1
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Zhu R, Stone T, Wang Y. The role of shear rates on amyloid formation from biofilm peptide phenol-soluble modulins. Biophys J 2024; 123:1106-1115. [PMID: 38549371 PMCID: PMC11079943 DOI: 10.1016/j.bpj.2024.03.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 01/28/2024] [Accepted: 03/26/2024] [Indexed: 04/15/2024] Open
Abstract
Biofilms, microbial communities enclosed in the self-produced extracellular matrix, have a significant impact on human health, environment, and industry. The pathogen Staphylococcus aureus (S. aureus) is recognized as one of the most frequent causes of biofilm-related infections. Phenol-soluble modulins (PSMs) serve as a crucial component, fortifying S. aureus biofilm matrix through self-assembly into amyloid fibrils, which enhances S. aureus colonization and resistance to antibiotics. However, the role of shear rate, one of the critical physiological factors within blood vessels, on the formation of PSM amyloids remains poorly understood. In this work, using a combination of thioflavin T fluorescence kinetic studies, circular dichroism spectrometry, and electron microscopy, we demonstrated that shear rates ranging from 150 to 300 s-1 accelerate fibrillation of PSMα1, α3, and α4 into amyloids, resulting in elongated amyloid structures. Furthermore, PSMα1, α3, and α4 predominantly self-assembled into amyloid fibers with a cross-α structure under shear conditions, deviating from the typical β-sheet configuration of PSM amyloids. These findings imply the role of shear rates within the bloodstream on enhancing PSM self-assembly that is associated with S. aureus biofilm formation.
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Affiliation(s)
- Runyao Zhu
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana
| | - Trevor Stone
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana; Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia
| | - Yichun Wang
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana.
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2
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Master NG, Markande AR. Importance of microbial amphiphiles: interaction potential of biosurfactants, amyloids, and other exo-polymeric-substances. World J Microbiol Biotechnol 2023; 39:320. [PMID: 37747579 DOI: 10.1007/s11274-023-03751-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 09/04/2023] [Indexed: 09/26/2023]
Abstract
Microorganisms produce a diverse group of biomolecules having amphipathic nature (amphiphiles). Microbial amphiphiles, including amyloids, bio-surfactants, and other exo-polymeric substances, play a crucial role in various biological processes and have gained significant attention recently. Although diverse in biochemical composition, these amphiphiles have been reported for common microbial traits like biofilm formation and pathogenicity due to their ability to act as surface active agents with active interfacial properties essential for microbes to grow in various niches. This enables microbes to reduce surface tension, emulsification, dispersion, and attachment at the interface. In this report, the ecological importance and biotechnological usage of important amphiphiles have been discussed. The low molecular weight amphiphiles like biosurfactants, siderophores, and peptides showing helical and antimicrobial activities have been extensively reported for their ability to work as quorum-sensing mediators. While high molecular weight amphiphiles make up amyloid fibers, exopolysaccharides, liposomes, or magnetosomes have been shown to have a significant influence in deciding microbial physiology and survival. In this report, we have discussed the functional similarities and biochemical variations of several amphipathic biomolecules produced by microbes, and the present report shows these amphiphiles showing polyphyletic and ecophysiological groups of microorganisms and hence can `be replaced in biotechnological applications depending on the compatibility of the processes.
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Affiliation(s)
- Nishita G Master
- Department of Biological Sciences, P.D. Patel Institute of Applied Sciences (PDPIAS), Charotar University of Science and Technology (CHARUSAT), Changa, Anand, Gujarat, 388421, India
| | - Anoop R Markande
- Department of Biological Sciences, P.D. Patel Institute of Applied Sciences (PDPIAS), Charotar University of Science and Technology (CHARUSAT), Changa, Anand, Gujarat, 388421, India.
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3
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Rayan B, Barnea E, Khokhlov A, Upcher A, Landau M. Differential fibril morphologies and thermostability determine functional roles of Staphylococcus aureus PSMα1 and PSMα3. Front Mol Biosci 2023; 10:1184785. [PMID: 37469708 PMCID: PMC10353841 DOI: 10.3389/fmolb.2023.1184785] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023] Open
Abstract
Phenol-soluble modulins (PSMs) are virulent peptides secreted by staphylococci that undergo self-assembly into amyloid fibrils. This study focuses on Staphylococcus aureus PSMα1 and PSMα3, which share homologous sequences but exhibit distinct amyloid fibril structures. Upon subjecting PSMα1 to an 80°C heat shock, it fibrillates into cross-β structures, resulting in the loss of cytotoxic activity. Conversely, PSMα3 cross-α fibrils undergo reversible disaggregation upon heat shock, leading to the recovery of cytotoxicity. The differential thermostability probably arises from the presence of hydrogen bonds along the β-strands within the β-sheets of the cross-β fibrils. We propose that the breakdown of PSMα3 fibrils into soluble species, potentially co-aggregating with membrane lipids, is crucial for its toxic process and enables the reversible modulation of its biological activity under stress conditions. In contrast, the formation of robust and irreversible cross-β fibrils by PSMα1 corresponds to its role in biofilm stability. These findings emphasize how the unique fibril morphologies and thermostability of PSMα1 and PSMα3 shape their functional roles in various environments of S. aureus.
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Affiliation(s)
- Bader Rayan
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Eilon Barnea
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Alexander Khokhlov
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Alexander Upcher
- Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer-Sheva, Israel
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
- Centre for Structural Systems Biology (CSSB), Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
- The Center for Experimental Medicine, Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany
- European Molecular Biology Laboratory (EMBL), Hamburg, Germany
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4
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Prosswimmer T, Daggett V. The role of α-sheet structure in amyloidogenesis: characterization and implications. Open Biol 2022; 12:220261. [PMID: 36416010 PMCID: PMC9682440 DOI: 10.1098/rsob.220261] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Amyloid diseases are linked to protein misfolding whereby the amyloidogenic protein undergoes a conformational change, aggregates and eventually forms amyloid fibrils. While the amyloid fibrils and plaques are hallmarks of these diseases, they typically form late in the disease process and do not correlate with disease. Instead, there is growing evidence that smaller, soluble toxic oligomers form prior and appear to be early triggers of the molecular pathology underlying these diseases. Nearly 20 years ago, we proposed the α-sheet hypothesis after discovering that the early conformational changes observed during atomistic molecular dynamics simulations involve the formation of a non-standard protein structure, α-sheet. Furthermore, we proposed that toxic oligomers contain α-sheet structure and that preferentially targeting this structure could neutralize the toxicity, prevent further aggregation and serve as the basis for early detection of disease. Here, we present the origin of the α-sheet hypothesis and describe α-sheet structure and the corresponding mechanisms of conversion. We discuss experimental studies demonstrating that both mammalian and bacterial amyloid systems form α-sheet oligomers before converting to conventional β-sheet fibrils. Furthermore, we show that the process can be inhibited with de novo designed α-sheet peptides complementary to the structure in the toxic oligomers.
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Affiliation(s)
- Tatum Prosswimmer
- Molecular Engineering Program, University of Washington, Seattle, WA 98195-5013, USA
| | - Valerie Daggett
- Molecular Engineering Program, University of Washington, Seattle, WA 98195-5013, USA,Department of Bioengineering, University of Washington, Seattle, WA 98195-5013, USA
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5
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Amyloid Aggregation of Streptococcus mutans Cnm Influences Its Collagen-Binding Activity. Appl Environ Microbiol 2021; 87:e0114921. [PMID: 34406827 PMCID: PMC8516039 DOI: 10.1128/aem.01149-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The cnm gene, coding for the glycosylated collagen- and laminin-binding surface adhesin Cnm, is found in the genomes of approximately 20% of Streptococcus mutans clinical isolates and is associated with systemic infections and increased caries risk. Other surface-associated collagen-binding proteins of S. mutans, such as P1 and WapA, have been demonstrated to form an amyloid quaternary structure with functional implications within biofilms. In silico analysis predicted that the β-sheet-rich N-terminal collagen-binding domain (CBD) of Cnm has a propensity for amyloid aggregation, whereas the threonine-rich C-terminal domain was predicted to be disorganized. In this study, thioflavin-T fluorescence and electron microscopy were used to show that Cnm forms amyloids in either its native glycosylated or recombinant nonglycosylated form and that the CBD of Cnm is the main amyloidogenic unit of Cnm. We then performed a series of in vitro, ex vivo, and in vivo assays to characterize the amylogenic properties of Cnm. In addition, Congo red birefringence indicated that Cnm is a major amyloidogenic protein of S. mutans biofilms. Competitive binding assays using collagen-coated microtiter plates and dental roots, a substrate rich in collagen, revealed that Cnm monomers inhibit S. mutans binding to collagenous substrates, whereas Cnm amyloid aggregates lose this property. Thus, while Cnm contributes to recognition and initial binding of S. mutans to collagen-rich surfaces, amyloid formation by Cnm might act as a negative regulatory mechanism to modulate collagen-binding activity within S. mutans biofilms and warrants further investigation. IMPORTANCE Streptococcus mutans is a keystone pathogen that promotes caries by acidifying the dental biofilm milieu. The collagen- and laminin-binding glycoprotein Cnm is a virulence factor of S. mutans. Expression of Cnm by S. mutans is hypothesized to contribute to niche expansion, allowing colonization of multiple sites in the body, including collagen-rich surfaces such as dentin and heart valves. Here, we suggest that Cnm function might be modulated by its aggregation status. As a monomer, its primary function is to promote attachment to collagenous substrates via its collagen-binding domain (CBD). However, in later stages of biofilm maturation, the same CBD of Cnm could self-assemble into amyloid fibrils, losing the ability to bind to collagen and likely becoming a component of the biofilm matrix. Our findings shed light on the role of functional amyloids in S. mutans pathobiology and ecology.
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Zhang Y, Liu Y, Tang Y, Zhang D, He H, Wu J, Zheng J. Antimicrobial α-defensins as multi-target inhibitors against amyloid formation and microbial infection. Chem Sci 2021; 12:9124-9139. [PMID: 34276942 PMCID: PMC8261786 DOI: 10.1039/d1sc01133b] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/27/2021] [Indexed: 12/22/2022] Open
Abstract
Amyloid aggregation and microbial infection are considered as pathological risk factors for developing amyloid diseases, including Alzheimer's disease (AD), type II diabetes (T2D), Parkinson's disease (PD), and medullary thyroid carcinoma (MTC). Due to the multifactorial nature of amyloid diseases, single-target drugs and treatments have mostly failed to inhibit amyloid aggregation and microbial infection simultaneously, thus leading to marginal benefits for amyloid inhibition and medical treatments. Herein, we proposed and demonstrated a new "anti-amyloid and antimicrobial hypothesis" to discover two host-defense antimicrobial peptides of α-defensins containing β-rich structures (human neutrophil peptide of HNP-1 and rabbit neutrophil peptide of NP-3A), which have demonstrated multi-target, sequence-independent functions to (i) prevent the aggregation and misfolding of different amyloid proteins of amyloid-β (Aβ, associated with AD), human islet amyloid polypeptide (hIAPP, associated with T2D), and human calcitonin (hCT, associated with MTC) at sub-stoichiometric concentrations, (ii) reduce amyloid-induced cell toxicity, and (iii) retain their original antimicrobial activity upon the formation of complexes with amyloid peptides. Further structural analysis showed that the sequence-independent amyloid inhibition function of α-defensins mainly stems from their cross-interactions with amyloid proteins via β-structure interactions. The discovery of antimicrobial peptides containing β-structures to inhibit both microbial infection and amyloid aggregation greatly expands the new therapeutic potential of antimicrobial peptides as multi-target amyloid inhibitors for better understanding pathological causes and treatments of amyloid diseases.
