryote-to-pathogen horizontal transfer, and simpler repeat proteins that have independently evolved to mimic the host ECM. Ultimately, computational detection of pathogen-specific and pathogen-enriched similarities to host proteins provides insights into potentially novel mimicry-mediated virulence mechanisms of pathogenic bacteria.
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Affiliation(s)
- Andrew C Doxey
- Department of Biology, University of Waterloo, Waterloo, ON, Canada.
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22
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Ross CL, Liang X, Liu Q, Murray BE, Höök M, Ganesh VK. Targeted protein engineering provides insights into binding mechanism and affinities of bacterial collagen adhesins. J Biol Chem 2012; 287:34856-65. [PMID: 22865854 DOI: 10.1074/jbc.m112.371054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The collagen-binding bacterial proteins, Ace and Cna, are well characterized on the biochemical and structural level. Despite overall structural similarity, recombinant forms of the Ace and Cna ligand-binding domains exhibit significantly different affinities and binding kinetics for collagen type I (CI) in vitro. In this study, we sought to understand, in submolecular detail, the bases for these differences. Using a structure-based approach, we engineered Cna and Ace variants by altering specific structural elements within the ligand-binding domains. Surface plasmon resonance-based binding analysis demonstrated that mutations that are predicted to alter the orientation of the Ace and Cna N(1) and N(2) subdomains significantly affect the interaction between the MSCRAMM (microbial surface components recognizing adhesive matrix molecule) and CI in vitro, including affinity, association/dissociation rates and binding ratio. Moreover, we utilized this information to engineer an Ace variant with an 11,000-fold higher CI affinity than the parent protein. Finally, we noted that several engineered proteins that exhibited a weak interaction with CI recognized more sites on CI, suggesting an inverse correlation between affinity and specificity.
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Affiliation(s)
- Caná L Ross
- Center for Inflammatory and Infectious Disease, Institute for Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas 77030, USA
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23
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Singh B, Fleury C, Jalalvand F, Riesbeck K. Human pathogens utilize host extracellular matrix proteins laminin and collagen for adhesion and invasion of the host. FEMS Microbiol Rev 2012; 36:1122-80. [PMID: 22537156 DOI: 10.1111/j.1574-6976.2012.00340.x] [Citation(s) in RCA: 210] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2011] [Revised: 02/08/2012] [Accepted: 03/29/2012] [Indexed: 01/11/2023] Open
Abstract
Laminin (Ln) and collagen are multifunctional glycoproteins that play an important role in cellular morphogenesis, cell signalling, tissue repair and cell migration. These proteins are ubiquitously present in tissues as a part of the basement membrane (BM), constitute a protective layer around blood capillaries and are included in the extracellular matrix (ECM). As a component of BMs, both Lns and collagen(s), thus function as major mechanical containment molecules that protect tissues from pathogens. Invasive pathogens breach the basal lamina and degrade ECM proteins of interstitial spaces and connective tissues using various ECM-degrading proteases or surface-bound plasminogen and matrix metalloproteinases recruited from the host. Most pathogens associated with the respiratory, gastrointestinal, or urogenital tracts, as well as with the central nervous system or the skin, have the capacity to bind and degrade Lns and collagen(s) in order to adhere to and invade host tissues. In this review, we focus on the adaptability of various pathogens to utilize these ECM proteins as enhancers for adhesion to host tissues or as a targets for degradation in order to breach the cellular barriers. The major pathogens discussed are Streptococcus, Staphylococcus, Pseudomonas, Salmonella, Yersinia, Treponema, Mycobacterium, Clostridium, Listeria, Porphyromonas and Haemophilus; Candida, Aspergillus, Pneumocystis, Cryptococcus and Coccidioides; Acanthamoeba, Trypanosoma and Trichomonas; retrovirus and papilloma virus.
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Affiliation(s)
- Birendra Singh
- Medical Microbiology, Department of Laboratory Medicine Malmö, Skåne University Hospital, Lund University, Malmö, Sweden
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Thomas RJ. Receptor mimicry as novel therapeutic treatment for biothreat agents. Bioeng Bugs 2011; 1:17-30. [PMID: 21327124 DOI: 10.4161/bbug.1.1.10049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/10/2009] [Accepted: 09/11/2009] [Indexed: 12/20/2022] Open
Abstract
The specter of intentional release of pathogenic microbes and their toxins is a real threat. This article reviews the literature on adhesins of biothreat agents, their interactions with oligosaccharides and the potential for anti-adhesion compounds as an alternative to conventional therapeutics. The minimal binding structure of ricin has been well characterised and offers the best candidate for successful anti-adhesion therapy based on the Galβ1-4GlcNAc structure. The botulinum toxin serotypes A-F bind to a low number of gangliosides (GT1b, GQ1b, GD1a and GD1b) hence it should be possible to determine the minimal structure for binding. The minimal disaccharide sequence of GalNAcβ1-4Gal found in the gangliosides asialo-GM1 and asialo-GM2 is required for adhesion for many respiratory pathogens. Although a number of adhesins have been identified in bacterial biothreat agents such as Yersinia pestis, Bacillus anthracis, Francisella tularensis, Brucella species and Burkholderia pseudomallei, specific information regarding their in vivo expression during pneumonic infection is lacking. Limited oligosaccharide inhibition studies indicate the potential of GalNAcβ1-4Gal, GalNAcβ-3Gal and the hydrophobic compound, para-nitrophenol as starting points for the rational design of generic anti-adhesion compounds. A cocktail of multivalent oligosaccharides based on the minimal binding structures of identified adhesins would offer the best candidates for anti-adhesion therapy.
