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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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Knapp O, Benz R. Membrane Activity and Channel Formation of the Adenylate Cyclase Toxin (CyaA) of Bordetella pertussis in Lipid Bilayer Membranes. Toxins (Basel) 2020; 12:toxins12030169. [PMID: 32164365 PMCID: PMC7150934 DOI: 10.3390/toxins12030169] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/20/2020] [Accepted: 02/22/2020] [Indexed: 12/14/2022] Open
Abstract
The Gram-negative bacterium Bordetella pertussis is the cause of whooping cough. One of its pathogenicity factors is the adenylate cyclase toxin (CyaA) secreted by a Type I export system. The 1706 amino acid long CyaA (177 kDa) belongs to the continuously increasing family of repeat in toxin (RTX) toxins because it contains in its C-terminal half a high number of nine-residue tandem repeats. The protein exhibits cytotoxic and hemolytic activities that target primarily myeloid phagocytic cells expressing the αMβ2 integrin receptor (CD11b/CD18). CyaA represents an exception among RTX cytolysins because the first 400 amino acids from its N-terminal end possess a calmodulin-activated adenylate cyclase (AC) activity. The entry of the AC into target cells is not dependent on the receptor-mediated endocytosis pathway and penetrates directly across the cytoplasmic membrane of a variety of epithelial and immune effector cells. The hemolytic activity of CyaA is rather low, which may have to do with its rather low induced permeability change of target cells and its low conductance in lipid bilayer membranes. CyaA forms highly cation-selective channels in lipid bilayers that show a strong dependence on aqueous pH. The pore-forming activity of CyaA but not its single channel conductance is highly dependent on Ca2+ concentration with a half saturation constant of about 2 to 4 mM.
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Affiliation(s)
- Oliver Knapp
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759 Bremen, Germany
- Correspondence: (O.K.); (R.B.)
| | - Roland Benz
- Rudolf-Virchow-Center, University of Würzburg, Versbacher Str. 9, 97078 Würzburg, Germany
- Correspondence: (O.K.); (R.B.)
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3
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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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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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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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Hepp C, Maier B. Bacterial Translocation Ratchets: Shared Physical Principles with Different Molecular Implementations: How bacterial secretion systems bias Brownian motion for efficient translocation of macromolecules. Bioessays 2017; 39. [PMID: 28895164 DOI: 10.1002/bies.201700099] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 08/02/2017] [Indexed: 12/20/2022]
Abstract
Secretion systems enable bacteria to import and secrete large macromolecules including DNA and proteins. While most components of these systems have been identified, the molecular mechanisms of macromolecular transport remain poorly understood. Recent findings suggest that various bacterial secretion systems make use of the translocation ratchet mechanism for transporting polymers across the cell envelope. Translocation ratchets are powered by chemical potential differences generated by concentration gradients of ions or molecules that are specific to the respective secretion systems. Bacteria employ these potential differences for biasing Brownian motion of the macromolecules within the conduits of the secretion systems. Candidates for this mechanism include DNA import by the type II secretion/type IV pilus system, DNA export by the type IV secretion system, and protein export by the type I secretion system. Here, we propose that these three secretion systems employ different molecular implementations of the translocation ratchet mechanism.
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Affiliation(s)
- Christof Hepp
- Department of Physics Universität zu Köln, Köln, Nordrhein-Westfalen, Germany
| | - Berenike Maier
- Department of Physics Universität zu Köln, Köln, Nordrhein-Westfalen, Germany
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8
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Bumba L, Masin J, Macek P, Wald T, Motlova L, Bibova I, Klimova N, Bednarova L, Veverka V, Kachala M, Svergun D, Barinka C, Sebo P. Calcium-Driven Folding of RTX Domain β-Rolls Ratchets Translocation of RTX Proteins through Type I Secretion Ducts. Mol Cell 2016; 62:47-62. [DOI: 10.1016/j.molcel.2016.03.018] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 12/31/2015] [Accepted: 03/15/2016] [Indexed: 11/17/2022]
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9
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Benz R. Channel formation by RTX-toxins of pathogenic bacteria: Basis of their biological activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:526-37. [PMID: 26523409 DOI: 10.1016/j.bbamem.2015.10.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/10/2015] [Accepted: 10/28/2015] [Indexed: 12/15/2022]
Abstract
The pore-forming cytolysins of the RTX-toxin (Repeats in ToXin) family are a relatively small fraction of a steadily increasing family of proteins that contain several functionally important glycine-rich and aspartate containing nonapeptide repeats. These cytolysins produced by a variety of Gram-negative bacteria form ion-permeable channels in erythrocytes and other eukaryotic cells. Hemolytic and cytolytic RTX-toxins represent pathogenicity factors of the toxin-producing bacteria and are very often important key factors in pathogenesis of the bacteria. Channel formation by RTX-toxins lead to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. Here we discuss channel formation and channel properties of some of the best known RTX-toxins, such as α-hemolysin (HlyA) of Escherichia coli and the uropathogenic EHEC strains, the adenylate cyclase toxin (ACT, CyaA) of Bordetella pertussis and the RTX-toxins (ApxI, ApxII and ApxIII) produced by different strains of Actinobacillus pleuropneumoniae. The channels formed by these RTX-toxins in lipid bilayers share some common properties such as cation selectivity and voltage-dependence. Furthermore the channels are transient and show frequent switching between different ion-conducting states. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759, Bremen, Germany.
