1
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Graham LA, Hansen T, Yang Y, Sherik M, Ye Q, Soares BP, Kinrade B, Guo S, Davies PL. Adhesin domains responsible for binding bacteria to surfaces they colonize project outwards from companion split domains. Proteins 2024; 92:933-945. [PMID: 38591850 DOI: 10.1002/prot.26689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/07/2024] [Accepted: 03/26/2024] [Indexed: 04/10/2024]
Abstract
Bacterial adhesins attach their hosts to surfaces that the bacteria will colonize. This surface adhesion occurs through specific ligand-binding domains located towards the distal end of the long adhesin molecules. However, recognizing which of the many adhesin domains are structural and which are ligand binding has been difficult up to now. Here we have used the protein structure modeling program AlphaFold2 to predict structures for these giant 0.2- to 1.5-megadalton proteins. Crystal structures previously solved for several adhesin regions are in good agreement with the models. Whereas most adhesin domains are linked in a linear fashion through their N- and C-terminal ends, ligand-binding domains can be recognized by budding out from a companion core domain so that their ligand-binding sites are projected away from the axis of the adhesin for maximal exposure to their targets. These companion domains are "split" in their continuity by projecting the ligand-binding domain outwards. The "split domains" are mostly β-sandwich extender modules, but other domains like a β-solenoid can serve the same function. Bioinformatic analyses of Gram-negative bacterial sequences revealed wide variety ligand-binding domains are used in their Repeats-in-Toxin adhesins. The ligands for many of these domains have yet to be identified but known ligands include various cell-surface glycans, proteins, and even ice. Recognizing the ligands to which the adhesins bind could lead to ways of blocking colonization by bacterial pathogens. Engineering different ligand-binding domains into an adhesin has the potential to change the surfaces to which bacteria bind.
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Affiliation(s)
- Laurie A Graham
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Thomas Hansen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Yanzhi Yang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Mustafa Sherik
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Qilu Ye
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Blake P Soares
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Brett Kinrade
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Shuaiqi Guo
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
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2
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Khoury F, Su Z, Banta S. Rare Earth Element Binding and Recovery by a Beta Roll-Forming RTX Domain. Inorg Chem 2024; 63:13223-13230. [PMID: 38986039 DOI: 10.1021/acs.inorgchem.4c00420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024]
Abstract
The Block V of the RTX domain of the adenylate cyclase protein from Bordetella pertussis is disordered, and upon binding eight calcium ions, it folds into a beta roll domain with a C-terminal capping group. Due to their similar ionic radii and coordination geometries, trivalent lanthanide ions have been used to probe and identify calcium-binding sites in many proteins. Here, we report using a FRET-based assay that the RTX domain can bind rare earth elements (REEs) with higher affinities than calcium. The apparent disassociation constants for lanthanide ions ranged from 20 to 75 μM, which are an order of magnitude higher than the affinity for calcium, with a higher selectivity toward heavy REEs over light REEs. Most proteins release bound ions at mildly acidic conditions (pH 5-6), and the high affinity REE-binding lanmodulin protein can bind 3-4 REE ions at pH as low as ∼2.5. Circular dichroism (CD) spectra of the RTX domain demonstrate pH-induced folding of the beta roll domain in the absence of ions, indicating that protonation of key amino acids enables structure formation in low pH solutions. The beta roll domain coordinates up to four ions in extreme pH conditions (pH < 1), as determined by equilibrium ultrafiltration experiments. Finally, to demonstrate a potential application of the RTX domain, REE ions (Nd3+ and Dy3+) were recovered from other non-REEs (Fe2+ and Co2+) in a NdFeB magnet simulant solution (at pH 6).
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Affiliation(s)
- Farid Khoury
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Zihang Su
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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3
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Abettan A, Nguyen MH, Ladant D, Monticelli L, Chenal A. CyaA translocation across eukaryotic cell membranes. Front Mol Biosci 2024; 11:1359408. [PMID: 38584704 PMCID: PMC10995232 DOI: 10.3389/fmolb.2024.1359408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 01/23/2024] [Indexed: 04/09/2024] Open
Affiliation(s)
- Amiel Abettan
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Molecular Microbiology and Structural Biochemistry Laboratory, CNRS UMR 5086, University of Lyon, IBCP, Lyon, France
| | - Minh-Ha Nguyen
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Université de Paris Cité, Paris, France
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biological NMR and HDX-MS Technological Platform, Paris, France
| | - Daniel Ladant
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Université de Paris Cité, Paris, France
| | - Luca Monticelli
- Molecular Microbiology and Structural Biochemistry Laboratory, CNRS UMR 5086, University of Lyon, IBCP, Lyon, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), Lyon, France
| | - Alexandre Chenal
- Institut Pasteur, Université de Paris Cité, CNRS UMR3528, Biochemistry of Macromolecular Interactions Unit, Paris, France
- Université de Paris Cité, Paris, France
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4
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Agaras BC, Grossi CEM, Ulloa RM. Unveiling the Secrets of Calcium-Dependent Proteins in Plant Growth-Promoting Rhizobacteria: An Abundance of Discoveries Awaits. PLANTS (BASEL, SWITZERLAND) 2023; 12:3398. [PMID: 37836138 PMCID: PMC10574481 DOI: 10.3390/plants12193398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/20/2023] [Accepted: 09/22/2023] [Indexed: 10/15/2023]
Abstract
The role of Calcium ions (Ca2+) is extensively documented and comprehensively understood in eukaryotic organisms. Nevertheless, emerging insights, primarily derived from studies on human pathogenic bacteria, suggest that this ion also plays a pivotal role in prokaryotes. In this review, our primary focus will be on unraveling the intricate Ca2+ toolkit within prokaryotic organisms, with particular emphasis on its implications for plant growth-promoting rhizobacteria (PGPR). We undertook an in silico exploration to pinpoint and identify some of the proteins described in the existing literature, including prokaryotic Ca2+ channels, pumps, and exchangers that are responsible for regulating intracellular Calcium concentration ([Ca2+]i), along with the Calcium-binding proteins (CaBPs) that play a pivotal role in sensing and transducing this essential cation. These investigations were conducted in four distinct PGPR strains: Pseudomonas chlororaphis subsp. aurantiaca SMMP3, P. donghuensis SVBP6, Pseudomonas sp. BP01, and Methylobacterium sp. 2A, which have been isolated and characterized within our research laboratories. We also present preliminary experimental data to evaluate the influence of exogenous Ca2+ concentrations ([Ca2+]ex) on the growth dynamics of these strains.
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Affiliation(s)
- Betina Cecilia Agaras
- Laboratory of Physiology and Genetics of Plant Probiotic Bacteria (LFGBBP), Centre of Biochemistry and Microbiology of Soils, National University of Quilmes, Bernal B1876BXD, Argentina
- National Scientific and Technical Research Council (CONICET), Buenos Aires C1425FQB, Argentina;
| | - Cecilia Eugenia María Grossi
- National Scientific and Technical Research Council (CONICET), Buenos Aires C1425FQB, Argentina;
- Laboratory of Plant Signal Transduction, Institute of Genetic Engineering and Molecular Biology (INGEBI), National Scientific and Technical Research Council (CONICET), Buenos Aires C1425FQB, Argentina
| | - Rita María Ulloa
- National Scientific and Technical Research Council (CONICET), Buenos Aires C1425FQB, Argentina;
- Laboratory of Plant Signal Transduction, Institute of Genetic Engineering and Molecular Biology (INGEBI), National Scientific and Technical Research Council (CONICET), Buenos Aires C1425FQB, Argentina
- Biochemistry Department, Faculty of Exact and Natural Sciences, University of Buenos Aires (FCEN-UBA), Buenos Aires C1428EGA, Argentina
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5
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Chen G, Wang H, Bumba L, Masin J, Sebo P, Li H. The adenylate cyclase toxin RTX domain follows a series templated folding mechanism with implications for toxin activity. J Biol Chem 2023; 299:105150. [PMID: 37567473 PMCID: PMC10511787 DOI: 10.1016/j.jbc.2023.105150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/26/2023] [Accepted: 08/07/2023] [Indexed: 08/13/2023] Open
Abstract
Folding of the Repeats-in-toxin (RTX) domain of the bacterial adenylate cyclase toxin-hemolysin (CyaA) is critical to its toxin activities and the virulence of the whooping cough agent Bordetella pertussis. The RTX domain (RD) contains five RTX blocks (RTX-i to RTX-v) and their folding is driven by the binding of calcium. However, the detailed molecular mechanism via which the folding signal transmits within the five RTX blocks remains unknown. By combining single molecule optical tweezers, protein engineering, and toxin activity assays, here we demonstrate that the folding of the RD follows a strict hierarchy, with the folding starting from its C-terminal block RTX-v and proceeding towards the N-terminal RTX-i block sequentially. Our results reveal a strict series, templated folding mechanism, where the folding signal is transmitted along the RD in a series fashion from its C terminus continuously to the N terminus. Due to the series nature of this folding signal transmission pathway, the folding of RD can be disrupted at any given RTX block, rendering the RTX blocks located N-terminally to the disruption site and the acylation region of CyaA unfolded and abolishing CyaA's toxin activities. Our results reveal key mechanistic insights into the secretion and folding process of CyaA and may open up new potential avenues towards designing new therapeutics to abolish toxin activity of CyaA and combat B. pertussis.
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Affiliation(s)
- Guojun Chen
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Han Wang
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Jiri Masin
- Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prague, Czech Republic
| | - Hongbin Li
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada.
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Locht C. Pasteurian Contributions to the Study of Bordetella pertussis Toxins. Toxins (Basel) 2023; 15:toxins15030176. [PMID: 36977067 PMCID: PMC10054083 DOI: 10.3390/toxins15030176] [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: 01/31/2023] [Revised: 02/17/2023] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
As a tribute to Louis Pasteur on the occasion of the 200th anniversary of his birth, this article summarizes the main contributions of scientists from Pasteur Institutes to the current knowledge of toxins produced by Bordetella pertussis. The article therefore focuses on publications authored by researchers from Pasteur Institutes and is not intended as a systematic review of B. pertussis toxins. Besides identifying B. pertussis as the causative agent of whooping cough, Pasteurians have made several major contributions with respect to the structure–function relationship of the Bordetella lipo-oligosaccharide, adenylyl cyclase toxin and pertussis toxin. In addition to contributing to the understanding of these toxins’ mechanisms at the molecular and cellular levels and their role in pathogenesis, scientists at Pasteur Institutes have also exploited potential applications of the gathered knowledge of these toxins. These applications range from the development of novel tools to study protein–protein interactions over the design of novel antigen delivery tools, such as prophylactic or therapeutic vaccine candidates against cancer and viral infection, to the development of a live attenuated nasal pertussis vaccine. This scientific journey from basic science to applications in the field of human health matches perfectly with the overall scientific objectives outlined by Louis Pasteur himself.