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Affiliation(s)
- Yanxian Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron Ohio USA
| | - Yonglan Liu
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron Ohio USA
| | - Yijing Tang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron Ohio USA
| | - Dong Zhang
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron Ohio USA
| | - Huacheng He
- College of Chemistry and Materials Engineering, Wenzhou University Zhejiang China
| | - Jiang Wu
- School of Pharmaceutical Sciences, Wenzhou Medical University Zhejiang China
| | - Jie Zheng
- Department of Chemical, Biomolecular, and Corrosion Engineering, The University of Akron Ohio USA
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7
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Masrati G, Landau M, Ben-Tal N, Lupas A, Kosloff M, Kosinski J. Integrative Structural Biology in the Era of Accurate Structure Prediction. J Mol Biol 2021; 433:167127. [PMID: 34224746 DOI: 10.1016/j.jmb.2021.167127] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 11/16/2022]
Abstract
Characterizing the three-dimensional structure of macromolecules is central to understanding their function. Traditionally, structures of proteins and their complexes have been determined using experimental techniques such as X-ray crystallography, NMR, or cryo-electron microscopy-applied individually or in an integrative manner. Meanwhile, however, computational methods for protein structure prediction have been improving their accuracy, gradually, then suddenly, with the breakthrough advance by AlphaFold2, whose models of monomeric proteins are often as accurate as experimental structures. This breakthrough foreshadows a new era of computational methods that can build accurate models for most monomeric proteins. Here, we envision how such accurate modeling methods can combine with experimental structural biology techniques, enhancing integrative structural biology. We highlight the challenges that arise when considering multiple structural conformations, protein complexes, and polymorphic assemblies. These challenges will motivate further developments, both in modeling programs and in methods to solve experimental structures, towards better and quicker investigation of structure-function relationships.
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Affiliation(s)
- Gal Masrati
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel; European Molecular Biology Laboratory (EMBL), Hamburg 22607, Germany
| | - Nir Ben-Tal
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Andrei Lupas
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
| | - Mickey Kosloff
- Department of Human Biology, Faculty of Natural Sciences, University of Haifa, 199 Aba Khoushy Ave., Mt. Carmel, 3498838 Haifa, Israel.
| | - Jan Kosinski
- European Molecular Biology Laboratory (EMBL), Hamburg 22607, Germany; Centre for Structural Systems Biology (CSSB), Hamburg 22607, Germany; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
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8
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Overstreet AMC, Grayson BE, Boger A, Bakke D, Carmody EM, Bales CE, Paski SC, Murphy SF, Dethlefs CR, Shannon KJ, Adlaka KR, Wolford CE, Campiti VJ, Raghunandan CV, Seeley RJ, Boone DL. Gastrokine-1, an anti-amyloidogenic protein secreted by the stomach, regulates diet-induced obesity. Sci Rep 2021; 11:9477. [PMID: 33947892 PMCID: PMC8096951 DOI: 10.1038/s41598-021-88928-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 04/19/2021] [Indexed: 12/27/2022] Open
Abstract
Obesity and its sequelae have a major impact on human health. The stomach contributes to obesity in ways that extend beyond its role in digestion, including through effects on the microbiome. Gastrokine-1 (GKN1) is an anti-amyloidogenic protein abundantly and specifically secreted into the stomach lumen. We examined whether GKN1 plays a role in the development of obesity and regulation of the gut microbiome. Gkn1-/- mice were resistant to diet-induced obesity and hepatic steatosis (high fat diet (HFD) fat mass (g) = 10.4 ± 3.0 (WT) versus 2.9 ± 2.3 (Gkn1-/-) p < 0.005; HFD liver mass (g) = 1.3 ± 0.11 (WT) versus 1.1 ± 0.07 (Gkn1-/-) p < 0.05). Gkn1-/- mice also exhibited increased expression of the lipid-regulating hormone ANGPTL4 in the small bowel. The microbiome of Gkn1-/- mice exhibited reduced populations of microbes implicated in obesity, namely Firmicutes of the class Erysipelotrichia. Altered metabolism consistent with use of fat as an energy source was evident in Gkn1-/- mice during the sleep period. GKN1 may contribute to the effects of the stomach on the microbiome and obesity. Inhibition of GKN1 may be a means to prevent obesity.
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Affiliation(s)
- Anne-Marie C Overstreet
- Department of Microbiology and Immunology, Indiana University School of Medicine-South Bend, RCH122, 1234 N. Notre Dame Ave., South Bend, IN, 46617, USA
| | - Bernadette E Grayson
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, USA
| | - Antonia Boger
- Department of Microbiology and Immunology, Indiana University School of Medicine-South Bend, RCH122, 1234 N. Notre Dame Ave., South Bend, IN, 46617, USA
| | - Danika Bakke
- Department of Microbiology and Immunology, Indiana University School of Medicine-South Bend, RCH122, 1234 N. Notre Dame Ave., South Bend, IN, 46617, USA
| | - Erin M Carmody
- Department of Biology, University of Notre Dame, South Bend, IN, USA
| | - Cayla E Bales
- Department of Biology, University of Notre Dame, South Bend, IN, USA
| | | | - Stephen F Murphy
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | | | - Kara J Shannon
- Department of Biology, University of Notre Dame, South Bend, IN, USA
| | - Katie R Adlaka
- Department of Biology, University of Notre Dame, South Bend, IN, USA
| | - Claire E Wolford
- Department of Biology, University of Notre Dame, South Bend, IN, USA
| | - Vincent J Campiti
- Department of Microbiology and Immunology, Indiana University School of Medicine-South Bend, RCH122, 1234 N. Notre Dame Ave., South Bend, IN, 46617, USA
| | - Christina V Raghunandan
- Department of Microbiology and Immunology, Indiana University School of Medicine-South Bend, RCH122, 1234 N. Notre Dame Ave., South Bend, IN, 46617, USA
| | - Randy J Seeley
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
- Department of Surgery, University of Michigan Health System, Ann Arbor, MI, USA
| | - David L Boone
- Department of Microbiology and Immunology, Indiana University School of Medicine-South Bend, RCH122, 1234 N. Notre Dame Ave., South Bend, IN, 46617, USA.
- Department of Biology, University of Notre Dame, South Bend, IN, USA.
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9
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Emerging Roles of Functional Bacterial Amyloids in Gene Regulation, Toxicity, and Immunomodulation. Microbiol Mol Biol Rev 2020; 85:85/1/e00062-20. [PMID: 33239434 DOI: 10.1128/mmbr.00062-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria often reside in multicellular communities, called biofilms, held together by an extracellular matrix. In many bacteria, the major proteinaceous component of the biofilm are amyloid fibers. Amyloids are highly stable and structured protein aggregates which were known mostly to be associated with neurodegenerative diseases, such as Alzheimer's, Parkinson's, and Huntington's diseases. In recent years, microbial amyloids were identified also in other species and shown to play major roles in microbial physiology and virulence. For example, amyloid fibers assemble on the bacterial cell surface as a part of the extracellular matrix and are extremely important to the scaffolding and structural integrity of biofilms, which contribute to microbial resilience and resistance. Furthermore, microbial amyloids play fundamental nonscaffold roles that contribute to the development of biofilms underlying numerous persistent infections. Here, we review several nonscaffold roles of bacterial amyloid proteins, including bridging cells during collective migration, acting as regulators of cell fate, as toxins against other bacteria or against host immune cells, and as modulators of the hosts' immune system. These overall points on the complexity of the amyloid fold in encoding numerous activities, which offer approaches for the development of a novel repertoire of antivirulence therapeutics.
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10
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Juhl DW, Glattard E, Lointier M, Bampilis P, Bechinger B. The Reversible Non-covalent Aggregation Into Fibers of PGLa and Magainin 2 Preserves Their Antimicrobial Activity and Synergism. Front Cell Infect Microbiol 2020; 10:526459. [PMID: 33102247 PMCID: PMC7554302 DOI: 10.3389/fcimb.2020.526459] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 08/18/2020] [Indexed: 01/29/2023] Open
Abstract
Magainin 2 and PGLa are antimicrobial peptides found together in frog skin secretions. When added as a mixture they show an order of magnitude increase in antibacterial activity and in model membrane permeation assays. Here we demonstrate that both peptides can form fibers with beta-sheet/turn signature in ATR-FTIR- and CD-spectroscopic analyses, but with different morphologies in EM images. Whereas, fiber formation results in acute reduction of the antimicrobial activity of the individual peptides, the synergistic enhancement of activity remains for the equimolar mixture of PGLa and magainin 2 also after fibril formation. The biological significance and potential applications of such supramolecular aggregates are discussed.
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Affiliation(s)
- Dennis Wilkens Juhl
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
| | - Elise Glattard
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
| | - Morane Lointier
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
| | - Panos Bampilis
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
| | - Burkhard Bechinger
- University of Strasbourg/CNRS, UMR7177, Institut de Chimie de Strasbourg, Strasbourg, France
- Institut Universitaire de France (IUF), Paris, France
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11
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Ke PC, Zhou R, Serpell LC, Riek R, Knowles TPJ, Lashuel HA, Gazit E, Hamley IW, Davis TP, Fändrich M, Otzen DE, Chapman MR, Dobson CM, Eisenberg DS, Mezzenga R. Half a century of amyloids: past, present and future. Chem Soc Rev 2020; 49:5473-5509. [PMID: 32632432 PMCID: PMC7445747 DOI: 10.1039/c9cs00199a] [Citation(s) in RCA: 304] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Amyloid diseases are global epidemics with profound health, social and economic implications and yet remain without a cure. This dire situation calls for research into the origin and pathological manifestations of amyloidosis to stimulate continued development of new therapeutics. In basic science and engineering, the cross-β architecture has been a constant thread underlying the structural characteristics of pathological and functional amyloids, and realizing that amyloid structures can be both pathological and functional in nature has fuelled innovations in artificial amyloids, whose use today ranges from water purification to 3D printing. At the conclusion of a half century since Eanes and Glenner's seminal study of amyloids in humans, this review commemorates the occasion by documenting the major milestones in amyloid research to date, from the perspectives of structural biology, biophysics, medicine, microbiology, engineering and nanotechnology. We also discuss new challenges and opportunities to drive this interdisciplinary field moving forward.