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10
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O'Brien DP, Hernandez B, Durand D, Hourdel V, Sotomayor-Pérez AC, Vachette P, Ghomi M, Chamot-Rooke J, Ladant D, Brier S, Chenal A. Structural models of intrinsically disordered and calcium-bound folded states of a protein adapted for secretion. Sci Rep 2015; 5:14223. [PMID: 26374675 PMCID: PMC4642704 DOI: 10.1038/srep14223] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/20/2015] [Indexed: 01/28/2023] Open
Abstract
Many Gram-negative bacteria use Type I secretion systems, T1SS, to secrete virulence factors that contain calcium-binding Repeat-in-ToXin (RTX) motifs. Here, we present structural models of an RTX protein, RD, in both its intrinsically disordered calcium-free Apo-state and its folded calcium-bound Holo-state. Apo-RD behaves as a disordered polymer chain comprising several statistical elements that exhibit local rigidity with residual secondary structure. Holo-RD is a folded multi-domain protein with an anisometric shape. RTX motifs thus appear remarkably adapted to the structural and mechanistic constraints of the secretion process. In the low calcium environment of the bacterial cytosol, Apo-RD is an elongated disordered coil appropriately sized for transport through the narrow secretion machinery. The progressive folding of Holo-RD in the extracellular calcium-rich environment as it emerges form the T1SS may then favor its unidirectional export through the secretory channel. This process is relevant for hundreds of bacterial species producing virulent RTX proteins.
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Affiliation(s)
- Darragh P O'Brien
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Belen Hernandez
- Sorbonne Paris Cité, Université Paris 13, Groupe de Biophysique Moléculaire, UFR Santé-Médecine-Biologie Humaine, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France
| | - Dominique Durand
- Institut de Biologie Intégrative de la Cellule, UMR 9198, Université Paris-Sud, F-91405 ORSAY Cedex, France
| | - Véronique Hourdel
- 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
| | - Mahmoud Ghomi
- Sorbonne Paris Cité, Université Paris 13, Groupe de Biophysique Moléculaire, UFR Santé-Médecine-Biologie Humaine, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France
| | - Julia Chamot-Rooke
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Daniel Ladant
- Institut Pasteur, UMR CNRS 3528, Chemistry and Structural Biology Department, 75724 PARIS cedex 15, France
| | - Sébastien Brier
- 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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Pandit RA, Meetum K, Suvarnapunya K, Katzenmeier G, Chaicumpa W, Angsuthanasombat C. Isolated CyaA-RTX subdomain from Bordetella pertussis: Structural and functional implications for its interaction with target erythrocyte membranes. Biochem Biophys Res Commun 2015; 466:76-81. [PMID: 26325465 DOI: 10.1016/j.bbrc.2015.08.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 08/24/2015] [Indexed: 10/23/2022]
Abstract
The 126-kDa Bordetella pertussis CyaA-hemolysin (CyaA-Hly) was previously expressed in Escherichia coli as a soluble precursor that can be acylated to retain hemolytic activity. Here, we investigated structural and functional characteristics of a ∼100-kDa isolated RTX (Repeat-in-ToXin) subdomain (CyaA-RTX) of CyaA-Hly. Initially, we succeeded in producing a large amount with high purity of the His-tagged CyaA-RTX fragment and in establishing the interaction of acylated CyaA-Hly with sheep red blood cell (sRBC) membranes by immuno-localization. Following pre-incubation of sRBCs with non-acylated CyaA-Hly or with the CyaA-RTX fragment that itself produces no hemolytic activity, there was a dramatic decrease in CyaA-Hly-induced hemolysis. When CyaA-RTX was pre-incubated with anti-CyaA-RTX antisera, the capability of CyaA-RTX to neutralize the hemolytic activity of CyaA-Hly was greatly decreased. A homology-based model of the 100-kDa CyaA-RTX subdomain revealed a loop structure in Linker II sharing sequence similarity to human WW domains. Sequence alignment of Linker II with the human WW-domain family revealed highly conserved aromatic residues important for protein-protein interactions. Altogether, our present study demonstrates that the recombinant CyaA-RTX subdomain retains its functionality with respect to binding to target erythrocyte membranes and the WW-homologous region in Linker II conceivably serves as a functional segment required for receptor-binding activity.
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Affiliation(s)
- Riyaz Ahmad Pandit
- Graduate Program in Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Kanungsuk Meetum
- Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Kittipong Suvarnapunya
- Graduate Program in Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Gerd Katzenmeier
- Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand
| | - Wanpen Chaicumpa
- Department of Parasitology and Center of Excellence on Therapeutic Proteins and Antibody Engineering, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Chanan Angsuthanasombat
- Bacterial Protein Toxin Research Cluster, Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakornpathom 73170, Thailand; Laboratory of Molecular Biophysics and Structural Biochemistry, Biophysics Institute for Research and Development (BIRD), Bangkok 10160, Thailand.
