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DebRoy S, Shropshire WC, Vega L, Tran C, Horstmann N, Mukherjee P, Selvaraj-Anand S, Tran TT, Bremer J, Gohel M, Arias CA, Flores AR, Shelburne SA. Identification of distinct impacts of CovS inactivation on the transcriptome of acapsular group A streptococci. mSystems 2023; 8:e0022723. [PMID: 37358280 PMCID: PMC10470059 DOI: 10.1128/msystems.00227-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/11/2023] [Indexed: 06/27/2023] Open
Abstract
Group A streptococcal (GAS) strains causing severe, invasive infections often have mutations in the control of virulence two-component regulatory system (CovRS) which represses capsule production, and high-level capsule production is considered critical to the GAS hypervirulent phenotype. Additionally, based on studies in emm1 GAS, hyperencapsulation is thought to limit transmission of CovRS-mutated strains by reducing GAS adherence to mucosal surfaces. It has recently been identified that about 30% of invasive GAS strains lacks capsule, but there are limited data regarding the impact of CovS inactivation in such acapsular strains. Using publicly available complete genomes (n = 2,455) of invasive GAS strains, we identified similar rates of CovRS inactivation and limited evidence for transmission of CovRS-mutated isolates for both encapsulated and acapsular emm types. Relative to encapsulated GAS, CovS transcriptomes of the prevalent acapsular emm types emm28, emm87, and emm89 revealed unique impacts such as increased transcript levels of genes in the emm/mga region along with decreased transcript levels of pilus operon-encoding genes and the streptokinase-encoding gene ska. CovS inactivation in emm87 and emm89 strains, but not emm28, increased GAS survival in human blood. Moreover, CovS inactivation in acapsular GAS reduced adherence to host epithelial cells. These data suggest that the hypervirulence induced by CovS inactivation in acapsular GAS follows distinct pathways from the better studied encapsulated strains and that factors other than hyperencapsulation may account for the lack of transmission of CovRS-mutated strains. IMPORTANCE Devastating infections due to group A streptococci (GAS) tend to occur sporadically and are often caused by strains that contain mutations in the control of virulence regulatory system (CovRS). In well-studied emm1 GAS, the increased production of capsule induced by CovRS mutation is considered key to both hypervirulence and limited transmissibility by interfering with proteins that mediate attachment to eukaryotic cells. Herein, we show that the rates of covRS mutations and genetic clustering of CovRS-mutated isolates are independent of capsule status. Moreover, we found that CovS inactivation in multiple acapsular GAS emm types results in dramatically altered transcript levels of a diverse array of cell-surface protein-encoding genes and a unique transcriptome relative to encapsulated GAS. These data provide new insights into how a major human pathogen achieves hypervirulence and indicate that factors other than hyperencapsulation likely account for the sporadic nature of the severe GAS disease.
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Affiliation(s)
- Sruti DebRoy
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - William C. Shropshire
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Luis Vega
- Division of Infectious Diseases and Department of Pediatrics, McGovern Medical School at UTHealth Houston and Children’s Memorial Hermann Hospital, Houston, Texas, USA
| | - Chau Tran
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Nicola Horstmann
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Piyali Mukherjee
- Division of Infectious Diseases and Department of Pediatrics, McGovern Medical School at UTHealth Houston and Children’s Memorial Hermann Hospital, Houston, Texas, USA
| | | | - Truc T. Tran
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Jordan Bremer
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Marc Gohel
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Cesar A. Arias
- Center for Infectious Diseases, Houston Methodist Research Institute, Houston, Texas, USA
- Division of Infectious Diseases, Department of Medicine, Houston Methodist Hospital, Houston, Texas, USA
| | - Anthony R. Flores
- Division of Infectious Diseases and Department of Pediatrics, McGovern Medical School at UTHealth Houston and Children’s Memorial Hermann Hospital, Houston, Texas, USA
| | - Samuel A. Shelburne
- Department of Infectious Diseases Infection Control and Employee Health, University of Texas MD Anderson Cancer Center, Houston, Texas, USA