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Crystallography of gram-positive bacterial adhesins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 715:175-95. [PMID: 21557064 DOI: 10.1007/978-94-007-0940-9_11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Both Gram-negative and Gram-positive pathogens display a multitude of proteins and protein assemblies (pili or fimbriae) on their cell surfaces, which are often used for adherence and initiate colonization and pathogenesis. Adhesive proteins known as MSCRAMMs (microbial surface components recognizing adhesive matrix molecules), anchored by a specific enzyme called sortase in Gram-positive bacteria, target the host's extracellular matrix proteins (ECM) like collagen, fibrinogen and fibronectin. In the past decade, structural analysis by X-ray crystallography has enhanced our understanding of the interactions between MSCRAMMs and the host ECM by revealing several novel structural features that dictate surface protein assembly and the mode of their adhesion to host tissue. The latest focus is on the recently discovered Gram-positive bacterial pili, assembly of which is assisted by yet another specific sortase. Novel features like inter- and intra-molecular isopeptide bonds that facilitate the stability of the pilins, and intra-molecular donor strand complementation to stabilize the adhesin-target interactions are specific to Gram-positive bacteria. This chapter describes and discusses the common structural details between surface proteins and pilins of Gram-positive bacteria and biological implications emanating from these structures.
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26
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Singh KV, Nallapareddy SR, Sillanpää J, Murray BE. Importance of the collagen adhesin ace in pathogenesis and protection against Enterococcus faecalis experimental endocarditis. PLoS Pathog 2010; 6:e1000716. [PMID: 20072611 PMCID: PMC2798748 DOI: 10.1371/journal.ppat.1000716] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 12/03/2009] [Indexed: 11/19/2022] Open
Abstract
Ace is an adhesin to collagen from Enterococcus faecalis expressed conditionally after growth in serum or in the presence of collagen. Here, we generated an ace deletion mutant and showed that it was significantly attenuated versus wild-type OG1RF in a mixed infection rat endocarditis model (P<0.0001), while no differences were observed in a peritonitis model. Complemented OG1RFΔace (pAT392::ace) enhanced early (4 h) heart valve colonization versus OG1RFΔace (pAT392) (P = 0.0418), suggesting that Ace expression is important for early attachment. By flow cytometry using specific anti-recombinant Ace (rAce) immunoglobulins (Igs), we showed in vivo expression of Ace by OG1RF cells obtained directly from infected vegetations, consistent with our previous finding of anti-Ace antibodies in E. faecalis endocarditis patient sera. Finally, rats actively immunized against rAce were less susceptible to infection by OG1RF than non-immunized (P = 0.0004) or sham-immunized (P = 0.0475) by CFU counts. Similarly, animals given specific anti-rAce Igs were less likely to develop E. faecalis endocarditis (P = 0.0001) and showed fewer CFU in vegetations (P = 0.0146). In conclusion, we have shown for the first time that Ace is involved in pathogenesis of, and is useful for protection against, E. faecalis experimental endocarditis. Enterococcus faecalis was recognized as a common cause of infective endocarditis (IE) by the early 1900s. It is still third in community-onset IE, but is the second most common cause of hospital-associated IE. Complications due to E. faecalis IE include congestive heart failure, septic emboli and death and current management involves a combination of antimicrobials, often with surgery. Emergence of antimicrobial resistance has created the need for alternative strategies (such as immunoprophylaxis) that target in vivo expressed virulence-associated surface proteins. One such E. faecalis protein is Ace, which is antigenic during human IE and mediates attachment of E. faecalis cells to host extracellular matrix proteins collagen and laminin. Using a rat model, we now show that ace contributes to E. faecalis IE pathogenesis and demonstrate that Ace is expressed at high levels during IE even though produced at low levels under laboratory conditions; both active and passive immunization based on the collagen-binding domain of Ace conferred significant protection against IE. These observations, along with data that human antibodies against Ace inhibit collagen adherence of E. faecalis, indicate that Ace is an important virulence-associated factor and a promising target for prophylactic and possibly therapeutic strategies against E. faecalis IE.