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12
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Disorder-to-order transition in the CyaA toxin RTX domain: implications for toxin secretion. Toxins (Basel) 2014; 7:1-20. [PMID: 25559101 PMCID: PMC4303809 DOI: 10.3390/toxins7010001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 12/24/2014] [Indexed: 11/23/2022] Open
Abstract
The past decade has seen a fundamental reappraisal of the protein structure-to-function paradigm because it became evident that a significant fraction of polypeptides are lacking ordered structures under physiological conditions. Ligand-induced disorder-to-order transition plays a key role in the biological functions of many proteins that contain intrinsically disordered regions. This trait is exhibited by RTX (Repeat in ToXin) motifs found in more than 250 virulence factors secreted by Gram-negative pathogenic bacteria. We have investigated several RTX-containing polypeptides of different lengths, all derived from the Bordetella pertussis adenylate cyclase toxin, CyaA. Using a combination of experimental approaches, we showed that the RTX proteins exhibit the hallmarks of intrinsically disordered proteins in the absence of calcium. This intrinsic disorder mainly results from internal electrostatic repulsions between negatively charged residues of the RTX motifs. Calcium binding triggers a strong reduction of the mean net charge, dehydration and compaction, folding and stabilization of secondary and tertiary structures of the RTX proteins. We propose that the intrinsically disordered character of the RTX proteins may facilitate the uptake and secretion of virulence factors through the bacterial secretion machinery. These results support the hypothesis that the folding reaction is achieved upon protein secretion and, in the case of proteins containing RTX motifs, could be finely regulated by the calcium gradient across bacterial cell wall.
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Sebo P, Osicka R, Masin J. Adenylate cyclase toxin-hemolysin relevance for pertussis vaccines. Expert Rev Vaccines 2014; 13:1215-27. [PMID: 25090574 DOI: 10.1586/14760584.2014.944900] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The adenylate cyclase toxin-hemolysin (ACT, AC-Hly or CyaA) is a key virulence factor of Bordetella pertussis. It targets bactericidal activities of phagocytes, such as oxidative burst and complement- or antibody-mediated opsonophagocytic killing of bacteria. Through cAMP signaling, CyaA also skews TLR-triggered maturation of dendritic cells, inhibiting proinflammatory IL-12 and TNF-α secretion and enhancing IL-10 production and Treg expansion, likely hampering induction of adaptive immune responses to Bordetella infections. Non-enzymatic CyaA toxoid is a potent protective antigen and adjuvant that boosts immunogenicity of co-administered B. pertussis antigens and improves potency of acellular pertussis (aP) vaccines in mice. This makes CyaA a prime antigen candidate for inclusion into a next generation of aP vaccines. Moreover, recombinant CyaA toxoids were recently shown to be safe in humans in frame of Phase I clinical evaluation of a CyaA-based immunotherapeutic vaccine that induces Th1-polarized CD8(+) cytotoxic T-lymphocyte responses targeting cervical tumors.
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Affiliation(s)
- Peter Sebo
- Institute of Microbiology, Academy of Sciences of the Czech Republic, v.v.i, Videnska 1083, 142 20, Prague 4, Czech Republic
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14
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Charge-dependent secretion of an intrinsically disordered protein via the autotransporter pathway. Proc Natl Acad Sci U S A 2013; 110:E4246-55. [PMID: 24145447 DOI: 10.1073/pnas.1310345110] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Autotransporters are a large class of virulence proteins produced by Gram-negative bacteria. They contain an N-terminal extracellular ("passenger") domain that folds into a β-helical structure and a C-terminal β-barrel ("β") domain that anchors the protein to the outer membrane. Because the periplasm lacks ATP, the source of energy that drives passenger domain secretion is unknown. The prevailing model postulates that vectorial folding of the β-helix in the extracellular space facilitates unidirectional secretion of the passenger domain. In this study we used a chimeric protein composed of the 675-residue receptor-binding domain (RD) of the Bordetella pertussis adenylate cyclase toxin CyaA fused to the C terminus of the Escherichia coli O157:H7 autotransporter EspP to test this hypothesis. The RD is a highly acidic, repetitive polypeptide that is intrinsically disordered in the absence of calcium. Surprisingly, we found that the RD moiety was efficiently secreted when it remained in an unfolded conformation. Furthermore, we found that neutralizing or reversing the charge of acidic amino acid clusters stalled translocation in the vicinity of the altered residues. These results challenge the vectorial folding model and, together with the finding that naturally occurring passenger domains are predominantly acidic, provide evidence that a net negative charge plays a significant role in driving the translocation reaction.
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Sotomayor-Pérez AC, Ladant D, Chenal A. Calcium-induced folding of intrinsically disordered repeat-in-toxin (RTX) motifs via changes of protein charges and oligomerization states. J Biol Chem 2011; 286:16997-7004. [PMID: 21454565 DOI: 10.1074/jbc.m110.210393] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Ligand-induced disorder-to-order transition plays a key role in the biological functions of many proteins that contain intrinsically disordered regions. This trait is exhibited by so-called RTX (repeat-in-toxin) motifs found in many virulence factors secreted by numerous gram-negative pathogenic bacteria: RTX proteins are natively disordered in the absence of calcium but fold upon calcium binding. The adenylate cyclase toxin (CyaA) produced by Bordetella pertussis, the causative agent of whooping cough, contains ∼40 RTX motifs organized in five successive blocks separated by non-RTX flanking regions. This RTX domain mediates toxin binding to its eukaryotic cell receptor. We previously showed that the last block of the RTX domain, block V, which is critical for CyaA toxicity, exhibits the hallmarks of intrinsically disordered proteins in the absence of calcium. Moreover, the C-terminal flanking region of CyaA block V is required for its calcium-induced folding. Here, we describe a comprehensive analysis of the hydrodynamic and electrophoretic properties of several block V RTX polypeptides that differ in the presence and/or length of the flanking regions. Our results indicate that the length of the C-terminal flanking region not only controls the calcium-induced folding but also the calcium-induced multimerization of the RTX polypeptides. Moreover, we showed that calcium binding is accompanied by a strong reduction of the net charge of the RTX polypeptides. These data indicate that the disorder-to-order transition in RTX proteins is controlled by a calcium-induced change of the polypeptide charges and stabilized by multimerization.