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Affiliation(s)
- Camille Locht
- Univ. Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Centre for Infection and Immunity of Lille, F-59000 Lille, France
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7
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Hodges FJ, Torres VVL, Cunningham AF, Henderson IR, Icke C. Redefining the bacterial Type I protein secretion system. Adv Microb Physiol 2023; 82:155-204. [PMID: 36948654 DOI: 10.1016/bs.ampbs.2022.10.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Type I secretion systems (T1SS) are versatile molecular machines for protein transport across the Gram-negative cell envelope. The archetypal Type I system mediates secretion of the Escherichia coli hemolysin, HlyA. This system has remained the pre-eminent model of T1SS research since its discovery. The classic description of a T1SS is composed of three proteins: an inner membrane ABC transporter, a periplasmic adaptor protein and an outer membrane factor. According to this model, these components assemble to form a continuous channel across the cell envelope, an unfolded substrate molecule is then transported in a one-step mechanism, directly from the cytosol to the extracellular milieu. However, this model does not encapsulate the diversity of T1SS that have been characterized to date. In this review, we provide an updated definition of a T1SS, and propose the subdivision of this system into five subgroups. These subgroups are categorized as T1SSa for RTX proteins, T1SSb for non-RTX Ca2+-binding proteins, T1SSc for non-RTX proteins, T1SSd for class II microcins, and T1SSe for lipoprotein secretion. Although often overlooked in the literature, these alternative mechanisms of Type I protein secretion offer many avenues for biotechnological discovery and application.
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Affiliation(s)
- Freya J Hodges
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Von Vergel L Torres
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia
| | - Adam F Cunningham
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Ian R Henderson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
| | - Christopher Icke
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
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8
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Filipi K, Rahman WU, Osickova A, Osicka R. Kingella kingae RtxA Cytotoxin in the Context of Other RTX Toxins. Microorganisms 2022; 10:518. [PMID: 35336094 PMCID: PMC8953716 DOI: 10.3390/microorganisms10030518] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 12/04/2022] Open
Abstract
The Gram-negative bacterium Kingella kingae is part of the commensal oropharyngeal flora of young children. As detection methods have improved, K. kingae has been increasingly recognized as an emerging invasive pathogen that frequently causes skeletal system infections, bacteremia, and severe forms of infective endocarditis. K. kingae secretes an RtxA cytotoxin, which is involved in the development of clinical infection and belongs to an ever-growing family of cytolytic RTX (Repeats in ToXin) toxins secreted by Gram-negative pathogens. All RTX cytolysins share several characteristic structural features: (i) a hydrophobic pore-forming domain in the N-terminal part of the molecule; (ii) an acylated segment where the activation of the inactive protoxin to the toxin occurs by a co-expressed toxin-activating acyltransferase; (iii) a typical calcium-binding RTX domain in the C-terminal portion of the molecule with the characteristic glycine- and aspartate-rich nonapeptide repeats; and (iv) a C-proximal secretion signal recognized by the type I secretion system. RTX toxins, including RtxA from K. kingae, have been shown to act as highly efficient 'contact weapons' that penetrate and permeabilize host cell membranes and thus contribute to the pathogenesis of bacterial infections. RtxA was discovered relatively recently and the knowledge of its biological role remains limited. This review describes the structure and function of RtxA in the context of the most studied RTX toxins, the knowledge of which may contribute to a better understanding of the action of RtxA in the pathogenesis of K. kingae infections.
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Affiliation(s)
| | | | | | - Radim Osicka
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, Czech Republic; (K.F.); (W.U.R.); (A.O.)
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Quantification and surface localization of the hemolysin A type 1 secretion system at the endogenous level and under conditions of overexpression. Appl Environ Microbiol 2021; 88:e0189621. [PMID: 34851699 DOI: 10.1128/aem.01896-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Secretion systems are essential for Gram-negative bacteria as these nanomachineries allow a communication with the outside world by exporting proteins into the extracellular space or directly into the cytosol of a host cell. For example, type one secretion systems (T1SS) secrete a broad range of substrates across both membranes into the extracellular space. One well-known example is the hemolysin A (HlyA) T1SS from Escherichia coli (E. coli), which consists of an ABC transporter (HlyB), a membrane fusion protein (HlyD), the outer membrane protein TolC and the substrate HlyA, a member of the family of RTX (repeats in toxins) toxins. Here, we determined the amount of TolC at the endogenous level (parental strain, UTI89) and under conditions of overexpression (T7 expression system, BL21(DE3)-BD). The overall amount of TolC was not influenced by the overexpression of the HlyBD complex. Moving one step further, we determined the localization of the HlyA T1SS by super-resolution microscopy. In contrast to other bacterial secretion systems, no polarization was observed with respect to endogenous or overexpression levels. Additionally, the cell growth and division cycle did not influence the polarization. Most importantly, the size of the observed T1SS clusters did not correlate with the recently proposed outer membrane islands. These data indicate that T1SS cluster at the outer membrane generating domains of so far not described identity. Importance Uropathogenic Escherichia coli (UPEC) strains cause about 110 million urinary tract infections each year worldwide representing a global burden to the healthcare system. UPEC secrete many virulence factors among these the TX toxin hemolysin A via a cognate T1SS into the extracellular space. In this study, we determined the endogenous copy number of the HlyA T1SS in UTI89 and analyzed the surface localization in BL21(DE3)-BD and UTI89, respectively. With approximately 800 copies of the T1SS in UTI89, this is one of the highest expressed bacterial secretion systems. Furthermore and in clear contrast to other secretion systems, no polarized surface localization was detected. Finally, quantitative analysis of the super-resolution data revealed that clusters of the HlyA T1SS are not related to the recently identified outer membrane protein islands. These data provide insights into the quantitative molecular architecture of the HlyA T1SS.
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10
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Chang MP, Huang W, Mai DJ. Monomer‐scale design of functional protein polymers using consensus repeat sequences. JOURNAL OF POLYMER SCIENCE 2021. [DOI: 10.1002/pol.20210506] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Marina P. Chang
- Department of Materials Science and Engineering Stanford University Stanford California USA
| | - Winnie Huang
- Department of Chemical Engineering Stanford University Stanford California USA
| | - Danielle J. Mai
- Department of Chemical Engineering Stanford University Stanford California USA
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Structural basis for antibody binding to adenylate cyclase toxin reveals RTX linkers as neutralization-sensitive epitopes. PLoS Pathog 2021; 17:e1009920. [PMID: 34547035 PMCID: PMC8486122 DOI: 10.1371/journal.ppat.1009920] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/01/2021] [Accepted: 08/27/2021] [Indexed: 11/19/2022] Open
Abstract
RTX leukotoxins are a diverse family of prokaryotic virulence factors that are secreted by the type 1 secretion system (T1SS) and target leukocytes to subvert host defenses. T1SS substrates all contain a C-terminal RTX domain that mediates recruitment to the T1SS and drives secretion via a Brownian ratchet mechanism. Neutralizing antibodies against the Bordetella pertussis adenylate cyclase toxin, an RTX leukotoxin essential for B. pertussis colonization, have been shown to target the RTX domain and prevent binding to the αMβ2 integrin receptor. Knowledge of the mechanisms by which antibodies bind and neutralize RTX leukotoxins is required to inform structure-based design of bacterial vaccines, however, no structural data are available for antibody binding to any T1SS substrate. Here, we determine the crystal structure of an engineered RTX domain fragment containing the αMβ2-binding site bound to two neutralizing antibodies. Notably, the receptor-blocking antibodies bind to the linker regions of RTX blocks I–III, suggesting they are key neutralization-sensitive sites within the RTX domain and are likely involved in binding the αMβ2 receptor. As the engineered RTX fragment contained these key epitopes, we assessed its immunogenicity in mice and showed that it elicits similar neutralizing antibody titers to the full RTX domain. The results from these studies will support the development of bacterial vaccines targeting RTX leukotoxins, as well as next-generation B. pertussis vaccines. Diverse bacterial pathogens use the type 1 secretion system (T1SS) to secrete RTX leukotoxins, which target host leukocytes during infection. T1SS substrates all contain a repetitive C-terminal ‘RTX’ domain that adopts a characteristic β-roll fold and is involved in secretion. Notably, The RTX domain of Bordetella pertussis adenylate cyclase toxin (ACT) mediates leukocyte targeting via binding to the αMβ2 integrin receptor, and antibodies that block receptor binding neutralize toxin activity. However, ACT also contains multiple non-neutralizing epitopes, and precise knowledge of the sites targeted by neutralizing antibodies is desirable for vaccine design. Here we determine the crystal structure of an ACT fragment in complex with two neutralizing antibodies and define the key neutralization-sensitive sites within the RTX domain. This first structure of a heterotypic protein–protein interaction formed by an RTX domain suggests the linker regions between β-roll segments engage binding partners.
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12
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Lavigne M, Helynck O, Rigolet P, Boudria-Souilah R, Nowakowski M, Baron B, Brülé S, Hoos S, Raynal B, Guittat L, Beauvineau C, Petres S, Granzhan A, Guillon J, Pratviel G, Teulade-Fichou MP, England P, Mergny JL, Munier-Lehmann H. SARS-CoV-2 Nsp3 unique domain SUD interacts with guanine quadruplexes and G4-ligands inhibit this interaction. Nucleic Acids Res 2021; 49:7695-7712. [PMID: 34232992 PMCID: PMC8287907 DOI: 10.1093/nar/gkab571] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 06/15/2021] [Accepted: 06/19/2021] [Indexed: 12/16/2022] Open
Abstract
The multidomain non-structural protein 3 (Nsp3) is the largest protein encoded by coronavirus (CoV) genomes and several regions of this protein are essential for viral replication. Of note, SARS-CoV Nsp3 contains a SARS-Unique Domain (SUD), which can bind Guanine-rich non-canonical nucleic acid structures called G-quadruplexes (G4) and is essential for SARS-CoV replication. We show herein that the SARS-CoV-2 Nsp3 protein also contains a SUD domain that interacts with G4s. Indeed, interactions between SUD proteins and both DNA and RNA G4s were evidenced by G4 pull-down, Surface Plasmon Resonance and Homogenous Time Resolved Fluorescence. These interactions can be disrupted by mutations that prevent oligonucleotides from folding into G4 structures and, interestingly, by molecules known as specific ligands of these G4s. Structural models for these interactions are proposed and reveal significant differences with the crystallographic and modeled 3D structures of the SARS-CoV SUD-NM/G4 interaction. Altogether, our results pave the way for further studies on the role of SUD/G4 interactions during SARS-CoV-2 replication and the use of inhibitors of these interactions as potential antiviral compounds.