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Affiliation(s)
- Kavindra V. Singh
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, Texas, United States of America
- Center for the Study of Emerging and Re-emerging Pathogens; University of Texas Medical School, Houston, Texas, United States of America
| | - Sreedhar R. Nallapareddy
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, Texas, United States of America
- Center for the Study of Emerging and Re-emerging Pathogens; University of Texas Medical School, Houston, Texas, United States of America
| | - Jouko Sillanpää
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, Texas, United States of America
- Center for the Study of Emerging and Re-emerging Pathogens; University of Texas Medical School, Houston, Texas, United States of America
| | - Barbara E. Murray
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, Texas, United States of America
- Center for the Study of Emerging and Re-emerging Pathogens; University of Texas Medical School, Houston, Texas, United States of America
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas, United States of America
- * E-mail:
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Fouet A. The surface of Bacillus anthracis. Mol Aspects Med 2009; 30:374-85. [PMID: 19607856 DOI: 10.1016/j.mam.2009.07.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 07/08/2009] [Indexed: 11/25/2022]
Abstract
Bacillus anthracis is a Gram positive organism possessing a complex parietal structure. An S-layer, a bi-dimensional crystalline layer, and a peptidic capsule surround the thick peptidoglycan of bacilli harvested during infection. A review of the current literature indicates that elements from each of these three structures, as well as membrane components, have been studied. So-called cell-wall secondary polymers, be they attached to the cell-wall or to the membrane play important functions, either per se or because they permit the anchoring of proteins. Some surface proteins, whichever compartment they are attached to, play, as had been hypothesized, key roles in virulence. Others, of yet unknown function, are nevertheless expressed in vivo. This review will focus on well-studied polymers or proteins and indicate, when appropriate, the mechanisms by which they are targeted to their respective locations.
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Affiliation(s)
- Agnès Fouet
- Institut Pasteur, Unité Toxines et Pathogénie Bactérienne, CNRS, URA2172, F-75015 Paris, France.
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Sillanpää J, Nallapareddy SR, Prakash VP, Qin X, Hook M, Weinstock GM, Murray BE. Identification and phenotypic characterization of a second collagen adhesin, Scm, and genome-based identification and analysis of 13 other predicted MSCRAMMs, including four distinct pilus loci, in Enterococcus faecium. MICROBIOLOGY (READING, ENGLAND) 2008; 154:3199-3211. [PMID: 18832325 PMCID: PMC2677164 DOI: 10.1099/mic.0.2008/017319-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Attention has recently been drawn to Enterococcus faecium because of an increasing number of nosocomial infections caused by this species and its resistance to multiple antibacterial agents. However, relatively little is known about the pathogenic determinants of this organism. We have previously identified a cell-wall-anchored collagen adhesin, Acm, produced by some isolates of E. faecium, and a secreted antigen, SagA, exhibiting broad-spectrum binding to extracellular matrix proteins. Here, we analysed the draft genome of strain TX0016 for potential microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). Genome-based bioinformatics identified 22 predicted cell-wall-anchored E. faecium surface proteins (Fms), of which 15 (including Acm) had characteristics typical of MSCRAMMs, including predicted folding into a modular architecture with multiple immunoglobulin-like domains. Functional characterization of one [Fms10; redesignated second collagen adhesin of E. faecium (Scm)] revealed that recombinant Scm(65) (A- and B-domains) and Scm(36) (A-domain) bound to collagen type V efficiently in a concentration-dependent manner, bound considerably less to collagen type I and fibrinogen, and differed from Acm in their binding specificities to collagen types IV and V. Results from far-UV circular dichroism measurements of recombinant Scm(36) and of Acm(37) indicated that these proteins were rich in beta-sheets, supporting our folding predictions. Whole-cell ELISA and FACS analyses unambiguously demonstrated surface expression of Scm in most E. faecium isolates. Strikingly, 11 of the 15 predicted MSCRAMMs clustered in four loci, each with a class C sortase gene; nine of these showed similarity to Enterococcus faecalis Ebp pilus subunits and also contained motifs essential for pilus assembly. Antibodies against one of the predicted major pilus proteins, Fms9 (redesignated EbpC(fm)), detected a 'ladder' pattern of high-molecular-mass protein bands in a Western blot analysis of cell surface extracts from E. faecium, suggesting that EbpC(fm) is polymerized into a pilus structure. Further analysis of the transcripts of the corresponding gene cluster indicated that fms1 (ebpA(fm)), fms5 (ebpB(fm)) and ebpC(fm) are co-transcribed, a result consistent with those for pilus-encoding gene clusters of other Gram-positive bacteria. All 15 genes occurred frequently in 30 clinically derived diverse E. faecium isolates tested. The common occurrence of MSCRAMM- and pilus-encoding genes and the presence of a second collagen-binding protein may have important implications for our understanding of this emerging pathogen.