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Affiliation(s)
- Pu Chun Ke
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Zhongshan Hospital, Fudan University, 111 Yixueyuan Rd, Xuhui District, Shanghai, China
| | - Ruhong Zhou
- Institute of Quantitative Biology, Zhejiang University, Hangzhou 310058, China; Department of Chemistry, Columbia University, New York, New York, 10027, USA
| | - Louise C. Serpell
- School of Life Sciences, University of Sussex, Falmer, East Sussex BN1 9QG, UK
| | - Roland Riek
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Wolfgang-Pauli-Str. 10, 8093 Zurich, Switzerland
| | - Tuomas P. J. Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
- Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, CB3 0HE, Cambridge, UK
| | - Hilal A. Lashuel
- Laboratory of Molecular Neurobiology and Neuroproteomics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Ehud Gazit
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences; Department of Materials Science and Engineering, Iby and Aladar Fleischman Faculty of Engineering, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Ian W. Hamley
- School of Chemistry, Food Biosciences and Pharmacy, University of Reading, Whiteknights, Reading RG6 6AD, UK
| | - Thomas P. Davis
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC 3052, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane Qld 4072, Australia
| | - Marcus Fändrich
- Institute of Protein Biochemistry, Ulm University, 89081, Ulm, Germany
| | - Daniel Erik Otzen
- Department of Molecular Biology, Center for Insoluble Protein Structures (inSPIN), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Matthew R. Chapman
- Department of Molecular, Cellular and Developmental Biology, Centre for Microbial Research, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Christopher M. Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - David S. Eisenberg
- Departments of Chemistry and Biochemistry and Biological Chemistry, UCLA-DOE Institute and Howard Hughes Medical Institute, UCLA, Los Angeles, CA, USA
| | - Raffaele Mezzenga
- Department of Health Science & Technology, ETH Zurich, Schmelzbergstrasse 9, LFO, E23, 8092 Zurich, Switzerland
- Department of Materials, ETH Zurich, Wolfgang Pauli Strasse 10, 8093 Zurich, Switzerland
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12
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Racine PJ, Janvier X, Clabaut M, Catovic C, Souak D, Boukerb AM, Groboillot A, Konto-Ghiorghi Y, Duclairoir-Poc C, Lesouhaitier O, Orange N, Chevalier S, Feuilloley MGJ. Dialog between skin and its microbiota: Emergence of "Cutaneous Bacterial Endocrinology". Exp Dermatol 2020; 29:790-800. [PMID: 32682345 DOI: 10.1111/exd.14158] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/30/2020] [Accepted: 07/13/2020] [Indexed: 12/13/2022]
Abstract
Microbial endocrinology is studying the response of microorganisms to hormones and neurohormones and the microbiota production of hormones-like molecules. Until now, it was mainly applied to the gut and revealed that the intestinal microbiota should be considered as a real organ in constant and bilateral interactions with the whole human body. The skin harbours the second most abundant microbiome and contains an abundance of nerve terminals and capillaries, which in addition to keratinocytes, fibroblasts, melanocytes, dendritic cells and endothelial cells, release a huge diversity of hormones and neurohormones. In the present review, we will examine recent experimental data showing that, in skin, molecules such as substance P, calcitonin gene-related peptide, natriuretic peptides and catecholamines can directly affect the physiology and virulence of common skin-associated bacteria. Conversely, bacteria are able to synthesize and release compounds including histamine, glutamate and γ-aminobutyric acid or peptides showing partial homology with neurohormones such as α-melanocyte-stimulating hormone (αMSH). The more surprising is that some viruses can also encode neurohormones mimicking proteins. Taken together, these elements demonstrate that there is also a cutaneous microbial endocrinology and this emerging concept will certainly have important consequences in dermatology.
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Affiliation(s)
- Pierre-Jean Racine
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Xavier Janvier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Maximilien Clabaut
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Chloe Catovic
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Djouhar Souak
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Amine M Boukerb
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Anne Groboillot
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Yoan Konto-Ghiorghi
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Cécile Duclairoir-Poc
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Olivier Lesouhaitier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Nicole Orange
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Sylvie Chevalier
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
| | - Marc G J Feuilloley
- Laboratory of Microbiology Signals and Microenvironment LMSM EA4312, University of Rouen Normandy, Normandie Université, Evreux, France
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13
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Kantsler V, Ontañón-McDonald E, Kuey C, Ghanshyam MJ, Roffin MC, Asally M. Pattern Engineering of Living Bacterial Colonies Using Meniscus-Driven Fluidic Channels. ACS Synth Biol 2020; 9:1277-1283. [PMID: 32491836 DOI: 10.1021/acssynbio.0c00146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Creating adaptive, sustainable, and dynamic biomaterials is a forthcoming mission of synthetic biology. Engineering spatially organized bacterial communities has a potential to develop such bio-metamaterials. However, generating living patterns with precision, robustness, and a low technical barrier remains as a challenge. Here we present an easily implementable technique for patterning live bacterial populations using a controlled meniscus-driven fluidics system, named as MeniFluidics. We demonstrate multiscale patterning of biofilm colonies and swarms with submillimeter resolution. Utilizing the faster bacterial spreading in liquid channels, MeniFluidics allows controlled bacterial colonies both in space and time to organize fluorescently labeled Bacillus subtilis strains into a converged pattern and to form dynamic vortex patterns in confined bacterial swarms. The robustness, accuracy, and low technical barrier of MeniFluidics offer a tool for advancing and inventing new living materials that can be combined with genetically engineered systems, and adding to fundamental research into ecological, evolutional, and physical interactions between microbes.
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Affiliation(s)
- Vasily Kantsler
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom
| | | | - Cansu Kuey
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Manjari J. Ghanshyam
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Maria Chiara Roffin
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Munehiro Asally
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
- Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry CV4 7AL, United Kingdom
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14
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Tayeb-Fligelman E, Salinas N, Tabachnikov O, Landau M. Staphylococcus aureus PSMα3 Cross-α Fibril Polymorphism and Determinants of Cytotoxicity. Structure 2020; 28:301-313.e6. [DOI: 10.1016/j.str.2019.12.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 10/15/2019] [Accepted: 12/16/2019] [Indexed: 10/25/2022]
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15
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Structural Insights into Curli CsgA Cross-β Fibril Architecture Inspire Repurposing of Anti-amyloid Compounds as Anti-biofilm Agents. PLoS Pathog 2019; 15:e1007978. [PMID: 31469892 PMCID: PMC6748439 DOI: 10.1371/journal.ppat.1007978] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 09/17/2019] [Accepted: 07/11/2019] [Indexed: 12/14/2022] Open
Abstract
Curli amyloid fibrils secreted by Enterobacteriaceae mediate host cell adhesion and contribute to biofilm formation, thereby promoting bacterial resistance to environmental stressors. Here, we present crystal structures of amyloid-forming segments from the major curli subunit, CsgA, revealing steric zipper fibrils of tightly mated β-sheets, demonstrating a structural link between curli and human pathological amyloids. D-enantiomeric peptides, originally developed to interfere with Alzheimer's disease-associated amyloid-β, inhibited CsgA fibrillation and reduced biofilm formation in Salmonella typhimurium. Moreover, as previously shown, CsgA fibrils cross-seeded fibrillation of amyloid-β, providing support for the proposed structural resemblance and potential for cross-species amyloid interactions. The presented findings provide structural insights into amyloidogenic regions important for curli formation, suggest a novel strategy for disrupting amyloid-structured biofilms, and hypothesize on the formation of self-propagating prion-like species originating from a microbial source that could influence neurodegenerative diseases.
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16
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Holtrup S, Heimerl T, Linne U, Altegoer F, Noll F, Waidner B. Biochemical characterization of the Helicobacter pylori bactofilin-homolog HP1542. PLoS One 2019; 14:e0218474. [PMID: 31233532 PMCID: PMC6590870 DOI: 10.1371/journal.pone.0218474] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/03/2019] [Indexed: 01/11/2023] Open
Abstract
The human pathogen Helicobacter pylori is known for its colonization of the upper digestive system, where it escapes the harsh acidic environment by hiding in the mucus layer. One factor promoting this colonization is the helical cell shape of H. pylori. Among shape determining proteins are cytoskeletal elements like the recently discovered bactofilins. Bactofilins constitute a widespread family of polymer-forming bacterial proteins whose biology is still poorly investigated. Here we describe the first biochemical analysis of the bactofilin HP1542 of H. pylori reference strain 26695. Purified HP1542 forms sheet-like 2D crystalline assemblies, which clearly depend on a natively structured C-terminus. Polymerization properties and protein stability were investigated. Additionally, we also could demarcate HP1542 from amyloid proteins that share similarities with the bactofilin DUF domain. By using zonal centrifugation of total H. pylori cell lysates and immunfluorescence analysis we revealed peripheral membrane association of HP1542 mostly pronounced near mid-cell. Interestingly our results indicate that H. pylori bactofilin does not contribute to cell wall stability. This study might act as a starting point for biophysical studies of the H. pylori bactofilin biology as well as for the investigation of bactofilin cell physiology in this organism. Importantly, this study is the first biochemical analysis of a bactofilin in a human pathogen.
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Affiliation(s)
- Sven Holtrup
- LOEWE Center for Synthetic Microbiology, Philipps-Universität, Marburg, Germany
- Faculty of Chemistry, Philipps-Universität, Marburg, Germany
| | - Thomas Heimerl
- LOEWE Center for Synthetic Microbiology, Philipps-Universität, Marburg, Germany
- Faculty of Biology, Philipps-Universität, Marburg, Germany
| | - Uwe Linne
- Faculty of Chemistry, Philipps-Universität, Marburg, Germany
| | - Florian Altegoer
- LOEWE Center for Synthetic Microbiology, Philipps-Universität, Marburg, Germany
- Faculty of Chemistry, Philipps-Universität, Marburg, Germany
| | - Frank Noll
- Faculty of Chemistry, Philipps-Universität, Marburg, Germany
| | - Barbara Waidner
- LOEWE Center for Synthetic Microbiology, Philipps-Universität, Marburg, Germany
- Faculty of Chemistry, Philipps-Universität, Marburg, Germany
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17
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Reichmann D, Voth W, Jakob U. Maintaining a Healthy Proteome during Oxidative Stress. Mol Cell 2019; 69:203-213. [PMID: 29351842 DOI: 10.1016/j.molcel.2017.12.021] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 12/11/2017] [Accepted: 12/21/2017] [Indexed: 12/11/2022]
Abstract
Some of the most challenging stress conditions that organisms encounter during their lifetime involve the transient accumulation of reactive oxygen and chlorine species. Extremely reactive to amino acid side chains, these oxidants cause widespread protein unfolding and aggregation. It is therefore not surprising that cells draw on a variety of different strategies to counteract the damage and maintain a healthy proteome. Orchestrated largely by direct changes in the thiol oxidation status of key proteins, the response strategies involve all layers of protein protection. Reprogramming of basic biological functions helps decrease nascent protein synthesis and restore redox homeostasis. Mobilization of oxidative stress-activated chaperones and production of stress-resistant non-proteinaceous chaperones prevent irreversible protein aggregation. Finally, redox-controlled increase in proteasome activity removes any irreversibly damaged proteins. Together, these systems pave the way to restore protein homeostasis and enable organisms to survive stress conditions that are inevitable when living an aerobic lifestyle.
