1
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Bhattacharya M, Horswill AR. The role of human extracellular matrix proteins in defining Staphylococcus aureus biofilm infections. FEMS Microbiol Rev 2024; 48:fuae002. [PMID: 38337187 PMCID: PMC10873506 DOI: 10.1093/femsre/fuae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 01/26/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024] Open
Abstract
Twenty to forty one percent of the world's population is either transiently or permanently colonized by the Gram-positive bacterium, Staphylococcus aureus. In 2017, the CDC designated methicillin-resistant S. aureus (MRSA) as a serious threat, reporting ∼300 000 cases of MRSA-associated hospitalizations annually, resulting in over 19 000 deaths, surpassing that of HIV in the USA. S. aureus is a proficient biofilm-forming organism that rapidly acquires resistance to antibiotics, most commonly methicillin (MRSA). This review focuses on a large group of (>30) S. aureus adhesins, either surface-associated or secreted that are designed to specifically bind to 15 or more of the proteins that form key components of the human extracellular matrix (hECM). Importantly, this includes hECM proteins that are pivotal to the homeostasis of almost every tissue environment [collagen (skin), proteoglycans (lung), hemoglobin (blood), elastin, laminin, fibrinogen, fibronectin, and fibrin (multiple organs)]. These adhesins offer S. aureus the potential to establish an infection in every sterile tissue niche. These infections often endure repeated immune onslaught, developing into chronic, biofilm-associated conditions that are tolerant to ∼1000 times the clinically prescribed dose of antibiotics. Depending on the infection and the immune response, this allows S. aureus to seamlessly transition from colonizer to pathogen by subtly manipulating the host against itself while providing the time and stealth that it requires to establish and persist as a biofilm. This is a comprehensive discussion of the interaction between S. aureus biofilms and the hECM. We provide particular focus on the role of these interactions in pathogenesis and, consequently, the clinical implications for the prevention and treatment of S. aureus biofilm infections.
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Affiliation(s)
- Mohini Bhattacharya
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
- Department of Veterans Affairs, Eastern Colorado Health Care System, Aurora, CO 80045, United States
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2
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Sigmund F, Berezin O, Beliakova S, Magerl B, Drawitsch M, Piovesan A, Gonçalves F, Bodea SV, Winkler S, Bousraou Z, Grosshauser M, Samara E, Pujol-Martí J, Schädler S, So C, Irsen S, Walch A, Kofler F, Piraud M, Kornfeld J, Briggman K, Westmeyer GG. Genetically encoded barcodes for correlative volume electron microscopy. Nat Biotechnol 2023; 41:1734-1745. [PMID: 37069313 PMCID: PMC10713455 DOI: 10.1038/s41587-023-01713-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 02/14/2023] [Indexed: 04/19/2023]
Abstract
While genetically encoded reporters are common for fluorescence microscopy, equivalent multiplexable gene reporters for electron microscopy (EM) are still scarce. Here, by installing a variable number of fixation-stable metal-interacting moieties in the lumen of encapsulin nanocompartments of different sizes, we developed a suite of spherically symmetric and concentric barcodes (EMcapsulins) that are readable by standard EM techniques. Six classes of EMcapsulins could be automatically segmented and differentiated. The coding capacity was further increased by arranging several EMcapsulins into distinct patterns via a set of rigid spacers of variable length. Fluorescent EMcapsulins were expressed to monitor subcellular structures in light and EM. Neuronal expression in Drosophila and mouse brains enabled the automatic identification of genetically defined cells in EM. EMcapsulins are compatible with transmission EM, scanning EM and focused ion beam scanning EM. The expandable palette of genetically controlled EM-readable barcodes can augment anatomical EM images with multiplexed gene expression maps.
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Affiliation(s)
- Felix Sigmund
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Oleksandr Berezin
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Sofia Beliakova
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Bernhard Magerl
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Martin Drawitsch
- Research Group, Circuits of Birdsong, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | - Alberto Piovesan
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Filipa Gonçalves
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Silviu-Vasile Bodea
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Stefanie Winkler
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Zoe Bousraou
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Martin Grosshauser
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany
| | - Eleni Samara
- Department Circuits-Computation-Models, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | - Jesús Pujol-Martí
- Department Circuits-Computation-Models, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | | | - Chun So
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Goettingen, Germany
| | - Stephan Irsen
- Max Planck Institute for Neurobiology of Behavior-caesar (MPINB), Bonn, Germany
| | - Axel Walch
- Research Unit Analytical Pathology, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Marie Piraud
- Helmholtz AI, Helmholtz Munich, Neuherberg, Germany
| | - Joergen Kornfeld
- Research Group, Circuits of Birdsong, Max Planck Institute for Biological Intelligence, Martinsried, Germany
| | - Kevin Briggman
- Max Planck Institute for Neurobiology of Behavior-caesar (MPINB), Bonn, Germany
| | - Gil Gregor Westmeyer
- Munich Institute of Biomedical Engineering, Department of Bioscience, TUM School of Natural Sciences and TUM School of Medicine, Technical University of Munich, Munich, Germany.
- Institute for Synthetic Biomedicine, Helmholtz Munich, Neuherberg, Germany.
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3
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Boni R, Blackburn EA, Kleinjan DJ, Jonaitis M, Hewitt-Harris F, Murdoch M, Rosser S, Hay DC, Regan L. Chemically cross-linked hydrogels from repetitive protein arrays. J Struct Biol 2023; 215:107981. [PMID: 37245604 DOI: 10.1016/j.jsb.2023.107981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 05/19/2023] [Accepted: 05/23/2023] [Indexed: 05/30/2023]
Abstract
Biomaterials for tissue regeneration must mimic the biophysical properties of the native physiological environment. A protein engineering approach allows the generation of protein hydrogels with specific and customised biophysical properties designed to suit a particular physiological environment. Herein, repetitive engineered proteins were successfully designed to form covalent molecular networks with defined physical characteristics able to sustain cell phenotype. Our hydrogel design was made possible by the incorporation of the SpyTag (ST) peptide and multiple repetitive units of the SpyCatcher (SC) protein that spontaneously formed covalent crosslinks upon mixing. Changing the ratios of the protein building blocks (ST:SC), allowed the viscoelastic properties and gelation speeds of the hydrogels to be altered and controlled. The physical properties of the hydrogels could readily be altered further to suit different environments by tuning the key features in the repetitive protein sequence. The resulting hydrogels were designed with a view to allow cell attachment and encapsulation of liver derived cells. Biocompatibility of the hydrogels was assayed using a HepG2 cell line constitutively expressing GFP. The cells remained viable and continued to express GFP whilst attached or encapsulated within the hydrogel. Our results demonstrate how this genetically encoded approach using repetitive proteins could be applied to bridge engineering biology with nanotechnology creating a level of biomaterial customisation previously inaccessible.
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Affiliation(s)
- Rossana Boni
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Elizabeth A Blackburn
- Edinburgh Protein Production Facility (EPPF), University of Edinburgh, Edinburgh, United Kingdom
| | - Dirk-Jan Kleinjan
- UK Centre for Mammalian Synthetic Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mantas Jonaitis
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| | - Flora Hewitt-Harris
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Megan Murdoch
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Susan Rosser
- UK Centre for Mammalian Synthetic Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - David C Hay
- Centre for Regenerative Medicine, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| | - Lynne Regan
- Centre for Engineering Biology, Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom.
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4
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Vo LH, Hong S, Stepler KE, Liyanaarachchi SM, Yang J, Nemes P, Poulin MB. Mapping protein-exopolysaccharide binding interaction in Staphylococcus epidermidis biofilms by live cell proximity labeling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.29.555326. [PMID: 37693546 PMCID: PMC10491226 DOI: 10.1101/2023.08.29.555326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Bacterial biofilms consist of cells encased in an extracellular polymeric substance (EPS) composed of exopolysaccharides, extracellular DNA, and proteins that are critical for cell-cell adhesion and protect the cells from environmental stress, antibiotic treatments, and the host immune response. Degrading EPS components or blocking their production have emerged as promising strategies for prevention or dispersal of bacterial biofilms, but we still have little information about the specific biomolecular interactions that occur between cells and EPS components and how those interactions contribute to biofilm production. Staphylococcus epidermidis is a leading cause of nosocomial infections as a result of producing biofilms that use the exopolysaccharide poly-(1→6)-β-N-acetylglucosamine (PNAG) as a major structural component. In this study, we have developed a live cell proximity labeling approach combined with quantitative mass spectrometry-based proteomics to map the PNAG interactome of live S. epidermidis biofilms. Through these measurements we discovered elastin-binding protein (EbpS) as a major PNAG-interacting protein. Using live cell binding measurements, we found that the lysin motif (LysM) domain of EbpS specifically binds to PNAG present in S. epidermidis biofilms. Our work provides a novel method for the rapid identification of exopolysaccharide-binding proteins in live biofilms that will help to extend our understanding of the biomolecular interactions that are required for bacterial biofilm formation.
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Affiliation(s)
- Luan H. Vo
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Steven Hong
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Kaitlyn E. Stepler
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Sureshee M. Liyanaarachchi
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Jack Yang
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Peter Nemes
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
| | - Myles B. Poulin
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, United States
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5
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Boni R, Regan L. Modulating the Viscoelastic Properties of Covalently Crosslinked Protein Hydrogels. Gels 2023; 9:481. [PMID: 37367151 DOI: 10.3390/gels9060481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/22/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023] Open
Abstract
Protein engineering allows for the programming of specific building blocks to form functional and novel materials with customisable physical properties suitable for tailored engineering applications. We have successfully designed and programmed engineered proteins to form covalent molecular networks with defined physical characteristics. Our hydrogel design incorporates the SpyTag (ST) peptide and SpyCatcher (SC) protein that spontaneously form covalent crosslinks upon mixing. This genetically encodable chemistry allowed us to easily incorporate two stiff and rod-like recombinant proteins in the hydrogels and modulate the resulting viscoelastic properties. We demonstrated how differences in the composition of the microscopic building blocks change the macroscopic viscoelastic properties of the hydrogels. We specifically investigated how the identity of the protein pairs, the molar ratio of ST:SC, and the concentration of the proteins influence the viscoelastic response of the hydrogels. By showing tuneable changes in protein hydrogel rheology, we increased the capabilities of synthetic biology to create novel materials, allowing engineering biology to interface with soft matter, tissue engineering, and material science.
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Affiliation(s)
- Rossana Boni
- Centre for Engineering Biology, School of Biological Sciences, Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3FF, UK
| | - Lynne Regan
- Centre for Engineering Biology, School of Biological Sciences, Institute of Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3FF, UK
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6
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Yadav R, Shaikh T, Tikole S, Herr AB, Fitzkee NC. 1H, 15N, and 13C chemical shift backbone resonance NMR assignment of the accumulation-associated protein (Aap) lectin domain from Staphylococcus epidermidis. BIOMOLECULAR NMR ASSIGNMENTS 2023; 17:95-99. [PMID: 37022616 PMCID: PMC10247473 DOI: 10.1007/s12104-023-10126-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Accepted: 03/30/2023] [Indexed: 06/02/2023]
Abstract
Staphylococcus epidermidis is the leading causative agent for hospital-acquired infections, especially device-related infections, due to its ability to form biofilms. The accumulation-associated protein (Aap) of S. epidermidis is primarily responsible for biofilm formation and consists of two domains, A and B. It was found that the A domain is responsible for the attachment to the abiotic/biotic surface, whereas the B domain is responsible for the accumulation of bacteria during biofilm formation. One of the parts of the A domain is the Aap lectin, which is a carbohydrate-binding domain having 222 amino acids in its structure. Here we report the near complete backbone chemical shift assignments for the lectin domain, as well as its predicted secondary structure. This data will provide a platform for future NMR studies to explore the role of lectin in biofilm formation.