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Affiliation(s)
- Ana Cristina Sotomayor-Pérez
- Institut Pasteur, CNRS URA 2185, Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, 75724 Paris Cedex 15, France
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16
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Chenal A, Karst JC, Sotomayor Pérez AC, Wozniak AK, Baron B, England P, Ladant D. Calcium-induced folding and stabilization of the intrinsically disordered RTX domain of the CyaA toxin. Biophys J 2011; 99:3744-53. [PMID: 21112299 DOI: 10.1016/j.bpj.2010.10.016] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 10/06/2010] [Accepted: 10/08/2010] [Indexed: 10/18/2022] Open
Abstract
The adenylate cyclase toxin (CyaA) is one of the major virulence factors of Bordetella pertussis, the causative agent of whooping cough. Its C-terminal region, the receptor-binding domain (RD), contains ∼40 calcium-binding Repeat in ToXin (RTX) motifs, which are characteristic of many virulence factors of pathogenic bacteria. We previously showed that RD is intrinsically disordered in the absence of calcium and acquires its functional three-dimensional structure upon calcium binding. To gain further insight into the physicochemical properties of RD, we characterized its calcium-induced conformational and stability changes by combining spectroscopic approaches. We show that RD, in the absence of calcium, adopts premolten globule conformations, due in part to the strong internal electrostatic repulsions between the negative charges of the aspartate-rich polypeptide sequence. Accordingly, sodium is able to screen these electrostatic repulsions, allowing a partial compaction of the polypeptide, whereas calcium triggers a strong compaction as well as the acquisition of secondary and tertiary structures in a highly cooperative manner. The differential sensitivity of the calcium-loaded state to guanidinium- and urea-induced denaturations provides further evidence that electrostatic interactions play a critical role in the folding and stability of RD. These results provide new insights into the folding/function relationship of the RTX motifs.
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Affiliation(s)
- Alexandre Chenal
- Unite de Biochimie des Interactions Macromoléculaires, Institut Pasteur, Centre National de la Recherche Scientifique URA 2185, Paris, France.
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17
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Linhartová I, Bumba L, Mašín J, Basler M, Osička R, Kamanová J, Procházková K, Adkins I, Hejnová-Holubová J, Sadílková L, Morová J, Sebo P. RTX proteins: a highly diverse family secreted by a common mechanism. FEMS Microbiol Rev 2011; 34:1076-112. [PMID: 20528947 PMCID: PMC3034196 DOI: 10.1111/j.1574-6976.2010.00231.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Repeats-in-toxin (RTX) exoproteins of Gram-negative bacteria form a steadily growing family of proteins with diverse biological functions. Their common feature is the unique mode of export across the bacterial envelope via the type I secretion system and the characteristic, typically nonapeptide, glycine- and aspartate-rich repeats binding Ca2+ ions. In this review, we summarize the current state of knowledge on the organization of rtx loci and on the biological and biochemical activities of therein encoded proteins. Applying several types of bioinformatic screens on the steadily growing set of sequenced bacterial genomes, over 1000 RTX family members were detected, with the biological functions of most of them remaining to be characterized. Activities of the so far characterized RTX family members are then discussed and classified according to functional categories, ranging from the historically first characterized pore-forming RTX leukotoxins, through the large multifunctional enzymatic toxins, bacteriocins, nodulation proteins, surface layer proteins, up to secreted hydrolytic enzymes exhibiting metalloprotease or lipase activities of industrial interest.
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Affiliation(s)
- Irena Linhartová
- Institute of Microbiology AS CR v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
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18
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Eby JC, Ciesla WP, Hamman W, Donato GM, Pickles RJ, Hewlett EL, Lencer WI. Selective translocation of the Bordetella pertussis adenylate cyclase toxin across the basolateral membranes of polarized epithelial cells. J Biol Chem 2010; 285:10662-70. [PMID: 20139088 DOI: 10.1074/jbc.m109.089219] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The catalytic domain of Bordetella pertussis adenylate cyclase toxin (ACT) translocates directly across the plasma membrane of mammalian cells to induce toxicity by the production of cAMP. Here, we use electrophysiology to examine the translocation of toxin into polarized epithelial cells that model the mucosal surfaces of the host. We find that both polarized T84 cell monolayers and human airway epithelial cultures respond to nanomolar concentrations of ACT when applied to basolateral membranes, with little or no response to toxin applied apically. The induction of toxicity is rapid and fully explained by increases in intracellular cAMP, consistent with toxin translocation directly across the basolateral membrane. Intoxication of T84 cells occurs in the absence of CD11b/CD18 or evidence of another specific membrane receptor, and it is not dependent on post-translational acylation of the toxin or on host cell membrane potential, both previously reported to be required for toxin action. Thus, elements of the basolateral membrane render epithelial cells highly sensitive to the entry of ACT in the absence of a specific receptor for toxin binding.