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Affiliation(s)
- Dana Reichmann
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Safra Campus Givat Ram, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| | - Wilhelm Voth
- Department of Molecular, Cellular, and Developmental Biology and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Ursula Jakob
- Department of Molecular, Cellular, and Developmental Biology and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109-1048, USA.
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18
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Paranjapye N, Daggett V. De Novo Designed α-Sheet Peptides Inhibit Functional Amyloid Formation of Streptococcus mutans Biofilms. J Mol Biol 2018; 430:3764-3773. [PMID: 30006266 PMCID: PMC6168415 DOI: 10.1016/j.jmb.2018.07.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 06/29/2018] [Accepted: 07/02/2018] [Indexed: 12/11/2022]
Abstract
Streptococcus mutans is a bacterial species that predominates in the oral microbiome. S. mutans binds to the tooth surface, metabolizes sugars and produces acid, leading to cavity formation. S. mutans can also cause infectious endocarditis. Recent evidence suggests that S. mutans biofilms contain amyloid fibrils. Amyloids are insoluble fibrillar protein aggregates, and bacteria use functional amyloids to improve robustness of their biofilms. While the functional amyloids in bacteria such as Escherichia coli and Staphylococcus aureus have been heavily investigated, little is known about the mechanism of S. mutans amyloid formation. Previous results from our laboratory with the amyloidogenic proteins and peptides from the aforementioned bacteria and other mammalian amyloid systems suggest that amyloid formation progresses via an intermediate that adopts a unique secondary structure-α-sheet. De novo designed peptides with alternating l- and d-amino acid also adopt an α-sheet secondary structure and inhibit amyloid formation by binding to soluble oligomeric species during amyloidogenesis. Inhibition of fibrillization by α-sheet peptides suggests the presence of α-sheet during amyloid formation. To investigate the mechanism of functional amyloid formation in S. mutans, α-sheet peptides were compared to epigallocatechin gallate for their ability to inhibit fibril formation in S. mutans. Inhibition was demonstrated in a biofilm plate assay and on hydroxyapatite surfaces both in S. mutans alone and in bacteria from human saliva. The observed inhibition suggests that an α-sheet mediated mechanism may be operative during functional amyloid formation.
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Affiliation(s)
- Natasha Paranjapye
- Department of Bioengineering, University of Washington, Box 355013, Seattle, WA 98195-5013, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Box 355013, Seattle, WA 98195-5013, USA.
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19
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Wang Y, Jiang J, Gao Y, Sun Y, Dai J, Wu Y, Qu D, Ma G, Fang X. Staphylococcus epidermidis small basic protein (Sbp) forms amyloid fibrils, consistent with its function as a scaffolding protein in biofilms. J Biol Chem 2018; 293:14296-14311. [PMID: 30049797 PMCID: PMC6139570 DOI: 10.1074/jbc.ra118.002448] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/24/2018] [Indexed: 12/12/2022] Open
Abstract
Biofilms are communities of microbes embedded in a microbial extracellular matrix. Their formation is considered the main virulence mechanism enabling the opportunistic bacterial pathogen Staphylococcus epidermidis to cause devastating nosocomial, implant-associated infections. Biofilms often contain proteins, and an 18-kDa protein called small basic protein (Sbp) recently was discovered in the S. epidermidis biofilm matrix and may serve as a scaffolding protein in both polysaccharide intercellular adhesin (PIA)-dependent and accumulation-associated protein (Aap)-dependent biofilm formations. In Aap-mediated biofilm formation, Sbp colocalizes with Domain-B of Aap, implying that Sbp directly interacts with Aap's Domain-B. However, the structure of Sbp and its interaction with Aap, as well as the molecular mechanism underlying Sbp's roles in biofilm formation, are incompletely understood. In this work, we used small-angle X-ray scattering (SAXS), NMR, analytical size-exclusion chromatography, and isothermal titration calorimetry analyses to determine the Sbp structure and characterize its interaction with Aap's Domain-B. We found that Sbp is monomeric and partially folded in solution, and, unexpectedly, we observed no direct interactions between Sbp and Aap Domain-B. Instead, we noted that Sbp forms amyloid fibrils both in vitro and in vivo Atomic force, transmission electron, and confocal fluorescence microscopy methods confirmed the formation of Sbp amyloid fibrils and revealed their morphology. Taken together, the Sbp amyloid fibril structures identified here may account for Sbp's role as a scaffolding protein in the S. epidermidis biofilm matrix.
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Affiliation(s)
- Yan Wang
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jingbo Jiang
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yachao Gao
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yang Sun
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jianfeng Dai
- Institutes of Biology and Medical Sciences, Jiangsu Key Laboratory of Infection and Immunity, Soochow University, Suzhou 215123, China
| | - Yang Wu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education and Ministry of Public Health, Department of Medical Microbiology and Parasitology, Shanghai Medical College of Fudan University, 138 Yixueyuan Road, Shanghai 200032, China, and
| | - Di Qu
- Key Laboratory of Medical Molecular Virology of the Ministry of Education and Ministry of Public Health, Department of Medical Microbiology and Parasitology, Shanghai Medical College of Fudan University, 138 Yixueyuan Road, Shanghai 200032, China, and
| | - Gang Ma
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
| | - Xianyang Fang
- From the Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China,
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20
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Extreme amyloid polymorphism in Staphylococcus aureus virulent PSMα peptides. Nat Commun 2018; 9:3512. [PMID: 30158633 PMCID: PMC6115460 DOI: 10.1038/s41467-018-05490-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/10/2018] [Indexed: 01/07/2023] Open
Abstract
Members of the Staphylococcus aureus phenol-soluble modulin (PSM) peptide family are secreted as functional amyloids that serve diverse roles in pathogenicity and may be present as full-length peptides or as naturally occurring truncations. We recently showed that the activity of PSMα3, the most toxic member, stems from the formation of cross-α fibrils, which are at variance with the cross-β fibrils linked with eukaryotic amyloid pathologies. Here, we show that PSMα1 and PSMα4, involved in biofilm structuring, form canonical cross-β amyloid fibrils wherein β-sheets tightly mate through steric zipper interfaces, conferring high stability. Contrastingly, a truncated PSMα3 has antibacterial activity, forms reversible fibrils, and reveals two polymorphic and atypical β-rich fibril architectures. These architectures are radically different from both the cross-α fibrils formed by full-length PSMα3, and from the canonical cross-β fibrils. Our results point to structural plasticity being at the basis of the functional diversity exhibited by S. aureus PSMαs.
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21
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Bleem A, Christiansen G, Madsen DJ, Maric H, Strømgaard K, Bryers JD, Daggett V, Meyer RL, Otzen DE. Protein Engineering Reveals Mechanisms of Functional Amyloid Formation in Pseudomonas aeruginosa Biofilms. J Mol Biol 2018; 430:3751-3763. [PMID: 29964047 DOI: 10.1016/j.jmb.2018.06.043] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/22/2018] [Accepted: 06/25/2018] [Indexed: 11/25/2022]
Abstract
Amyloids are typically associated with neurodegenerative diseases, but recent research demonstrates that several bacteria utilize functional amyloid fibrils to fortify the biofilm extracellular matrix and thereby resist antibiotic treatments. In Pseudomonas aeruginosa, these fibrils are composed predominantly of FapC, a protein with high-sequence conservation among the genera. Previous studies established FapC as the major amyloid subunit, but its mechanism of fibril formation in P. aeruginosa remained largely unexplored. Here, we examine the FapC sequence in greater detail through a combination of bioinformatics and protein engineering, and we identify specific motifs that are implicated in amyloid formation. Sequence regions of high evolutionary conservation tend to coincide with regions of high amyloid propensity, and mutation of amyloidogenic motifs to a designed, non-amyloidogenic motif suppresses fibril formation in a pH-dependent manner. We establish the particular significance of the third repeat motif in promoting fibril formation and also demonstrate emergence of soluble oligomer species early in the aggregation pathway. The insights reported here expand our understanding of the mechanism of amyloid polymerization in P. aeruginosa, laying the foundation for development of new amyloid inhibitors to combat recalcitrant biofilm infections.
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Affiliation(s)
- Alissa Bleem
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Gunna Christiansen
- Department of Biomedicine-Medical Microbiology and Immunology, Aarhus University, 8000 Aarhus C, Denmark
| | - Daniel J Madsen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Hans Maric
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, University of Copenhagen, 2100 Copenhagen Ø, Denmark
| | - James D Bryers
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Daniel E Otzen
- Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark.
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22
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Malishev R, Tayeb-Fligelman E, David S, Meijler MM, Landau M, Jelinek R. Reciprocal Interactions between Membrane Bilayers and S. aureus PSMα3 Cross-α Amyloid Fibrils Account for Species-Specific Cytotoxicity. J Mol Biol 2018; 430:1431-1441. [DOI: 10.1016/j.jmb.2018.03.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 03/19/2018] [Accepted: 03/22/2018] [Indexed: 01/08/2023]
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23
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Peterson CP, Sauer C, Chatfield CH. The Extracellular Polymeric Substances of Legionella pneumophila Biofilms Contain Amyloid Structures. Curr Microbiol 2018; 75:736-744. [PMID: 29468303 DOI: 10.1007/s00284-018-1440-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 01/16/2018] [Indexed: 12/25/2022]
Abstract
Human infection by bacteria of the genus Legionella most often result in the pneumonia known as Legionnaires Disease. Legionella is found as a resident of adherent biofilms in man-made water systems. Disinfection efforts to prevent Legionella infections require a better understanding of the structures that promote Legionella surface attachment and biofilm colonization. Various enzymatic treatments, including multiple carbohydrate-targeting mixtures, failed to disrupt Legionella biofilms, despite the presence of carbohydrates in the biofilms as shown by biochemical methods and concanavalin-A lectin staining. Moreover, Legionella biofilms contained amyloids as detected by three microscopic staining methods (congo red, thioflavin T, and the amyloid-specific antibody WO2). Amyloid structures were seen in biofilms of both L. pneumophila and L. longbeachae, the two Legionella species most associated with human infection. Inhibition of amyloid assembly by congo red and thioflavin T limited both self-aggregation and surface attachment of L. pneumophila, indicating that functional amyloid structures have a key role in initial biofilm formation by these pathogenic bacteria.
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Affiliation(s)
- Casey P Peterson
- Department of Biological Sciences, SUNY Cortland, Cortland, NY, USA
| | - Cassidy Sauer
- Department of Biological Sciences, SUNY Cortland, Cortland, NY, USA
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24
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Tayeb-Fligelman E, Tabachnikov O, Moshe A, Goldshmidt-Tran O, Sawaya MR, Coquelle N, Colletier JP, Landau M. The cytotoxic Staphylococcus aureus PSMα3 reveals a cross-α amyloid-like fibril. Science 2017; 355:831-833. [PMID: 28232575 DOI: 10.1126/science.aaf4901] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 12/23/2016] [Accepted: 02/02/2017] [Indexed: 12/31/2022]
Abstract
Amyloids are ordered protein aggregates, found in all kingdoms of life, and are involved in aggregation diseases as well as in physiological activities. In microbes, functional amyloids are often key virulence determinants, yet the structural basis for their activity remains elusive. We determined the fibril structure and function of the highly toxic, 22-residue phenol-soluble modulin α3 (PSMα3) peptide secreted by Staphylococcus aureus PSMα3 formed elongated fibrils that shared the morphological and tinctorial characteristics of canonical cross-β eukaryotic amyloids. However, the crystal structure of full-length PSMα3, solved de novo at 1.45 angstrom resolution, revealed a distinctive "cross-α" amyloid-like architecture, in which amphipathic α helices stacked perpendicular to the fibril axis into tight self-associating sheets. The cross-α fibrillation of PSMα3 facilitated cytotoxicity, suggesting that this assembly mode underlies function in S. aureus.