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Affiliation(s)
- Rahul Yadav
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA
- Physical Sciences Department, University of Arkansas, Ft. Smith, AR, 72913, USA
| | - Tanveer Shaikh
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA
| | - Suhas Tikole
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA
| | - Andrew B Herr
- Department of Pediatrics, Division of Immunobiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati School of Medicine, Cincinnati, OH, 45229, USA
| | - Nicholas C Fitzkee
- Department of Chemistry, Mississippi State University, Starkville, MS, 39762, USA.
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7
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Collagen-like Motifs of SasG: A Novel Fold for Protein Mechanical Strength. J Mol Biol 2023; 435:167980. [PMID: 36708761 DOI: 10.1016/j.jmb.2023.167980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/11/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023]
Abstract
The Staphylococcus aureus surface protein G (SasG) is associated with host colonisation and biofilm formation. As colonisation occurs at the liquid-substrate interface bacteria are subject to a myriad of external forces and, presumably as a consequence, SasG displays extreme mechanical strength. This mechanical phenotype arises from the B-domain; a repetitive region composed of alternating E and G5 subdomains. These subdomains have an unusual structure comprising collagen-like regions capped by triple-stranded β-sheets. To identify the determinants of SasG mechanical strength, we characterised the mechanical phenotype and thermodynamic stability of 18 single substitution variants of a pseudo-wildtype protein. Visualising the mechanically-induced transition state at a residue-level by ϕ-value analysis reveals that the main force-bearing regions are the N- and C-terminal 'Mechanical Clamps' and their side-chain interactions. This is tailored by contacts at the pseudo-hydrophobic core interface. We also describe a novel mechanical motif - the collagen-like region and show that glycine to alanine substitutions, analogous to those found in Osteogenesis Imperfecta (brittle bone disease), result in a significantly reduced mechanical strength.
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8
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Clark LC, Atkin KE, Whelan F, Brentnall AS, Harris G, Towell AM, Turkenburg JP, Liu Y, Feizi T, Griffiths SC, Geoghegan JA, Potts JR. Staphylococcal Periscope proteins Aap, SasG, and Pls project noncanonical legume-like lectin adhesin domains from the bacterial surface. J Biol Chem 2023; 299:102936. [PMID: 36702253 PMCID: PMC9999234 DOI: 10.1016/j.jbc.2023.102936] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 01/08/2023] [Accepted: 01/18/2023] [Indexed: 01/25/2023] Open
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are frequently associated with medical device infections that involve establishment of a bacterial biofilm on the device surface. Staphylococcal surface proteins Aap, SasG, and Pls are members of the Periscope Protein class and have been implicated in biofilm formation and host colonization; they comprise a repetitive region ("B region") and an N-terminal host colonization domain within the "A region," predicted to be a lectin domain. Repetitive E-G5 domains (as found in Aap, SasG, and Pls) form elongated "stalks" that would vary in length with repeat number, resulting in projection of the N-terminal A domain variable distances from the bacterial cell surface. Here, we present the structures of the lectin domains within A regions of SasG, Aap, and Pls and a structure of the Aap lectin domain attached to contiguous E-G5 repeats, suggesting the lectin domains will sit at the tip of the variable length rod. We demonstrate that these isolated domains (Aap, SasG) are sufficient to bind to human host desquamated nasal epithelial cells. Previously, proteolytic cleavage or a deletion within the A domain had been reported to induce biofilm formation; the structures suggest a potential link between these observations. Intriguingly, while the Aap, SasG, and Pls lectin domains bind a metal ion, they lack the nonproline cis peptide bond thought to be key for carbohydrate binding by the lectin fold. This suggestion of noncanonical ligand binding should be a key consideration when investigating the host cell interactions of these bacterial surface proteins.
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Affiliation(s)
- Laura C Clark
- Department of Biology, University of York, York, United Kingdom
| | - Kate E Atkin
- Department of Biology, University of York, York, United Kingdom
| | - Fiona Whelan
- Department of Biology, University of York, York, United Kingdom; Department of Molecular and Biomedical Science, School of Biological Sciences, University of Adelaide, South Australia, Australia.
| | | | - Gemma Harris
- Department of Biology, University of York, York, United Kingdom
| | - Aisling M Towell
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland
| | | | - Yan Liu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Ten Feizi
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London, United Kingdom
| | | | - Joan A Geoghegan
- Department of Microbiology, Moyne Institute of Preventive Medicine, School of Genetics and Microbiology, Trinity College Dublin, Dublin, Ireland; Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Jennifer R Potts
- Department of Biology, University of York, York, United Kingdom; School of Life and Environmental Sciences, University of Sydney, New South Wales, Australia.
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9
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Maciag JJ, Chantraine C, Mills KB, Yadav R, Yarawsky AE, Chaton CT, Vinod D, Fitzkee NC, Mathelié-Guinlet M, Dufrêne YF, Fey PD, Horswill AR, Herr AB. Mechanistic basis of staphylococcal interspecies competition for skin colonization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525635. [PMID: 36747832 PMCID: PMC9900903 DOI: 10.1101/2023.01.26.525635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Staphylococci, whether beneficial commensals or pathogens, often colonize human skin, potentially leading to competition for the same niche. In this multidisciplinary study we investigate the structure, binding specificity, and mechanism of adhesion of the Aap lectin domain required for Staphylococcus epidermidis skin colonization and compare its characteristics to the lectin domain from the orthologous Staphylococcus aureus adhesin SasG. The Aap structure reveals a legume lectin-like fold with atypical architecture, showing specificity for N-acetyllactosamine and sialyllactosamine. Bacterial adhesion assays using human corneocytes confirmed the biological relevance of these Aap-glycan interactions. Single-cell force spectroscopy experiments measured individual binding events between Aap and corneocytes, revealing an extraordinarily tight adhesion force of nearly 900 nN and a high density of receptors at the corneocyte surface. The SasG lectin domain shares similar structural features, glycan specificity, and corneocyte adhesion behavior. We observe cross-inhibition of Aap-and SasG-mediated staphylococcal adhesion to corneocytes. Together, these data provide insights into staphylococcal interspecies competition for skin colonization and suggest potential avenues for inhibition of S. aureus colonization.
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Affiliation(s)
- Joseph J. Maciag
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Constance Chantraine
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Krista B. Mills
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Rahul Yadav
- Department of Chemistry, Mississippi State University, Mississippi State, MS
| | - Alexander E. Yarawsky
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Catherine T. Chaton
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Divya Vinod
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
- Medical Sciences Undergraduate Program, University of Cincinnati, Cincinnati, OH
| | - Nicholas C. Fitzkee
- Department of Chemistry, Mississippi State University, Mississippi State, MS
| | - Marion Mathelié-Guinlet
- Institut de Chimie et Biologie des Membranes et des Nano-Objets, CNRS UMR 5248, University of Bordeaux, Pessac, France
| | - Yves F. Dufrêne
- Louvain Institute of Biomolecular Science and Technology, UCLouvain, Louvain-la-Neuve, Belgium
| | - Paul D. Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE
| | - Alexander R. Horswill
- Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO
| | - Andrew B. Herr
- Division of Immunobiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
- Division of Infectious Diseases, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
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10
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Regulation of Staphylococcus aureus Virulence and Application of Nanotherapeutics to Eradicate S. aureus Infection. Pharmaceutics 2023; 15:pharmaceutics15020310. [PMID: 36839634 PMCID: PMC9960757 DOI: 10.3390/pharmaceutics15020310] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/19/2023] Open
Abstract
Staphylococcus aureus is a versatile pathogen known to cause hospital- and community-acquired, foodborne, and zoonotic infections. The clinical infections by S. aureus cause an increase in morbidity and mortality rates and treatment costs, aggravated by the emergence of drug-resistant strains. As a multi-faceted pathogen, it is imperative to consolidate the knowledge on its pathogenesis, including the mechanisms of virulence regulation, development of antimicrobial resistance, and biofilm formation, to make it amenable to different treatment strategies. Nanomaterials provide a suitable platform to address this challenge, with the potential to control intracellular parasitism and multidrug resistance where conventional therapies show limited efficacy. In a nutshell, the first part of this review focuses on the impact of S. aureus on human health and the role of virulence factors and biofilms during pathogenesis. The second part discusses the large diversity of nanoparticles and their applications in controlling S. aureus infections, including combination with antibiotics and phytochemicals and the incorporation of antimicrobial coatings for biomaterials. Finally, the limitations and prospects using nanomaterials are highlighted, aiming to foster the development of novel nanotechnology-driven therapies against multidrug-resistant S. aureus.
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11
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The long and the short of Periscope Proteins. Biochem Soc Trans 2022; 50:1293-1302. [PMID: 36196877 DOI: 10.1042/bst20220194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/10/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022]
Abstract
Bacteria sense, interact with, and modify their environmental niche by deploying a molecular ensemble at the cell surface. The changeability of this exposed interface, combined with extreme changes in the functional repertoire associated with lifestyle switches from planktonic to adherent and biofilm states necessitate dynamic variability. Dynamic surface changes include chemical modifications to the cell wall; export of diverse extracellular biofilm components; and modulation of expression of cell surface proteins for adhesion, co-aggregation and virulence. Local enrichment for highly repetitive proteins with high tandem repeat identity has been an enigmatic phenomenon observed in diverse bacterial species. Preliminary observations over decades of research suggested these repeat regions were hypervariable, as highly related strains appeared to express homologues with diverse molecular mass. Long-read sequencing data have been interrogated to reveal variation in repeat number; in combination with structural, biophysical and molecular dynamics approaches, the Periscope Protein class has been defined for cell surface attached proteins that dynamically expand and contract tandem repeat tracts at the population level. Here, I review the diverse high-stability protein folds and coherent interdomain linkages culminating in the formation of highly anisotropic linear repeat arrays, so-called rod-like protein 'stalks', supporting roles in bacterial adhesion, biofilm formation, cell surface spatial competition, and immune system modulation. An understanding of the functional impacts of dynamic changes in repeat arrays and broader characterisation of the unusual protein folds underpinning this variability will help with the design of immunisation strategies, and contribute to synthetic biology approaches including protein engineering and microbial consortia construction.