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Affiliation(s)
- Jouko Sillanpää
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA
- Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA
| | - Sreedhar R. Nallapareddy
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA
- Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA
| | - Vittal P. Prakash
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA
- Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA
| | - Xiang Qin
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Magnus Hook
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - George M. Weinstock
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, USA
| | - Barbara E. Murray
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical School, Houston, TX, USA
- Center for the Study of Emerging and Re-emerging Pathogens, University of Texas Medical School, Houston, TX, USA
- Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, TX, USA
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30
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Passalacqua KD, Bergman NH. Bacillus anthracis: interactions with the host and establishment of inhalational anthrax. Future Microbiol 2007; 1:397-415. [PMID: 17661631 DOI: 10.2217/17460913.1.4.397] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Due to its potential as a bioweapon, Bacillus anthracis has received a great deal of attention in recent years, and a significant effort has been devoted to understanding how this organism causes anthrax. There has been a particular focus on the inhalational form of the disease, and studies over the past several years have painted an increasingly complex picture of how B. anthracis enters the mammalian host, survives the host's defense mechanisms, disseminates throughout the body and causes death. This article reviews recent advances in these areas, with a focus on how the bacterium interacts with its host in establishing infection and causing anthrax.
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Affiliation(s)
- Karla D Passalacqua
- University of Michigan Medical School, Department of Microbiology & Immunology, Ann Arbor, MI 48109, USA.
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31
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Pietrocola G, Valtulina V, Rindi S, Jost BH, Speziale P. Functional and structural properties of CbpA, a collagen-binding protein from Arcanobacterium pyogenes. MICROBIOLOGY-SGM 2007; 153:3380-3389. [PMID: 17906137 DOI: 10.1099/mic.0.2007/009100-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Arcanobacterium pyogenes, an opportunistic pathogen of economically important food animals, is the causative agent of liver abscesses in feedlot cattle, osteomyelitis in turkeys, and pneumonia and arthritis in pigs. Previous studies identified the first A. pyogenes adhesin, CbpA, a protein located on the bacterial surface which has the ability to bind collagen and promotes adhesion to the host cells. The protein has an N-terminal ligand-binding region (region A) and a C-terminal repetitive domain (region B). In this study we found that CbpA bound to almost all the collagen types tested but not to other proteins, and it displayed a propensity to interact with several collagenous peptides derived by CNBr cleavage of type I and II collagens. The K(D) values of CbpA for type I and II collagens and collagen peptides determined by solid-phase binding assay and intrinsic tryptophan fluorescence were in the range of 1-15 nM. It was also found that CbpA and its A region bound fibronectin, and that collagen and fibronectin interacted with distinct subsites. Anti-CbpA antibodies were effective at inhibiting both binding of isolated CbpA and bacterial adhesion to immobilized collagen, suggesting that CbpA is a functional collagen-binding adhesin. Analysis of the immunological cross-reactivity of CbpA with antibodies against other bacterial collagen-binding proteins indicated that CbpA is immunologically related to ACE from Enterococcus faecalis but not to CNA from Staphylococcus aureus or Acm from Enterococcus faecium. Far-UV and near-UV circular dichroism spectra showed that full-length CbpA and its region A are mainly composed of beta-sheet with only a minor alpha-helical component and that both the proteins have a well-defined tertiary structure.
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Affiliation(s)
- Giampiero Pietrocola
- University of Pavia, Department of Biochemistry, Viale Taramelli 3/B, 27100 Pavia, Italy
| | - Viviana Valtulina
- University of Pavia, Department of Biochemistry, Viale Taramelli 3/B, 27100 Pavia, Italy
| | - Simonetta Rindi
- University of Pavia, Department of Biochemistry, Viale Taramelli 3/B, 27100 Pavia, Italy
| | - B Helen Jost
- Department of Veterinary Science and Microbiology, The University of Arizona, Tucson, AZ 85721, USA
| | - Pietro Speziale
- University of Pavia, Department of Biochemistry, Viale Taramelli 3/B, 27100 Pavia, Italy
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Hall AE, Gorovits EL, Syribeys PJ, Domanski PJ, Ames BR, Chang CY, Vernachio JH, Patti JM, Hutchins JT. Monoclonal antibodies recognizing the Enterococcus faecalis collagen-binding MSCRAMM Ace: conditional expression and binding analysis. Microb Pathog 2007; 43:55-66. [PMID: 17521860 DOI: 10.1016/j.micpath.2007.03.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Revised: 03/23/2007] [Accepted: 03/25/2007] [Indexed: 10/23/2022]
Abstract
Enterococci are opportunistic pathogens known to cause numerous clinical infections and complications in humans. Adhesin-mediated binding to extracellular matrix (ECM) proteins of the host is thought to be a crucial step in the pathogenesis of these bacterial infections. Adhesin of collagen from Enterococcus faecalis (Ace) is a cell-wall anchored protein of E. faecalis that has been shown to be important for bacterial binding to the ECM. In this report, we characterize the conditions for Ace expression and demonstrate Ace binding to mammalian epithelial and endothelial cells as well as to collagens found in the ECM. To further characterize Ace expression and function, we report the generation of a panel of monoclonal antibodies (mAbs) directed against this important E. faecalis virulence factor. Through the use of multiple in vitro assays, surface plasmon resonance and flow cytometry, we have characterized this panel of mAbs which may prove to be not only beneficial in studies that address the precise biological role of adhesion of E. faecalis, but may also serve as beneficial therapeutic agents against E. faecalis infections.
