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Proctor EJ, Frost HR, Satapathy S, Botquin G, Urbaniec J, Gorman J, De Oliveira DMP, McArthur J, Davies MR, Botteaux A, Smeesters P, Sanderson-Smith M. Molecular characterization of the interaction between human IgG and the M-related proteins from Streptococcus pyogenes. J Biol Chem 2024; 300:105623. [PMID: 38176650 PMCID: PMC10844976 DOI: 10.1016/j.jbc.2023.105623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/04/2023] [Accepted: 12/20/2023] [Indexed: 01/06/2024] Open
Abstract
Group A Streptococcal M-related proteins (Mrps) are dimeric α-helical-coiled-coil cell membrane-bound surface proteins. During infection, Mrp recruit the fragment crystallizable region of human immunoglobulin G via their A-repeat regions to the bacterial surface, conferring upon the bacteria enhanced phagocytosis resistance and augmented growth in human blood. However, Mrps show a high degree of sequence diversity, and it is currently not known whether this diversity affects the Mrp-IgG interaction. Herein, we report that diverse Mrps all bind human IgG subclasses with nanomolar affinity, with differences in affinity which ranged from 3.7 to 11.1 nM for mixed IgG. Using surface plasmon resonance, we confirmed Mrps display preferential IgG-subclass binding. All Mrps were found to have a significantly weaker affinity for IgG3 (p < 0.05) compared to all other IgG subclasses. Furthermore, plasma pulldown assays analyzed via Western blotting revealed that all Mrp were able to bind IgG in the presence of other serum proteins at both 25 °C and 37 °C. Finally, we report that dimeric Mrps bind to IgG with a 1:1 stoichiometry, enhancing our understanding of this important host-pathogen interaction.
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Affiliation(s)
- Emma-Jayne Proctor
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia
| | - Hannah R Frost
- Molecular Bacteriology Laboratory, European Plotkins Institute for Vaccinology (EPIV), Université Libre de Bruxelles, Brussels, Belgium
| | - Sandeep Satapathy
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia; The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Gwenaëlle Botquin
- Molecular Bacteriology Laboratory, European Plotkins Institute for Vaccinology (EPIV), Université Libre de Bruxelles, Brussels, Belgium
| | - Joanna Urbaniec
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia
| | - Jody Gorman
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia
| | - David M P De Oliveira
- The University of Queensland, School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre, QLD, Australia
| | - Jason McArthur
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia
| | - Mark R Davies
- Department of Microbiology and Immunology, at the Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Victoria, Australia
| | - Anne Botteaux
- Molecular Bacteriology Laboratory, European Plotkins Institute for Vaccinology (EPIV), Université Libre de Bruxelles, Brussels, Belgium
| | - Pierre Smeesters
- Molecular Bacteriology Laboratory, European Plotkins Institute for Vaccinology (EPIV), Université Libre de Bruxelles, Brussels, Belgium
| | - Martina Sanderson-Smith
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, Australia.
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Abstract
M and M-like proteins are major virulence factors of the widespread and potentially deadly bacterial pathogen Streptococcus pyogenes. These proteins confer resistance against innate and adaptive immune responses by recruiting specific human proteins to the streptococcal surface. Nonimmune recruitment of immunoglobulins G (IgG) and A (IgA) through their fragment crystallizable (Fc) domains by M and M-like proteins was described almost 40 years ago, but its impact on virulence remains unresolved. These interactions have been suggested to be consequential under immune conditions at mucosal surfaces and in secretions but not in plasma, while other evidence suggests importance in evading phagocytic killing in nonimmune blood. Recently, an indirect effect of Fc-binding through ligand-induced stabilization of an M-like protein was shown to increase virulence. Nonimmune recruitment has also been seen to contribute to tissue damage in animal models of autoimmune diseases triggered by S. pyogenes infection. The damage was treatable by targeting Fc-binding. This and other potential therapeutic applications warrant renewed attention to Fc-binding by M and M-like proteins.