- Department of Genomic Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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2
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Sudol ASL, Butler J, Ivory DP, Tews I, Crispin M. Extensive substrate recognition by the streptococcal antibody-degrading enzymes IdeS and EndoS. Nat Commun 2022; 13:7801. [PMID: 36528711 PMCID: PMC9759587 DOI: 10.1038/s41467-022-35340-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 11/25/2022] [Indexed: 12/23/2022] Open
Abstract
Enzymatic cleavage of IgG antibodies is a common strategy used by pathogenic bacteria to ablate immune effector function. The Streptococcus pyogenes bacterium secretes the protease IdeS and the glycosidase EndoS, which specifically catalyse cleavage and deglycosylation of human IgG, respectively. IdeS has received clinical approval for kidney transplantation in hypersensitised individuals, while EndoS has found application in engineering antibody glycosylation. We present crystal structures of both enzymes in complex with their IgG1 Fc substrate, which was achieved using Fc engineering to disfavour preferential Fc crystallisation. The IdeS protease displays extensive Fc recognition and encases the antibody hinge. Conversely, the glycan hydrolase domain in EndoS traps the Fc glycan in a "flipped-out" conformation, while additional recognition of the Fc peptide is driven by the so-called carbohydrate binding module. In this work, we reveal the molecular basis of antibody recognition by bacterial enzymes, providing a template for the development of next-generation enzymes.
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Affiliation(s)
- Abigail S. L. Sudol
- grid.5491.90000 0004 1936 9297School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ UK
| | - John Butler
- grid.5491.90000 0004 1936 9297School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ UK
| | - Dylan P. Ivory
- grid.5491.90000 0004 1936 9297School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ UK
| | - Ivo Tews
- grid.5491.90000 0004 1936 9297School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ UK
| | - Max Crispin
- grid.5491.90000 0004 1936 9297School of Biological Sciences, University of Southampton, Southampton, SO17 1BJ UK
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3
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Wang Z, Gu J, Xiao K, Zhu W, Lin Y, Wen S, He Q, Xu X, Cai X. Glaesserella parasuis autotransporters EspP1 and EspP2 are novel IgA-specific proteases. Front Microbiol 2022; 13:1041774. [PMID: 36590439 PMCID: PMC9797811 DOI: 10.3389/fmicb.2022.1041774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022] Open
Abstract
Background Glaesserella parasuis causes Glässer's disease, which is associated with severe polyarthritis, fibrinous polyserositis and meningitis, and leads to significant economic losses to the swine industry worldwide. IgA is one of the most important humoral immune factors present on mucosal surfaces, and it plays a crucial role in neutralizing and removing pathogens. G. parasuis is able to colonize the mucosal membrane of respiratory tract without being eliminated. Nevertheless, the immune evasion mechanism of G. parasuis in thwarting IgA remains unclear. Aims The object of this study is to characterize the IgA degradation activity of Mac-1-containing autotransporter EspP1 and EspP2 from G. parasuis. Methods The swine IgA was purified and incubated with EspP1 and EspP2 respectively. Western blotting was used to detect the cleavage of swine IgA. Generation of EspP1 and EspP2 mutant protein were used to explore the putative active sites of EspPs. LC-MS/MS based N/C-terminal sequencing was performed to measure the cleavage sites in swine IgA. Result Our results show that G. parasuis EspP1 and EspP2 cleave swine IgA in a dose- and time- dependent manner. G. parasuis lose the IgA protease activity after simultaneously delete espP1 and espP2 indicating that EspP1 and EspP2 are the only two IgA proteases in G. parasuis. The IgA protease activity of EspP1 and EspP2 is affected by the putative active sites which contain Cys47, His172 and Asp194/195. Swine IgA is cleaved within Cα1 and Cα3 domains upon incubation with EspPs. Moreover, EspPs can degrade neither IgG nor IgM while G. parasuis possess the ability to degrade IgM unexpectedly. It suggests that G. parasuis can secrete other proteases to cleave IgM which have never been reported. Conclusion We report for the first time that both EspP1 and EspP2 are novel IgA-specific proteases and cleave swine IgA within the Cα1 and Cα3 domains. These findings provide a theoretical basis for the EspPs-induced immune evasion.