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Affiliation(s)
- Einav Tayeb-Fligelman
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Orly Tabachnikov
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Asher Moshe
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Orit Goldshmidt-Tran
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Michael R Sawaya
- Department of Biological Chemistry, Department of Chemistry and Biochemistry, and Howard Hughes Medical Institute, University of California at Los Angeles, Los Angeles, CA 90095, USA
| | - Nicolas Coquelle
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes-CEA-CNRS UMR 5075, Grenoble 38044, France
| | - Jacques-Philippe Colletier
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes-CEA-CNRS UMR 5075, Grenoble 38044, France
| | - Meytal Landau
- Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.
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25
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Rouse SL, Hawthorne WJ, Berry JL, Chorev DS, Ionescu SA, Lambert S, Stylianou F, Ewert W, Mackie U, Morgan RML, Otzen D, Herbst FA, Nielsen PH, Dueholm M, Bayley H, Robinson CV, Hare S, Matthews S. A new class of hybrid secretion system is employed in Pseudomonas amyloid biogenesis. Nat Commun 2017; 8:263. [PMID: 28811582 PMCID: PMC5557850 DOI: 10.1038/s41467-017-00361-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 06/23/2017] [Indexed: 11/25/2022] Open
Abstract
Gram-negative bacteria possess specialised biogenesis machineries that facilitate the export of amyloid subunits for construction of a biofilm matrix. The secretion of bacterial functional amyloid requires a bespoke outer-membrane protein channel through which unfolded amyloid substrates are translocated. Here, we combine X-ray crystallography, native mass spectrometry, single-channel electrical recording, molecular simulations and circular dichroism measurements to provide high-resolution structural insight into the functional amyloid transporter from Pseudomonas, FapF. FapF forms a trimer of gated β-barrel channels in which opening is regulated by a helical plug connected to an extended coil-coiled platform spanning the bacterial periplasm. Although FapF represents a unique type of secretion system, it shares mechanistic features with a diverse range of peptide translocation systems. Our findings highlight alternative strategies for handling and export of amyloid protein sequences. Gram-negative bacteria assemble biofilms from amyloid fibres, which translocate across the outer membrane as unfolded amyloid precursors through a secretion system. Here, the authors characterise the structural details of the amyloid transporter FapF in Pseudomonas.
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Affiliation(s)
- Sarah L Rouse
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - William J Hawthorne
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Jamie-Lee Berry
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Dror S Chorev
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Sandra A Ionescu
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Sebastian Lambert
- Duke-NUS Medical School, 8 College Road, Singapore, 169857, Singapore
| | - Fisentzos Stylianou
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Wiebke Ewert
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Uma Mackie
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK.,Walthamstow School for Girls, London, E17 9RZ, UK
| | - R Marc L Morgan
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Centre for Insoluble Protein Structures (inSPIN), Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Florian-Alexander Herbst
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Per H Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Morten Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Hagan Bayley
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Carol V Robinson
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Stephen Hare
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK
| | - Stephen Matthews
- Department of Life Sciences, Imperial College London, South Kensington Campus, London, SW72AZ, UK.
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26
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Singh AK, Prakash P, Singh R, Nandy N, Firdaus Z, Bansal M, Singh RK, Srivastava A, Roy JK, Mishra B, Singh RK. Curcumin Quantum Dots Mediated Degradation of Bacterial Biofilms. Front Microbiol 2017; 8:1517. [PMID: 28848526 PMCID: PMC5552728 DOI: 10.3389/fmicb.2017.01517] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 07/28/2017] [Indexed: 12/23/2022] Open
Abstract
Bacterial biofilm has been reported to be associated with more than 80% of bacterial infections. Curcumin, a hydrophobic polyphenol compound, has anti-quorum sensing activity apart from having antimicrobial action. However, its use is limited by its poor aqueous solubility and rapid degradation. In this study, we attempted to prepare quantum dots of the drug curcumin in order to achieve enhanced solubility and stability and investigated for its antimicrobial and antibiofilm activity. We utilized a newer two-step bottom up wet milling approach to prepare Curcumin Quantum Dots (CurQDs) using acetone as a primary solvent. Minimum inhibitory concentration against select Gram-positive and Gram-negative bacteria was performed. The antibiofilm assay was performed at first using 96-well tissue culture plate and subsequently validated by Confocal Laser Scanning Microscopy. Further, biofilm matrix protein was isolated using formaldehyde sludge and TCA/Acetone precipitation method. Protein extracted was incubated with varying concentration of CurQDs for 4 h and was subjected to SDS–PAGE. Molecular docking study was performed to observe interaction between curcumin and phenol soluble modulins as well as curli proteins. The biophysical evidences obtained from TEM, SEM, UV-VIS, fluorescence, Raman spectroscopy, and zeta potential analysis confirmed the formation of curcumin quantum dots with increased stability and solubility. The MICs of curcumin quantum dots, as observed against both select gram positive and negative bacterial isolates, was observed to be significantly lower than native curcumin particles. On TCP assay, Curcumin observed to be having antibiofilm as well as biofilm degrading activity. Results of SDS–PAGE and molecular docking have shown interaction between biofilm matrix proteins and curcumin. The results indicate that aqueous solubility and stability of Curcumin can be achieved by preparing its quantum dots. The study also demonstrates that by sizing down the particle size has not only enhanced its antimicrobial properties but it has also shown its antibiofilm activities. Further, study is needed to elucidate the exact nature of interaction between curcumin and biofilm matrix proteins.
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Affiliation(s)
- Ashish K Singh
- Bacterial Biofilm and Drug Resistance Research Group, Department of Microbiology, Institute of Medical Sciences, Banaras Hindu UniversityVaranasi, India.,Molecular Immunology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu UniversityVaranasi, India
| | - Pradyot Prakash
- Bacterial Biofilm and Drug Resistance Research Group, Department of Microbiology, Institute of Medical Sciences, Banaras Hindu UniversityVaranasi, India
| | - Ranjana Singh
- Biophysics Laboratory, Department of Physics, Institute of Science, Banaras Hindu UniversityVaranasi, India
| | - Nabarun Nandy
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu UniversityVaranasi, India
| | - Zeba Firdaus
- Department of Medicinal Chemistry, Institute of Medical Sciences, Banaras Hindu UniversityVaranasi, India
| | - Monika Bansal
- Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu UniversityVaranasi, India
| | - Ranjan K Singh
- Biophysics Laboratory, Department of Physics, Institute of Science, Banaras Hindu UniversityVaranasi, India
| | - Anchal Srivastava
- Biophysics Laboratory, Department of Physics, Institute of Science, Banaras Hindu UniversityVaranasi, India.,Nano Research Laboratory, Department of Physics, Banaras Hindu UniversityVaranasi, India
| | - Jagat K Roy
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu UniversityVaranasi, India
| | - Brahmeshwar Mishra
- Department of Pharmaceutics, Indian Institute of Technology, Banaras Hindu UniversityVaranasi, India
| | - Rakesh K Singh
- Molecular Immunology Laboratory, Department of Biochemistry, Institute of Science, Banaras Hindu UniversityVaranasi, India
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27
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Innovative Solutions to Sticky Situations: Antiadhesive Strategies for Treating Bacterial Infections. Microbiol Spectr 2017; 4. [PMID: 27227305 DOI: 10.1128/microbiolspec.vmbf-0023-2015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial adherence to host tissue is an essential process in pathogenesis, necessary for invasion and colonization and often required for the efficient delivery of toxins and other bacterial effectors. As existing treatment options for common bacterial infections dwindle, we find ourselves rapidly approaching a tipping point in our confrontation with antibiotic-resistant strains and in desperate need of new treatment options. Bacterial strains defective in adherence are typically avirulent and unable to cause infection in animal models. The importance of this initial binding event in the pathogenic cascade highlights its potential as a novel therapeutic target. This article seeks to highlight a variety of strategies being employed to treat and prevent infection by targeting the mechanisms of bacterial adhesion. Advancements in this area include the development of novel antivirulence therapies using small molecules, vaccines, and peptides to target a variety of bacterial infections. These therapies target bacterial adhesion through a number of mechanisms, including inhibition of pathogen receptor biogenesis, competition-based strategies with receptor and adhesin analogs, and the inhibition of binding through neutralizing antibodies. While this article is not an exhaustive description of every advancement in the field, we hope it will highlight several promising examples of the therapeutic potential of antiadhesive strategies.
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28
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Bleem A, Francisco R, Bryers JD, Daggett V. Designed α-sheet peptides suppress amyloid formation in Staphylococcus aureus biofilms. NPJ Biofilms Microbiomes 2017; 3:16. [PMID: 28685098 PMCID: PMC5495782 DOI: 10.1038/s41522-017-0025-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 06/06/2017] [Accepted: 06/13/2017] [Indexed: 12/13/2022] Open
Abstract
Nosocomial infections affect hundreds of millions of patients worldwide each year, and ~60% of these infections are associated with biofilm formation on an implanted medical device. Biofilms are dense communities of microorganisms in which cells associate with surfaces and each other using a self-produced extracellular matrix composed of proteins, polysaccharides, and genetic material. Proteins in the extracellular matrix take on a variety of forms, but here we focus on functional amyloid structures. Amyloids have long been associated with protein misfolding and neurodegenerative diseases, but recent research has demonstrated that numerous bacterial species utilize the amyloid fold to fortify the biofilm matrix and resist disassembly. Consequently, these functional amyloids, in particular the soluble oligomeric intermediates formed during amyloidogenesis, represent targets to destabilize the extracellular matrix and interrupt biofilm formation. Our previous studies suggested that these amyloidogenic intermediates adopt a non-standard structure, termed "α-sheet", as they aggregate into soluble oligomeric species. This led to the design of complementary α-sheet peptides as anti-α-sheet inhibitors; these designs inhibit amyloidogenesis in three unrelated mammalian disease-associated systems through preferential binding of soluble oligomers. Here we show that these anti-α-sheet peptides inhibit amyloid formation in Staphylococcus aureus biofilms. Furthermore, they inhibit aggregation of pure, synthetic phenol soluble modulin α1, a major component of Staphylococcus aureus functional amyloids. As it aggregates phenol soluble modulin α1 adopts α-helix then α-sheet and finally forms β-sheet fibrils. The binding of the designed peptide inhibitors coincides with the formation of α-sheet.