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Affiliation(s)
- Jori O. Mills
- Department of Chemistry & Biochemistry, La Jolla, California, United States of America
| | - Partho Ghosh
- Department of Chemistry & Biochemistry, La Jolla, California, United States of America
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Frost HR, Sanderson-Smith M, Walker M, Botteaux A, Smeesters PR. Group A streptococcal M-like proteins: From pathogenesis to vaccine potential. FEMS Microbiol Rev 2018; 42:193-204. [PMID: 29228173 DOI: 10.1093/femsre/fux057] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/06/2017] [Indexed: 12/27/2022] Open
Abstract
M and M-like surface proteins from group A Streptococcus (GAS) act as virulence factors and have been used in multiple vaccine candidates. While the M protein has been extensively studied, the two genetically and functionally related M-like proteins, Mrp and Enn, although present in most streptococcal strains have been relatively less characterised. We compile the current state of knowledge for these two proteins, from discovery to recent studies on function and immunogenicity, using the M protein for comparison as a prototype of this family of proteins. We focus on the known interactions between M-like proteins and host ligand proteins, and analyse the genetic data supporting these interactions. We discuss known and possible functions of M-like proteins during GAS infections, and highlight knowledge gaps where further investigation is warranted.
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Affiliation(s)
- Hannah R Frost
- Molecular Bacteriology Laboratory, Université Libre de Bruxelles, Brussels 1070, Belgium.,Group A Streptococcus Research Group, Murdoch Children's Research Institute, Melbourne 3052, VIC, Australia
| | - Martina Sanderson-Smith
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, 2522, NSW, Australia
| | - Mark Walker
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia 4072, QLD, Australia
| | - Anne Botteaux
- Molecular Bacteriology Laboratory, Université Libre de Bruxelles, Brussels 1070, Belgium
| | - Pierre R Smeesters
- Molecular Bacteriology Laboratory, Université Libre de Bruxelles, Brussels 1070, Belgium.,Group A Streptococcus Research Group, Murdoch Children's Research Institute, Melbourne 3052, VIC, Australia.,Department of Pediatrics, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels 1020, Belgium.,Centre for International Child Health, University of Melbourne, Melbourne 3052, VIC, Australia
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4
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Sanderson-Smith M, De Oliveira DMP, Guglielmini J, McMillan DJ, Vu T, Holien JK, Henningham A, Steer AC, Bessen DE, Dale JB, Curtis N, Beall BW, Walker MJ, Parker MW, Carapetis JR, Van Melderen L, Sriprakash KS, Smeesters PR. A systematic and functional classification of Streptococcus pyogenes that serves as a new tool for molecular typing and vaccine development. J Infect Dis 2014; 210:1325-38. [PMID: 24799598 PMCID: PMC6083926 DOI: 10.1093/infdis/jiu260] [Citation(s) in RCA: 228] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/25/2014] [Indexed: 11/12/2022] Open
Abstract
Streptococcus pyogenes ranks among the main causes of mortality from bacterial infections worldwide. Currently there is no vaccine to prevent diseases such as rheumatic heart disease and invasive streptococcal infection. The streptococcal M protein that is used as the substrate for epidemiological typing is both a virulence factor and a vaccine antigen. Over 220 variants of this protein have been described, making comparisons between proteins difficult, and hindering M protein-based vaccine development. A functional classification based on 48 emm-clusters containing closely related M proteins that share binding and structural properties is proposed. The need for a paradigm shift from type-specific immunity against S. pyogenes to emm-cluster based immunity for this bacterium should be further investigated. Implementation of this emm-cluster-based system as a standard typing scheme for S. pyogenes will facilitate the design of future studies of M protein function, streptococcal virulence, epidemiological surveillance, and vaccine development.