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Affiliation(s)
- Marc Lavigne
- Institut Pasteur, Département de Virologie. CNRS UMR 3569, Paris, France
| | - Olivier Helynck
- Institut Pasteur, Unité de Chimie et Biocatalyse. CNRS UMR 3523, Paris, France
| | - Pascal Rigolet
- Institut Curie, Université Paris-Saclay, CNRS UMR 9187, Inserm U1196, Orsay, France
| | | | - Mireille Nowakowski
- Institut Pasteur, Plateforme de Production et Purification de Protéines Recombinantes, C2RT, CNRS UMR 3528, Paris, France
| | - Bruno Baron
- Institut Pasteur, Plateforme de Biophysique Moléculaire, C2RT, CNRS UMR 3528, Paris, France
| | - Sébastien Brülé
- Institut Pasteur, Plateforme de Biophysique Moléculaire, C2RT, CNRS UMR 3528, Paris, France
| | - Sylviane Hoos
- Institut Pasteur, Plateforme de Biophysique Moléculaire, C2RT, CNRS UMR 3528, Paris, France
| | - Bertrand Raynal
- Institut Pasteur, Plateforme de Biophysique Moléculaire, C2RT, CNRS UMR 3528, Paris, France
| | - Lionel Guittat
- Université Sorbonne Paris Nord, INSERM U978, Labex Inflamex, F-93017 Bobigny, France
- Laboratoire d’optique et Biosciences, Ecole Polytechnique, Inserm U1182, CNRS UMR7645, Institut Polytechnique de Paris, Palaiseau, France
| | - Claire Beauvineau
- Institut Curie, Université Paris-Saclay, CNRS UMR 9187, Inserm U1196, Orsay, France
| | - Stéphane Petres
- Institut Pasteur, Plateforme de Production et Purification de Protéines Recombinantes, C2RT, CNRS UMR 3528, Paris, France
| | - Anton Granzhan
- Institut Curie, Université Paris-Saclay, CNRS UMR 9187, Inserm U1196, Orsay, France
| | - Jean Guillon
- Inserm U1212, CNRS UMR 5320, Laboratoire ARNA, UFR des Sciences Pharmaceutiques, Université de Bordeaux, Bordeaux, France
| | - Geneviève Pratviel
- CNRS UPR 8241, Université Paul Sabatier, Laboratoire de Chimie de Coordination, Toulouse, France
| | | | - Patrick England
- Institut Pasteur, Plateforme de Biophysique Moléculaire, C2RT, CNRS UMR 3528, Paris, France
| | - Jean-Louis Mergny
- Laboratoire d’optique et Biosciences, Ecole Polytechnique, Inserm U1182, CNRS UMR7645, Institut Polytechnique de Paris, Palaiseau, France
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González Bullón D, Uribe KB, Amuategi J, Martín C, Ostolaza H. Cholesterol stimulates the lytic activity of Adenylate Cyclase Toxin on lipid membranes by promoting toxin oligomerization and formation of pores with a greater effective size. FEBS J 2021; 288:6795-6814. [PMID: 34216517 PMCID: PMC9290974 DOI: 10.1111/febs.16107] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/27/2021] [Accepted: 07/02/2021] [Indexed: 11/28/2022]
Abstract
Several toxins acting on animal cells present different, but specific, interactions with cholesterol. Bordetella pertussis infects the human respiratory tract and causes whooping cough, a highly contagious and resurgent disease. Its virulence factor adenylate cyclase toxin (ACT) plays an important role in the course of infection. ACT is a pore‐forming cytolysin belonging to the Repeats in ToXin (RTX) family of leukotoxins/hemolysins and is capable of permeabilizing several cell types and lipid vesicles. Previously, we observed that in the presence of cholesterol ACT induces greater liposome permeabilization. Similarly, recent reports also implicate cholesterol in the cytotoxicity of an increasing number of pore‐forming RTX toxins. However, the mechanistic details by which this sterol promotes the lytic activity of ACT or of these other RTX toxins remain largely unexplored and poorly understood. Here, we have applied a combination of biophysical techniques to dissect the role of cholesterol in pore formation by ACT. Our results indicate that cholesterol enhances the lytic potency of ACT by promoting toxin oligomerization, a step which is indispensable for ACT to accomplish membrane permeabilization and cell lysis. Since our experimental design eliminates the possibility that this cholesterol effect derives from toxin accumulation due to lateral lipid phase segregation, we hypothesize that cholesterol facilitates lytic pore formation, by favoring a toxin conformation more prone to protein–protein interactions and oligomerization. Our data shed light on the complex relationship between lipid membranes and protein toxins acting on these membranes. Coupling cholesterol binding, increased oligomerization and increased lytic activity is likely pertinent for other RTX cytolysins.
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Affiliation(s)
- David González Bullón
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - Kepa B Uribe
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - Jone Amuategi
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - César Martín
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
| | - Helena Ostolaza
- Department of Biochemistry and Molecular Biology, Biofisika Institute, (UPV/EHU, CSIC), University of Basque Country (UPV/EHU), Bilbao, Spain
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14
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Voegele A, Sadi M, O'Brien DP, Gehan P, Raoux‐Barbot D, Davi M, Hoos S, Brûlé S, Raynal B, Weber P, Mechaly A, Haouz A, Rodriguez N, Vachette P, Durand D, Brier S, Ladant D, Chenal A. A High-Affinity Calmodulin-Binding Site in the CyaA Toxin Translocation Domain is Essential for Invasion of Eukaryotic Cells. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2003630. [PMID: 33977052 PMCID: PMC8097335 DOI: 10.1002/advs.202003630] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/10/2020] [Indexed: 06/12/2023]
Abstract
The molecular mechanisms and forces involved in the translocation of bacterial toxins into host cells are still a matter of intense research. The adenylate cyclase (CyaA) toxin from Bordetella pertussis displays a unique intoxication pathway in which its catalytic domain is directly translocated across target cell membranes. The CyaA translocation region contains a segment, P454 (residues 454-484), which exhibits membrane-active properties related to antimicrobial peptides. Herein, the results show that this peptide is able to translocate across membranes and to interact with calmodulin (CaM). Structural and biophysical analyses reveal the key residues of P454 involved in membrane destabilization and calmodulin binding. Mutational analysis demonstrates that these residues play a crucial role in CyaA translocation into target cells. In addition, calmidazolium, a calmodulin inhibitor, efficiently blocks CyaA internalization. It is proposed that after CyaA binding to target cells, the P454 segment destabilizes the plasma membrane, translocates across the lipid bilayer and binds calmodulin. Trapping of CyaA by the CaM:P454 interaction in the cytosol may assist the entry of the N-terminal catalytic domain by converting the stochastic motion of the polypeptide chain through the membrane into an efficient vectorial chain translocation into host cells.
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Affiliation(s)
- Alexis Voegele
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
- Université de ParisSorbonne Paris CitéParis75006France
| | - Mirko Sadi
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
- Université de ParisSorbonne Paris CitéParis75006France
| | - Darragh Patrick O'Brien
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Pauline Gehan
- Sorbonne UniversitéÉcole normale supérieurePSL UniversityCNRSLaboratoire des biomoléculesLBMParis75005France
| | - Dorothée Raoux‐Barbot
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Maryline Davi
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Sylviane Hoos
- Plateforme de Biophysique MoléculaireInstitut PasteurUMR 3528 CNRSParis75015France
| | - Sébastien Brûlé
- Plateforme de Biophysique MoléculaireInstitut PasteurUMR 3528 CNRSParis75015France
| | - Bertrand Raynal
- Plateforme de Biophysique MoléculaireInstitut PasteurUMR 3528 CNRSParis75015France
| | - Patrick Weber
- Institut PasteurPlate‐forme de cristallographie‐C2RTUMR‐3528 CNRSParis75015France
| | - Ariel Mechaly
- Institut PasteurPlate‐forme de cristallographie‐C2RTUMR‐3528 CNRSParis75015France
| | - Ahmed Haouz
- Institut PasteurPlate‐forme de cristallographie‐C2RTUMR‐3528 CNRSParis75015France
| | - Nicolas Rodriguez
- Sorbonne UniversitéÉcole normale supérieurePSL UniversityCNRSLaboratoire des biomoléculesLBMParis75005France
| | - Patrice Vachette
- Université Paris‐SaclayCEACNRSInstitute for Integrative Biology of the Cell (I2BC)Gif‐sur‐Yvette91198France
| | - Dominique Durand
- Université Paris‐SaclayCEACNRSInstitute for Integrative Biology of the Cell (I2BC)Gif‐sur‐Yvette91198France
| | - Sébastien Brier
- Biological NMR Technological PlateformCenter for Technological Resources and ResearchDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Daniel Ladant
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
| | - Alexandre Chenal
- Biochemistry of Macromolecular Interactions UnitDepartment of Structural Biology and ChemistryInstitut PasteurCNRS UMR3528Paris75015France
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15
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Protein intrinsic viscosity determination with the Viscosizer TD instrument: reaching beyond the initially expected applications. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:587-595. [PMID: 33486532 DOI: 10.1007/s00249-020-01492-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 12/03/2020] [Accepted: 12/20/2020] [Indexed: 10/22/2022]
Abstract
Intrinsic viscosity is a key hydrodynamic parameter to understand molecular structure and hydration, as well as intramolecular interactions. Commercially available instruments measure intrinsic viscosity by recording the macromolecular mobility in a capillary. These instruments monitor Taylor dispersion using an absorbance or fluorescence detector. By design, these instruments behave like U-tube viscometers. To our knowledge, there are no studies to date showing that the Viscosizer TD instrument (Malvern-Panalytical) is able to measure the intrinsic viscosity of macromolecules. In this study, we then performed our assays on the Poly(ethylene oxide) polymer (PEO), used classically as a standard for viscometry measurements and on three model proteins: the bovine serum albumin (BSA), the bevacizumab monoclonal antibody, and the RTX Repeat Domain (RD) of the adenylate cyclase toxin of Bordetella pertussis (CyaA). The presence of P20 in the samples is critical to get reliable results. The data obtained with our in-house protocol show a strong correlation with intrinsic viscosity values obtained using conventional techniques. However, with respect to them, our measurements could be performed at relatively low concentrations, between 2 and 5 mg/ml, using only 7 µL per injection. Altogether, our results show that the Viscosizer TD instrument is able to measure intrinsic viscosities in a straightforward manner. This simple and innovative approach should give a new boost to intrinsic viscosity measurements and should reignite the interest of biophysicists, immunologists, structural biologists and other researchers for this key physicochemical parameter.
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16
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Secrete or perish: The role of secretion systems in Xanthomonas biology. Comput Struct Biotechnol J 2020; 19:279-302. [PMID: 33425257 PMCID: PMC7777525 DOI: 10.1016/j.csbj.2020.12.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Xanthomonas genus are mainly phytopathogens of a large variety of crops of economic importance worldwide. Xanthomonas spp. rely on an arsenal of protein effectors, toxins and adhesins to adapt to the environment, compete with other microorganisms and colonize plant hosts, often causing disease. These protein effectors are mainly delivered to their targets by the action of bacterial secretion systems, dedicated multiprotein complexes that translocate proteins to the extracellular environment or directly into eukaryotic and prokaryotic cells. Type I to type VI secretion systems have been identified in Xanthomonas genomes. Recent studies have unravelled the diverse roles played by the distinct types of secretion systems in adaptation and virulence in xanthomonads, unveiling new aspects of their biology. In addition, genome sequence information from a wide range of Xanthomonas species and pathovars have become available recently, uncovering a heterogeneous distribution of the distinct families of secretion systems within the genus. In this review, we describe the architecture and mode of action of bacterial type I to type VI secretion systems and the distribution and functions associated with these important nanoweapons within the Xanthomonas genus.
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Ali NSM, Salleh AB, Leow TC, Rahman RNZRA, Ali MSM. The Influence of Calcium toward Order/Disorder Conformation of Repeat-in-Toxin (RTX) Structure of Family I.3 Lipase from Pseudomonas fluorescens AMS8. Toxins (Basel) 2020; 12:toxins12090579. [PMID: 32916891 PMCID: PMC7551394 DOI: 10.3390/toxins12090579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
Calcium-binding plays a decisive role in the folding and stabilization of many RTX proteins, especially for the RTX domain. Although many studies have been conducted to prove the contribution of Ca2+ ion toward the folding and stabilization of RTX proteins, its functional dynamics and conformational structural changes remain elusive. Here, molecular docking and molecular dynamics (MD) simulations were performed to analyze the contribution of Ca2+ ion toward the folding and stabilization of the RTX lipase (AMS8 lipase) structure. AMS8 lipase contains six Ca2+ ions (Ca1–Ca6). Three Ca2+ ions (Ca3, Ca4, and Ca5) were bound to the RTX parallel β-roll motif repeat structure (RTX domain). The metal ion (Ca2+) docking analysis gives a high binding energy, especially for Ca4 and Ca5 which are tightly bound to the RTX domain. The function of each Ca2+ ion is further analyzed using the MD simulation. The removal of Ca3, Ca4, and Ca5 caused the AMS8 lipase structure to become unstable and unfolded. The results suggested that Ca3, Ca4, and Ca5 stabilized the RTX domain. In conclusion, Ca3, Ca4, and Ca5 play a crucial role in the folding and stabilization of the RTX domain, which sustain the integrity of the overall AMS8 lipase structure.