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Affiliation(s)
- Zhichao Wang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Jiayun Gu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Kunxue Xiao
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Wenlong Zhu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Yan Lin
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Siting Wen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Qigai He
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Xiaojuan Xu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China
| | - Xuwang Cai
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China,Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China,*Correspondence: Xuwang Cai,
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4
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Kant S, Pancholi V. Novel Tyrosine Kinase-Mediated Phosphorylation With Dual Specificity Plays a Key Role in the Modulation of Streptococcus pyogenes Physiology and Virulence. Front Microbiol 2021; 12:689246. [PMID: 34950110 PMCID: PMC8689070 DOI: 10.3389/fmicb.2021.689246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/25/2021] [Indexed: 11/15/2022] Open
Abstract
Streptococcus pyogenes (Group A Streptococcus, GAS) genomes do not contain a gene encoding a typical bacterial-type tyrosine kinase (BY-kinase) but contain an orphan gene-encoding protein Tyr-phosphatase (SP-PTP). Hence, the importance of Tyr-phosphorylation is underappreciated and not recognized for its role in GAS pathophysiology and pathogenesis. The fact that SP-PTP dephosphorylates Abl-tyrosine kinase-phosphorylated myelin basic protein (MBP), and SP-STK (S. pyogenes Ser/Thr kinase) also autophosphorylates its Tyr101-residue prompted us to identify a putative tyrosine kinase and Tyr-phosphorylation in GAS. Upon a genome-wide search of kinases possessing a classical Walker motif, we identified a non-canonical tyrosine kinase M5005_Spy_1476, a ∼17 kDa protein (153 aa) (SP-TyK). The purified recombinant SP-TyK autophosphorylated in the presence of ATP. In vitro and in vivo phosphoproteomic analyses revealed two key phosphorylated tyrosine residues located within the catalytic domain of SP-TyK. An isogenic mutant lacking SP-TyK derived from the M1T1 strain showed a retarded growth pattern. It displayed defective cell division and long chains with multiple parallel septa, often resulting in aggregates. Transcriptomic analysis of the mutant revealed 287 differentially expressed genes responsible for GAS pathophysiology and pathogenesis. SP-TyK also phosphorylated GAS CovR, WalR, SP-STP, and SDH/GAPDH proteins with dual specificity targeting their Tyr/Ser/Thr residues as revealed by biochemical and mass-spectrometric-based phosphoproteomic analyses. SP-TyK-phosphorylated CovR bound to PcovR efficiently. The mutant displayed sustained release of IL-6 compared to TNF-α during co-culturing with A549 lung cell lines, attenuation in mice sepsis model, and significantly reduced ability to adhere to and invade A549 lung cells and form biofilms on abiotic surfaces. SP-TyK, thus, plays a critical role in fine-tuning the regulation of key cellular functions essential for GAS pathophysiology and pathogenesis through post-translational modifications and hence, may serve as a promising target for future therapeutic developments.
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5
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Nicholson TL, Waack U, Anderson TK, Bayles DO, Zaia SR, Goertz I, Eppinger M, Hau SJ, Brockmeier SL, Shore SM. Comparative Virulence and Genomic Analysis of Streptococcus suis Isolates. Front Microbiol 2021; 11:620843. [PMID: 33574803 PMCID: PMC7870872 DOI: 10.3389/fmicb.2020.620843] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Streptococcus suis is a zoonotic bacterial swine pathogen causing substantial economic and health burdens to the pork industry. Mechanisms used by S. suis to colonize and cause disease remain unknown and vaccines and/or intervention strategies currently do not exist. Studies addressing virulence mechanisms used by S. suis have been complicated because different isolates can cause a spectrum of disease outcomes ranging from lethal systemic disease to asymptomatic carriage. The objectives of this study were to evaluate the virulence capacity of nine United States S. suis isolates following intranasal challenge in swine and then perform comparative genomic analyses to identify genomic attributes associated with swine-virulent phenotypes. No correlation was found between the capacity to cause disease in swine and the functional characteristics of genome size, serotype, sequence type (ST), or in vitro virulence-associated phenotypes. A search for orthologs found in highly virulent isolates and not found in non-virulent isolates revealed numerous predicted protein coding sequences specific to each category. While none of these predicted protein coding sequences have been previously characterized as potential virulence factors, this analysis does provide a reliable one-to-one assignment of specific genes of interest that could prove useful in future allelic replacement and/or functional genomic studies. Collectively, this report provides a framework for future allelic replacement and/or functional genomic studies investigating genetic characteristics underlying the spectrum of disease outcomes caused by S. suis isolates.