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12
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Mousanezhad S, Davoodi J. Mechanical loading of graphene quantum dots on
Staphylococcus aureus
surface protein G: A molecular dynamics study. Biopolymers 2022; 113:e23526. [DOI: 10.1002/bip.23526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 08/25/2022] [Accepted: 09/01/2022] [Indexed: 11/08/2022]
Affiliation(s)
| | - Jamal Davoodi
- Department of Physics University of Zanjan Zanjan Iran
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13
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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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14
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Sharma S, Meena M, Marwal A, Swapnil P. Biofilm matrix proteins. APPLICATION OF BIOFILMS IN APPLIED MICROBIOLOGY 2022:51-64. [DOI: 10.1016/b978-0-323-90513-8.00007-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
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15
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Glycan-Dependent Corneocyte Adherence of Staphylococcus epidermidis Mediated by the Lectin Subdomain of Aap. mBio 2021; 12:e0290820. [PMID: 34253065 PMCID: PMC8406310 DOI: 10.1128/mbio.02908-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Staphylococcus epidermidis and other coagulase-negative staphylococci (CoNS) that colonize skin are known to promote skin immunity and inhibit colonization of pathogens that cause skin and soft tissue infections, including Staphylococcus aureus. However, S. epidermidis adherence to corneocytes, the cells that constitute the uppermost layer of the skin epidermis, remains poorly understood. Our study documents that S. epidermidis corneocyte adherence is dependent upon the accumulation-associated protein (Aap). Aap is composed of two distinct A and B domains. The A domain is comprised of a repeat region and a conserved L-type lectin domain, whereas the fibrillar B domain, which is comprised of G5 and E repeats, is linked to the cell wall in a sortase-dependent manner. Our studies revealed that adherence to corneocytes is dependent upon the lectin subdomain within the A domain. However, significant adherence was only observed when the lectin domain was expressed with both the A repeat and the B domain, suggesting further interactions between these three domains. Our data also suggest that the A repeat domain is important for stability or expression of Aap. Deglycosylation treatment suggested that glycans expressed in the host stratum corneum serve as potential binding partners for Aap-mediated corneocyte adherence. Last, bioinformatic analyses of the predominant commensal species of CoNS identified open reading frames (ORFs) homologous to aap, thus suggesting that Aap orthologues containing lectin-like domains may provide the basis for staphylococcal colonization of skin. Corroborating these observations, adherence to corneocytes in an S. aureus mgrA mutant was dependent upon SasG, the Aap orthologue in S. aureus. IMPORTANCE Staphylococcus aureus is the most significant cause of skin and soft tissue infections yet it rarely colonizes the skin of healthy individuals. This is believed to be due, in part, to inhibition of colonization via toxic substances produced by normal skin flora, including by S. epidermidis. Furthermore, we surmise that S. aureus colonization inhibition may also be due to competition for binding sites on host corneocytes. To understand these potential interactions between S. aureus and S. epidermidis and, potentially, other coagulase-negative staphylococci, we must first understand how staphylococci adhere to corneocytes. This work documents that S. epidermidis adherence to corneocytes is dependent upon the fibrillar cell wall-associated protein Aap. Our work further documents that Aap binds to glycans exposed on the corneocyte surface, which are commonly exploited by bacteria to facilitate adherence to host cells. Furthermore, we find that Aap orthologues may be responsible for corneocyte adherence in other staphylococci, including in S. aureus.
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16
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Periscope Proteins are variable-length regulators of bacterial cell surface interactions. Proc Natl Acad Sci U S A 2021; 118:2101349118. [PMID: 34074781 PMCID: PMC8201768 DOI: 10.1073/pnas.2101349118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The structure of single and tandem SHIRT domains from the streptococcal surface protein Sgo_0707 were determined. In conjunction with biophysics and molecular dynamics simulations, the results show that the observed gene length variation would result in differential projection of the host ligand binding domain on the bacterial cell surface. An analysis of long-read DNA sequence data reveals many other repetitive bacterial surface proteins that appear to undergo gene length variation. We propose that these variable-length “Periscope Proteins” represent an important mechanism of bacterial cell surface modification with potential roles in infection and immune evasion. Changes at the cell surface enable bacteria to survive in dynamic environments, such as diverse niches of the human host. Here, we reveal “Periscope Proteins” as a widespread mechanism of bacterial surface alteration mediated through protein length variation. Tandem arrays of highly similar folded domains can form an elongated rod-like structure; thus, variation in the number of domains determines how far an N-terminal host ligand binding domain projects from the cell surface. Supported by newly available long-read genome sequencing data, we propose that this class could contain over 50 distinct proteins, including those implicated in host colonization and biofilm formation by human pathogens. In large multidomain proteins, sequence divergence between adjacent domains appears to reduce interdomain misfolding. Periscope Proteins break this “rule,” suggesting that their length variability plays an important role in regulating bacterial interactions with host surfaces, other bacteria, and the immune system.
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17
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Mirzaei B, Babaei R, Valinejad S. Staphylococcal Vaccine Antigens related to biofilm formation. Hum Vaccin Immunother 2021; 17:293-303. [PMID: 32498595 PMCID: PMC7872035 DOI: 10.1080/21645515.2020.1767449] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 05/05/2020] [Indexed: 10/24/2022] Open
Abstract
The number and frequency of multidrug-resistant (MDR) strains as a frequent cause of nosocomial infections have increased, especially for Methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis, in part due to device-related infections. The transition to antibiotic-resistance in related bacterial genes and the capability for immune escape have increased the sustainability of biofilms produced by these bacteria. The formation and changes in biofilms have been suggested as a target to prevent or treat staphylococcal infections. Thus, this study reviews the development of candidate staphylococcal vaccines by database searching, and evaluates the immunogenicity and efficacy profiles of bacterial components involved in biofilms. The literature suggests that using common staphylococcal vaccine antigens and multivalent vaccines should further enhance vaccine efficacy.
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Affiliation(s)
- Bahman Mirzaei
- Department of Medical Microbiology and Virology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
- Department of Medical Microbiology and Virology, School of Medicine, Zanjan University of Medical Science, Zanjan, Iran
| | - Ryhaneh Babaei
- Department of Medical Microbiology and Virology, School of Medicine, Zanjan University of Medical Science, Zanjan, Iran
| | - Sina Valinejad
- Department of Medical Microbiology and Virology, School of Medicine, Zanjan University of Medical Science, Zanjan, Iran
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18
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Acetylation of Surface Carbohydrates in Bacterial Pathogens Requires Coordinated Action of a Two-Domain Membrane-Bound Acyltransferase. mBio 2020; 11:mBio.01364-20. [PMID: 32843546 PMCID: PMC7448272 DOI: 10.1128/mbio.01364-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acyltransferase-3 (AT3) domain-containing membrane proteins are involved in O-acetylation of a diverse range of carbohydrates across all domains of life. In bacteria they are essential in processes including symbiosis, resistance to antimicrobials, and biosynthesis of antibiotics. Their mechanism of action, however, is poorly characterized. We analyzed two acetyltransferases as models for this important family of membrane proteins, which modify carbohydrates on the surface of the pathogen Salmonella enterica, affecting immunogenicity, virulence, and bacteriophage resistance. We show that when these AT3 domains are fused to a periplasmic partner domain, both domains are required for substrate acetylation. The data show conserved elements in the AT3 domain and unique structural features of the periplasmic domain. Our data provide a working model to probe the mechanism and function of the diverse and important members of the widespread AT3 protein family, which are required for biologically significant modifications of cell-surface carbohydrates. Membrane bound acyltransferase-3 (AT3) domain-containing proteins are implicated in a wide range of carbohydrate O-acyl modifications, but their mechanism of action is largely unknown. O-antigen acetylation by AT3 domain-containing acetyltransferases of Salmonella spp. can generate a specific immune response upon infection and can influence bacteriophage interactions. This study integrates in situ and in vitro functional analyses of two of these proteins, OafA and OafB (formerly F2GtrC), which display an “AT3-SGNH fused” domain architecture, where an integral membrane AT3 domain is fused to an extracytoplasmic SGNH domain. An in silico-inspired mutagenesis approach of the AT3 domain identified seven residues which are fundamental for the mechanism of action of OafA, with a particularly conserved motif in TMH1 indicating a potential acyl donor interaction site. Genetic and in vitro evidence demonstrate that the SGNH domain is both necessary and sufficient for lipopolysaccharide acetylation. The structure of the periplasmic SGNH domain of OafB identified features not previously reported for SGNH proteins. In particular, the periplasmic portion of the interdomain linking region is structured. Significantly, this region constrains acceptor substrate specificity, apparently by limiting access to the active site. Coevolution analysis of the two domains suggests possible interdomain interactions. Combining these data, we propose a refined model of the AT3-SGNH proteins, with structurally constrained orientations of the two domains. These findings enhance our understanding of how cells can transfer acyl groups from the cytoplasm to specific extracellular carbohydrates.
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19
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Foster TJ. Surface Proteins of Staphylococcus epidermidis. Front Microbiol 2020; 11:1829. [PMID: 32849430 PMCID: PMC7403478 DOI: 10.3389/fmicb.2020.01829] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/13/2020] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus epidermidis is a ubiquitous commensal of human skin. The widespread use of indwelling medical devices in modern medicine provides an opportunity for it to cause infections. Disease causing isolates can come from many different genetic backgrounds. Multiply antibiotic resistant strains have spread globally. S. epidermidis has a smaller repertoire of cell wall anchored (CWA) surface proteins than Staphylococcus aureus. Nevertheless, these CWA proteins promote adhesion to components of the extracellular matrix including collagen, fibrinogen, and fibronectin and contribute to the formation of biofilm. The A domain of the accumulation associated protein Aap can promote adhesion to unconditioned biomaterial but must be removed proteolytically to allow accumulation to proceed by homophilic Zn2+-dependent interactions. Mature biofilm contains amyloid structures formed by Aap and the small basic protein (Sbp). The latter contributes to the integrity of both protein and polysaccharide biofilm matrices. Several other CWA proteins can also promote S. epidermidis biofilm formation.
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Affiliation(s)
- Timothy J Foster
- Department of Microbiology, Trinity College Dublin, Dublin, Ireland
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20
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Jasaitis L, Silver CD, Rawlings AE, Peters DT, Whelan F, Regan L, Pasquina-Lemonche L, Potts JR, Johnson SD, Staniland SS. Rational Design and Self-Assembly of Coiled-Coil Linked SasG Protein Fibrils. ACS Synth Biol 2020; 9:1599-1607. [PMID: 32551507 DOI: 10.1021/acssynbio.0c00156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein engineering is an attractive approach for the self-assembly of nanometer-scale architectures for a range of potential nanotechnologies. Using the versatile chemistry provided by protein folding and assembly, coupled with amino acid side-chain functionality, allows for the construction of precise molecular "protein origami" hierarchical patterned structures for a range of nanoapplications such as stand-alone enzymatic pathways and molecular machines. The Staphyloccocus aureus surface protein SasG is a rigid, rod-like structure shown to have high mechanical strength due to "clamp-like" intradomain features and a stabilizing interface between the G5 and E domains, making it an excellent building block for molecular self-assembly. Here we characterize a new two subunit system composed of the SasG rod protein genetically conjugated with de novo designed coiled-coils, resulting in the self-assembly of fibrils. Circular dichroism (CD) and quartz-crystal microbalance with dissipation (QCM-D) are used to show the specific, alternating binding between the two subunits. Furthermore, we use atomic force microscopy (AFM) to study the extent of subunit polymerization in a liquid environment, demonstrating self-assembly culminating in the formation of linear macromolecular fibrils.