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Affiliation(s)
- Nur Shidaa Mohd Ali
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Abu Bakar Salleh
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
| | - Thean Chor Leow
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Raja Noor Zaliha Raja Abd Rahman
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia; (N.S.M.A.); (A.B.S.); (T.C.L.); (R.N.Z.R.A.R.)
- Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
- Correspondence:
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18
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Motlova L, Klimova N, Fiser R, Sebo P, Bumba L. Continuous Assembly of β-Roll Structures Is Implicated in the Type I-Dependent Secretion of Large Repeat-in-Toxins (RTX) Proteins. J Mol Biol 2020; 432:5696-5710. [PMID: 32860773 DOI: 10.1016/j.jmb.2020.08.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 01/10/2023]
Abstract
Repeats-in-Toxin (RTX) proteins of Gram-negative bacteria are excreted through the type I secretion system (T1SS) that recognizes non-cleavable C-terminal secretion signals. These are preceded by arrays of glycine and aspartate-rich nonapeptide repeats grouped by four to eight β strands into blocks that fold into calcium-binding parallel β-roll structures. The β-rolls are interspersed by linkers of variable length and sequence and the organization of multiple RTX repeat blocks within large RTX domains remains unknown. Here we examined the structure and function of the RTX domain of Bordetella pertussis adenylate cyclase toxin (CyaA) that is composed of five β-roll RTX blocks. We show that the non-folded RTX repeats maintain the stability of the CyaA polypeptide in the Ca2+-depleted bacterial cytosol and thereby enable its efficient translocation through the T1SS apparatus. The efficacy of secretion of truncated CyaA constructs was dictated by the number of retained RTX repeat blocks and depended on the presence of extracellular Ca2+ ions. We further describe the crystal structure of the RTX blocks IV-V of CyaA (CyaA1372-1681) that consists of a contiguous assembly of two β-rolls that differs substantially from the arrangement of the RTX blocks observed in RTX lipases or other RTX proteins. These results provide a novel structural insight into the architecture of the RTX domains of large RTX proteins and support the "push-ratchet" mechanism of the T1SS-mediated secretion of very large RTX proteins.
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Affiliation(s)
- Lucia Motlova
- Faculty of Sciences, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Nela Klimova
- Faculty of Sciences, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic.; Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Radovan Fiser
- Faculty of Sciences, Charles University, Vinicna 5, 128 44 Prague 2, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic..
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19
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Collins AJ, Smith TJ, Sondermann H, O'Toole GA. From Input to Output: The Lap/c-di-GMP Biofilm Regulatory Circuit. Annu Rev Microbiol 2020; 74:607-631. [PMID: 32689917 DOI: 10.1146/annurev-micro-011520-094214] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Biofilms are the dominant bacterial lifestyle. The regulation of the formation and dispersal of bacterial biofilms has been the subject of study in many organisms. Over the last two decades, the mechanisms of Pseudomonas fluorescens biofilm formation and regulation have emerged as among the best understood of any bacterial biofilm system. Biofilm formation by P. fluorescens occurs through the localization of an adhesin, LapA, to the outer membrane via a variant of the classical type I secretion system. The decision between biofilm formation and dispersal is mediated by LapD, a c-di-GMP receptor, and LapG, a periplasmic protease, which together control whether LapA is retained or released from the cell surface. LapA localization is also controlled by a complex network of c-di-GMP-metabolizing enzymes. This review describes the current understanding of LapA-mediated biofilm formation by P. fluorescens and discusses several emerging models for the regulation and function of this adhesin.
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Affiliation(s)
- Alan J Collins
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.,Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA;
| | - T Jarrod Smith
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA; .,Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
| | | | - George A O'Toole
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA;
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20
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Bugge K, Brakti I, Fernandes CB, Dreier JE, Lundsgaard JE, Olsen JG, Skriver K, Kragelund BB. Interactions by Disorder - A Matter of Context. Front Mol Biosci 2020; 7:110. [PMID: 32613009 PMCID: PMC7308724 DOI: 10.3389/fmolb.2020.00110] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/11/2020] [Indexed: 12/15/2022] Open
Abstract
Living organisms depend on timely and organized interactions between proteins linked in interactomes of high complexity. The recent increased precision by which protein interactions can be studied, and the enclosure of intrinsic structural disorder, suggest that it is time to zoom out and embrace protein interactions beyond the most central points of physical encounter. The present paper discusses protein-protein interactions in the view of structural disorder with an emphasis on flanking regions and contexts of disorder-based interactions. Context constitutes an overarching concept being of physicochemical, biomolecular, and physiological nature, but it also includes the immediate molecular context of the interaction. For intrinsically disordered proteins, which often function by exploiting short linear motifs, context contributes in highly regulatory and decisive manners and constitute a yet largely unrecognized source of interaction potential in a multitude of biological processes. Through selected examples, this review emphasizes how multivalency, charges and charge clusters, hydrophobic patches, dynamics, energetic frustration, and ensemble redistribution of flanking regions or disordered contexts are emerging as important contributors to allosteric regulation, positive and negative cooperativity, feedback regulation and negative selection in binding. The review emphasizes that understanding context, and in particular the role the molecular disordered context and flanking regions take on in protein interactions, constitute an untapped well of energetic modulation potential, also of relevance to drug discovery and development.
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Affiliation(s)
- Katrine Bugge
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Inna Brakti
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Catarina B. Fernandes
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jesper E. Dreier
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jeppe E. Lundsgaard
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Johan G. Olsen
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Karen Skriver
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Birthe B. Kragelund
- REPIN, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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21
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Krueger E, Brown AC. Aggregatibacter actinomycetemcomitans leukotoxin: From mechanism to targeted anti-toxin therapeutics. Mol Oral Microbiol 2020; 35:85-105. [PMID: 32061022 PMCID: PMC7359886 DOI: 10.1111/omi.12284] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/13/2022]
Abstract
Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium associated with localized aggressive periodontitis, as well as other systemic diseases. This organism produces a number of virulence factors, all of which provide some advantage to the bacterium. Several studies have demonstrated that clinical isolates from diseased patients, particularly those of African descent, frequently belong to specific clones of A. actinomycetemcomitans that produce significantly higher amounts of a protein exotoxin belonging to the repeats-in-toxin (RTX) family, leukotoxin (LtxA), whereas isolates from healthy patients harbor minimally leukotoxic strains. This finding suggests that LtxA might play a key role in A. actinomycetemcomitans pathogenicity. Because of this correlation, much work over the past 30 years has been focused on understanding the mechanisms by which LtxA interacts with and kills host cells. In this article, we review those findings, highlight the remaining open questions, and demonstrate how knowledge of these mechanisms, particularly the toxin's interactions with lymphocyte function-associated antigen-1 (LFA-1) and cholesterol, enables the design of targeted anti-LtxA strategies to prevent/treat disease.
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Affiliation(s)
- Eric Krueger
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Angela C. Brown
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
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22
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Calcium-Induced Activity and Folding of a Repeat in Toxin Lipase from Antarctic Pseudomonas fluorescens Strain AMS8. Toxins (Basel) 2020; 12:toxins12010027. [PMID: 31906409 PMCID: PMC7020413 DOI: 10.3390/toxins12010027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/25/2019] [Accepted: 10/30/2019] [Indexed: 11/23/2022] Open
Abstract
It is hypothesized that the Ca2+ ions were involved in the activity, folding and stabilization of many protein structures. Many of these proteins contain repeat in toxin (RTX) motifs. AMS8 lipase from Antarctic Pseudomonas fluorescens strain AMS8 was found to have three RTX motifs. So, this research aimed to examine the influence of Ca2+ ion towards the activity and folding of AMS8 lipase through various biophysical characterizations. The results showed that CaCl2 increased lipase activity. The far-UV circular dichroism (CD) and Fourier-transform infrared (FTIR) analysis suggested that the secondary structure content was improved with the addition of CaCl2. Fluorescence spectroscopy analysis showed that the presence of CaCl2 increased protein folding and compactness. Dynamic light scattering (DLS) analysis suggested that AMS8 lipase became aggregated at a high concentration of CaCl2.The binding constant (Kd) value from the isothermal titration calorimetry (ITC) analysis proved that the Ca2+ ion was tightly bound to the AMS8 lipase. In conclusion, Ca2+ ions play crucial roles in the activity and folding of the AMS8 lipase. Calcium binding to RTX nonapeptide repeats sequences will induced the formation and folding of the RTX parallel β-roll motif repeat structure.
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23
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A bacterial surface layer protein exploits multistep crystallization for rapid self-assembly. Proc Natl Acad Sci U S A 2019; 117:388-394. [PMID: 31848245 PMCID: PMC6955313 DOI: 10.1073/pnas.1909798116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Many microbes assemble a crystalline protein layer on their outer surface as an additional barrier and communication platform between the cell and its environment. Surface layer proteins efficiently crystallize to continuously coat the cell, and this trait has been utilized to design functional macromolecular nanomaterials. Here, we report that rapid crystallization of a bacterial surface layer protein occurs through a multistep pathway involving a crystalline intermediate. Upon calcium binding, sequential changes occur in the structure and arrangement of the protein, which are captured by time-resolved small angle X-ray scattering and transmission electron cryo-microscopy. We demonstrate that a specific domain is responsible for enhancing the rate of self-assembly, unveiling possible evolutionary mechanisms to enhance the kinetics of 2D protein crystallization. Surface layers (S-layers) are crystalline protein coats surrounding microbial cells. S-layer proteins (SLPs) regulate their extracellular self-assembly by crystallizing when exposed to an environmental trigger. However, molecular mechanisms governing rapid protein crystallization in vivo or in vitro are largely unknown. Here, we demonstrate that the Caulobacter crescentus SLP readily crystallizes into sheets in vitro via a calcium-triggered multistep assembly pathway. This pathway involves 2 domains serving distinct functions in assembly. The C-terminal crystallization domain forms the physiological 2-dimensional (2D) crystal lattice, but full-length protein crystallizes multiple orders of magnitude faster due to the N-terminal nucleation domain. Observing crystallization using a time course of electron cryo-microscopy (Cryo-EM) imaging reveals a crystalline intermediate wherein N-terminal nucleation domains exhibit motional dynamics with respect to rigid lattice-forming crystallization domains. Dynamic flexibility between the 2 domains rationalizes efficient S-layer crystal nucleation on the curved cellular surface. Rate enhancement of protein crystallization by a discrete nucleation domain may enable engineering of kinetically controllable self-assembling 2D macromolecular nanomaterials.
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24
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Wang H, Gao X, Li H. Single Molecule Force Spectroscopy Reveals the Mechanical Design Governing the Efficient Translocation of the Bacterial Toxin Protein RTX. J Am Chem Soc 2019; 141:20498-20506. [DOI: 10.1021/jacs.9b11281] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Han Wang
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Xiaoqing Gao
- State Key Laboratory of Precision Measuring Technology and Instruments School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin, 300072, P. R. China
| | - Hongbin Li
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
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25
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Baumann U. Structure-Function Relationships of the Repeat Domains of RTX Toxins. Toxins (Basel) 2019; 11:toxins11110657. [PMID: 31718085 PMCID: PMC6891781 DOI: 10.3390/toxins11110657] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 01/08/2023] Open
Abstract
RTX proteins are a large family of polypeptides of mainly Gram-negative origin that are secreted into the extracellular medium by a type I secretion system featuring a non-cleavable C-terminal secretion signal, which is preceded by a variable number of nine-residue tandem repeats. The three-dimensional structure forms a parallel β-roll, where β-strands of two parallel sheets are connected by calcium-binding linkers in such a way that a right-handed spiral is built. The Ca2+ ions are an integral part of the structure, which cannot form without them. The structural determinants of this unique architecture will be reviewed with its conservations and variations together with the implication for secretion and folding of these proteins. The general purpose of the RTX domains appears to act as an internal chaperone that keeps the polypeptide unfolded in the calcium-deprived cytosol and triggers folding in the calcium-rich extracellular medium. A rather recent addition to the structural biology of the RTX toxin is a variant occurring in a large RTX adhesin, where this non-canonical β-roll binds to ice and diatoms.