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Affiliation(s)
- Andrea E Hall
- Inhibitex, Inc., 9005 Westside Parkway, Alpharetta, GA 30004, USA
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Abstract
Dormant spores of Bacillus anthracis germinate during host infection and their vegetative growth and dissemination precipitate anthrax disease. Upon host death, bacilli engage a developmental programme to generate infectious spores within carcasses. Hallmark of sporulation in Bacillus spp. is the formation of an asymmetric division septum between mother cell and forespore compartments. We show here that sortase C (SrtC) cleaves the LPNTA sorting signal of BasH and BasI, thereby targeting both polypeptides to the cell wall of sporulating bacilli. Sortase substrates are initially produced in different cell compartments and at different developmental stages but penultimately decorate the envelope of the maturing spore. srtC mutants appear to display no defect during the initial stages of infection and precipitate lethal anthrax disease in guinea pigs at a similar rate as wild-type B. anthracis strain Ames. Unlike wild-type bacilli, srtC mutants do not readily form spores in guinea pig tissue or sheep blood unless their vegetative forms are exposed to air.
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Affiliation(s)
- Luciano A Marraffini
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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Itoi Y, Horinaka M, Tsujimoto Y, Matsui H, Watanabe K. Characteristic features in the structure and collagen-binding ability of a thermophilic collagenolytic protease from the thermophile Geobacillus collagenovorans MO-1. J Bacteriol 2006; 188:6572-9. [PMID: 16952949 PMCID: PMC1595469 DOI: 10.1128/jb.00767-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A collagen-degrading thermophile, Geobacillus collagenovorans MO-1, extracellularly produces a collagenolytic protease with a large molecular mass. Complete nucleotide sequencing of this gene after gene cloning revealed that the collagenolytic protease is a member of the subtilisin family of serine proteases and consists of a signal sequence for secretion, a prosequence for maturation, a catalytic region, 14 direct repeats of 20 amino acids at the C terminus, and a region with unknown function intervening between the catalytic region and the numerous repeats. Since the unusual repeats are most likely to be cleaved in the secreted form of the enzyme, the intervening region was investigated to determine whether it participates in collagen binding to facilitate collagen degradation. It was found that the mature collagenolytic protease containing the intervening region at the C terminus bound collagen but not the other insoluble proteins, elastin and keratin. Furthermore, the intervening region fused with glutathione S-transferase showed a collagen-binding ability comparable to that of the mature collagenolytic protease. The collagen-binding ability was finally attributed to two-thirds of the intervening region which is rich in beta-strands and is approximately 35 kDa in molecular mass. In the collagenolytic protease from strain MO-1, hydrogen bonds most likely predominate over the hydrophobic interaction for collagen binding, since a higher concentration of NaCl released collagen from the enzyme surface but a nonionic detergent could not. To the best of our knowledge, this is the first report of a thermophilic collagenolytic protease containing the collagen-binding segment.
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Affiliation(s)
- Yuichi Itoi
- Department of Applied Biochemistry, Kyoto Prefectural University, Shimogamo, Sakyo, Kyoto 606-8522, Japan
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35
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Gat O, Grosfeld H, Ariel N, Inbar I, Zaide G, Broder Y, Zvi A, Chitlaru T, Altboum Z, Stein D, Cohen S, Shafferman A. Search for Bacillus anthracis potential vaccine candidates by a functional genomic-serologic screen. Infect Immun 2006; 74:3987-4001. [PMID: 16790772 PMCID: PMC1489694 DOI: 10.1128/iai.00174-06] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 03/17/2006] [Accepted: 03/30/2006] [Indexed: 12/28/2022] Open
Abstract
Bacillus anthracis proteins that possess antigenic properties and are able to evoke an immune response were identified by a reductive genomic-serologic screen of a set of in silico-preselected open reading frames (ORFs). The screen included in vitro expression of the selected ORFs by coupled transcription and translation of linear PCR-generated DNA fragments, followed by immunoprecipitation with antisera from B. anthracis-infected animals. Of the 197 selected ORFs, 161 were chromosomal and 36 were on plasmids pXO1 and pXO2, and 138 of the 197 ORFs had putative functional annotations (known ORFs) and 59 had no assigned functions (unknown ORFs). A total of 129 of the known ORFs (93%) could be expressed, whereas only 38 (64%) of the unknown ORFs were successfully expressed. All 167 expressed polypeptides were subjected to immunoprecipitation with the anti-B. anthracis antisera, which revealed 52 seroreactive immunogens, only 1 of which was encoded by an unknown ORF. The high percentage of seroreactive ORFs among the functionally annotated ORFs (37%; 51/129) attests to the predictive value of the bioinformatic strategy used for vaccine candidate selection. Furthermore, the experimental findings suggest that surface-anchored proteins and adhesins or transporters, such as cell wall hydrolases, proteins involved in iron acquisition, and amino acid and oligopeptide transporters, have great potential to be immunogenic. Most of the seroreactive ORFs that were tested as DNA vaccines indeed appeared to induce a humoral response in mice. We list more than 30 novel B. anthracis immunoreactive virulence-related proteins which could be useful in diagnosis, pathogenesis studies, and future anthrax vaccine development.