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Affiliation(s)
- Lukas Jasaitis
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Callum D. Silver
- Department of Electronic Engineering, University of York, York YO10 5DD, United Kingdom
| | - Andrea E. Rawlings
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Daniel T. Peters
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Fiona Whelan
- School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Lynne Regan
- Institute for Quantitative Biology, Biochemistry and Biotechnology, University of Edinburgh, Edinburgh EH9 3JU, Scotland
| | - Laia Pasquina-Lemonche
- Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Jennifer R. Potts
- School of Life and Environmental Science, University of Sydney, Sydney, NSW 2006, Australia
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Steven D. Johnson
- Department of Electronic Engineering, University of York, York YO10 5DD, United Kingdom
| | - Sarah S. Staniland
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, United Kingdom
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21
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Yarawsky AE, Herr AB. The staphylococcal biofilm protein Aap forms a tetrameric species as a necessary intermediate before amyloidogenesis. J Biol Chem 2020; 295:12840-12850. [PMID: 32665400 DOI: 10.1074/jbc.ra120.013936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/29/2020] [Indexed: 11/06/2022] Open
Abstract
The accumulation-associated protein (Aap) from Staphylococcus epidermidis is a biofilm-related protein that was found to be a critical factor for infection using a rat catheter model. The B-repeat superdomain of Aap, composed of 5-17 B-repeats, each containing a Zn2+-binding G5 and a spacer subdomain, is responsible for Zn2+-dependent assembly leading to accumulation of bacteria during biofilm formation. We previously demonstrated that a minimal B-repeat construct (Brpt1.5) forms an antiparallel dimer in the presence of 2-3 Zn2+ ions. More recently, we have reported the presence of functional amyloid-like fibrils composed of Aap within S. epidermidis biofilms and demonstrated that a biologically relevant construct containing five and a half B-repeats (Brpt5.5) forms amyloid-like fibrils similar to those observed in the biofilm. In this study, we analyze the initial assembly events of the Brpt5.5 construct. Analytical ultracentrifugation was utilized to determine hydrodynamic parameters of reversibly associating species and to perform linked equilibrium studies. Linkage studies indicated a mechanism of Zn2+-induced dimerization similar to smaller constructs; however, Brpt5.5 dimers could then undergo further Zn2+-induced assembly into a previously uncharacterized tetramer. This led us to search for potential Zn2+-binding sites outside of the dimer interface. We developed a Brpt5.5 mutant that was unable to form the tetramer and was concordantly incapable of amyloidogenesis. CD and dynamic light scattering indicate that a conformational transition in the tetramer species is a critical step preceding amyloidogenesis. This mechanistic model for B-repeat assembly and amyloidogenesis provides new avenues for potential therapeutic targeting of staphylococcal biofilms.
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Affiliation(s)
- Alexander E Yarawsky
- Graduate Program in Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA; Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Andrew B Herr
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA; Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
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22
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Back CR, Higman VA, Le Vay K, Patel VV, Parnell AE, Frankel D, Jenkinson HF, Burston SG, Crump MP, Nobbs AH, Race PR. The streptococcal multidomain fibrillar adhesin CshA has an elongated polymeric architecture. J Biol Chem 2020; 295:6689-6699. [PMID: 32229583 PMCID: PMC7212634 DOI: 10.1074/jbc.ra119.011719] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/26/2020] [Indexed: 11/06/2022] Open
Abstract
The cell surfaces of many bacteria carry filamentous polypeptides termed adhesins that enable binding to both biotic and abiotic surfaces. Surface adherence is facilitated by the exquisite selectivity of the adhesins for their cognate ligands or receptors and is a key step in niche or host colonization and pathogenicity. Streptococcus gordonii is a primary colonizer of the human oral cavity and an opportunistic pathogen, as well as a leading cause of infective endocarditis in humans. The fibrillar adhesin CshA is an important determinant of S. gordonii adherence, forming peritrichous fibrils on its surface that bind host cells and other microorganisms. CshA possesses a distinctive multidomain architecture comprising an N-terminal target-binding region fused to 17 repeat domains (RDs) that are each ∼100 amino acids long. Here, using structural and biophysical methods, we demonstrate that the intact CshA repeat region (CshA_RD1-17, domains 1-17) forms an extended polymeric monomer in solution. We recombinantly produced a subset of CshA RDs and found that they differ in stability and unfolding behavior. The NMR structure of CshA_RD13 revealed a hitherto unreported all β-fold, flanked by disordered interdomain linkers. These findings, in tandem with complementary hydrodynamic studies of CshA_RD1-17, indicate that this polypeptide possesses a highly unusual dynamic transitory structure characterized by alternating regions of order and disorder. This architecture provides flexibility for the adhesive tip of the CshA fibril to maintain bacterial attachment that withstands shear forces within the human host. It may also help mitigate deleterious folding events between neighboring RDs that share significant structural identity without compromising mechanical stability.
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Affiliation(s)
- Catherine R Back
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Victoria A Higman
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Kristian Le Vay
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- Bristol Centre for Functional Nanomaterials, H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom
| | - Viren V Patel
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Alice E Parnell
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Daniel Frankel
- School of Engineering, Newcastle University, Newcastle-upon-Tyne NE1 7RU, United Kingdom
| | - Howard F Jenkinson
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Steven G Burston
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Matthew P Crump
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
- School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Angela H Nobbs
- Bristol Dental School, University of Bristol, Bristol BS1 2LY, United Kingdom
| | - Paul R Race
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
- BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, United Kingdom
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23
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Pinto F, Thornton EL, Wang B. An expanded library of orthogonal split inteins enables modular multi-peptide assemblies. Nat Commun 2020; 11:1529. [PMID: 32251274 PMCID: PMC7090010 DOI: 10.1038/s41467-020-15272-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 02/26/2020] [Indexed: 01/03/2023] Open
Abstract
Inteins are protein segments capable of joining adjacent residues via a peptide bond. In this process known as protein splicing, the intein itself is not present in the final sequence, thus achieving scarless peptide ligation. Here, we assess the splicing activity of 34 inteins (both uncharacterized and known) using a rapid split fluorescent reporter characterization platform, and establish a library of 15 mutually orthogonal split inteins for in vivo applications, 10 of which can be simultaneously used in vitro. We show that orthogonal split inteins can be coupled to multiple split transcription factors to implement complex logic circuits in living organisms, and that they can also be used for the in vitro seamless assembly of large repetitive proteins with biotechnological relevance. Our work demonstrates the versatility and vast potential of an expanded library of orthogonal split inteins for their use in the fields of synthetic biology and protein engineering.
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Affiliation(s)
- Filipe Pinto
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Ella Lucille Thornton
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK
| | - Baojun Wang
- School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FF, UK.
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, EH9 3FF, UK.
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24
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Yarawsky AE, Johns SL, Schuck P, Herr AB. The biofilm adhesion protein Aap from Staphylococcus epidermidis forms zinc-dependent amyloid fibers. J Biol Chem 2020; 295:4411-4427. [PMID: 32102851 DOI: 10.1074/jbc.ra119.010874] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/23/2020] [Indexed: 12/17/2022] Open
Abstract
The skin-colonizing commensal bacterium Staphylococcus epidermidis is a leading cause of hospital-acquired and device-related infections. Its pathogenicity in humans is largely due to its propensity to form biofilms, surface-adherent bacterial accumulations that are remarkably resistant to chemical and physical stresses. Accumulation-associated protein (Aap) from S. epidermidis has been shown to be necessary and sufficient for mature biofilm formation and catheter infection. Aap contains up to 17 tandem B-repeat domains, capable of zinc-dependent assembly into twisted, rope-like intercellular filaments in the biofilm. Using microscopic and biophysical techniques, we show here that Aap B-repeat constructs assemble further into zinc-dependent functional amyloid fibers. We observed such amyloid fibers by confocal microscopy during both early and late stages of S. epidermidis biofilm formation, and we confirmed that extracellular fibrils from these biofilms contain Aap. Unlike what has been observed for amyloidogenic biofilm proteins from other bacteria, which typically use chaperones or initiator proteins to initiate amyloid assembly, our findings indicate that Aap from S. epidermidis requires Zn2+ as a catalyst that drives amyloid fiber formation, similar to many mammalian amyloid-forming proteins that require metals for assembly. This work provides detailed insights into S. epidermidis biofilm formation and architecture that improve our understanding of persistent staphylococcal infections.
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Affiliation(s)
- Alexander E Yarawsky
- Graduate Program in Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267.,Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Stefanie L Johns
- Graduate Program in Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267
| | - Peter Schuck
- Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Bioengineering, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20814
| | - Andrew B Herr
- Division of Immunobiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229 .,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio 45229.,Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
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25
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Paukovich N, Redzic JS, Chi YC, Rahkola JT, Issaian A, Blue A, Hansen KC, Janoff EN, Eisenmesser EZ. Streptococcus pneumoniae G5 domains bind different ligands. Protein Sci 2019; 28:1797-1805. [PMID: 31390088 DOI: 10.1002/pro.3693] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/12/2019] [Accepted: 07/11/2019] [Indexed: 11/08/2022]
Abstract
Many bacterial pathogens express small G5 domains that exist in the context of various membrane-anchored proteins and these G5 domains have been associated with colonization, cellular adhesion, and biofilm formation. However, despite over a decade since the computational prediction of these G5 domains, many remain uncharacterized, particularly those from Streptococcus pneumoniae. Of five previously predicted G5 domains we found that four of these, all derived from S. pneumoniae, are independently folded modules. As one of these exhibits extreme line broadening due to self-association, we were able to use NMR solution studies to probe the potential ligand interactions of the remaining three G5 domains. None of these G5 domains engage N-acetylglucosamine (NAG) as previously predicted but do interact with other small molecules that may modulate adherence to both bacteria and host cells. Specifically, while all G5 domains tested engage Zn, only one of these G5 domains engage heparin. NMR solution structural studies of the IgA1 Protease G5 (IgA1P-G5) and endo-beta-N-acetylglucosaminidase-D G5 (ENDD-G5) also facilitated identification of the ligand binding sites and confirm the typical G5 fold that comprises two connected β-sheets with no canonical core. NMR relaxation experiments indicate flexibility on both ends and within the connecting regions between the β-sheets. Our studies thus establish a basis for future biological experiments to test whether the ligands presented here are involved in bacterial adherence, either to bacteria or to host cells.
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Affiliation(s)
- Natasia Paukovich
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Jasmina S Redzic
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Ying-Chih Chi
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Jeremy T Rahkola
- Mucosal and Vaccine Research Program Colorado (MAVRC) & Denver Veterans Affairs Medical Center, Aurora, Colorado
| | - Aaron Issaian
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Ashley Blue
- National High Magnetic Field Laboratory, Tallahassee, Florida
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado
| | - Edward N Janoff
- Mucosal and Vaccine Research Program Colorado (MAVRC) & Denver Veterans Affairs Medical Center, Aurora, Colorado
| | - Elan Z Eisenmesser
- Department of Biochemistry and Molecular Genetics, School of Medicine, University of Colorado Denver, School of Medicine, Aurora, Colorado
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26
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Li J, Liu H, Raval MH, Wan J, Yengo CM, Liu W, Zhang M. Structure of the MORN4/Myo3a Tail Complex Reveals MORN Repeats as Protein Binding Modules. Structure 2019; 27:1366-1374.e3. [PMID: 31279628 DOI: 10.1016/j.str.2019.06.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/25/2019] [Accepted: 06/17/2019] [Indexed: 10/26/2022]
Abstract
Tandem repeats are basic building blocks for constructing proteins with diverse structures and functions. Compared with extensively studied α-helix-based tandem repeats such as ankyrin, tetratricopeptide, armadillo, and HEAT repeat proteins, relatively little is known about tandem repeat proteins formed by β hairpins. In this study, we discovered that the MORN repeats from MORN4 function as a protein binding module specifically recognizing a tail cargo binding region from Myo3a. The structure of the MORN4/Myo3a complex shows that MORN4 forms an extended single-layered β-sheet structure and uses a U-shaped groove to bind to the Myo3a tail with high affinity and specificity. Sequence and structural analyses further elucidated the unique sequence features for folding and target binding of MORN repeats. Our work establishes that the β-hairpin-based MORN repeats are protein-protein interaction modules.
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Affiliation(s)
- Jianchao Li
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Division of Cell, Developmental and Integrative Biology, School of Medicine, South China University of Technology, Guangzhou 510006, China
| | - Haiyang Liu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China
| | - Manmeet H Raval
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Jun Wan
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Wei Liu
- Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China.