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Affiliation(s)
- Tracy L Nicholson
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Ursula Waack
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States.,Oak Ridge Institute for Science and Education, United States Department of Energy, Oak Ridge, TN, United States
| | - Tavis K Anderson
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Darrell O Bayles
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Sam R Zaia
- South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States.,Department of Biology, University of Texas at San Antonio, San Antonio, TX, United States
| | - Isaiah Goertz
- South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States.,Department of Biology, University of Texas at San Antonio, San Antonio, TX, United States
| | - Mark Eppinger
- South Texas Center for Emerging Infectious Diseases, The University of Texas at San Antonio, San Antonio, TX, United States.,Department of Biology, University of Texas at San Antonio, San Antonio, TX, United States
| | - Samantha J Hau
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States.,Oak Ridge Institute for Science and Education, United States Department of Energy, Oak Ridge, TN, United States
| | - Susan L Brockmeier
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
| | - Sarah M Shore
- National Animal Disease Center, Agricultural Research Service, United States Department of Agriculture, Ames, IA, United States
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6
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Jie P, Zhe M, Chengwei H, Huixing L, Hui Z, Chengping L, Hongjie F. Virulent and Vaccine Strains of Streptococcus equi ssp. zooepidemicus Have Different Influences on Phagocytosis and Cytokine Secretion of Macrophages. J Proteome Res 2016; 16:77-86. [PMID: 27726373 DOI: 10.1021/acs.jproteome.6b00571] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Swine streptococcosis is a significant threat to the Chinese pig industry, and Streptococcus equi ssp. zooepidemicus (SEZ) is one of the major pathogens. SEZ ATCC35246 is a classical virulent strain, while SEZ ST171 is a Chinese attenuated vaccine strain. In this study, we employed stable isotope labeling by amino acids in cell culture and liquid chromatography-mass spectrometry (LC-MS) to determine the differential response of macrophages to infection by these two strains. Eighty-seven upregulated proteins and 135 downregulated proteins were identified. The proteomic results were verified by real-time polymerase chain reaction for 10 chosen genes and Western blotting for three proteins. All differentially abundant proteins were analyzed for their Gene Ontology and Kyoto Encyclopedia of Genes and Genomes annotations. Certain downregulated proteins were associated with immunity functions, and the upregulated proteins were related to cytomembrane and cytoskeleton regulation. The phagocytosis rate and cytokine genes transcription in Raw264.7 cells during SEZ ATCC35246 and ST171 infection were detected to confirm the bioinformatics results. These results showed that different effects on macrophage phagocytosis and cytokine expression might explain the different phenotypes of SEZ ATCC35246 and ST171 infection. This research provided clues to the mechanisms of host immunity responses to SEZ ST171and SEZ ATCC35246, which could identify potential therapy and vaccine development targets.