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Affiliation(s)
- Joshua C Eby
- Division of Infectious Diseases and International Health, Department of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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19
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Sotomayor Pérez AC, Karst JC, Davi M, Guijarro JI, Ladant D, Chenal A. Characterization of the regions involved in the calcium-induced folding of the intrinsically disordered RTX motifs from the bordetella pertussis adenylate cyclase toxin. J Mol Biol 2010; 397:534-49. [PMID: 20096704 DOI: 10.1016/j.jmb.2010.01.031] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 12/22/2009] [Accepted: 01/12/2010] [Indexed: 11/25/2022]
Abstract
Repeat in toxin (RTX) motifs are nonapeptide sequences found among numerous virulence factors of Gram-negative bacteria. In the presence of calcium, these RTX motifs are able to fold into an idiosyncratic structure called the parallel beta-roll. The adenylate cyclase toxin (CyaA) produced by Bordetella pertussis, the causative agent of whooping cough, is one of the best-characterized RTX cytolysins. CyaA contains a C-terminal receptor domain (RD) that mediates toxin binding to the eukaryotic cell receptor. The receptor-binding domain is composed of about forty RTX motifs organized in five successive blocks (I to V). The RTX blocks are separated by non-RTX flanking regions of variable lengths. It has been shown that block V with its N- and C-terminal flanking regions constitutes an autonomous subdomain required for the toxicity of CyaA. Here, we investigated the calcium-induced biophysical changes of this subdomain to identify the respective contributions of the flanking regions to the folding process of the RTX motifs. We showed that the RTX polypeptides, in the absence of calcium, exhibited the hallmarks of intrinsically disordered proteins and that the C-terminal flanking region was critical for the calcium-dependent folding of the RTX polypeptides, while the N-terminal flanking region was not involved. Furthermore, the secondary and tertiary structures were acquired concomitantly upon cooperative binding of several calcium ions. This suggests that the RTX polypeptide folding is a two-state reaction, from a calcium-free unfolded state to a folded and compact conformation, in which the calcium-bound RTX motifs adopt a beta-roll structure. The relevance of these results to the toxin physiology, in particular to its secretion, is discussed.
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Affiliation(s)
- Ana-Cristina Sotomayor Pérez
- Unité de Biochimie des Interactions Macromoléculaires, Département de Biologie Structurale et Chimie, CNRS URA 2185, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris cedex 15, France
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20
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Szilvay GR, Blenner MA, Shur O, Cropek DM, Banta S. A FRET-based method for probing the conformational behavior of an intrinsically disordered repeat domain from Bordetella pertussis adenylate cyclase. Biochemistry 2009; 48:11273-82. [PMID: 19860484 DOI: 10.1021/bi901447j] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A better understanding of the conformational changes exhibited by intrinsically disordered proteins is necessary as we continue to unravel their myriad biological functions. In repeats in toxin (RTX) domains, calcium binding triggers the natively unstructured domain to adopt a beta roll structure. Here we present an in vitro Forster resonance energy transfer (FRET)-based method for the investigation of the conformational behavior of an RTX domain from the Bordetella pertussis adenylate cyclase consisting of nine repeat units. Equilibrium and stopped-flow FRET between fluorescent proteins, attached to the termini of the domain, were measured in an analysis of the end-to-end distance changes in the RTX domain. The method was complemented with circular dichroism spectroscopy, tryptophan fluorescence, and bis-ANS dye binding. High ionic strength was observed to decrease the calcium affinity of the RTX domain. A truncation and single amino acid mutations yielded insights into the structural determinants of beta roll formation. Mutating the conserved Asp residue in one of the nine repeats significantly reduced the affinity of the domains for calcium ions. Removal of the sequences flanking the repeat domain prevented folding, but replacing them with fluorescent proteins restored the conformational behavior, suggesting an entropic stabilization. The FRET-based method is a useful technique that complements other low-resolution techniques for investigating the dynamic conformational behavior of the RTX domain and other intrinsically disordered protein domains.