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Affiliation(s)
- Alissa Bleem
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
| | - Robyn Francisco
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
| | - James D. Bryers
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Seattle, WA 98195-5013 USA
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29
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García-Bayona L, Guo MS, Laub MT. Contact-dependent killing by Caulobacter crescentus via cell surface-associated, glycine zipper proteins. eLife 2017; 6:e24869. [PMID: 28323618 PMCID: PMC5380434 DOI: 10.7554/elife.24869] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/20/2017] [Indexed: 12/18/2022] Open
Abstract
Most bacteria are in fierce competition with other species for limited nutrients. Some bacteria can kill nearby cells by secreting bacteriocins, a diverse group of proteinaceous antimicrobials. However, bacteriocins are typically freely diffusible, and so of little value to planktonic cells in aqueous environments. Here, we identify an atypical two-protein bacteriocin in the α-proteobacterium Caulobacter crescentus that is retained on the surface of producer cells where it mediates cell contact-dependent killing. The bacteriocin-like proteins CdzC and CdzD harbor glycine-zipper motifs, often found in amyloids, and CdzC forms large, insoluble aggregates on the surface of producer cells. These aggregates can drive contact-dependent killing of other organisms, or Caulobacter cells not producing the CdzI immunity protein. The Cdz system uses a type I secretion system and is unrelated to previously described contact-dependent inhibition systems. However, Cdz-like systems are found in many bacteria, suggesting that this form of contact-dependent inhibition is common.
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Affiliation(s)
- Leonor García-Bayona
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
- Graduate Program in Microbiology, Massachusetts Institute of Technology, Cambridge, United States
| | - Monica S Guo
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Michael T Laub
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States
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30
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Giraldo R, Fernández C, Moreno-del Álamo M, Molina-García L, Revilla-García A, Sánchez-Martínez MC, Giménez-Abián JF, Moreno-Díaz de la Espina S. RepA-WH1 prionoid: Clues from bacteria on factors governing phase transitions in amyloidogenesis. Prion 2017; 10:41-9. [PMID: 27040981 PMCID: PMC4981189 DOI: 10.1080/19336896.2015.1129479] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In bacterial plasmids, Rep proteins initiate DNA replication by undergoing a structural transformation coupled to dimer dissociation. Amyloidogenesis of the ‘winged-helix’ N-terminal domain of RepA (WH1) is triggered in vitro upon binding to plasmid-specific DNA sequences, and occurs at the bacterial nucleoid in vivo. Amyloid fibers are made of distorted RepA-WH1 monomers that assemble as single or double intertwined tubular protofilaments. RepA-WH1 causes in E. coli an amyloid proteinopathy, which is transmissible from mother to daughter cells, but not infectious, and enables conformational imprinting in vitro and in vivo; i.e. RepA-WH1 is a ‘prionoid’. Microfluidics allow the assessment of the intracellular dynamics of RepA-WH1: bacterial lineages maintain two types (strains-like) of RepA-WH1 amyloids, either multiple compact cytotoxic particles or a single aggregate with the appearance of a fluidized hydrogel that it is mildly detrimental to growth. The Hsp70 chaperone DnaK governs the phase transition between both types of RepA-WH1 aggregates in vivo, thus modulating the vertical propagation of the prionoid. Engineering chimeras between the Sup35p/[PSI+] prion and RepA-WH1 generates [REP-PSI+], a synthetic prion exhibiting strong and weak phenotypic variants in yeast. These recent findings on a synthetic, self-contained bacterial prionoid illuminate central issues of protein amyloidogenesis.
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Affiliation(s)
- Rafael Giraldo
- a Department of Cellular & Molecular Biology , Centro de Investigaciones Biológicas - CSIC , Madrid , Spain
| | - Cristina Fernández
- a Department of Cellular & Molecular Biology , Centro de Investigaciones Biológicas - CSIC , Madrid , Spain
| | - María Moreno-del Álamo
- a Department of Cellular & Molecular Biology , Centro de Investigaciones Biológicas - CSIC , Madrid , Spain
| | - Laura Molina-García
- a Department of Cellular & Molecular Biology , Centro de Investigaciones Biológicas - CSIC , Madrid , Spain
| | - Aída Revilla-García
- a Department of Cellular & Molecular Biology , Centro de Investigaciones Biológicas - CSIC , Madrid , Spain
| | | | - Juan F Giménez-Abián
- a Department of Cellular & Molecular Biology , Centro de Investigaciones Biológicas - CSIC , Madrid , Spain
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31
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Stenvang M, Dueholm MS, Vad BS, Seviour T, Zeng G, Geifman-Shochat S, Søndergaard MT, Christiansen G, Meyer RL, Kjelleberg S, Nielsen PH, Otzen DE. Epigallocatechin Gallate Remodels Overexpressed Functional Amyloids in Pseudomonas aeruginosa and Increases Biofilm Susceptibility to Antibiotic Treatment. J Biol Chem 2016; 291:26540-26553. [PMID: 27784787 DOI: 10.1074/jbc.m116.739953] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/07/2016] [Indexed: 01/09/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils. Here we show that EGCG inhibits the ability of Fap to form fibrils; instead, EGCG stabilizes protein oligomers. Existing fibrils are remodeled by EGCG into non-amyloid aggregates. This fibril remodeling increases the binding of pyocyanin, demonstrating a mechanism by which EGCG can affect the QS function of functional amyloid. EGCG reduced the amyloid-specific fluorescent thioflavin T signal in P. aeruginosa biofilms at concentrations known to exert an antimicrobial effect. Nanoindentation studies showed that EGCG reduced the stiffness of biofilm containing Fap fibrils but not in biofilm with little Fap. In a combination treatment with EGCG and tobramycin, EGCG had a moderate effect on the minimum bactericidal eradication concentration against wild-type P. aeruginosa biofilms, whereas EGCG had a more pronounced effect when Fap was overexpressed. Our results provide a direct molecular explanation for the ability of EGCG to disrupt P. aeruginosa QS and modify its biofilm and strengthens the case for EGCG as a candidate in multidrug treatment of persistent biofilm infections.
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Affiliation(s)
- Marcel Stenvang
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN).,the Sino-Danish Centre for Education and Research (SDC), 8000 Aarhus C, Denmark
| | - Morten S Dueholm
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | - Brian S Vad
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
| | - Thomas Seviour
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | | | - Susana Geifman-Shochat
- the School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore, and
| | - Mads T Søndergaard
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | | | - Rikke Louise Meyer
- From the Interdisciplinary Nanoscience Center (iNANO).,the Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Staffan Kjelleberg
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore.,the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Per Halkjær Nielsen
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark.,the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Center (iNANO), .,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
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32
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Dissecting the contribution of Staphylococcus aureus α-phenol-soluble modulins to biofilm amyloid structure. Sci Rep 2016; 6:34552. [PMID: 27708403 PMCID: PMC5052566 DOI: 10.1038/srep34552] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/15/2016] [Indexed: 11/23/2022] Open
Abstract
The opportunistic pathogen Staphylococcus aureus is recognized as one of the most frequent causes of biofilm-associated infections. The recently discovered phenol soluble modulins (PSMs) are small α-helical amphipathic peptides that act as the main molecular effectors of staphylococcal biofilm maturation, promoting the formation of an extracellular fibril structure with amyloid-like properties. Here, we combine computational, biophysical and in cell analysis to address the specific contribution of individual PSMs to biofilm structure. We demonstrate that despite their highly similar sequence and structure, contrary to what it was previously thought, not all PSMs participate in amyloid fibril formation. A balance of hydrophobic/hydrophilic forces and helical propensity seems to define the aggregation propensity of PSMs and control their assembly and function. This knowledge would allow to target specifically the amyloid properties of these peptides. In this way, we show that Epigallocatechin-3-gallate (EGCG), the principal polyphenol in green tea, prevents the assembly of amyloidogenic PSMs and disentangles their preformed amyloid fibrils.
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33
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Abstract
Recent insights into bacterial biofilm matrix structures have induced a paradigm shift toward the recognition of amyloid fibers as common building block structures that confer stability to the exopolysaccharide matrix. Here we describe the functional amyloid systems related to biofilm matrix formation in both Gram-negative and Gram-positive bacteria and recent knowledge regarding the interaction of amyloids with other biofilm matrix components such as extracellular DNA (eDNA) and the host immune system. In addition, we summarize the efforts to identify compounds that target amyloid fibers for therapeutic purposes and recent developments that take advantage of the amyloid structure to engineer amyloid fibers of bacterial biofilm matrices for biotechnological applications.
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34
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Bleem A, Daggett V. Structural and functional diversity among amyloid proteins: Agents of disease, building blocks of biology, and implications for molecular engineering. Biotechnol Bioeng 2016; 114:7-20. [PMID: 27474784 DOI: 10.1002/bit.26059] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 12/23/2022]
Abstract
Amyloids have long been associated with protein dysfunction and neurodegenerative diseases, but recent research has demonstrated that some organisms utilize the unique properties of the amyloid fold to create functional structures with important roles in biological processes. Additionally, new engineering approaches have taken advantage of amyloid structures for implementation in a wide variety of materials and devices. In this review, the role of amyloid in human disease is discussed and compared to the functional amyloids, which serve a largely structural purpose. We then consider the use of amyloid constructs in engineering applications, including their utility as building blocks for synthetic biology and molecular engineering. Biotechnol. Bioeng. 2017;114: 7-20. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Alissa Bleem
- Department of Bioengineering, University of Washington, Box 355013, Seattle, Washington, 98195-5013
| | - Valerie Daggett
- Department of Bioengineering, University of Washington, Box 355013, Seattle, Washington, 98195-5013
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35
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Louros NN, Bolas GMP, Tsiolaki PL, Hamodrakas SJ, Iconomidou VA. Intrinsic aggregation propensity of the CsgB nucleator protein is crucial for curli fiber formation. J Struct Biol 2016; 195:179-189. [PMID: 27245712 DOI: 10.1016/j.jsb.2016.05.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 05/26/2016] [Accepted: 05/28/2016] [Indexed: 11/28/2022]
Abstract
Several organisms exploit the extraordinary physical properties of amyloid fibrils forming natural protective amyloids, in an effort to support complex biological functions. Curli amyloid fibers are a major component of mature biofilms, which are produced by many Enterobacteriaceae species and are responsible, among other functions, for the initial adhesion of bacteria to surfaces or cells. The main axis of curli fibers is formed by a major structural subunit, known as CsgA. CsgA self-assembly is promoted by oligomeric nuclei formed by a minor curli subunit, known as the CsgB nucleator protein. Here, by implementing AMYLPRED2, a consensus prediction method for the identification of 'aggregation-prone' regions in protein sequences, developed in our laboratory, we have successfully identified potent amyloidogenic regions of the CsgB subunit. Peptide-analogues corresponding to the predicted 'aggregation-prone' segments of CsgB were chemically synthesized and studied, utilizing several biophysical techniques. Our experimental data indicate that these peptides self-assemble in solution, forming fibrils with characteristic amyloidogenic properties. Using comparative modeling techniques, we have developed three-dimensional models of both CsgA and CsgB subunits. Structural analysis revealed that the identified 'aggregation-prone' segments may promote gradual polymerization of CsgB. Briefly, our results indicate that the intrinsic self-aggregation propensity of the CsgB subunit, most probably has a pivotal role in initiating the formation of curli amyloid fibers by promoting the self-assembly process of the CsgB nucleator protein.