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Affiliation(s)
- Peng Jie
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, China
| | - Ma Zhe
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Hua Chengwei
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, China
| | - Lin Huixing
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
| | - Zhang Hui
- China Animal Health and Epidemiology Center, Qingdao 266032, China
| | - Lu Chengping
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, China
| | - Fan Hongjie
- College of Veterinary Medicine, Nanjing Agricultural University , Nanjing 210095, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China
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7
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Persson H, Söderberg JJ, Vindebro R, Johansson BP, von Pawel-Rammingen U. Proteolytic processing of the streptococcal IgG endopeptidase IdeS modulates the functional properties of the enzyme and results in reduced immunorecognition. Mol Immunol 2015; 68:176-84. [DOI: 10.1016/j.molimm.2015.07.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 07/10/2015] [Accepted: 07/13/2015] [Indexed: 01/01/2023]
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8
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IgG protease Mac/IdeS is not essential for phagocyte resistance or mouse virulence of M1T1 group A Streptococcus. mBio 2013; 4:mBio.00499-13. [PMID: 23900173 PMCID: PMC3735186 DOI: 10.1128/mbio.00499-13] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Mac/IdeS protein of group A Streptococcus (GAS) is a secreted cysteine protease with cleavage specificity for IgG and is highly expressed in the GAS serotype M1T1 clone, which is the serotype most frequently isolated from patients with life-threatening invasive infections. While studies of Mac/IdeS with recombinant protein have shown that the protein can potentially prevent opsonophagocytosis of GAS by neutrophils, the role of the protein in immune evasion as physiologically produced by the living organism has not been studied. Here we examined the contribution of Mac/IdeS to invasive GAS disease by generating a mutant lacking Mac/IdeS in the hyperinvasive M1T1 background. While Mac/IdeS was highly expressed and proteolytically active in the hyperinvasive strain, elimination of the bacterial protease did not significantly influence GAS phagocytic uptake, oxidative-burst induction, cathelicidin sensitivity, resistance to neutrophil or macrophage killing, or pathogenicity in pre- or postimmune mouse infectious challenges. We conclude that in the highly virulent M1T1 background, Mac/IdeS is not essential for either phagocyte resistance or virulence. Given the conservation of Mac/IdeS and homologues across GAS strains, it is possible that Mac/IdeS serves another important function in GAS ecology or contributes to virulence in other strain backgrounds. Group A Streptococcus (GAS) causes human infections ranging from strep throat to life-threatening conditions such as flesh-eating disease and toxic shock syndrome. Common disease-associated clones of GAS can cause both mild and severe infections because of a characteristic mutation and subsequent change in the expression of several genes that develops under host immune selection. One of these genes encodes Mac/IdeS, a protease that has been shown to cleave antibodies important to the immune defense system. In this study, we found that while Mac/IdeS is highly expressed in hypervirulent GAS, it does not significantly contribute to the ability of the bacteria to survive white blood cell killing or produce invasive infection in the mouse. These data underscore the importance of correlating studies on virulence factor function with physiologic expression levels and the complexity of streptococcal pathogenesis and contribute to our overall understanding of how GAS causes disease.
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9
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Vindebro R, Spoerry C, von Pawel-Rammingen U. Rapid IgG heavy chain cleavage by the streptococcal IgG endopeptidase IdeS is mediated by IdeS monomers and is not due to enzyme dimerization. FEBS Lett 2013; 587:1818-22. [PMID: 23665032 DOI: 10.1016/j.febslet.2013.04.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 04/19/2013] [Accepted: 04/23/2013] [Indexed: 10/26/2022]
Abstract
Streptococcus pyogenes employs an IgG specific endopeptidase, IdeS, to counteract the effector functions of specific IgG. The physiological significant step in disarming specific IgG is the cleavage of one IgG heavy chain. So far, characterizations of IdeS enzymatic activity have employed techniques that failed to differentiate between the first and the second cleavage step. The present data demonstrate that IdeS is active as a monomer and that IdeS activity follows classical Michaelis-Menten kinetics arguing against the previously proposed formation of a functional IdeS dimer. Our results show that IdeS inactivates IgG 100-fold faster than previously reported.
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Affiliation(s)
- Reine Vindebro
- Department of Molecular Biology and Umeå Centre for Microbial Research, Umeå University, 90187 Umeå, Sweden
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10
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Berggren K, Vindebro R, Bergström C, Spoerry C, Persson H, Fex T, Kihlberg J, von Pawel-Rammingen U, Luthman K. 3-aminopiperidine-based peptide analogues as the first selective noncovalent inhibitors of the bacterial cysteine protease IdeS. J Med Chem 2012; 55:2549-60. [PMID: 22369147 PMCID: PMC3310199 DOI: 10.1021/jm201517a] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A series of eight peptides corresponding to the amino acid sequence of the hinge region of IgG and 17 newly synthesized peptide analogues containing a piperidine moiety as a replacement of a glycine residue were tested as potential inhibitors of the bacterial IgG degrading enzyme of Streptococcus pyogenes , IdeS. None of the peptides showed any inhibitory activity of IdeS, but several piperidine-based analogues were identified as inhibitors. Two different analysis methods were used: an SDS-PAGE based assay to detect IgG cleavage products and a surface plasmon resonance spectroscopy based assay to quantify the degree of inhibition. To investigate the selectivity of the inhibitors for IdeS, all compounds were screened against two other related cysteine proteases (SpeB and papain). The selectivity results show that larger analogues that are active inhibitors of IdeS are even more potent as inhibitors of papain, whereas smaller analogues that are active inhibitors of IdeS inhibit neither SpeB nor papain. Two compounds were identified that exhibit high selectivity against IdeS and will be used for further studies.