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Affiliation(s)
- Martina Sanderson-Smith
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Australia
| | - David M. P. De Oliveira
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Australia
| | - Julien Guglielmini
- Microbial Evolutionary Genomics, Département Génomes et Génétique, Institut Pasteur
- CNRS, UMR3525, Paris, France
| | - David J. McMillan
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, Brisbane
- Inflammation and Healing Research Cluster, School of Health and Sports Sciences, University of the Sunshine Coast, Sippy Downs, Australia
| | - Therese Vu
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, Brisbane
- Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Jessica K. Holien
- Biota Structural Biology Laboratory, ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Melbourne
| | - Anna Henningham
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane
| | - Andrew C. Steer
- Murdoch Children Research Institute
- Centre for International Child Health, The University of Melbourne
- Department of General Medicine, Royal Children's Hospital Melbourne, Australia
| | - Debra E. Bessen
- Department of Microbiology and Immunology, New York Medical College, Valhalla
| | - James B. Dale
- Department of Medicine, The University of Tennessee Health Science Center
- Department of Veterans Affairs Medical Center, and
- Department of Microbiology, Immunology and Biochemistry, The University of Tennessee Health Science Center, Memphis
| | - Nigel Curtis
- Murdoch Children Research Institute
- Infectious Diseases Unit, Royal Children's Hospital Melbourne
- Department of Paediatrics, The University of Melbourne, Australia
| | - Bernard W. Beall
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Mark J. Walker
- School of Chemistry and Molecular Biosciences and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane
| | - Michael W. Parker
- Biota Structural Biology Laboratory, ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Melbourne
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne
| | - Jonathan R. Carapetis
- Telethon Institute for Child Health Research, Centre for Child Health Research, University of Western Australia, Perth
| | - Laurence Van Melderen
- Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium
| | - Kadaba S. Sriprakash
- Bacterial Pathogenesis Laboratory, QIMR Berghofer Medical Research Institute, Brisbane
| | - Pierre R. Smeesters
- Laboratoire de Génétique et Physiologie Bactérienne, Institut de Biologie et de Médecine Moléculaires, Faculté des Sciences, Université Libre de Bruxelles, Gosselies, Belgium
- Murdoch Children Research Institute
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Non-immune binding of human IgG to M-related proteins confers resistance to phagocytosis of group A streptococci in blood. PLoS One 2013; 8:e78719. [PMID: 24205299 PMCID: PMC3808296 DOI: 10.1371/journal.pone.0078719] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/20/2013] [Indexed: 12/04/2022] Open
Abstract
The non-immune binding of immunoglobulins by bacteria is thought to contribute to the pathogenesis of infections. M-related proteins (Mrp) are group A streptococcal (GAS) receptors for immunoglobulins, but it is not known if this binding has any impact on virulence. To further investigate the binding of immunoglobulins to Mrp, we engineered mutants of an M type 4 strain of GAS by inactivating the genes for mrp, emm, enn, sof, and sfbX and tested these mutants in IgG-binding assays. Inactivation of mrp dramatically decreased the binding of human IgG, whereas inactivation of emm, enn, sof, and sfbx had only minor effects, indicating that Mrp is a major IgG-binding protein. Binding of human immunoglobulins to a purified, recombinant form of Mrp indicated that it selectively binds to the Fc domain of human IgG, but not IgA or IgM and that it preferentially bound subclasses IgG1>IgG4>IgG2>IgG3. Recombinant proteins encompassing different regions of Mrp were engineered and used to map its IgG-binding domain to its A-repeat region and a recombinant protein with 3 A-repeats was a better inhibitor of IgG binding than one with a single A-repeat. A GAS mutant expressing Mrp with an in-frame deletion of DNA encoding the A-repeats had a dramatically reduced ability to bind human IgG and to grow in human blood. Mrp exhibited host specificity in binding IgG; human IgG was the best inhibitor of the binding of IgG followed by pig, horse, monkey, and rabbit IgG. IgG from goat, mouse, rat, cow, donkey, chicken, and guinea pig were poor inhibitors of binding. These findings indicate that Mrp preferentially binds human IgG and that this binding contributes to the ability of GAS to resist phagocytosis and may be a factor in the restriction of GAS infections to the human host.
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Meehan M, Lewis MJ, Byrne C, O'Hare D, Woof JM, Owen P. Localization of the equine IgG-binding domain in the fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi. MICROBIOLOGY-SGM 2009; 155:2583-2592. [PMID: 19423628 DOI: 10.1099/mic.0.028845-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fibrinogen-binding protein (FgBP, also termed SeM) is a cell-wall-associated anti-phagocytic M-like protein of the equine pathogen Streptococcus equi subsp. equi, and binds fibrinogen (Fg) and IgG. FgBP binds Fg avidly through residues located at the extreme N terminus of the molecule, whereas the IgG-binding site is more centrally located between the A and B repeats. FgBP binds equine IgG4 and IgG7 subclasses through interaction with the CH2-CH3 interdomain region of IgG-Fc, and possesses overlapping Fc-binding sites with protein A and protein G. In this study, FgBP truncates containing defined internal deletions were used to identify a stretch of 14 aa (residues 335-348) critical for IgG binding. Protein chimeras consisting of the non-IgG-binding alpha-helical coiled-coil M5 protein fused to FgBP sequences were used to identify a minimal equine IgG-binding domain consisting of residues 329-360. Competition ELISA tests suggested that IgG does not compromise Fg binding and vice versa.