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Affiliation(s)
- Orit Gat
- Israel Institute for Biological Research, P.O. Box 19, Ness Ziona 74100, Israel.
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Chitlaru T, Gat O, Gozlan Y, Ariel N, Shafferman A. Differential proteomic analysis of the Bacillus anthracis secretome: distinct plasmid and chromosome CO2-dependent cross talk mechanisms modulate extracellular proteolytic activities. J Bacteriol 2006; 188:3551-71. [PMID: 16672610 PMCID: PMC1482852 DOI: 10.1128/jb.188.10.3551-3571.2006] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 02/19/2006] [Indexed: 12/17/2022] Open
Abstract
The secretomes of a virulent Bacillus anthracis strain and of avirulent strains (cured of the virulence plasmids pXO1 and pXO2), cultured in rich and minimal media, were studied by a comparative proteomic approach. More than 400 protein spots, representing the products of 64 genes, were identified, and a unique pattern of protein relative abundance with respect to the presence of the virulence plasmids was revealed. In minimal medium under high CO(2) tension, conditions considered to simulate those encountered in the host, the presence of the plasmids leads to enhanced expression of 12 chromosome-carried genes (10 of which could not be detected in the absence of the plasmids) in addition to expression of 5 pXO1-encoded proteins. Furthermore, under these conditions, the presence of the pXO1 and pXO2 plasmids leads to the repression of 14 chromosomal genes. On the other hand, in minimal aerobic medium not supplemented with CO(2), the virulent and avirulent B. anthracis strains manifest very similar protein signatures, and most strikingly, two proteins (the metalloproteases InhA1 and NprB, orthologs of gene products attributed to the Bacillus cereus group PlcR regulon) represent over 90% of the total secretome. Interestingly, of the 64 identified gene products, at least 31 harbor features characteristic of virulence determinants (such as toxins, proteases, nucleotidases, sulfatases, transporters, and detoxification factors), 22 of which are differentially regulated in a plasmid-dependent manner. The nature and the expression patterns of proteins in the various secretomes suggest that distinct CO(2)-responsive chromosome- and plasmid-encoded regulatory factors modulate the secretion of potential novel virulence factors, most of which are associated with extracellular proteolytic activities.
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Affiliation(s)
- Theodor Chitlaru
- Department of Biochemistry and Molecular Genetics, Israel Institute for Biological Research, Ness-Ziona
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37
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Marraffini LA, Dedent AC, Schneewind O. Sortases and the art of anchoring proteins to the envelopes of gram-positive bacteria. Microbiol Mol Biol Rev 2006; 70:192-221. [PMID: 16524923 PMCID: PMC1393253 DOI: 10.1128/mmbr.70.1.192-221.2006] [Citation(s) in RCA: 509] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The cell wall envelopes of gram-positive bacteria represent a surface organelle that not only functions as a cytoskeletal element but also promotes interactions between bacteria and their environment. Cell wall peptidoglycan is covalently and noncovalently decorated with teichoic acids, polysaccharides, and proteins. The sum of these molecular decorations provides bacterial envelopes with species- and strain-specific properties that are ultimately responsible for bacterial virulence, interactions with host immune systems, and the development of disease symptoms or successful outcomes of infections. Surface proteins typically carry two topogenic sequences, i.e., N-terminal signal peptides and C-terminal sorting signals. Sortases catalyze a transpeptidation reaction by first cleaving a surface protein substrate at the cell wall sorting signal. The resulting acyl enzyme intermediates between sortases and their substrates are then resolved by the nucleophilic attack of amino groups, typically provided by the cell wall cross bridges of peptidoglycan precursors. The surface protein linked to peptidoglycan is then incorporated into the envelope and displayed on the microbial surface. This review focuses on the mechanisms of surface protein anchoring to the cell wall envelope by sortases and the role that these enzymes play in bacterial physiology and pathogenesis.