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Affiliation(s)
- Ulrich Baumann
- Institute of Biochemistry, University of Cologne, Zülpicherstrasse 47, D-50674 Cologne, Germany
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26
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O'Brien DP, Cannella SE, Voegele A, Raoux-Barbot D, Davi M, Douché T, Matondo M, Brier S, Ladant D, Chenal A. Post-translational acylation controls the folding and functions of the CyaA RTX toxin. FASEB J 2019; 33:10065-10076. [PMID: 31226003 DOI: 10.1096/fj.201802442rr] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The adenylate cyclase (CyaA) toxin is a major virulence factor of Bordetella pertussis, the causative agent of whooping cough. CyaA is synthetized as a pro-toxin, pro-CyaA, and converted into its cytotoxic form upon acylation of two lysines. After secretion, CyaA invades eukaryotic cells and produces cAMP, leading to host defense subversion. To gain further insights into the effect of acylation, we compared the functional and structural properties of pro-CyaA and CyaA proteins. HDX-MS results show that the refolding process of both proteins upon progressive urea removal is initiated by calcium binding to the C-terminal RTX domain. We further identified a critical hydrophobic segment, distal from the acylation region, that folds at higher urea concentration in CyaA than in pro-CyaA. Once refolded into monomers, CyaA is more compact and stable than pro-CyaA, due to a complex set of interactions between domains. Our HDX-MS data provide direct evidence that the presence of acyl chains in CyaA induces a significant stabilization of the apolar segments of the hydrophobic domain and of most of the acylation region. We propose a refolding model dependent on calcium and driven by local and distal acylation-dependent interactions within CyaA. Therefore, CyaA acylation is not only critical for cell intoxication, but also for protein refolding into its active conformation. Our data shed light on the complex relationship between post-translational modifications, structural disorder and protein folding. Coupling calcium-binding and acylation-driven folding is likely pertinent for other repeat-in-toxin cytolysins produced by many Gram-negative bacterial pathogens.-O'Brien, D. P., Cannella, S. E., Voegele, A., Raoux-Barbot, D., Davi, M., Douché, T., Matondo, M., Brier, S., Ladant, D., Chenal, A. Post-translational acylation controls the folding and functions of the CyaA RTX toxin.
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Affiliation(s)
- Darragh P O'Brien
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Sara E Cannella
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Alexis Voegele
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France.,Université Paris Diderot Paris VII, Sorbonne Paris Cité, Paris, France
| | - Dorothée Raoux-Barbot
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Marilyne Davi
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Thibaut Douché
- Institut Pasteur, Proteomics Platform, Mass Spectrometry for Biology Unit, USR CNRS 2000, Paris, France
| | - Mariette Matondo
- Institut Pasteur, Proteomics Platform, Mass Spectrometry for Biology Unit, USR CNRS 2000, Paris, France
| | - Sébastien Brier
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France.,Biological NMR Technical Platform, Center for Technological Resources and Research, UMR CNRS 3528, Paris, France
| | - Daniel Ladant
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
| | - Alexandre Chenal
- Institut Pasteur, Chemistry and Structural Biology Department, UMR CNRS 3528, Paris, France
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27
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Ostolaza H, González-Bullón D, Uribe KB, Martín C, Amuategi J, Fernandez-Martínez X. Membrane Permeabilization by Pore-Forming RTX Toxins: What Kind of Lesions Do These Toxins Form? Toxins (Basel) 2019; 11:toxins11060354. [PMID: 31216745 PMCID: PMC6628442 DOI: 10.3390/toxins11060354] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 06/12/2019] [Accepted: 06/16/2019] [Indexed: 12/22/2022] Open
Abstract
Pore-forming toxins (PFTs) form nanoscale pores across target membranes causing cell death. The pore-forming cytolysins of the RTX (repeats in toxin) family belong to a steadily increasing family of proteins characterized by having in their primary sequences a number of glycine- and aspartate-rich nonapeptide repeats. They are secreted by a variety of Gram-negative bacteria and form ion-permeable pores in several cell types, such as immune cells, epithelial cells, or erythrocytes. Pore-formation by RTX-toxins leads to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. The pores formed in lipid bilayers by the RTX-toxins share some common properties such as cation selectivity and voltage-dependence. Hemolytic and cytolytic RTX-toxins are important virulence factors in the pathogenesis of the producing bacteria. And hence, understanding the function of these proteins at the molecular level is critical to elucidating their role in disease processes. In this review we summarize the current state of knowledge on pore-formation by RTX toxins, and include recent results from our own laboratory regarding the pore-forming activity of adenylate cyclase toxin (ACT or CyaA), a large protein toxin secreted by Bordetella pertussis, the bacterium causative of whooping cough.
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Affiliation(s)
- Helena Ostolaza
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - David González-Bullón
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Kepa B Uribe
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Cesar Martín
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Jone Amuategi
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
| | - Xabier Fernandez-Martínez
- Departamento de Bioquímica y Biología Molecular (UPV/EHU) and Instituto Biofisika (UPV/EHU, CSIC), Aptdo. 644, 48080 Bilbao, Spain.
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28
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Abstract
Type I secretion systems (T1SS) are widespread in Gram-negative bacteria, especially in pathogenic bacteria, and they secrete adhesins, iron-scavenger proteins, lipases, proteases, or pore-forming toxins in the unfolded state in one step across two membranes without any periplasmic intermediate into the extracellular space. The substrates of T1SS are in general characterized by a C-terminal secretion sequence and nonapeptide repeats, so-called GG repeats, located N terminal to the secretion sequence. These GG repeats bind Ca2+ ions in the extracellular space, which triggers folding of the entire protein. Here we summarize our current knowledge of how Gram-negative bacteria secrete these substrates, which can possess a molecular mass of up to 1,500 kDa. We also describe recent findings that demonstrate that the absence of periplasmic intermediates, the "classic" mode of action, does not hold true for all T1SS and that we are beginning to realize modifications of a common theme.
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29
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Walter J, Barra A, Doublet B, Céré N, Charon J, Michon T. Hydrodynamic Behavior of the Intrinsically Disordered Potyvirus Protein VPg, of the Translation Initiation Factor eIF4E and of their Binary Complex. Int J Mol Sci 2019; 20:E1794. [PMID: 30978975 PMCID: PMC6479716 DOI: 10.3390/ijms20071794] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 01/12/2023] Open
Abstract
Protein intrinsic disorder is involved in many biological processes and good experimental models are valuable to investigate its functions. The potyvirus genome-linked protein, VPg, displays many features of an intrinsically disordered protein. The virus cycle requires the formation of a complex between VPg and eIF4E, one of the host translation initiation factors. An in-depth characterization of the hydrodynamic properties of VPg, eIF4E, and of their binary complex VPg-eIF4E was carried out. Two complementary experimental approaches, size-exclusion chromatography and fluorescence anisotropy, which is more resolving and revealed especially suitable when protein concentration is the limiting factor, allowed to estimate monomers compaction upon complex formation. VPg possesses a high degree of hydration which is in agreement with its classification as a partially folded protein in between a molten and pre-molten globule. The natively disordered first 46 amino acids of eIF4E contribute to modulate the protein hydrodynamic properties. The addition of an N-ter His tag decreased the conformational entropy of this intrinsically disordered region. A comparative study between the two tagged and untagged proteins revealed the His tag contribution to proteins hydrodynamic behavior.
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Affiliation(s)
- Jocelyne Walter
- UMR 1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, CS 20032, 33140 Villenave d'Ornon, France.
| | - Amandine Barra
- UMR 1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, CS 20032, 33140 Villenave d'Ornon, France.
| | - Bénédicte Doublet
- UMR 1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, CS 20032, 33140 Villenave d'Ornon, France.
| | - Nicolas Céré
- UMR 1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, CS 20032, 33140 Villenave d'Ornon, France.
| | - Justine Charon
- UMR 1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, CS 20032, 33140 Villenave d'Ornon, France.
| | - Thierry Michon
- UMR 1332 Biologie du Fruit et Pathologie, INRA, Université de Bordeaux, CS 20032, 33140 Villenave d'Ornon, France.
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30
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Bulutoglu B, Banta S. Calcium-Dependent RTX Domains in the Development of Protein Hydrogels. Gels 2019; 5:E10. [PMID: 30823512 PMCID: PMC6473919 DOI: 10.3390/gels5010010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/20/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022] Open
Abstract
The RTX domains found in some pathogenic proteins encode repetitive peptide sequences that reversibly bind calcium and fold into the unique the β-roll secondary structure. Several of these domains have been studied in isolation, yielding key insights into their structure/function relationships. These domains are increasingly being used in protein engineering applications, where the calcium-induced control over structure can be exploited to gain new functions. Here we review recent advances in the use of RTX domains in the creation of calcium responsive biomaterials.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
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31
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Voegele A, Sadi M, Raoux-Barbot D, Douché T, Matondo M, Ladant D, Chenal A. The Adenylate Cyclase (CyaA) Toxin from Bordetella pertussis Has No Detectable Phospholipase A (PLA) Activity In Vitro. Toxins (Basel) 2019; 11:E111. [PMID: 30781809 PMCID: PMC6409671 DOI: 10.3390/toxins11020111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 02/11/2019] [Indexed: 12/11/2022] Open
Abstract
The adenylate cyclase (CyaA) toxin produced in Bordetella pertussis is the causative agent of whooping cough. CyaA exhibits the remarkable capacity to translocate its N-terminal adenyl cyclase domain (ACD) directly across the plasma membrane into the cytosol of eukaryotic cells. Once translocated, calmodulin binds and activates ACD, leading to a burst of cAMP that intoxicates the target cell. Previously, Gonzalez-Bullon et al. reported that CyaA exhibits a phospholipase A activity that could destabilize the membrane to facilitate ACD membrane translocation. However, Bumba and collaborators lately reported that they could not replicate these results. To clarify this controversy, we assayed the putative PLA activity of two CyaA samples purified in two different laboratories by using two distinct fluorescent probes reporting either PLA2 or both PLA1 and PLA2 activities, as well as in various experimental conditions (i.e., neutral or negatively charged membranes in different buffers.) However, we could not detect any PLA activity in these CyaA batches. Thus, our data independently confirm that CyaA does not possess any PLA activity.
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Affiliation(s)
- Alexis Voegele
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
- Université Paris Diderot Paris VII, 75013 Paris, France.
| | - Mirko Sadi
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
| | - Dorothée Raoux-Barbot
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
| | - Thibaut Douché
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS 2000, CEDEX 15, 75724 Paris, France.
| | - Mariette Matondo
- Mass Spectrometry for Biology Unit, Proteomics Platform, Institut Pasteur, USR CNRS 2000, CEDEX 15, 75724 Paris, France.
| | - Daniel Ladant
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
| | - Alexandre Chenal
- Chemistry and Structural Biology Department, Institut Pasteur, UMR CNRS 3528, CEDEX 15, 75724 Paris, France.