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Affiliation(s)
- Géza R Szilvay
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, New York, New York 10027, USA
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21
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Vojtova-Vodolanova J, Basler M, Osicka R, Knapp O, Maier E, Cerny J, Benada O, Benz R, Sebo P. Oligomerization is involved in pore formation by
Bordetella
adenylate cyclase toxin. FASEB J 2009; 23:2831-43. [DOI: 10.1096/fj.09-131250] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Marek Basler
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Radim Osicka
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Oliver Knapp
- Lehrstuhl für Biotechnologie Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg Würzburg Federal Republic of Germany
| | - Elke Maier
- Lehrstuhl für Biotechnologie Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg Würzburg Federal Republic of Germany
| | - Jan Cerny
- Department of Cell Biology Faculty of Science Charles University Prague Czech Republic
| | - Oldrich Benada
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
| | - Roland Benz
- Lehrstuhl für Biotechnologie Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg Würzburg Federal Republic of Germany
| | - Peter Sebo
- Institute of Microbiology Academy of Sciences of the Czech Republic Prague Czech Republic
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22
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Xu F, Chen X, Shi A, Yang B, Wang J, Li Y, Guo X, Blackall PJ, Yang H. Characterization and immunogenicity of an apxIA mutant of Actinobacillus pleuropneumoniae. Vet Microbiol 2006; 118:230-9. [PMID: 16930871 DOI: 10.1016/j.vetmic.2006.07.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Revised: 07/09/2006] [Accepted: 07/13/2006] [Indexed: 12/01/2022]
Abstract
Actinobacillus pleuropneumoniae is the aetiological agent of porcine pleuropneumonia, a highly contagious and often fatal disease. A candidate live vaccine strain, potentially capable of cross-serovar protection, was constructed by deleting the section of the apxIA gene coding for the C-terminal segment of ApxI toxin of the A. pleuropneumoniae serovar 10 reference strain (D13039) and inserting a chloramphenicol resistance gene cassette. The mutant strain (termed D13039A(-)Chl(r)) produced an approximately 48kDa protein corresponding to the N-terminus of the ApxI toxin, and exhibited no haemolytic activity and lower virulence in mice compared with the parental strain. The mutant was evaluated in a vaccination-challenge trial in which pigs were given two intra-nasal doses of the mutant at 14 days intervals and then challenged 14 days after the last vaccination with either A. pleuropneumoniae serovar 1 (4074) or serovar 2 (S1536) or serovar 10 (D13039) reference strains. The haemolysin neutralisation titres of the pre-challenge sera were significantly higher in the vaccinated pigs than in the unvaccinated pigs. The mortalities, clinical signs and lung lesion scores in the vaccinated pigs were significantly lower than those in the unvaccinated pigs for the serovar 1 challenge. A significantly lower lung lesion score was also observed in the vaccinated pigs, compared with unvaccinated pigs, for serovar 2 challenge. Our work suggests that the mutant strain offers potential as a live attenuated pleuropneumonia vaccine that can provide cross-serovar protection.
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Affiliation(s)
- Fuzhou Xu
- Key Laboratory of Preventive Veterinary Medicine of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Haidian District, Beijing, China
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23
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Bauche C, Chenal A, Knapp O, Bodenreider C, Benz R, Chaffotte A, Ladant D. Structural and Functional Characterization of an Essential RTX Subdomain of Bordetella pertussis Adenylate Cyclase Toxin. J Biol Chem 2006; 281:16914-16926. [PMID: 16627468 DOI: 10.1074/jbc.m601594200] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] 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 by a unique mechanism that consists in a calcium-dependent, direct translocation of the CyaA catalytic domain across the plasma membrane of the target cells. CyaA possesses a series of a glycine- and aspartate-rich nonapeptide repeats (residues 1006-1613) of the prototype GGXG(N/D)DX(L/I/F)X (where X represents any amino acid) that are characteristic of the RTX (repeat in toxin) family of bacterial cytolysins. These repeats are arranged in a tandem fashion and may fold into a characteristic parallel beta-helix or beta-roll motif that constitutes a novel type of calcium binding structure, as revealed by the three-dimensional structure of the Pseudomonas aeruginosa alkaline protease. Here we have characterized the structure-function relationships of various fragments from the CyaA RTX subdomain. Our results indicate that the RTX functional unit includes both the tandem repeated nonapeptide motifs and the adjacent polypeptide segments, which are essential for the folding and calcium responsiveness of the RTX module. Upon calcium binding to the RTX repeats, a conformational rearrangement of the adjacent non-RTX sequences may act as a critical molecular switch to trigger the CyaA entry into target cells.
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Affiliation(s)
- Cécile Bauche
- Unité de Biochimie des Interactions Macromoléculaires, CNRS URA 2185, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Alexandre Chenal
- Unité de Biochimie des Interactions Macromoléculaires, CNRS URA 2185, Institut Pasteur, 75724 Paris Cedex 15, France
| | - Oliver Knapp
- Lehrstuhl für Biotechnologie, Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg, Am Hubland, D-97074 Würzburg, Federal Republic of Germany
| | - Christophe Bodenreider
- Abteilung Biophysikalische Chemie, Biozentrum der Universität Basel, CH-4056 Basel, Switzerland
| | - Roland Benz
- Lehrstuhl für Biotechnologie, Theodor-Boveri-Institut (Biozentrum) der Universität Würzburg, Am Hubland, D-97074 Würzburg, Federal Republic of Germany
| | - Alain Chaffotte
- UnitédeRésonance Magnétique Nucléaire des Biomolécules, CNRS URA 2185, Institut Pasteur, F-75724 Paris, France
| | - Daniel Ladant
- Unité de Biochimie des Interactions Macromoléculaires, CNRS URA 2185, Institut Pasteur, 75724 Paris Cedex 15, France.
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24
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Vojtová J, Kofronová O, Sebo P, Benada O. Bordetella adenylate cyclase toxin induces a cascade of morphological changes of sheep erythrocytes and localizes into clusters in erythrocyte membranes. Microsc Res Tech 2006; 69:119-29. [PMID: 16456835 DOI: 10.1002/jemt.20277] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Adenylate cyclase toxin (CyaA) of Bordetella pertussis penetrates the membrane of eukaryotic cells, producing high levels of intracellular cAMP, as well as hemolysis that results from the formation of cation-selective toxin channels in the membrane. Using several microscopical approaches we studied the effects of CyaA action on the morphology of sheep erythrocytes during early phases preceding lysis and examined localization of CyaA molecules within the erythrocyte membrane. CyaA induced a cascade of morphological changes of erythrocytes, such as shrinkage, formation of membrane projections, and blebs and swelling. The use of an enzymatically inactive CyaA-AC- toxoid that is unable to produce cAMP and of a CyaA-E581K mutant exhibiting higher hemolytic activity than with CyaA showed that the hemolytic activity is responsible for the induction of morphological changes of erythrocytes. Further, immunolabeling of inserted CyaA-232/FLAG molecules with specific anti-FLAG antibodies and IgG-gold particles indicated a clustered distribution of CyaA molecules in erythrocyte membrane. This was confirmed by immunofluorescence and confocal microscopy, which revealed uniform stoichiometry of CyaA clusters, suggesting CyaA binding into specific domains in erythrocyte membrane. Indeed, a decrease of CyaA binding after cholesterol depletion of erythrocytes suggests toxin targeting and binding to membrane microdomains (rafts).