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Affiliation(s)
- Kristina Berggren
- Department of Chemistry, Medicinal Chemistry, University of Gothenburg, SE-412 96 Göteborg, Sweden
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11
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von Pawel-Rammingen U. Streptococcal IdeS and its impact on immune response and inflammation. J Innate Immun 2012; 4:132-40. [PMID: 22248585 DOI: 10.1159/000332940] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 09/01/2011] [Indexed: 11/19/2022] Open
Abstract
Survival of the important bacterial pathogen Streptococcus pyogenes relies on its ability to circumvent the antimicrobial actions of innate and specific immune responses and to modulate the inflammatory responses induced during the course of an infection. Inflammatory processes play key roles during streptococcal pathogenesis and streptococcal infections are accompanied by an intense inflammatory state. As an exclusively human pathogen, S. pyogenes has adapted to the various countermeasures employed by its host to fight bacterial infections, in particular to interfere with the effector functions of immunoglobulin G (IgG). For this purpose, S. pyogenes has evolved an IgG-specific endopeptidase, IdeS, which is highly specific for the lower hinge region of IgG. This review summarizes the current knowledge about this intriguing enzyme as well as its role in inflammation and in the attenuation of human immune responses towards streptococcal infection.
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12
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Reiss K, Kirchner E, Gijzen M, Zocher G, Löffelhardt B, Nürnberger T, Stehle T, Brunner F. Structural and phylogenetic analyses of the GP42 transglutaminase from Phytophthora sojae reveal an evolutionary relationship between oomycetes and marine Vibrio bacteria. J Biol Chem 2011; 286:42585-42593. [PMID: 21994936 DOI: 10.1074/jbc.m111.290544] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Transglutaminases (TGases) are ubiquitous enzymes that catalyze selective cross-linking between protein-bound glutamine and lysine residues; the resulting isopeptide bond confers high resistance to proteolysis. Phytophthora sojae, a pathogen of soybean, secretes a Ca(2+)-dependent TGase (GP42) that is activating defense responses in both host and non-host plants. A GP42 fragment of 13 amino acids, termed Pep-13, was shown to be absolutely indispensable for both TGase and elicitor activity. GP42 does not share significant primary sequence similarity with known TGases from mammals or bacteria. This suggests that GP42 has evolved novel structural and catalytic features to support enzymatic activity. We have solved the crystal structure of the catalytically inactive point mutant GP42 (C290S) at 2.95 Å resolution and identified residues involved in catalysis by mutational analysis. The protein comprises three domains that assemble into an elongated structure. Although GP42 has no structural homolog, its core region displays significant similarity to the catalytic core of the Mac-1 cysteine protease from Group A Streptococcus, a member of the papain-like superfamily of cysteine proteases. Proteins that are taxonomically related to GP42 are only present in plant pathogenic oomycetes belonging to the order of the Peronosporales (e.g. Phytophthora, Hyaloperonospora, and Pythium spp.) and in marine Vibrio bacteria. This suggests that a lateral gene transfer event may have occurred between bacteria and oomycetes. Our results offer a basis to design and use highly specific inhibitors of the GP42-like TGase family that may impair the growth of important oomycete and bacterial pathogens.