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Shenzhen Key Laboratory for Neuronal Structural Biology, Biomedical Research Institute, Shenzhen Peking University-The Hong Kong University of Science and Technology Medical Center, Shenzhen 518036, China; Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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27
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Foster TJ. Surface Proteins of Staphylococcus aureus. Microbiol Spectr 2019; 7:10.1128/microbiolspec.gpp3-0046-2018. [PMID: 31267926 PMCID: PMC10957221 DOI: 10.1128/microbiolspec.gpp3-0046-2018] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Indexed: 12/20/2022] Open
Abstract
The surface of Staphylococcus aureus is decorated with over 20 proteins that are covalently anchored to peptidoglycan by the action of sortase A. These cell wall-anchored (CWA) proteins can be classified into several structural and functional groups. The largest is the MSCRAMM family, which is characterized by tandemly repeated IgG-like folded domains that bind peptide ligands by the dock lock latch mechanism or the collagen triple helix by the collagen hug. Several CWA proteins comprise modules that have different functions, and some individual domains can bind different ligands, sometimes by different mechanisms. For example, the N-terminus of the fibronectin binding proteins comprises an MSCRAMM domain which binds several ligands, while the C-terminus is composed of tandem fibronectin binding repeats. Surface proteins promote adhesion to host cells and tissue, including components of the extracellular matrix, contribute to biofilm formation by stimulating attachment to the host or indwelling medical devices followed by cell-cell accumulation via homophilic interactions between proteins on neighboring cells, help bacteria evade host innate immune responses, participate in iron acquisition from host hemoglobin, and trigger invasion of bacteria into cells that are not normally phagocytic. The study of genetically manipulated strains using animal infection models has shown that many CWA proteins contribute to pathogenesis. Fragments of CWA proteins have the potential to be used in multicomponent vaccines to prevent S. aureus infections.
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28
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Holehouse AS, Pappu RV. Collapse Transitions of Proteins and the Interplay Among Backbone, Sidechain, and Solvent Interactions. Annu Rev Biophys 2018; 47:19-39. [PMID: 29345991 PMCID: PMC10740066 DOI: 10.1146/annurev-biophys-070317-032838] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Proteins can collapse into compact globules or form expanded, solvent-accessible, coil-like conformations. Additionally, they can fold into well-defined three-dimensional structures or remain partially or entirely disordered. Recent discoveries have shown that the tendency for proteins to collapse or remain expanded is not intrinsically coupled to their ability to fold. These observations suggest that proteins do not have to form compact globules in aqueous solutions. They can be intrinsically disordered, collapsed, or expanded, and even form well-folded, elongated structures. This ability to decouple collapse from folding is determined by the sequence details of proteins. In this review, we highlight insights gleaned from studies over the past decade. Using a polymer physics framework, we explain how the interplay among sidechains, backbone units, and solvent determines the driving forces for collapsed versus expanded states in aqueous solvents.
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Affiliation(s)
- Alex S Holehouse
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in Saint Louis, Saint Louis, Missouri 63130, USA; ,
| | - Rohit V Pappu
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in Saint Louis, Saint Louis, Missouri 63130, USA; ,
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29
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Belyi Y, Rybolovlev I, Polyakov N, Chernikova A, Tabakova I, Gintsburg A. Staphylococcus Aureus Surface Protein G is An Immunodominant Protein and a Possible Target in An Anti-Biofilm Drug Development. Open Microbiol J 2018; 12:94-106. [PMID: 29785216 PMCID: PMC5944129 DOI: 10.2174/1874285801812010094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/08/2018] [Accepted: 04/11/2018] [Indexed: 12/18/2022] Open
Abstract
Background Staphylococcus aureus is a Gram-positive bacterium that causes severe illnesses in the human population. The capacity of S. aureus strains to form biofilms on biotic and abiotic surfaces creates serious problems for treatment of hospital infections and has stimulated efforts to develop new means of specific protection or immunotherapy. Material and Methods We found that rabbit serum raised against crude concentrated S. aureus liquid culture significantly decreased the development of staphylococcal biofilm in vitro. To discover the corresponding staphylococcal antigen, we used mass-spectrometry and molecular cloning and identified three major immunodominant proteins. They included α-haemolysin, serine proteinase SplB and S. aureus surface protein G, known as adhesin SasG. Results Although according to literature data, all these proteins represent virulence factors of S. aureus and play diverse and important roles in the pathogenesis of staphylococcal diseases, only SasG can be directly implicated into the biofilm formation because of its surface location on a staphylococcal cell. Indeed, rabbit serum directed against purified recombinant SasG, similar to serum against crude staphylococcal liquid culture, prevented the formation of a biofilm. Conclusion SasG can be considered as a target in an anti-biofilm drug development and a component of the vaccine or immunotherapeutic preparations directed against staphylococcal infections in humans.
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Affiliation(s)
- Yury Belyi
- Gamaleya Research Centre for Epidemiology and Microbiology, Moscow, Russia
| | - Ivan Rybolovlev
- Gamaleya Research Centre for Epidemiology and Microbiology, Moscow, Russia
| | - Nikita Polyakov
- Gamaleya Research Centre for Epidemiology and Microbiology, Moscow, Russia.,Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russia
| | | | - Irina Tabakova
- Gamaleya Research Centre for Epidemiology and Microbiology, Moscow, Russia
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30
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Yoshii Y, Okuda KI, Yamada S, Nagakura M, Sugimoto S, Nagano T, Okabe T, Kojima H, Iwamoto T, Kuwano K, Mizunoe Y. Norgestimate inhibits staphylococcal biofilm formation and resensitizes methicillin-resistant Staphylococcus aureus to β-lactam antibiotics. NPJ Biofilms Microbiomes 2017; 3:18. [PMID: 28758016 PMCID: PMC5522392 DOI: 10.1038/s41522-017-0026-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/28/2017] [Accepted: 06/30/2017] [Indexed: 02/06/2023] Open
Abstract
Formation of bacterial biofilms on medical devices can cause severe or fatal infectious diseases. In particular, biofilm-associated infections caused by methicillin-resistant Staphylococcus aureus are difficult to eradicate because the biofilm is strongly resistant to antibiotics and the host immune response. There is no effective treatment for biofilm-associated infectionss, except for surgical removal of contaminated medical devices followed by antibiotic therapy. Here we show that norgestimate, an acetylated progestin, effectively inhibits biofilm formation by staphylococcal strains, including methicillin-resistant S. aureus, without inhibiting their growth, decreasing the selective pressure for emergence of resistance. 17-Deacetyl norgestimate, a metabolite of norgestimate, shows much weaker inhibitory activity against staphylococcal biofilm formation, indicating that the acetyl group of norgestimate is important for its activity. Norgestimate inhibits staphylococcal biofilm formation by inhibiting production of polysaccharide intercellular adhesin and proteins in the extracellular matrix. Proteome analysis of S. aureus indicated that norgestimate represses the expression of the cell wall-anchored protein SasG, which promotes intercellular adhesion, and of the glycolytic enzyme enolase, which plays a secondary role in biofilm formation. Notably, norgestimate induces remarkable changes in cell wall morphology, characterized by increased thickness and abnormal rippled septa. Furthermore, norgestimate increases the expression level of penicillin binding protein 2 and resensitizes methicillin-resistant S. aureus to β-lactam antibiotics. These results suggest that norgestimate is a promising lead compound for the development of drugs to treat biofilm-associated infections, as well as for its ability to resensitize methicillin-resistant S. aureus to β-lactam antibiotics. A synthetic molecule related to the hormone progesterone might keep medical devices free of biofilms without promoting antibiotic resistance. Implanted devices that have become contaminated with biofilms generally must be surgically removed prior to treating the underlying infection with antibiotics. Ken-ichi Okuda and colleagues at The Jikei University School of Medicine in Tokyo, with co-workers elsewhere in Japan, found that the synthetic progesterone analog norgestimate inhibits biofilm formation without inhibiting bacterial growth. They regard this selective effect on biofilm formation as a significant advantage, as it reduces the risk of inducing resistance in the targeted bacteria. They demonstrated the effect using staphylococcal bacteria, including the problematic and highly dangerous methicillin-resistant Staphylococcus aureus (MRSA). The research also indicated that norgestimate can resensitize MRSA bacteria to some of the antibiotics they are resistant to.
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Affiliation(s)
- Yutaka Yoshii
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan.,Jikei Center for Biofilm Science and Technology, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan.,Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Ken-Ichi Okuda
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan.,Jikei Center for Biofilm Science and Technology, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Satomi Yamada
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Mari Nagakura
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Shinya Sugimoto
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan.,Jikei Center for Biofilm Science and Technology, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Tetsuo Nagano
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Takayoshi Okabe
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Hirotatsu Kojima
- Drug Discovery Initiative, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Takeo Iwamoto
- Division of Molecular Cell Biology, Core Research Facilities for Basic Science, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Kazuyoshi Kuwano
- Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
| | - Yoshimitsu Mizunoe
- Department of Bacteriology, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan.,Jikei Center for Biofilm Science and Technology, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461 Japan
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31
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Hiding in plain sight: immune evasion by the staphylococcal protein SdrE. Biochem J 2017; 474:1803-1806. [PMID: 28490660 DOI: 10.1042/bcj20170132] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 04/12/2017] [Accepted: 04/18/2017] [Indexed: 11/17/2022]
Abstract
The human immune system is responsible for identification and destruction of invader cells, such as the bacterial pathogen Staphylococcus aureus In response, S. aureus brings to the fight a large number of virulence factors, including several that allow it to evade the host immune response. The staphylococcal surface protein SdrE was recently reported to bind to complement Factor H, an important regulator of complement activation. Factor H attaches to the surface of host cells to inhibit complement activation and amplification, preventing the destruction of the host cell. SdrE binding to Factor H allows S. aureus to mimic a host cell and reduces bacterial killing by granulocytes. In a new study published in Biochemical Journal, Zhang et al. describe crystal structures of SdrE and its complex with the C-terminal portion of Factor H. The structure of SdrE and its interaction with the Factor H peptide closely resemble a family of surface proteins that recognize extracellular matrix components such as fibrinogen. However, unbound SdrE forms a novel 'Closed' conformation with an occluded peptide-binding groove. These structures reveal a fascinating mechanism for immune evasion and provide a potential avenue for the development of novel antimicrobial agents to target SdrE.
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32
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Back CR, Sztukowska MN, Till M, Lamont RJ, Jenkinson HF, Nobbs AH, Race PR. The Streptococcus gordonii Adhesin CshA Protein Binds Host Fibronectin via a Catch-Clamp Mechanism. J Biol Chem 2017; 292:1538-1549. [PMID: 27920201 PMCID: PMC5290933 DOI: 10.1074/jbc.m116.760975] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/01/2016] [Indexed: 11/06/2022] Open
Abstract
Adherence of bacteria to biotic or abiotic surfaces is a prerequisite for host colonization and represents an important step in microbial pathogenicity. This attachment is facilitated by bacterial adhesins at the cell surface. Because of their size and often elaborate multidomain architectures, these polypeptides represent challenging targets for detailed structural and functional characterization. The multifunctional fibrillar adhesin CshA, which mediates binding to both host molecules and other microorganisms, is an important determinant of colonization by Streptococcus gordonii, an oral commensal and opportunistic pathogen of animals and humans. CshA binds the high-molecular-weight glycoprotein fibronectin (Fn) via an N-terminal non-repetitive region, and this protein-protein interaction has been proposed to promote S. gordonii colonization at multiple sites within the host. However, the molecular details of how these two proteins interact have yet to be established. Here we present a structural description of the Fn binding N-terminal region of CshA, derived from a combination of X-ray crystallography, small angle X-ray scattering, and complementary biophysical methods. In vitro binding studies support a previously unreported two-state "catch-clamp" mechanism of Fn binding by CshA, in which the disordered N-terminal domain of CshA acts to "catch" Fn, via formation of a rapidly assembled but also readily dissociable pre-complex, enabling its neighboring ligand binding domain to tightly clamp the two polypeptides together. This study presents a new paradigm for target binding by a bacterial adhesin, the identification of which will inform future efforts toward the development of anti-adhesive agents that target S. gordonii and related streptococci.