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Affiliation(s)
- Mary Meehan
- Department of Microbiology, Moyne Institute of Preventative Medicine, Trinity College, Dublin 2, Ireland
| | - Melanie J Lewis
- Division of Medical Sciences, University of Dundee Medical School, Ninewells Hospital, Dundee DD1 9SY, UK
| | - Caroline Byrne
- Department of Microbiology, Moyne Institute of Preventative Medicine, Trinity College, Dublin 2, Ireland
| | - David O'Hare
- Department of Microbiology, Moyne Institute of Preventative Medicine, Trinity College, Dublin 2, Ireland
| | - Jenny M Woof
- Division of Medical Sciences, University of Dundee Medical School, Ninewells Hospital, Dundee DD1 9SY, UK
| | - Peter Owen
- Department of Microbiology, Moyne Institute of Preventative Medicine, Trinity College, Dublin 2, Ireland
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7
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Tagawa Y, Sanders JD, Uchida I, Bastida-Corcuera FD, Kawashima K, Corbeil LB. Genetic and functional analysis of Haemophilus somnus high molecular weight-immunoglobulin binding proteins. Microb Pathog 2005; 39:159-70. [PMID: 16169703 DOI: 10.1016/j.micpath.2005.08.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 08/03/2005] [Indexed: 11/23/2022]
Abstract
Haemophilus somnus immunoglobulin binding proteins (IgBPs) are virulence associated but only one (p76) has been genetically defined. We determined the nucleotide sequence of the 5'-flanking region of the p76 gene. This region had been identified as the coding region for a series of high molecular weight (HMW)-IgBPs. Analysis of the nucleotide sequence indicated the gene (immunoglobulin binding protein A, ibpA) encoding the HMW and p76 IgBPs comprised a single open reading frame of 12,285 base pairs (bp). The ibpA gene is flanked by an upstream ORF of 1758bp, designated ibpB. The predicted amino acid sequences of these two genes demonstrate similarity to virulence exoproteins and their transporter proteins that comprise a two-partner secretion pathway in various Gram-negative bacteria. Motifs associated with binding to mammalian cells were also identified within the sequence. Competitive inhibition studies implicated a putative heparin-binding domain in adherence to bovine endothelial cells. Expression plasmids for glutathione S-transferase (GST)-fused recombinant fragments covered amino acid residues 972-3201. IgG2 Fc binding studies identified fragment 972-1515 (GST-IbpA3) as an Fc binding peptide. This peptide and GST-IbpA5 (aa 2071-2730) reacted strongly with convalescent phase serum. In a small preliminary study, calves immunized with the purified GST-IbpA3 peptide were protected against an intrabronchial H. somnus challenge.
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Affiliation(s)
- Yuichi Tagawa
- Department of Pathology, University of California, San Diego Medical Center, 200 West Arbor Drive, San Diego, CA 92103-8416, USA.
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8
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Pérez-Caballero D, García-Laorden I, Cortés G, Wessels MR, de Córdoba SR, Albertí S. Interaction between Complement Regulators andStreptococcus pyogenes: Binding of C4b-Binding Protein and Factor H/Factor H-Like Protein 1 to M18 Strains Involves Two Different Cell Surface Molecules. THE JOURNAL OF IMMUNOLOGY 2004; 173:6899-904. [PMID: 15557185 DOI: 10.4049/jimmunol.173.11.6899] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Streptococcus pyogenes, or group A Streptococcus, is one of the most frequent causes of pharyngitis and skin infections in humans. Many virulence mechanisms have been suggested to be involved in the infectious process. Among them is the binding to the bacterial cell surface of the complement regulatory proteins factor H, factor H-like protein 1 (FHL-1), and C4b-binding protein. Previous studies indicate that binding of these three regulators to the streptococcal cell involves the M protein encoded by the emm gene. M-type 18 strains are prevalent among clinical isolates and have been shown to interact with all three complement regulators simultaneously. Using isogenic strains lacking expression of the Emm18 or the Enn18 proteins, we demonstrate in this study that, in contradistinction to previously described S. pyogenes strains, M18 strains bind the complement regulators factor H, FHL-1, and C4b-binding protein through two distinct cell surface proteins. Factor H and FHL-1 bind to the Emm18 protein, while C4BP binds to the Enn18 protein. We propose that expression of two distinct surface structures that bind complement regulatory proteins represents a unique adaptation of M18 strains that enhances their resistance to opsonization by human plasma and increases survival of this particular S. pyogenes strain in the human host. These new findings illustrate that S. pyogenes has evolved diverse mechanisms for recruitment of complement regulatory proteins to the bacterial surface to evade immune clearance in the human host.