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32
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Gil C, Dorca-Arévalo J, Blasi J. Calcium enhances binding of Clostridium perfringens epsilon toxin to sulfatide. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1861:161-169. [PMID: 30463699 DOI: 10.1016/j.bbamem.2018.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 07/20/2018] [Accepted: 08/07/2018] [Indexed: 01/07/2023]
Abstract
Epsilon toxin (Etx) from Clostridium perfringens is synthesized as a very low-active prototoxin form (proEtx) that becomes active upon proteolytic activation and has the capacity to cross the blood-brain barrier (BBB), thereby producing severe neurological effects. The identity and requirements of host receptors of Etx remain a matter of controversy. In the present study, we analysed the binding of proEtx or Etx to liposomes containing distearoylphosphatidylcholine (DSPC), cholesterol and sulfatide, or alternatively to detergent-solubilized lipids, using surface plasmon resonance (SPR). We also tested the influence of calcium on Etx or proEtx binding. Our findings show that the presence of sulfatide in liposomes increases both Etx and proEtx binding, and Etx binding is enhanced by calcium. These results were corroborated when SPR was conducted with immobilized toxin, since detergent-solubilized sulfatide increases its binding to Etx in the presence of calcium, but not to proEtx. Moreover, binding affinity is also affected, since the treatment of liposomes with sulfatase causes the dissociation rate constants (KD) in both proEtx and Etx to increase, especially in the case of proEtx in the presence of calcium. In addition, protein-lipid overlay assays corroborated the calcium-induced enhancement of Etx binding to sulfatide, and to lipids extracted from sulfatide-enriched rat brain lipid rafts. In conclusion, the present work highlights the role of sulfatide as an important element in the pathophysiology of Etx and reveals the influence of calcium in the interaction of Etx, but not of proEtx, with the target membrane.
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Affiliation(s)
- C Gil
- Departament de Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, Bellaterra, Catalunya, Spain.
| | - J Dorca-Arévalo
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain; Institut de Neurociències, Universitat de Barcelona, Spain
| | - J Blasi
- Laboratory of Cellular and Molecular Neurobiology, Department of Pathology and Experimental Therapeutics, School of Medicine, University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Biomedical Research Institute of Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain; Institut de Neurociències, Universitat de Barcelona, Spain
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33
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Guttula D, Yao M, Baker K, Yang L, Goult BT, Doyle PS, Yan J. Calcium-mediated Protein Folding and Stabilization of Salmonella Biofilm-associated Protein A. J Mol Biol 2018; 431:433-443. [PMID: 30452884 DOI: 10.1016/j.jmb.2018.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/10/2018] [Accepted: 11/13/2018] [Indexed: 12/26/2022]
Abstract
Biofilm-associated proteins (BAPs) are important for early biofilm formation (adhesion) by bacteria and are also found in mature biofilms. BapA from Salmonella is a ~386-kDa surface protein, comprising 27 tandem repeats predicted to be bacterial Ig-like (BIg) domains. Such tandem repeats are conserved for BAPs across different bacterial species, but the function of these domains is not completely understood. In this work, we report the first study of the mechanical stability of the BapA protein. Using magnetic tweezers, we show that the folding of BapA BIg domains requires calcium binding and the folded domains have differential mechanical stabilities. Importantly, we identify that >100 nM concentration of calcium is needed for folding of the BIg domains, and the stability of the folded BIg domains is regulated by calcium over a wide concentration range from sub-micromolar (μM) to millimolar (mM). Only at mM calcium concentrations, as found in the extracellular environment, do the BIg domains have the saturated mechanical stability. BapA has been suggested to be involved in Salmonella invasion, and it is likely a crucial mechanical component of biofilms. Therefore, our results provide new insights into the potential roles of BapA as a structural maintenance component of Salmonella biofilm and also Salmonella invasion.
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Affiliation(s)
- Durgarao Guttula
- BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 138602, Republic of Singapore; Mechanobiology Institute (MBI), National University of Singapore (NUS), 117411, Republic of Singapore
| | - Mingxi Yao
- Mechanobiology Institute (MBI), National University of Singapore (NUS), 117411, Republic of Singapore
| | - Karen Baker
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Liang Yang
- School of Medicine, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Benjamin T Goult
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Patrick S Doyle
- BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 138602, Republic of Singapore; Department of Chemical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA.
| | - Jie Yan
- BioSystems and Micromechanics (BioSyM) IRG, Singapore-MIT Alliance for Research and Technology (SMART) Centre, 138602, Republic of Singapore; Mechanobiology Institute (MBI), National University of Singapore (NUS), 117411, Republic of Singapore; Department of Physics, National University of Singapore (NUS), 117542, Republic of Singapore.
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34
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Voegele A, O'Brien DP, Subrini O, Sapay N, Cannella SE, Enguéné VYN, Hessel A, Karst J, Hourdel V, Perez ACS, Davi M, Veneziano R, Chopineau J, Vachette P, Durand D, Brier S, Ladant D, Chenal A. Translocation and calmodulin-activation of the adenylate cyclase toxin (CyaA) of Bordetella pertussis. Pathog Dis 2018; 76:5188676. [PMID: 30452651 DOI: 10.1093/femspd/fty085] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/16/2018] [Indexed: 01/19/2023] Open
Abstract
The adenylate cyclase toxin (CyaA) is a multi-domain protein secreted by Bordetella pertussis, the causative agent of whooping cough. CyaA is involved in the early stages of respiratory tract colonization by Bordetella pertussis. CyaA is produced and acylated in the bacteria, and secreted via a dedicated secretion system. The cell intoxication process involves a unique mechanism of transport of the CyaA toxin catalytic domain (ACD) across the plasma membrane of eukaryotic cells. Once translocated, ACD binds to and is activated by calmodulin and produces high amounts of cAMP, subverting the physiology of eukaryotic cells. Here, we review our work on the identification and characterization of a critical region of CyaA, the translocation region, required to deliver ACD into the cytosol of target cells. The translocation region contains a segment that exhibits membrane-active properties, i.e. is able to fold upon membrane interaction and permeabilize lipid bilayers. We proposed that this region is required to locally destabilize the membrane, decreasing the energy required for ACD translocation. To further study the translocation process, we developed a tethered bilayer lipid membrane (tBLM) design that recapitulate the ACD transport across a membrane separating two hermetic compartments. We showed that ACD translocation is critically dependent on calcium, membrane potential, CyaA acylation and on the presence of calmodulin in the trans compartment. Finally, we describe how calmodulin-binding triggers key conformational changes in ACD, leading to its activation and production of supraphysiological concentrations of cAMP.
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Affiliation(s)
- Alexis Voegele
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France.,Université Paris Diderot Paris VII, 75013 Paris, France
| | - Darragh P O'Brien
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France.,University of Oxford, United Kingdom
| | - Orso Subrini
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Nicolas Sapay
- Bioaster Technology Research Institute, 69007 Lyon, France
| | - Sara E Cannella
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France.,University of Oxford, United Kingdom
| | - Véronique Yvette Ntsogo Enguéné
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Audrey Hessel
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Johanna Karst
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Véronique Hourdel
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Ana Cristina Sotomayor Perez
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Marilyne Davi
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Rémi Veneziano
- ICGM, UMR 5253 Univ Montpellier, CNRS, ENSCM, Montpellier 34095, France.,Department of Bioengineering, Volgenau School of Engineering, George Mason University, Fairfax, VA 22030-4422, USA
| | - Joel Chopineau
- ICGM, UMR 5253 Univ Montpellier, CNRS, ENSCM, Montpellier 34095, France
| | - Patrice Vachette
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette cedex 91198, France
| | - Dominique Durand
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette cedex 91198, France
| | - Sébastien Brier
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Daniel Ladant
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
| | - Alexandre Chenal
- Département de Biologie Structurale et Chimie, Institut Pasteur, CNRS UMR 3528, 28 Rue du Dr Roux, 75724 Paris, CEDEX 15, France
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35
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Brown AC, Boesze-Battaglia K, Balashova NV, Mas Gómez N, Speicher K, Tang HY, Duszyk ME, Lally ET. Membrane localization of the Repeats-in-Toxin (RTX) Leukotoxin (LtxA) produced by Aggregatibacter actinomycetemcomitans. PLoS One 2018; 13:e0205871. [PMID: 30335797 PMCID: PMC6193665 DOI: 10.1371/journal.pone.0205871] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/02/2018] [Indexed: 12/31/2022] Open
Abstract
The oral bacterium, Aggregatibacter actinomycetemcomitans, which is associated with localized aggressive periodontitis, as well as systemic infections including endocarditis, produces numerous virulence factors, including a repeats-in-toxin (RTX) protein called leukotoxin (LtxA), which kills human immune cells. The strains of A. actinomycetemcomitans most closely associated with disease have been shown to produce the most LtxA, suggesting that LtxA plays a significant role in the virulence of this organism. LtxA, like many of the RTX toxins, can be divided into four functional domains: an N-terminal hydrophobic domain, which contains a significant fraction of hydrophobic residues and has been proposed to play a role in the membrane interaction of the toxin; the central domain, which contains two lysine residues that are the sites of post-translational acylation; the repeat domain that is characteristic of the RTX toxins, and a C-terminal domain thought to be involved in secretion. In its initial interaction with the host cell, LtxA must bind to both cholesterol and an integrin receptor, lymphocyte function-associated antigen-1 (LFA-1). While both interactions are essential for toxicity, the domains of LtxA involved remain unknown. We therefore undertook a series of experiments, including tryptophan quenching and trypsin digestion, to characterize the structure of LtxA upon interaction with membranes of various lipid compositions. Our results demonstrate that LtxA adopts a U-shaped conformation in the membrane, with the N- and C-terminal domains residing outside of the membrane.
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Affiliation(s)
- Angela C. Brown
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Kathleen Boesze-Battaglia
- Department of Biochemistry, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Nataliya V. Balashova
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Nestor Mas Gómez
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Kaye Speicher
- Wistar Institute, Philadelphia, PA, United States of America
| | - Hsin-Yao Tang
- Wistar Institute, Philadelphia, PA, United States of America
| | - Margaret E. Duszyk
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
| | - Edward T. Lally
- Department of Pathology, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, United States of America
- * E-mail:
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Type 1 Does the Two-Step: Type 1 Secretion Substrates with a Functional Periplasmic Intermediate. J Bacteriol 2018; 200:JB.00168-18. [PMID: 29866808 DOI: 10.1128/jb.00168-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Bacteria have evolved several secretion strategies for polling and responding to environmental flux and insult. Of these, the type 1 secretion system (T1SS) is known to secrete an array of biologically diverse proteins-from small, <10-kDa bacteriocins to gigantic adhesins with a mass >1 MDa. For the last several decades, T1SSs have been characterized as a one-step translocation strategy whereby the secreted substrate is transported directly into the extracellular environment from the cytoplasm with no periplasmic intermediate. Recent phylogenetic, biochemical, and genetic evidences point to a distinct subgroup of T1SS machinery linked with a bacterial transglutaminase-like cysteine proteinase (BTLCP), which uses a two-step secretion mechanism. BTLCP-linked T1SSs transport a class of repeats-in-toxin (RTX) adhesins that are critical for biofilm formation. The prototype of this RTX adhesin group, LapA of Pseudomonas fluorescens Pf0-1, uses a novel N-terminal retention module to anchor the adhesin at the cell surface as a secretion intermediate threaded through the outer membrane-localized TolC-like protein LapE. This secretion intermediate is posttranslationally cleaved by the BTLCP family LapG protein to release LapA from its cognate T1SS pore. Thus, the secretion of LapA and related RTX adhesins into the extracellular environment appears to be a T1SS-mediated two-step process that involves a periplasmic intermediate. In this review, we contrast the T1SS machinery and substrates of the BLTCP-linked two-step secretion process with those of the classical one-step T1SS to better understand the newly recognized and expanded role of this secretion machinery.