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Affiliation(s)
- Catherine R Back
- From the School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom
| | - Maryta N Sztukowska
- the Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, Kentucky 40202; the Department of Dentistry, University of Information Technology and Management, 35-225 Rzeszow, Poland
| | - Marisa Till
- the School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom; the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom
| | - Richard J Lamont
- the Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, Kentucky 40202
| | - Howard F Jenkinson
- From the School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom
| | - Angela H Nobbs
- From the School of Oral and Dental Sciences, University of Bristol, Lower Maudlin Street, Bristol BS1 2LY, United Kingdom.
| | - Paul R Race
- the School of Biochemistry, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom; the BrisSynBio Synthetic Biology Research Centre, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, United Kingdom.
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33
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Paharik AE, Kotasinska M, Both A, Hoang TMN, Büttner H, Roy P, Fey PD, Horswill AR, Rohde H. The metalloprotease SepA governs processing of accumulation-associated protein and shapes intercellular adhesive surface properties in Staphylococcus epidermidis. Mol Microbiol 2017; 103:860-874. [PMID: 27997732 DOI: 10.1111/mmi.13594] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2016] [Indexed: 12/11/2022]
Abstract
The otherwise harmless skin inhabitant Staphylococcus epidermidis is a major cause of healthcare-associated medical device infections. The species' selective pathogenic potential depends on its production of surface adherent biofilms. The Cell wall-anchored protein Aap promotes biofilm formation in S. epidermidis, independently from the polysaccharide intercellular adhesin PIA. Aap requires proteolytic cleavage to act as an intercellular adhesin. Whether and which staphylococcal proteases account for Aap processing is yet unknown. Here, evidence is provided that in PIA-negative S. epidermidis 1457Δica, the metalloprotease SepA is required for Aap-dependent S. epidermidis biofilm formation in static and dynamic biofilm models. qRT-PCR and protease activity assays demonstrated that under standard growth conditions, sepA is repressed by the global regulator SarA. Inactivation of sarA increased SepA production, and in turn augmented biofilm formation. Genetic and biochemical analyses demonstrated that SepA-related induction of biofilm accumulation resulted from enhanced Aap processing. Studies using recombinant proteins demonstrated that SepA is able to cleave the A domain of Aap at residue 335 and between the A and B domains at residue 601. This study identifies the mechanism behind Aap-mediated biofilm maturation, and also demonstrates a novel role for a secreted staphylococcal protease as a requirement for the development of a biofilm.
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Affiliation(s)
- Alexandra E Paharik
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Marta Kotasinska
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Anna Both
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Tra-My N Hoang
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Henning Büttner
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Paroma Roy
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul D Fey
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Alexander R Horswill
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Holger Rohde
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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34
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Yarawsky AE, English LR, Whitten ST, Herr AB. The Proline/Glycine-Rich Region of the Biofilm Adhesion Protein Aap Forms an Extended Stalk that Resists Compaction. J Mol Biol 2017; 429:261-279. [PMID: 27890783 PMCID: PMC5363081 DOI: 10.1016/j.jmb.2016.11.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Revised: 11/22/2016] [Accepted: 11/22/2016] [Indexed: 12/11/2022]
Abstract
Staphylococcus epidermidis is one of the primary bacterial species responsible for healthcare-associated infections. The most significant virulence factor for S. epidermidis is its ability to form a biofilm, which renders the bacteria highly resistant to host immune responses and antibiotic action. Intercellular adhesion within the biofilm is mediated by the accumulation-associated protein (Aap), a cell wall-anchored protein that self-assembles in a zinc-dependent manner. The C-terminal portion of Aap contains a 135-aa-long, proline/glycine-rich region (PGR) that has not yet been characterized. The region contains a set of 18 nearly identical AEPGKP repeats. Analysis of the PGR using biophysical techniques demonstrated the region is a highly extended, intrinsically disordered polypeptide with unusually high polyproline type II helix propensity. In contrast to many intrinsically disordered polypeptides, there was a minimal temperature dependence of the global conformational state of PGR in solution as measured by analytical ultracentrifugation and dynamic light scattering. Furthermore, PGR was resistant to conformational collapse or α-helix formation upon the addition of the osmolyte trimethylamine N-oxide or the cosolvent 2,2,2-trifluoroethanol. Collectively, these results suggest PGR functions as a resilient, extended stalk that projects the rest of Aap outward from the bacterial cell wall, promoting intercellular adhesion between cells in the biofilm. This work sheds light on regions of low complexity often found near the attachment point of bacterial cell wall-anchored proteins.
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Affiliation(s)
- Alexander E Yarawsky
- Graduate Program in Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA; Division of Immunobiology and Center for Systems Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Lance R English
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Steven T Whitten
- Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Andrew B Herr
- Division of Immunobiology and Center for Systems Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
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35
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Shrestha L, Kayama S, Sasaki M, Kato F, Hisatsune J, Tsuruda K, Koizumi K, Tatsukawa N, Yu L, Takeda K, Sugai M. Inhibitory effects of antibiofilm compound 1 against Staphylococcus aureus biofilms. Microbiol Immunol 2017; 60:148-59. [PMID: 26786482 DOI: 10.1111/1348-0421.12359] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/04/2016] [Accepted: 01/12/2016] [Indexed: 01/01/2023]
Abstract
A novel benzimidazole molecule that was identified in a small-molecule screen and is known as antibiofilm compound 1 (ABC-1) has been found to prevent bacterial biofilm formation by multiple bacterial pathogens, including Staphylococcus aureus, without affecting bacterial growth. Here, the biofilm inhibiting ability of 156 μM ABC-1 was tested in various biofilm-forming strains of S. aureus. It was demonstrated that ABC-1 inhibits biofilm formation by these strains at micromolar concentrations regardless of the strains' dependence on Polysaccharide Intercellular Adhesin (PIA), cell wall-associated protein dependent or cell wall- associated extracellular DNA (eDNA). Of note, ABC-1 treatment primarily inhibited Protein A (SpA) expression in all strains tested. spa gene disruption showed decreased biofilm formation; however, the mutants still produced more biofilm than ABC-1 treated strains, implying that ABC-1 affects not only SpA but also other factors. Indeed, ABC-1 also attenuated the accumulation of PIA and eDNA on cell surface. Our results suggest that ABC-1 has pleotropic effects on several biofilm components and thus inhibits biofilm formation by S. aureus.
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Affiliation(s)
- Looniva Shrestha
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences
| | - Shizuo Kayama
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences.,Project Research Center for Nosocomial Infectious Disease, Hiroshima University
| | - Michiko Sasaki
- Department of Synthetic Organic Chemistry, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi Minami-ku Hiroshima 734-8551, Japan
| | - Fuminori Kato
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences.,Project Research Center for Nosocomial Infectious Disease, Hiroshima University
| | - Junzo Hisatsune
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences.,Project Research Center for Nosocomial Infectious Disease, Hiroshima University
| | - Keiko Tsuruda
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences
| | - Kazuhisa Koizumi
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences.,Project Research Center for Nosocomial Infectious Disease, Hiroshima University
| | - Nobuyuki Tatsukawa
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences
| | - Liansheng Yu
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences
| | - Kei Takeda
- Department of Synthetic Organic Chemistry, Hiroshima University Graduate School of Biomedical Sciences, 1-2-3 Kasumi Minami-ku Hiroshima 734-8551, Japan
| | - Motoyuki Sugai
- Department of Bacteriology, Hiroshima University Graduate School of Biomedical Sciences.,Project Research Center for Nosocomial Infectious Disease, Hiroshima University
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36
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Functional consequences of B-repeat sequence variation in the staphylococcal biofilm protein Aap: deciphering the assembly code. Biochem J 2016; 474:427-443. [PMID: 27872164 DOI: 10.1042/bcj20160675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/07/2016] [Accepted: 11/21/2016] [Indexed: 01/27/2023]
Abstract
Staphylococcus epidermidis is an opportunistic pathogen that can form robust biofilms that render the bacteria resistant to antibiotic action and immune responses. Intercellular adhesion in S. epidermidis biofilms is mediated by the cell wall-associated accumulation-associated protein (Aap), via zinc-mediated self-assembly of its B-repeat region. This region contains up to 17 nearly identical sequence repeats, with each repeat assumed to be functionally equivalent. However, Aap B-repeats exist as two subtypes, defined by a cluster of consensus or variant amino acids. These variable residues are positioned near the zinc-binding (and dimerization) site and the stability determinant for the B-repeat fold. We have characterized four B-repeat constructs to assess the functional relevance of the two Aap B-repeat subtypes. Analytical ultracentrifugation experiments demonstrated that constructs with the variant sequence show reduced or absent Zn2+-induced dimerization. Likewise, circular dichroism thermal denaturation experiments showed that the variant sequence could significantly stabilize the fold, depending on its location within the construct. Crystal structures of three of the constructs revealed that the side chains from the variant sequence form an extensive bonding network that can stabilize the fold. Furthermore, altered distribution of charged residues between consensus and variant sequences changes the electrostatic potential in the vicinity of the Zn2+-binding site, providing a mechanistic explanation for the loss of zinc-induced dimerization in the variant constructs. These data suggest an assembly code that defines preferred oligomerization modes of the B-repeat region of Aap and a slip-grip model for initial contact followed by firm intercellular adhesion during biofilm formation.
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Abstract
Many human proteins contain intrinsically disordered regions, and disorder in these proteins can be fundamental to their function-for example, facilitating transient but specific binding, promoting allostery, or allowing efficient posttranslational modification. SasG, a multidomain protein implicated in host colonization and biofilm formation in Staphylococcus aureus, provides another example of how disorder can play an important role. Approximately one-half of the domains in the extracellular repetitive region of SasG are intrinsically unfolded in isolation, but these E domains fold in the context of their neighboring folded G5 domains. We have previously shown that the intrinsic disorder of the E domains mediates long-range cooperativity between nonneighboring G5 domains, allowing SasG to form a long, rod-like, mechanically strong structure. Here, we show that the disorder of the E domains coupled with the remarkable stability of the interdomain interface result in cooperative folding kinetics across long distances. Formation of a small structural nucleus at one end of the molecule results in rapid structure formation over a distance of 10 nm, which is likely to be important for the maintenance of the structural integrity of SasG. Moreover, if this normal folding nucleus is disrupted by mutation, the interdomain interface is sufficiently stable to drive the folding of adjacent E and G5 domains along a parallel folding pathway, thus maintaining cooperative folding.