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Affiliation(s)
- Jana Vojtová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 142 20, Prague 4, Czech Republic
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25
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Lee SJ, Gray MC, Zu K, Hewlett EL. Oligomeric behavior of Bordetella pertussis adenylate cyclase toxin in solution. Arch Biochem Biophys 2005; 438:80-7. [PMID: 15878155 DOI: 10.1016/j.abb.2005.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 03/31/2005] [Accepted: 04/02/2005] [Indexed: 10/25/2022]
Abstract
Adenylate cyclase (AC) toxin from Bordetella pertussis inserts into eukaryotic cells, producing intracellular cAMP, as well as hemolysis and cytotoxicity. Concentration dependence of hemolysis suggests oligomers as the functional unit and inactive deletion mutants permit partial restoration of intoxication and/or hemolysis, when added in pairs [M. Iwaki, A. Ullmann, P. Sebo, Mol. Microbiol. 17 (1995) 1015-1024], suggesting dimerization/oligomerization. Using affinity co-precipitation and fluorescence resonance energy transfer (FRET), we demonstrate specific self-association of AC toxin molecules in solution. Flag-tagged AC toxin mixed with biotinylated-AC toxin, followed by streptavidin beads, yields both forms of the toxin. FRET measurements of toxin, labeled with different fluorophores, demonstrate association in solution, requiring post-translational acylation, but not calcium. AC toxin mixed with DeltaR, an inactive mutant, results in enhancement of hemolysis over that with wild type alone, suggesting that oligomers are functional. Dimers and perhaps higher molecular mass forms of AC toxin occur in solution in a manner that is relevant to toxin action.
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Affiliation(s)
- Sang-Jin Lee
- University of Virginia, Department of Pharmacology, Charlottesville, VA 22903, USA
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26
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Cortajarena AL, Goni FM, Ostolaza H. A receptor-binding region in Escherichia coli alpha-haemolysin. J Biol Chem 2003; 278:19159-63. [PMID: 12582172 DOI: 10.1074/jbc.m208552200] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli alpha-hemolysin (HlyA) is a 107-kDa protein toxin with a wide range of mammalian target cells. Previous work has shown that glycophorin is a specific receptor for HlyA in red blood cells (Cortajarena, A. L., Goñi, F. M., and Ostolaza, H. (2001) J. Biol. Chem. 276, 12513-12519). The present study was aimed at identifying the glycophorin-binding region in the toxin. Data in the literature pointed to a short amino acid sequence near the C terminus as a putative receptor-binding domain. Previous sequence analyses of several homologous toxins that belong, like HlyA, to the so-called RTX toxin family revealed a conserved region that corresponded to residues 914-936 of HlyA. We therefore prepared a deletion mutant lacking these residues (HlyA Delta 914-936) and found that its hemolytic activity was decreased by 10,000-fold with respect to the wild type. This deletion mutant was virtually unable to bind human and horse red blood cells or to bind pure glycophorin in an affinity column. The peptide Trp914-Arg936 had no lytic activity of its own, but it could bind glycophorin reconstituted in lipid vesicles. Moreover, the peptide Trp914-Arg936 protected red blood cells from hemolysis induced by wild type HlyA. It was concluded that amino acid residues 914-936 constitute a major receptor-binding region in alpha-hemolysin.
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Affiliation(s)
- Aitziber L Cortajarena
- Unidad de Biofísica, Consejo Superior de Investigaciones Científicas-Euskal Herriko Unibertsitatea and Departamento de Bioquímica, Universidad del País Vasco, Aptdo. 644, 48080 Bilbao, Spain
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27
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Shen Y, Lee YS, Soelaiman S, Bergson P, Lu D, Chen A, Beckingham K, Grabarek Z, Mrksich M, Tang WJ. Physiological calcium concentrations regulate calmodulin binding and catalysis of adenylyl cyclase exotoxins. EMBO J 2002; 21:6721-32. [PMID: 12485993 PMCID: PMC139101 DOI: 10.1093/emboj/cdf681] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Edema factor (EF) and CyaA are calmodulin (CaM)-activated adenylyl cyclase exotoxins involved in the pathogenesis of anthrax and whooping cough, respectively. Using spectroscopic, enzyme kinetic and surface plasmon resonance spectroscopy analyses, we show that low Ca(2+) concentrations increase the affinity of CaM for EF and CyaA causing their activation, but higher Ca(2+) concentrations directly inhibit catalysis. Both events occur in a physiologically relevant range of Ca(2+) concentrations. Despite the similarity in Ca(2+) sensitivity, EF and CyaA have substantial differences in CaM binding and activation. CyaA has 100-fold higher affinity for CaM than EF. CaM has N- and C-terminal globular domains, each binding two Ca(2+) ions. CyaA can be fully activated by CaM mutants with one defective C-terminal Ca(2+)-binding site or by either terminal domain of CaM while EF cannot. EF consists of a catalytic core and a helical domain, and both are required for CaM activation of EF. Mutations that decrease the interaction of the helical domain with the catalytic core create an enzyme with higher sensitivity to Ca(2+)-CaM activation. However, CyaA is fully activated by CaM without the domain corresponding to the helical domain of EF.