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Chenal A, Ladant D. Bioengineering of Bordetella pertussis Adenylate Cyclase Toxin for Antigen-Delivery and Immunotherapy. Toxins (Basel) 2018; 10:E302. [PMID: 30037010 PMCID: PMC6070788 DOI: 10.3390/toxins10070302] [Citation(s) in RCA: 12] [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: 07/06/2018] [Revised: 07/16/2018] [Accepted: 07/18/2018] [Indexed: 11/16/2022] Open
Abstract
The adenylate cyclase toxin (CyaA) is one of the major virulence factors of Bordetella pertussis, the causative agent of whooping cough. CyaA is able to invade eukaryotic cells where, upon activation by endogenous calmodulin, it synthesizes massive amounts of cAMP that alters cellular physiology. The CyaA toxin is a 1706 residues-long bifunctional protein: the catalytic domain is located in the 400 amino-proximal residues, whereas the carboxy-terminal 1306 residues are implicated in toxin binding to the cellular receptor, the αMβ₂ (CD11b/CD18) integrin, and subsequently in the translocation of the catalytic domain across the cytoplasmic membrane of the target cells. Indeed, this protein is endowed with the unique capability of delivering its N-terminal catalytic domain directly across the plasma membrane of eukaryotic target cells. These properties have been exploited to engineer the CyaA toxin as a potent non-replicating vector able to deliver antigens into antigen presenting cells and elicit specific cell-mediated immune responses. Antigens of interest can be inserted into the CyaA protein to yield recombinant molecules that are targeted in vivo to dendritic cells, where the antigens are processed and presented by the major class I and class II histocompatibility complexes (MHC-I and II). CyaA turned out to be a remarkably effective and versatile vaccine vector capable of inducing all the components of the immune response (T-CD4, T-CD8, and antibody). In this chapter, we summarize the basic knowledge on the adenylate cyclase toxin and then describe the application of CyaA in vaccinology, including some recent results of clinical trials of immunotherapy using a recombinant CyaA vaccine.
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Affiliation(s)
- Alexandre Chenal
- Institut Pasteur, Biochemistry of Macromolecular Interactions Unit, UMR CNRS 3528, Structural Biology and Chemistry Department, 28 rue du Docteur Roux, 75724 Paris CEDEX 15, France.
| | - Daniel Ladant
- Institut Pasteur, Biochemistry of Macromolecular Interactions Unit, UMR CNRS 3528, Structural Biology and Chemistry Department, 28 rue du Docteur Roux, 75724 Paris CEDEX 15, France.
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O'Brien DP, Perez ACS, Karst J, Cannella SE, Enguéné VYN, Hessel A, Raoux-Barbot D, Voegele A, Subrini O, Davi M, Guijarro JI, Raynal B, Baron B, England P, Hernandez B, Ghomi M, Hourdel V, Malosse C, Chamot-Rooke J, Vachette P, Durand D, Brier S, Ladant D, Chenal A. Calcium-dependent disorder-to-order transitions are central to the secretion and folding of the CyaA toxin of Bordetella pertussis, the causative agent of whooping cough. Toxicon 2018; 149:37-44. [DOI: 10.1016/j.toxicon.2018.01.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/20/2017] [Accepted: 01/10/2018] [Indexed: 02/07/2023]
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Kanonenberg K, Spitz O, Erenburg IN, Beer T, Schmitt L. Type I secretion system—it takes three and a substrate. FEMS Microbiol Lett 2018; 365:4966979. [DOI: 10.1093/femsle/fny094] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/09/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Kerstin Kanonenberg
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Olivia Spitz
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Isabelle N Erenburg
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Tobias Beer
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
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Liu L, Wang H, Han Y, Lv S, Chen J. Using single molecule force spectroscopy to facilitate a rational design of Ca2+-responsive β-roll peptide-based hydrogels. J Mater Chem B 2018; 6:5303-5312. [DOI: 10.1039/c8tb01511b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mechanical stability of Ca2+-responsive β-roll peptides (RTX) is largely responsible for the Ca2+-dependent mechanical properties of the RTX-based hydrogels.
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Affiliation(s)
- Lichao Liu
- State Key Laboratory of Organic–Inorganic Composite Materials
- Beijing University of Chemical Technology
- Beijing 100029
- China
| | - Han Wang
- Department of Chemistry
- The University of British Columbia
- Vancouver
- Canada
| | - Yueying Han
- State Key Laboratory of Organic–Inorganic Composite Materials
- Beijing University of Chemical Technology
- Beijing 100029
- China
| | - Shanshan Lv
- State Key Laboratory of Organic–Inorganic Composite Materials
- Beijing University of Chemical Technology
- Beijing 100029
- China
- Department of Chemistry
| | - Jianfeng Chen
- State Key Laboratory of Organic–Inorganic Composite Materials
- Beijing University of Chemical Technology
- Beijing 100029
- China
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Type I Protein Secretion-Deceptively Simple yet with a Wide Range of Mechanistic Variability across the Family. EcoSal Plus 2017; 7. [PMID: 28084193 DOI: 10.1128/ecosalplus.esp-0019-2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A very large type I polypeptide begins to reel out from a ribosome; minutes later, the still unidentifiable polypeptide, largely lacking secondary structure, is now in some cases a thousand or more residues longer. Synthesis of the final hundred C-terminal residues commences. This includes the identity code, the secretion signal within the last 50 amino acids, designed to dock with a waiting ATP binding cassette (ABC) transporter. What happens next is the subject of this review, with the main, but not the only focus on hemolysin HlyA, an RTX protein toxin secreted by the type I system. Transport substrates range from small peptides to giant proteins produced by many pathogens. These molecules, without detectable cellular chaperones, overcome enormous barriers, crossing two membranes before final folding on the cell surface, involving a unique autocatalytic process.Unfolded HlyA is extruded posttranslationally, C-terminal first. The transenvelope "tunnel" is formed by HlyB (ABC transporter), HlyD (membrane fusion protein) straddling the inner membrane and periplasm and TolC (outer membrane). We present a new evaluation of the C-terminal secretion code, and the structure function of HlyD and HlyB at the heart of this nanomachine. Surprisingly, key details of the secretion mechanism are remarkably variable in the many type I secretion system subtypes. These include alternative folding processes, an apparently distinctive secretion code for each type I subfamily, and alternative forms of the ABC transporter; most remarkably, the ABC protein probably transports peptides or polypeptides by quite different mechanisms. Finally, we suggest a putative structure for the Hly-translocon, HlyB, the multijointed HlyD, and the TolC exit.
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Structure-Function Relationships Underlying the Capacity of Bordetella Adenylate Cyclase Toxin to Disarm Host Phagocytes. Toxins (Basel) 2017; 9:toxins9100300. [PMID: 28946636 PMCID: PMC5666347 DOI: 10.3390/toxins9100300] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 01/18/2023] Open
Abstract
Bordetellae, pathogenic to mammals, produce an immunomodulatory adenylate cyclase toxin-hemolysin (CyaA, ACT or AC-Hly) that enables them to overcome the innate immune defense of the host. CyaA subverts host phagocytic cells by an orchestrated action of its functional domains, where an extremely catalytically active adenylyl cyclase enzyme is delivered into phagocyte cytosol by a pore-forming repeat-in-toxin (RTX) cytolysin moiety. By targeting sentinel cells expressing the complement receptor 3, known as the CD11b/CD18 (αMβ₂) integrin, CyaA compromises the bactericidal functions of host phagocytes and supports infection of host airways by Bordetellae. Here, we review the state of knowledge on structural and functional aspects of CyaA toxin action, placing particular emphasis on signaling mechanisms by which the toxin-produced 3',5'-cyclic adenosine monophosphate (cAMP) subverts the physiology of phagocytic cells.
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Bulutoglu B, Banta S. Block V RTX Domain of Adenylate Cyclase from Bordetella pertussis: A Conformationally Dynamic Scaffold for Protein Engineering Applications. Toxins (Basel) 2017; 9:E289. [PMID: 28926974 PMCID: PMC5618222 DOI: 10.3390/toxins9090289] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 09/12/2017] [Accepted: 09/12/2017] [Indexed: 01/27/2023] Open
Abstract
The isolated Block V repeats-in-toxin (RTX) peptide domain of adenylate cyclase (CyaA) from Bordetella pertussis reversibly folds into a β-roll secondary structure upon calcium binding. In this review, we discuss how the conformationally dynamic nature of the peptide is being engineered and employed as a switching mechanism to mediate different protein functions and protein-protein interactions. The peptide has been used as a scaffold for diverse applications including: a precipitation tag for bioseparations, a cross-linking domain for protein hydrogel formation and as an alternative scaffold for biomolecular recognition applications. Proteins and peptides such as the RTX domains that exhibit natural stimulus-responsive behavior are valuable building blocks for emerging synthetic biology applications.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 W 120th Street, New York, NY 10027, USA.
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Bulutoglu B, Dooley K, Szilvay G, Blenner M, Banta S. Catch and Release: Engineered Allosterically Regulated β-Roll Peptides Enable On/Off Biomolecular Recognition. ACS Synth Biol 2017; 6:1732-1741. [PMID: 28520402 DOI: 10.1021/acssynbio.7b00089] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alternative scaffolds for biomolecular recognition are being developed to overcome some of the limitations associated with immunoglobulin domains. The repeat-in-toxin (RTX) domain is a repeat protein sequence that reversibly adopts the β-roll secondary structure motif specifically upon calcium binding. This conformational change was exploited for controlled biomolecular recognition. Using ribosome display, an RTX peptide library was selected to identify binders to a model protein, lysozyme, exclusively in the folded state of the peptide. Several mutants were identified with low micromolar dissociation constants. After concatenation of the mutants, a 500-fold increase in the overall affinity for lysozyme was achieved leading to a peptide with an apparent dissociation constant of 65 nM. This mutant was immobilized for affinity chromatography experiments, and the on/off nature of the molecular recognition was demonstrated as the target is captured from a mixture in the presence of calcium and is released in the absence of calcium as the RTX peptides lose their β-roll structure. This work presents the design of a new stimulus-responsive scaffold that can be used for environmentally responsive specific molecular recognition and self-assembly.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Kevin Dooley
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Géza Szilvay
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Mark Blenner
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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45
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Structural and functional dissection reveals distinct roles of Ca2+-binding sites in the giant adhesin SiiE of Salmonella enterica. PLoS Pathog 2017; 13:e1006418. [PMID: 28558023 PMCID: PMC5466336 DOI: 10.1371/journal.ppat.1006418] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 06/09/2017] [Accepted: 05/18/2017] [Indexed: 11/20/2022] Open
Abstract
The giant non-fimbrial adhesin SiiE of Salmonella enterica mediates the first contact to the apical site of epithelial cells and enables subsequent invasion. SiiE is a 595 kDa protein composed of 53 repetitive bacterial immunoglobulin (BIg) domains and the only known substrate of the SPI4-encoded type 1 secretion system (T1SS). The crystal structure of BIg50-52 of SiiE revealed two distinct Ca2+-binding sites per BIg domain formed by conserved aspartate or glutamate residues. In a mutational analysis Ca2+-binding sites were disrupted by aspartate to serine exchange at various positions in the BIg domains of SiiE. Amounts of secreted SiiE diminish with a decreasing number of intact Ca2+-binding sites. BIg domains of SiiE contain distinct Ca2+-binding sites, with type I sites being similar to other T1SS-secreted proteins and type II sites newly identified in SiiE. We functionally and structurally dissected the roles of type I and type II Ca2+-binding sites in SiiE, as well as the importance of Ca2+-binding sites in various positions of SiiE. Type I Ca2+-binding sites were critical for efficient secretion of SiiE and a decreasing number of type I sites correlated with reduced secretion. Type II sites were less important for secretion, stability and surface expression of SiiE, however integrity of type II sites in the C-terminal portion was required for the function of SiiE in mediating adhesion and invasion. The interaction of Salmonella enterica with polarized epithelial cells depends on the function of SiiE, a 595 kDa adhesin containing 53 repeats of a bacterial immunoglobulin (BIg) domain. SiiE is secreted and surface-expressed by a cognate type I secretion system (T1SS). We found that BIg domains contain amino acid (aa) residues forming binding sites for Ca2+ ions. Two types of Ca2+-binding sites can be distinguished, termed type I and type II sites. We performed a structural and functional dissection of Ca2+-binding sites of SiiE. After mutation of aa residues forming type I and/or type II Ca2+-binding sites, we investigated the secretion, surface expression and function as adhesin for interaction with polarized epithelial cells of the SiiE variants. We found that Ca2+-binding sites are critical for supporting the secretion of SiiE. Integrity of type I sites in any position of SiiE is essential for efficient secretion and surface expression. In contrast integrity of type II sites is less important for secretion. However, loss of type II in the C-terminal, most distal portion of SiiE ablated SiiE-mediated adhesion, while loss of the type II sites in middle or N-terminal portions of SiiE had less or no effect on SiiE function. We propose a novel mechanism of Ca2+-dependent secretion and conformational fine tuning of SiiE as a large T1SS substrate with a central role in the interaction of S. enterica with host cells.