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The BR domain of PsrP interacts with extracellular DNA to promote bacterial aggregation; structural insights into pneumococcal biofilm formation. Sci Rep 2016; 6:32371. [PMID: 27582320 PMCID: PMC5007671 DOI: 10.1038/srep32371] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 08/05/2016] [Indexed: 12/21/2022] Open
Abstract
The major human pathogen Streptococcus pneumoniae is a leading cause of disease and death worldwide. Pneumococcal biofilm formation within the nasopharynx leads to long-term colonization and persistence within the host. We have previously demonstrated that the capsular surface-associated pneumococcal serine rich repeat protein (PsrP), key factor for biofilm formation, binds to keratin-10 (KRT10) through its microbial surface component recognizing adhesive matrix molecule (MSCRAMM)-related globular binding region domain (BR187–385). Here, we show that BR187–385 also binds to DNA, as demonstrated by electrophoretic mobility shift assays and size exclusion chromatography. Further, heterologous expression of BR187–378 or the longer BR120–378 construct on the surface of a Gram-positive model host bacterium resulted in the formation of cellular aggregates that was significantly enhanced in the presence of DNA. Crystal structure analyses revealed the formation of BR187–385 homo-dimers via an intermolecular β-sheet, resulting in a positively charged concave surface, shaped to accommodate the acidic helical DNA structure. Furthermore, small angle X-ray scattering and circular dichroism studies indicate that the aggregate-enhancing N-terminal region of BR120–166 adopts an extended, non-globular structure. Altogether, our results suggest that PsrP adheres to extracellular DNA in the biofilm matrix and thus promotes pneumococcal biofilm formation.
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Abstract
Centrioles are evolutionarily conserved cylindrical cell organelles with characteristic radial symmetry. Despite their considerable size (400 nm × 200 nm, in humans), genetic studies suggest that relatively few protein components are involved in their assembly. We recently characterized the molecular architecture of the centrosomal P4.1-associated protein (CPAP), which is crucial for controlling the centriolar cylinder length. Here, we review the remarkable architecture of the C-terminal domain of CPAP, termed the G-box, which comprises a single, entirely solvent exposed, antiparallel β-sheet. Molecular dynamics simulations support the stability of the G-box domain even in the face of truncations or amino acid substitutions. The similarity of the G-box domain to amyloids (or amyloid precursors) is strengthened by its oligomeric arrangement to form continuous fibrils. G-box fibrils were observed in crystals as well as in solution and are also supported by simulations. We conclude that the G-box domain may well represent the best analogue currently available for studies of exposed β-sheets, unencumbered by additional structural elements or severe aggregations problems.
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Two repetitive, biofilm-forming proteins from Staphylococci: from disorder to extension. Biochem Soc Trans 2016; 43:861-6. [PMID: 26517895 DOI: 10.1042/bst20150088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Staphylococcus aureus and Staphylococcus epidermidis are an important cause of medical device-related infections that are difficult to treat with antibiotics. Biofilms, in which bacteria are embedded in a bacterially-produced exopolymeric matrix, form on the surface of the implanted medical device. Our understanding of the molecular mechanisms underlying the initial surface attachment and subsequent intercellular interactions as the biofilm matures is improving. Biofilm accumulation can be mediated by a partially deacetylated form of poly-N-acetylglucosamine (PNAG) but, more recently, the role of bacterial surface proteins is being recognized. Here we describe the structure and function of two S. aureus cell surface proteins, FnBPA and SasG, implicated in host interactions and biofilm accumulation. These multifunctional proteins employ intrinsic disorder for distinct molecular outcomes. In the case of FnBPA, disorder generates adhesive arrays that bind fibronectin (Fn); in the case of SasG, disorder is, counterintuitively, used to maintain a strong extended fold.
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Formosa-Dague C, Feuillie C, Beaussart A, Derclaye S, Kucharíková S, Lasa I, Van Dijck P, Dufrêne YF. Sticky Matrix: Adhesion Mechanism of the Staphylococcal Polysaccharide Intercellular Adhesin. ACS NANO 2016; 10:3443-3452. [PMID: 26908275 DOI: 10.1021/acsnano.5b07515] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The development of bacterial biofilms on surfaces leads to hospital-acquired infections that are difficult to fight. In Staphylococci, the cationic polysaccharide intercellular adhesin (PIA) forms an extracellular matrix that connects the cells together during biofilm formation, but the molecular forces involved are unknown. Here, we use advanced force nanoscopy techniques to unravel the mechanism of PIA-mediated adhesion in a clinically relevant methicillin-resistant Staphylococcus aureus (MRSA) strain. Nanoscale multiparametric imaging of the structure, adhesion, and elasticity of bacteria expressing PIA shows that the cells are surrounded by a soft and adhesive matrix of extracellular polymers. Cell surface softness and adhesion are dramatically reduced in mutant cells deficient for the synthesis of PIA or under unfavorable growth conditions. Single-cell force spectroscopy demonstrates that PIA promotes cell-cell adhesion via the multivalent electrostatic interaction with polyanionic teichoic acids on the S. aureus cell surface. This binding mechanism rationalizes, at the nanoscale, the well-known ability of PIA to strengthen intercellular adhesion in staphylococcal biofilms. Force nanoscopy offers promising prospects for understanding the fundamental forces in antibiotic-resistant biofilms and for designing anti-adhesion compounds targeting matrix polymers.
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Affiliation(s)
- Cécile Formosa-Dague
- Institute of Life Sciences, Université catholique de Louvain , Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
| | - Cécile Feuillie
- Institute of Life Sciences, Université catholique de Louvain , Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
| | - Audrey Beaussart
- Institute of Life Sciences, Université catholique de Louvain , Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
| | - Sylvie Derclaye
- Institute of Life Sciences, Université catholique de Louvain , Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
| | - Soňa Kucharíková
- Department of Molecular Microbiology, VIB,, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3000 Leuven, Belgium
| | - Iñigo Lasa
- Group of Microbial Communities and Disease, Navarrabiomed-FMS, UPNA, IdiSNA, 31008 Navarra, Spain
| | - Patrick Van Dijck
- Department of Molecular Microbiology, VIB,, KU Leuven, 3000 Leuven, Belgium
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, 3000 Leuven, Belgium
| | - Yves F Dufrêne
- Institute of Life Sciences, Université catholique de Louvain , Croix du Sud, 4-5, bte L7.07.06., B-1348 Louvain-la-Neuve, Belgium
- Walloon Excellence in Life sciences and Biotechnology (WELBIO), 1300 Wavre, Belgium
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Arora S, Uhlemann AC, Lowy FD, Hook M. A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species. Front Microbiol 2016; 7:540. [PMID: 27199900 PMCID: PMC4850167 DOI: 10.3389/fmicb.2016.00540] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022] Open
Abstract
Coagulase negative staphylococci (CoNS) are important opportunistic pathogens. Staphylococcus epidermidis, a coagulase negative staphylococcus, is the third leading cause of nosocomial infections in the US. Surface proteins like Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are major virulence factors of pathogenic gram positive bacteria. Here, we identified a new chimeric protein in S. epidermidis, that we call SesJ. SesJ represents a prototype of a new subfamily of MSCRAMMs. Structural predictions show that SesJ has structural features characteristic of a MSCRAMM along with a N-terminal repeat region and an aspartic acid containing C-terminal repeat region, features that have not been previously observed in staphylococcal MSCRAMMs but have been found in other surface proteins from gram positive bacteria. We identified and analyzed structural homologs of SesJ in three other CoNS. These homologs of SesJ have an identical structural organization but varying sequence identities within the domains. Using flow cytometry, we also show that SesJ is expressed constitutively on the surface of a representative S. epidermidis strain, from early exponential to stationary growth phase. Thus, SesJ is positioned to interact with protein targets in the environment and plays a role in S. epidermidis virulence.
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Affiliation(s)
- Srishtee Arora
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, HoustonTX, USA
| | - Anne-Catrin Uhlemann
- Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University in the City of New York, New YorkNY, USA
| | - Franklin D. Lowy
- Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University in the City of New York, New YorkNY, USA
| | - Magnus Hook
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, HoustonTX, USA
- *Correspondence: Magnus Hook,
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Zinc-dependent mechanical properties of Staphylococcus aureus biofilm-forming surface protein SasG. Proc Natl Acad Sci U S A 2015; 113:410-5. [PMID: 26715750 DOI: 10.1073/pnas.1519265113] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Staphylococcus aureus surface protein SasG promotes cell-cell adhesion during the accumulation phase of biofilm formation, but the molecular basis of this interaction remains poorly understood. Here, we unravel the mechanical properties of SasG on the surface of living bacteria, that is, in its native cellular environment. Nanoscale multiparametric imaging of living bacteria reveals that Zn(2+) strongly increases cell wall rigidity and activates the adhesive function of SasG. Single-cell force measurements show that SasG mediates cell-cell adhesion via specific Zn(2+)-dependent homophilic bonds between β-sheet-rich G5-E domains on neighboring cells. The force required to unfold individual domains is remarkably strong, up to ∼500 pN, thus explaining how SasG can withstand physiological shear forces. We also observe that SasG forms homophilic bonds with the structurally related accumulation-associated protein of Staphylococcus epidermidis, suggesting the possibility of multispecies biofilms during host colonization and infection. Collectively, our findings support a model in which zinc plays a dual role in activating cell-cell adhesion: adsorption of zinc ions to the bacterial cell surface increases cell wall cohesion and favors the projection of elongated SasG proteins away from the cell surface, thereby enabling zinc-dependent homophilic bonds between opposing cells. This work demonstrates an unexpected relationship between mechanics and adhesion in a staphylococcal surface protein, which may represent a general mechanism among bacterial pathogens for activating cell association.
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Li H, Xin H, Li SFY. Multiplex PMA-qPCR Assay with Internal Amplification Control for Simultaneous Detection of Viable Legionella pneumophila, Salmonella typhimurium, and Staphylococcus aureus in Environmental Waters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:14249-56. [PMID: 26512952 DOI: 10.1021/acs.est.5b03583] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Pathogenic microorganisms are responsible for many infectious diseases, and pathogen monitoring is important and necessary for water quality control. This study for the first time explored a multiplex quantitative real-time PCR (qPCR) technique combined with propidium monoazide (PMA) to simultaneously detect viable Legionella pneumophila, Salmonella typhimurium, and Staphylococcus aureus in one reaction from water samples. Sodium lauroyl sarcosinate (sarkosyl) was applied to enhance the dead bacterial permeability of PMA. The sensitivity of the multiplex PMA-qPCR assay achieved two colony-forming units (CFU) per reaction for L. pneumophila and three CFU per reaction for S. typhimurium and S. aureus. No PCR products were amplified from all nontarget control samples. Significantly, with comparable specificity and sensitivity, this newly invented multiplex PMA-qPCR assay took a much shorter time than did conventional culture assays when testing water samples with spiked bacteria and simulated environmental water treatment. The viable multiplex PMA-qPCR assay was further successfully applied to pathogen detection from rivers, canals, and tap water samples after simple water pretreatment.
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Affiliation(s)
- Haiyan Li
- Department of Chemistry, Faculty of Science, National University of Singapore , 3 Science Drive 3, Singapore 117543
| | - Hongyi Xin
- Bioinformatics Institute, Agency for Science, Technology and Research , 30 Biopolis Street, Singapore 138671
| | - Sam Fong Yau Li
- Department of Chemistry, Faculty of Science, National University of Singapore , 3 Science Drive 3, Singapore 117543
- NUS Environmental Research Institute, National University of Singapore , 5A Engineering Drive 1, Singapore 117411
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Self-generated covalent cross-links in the cell-surface adhesins of Gram-positive bacteria. Biochem Soc Trans 2015; 43:787-94. [DOI: 10.1042/bst20150066] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The ability of bacteria to adhere to other cells or to surfaces depends on long, thin adhesive structures that are anchored to their cell walls. These structures include extended protein oligomers known as pili and single, multi-domain polypeptides, mostly based on multiple tandem Ig-like domains. Recent structural studies have revealed the widespread presence of covalent cross-links, not previously seen within proteins, which stabilize these domains. The cross-links discovered so far are either isopeptide bonds that link lysine side chains to the side chains of asparagine or aspartic acid residues or ester bonds between threonine and glutamine side chains. These bonds appear to be formed by spontaneous intramolecular reactions as the proteins fold and are strategically placed so as to impart considerable mechanical strength.