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Affiliation(s)
- Nikolaos N Louros
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Georgios M P Bolas
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Paraskevi L Tsiolaki
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Stavros J Hamodrakas
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece
| | - Vassiliki A Iconomidou
- Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens 157 01, Greece.
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36
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Abstract
Although prions were first discovered through their link to severe brain degenerative diseases in animals, the emergence of prions as regulators of the phenotype of the yeast Saccharomyces cerevisiae and the filamentous fungus Podospora anserina has revealed a new facet of prion biology. In most cases, fungal prions are carried without apparent detriment to the host cell, representing a novel form of epigenetic inheritance. This raises the question of whether or not yeast prions are beneficial survival factors or actually gives rise to a "disease state" that is selected against in nature. To date, most studies on the impact of fungal prions have focused on laboratory-cultivated "domesticated" strains of S. cerevisiae. At least eight prions have now been described in this species, each with the potential to impact on a wide range of cellular processes. The discovery of prions in nondomesticated strains of S. cerevisiae and P. anserina has confirmed that prions are not simply an artifact of "domestication" of this species. In this review, I describe what we currently know about the phenotypic impact of fungal prions. I then describe how the interplay between host genotype and the prion-mediated changes can generate a wide array of phenotypic diversity. How such prion-generated diversity may be of benefit to the host in survival in a fluctuating, often hazardous environment is then outlined. Prion research has now entered a new phase in which we must now consider their biological function and evolutionary significance in the natural world.
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Affiliation(s)
- Mick F Tuite
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury, Kent CT2 7NJ, United Kingdom.
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37
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Tang W, Bhatt A, Smith AN, Crowley PJ, Brady LJ, Long JR. Specific binding of a naturally occurring amyloidogenic fragment of Streptococcus mutans adhesin P1 to intact P1 on the cell surface characterized by solid state NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2016; 64:153-64. [PMID: 26837620 PMCID: PMC4756430 DOI: 10.1007/s10858-016-0017-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 01/24/2016] [Indexed: 06/05/2023]
Abstract
The P1 adhesin (aka Antigen I/II or PAc) of the cariogenic bacterium Streptococcus mutans is a cell surface-localized protein involved in sucrose-independent adhesion and colonization of the tooth surface. The immunoreactive and adhesive properties of S. mutans suggest an unusual functional quaternary ultrastructure comprised of intact P1 covalently attached to the cell wall and interacting with non-covalently associated proteolytic fragments thereof, particularly the ~57-kDa C-terminal fragment C123 previously identified as Antigen II. S. mutans is capable of amyloid formation when grown in a biofilm and P1 is among its amyloidogenic proteins. The C123 fragment of P1 readily forms amyloid fibers in vitro suggesting it may play a role in the formation of functional amyloid during biofilm development. Using wild-type and P1-deficient strains of S. mutans, we demonstrate that solid state NMR (ssNMR) spectroscopy can be used to (1) globally characterize cell walls isolated from a Gram-positive bacterium and (2) characterize the specific binding of heterologously expressed, isotopically-enriched C123 to cell wall-anchored P1. Our results lay the groundwork for future high-resolution characterization of the C123/P1 ultrastructure and subsequent steps in biofilm formation via ssNMR spectroscopy, and they support an emerging model of S. mutans colonization whereby quaternary P1-C123 interactions confer adhesive properties important to binding to immobilized human salivary agglutinin.
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Affiliation(s)
- Wenxing Tang
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Avni Bhatt
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Adam N Smith
- Department of Chemistry, College of Liberal Arts and Sciences, University of Florida, Gainesville, FL, USA
| | - Paula J Crowley
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - L Jeannine Brady
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA.
| | - Joanna R Long
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL, USA.
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38
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Payne DE, Boles BR. Emerging interactions between matrix components during biofilm development. Curr Genet 2015; 62:137-41. [PMID: 26515441 PMCID: PMC4723619 DOI: 10.1007/s00294-015-0527-5] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 10/13/2015] [Accepted: 10/14/2015] [Indexed: 02/06/2023]
Abstract
Bacterial cells are most often found in the form of multicellular aggregates commonly referred to as biofilms. Biofilms offer their member cells several benefits, such as resistance to killing by antimicrobials and predation. During biofilm formation there is a production of extracellular substances that, upon assembly, constitute an extracellular matrix. The ability to generate a matrix encasing the microbial cells is a common feature of biofilms, but there is diversity in matrix composition and in interaction between matrix components. The different components of bacterial biofilm extracellular matrixes, known as matrix interactions, and resulting implications are discussed in this review.
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Affiliation(s)
- David E Payne
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Blaise R Boles
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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Iglesias V, de Groot NS, Ventura S. Computational analysis of candidate prion-like proteins in bacteria and their role. Front Microbiol 2015; 6:1123. [PMID: 26528269 PMCID: PMC4606120 DOI: 10.3389/fmicb.2015.01123] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/28/2015] [Indexed: 12/02/2022] Open
Abstract
Prion proteins were initially associated with diseases such as Creutzfeldt Jakob and transmissible spongiform encephalopathies. However, deeper research revealed them as versatile tools, exploited by the cells to execute fascinating functions, acting as epigenetic elements or building membrane free compartments in eukaryotes. One of the most intriguing properties of prion proteins is their ability to propagate a conformational assembly, even across species. In this context, it has been observed that bacterial amyloids can trigger the formation of protein aggregates by interacting with host proteins. As our life is closely linked to bacteria, either through a parasitic or symbiotic relationship, prion-like proteins produced by bacterial cells might play a role in this association. Bioinformatics is helping us to understand the factors that determine conformational conversion and infectivity in prion-like proteins. We have used PrionScan to detect prion domains in 839 different bacteria proteomes, detecting 2200 putative prions in these organisms. We studied this set of proteins in order to try to understand their functional role and structural properties. Our results suggest that these bacterial polypeptides are associated to peripheral rearrangement, macromolecular assembly, cell adaptability, and invasion. Overall, these data could reveal new threats and therapeutic targets associated to infectious diseases.
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Affiliation(s)
- Valentin Iglesias
- Departament de Bioquìmica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Natalia S de Groot
- Departament de Bioquìmica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
| | - Salvador Ventura
- Departament de Bioquìmica i Biologia Molecular, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona Barcelona, Spain
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40
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Schwartz K, Ganesan M, Payne DE, Solomon MJ, Boles BR. Extracellular DNA facilitates the formation of functional amyloids in Staphylococcus aureus biofilms. Mol Microbiol 2015; 99:123-34. [PMID: 26365835 DOI: 10.1111/mmi.13219] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/09/2015] [Indexed: 11/27/2022]
Abstract
Persistent staphylococcal infections often involve surface-associated communities called biofilms. Staphylococcus aureus biofilm development is mediated by the co-ordinated production of the biofilm matrix, which can be composed of polysaccharides, extracellular DNA (eDNA) and proteins including amyloid fibers. The nature of the interactions between matrix components, and how these interactions contribute to the formation of matrix, remain unclear. Here we show that the presence of eDNA in S. aureus biofilms promotes the formation of amyloid fibers. Conditions or mutants that do not generate eDNA result in lack of amyloids during biofilm growth despite the amyloidogeneic subunits, phenol soluble modulin peptides, being produced. In vitro studies revealed that the presence of DNA promotes amyloid formation by PSM peptides. Thus, this work exposes a previously unacknowledged interaction between biofilm matrix components that furthers our understanding of functional amyloid formation and S. aureus biofilm biology.
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Affiliation(s)
- Kelly Schwartz
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Mahesh Ganesan
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - David E Payne
- Department of Molecular Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.,Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael J Solomon
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Blaise R Boles
- Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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41
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Prediction of Peptide and Protein Propensity for Amyloid Formation. PLoS One 2015; 10:e0134679. [PMID: 26241652 PMCID: PMC4524629 DOI: 10.1371/journal.pone.0134679] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/13/2015] [Indexed: 11/19/2022] Open
Abstract
Understanding which peptides and proteins have the potential to undergo amyloid formation and what driving forces are responsible for amyloid-like fiber formation and stabilization remains limited. This is mainly because proteins that can undergo structural changes, which lead to amyloid formation, are quite diverse and share no obvious sequence or structural homology, despite the structural similarity found in the fibrils. To address these issues, a novel approach based on recursive feature selection and feed-forward neural networks was undertaken to identify key features highly correlated with the self-assembly problem. This approach allowed the identification of seven physicochemical and biochemical properties of the amino acids highly associated with the self-assembly of peptides and proteins into amyloid-like fibrils (normalized frequency of β-sheet, normalized frequency of β-sheet from LG, weights for β-sheet at the window position of 1, isoelectric point, atom-based hydrophobic moment, helix termination parameter at position j+1 and ΔG° values for peptides extrapolated in 0 M urea). Moreover, these features enabled the development of a new predictor (available at http://cran.r-project.org/web/packages/appnn/index.html) capable of accurately and reliably predicting the amyloidogenic propensity from the polypeptide sequence alone with a prediction accuracy of 84.9 % against an external validation dataset of sequences with experimental in vitro, evidence of amyloid formation.
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Abstract
Amyloids are insoluble fibrillar protein deposits with an underlying cross-β structure initially discovered in the context of human diseases. However, it is now clear that the same fibrillar structure is used by many organisms, from bacteria to humans, in order to achieve a diverse range of biological functions. These functions include structure and protection (e.g. curli and chorion proteins, and insect and spider silk proteins), aiding interface transitions and cell-cell recognition (e.g. chaplins, rodlins and hydrophobins), protein control and storage (e.g. Microcin E492, modulins and PMEL), and epigenetic inheritance and memory [e.g. Sup35, Ure2p, HET-s and CPEB (cytoplasmic polyadenylation element-binding protein)]. As more examples of functional amyloid come to light, the list of roles associated with functional amyloids has continued to expand. More recently, amyloids have also been implicated in signal transduction [e.g. RIP1/RIP3 (receptor-interacting protein)] and perhaps in host defence [e.g. aDrs (anionic dermaseptin) peptide]. The present chapter discusses in detail functional amyloids that are used in Nature by micro-organisms, non-mammalian animals and mammals, including the biological roles that they play, their molecular composition and how they assemble, as well as the coping strategies that organisms have evolved to avoid the potential toxicity of functional amyloid.