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46
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Albumin, in the Presence of Calcium, Elicits a Massive Increase in Extracellular Bordetella Adenylate Cyclase Toxin. Infect Immun 2017; 85:IAI.00198-17. [PMID: 28396321 DOI: 10.1128/iai.00198-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 04/02/2017] [Indexed: 12/14/2022] Open
Abstract
Pertussis (whooping cough), caused by Bordetella pertussis, is resurging in the United States and worldwide. Adenylate cyclase toxin (ACT) is a critical factor in establishing infection with B. pertussis and acts by specifically inhibiting the response of myeloid leukocytes to the pathogen. We report here that serum components, as discovered during growth in fetal bovine serum (FBS), elicit a robust increase in the amount of ACT, and ≥90% of this ACT is localized to the supernatant, unlike growth without FBS, in which ≥90% is associated with the bacterium. We have found that albumin, in the presence of physiological concentrations of calcium, acts specifically to enhance the amount of ACT and its localization to the supernatant. Respiratory secretions, which contain albumin, promote an increase in amount and localization of active ACT that is comparable to that elicited by serum and albumin. The response to albumin is not mediated through regulation of ACT at the transcriptional level or activation of the Bvg two-component system. As further illustration of the specificity of this phenomenon, serum collected from mice that lack albumin does not stimulate an increase in ACT. These data, demonstrating that albumin and calcium act synergistically in the host environment to increase production and release of ACT, strongly suggest that this phenomenon reflects a novel host-pathogen interaction that is central to infection with B. pertussis and other Bordetella species.
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Herrmann J, Jabbarpour F, Bargar PG, Nomellini JF, Li PN, Lane TJ, Weiss TM, Smit J, Shapiro L, Wakatsuki S. Environmental Calcium Controls Alternate Physical States of the Caulobacter Surface Layer. Biophys J 2017; 112:1841-1851. [PMID: 28494955 PMCID: PMC5425405 DOI: 10.1016/j.bpj.2017.04.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/28/2017] [Accepted: 04/06/2017] [Indexed: 11/23/2022] Open
Abstract
Surface layers (S-layers) are paracrystalline, proteinaceous structures found in most archaea and many bacteria. Often the outermost cell envelope component, S-layers serve diverse functions including aiding pathogenicity and protecting against predators. We report that the S-layer of Caulobacter crescentus exhibits calcium-mediated structural plasticity, switching irreversibly between an amorphous aggregate state and the crystalline state. This finding invalidates the common assumption that S-layers serve only as static wall-like structures. In vitro, the Caulobacter S-layer protein, RsaA, enters the aggregate state at physiological temperatures and low divalent calcium ion concentrations. At higher concentrations, calcium ions stabilize monomeric RsaA, which can then transition to the two-dimensional crystalline state. Caulobacter requires micromolar concentrations of calcium for normal growth and development. Without an S-layer, Caulobacter is even more sensitive to changes in environmental calcium concentration. Therefore, this structurally dynamic S-layer responds to environmental conditions as an ion sensor and protects Caulobacter from calcium deficiency stress, a unique mechanism of bacterial adaptation. These findings provide a biochemical and physiological basis for RsaA's calcium-binding behavior, which extends far beyond calcium's commonly accepted role in aiding S-layer biogenesis or oligomerization and demonstrates a connection to cellular fitness.
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Affiliation(s)
- Jonathan Herrmann
- Department of Structural Biology, Stanford University, Stanford, California; Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California.
| | - Fatemeh Jabbarpour
- Department of Structural Biology, Stanford University, Stanford, California
| | | | - John F Nomellini
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Po-Nan Li
- Department of Electrical Engineering, Stanford University, Stanford, California
| | - Thomas J Lane
- Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California
| | - Thomas M Weiss
- Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California
| | - John Smit
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Lucy Shapiro
- Department of Developmental Biology, Stanford University, Stanford, California.
| | - Soichi Wakatsuki
- Department of Structural Biology, Stanford University, Stanford, California; Bioscience Division, SLAC National Accelerator Laboratory, Menlo Park, California.
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Cannella SE, Ntsogo Enguéné VY, Davi M, Malosse C, Sotomayor Pérez AC, Chamot-Rooke J, Vachette P, Durand D, Ladant D, Chenal A. Stability, structural and functional properties of a monomeric, calcium-loaded adenylate cyclase toxin, CyaA, from Bordetella pertussis. Sci Rep 2017; 7:42065. [PMID: 28186111 PMCID: PMC5301233 DOI: 10.1038/srep42065] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 01/04/2017] [Indexed: 12/21/2022] Open
Abstract
Bordetella pertussis, the causative agent of whooping cough, secretes an adenylate cyclase toxin, CyaA, which invades eukaryotic cells and alters their physiology by cAMP overproduction. Calcium is an essential cofactor of CyaA, as it is the case for most members of the Repeat-in-ToXins (RTX) family. We show that the calcium-bound, monomeric form of CyaA, hCyaAm, conserves its permeabilization and haemolytic activities, even in a fully calcium-free environment. In contrast, hCyaAm requires sub-millimolar calcium in solution for cell invasion, indicating that free calcium in solution is involved in the CyaA toxin translocation process. We further report the first in solution structural characterization of hCyaAm, as deduced from SAXS, mass spectrometry and hydrodynamic studies. We show that hCyaAm adopts a compact and stable state that can transiently conserve its conformation even in a fully calcium-free environment. Our results therefore suggest that in hCyaAm, the C-terminal RTX-domain is stabilized in a high-affinity calcium-binding state by the N-terminal domains while, conversely, calcium binding to the C-terminal RTX-domain strongly stabilizes the N-terminal regions. Hence, the different regions of hCyaAm appear tightly connected, leading to stabilization effects between domains. The hysteretic behaviour of CyaA in response to calcium is likely shared by other RTX cytolysins.
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Affiliation(s)
- Sara E. Cannella
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Marilyne Davi
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Christian Malosse
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | | | - Julia Chamot-Rooke
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Patrice Vachette
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Daniel Ladant
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Alexandre Chenal
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
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49
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Lenders MHH, Beer T, Smits SHJ, Schmitt L. In vivo quantification of the secretion rates of the hemolysin A Type I secretion system. Sci Rep 2016; 6:33275. [PMID: 27616645 PMCID: PMC5018854 DOI: 10.1038/srep33275] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/24/2016] [Indexed: 01/08/2023] Open
Abstract
Type 1 secretion systems (T1SS) of Gram-negative bacteria secrete a broad range of substrates into the extracellular space. Common to all substrates is a C-terminal secretion sequence and nonapeptide repeats in the C-terminal part that bind Ca2+ in the extracellular space, to trigger protein folding. Like all T1SS, the hemolysin A (HlyA) T1SS of Escherichia coli consists of an ABC transporter, a membrane fusion protein and an outer membrane protein allowing the one step translocation of the substrate across both membranes. Here, we analyzed the secretion rate of the HlyA T1SS. Our results demonstrate that the rate is independent of substrate-size and operates at a speed of approximately 16 amino acids per transporter per second. We also demonstrate that the rate is independent of the extracellular Ca2+ concentration raising the question of the driving force of substrate secretion by T1SS in general.
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Affiliation(s)
- Michael H H Lenders
- Institute of Biochemistry, Heinrich-Heine-Universitaet, 40225 Duesseldorf, Germany
| | - Tobias Beer
- Institute of Biochemistry, Heinrich-Heine-Universitaet, 40225 Duesseldorf, Germany
| | - Sander H J Smits
- Institute of Biochemistry, Heinrich-Heine-Universitaet, 40225 Duesseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich-Heine-Universitaet, 40225 Duesseldorf, Germany
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Masin J, Osickova A, Sukova A, Fiser R, Halada P, Bumba L, Linhartova I, Osicka R, Sebo P. Negatively charged residues of the segment linking the enzyme and cytolysin moieties restrict the membrane-permeabilizing capacity of adenylate cyclase toxin. Sci Rep 2016; 6:29137. [PMID: 27581058 PMCID: PMC5007505 DOI: 10.1038/srep29137] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 06/15/2016] [Indexed: 11/10/2022] Open
Abstract
The whooping cough agent, Bordetella pertussis, secretes an adenylate cyclase toxin-hemolysin (CyaA) that plays a crucial role in host respiratory tract colonization. CyaA targets CR3-expressing cells and disrupts their bactericidal functions by delivering into their cytosol an adenylate cyclase enzyme that converts intracellular ATP to cAMP. In parallel, the hydrophobic domain of CyaA forms cation-selective pores that permeabilize cell membrane. The invasive AC and pore-forming domains of CyaA are linked by a segment that is unique in the RTX cytolysin family. We used mass spectrometry and circular dichroism to show that the linker segment forms α-helical structures that penetrate into lipid bilayer. Replacement of the positively charged arginine residues, proposed to be involved in target membrane destabilization by the linker segment, reduced the capacity of the toxin to translocate the AC domain across cell membrane. Substitutions of negatively charged residues then revealed that two clusters of negative charges within the linker segment control the size and the propensity of CyaA pore formation, thereby restricting the cell-permeabilizing capacity of CyaA. The ‘AC to Hly-linking segment’ thus appears to account for the smaller size and modest cell-permeabilizing capacity of CyaA pores, as compared to typical RTX hemolysins.
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Affiliation(s)
- Jiri Masin
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Adriana Osickova
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Anna Sukova
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Radovan Fiser
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic.,Faculty of Science, Charles University, Prague, Czech Republic
| | - Petr Halada
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Ladislav Bumba
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Irena Linhartova
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Radim Osicka
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
| | - Peter Sebo
- Institute of Microbiology of the CAS, v. v. i., Prague, Czech Republic
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