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Affiliation(s)
- David Pérez-Caballero
- Departamento de Inmunología, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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Meehan M, Lynagh Y, Woods C, Owen P. The fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi additionally binds IgG and contributes to virulence in a mouse model. MICROBIOLOGY (READING, ENGLAND) 2001; 147:3311-22. [PMID: 11739763 DOI: 10.1099/00221287-147-12-3311] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The major cell-wall-associated protein of the equine pathogen Streptococcus equi subsp. equi is an M-like fibrinogen-binding protein (FgBP) which binds equine fibrinogen (Fg) avidly, through residues located at the extreme N-terminus of the molecule. In this study, it is shown that FgBP additionally binds equine IgG-Fc. When tested against polyclonal IgG from ten other animal species, it was found that FgBP binds human, rabbit, pig and cat IgG, but does not bind mouse, rat, goat, sheep, cow or chicken IgG. Through the use of a panel of recombinant FgBP truncates containing defined deletions of sequence, it was shown that residues in the central regions of FgBP are important in IgG binding. An fbp knockout mutant which does not express FgBP on the cell surface was also constructed. Mutant cells failed to autoaggregate, bound no detectable equine Fg or IgG-Fc, were rapidly killed in horse blood, and showed greatly decreased virulence in a mouse model. Results suggest that FgBP is the major surface structure responsible for binding either Fg or IgG, that the molecule has pronounced antiphagocytic properties, and that it is a likely factor contributing to the virulence of wild-type S. equi subsp. equi.
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Affiliation(s)
- M Meehan
- Department of Microbiology, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
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Bessen DE, Izzo MW, McCabe EJ, Sotir CM. Two-domain motif for IgG-binding activity by group A streptococcal emm gene products. Gene 1997; 196:75-82. [PMID: 9322743 DOI: 10.1016/s0378-1119(97)00201-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A biological role for the non-immune binding of human IgG by group A streptococci is evidenced by its strong association with a subpopulation of strains giving rise to tissue-specific infection. IgG-binding activity lies within many of the M and M-like surface proteins (encoded by emm genes), and several structurally distinct IgG-binding sites are known to exist. In this report, two adjacent IgG-binding domains, differing in their specificity for human IgG subclasses, are localized within the M-like protein, protein H. The putative coding regions for the two IgG-binding domains were mapped for 82 epidemiologically unrelated strains. Both coding regions are associated with phylogenetically distant emm genes, supporting a role for horizontal transfer and intergenomic recombination in the evolution of emm genes. In most instances, the two coding regions are tightly linked, suggesting that there exist strong selective pressures to maintain a two-domain binding motif. Both coding regions are found among all strains bearing emm gene markers associated with impetigo lesions as the principal tissue reservoir, but are absent from most strains that exhibit markers for a predominant nasopharyngeal reservoir. The data support the hypothesis that the pathogenic potential of an isolate is dictated, at least in part, by its unique array of multifunctional emm gene products.
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Affiliation(s)
- D E Bessen
- Yale University School of Medicine, Department of Epidemiology and Public Health (Microbiology Section), New Haven, CT 06520, USA.
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11
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Tsivitse M, Boyle MD. Evidence for independent binding domains within a group A streptococcal type IIo IgG-binding protein. Can J Microbiol 1996; 42:1172-5. [PMID: 8941990 DOI: 10.1139/m96-149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The gene for a type IIo IgG-binding protein has previously been cloned and sequenced. The approximately 60,000 M(r) recombinant gene product binds all four human IgG subclasses and fibrinogen. Treatment of this recombinant protein with CNBr results in generation of a series of fragments. One fragment, an approximately 32,000 M(r) polypeptide, binds IgG1, IgG2, and IgG4 but neither IgG3 nor fibrinogen. N-terminal amino sequencing of this fragment indicated that this was an internal fragment of the protein starting at amino acid 186 of the mature protein. These findings provide evidence for two distinct domains for binding IgG1, IgG2, and IgG4 and binding IgG3 within a single bacterial IgG-binding protein.
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Affiliation(s)
- M Tsivitse
- Department of Microbiology, Medical College of Ohio 43699-0008, USA
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