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Evans ML, Chorell E, Taylor JD, Åden J, Götheson A, Li F, Koch M, Sefer L, Matthews SJ, Wittung-Stafshede P, Almqvist F, Chapman MR. The bacterial curli system possesses a potent and selective inhibitor of amyloid formation. Mol Cell 2015; 57:445-55. [PMID: 25620560 PMCID: PMC4320674 DOI: 10.1016/j.molcel.2014.12.025] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/28/2014] [Accepted: 12/16/2014] [Indexed: 12/22/2022]
Abstract
Curli are extracellular functional amyloids that are assembled by enteric bacteria during biofilm formation and host colonization. An efficient secretion system and chaperone network ensures that the major curli fiber subunit, CsgA, does not form intracellular amyloid aggregates. We discovered that the periplasmic protein CsgC was a highly effective inhibitor of CsgA amyloid formation. In the absence of CsgC, CsgA formed toxic intracellular aggregates. In vitro, CsgC inhibited CsgA amyloid formation at substoichiometric concentrations and maintained CsgA in a non-β-sheet-rich conformation. Interestingly, CsgC inhibited amyloid assembly of human α-synuclein, but not Aβ42, in vitro. We identified a common D-Q-Φ-X0,1-G-K-N-ζ-E motif in CsgC client proteins that is not found in Aβ42. CsgC is therefore both an efficient and selective amyloid inhibitor. Dedicated functional amyloid inhibitors may be a key feature that distinguishes functional amyloids from disease-associated amyloids.
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Affiliation(s)
- Margery L Evans
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Erik Chorell
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Jonathan D Taylor
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Jörgen Åden
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Anna Götheson
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Fei Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Marion Koch
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Lea Sefer
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | - Steve J Matthews
- Department of Life Sciences, Faculty of Natural Sciences, Imperial College London, London SW7 2AZ, UK
| | | | - Fredrik Almqvist
- Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden; Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Matthew R Chapman
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA; Centre for Microbial Research, Umeå University, 901 87 Umeå, Sweden.
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44
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Chimileski S, Franklin MJ, Papke RT. Biofilms formed by the archaeon Haloferax volcanii exhibit cellular differentiation and social motility, and facilitate horizontal gene transfer. BMC Biol 2014; 12:65. [PMID: 25124934 PMCID: PMC4180959 DOI: 10.1186/s12915-014-0065-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 07/31/2014] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Archaea share a similar microbial lifestyle with bacteria, and not surprisingly then, also exist within matrix-enclosed communities known as biofilms. Advances in biofilm biology have been made over decades for model bacterial species, and include characterizations of social behaviors and cellular differentiation during biofilm development. Like bacteria, archaea impact ecological and biogeochemical systems. However, the biology of archaeal biofilms is only now being explored. Here, we investigated the development, composition and dynamics of biofilms formed by the haloarchaeon Haloferax volcanii DS2. RESULTS Biofilms were cultured in static liquid and visualized with fluorescent cell membrane dyes and by engineering cells to express green fluorescent protein (GFP). Analysis by confocal scanning laser microscopy showed that H. volcanii cells formed microcolonies within 24 h, which developed into larger clusters by 48 h and matured into flake-like towers often greater than 100 μm in height after 7 days. To visualize the extracellular matrix, biofilms formed by GFP-expressing cells were stained with concanavalin A, DAPI, Congo red and thioflavin T. Stains colocalized with larger cellular structures and indicated that the extracellular matrix may contain a combination of polysaccharides, extracellular DNA and amyloid protein. Following a switch to biofilm growth conditions, a sub-population of cells differentiated into chains of long rods sometimes exceeding 25 μm in length, compared to their planktonic disk-shaped morphology. Time-lapse photography of static liquid biofilms also revealed wave-like social motility. Finally, we quantified gene exchange between biofilm cells, and found that it was equivalent to the mating frequency of a classic filter-based experimental method. CONCLUSIONS The developmental processes, functional properties and dynamics of H. volcanii biofilms provide insight on how haloarchaeal species might persist, interact and exchange DNA in natural communities. H. volcanii demonstrates some biofilm phenotypes similar to bacterial biofilms, but also has interesting phenotypes that may be unique to this organism or to this class of organisms, including changes in cellular morphology and an unusual form of social motility. Because H. volcanii has one of the most advanced genetic systems for any archaeon, the phenotypes reported here may promote the study of genetic and developmental processes in archaeal biofilms.
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45
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The AgrD N-terminal leader peptide of Staphylococcus aureus has cytolytic and amyloidogenic properties. Infect Immun 2014; 82:3837-44. [PMID: 24980969 DOI: 10.1128/iai.02111-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Staphylococcus aureus virulence is coordinated through the Agr quorum-sensing system to produce an array of secreted molecules. One important class of secreted virulence factors is the phenol-soluble modulins (PSMs). PSMs are small-peptide toxins that have recently been characterized for their roles in infection, biofilm development, and subversion of the host immune system. In this work, we demonstrate that the signal peptide of the S. aureus quorum-sensing signal, AgrD, shares structural and functional similarities with the PSM family of toxins. The efficacy of this peptide (termed N-AgrD) beyond AgrD propeptide trafficking has never been described before. We observe that N-AgrD, like the PSMs, is found in the amyloid fibrils of S. aureus biofilms and is capable of forming and seeding amyloid fibrils in vitro. N-AgrD displays cytolytic and proinflammatory properties that are abrogated after fibril formation. These data suggest that the N-AgrD leader peptide affects S. aureus biology in a manner similar to that described previously for the PSM peptide toxins. Taken together, our findings suggest that peptide cleavage products can affect cellular function beyond their canonical roles and may represent a class of virulence factors warranting further exploration.
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46
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Knowles TPJ, Vendruscolo M, Dobson CM. The amyloid state and its association with protein misfolding diseases. Nat Rev Mol Cell Biol 2014; 15:384-96. [PMID: 24854788 DOI: 10.1038/nrm3810] [Citation(s) in RCA: 1622] [Impact Index Per Article: 162.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The phenomenon of protein aggregation and amyloid formation has become the subject of rapidly increasing research activities across a wide range of scientific disciplines. Such activities have been stimulated by the association of amyloid deposition with a range of debilitating medical disorders, from Alzheimer's disease to type II diabetes, many of which are major threats to human health and welfare in the modern world. It has become clear, however, that the ability to form the amyloid state is more general than previously imagined, and that its study can provide unique insights into the nature of the functional forms of peptides and proteins, as well as understanding the means by which protein homeostasis can be maintained and protein metastasis avoided.
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Affiliation(s)
- Tuomas P J Knowles
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Michele Vendruscolo
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Christopher M Dobson
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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47
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Heindl JE, Wang Y, Heckel BC, Mohari B, Feirer N, Fuqua C. Mechanisms and regulation of surface interactions and biofilm formation in Agrobacterium. FRONTIERS IN PLANT SCIENCE 2014; 5:176. [PMID: 24834068 PMCID: PMC4018554 DOI: 10.3389/fpls.2014.00176] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/12/2014] [Indexed: 05/05/2023]
Abstract
For many pathogenic bacteria surface attachment is a required first step during host interactions. Attachment can proceed to invasion of host tissue or cells or to establishment of a multicellular bacterial community known as a biofilm. The transition from a unicellular, often motile, state to a sessile, multicellular, biofilm-associated state is one of the most important developmental decisions for bacteria. Agrobacterium tumefaciens genetically transforms plant cells by transfer and integration of a segment of plasmid-encoded transferred DNA (T-DNA) into the host genome, and has also been a valuable tool for plant geneticists. A. tumefaciens attaches to and forms a complex biofilm on a variety of biotic and abiotic substrates in vitro. Although rarely studied in situ, it is hypothesized that the biofilm state plays an important functional role in the ecology of this organism. Surface attachment, motility, and cell division are coordinated through a complex regulatory network that imparts an unexpected asymmetry to the A. tumefaciens life cycle. In this review, we describe the mechanisms by which A. tumefaciens associates with surfaces, and regulation of this process. We focus on the transition between flagellar-based motility and surface attachment, and on the composition, production, and secretion of multiple extracellular components that contribute to the biofilm matrix. Biofilm formation by A. tumefaciens is linked with virulence both mechanistically and through shared regulatory molecules. We detail our current understanding of these and other regulatory schemes, as well as the internal and external (environmental) cues mediating development of the biofilm state, including the second messenger cyclic-di-GMP, nutrient levels, and the role of the plant host in influencing attachment and biofilm formation. A. tumefaciens is an important model system contributing to our understanding of developmental transitions, bacterial cell biology, and biofilm formation.
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Affiliation(s)
| | | | | | | | | | - Clay Fuqua
- Department of Biology, Indiana University, BloomingtonIN, USA
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48
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Aggregation interplay between variants of the RepA-WH1 prionoid in Escherichia coli. J Bacteriol 2014; 196:2536-42. [PMID: 24794561 DOI: 10.1128/jb.01527-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The N-terminal domain (winged-helix domain, or WH1) of the Pseudomonas pPS10 plasmid DNA replication protein RepA can assemble into amyloid fibers in vitro and, when expressed in Escherichia coli, leads to a unique intracellular amyloid proteinopathy by hampering bacterial proliferation. RepA-WH1 amyloidosis propagates along generations through the transmission of aggregated particles across the progeny, but it is unable to propagate horizontally as an infectious agent and is thus the first synthetic bacterial prionoid. RepA-WH1 amyloidosis is promoted by binding to double-stranded DNA (dsDNA) in vitro, and it is modulated by the Hsp70 chaperone DnaK in vivo. Different mutations in the repA-WH1 gene result in variants of the protein with distinct amyloidogenic properties. Here, we report that intracellular aggregates of the hyperamyloidogenic RepA with an A31V change in WH1 [RepA-WH1(A31V)] are able to induce and enhance the growth in vivo of new amyloid particles from molecules of wild-type RepA-WH1 [RepA-WH1(WT)], which otherwise would remain soluble in the cytoplasm. In contrast, RepA-WH1(ΔN37), a variant lacking a clear amyloidogenic sequence stretch that aggregates as conventional inclusion bodies (IBs), can drive the aggregation of the soluble protein into IBs only if expressed at high molar ratios over RepA-WH1(WT). The cytotoxic bacterial intracellular prionoid RepA-WH1 thus exhibits a hallmark feature of amyloids, as characterized in eukaryotes: cross-aggregation between variants of the same protein.
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49
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Advanced techniques for in situ analysis of the biofilm matrix (structure, composition, dynamics) by means of laser scanning microscopy. Methods Mol Biol 2014; 1147:43-64. [PMID: 24664825 DOI: 10.1007/978-1-4939-0467-9_4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The extracellular constituents in bioaggregates and biofilms can be imaged four dimensionally by using laser scanning microscopy. In this protocol we provide guidance on how to examine the various extracellular compartments in between microbial cells and communities associated with interfaces. The current options for fluorescence staining of matrix compounds and extracellular microhabitats are presented. Furthermore, practical aspects are discussed and useful notes are added. The chapter ends with a brief introduction to other approaches for EPS analysis and an outlook for future needs.
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50
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Ren Q, Kwan AH, Sunde M. Two forms and two faces, multiple states and multiple uses: Properties and applications of the self-assembling fungal hydrophobins. Biopolymers 2013; 100:601-12. [DOI: 10.1002/bip.22259] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/08/2013] [Indexed: 01/20/2023]
Affiliation(s)
- Qin Ren
- Discipline of Pharmacology, School of Medical Sciences; University of Sydney; New South Wales 2006 Australia
| | - Ann H. Kwan
- School of Molecular Bioscience; University of Sydney; New South Wales 2006 Australia
| | - Margaret Sunde
- Discipline of Pharmacology, School of Medical Sciences; University of Sydney; New South Wales 2006 Australia
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