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Affiliation(s)
- Kerstin Reiss
- Interfakultäres Institut für Biochemie, Universität Tübingen, 72076 Tübingen, Germany
| | - Eva Kirchner
- Interfakultäres Institut für Biochemie, Universität Tübingen, 72076 Tübingen, Germany
| | - Mark Gijzen
- Agri-Food Canada, London, Ontario N5V 4T3, Canada
| | - Georg Zocher
- Interfakultäres Institut für Biochemie, Universität Tübingen, 72076 Tübingen, Germany
| | - Birgit Löffelhardt
- Zentrum für Molekularbiologie der Pflanzen, Universität Tübingen, 72076 Tübingen, Germany
| | - Thorsten Nürnberger
- Zentrum für Molekularbiologie der Pflanzen, Universität Tübingen, 72076 Tübingen, Germany
| | - Thilo Stehle
- Interfakultäres Institut für Biochemie, Universität Tübingen, 72076 Tübingen, Germany; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
| | - Frédéric Brunner
- Zentrum für Molekularbiologie der Pflanzen, Universität Tübingen, 72076 Tübingen, Germany.
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13
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Ishihara K, Wawrzonek K, Shaw LN, Inagaki S, Miyamoto M, Potempa J. Dentipain, a Streptococcus pyogenes IdeS protease homolog, is a novel virulence factor of Treponema denticola. Biol Chem 2011; 391:1047-55. [PMID: 20635859 DOI: 10.1515/bc.2010.113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Treponema denticola is a major pathogen of chronic periodontitis. Analysis of the T. denticola genome revealed a gene orthologous with a cysteine protease-encoding gene from Streptococcus pyogenes (IdeS). IdeS interferes with IgG-dependent opsonophagocytosis by specific cleavage of IgG molecules. Analysis of this gene (termed ideT) revealed it to encode a two-domain protein whose N-terminus is composed of tandem immunoglobulin-like domains followed by a C-terminal IdeS-like protease domain. In this study we show that during secretion the IdeT protein is processed into an N-terminal fragment which remains associated with the cell, and a C-terminal part released into the medium. Although the secreted domain of IdeT, termed dentipain, shows only 25% identity to the IdeS protease, the putative catalytic cysteine and histidine residues are strongly conserved. Recombinant dentipain cleaves the insulin β-chain, an activity which is inhibited by E-64, a diagnostic inhibitor of cysteine proteases. Apart from insulin no cleavage of other protein substrates was detected, suggesting that dentipain has oligopeptidase activity. A mutant strain was constructed expressing a modified IdeT variant, the dentipain domain of which was deleted. This strain was found to be significantly reduced in its abscess-forming activity compared with the parental strain in a murine abscess model, suggesting that dentipain contributes to the virulence of T. denticola.
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Affiliation(s)
- Kazuyuki Ishihara
- Oral Health Science Center, Tokyo Dental College, Chiba 261-8502, Japan.
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14
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Radaev S, Agniswamy J, Sun PD. A case of structure determination using pseudosymmetry. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2009; 65:1334-40. [PMID: 19966420 PMCID: PMC2789005 DOI: 10.1107/s0907444909039912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 09/30/2009] [Indexed: 11/10/2022]
Abstract
Here, a case is presented of an unusual structure determination which was facilitated by the use of pseudosymmetry. Group A streptococcus uses cysteine protease Mac-1 (also known as IdeS) to evade the host immune system. Native Mac-1 was crystallized in the orthorhombic space group P2(1)2(1)2. Surprisingly, crystals of the inactive C94A mutant of Mac-1 displayed monoclinic symmetry with space group P2(1), despite the use of native orthorhombic Mac-1 microcrystals for seeding. Attempts to solve the structure of the C94A mutant by MAD phasing in the monoclinic space group did not produce an interpretable map. The native Patterson map of the C94A mutant showed two strong peaks along the (1 0 1) diagonal, indicating possible translational pseudosymmetry in space group P2(1). Interestingly, one-third of the monoclinic reflections obeyed pseudo-orthorhombic P2(1)2(1)2 symmetry similar to that of the wild-type crystals and could be indexed and processed in this space group. The pseudo-orthorhombic and monoclinic unit cells were related by the following vector operations: a(m) = b(o) - c(o), b(m) = a(o) and c(m) = -2c(o) - b(o). The pseudo-orthorhombic subset of data produced good SAD phases, leading to structure determination with one monomer in the asymmetric unit. Subsequently, the structure of the Mac-1 mutant in the monoclinic form was determined by molecular replacement, which showed six molecules forming three translationally related dimers aligned along the (1 0 1) diagonal. Knowing the geometric relationship between the pseudo-orthorhombic and the monoclinic unit cells, all six molecules can be generated in the monoclinic unit cell directly without the use of molecular replacement. The current case provides a successful example of the use of pseudosymmetry as a powerful phase-averaging method for structure determination by anomalous diffraction techniques. In particular, a structure can be solved in a higher pseudosymmetry subcell in which an NCS operator becomes a crystallographic operator. The geometrical relationships between the subcell and parental cell can be used to generate a complete molecular representation of the parental asymmetric unit for refinement.