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Affiliation(s)
- Luciano A Marraffini
- Department of Microbiology, Genetics and Cell Biology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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38
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Zong Y, Xu Y, Liang X, Keene DR, Höök A, Gurusiddappa S, Höök M, Narayana SVL. A 'Collagen Hug' model for Staphylococcus aureus CNA binding to collagen. EMBO J 2005; 24:4224-36. [PMID: 16362049 PMCID: PMC1356329 DOI: 10.1038/sj.emboj.7600888] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Accepted: 11/04/2005] [Indexed: 11/09/2022] Open
Abstract
The structural basis for the association of eukaryotic and prokaryotic protein receptors and their triple-helical collagen ligand remains poorly understood. Here, we present the crystal structures of a high affinity subsegment of the Staphylococcus aureus collagen-binding CNA as an apo-protein and in complex with a synthetic collagen-like triple helical peptide. The apo-protein structure is composed of two subdomains (N1 and N2), each adopting a variant IgG-fold, and a long linker that connects N1 and N2. The structure is stabilized by hydrophobic inter-domain interactions and by the N2 C-terminal extension that complements a beta-sheet on N1. In the ligand complex, the collagen-like peptide penetrates through a spherical hole formed by the two subdomains and the N1-N2 linker. Based on these two structures we propose a dynamic, multistep binding model, called the 'Collagen Hug' that is uniquely designed to allow multidomain collagen binding proteins to bind their extended rope-like ligand.
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Affiliation(s)
- Yinong Zong
- School of Optometry and Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Yi Xu
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Xiaowen Liang
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | | | - Agneta Höök
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Shivasankarappa Gurusiddappa
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
| | - Magnus Höök
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, Houston, TX, USA
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University Health Science Center, 2121 W. Holcombe Blvd, Houston, TX 77030-3303, USA. Tel.: +1 713 677 7552; Fax: +1 713 677 7576; E-mail:
| | - Sthanam V L Narayana
- School of Optometry and Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, AL, USA
- Center for Biophysical Sciences and Engineering, School of Optometry, University of Alabama at Birmingham, 1025 18th Street South, Birmingham, AL 35294, USA. Tel.: +1 205 934 0119; Fax: +1 205 975 0538; E-mail:
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39
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Kudva IT, Griffin RW, Garren JM, Calderwood SB, John M. Identification of a protein subset of the anthrax spore immunome in humans immunized with the anthrax vaccine adsorbed preparation. Infect Immun 2005; 73:5685-96. [PMID: 16113286 PMCID: PMC1231109 DOI: 10.1128/iai.73.9.5685-5696.2005] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We identified spore targets of Anthrax Vaccine Adsorbed (AVA)-induced immunity in humans by screening recombinant clones of a previously generated, limited genomic Bacillus anthracis Sterne (pXO1(+), pXO2(-)) expression library of putative spore surface (spore-associated [SA]) proteins with pooled sera from human adults immunized with AVA (immune sera), the anthrax vaccine currently approved for use by humans in the United States. We identified 69 clones that reacted specifically with pooled immune sera but not with pooled sera obtained from the same individuals prior to immunization. Positive clones expressed proteins previously identified as localized on the anthrax spore surface, proteins highly expressed during spore germination, orthologs of proteins of diverse pathogens under investigation as drug targets, and orthologs of proteins contributing to the virulence of both gram-positive and gram-negative pathogens. Among the reactive clones identified by this immunological screen was one expressing a 15.2-kDa hypothetical protein encoded by a gene with no significant homology to sequences contained in databases. Further studies are required to define the subset of SA proteins identified in this study that contribute to the virulence of this pathogen. We hypothesize that optimal delivery of a subset of SA proteins identified by such studies to the immune system in combination with protective antigen (PA), the principal immunogen in AVA, might facilitate the development of defined, nonreactogenic, more-efficacious PA-based anthrax vaccines. Future studies might also facilitate the identification of SA proteins with potential to serve as targets for drug design, spore inactivation, or spore detection strategies.
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Affiliation(s)
- Indira T Kudva
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
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40
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Abstract
We examined the effect of mutation of two sortase genes of Bacillus anthracis, srtA and srtB, on the ability of the bacterium to grow in J774A.1 cells, a mouse macrophage-like cell line. While disruption of either srtA or srtB had no effect on the ability of the bacteria to grow in rich culture media, mutations in each of these genes dramatically attenuated growth of the bacterium in J774A.1 cells. Complementation of the mutation restored the ability of bacteria to grow in the cells. Since the initial events in inhalation anthrax are believed to be uptake of B. anthracis spores by alveolar macrophages followed by germination of the spores and growth of the bacteria within the macrophages, these results suggest that two sortases of B. anthracis may be critical in the early stages of inhalation anthrax.