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Affiliation(s)
- Yuequan Shen
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Young-Sam Lee
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Sandriyana Soelaiman
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Pamela Bergson
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Dan Lu
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Alice Chen
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Kathy Beckingham
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Zenon Grabarek
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Milan Mrksich
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
| | - Wei-Jen Tang
- Ben-May Institute for Cancer Research, Department of Chemistry, and Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, Department of Biochemistry and Cell Biology, Rice University, Houston, TX 77251 and Boston Biomedical Research Institute, Watertown, MA 02472, USA Corresponding author e-mail:
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Rhodes CR, Gray MC, Watson JM, Muratore TL, Kim SB, Hewlett EL, Grisham CM. Structural consequences of divalent metal binding by the adenylyl cyclase toxin of Bordetella pertussis. Arch Biochem Biophys 2001; 395:169-76. [PMID: 11697853 DOI: 10.1006/abbi.2001.2553] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adenylyl cyclase toxin of Bordetella pertussis has been shown by several investigators to require Ca(2+) for its actions on target cells, but little is known about the nature and specificity of divalent metal binding to this novel toxin. Calcium is the preferred divalent metal since toxic actions are markedly reduced in the presence of divalent species other than calcium. Mn(2+) EPR was used to quantitate and characterize divalent metal binding and revealed that the toxin contains approximately 40 divalent metal sites, consisting of at least one class of high-affinity sites that bind Mn(2+) with a K(D) of 0.05 to 0.35 microM and one or more classes of lower affinity sites. Water proton relaxation data indicate that approximately 30 of these sites are completely inaccessible to bulk solvent. Our observations, together with the sequence homology between adenylyl cyclase toxin and the alkaline protease of Pseudomonas aeruginosa, indicate that the formation of five beta-sheet helices within the repeat domain of the toxin upon binding Ca(2+) is required for cell intoxication.
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Affiliation(s)
- C R Rhodes
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22906, USA
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Iwaki M, Kamachi K, Konda T. Stimulation of Bordetella pertussis adenylate cyclase toxin intoxication by its hemolysin domain. Infect Immun 2000; 68:3727-30. [PMID: 10816536 PMCID: PMC97667 DOI: 10.1128/iai.68.6.3727-3730.2000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The internalization of the N-terminal catalytic domain of Bordetella pertussis adenylate cyclase toxin (ACT) across the cytoplasmic membrane has been considered to occur independently from protein-protein interactions which can lead to oligomerization required for hemolytic activity by its C-terminal hemolysin domain. Here we report that when added in excess, this hemolysin domain stimulates the internalization, suggesting the involvement of protein-protein interactions in cell-invasive activity of ACT, as well as its hemolytic activity.
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Affiliation(s)
- M Iwaki
- Department of Bacterial and Blood Products, National Institute of Infectious Diseases, Musashimurayama-shi, Tokyo 208-0011, Japan.
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Osicka R, Osicková A, Basar T, Guermonprez P, Rojas M, Leclerc C, Sebo P. Delivery of CD8(+) T-cell epitopes into major histocompatibility complex class I antigen presentation pathway by Bordetella pertussis adenylate cyclase: delineation of cell invasive structures and permissive insertion sites. Infect Immun 2000; 68:247-56. [PMID: 10603395 PMCID: PMC97128 DOI: 10.1128/iai.68.1.247-256.2000] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/1999] [Accepted: 10/19/1999] [Indexed: 11/20/2022] Open
Abstract
Bordetella pertussis adenylate cyclase (AC) toxin-hemolysin (ACT-Hly) can penetrate a variety of eukaryotic cells. Recombinant AC toxoids have therefore been recently used for delivery of CD8(+) T-cell epitopes into antigen-presenting cells in vivo and for induction of protective antiviral, as well as therapeutic antitumor cytotoxic T-cell responses. We have explored the carrier potential of the ACT molecule by insertional mutagenesis scanning for new permissive sites, at which integration of two- to nine-residue-long peptides does not interfere with membrane interaction and translocation of ACT. A model CD8(+) T-cell epitope of ovalbumin was incorporated at 10 of these permissive sites along the toxin molecule, and the capacity of ACT constructs to penetrate into cell cytosol and deliver the epitope into the major histocompatibility complex (MHC) class I antigen processing and presentation pathway was examined. While all six constructs bearing the epitope within the Hly portion of ACT failed to deliver the epitope to the MHC class I molecules, all four toxoids with inserts within different permissive sites in the AC domain efficiently delivered the epitope into this cytosolic pathway, giving rise to stimulation of a specific CD8(+) T-cell hybridoma. The results suggest that, in contrast to the AC domain, the hemolysin moiety of ACT does not reach the cytosolic entry of the MHC class I pathway.
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Affiliation(s)
- R Osicka
- Cellular and Molecular Microbiology Division, Institute of Microbiology of the Academy of Sciences of the Czech Republic, CZ-142 20 Prague 4, Czech Republic
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