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Gruszka DT, Whelan F, Farrance OE, Fung HKH, Paci E, Jeffries CM, Svergun DI, Baldock C, Baumann CG, Brockwell DJ, Potts JR, Clarke J. Cooperative folding of intrinsically disordered domains drives assembly of a strong elongated protein. Nat Commun 2015; 6:7271. [PMID: 26027519 PMCID: PMC4458895 DOI: 10.1038/ncomms8271] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/23/2015] [Indexed: 11/09/2022] Open
Abstract
Bacteria exploit surface proteins to adhere to other bacteria, surfaces and host cells. Such proteins need to project away from the bacterial surface and resist significant mechanical forces. SasG is a protein that forms extended fibrils on the surface of Staphylococcus aureus and promotes host adherence and biofilm formation. Here we show that although monomeric and lacking covalent cross-links, SasG maintains a highly extended conformation in solution. This extension is mediated through obligate folding cooperativity of the intrinsically disordered E domains that couple non-adjacent G5 domains thermodynamically, forming interfaces that are more stable than the domains themselves. Thus, counterintuitively, the elongation of the protein appears to be dependent on the inherent instability of its domains. The remarkable mechanical strength of SasG arises from tandemly arrayed 'clamp' motifs within the folded domains. Our findings reveal an elegant minimal solution for the assembly of monomeric mechano-resistant tethers of variable length.
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Affiliation(s)
- Dominika T. Gruszka
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Fiona Whelan
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Oliver E. Farrance
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Herman K. H. Fung
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Emanuele Paci
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Cy M. Jeffries
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22603 Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22603 Hamburg, Germany
| | - Clair Baldock
- Faculty of Life Sciences, Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Michael Smith Building, Greater Manchester M13 9PT, UK
| | | | - David J. Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Jennifer R. Potts
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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Prakash A, Bateman A. Domain atrophy creates rare cases of functional partial protein domains. Genome Biol 2015; 16:88. [PMID: 25924720 PMCID: PMC4432964 DOI: 10.1186/s13059-015-0655-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/15/2015] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Protein domains display a range of structural diversity, with numerous additions and deletions of secondary structural elements between related domains. We have observed a small number of cases of surprising large-scale deletions of core elements of structural domains. We propose a new concept called domain atrophy, where protein domains lose a significant number of core structural elements. RESULTS Here, we implement a new pipeline to systematically identify new cases of domain atrophy across all known protein sequences. The output of this pipeline was carefully checked by hand, which filtered out partial domain instances that were unlikely to represent true domain atrophy due to misannotations or un-annotated sequence fragments. We identify 75 cases of domain atrophy, of which eight cases are found in a three-dimensional protein structure and 67 cases have been inferred based on mapping to a known homologous structure. Domains with structural variations include ancient folds such as the TIM-barrel and Rossmann folds. Most of these domains are observed to show structural loss that does not affect their functional sites. CONCLUSION Our analysis has significantly increased the known cases of domain atrophy. We discuss specific instances of domain atrophy and see that there has often been a compensatory mechanism that helps to maintain the stability of the partial domain. Our study indicates that although domain atrophy is an extremely rare phenomenon, protein domains under certain circumstances can tolerate extreme mutations giving rise to partial, but functional, domains.
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Affiliation(s)
- Ananth Prakash
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK.
| | - Alex Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK.
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Hobley L, Harkins C, MacPhee CE, Stanley-Wall NR. Giving structure to the biofilm matrix: an overview of individual strategies and emerging common themes. FEMS Microbiol Rev 2015; 39:649-69. [PMID: 25907113 PMCID: PMC4551309 DOI: 10.1093/femsre/fuv015] [Citation(s) in RCA: 331] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/09/2015] [Indexed: 01/24/2023] Open
Abstract
Biofilms are communities of microbial cells that underpin diverse processes including sewage bioremediation, plant growth promotion, chronic infections and industrial biofouling. The cells resident in the biofilm are encased within a self-produced exopolymeric matrix that commonly comprises lipids, proteins that frequently exhibit amyloid-like properties, eDNA and exopolysaccharides. This matrix fulfils a variety of functions for the community, from providing structural rigidity and protection from the external environment to controlling gene regulation and nutrient adsorption. Critical to the development of novel strategies to control biofilm infections, or the capability to capitalize on the power of biofilm formation for industrial and biotechnological uses, is an in-depth knowledge of the biofilm matrix. This is with respect to the structure of the individual components, the nature of the interactions between the molecules and the three-dimensional spatial organization. We highlight recent advances in the understanding of the structural and functional role that carbohydrates and proteins play within the biofilm matrix to provide three-dimensional architectural integrity and functionality to the biofilm community. We highlight, where relevant, experimental techniques that are allowing the boundaries of our understanding of the biofilm matrix to be extended using Escherichia coli, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis as exemplars. Examining the structure and function of the biofilm extracellular matrix.
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Affiliation(s)
- Laura Hobley
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Catriona Harkins
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Cait E MacPhee
- James Clerk Maxwell Building, School of Physics, University of Edinburgh, Edinburgh EH9 3JZ, UK
| | - Nicola R Stanley-Wall
- Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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Decker R, Burdelski C, Zobiak M, Büttner H, Franke G, Christner M, Saß K, Zobiak B, Henke HA, Horswill AR, Bischoff M, Bur S, Hartmann T, Schaeffer CR, Fey PD, Rohde H. An 18 kDa scaffold protein is critical for Staphylococcus epidermidis biofilm formation. PLoS Pathog 2015; 11:e1004735. [PMID: 25799153 PMCID: PMC4370877 DOI: 10.1371/journal.ppat.1004735] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 02/06/2015] [Indexed: 12/15/2022] Open
Abstract
Virulence of the nosocomial pathogen Staphylococcus epidermidis is crucially linked to formation of adherent biofilms on artificial surfaces. Biofilm assembly is significantly fostered by production of a bacteria derived extracellular matrix. However, the matrix composition, spatial organization, and relevance of specific molecular interactions for integration of bacterial cells into the multilayered biofilm community are not fully understood. Here we report on the function of novel 18 kDa Small basic protein (Sbp) that was isolated from S. epidermidis biofilm matrix preparations by an affinity chromatographic approach. Sbp accumulates within the biofilm matrix, being preferentially deposited at the biofilm–substratum interface. Analysis of Sbp-negative S. epidermidis mutants demonstrated the importance of Sbp for sustained colonization of abiotic surfaces, but also epithelial cells. In addition, Sbp promotes assembly of S. epidermidis cell aggregates and establishment of multilayered biofilms by influencing polysaccharide intercellular-adhesin (PIA) and accumulation associated protein (Aap) mediated intercellular aggregation. While inactivation of Sbp indirectly resulted in reduced PIA-synthesis and biofilm formation, Sbp serves as an essential ligand during Aap domain-B mediated biofilm accumulation. Our data support the conclusion that Sbp serves as an S. epidermidis biofilm scaffold protein that significantly contributes to key steps of surface colonization. Sbp-negative S. epidermidis mutants showed no attenuated virulence in a mouse catheter infection model. Nevertheless, the high prevalence of sbp in commensal and invasive S. epidermidis populations suggests that Sbp plays a significant role as a co-factor during both multi-factorial commensal colonization and infection of artificial surfaces. Biofilm formation is a key phenotype allowing the otherwise harmless skin commensal S. epidermidis to establish chronic implant-associated infections, affecting millions of patients worldwide. S. epidermidis biofilm assembly relies on the production of an extracellular matrix that serves as glue to stabilize the multilayered bacterial architecture. Here we identified novel 18 kDa Small basic protein (Sbp) as a key component of the extracellular matrix that promotes pivotal steps of bacterial biofilm formation in vitro. Importantly, Sbp is deposited specifically at the interface between biofilm and substrate, as well as in larger humps interspersed within the bacterial cell architecture, thereby forming a proteinaceous biofilm scaffold. This localization enables Sbp to foster stable S. epidermidis interactions with an artificial surface and also contributes to S. epidermidis cell aggregation mechanisms, i.e., polysaccharide intercellular adhesin (PIA) and accumulation associated protein (Aap). In fact, by demonstrating direct Sbp-Aap interactions we provide the first evidence supporting the idea that specific molecular interactions between S. epidermidis and matrix components are involved in S. epidermidis biofilm accumulation. In conclusion, we here show that Sbp promotes key phenotypic features important for S. epidermidis to evolve as an opportunistic pathogen.
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Affiliation(s)
- Rahel Decker
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Christoph Burdelski
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Melanie Zobiak
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Henning Büttner
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Gefion Franke
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Martin Christner
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Katharina Saß
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Bernd Zobiak
- UKE Microscopy Imaging Facility, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Hanae A. Henke
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
| | - Alexander R. Horswill
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Markus Bischoff
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum des Saarlandes, Homburg, Germany
| | - Stephanie Bur
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum des Saarlandes, Homburg, Germany
| | - Torsten Hartmann
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinikum des Saarlandes, Homburg, Germany
| | - Carolyn R. Schaeffer
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Paul D. Fey
- Department of Pathology and Microbiology, Center for Staphylococcal Research, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Holger Rohde
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Hamburg, Germany
- * E-mail:
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Büttner H, Mack D, Rohde H. Structural basis of Staphylococcus epidermidis biofilm formation: mechanisms and molecular interactions. Front Cell Infect Microbiol 2015; 5:14. [PMID: 25741476 PMCID: PMC4330918 DOI: 10.3389/fcimb.2015.00014] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/26/2015] [Indexed: 02/01/2023] Open
Abstract
Staphylococcus epidermidis is a usually harmless commensal bacterium highly abundant on the human skin. Under defined predisposing conditions, most importantly implantation of a medical device, S. epidermidis, however, can switch from a colonizing to an invasive life style. The emergence of S. epidermidis as an opportunistic pathogen is closely linked to the biofilm forming capability of the species. During the past decades, tremendous advance regarding our understanding of molecular mechanisms contributing to surface colonization has been made, and detailed information is available for several factors active during the primary attachment, accumulative or dispersal phase of biofilm formation. A picture evolved in which distinct factors, though appearing to be redundantly organized, take over specific and exclusive functions during biofilm development. In this review, these mechanisms are described in molecular detail, with a highlight on recent insights into multi-functional S. epidermidis cell surface proteins contributing to surface adherence and intercellular adhesion. The integration of distinct biofilm-promoting factors into regulatory networks is summarized, with an emphasis on mechanism that could allow S. epidermidis to flexibly adapt to changing environmental conditions present during colonizing or invasive life-styles.
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Affiliation(s)
- Henning Büttner
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf Hamburg, Germany
| | - Dietrich Mack
- Mikrobiologie/Infektiologie, Bioscientia Labor Ingelheim, Institut für Medizinische Diagnostik GmbH Ingelheim, Germany
| | - Holger Rohde
- Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf Hamburg, Germany
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