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Affiliation(s)
- Steven D Zink
- CBER, FDA HFM-434, 8800 Rockville Pike, Bethesda, MD 20892, USA
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Gaspar AH, Marraffini LA, Glass EM, Debord KL, Ton-That H, Schneewind O. Bacillus anthracis sortase A (SrtA) anchors LPXTG motif-containing surface proteins to the cell wall envelope. J Bacteriol 2005; 187:4646-55. [PMID: 15968076 PMCID: PMC1151759 DOI: 10.1128/jb.187.13.4646-4655.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cell wall-anchored surface proteins of gram-positive pathogens play important roles during the establishment of many infectious diseases, but the contributions of surface proteins to the pathogenesis of anthrax have not yet been revealed. Cell wall anchoring in Staphylococcus aureus occurs by a transpeptidation mechanism requiring surface proteins with C-terminal sorting signals as well as sortase enzymes. The genome sequence of Bacillus anthracis encodes three sortase genes and eleven surface proteins with different types of cell wall sorting signals. Purified B. anthracis sortase A cleaved peptides encompassing LPXTG motif-type sorting signals between the threonine (T) and the glycine (G) residues in vitro. Sortase A activity could be inhibited by thiol-reactive reagents, similar to staphylococcal sortases. B. anthracis parent strain Sterne 34F(2), but not variants lacking the srtA gene, anchored the collagen-binding MSCRAMM (microbial surface components recognizing adhesive matrix molecules) BasC (BA5258/BAS4884) to the bacterial cell wall. These results suggest that B. anthracis SrtA anchors surface proteins bearing LPXTG motif sorting signals to the cell wall envelope of vegetative bacilli.
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Affiliation(s)
- Andrew H Gaspar
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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Abstract
The year 2004 represents a milestone for the biosensor research community: in this year, over 1000 articles were published describing experiments performed using commercially available systems. The 1038 papers we found represent an approximately 10% increase over the past year and demonstrate that the implementation of biosensors continues to expand at a healthy pace. We evaluated the data presented in each paper and compiled a 'top 10' list. These 10 articles, which we recommend every biosensor user reads, describe well-performed kinetic, equilibrium and qualitative/screening studies, provide comparisons between binding parameters obtained from different biosensor users, as well as from biosensor- and solution-based interaction analyses, and summarize the cutting-edge applications of the technology. We also re-iterate some of the experimental pitfalls that lead to sub-optimal data and over-interpreted results. We are hopeful that the biosensor community, by applying the hints we outline, will obtain data on a par with that presented in the 10 spotlighted articles. This will ensure that the scientific community at large can be confident in the data we report from optical biosensors.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Drysdale M, Heninger S, Hutt J, Chen Y, Lyons CR, Koehler TM. Capsule synthesis by Bacillus anthracis is required for dissemination in murine inhalation anthrax. EMBO J 2004; 24:221-7. [PMID: 15616593 PMCID: PMC544908 DOI: 10.1038/sj.emboj.7600495] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Accepted: 11/04/2004] [Indexed: 11/09/2022] Open
Abstract
Bacillus anthracis, the agent of anthrax, produces a poly-D-glutamic acid capsule that has been implicated in virulence. Many strains missing pXO2 (96 kb), which harbors the capsule biosynthetic operon capBCAD, but carrying pXO1 (182 kb) that harbors the anthrax toxin genes, are attenuated in animal models. Also, noncapsulated strains are readily phagocytosed by macrophage cell lines, whereas capsulated strains are resistant to phagocytosis. We show that a strain carrying both virulence plasmids but deleted specifically for capBCAD is highly attenuated in a mouse model for inhalation anthrax. The parent strain and capsule mutant initiated germination in the lungs, but the capsule mutant did not disseminate to the spleen. A mutant harboring capBCAD but deleted for the cap regulators acpA and acpB was also significantly attenuated, in agreement with the capsule-negative phenotype during in vitro growth. Surprisingly, an acpB mutant, but not an acpA mutant, displayed an elevated LD(50) and reduced ability to disseminate, indicating that acpA and acpB are not true functional homologs and that acpB may play a larger role in virulence than originally suspected.
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Affiliation(s)
- Melissa Drysdale
- Department of Microbiology and Molecular Genetics, The University of Texas Houston Health Science Center, Houston, TX, USA
| | - Sara Heninger
- Department of Internal Medicine, University of New Mexico Health Science Center, Albuquerque, NM, USA
| | - Julie Hutt
- Lovelace Respiratory Research Institute, Albuquerque, NM, USA
| | - Yahua Chen
- Department of Microbiology and Molecular Genetics, The University of Texas Houston Health Science Center, Houston, TX, USA
| | - C Rick Lyons
- Department of Internal Medicine, University of New Mexico Health Science Center, Albuquerque, NM, USA
| | - Theresa M Koehler
- Department of Microbiology and Molecular Genetics, The University of Texas Houston Health Science Center, Houston, TX, USA
- Department of Microbiology and Molecular Genetics, University of Texas Houston Health Science Center Medical School, 6431 Fannin St, JFB 1.765, Houston, TX 77030, USA. Tel.: +1 713 500 5450; Fax: +1 713 500 5499; E-mail:
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