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Affiliation(s)
- Sergei Radaev
- Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, Maryland 20852, USA
| | - Johnson Agniswamy
- Department of Biology, Georgia State University, PO Box 4010, Atlanta, GA 30302, USA
| | - Peter D. Sun
- Structural Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 12441 Parklawn Drive, Rockville, Maryland 20852, USA
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15
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MacKenzie DA, Tailford LE, Hemmings AM, Juge N. Crystal structure of a mucus-binding protein repeat reveals an unexpected functional immunoglobulin binding activity. J Biol Chem 2009; 284:32444-53. [PMID: 19758995 DOI: 10.1074/jbc.m109.040907] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Lactobacillus reuteri mucus-binding protein (MUB) is a cell-surface protein that is involved in bacterial interaction with mucus and colonization of the digestive tract. The 353-kDa mature protein is representative of a broadly important class of adhesins that have remained relatively poorly characterized due to their large size and highly modular nature. MUB contains two different types of repeats (Mub1 and Mub2) present in six and eight copies, respectively, and shown to be responsible for the adherence to intestinal mucus. Here we report the 1.8-A resolution crystal structure of a type 2 Mub repeat (184 amino acids) comprising two structurally related domains resembling the functional repeat found in a family of immunoglobulin (Ig)-binding proteins. The N-terminal domain bears striking structural similarity to the repeat unit of Protein L (PpL) from Peptostreptococcus magnus, suggesting binding in a non-immune Fab-dependent manner. A distorted PpL-like fold is also seen in the C-terminal domain. As with PpL, Mub repeats were able to interact in vitro with a large repertoire of mammalian Igs, including secretory IgA. This hitherto undetected activity is consistent with the current model that antibody responses against commensal flora are of broad specificity and low affinity.
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Affiliation(s)
- Donald A MacKenzie
- Institute of Food Research, Colney Lane, Norwich NR4 7UA, United Kingdom
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16
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Hulting G, Flock M, Frykberg L, Lannergård J, Flock JI, Guss B. Two novel IgG endopeptidases ofStreptococcus equi. FEMS Microbiol Lett 2009; 298:44-50. [DOI: 10.1111/j.1574-6968.2009.01698.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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17
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Olsen JG, Dagil R, Niclasen LM, Sørensen OE, Kragelund BB. Structure of the mature Streptococcal cysteine protease exotoxin mSpeB in its active dimeric form. J Mol Biol 2009; 393:693-703. [PMID: 19712682 DOI: 10.1016/j.jmb.2009.08.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 08/13/2009] [Accepted: 08/19/2009] [Indexed: 11/29/2022]
Abstract
Invasive infections of Streptococcus pyogenes are dependent on the cysteine protease streptococcal pyrogenic exotoxin B. Previous structures of the enzyme have not disclosed the proper active-site configuration. Here, the crystal structure of the mature enzyme is presented to 1.55 A, disclosing a homodimer. A serine from one subunit inserts into the active site of the other to donate to the oxyanion hole and coordinates the ligand proximal to the active-site cysteine. Dimerization is unique to the mature form and is clearly a prerequisite for catalysis. The present structure supports a tripartite switch system that is triggered upon dimerization and substrate binding: (1) liberation of the active-site histidine from an inactive configuration, (2) relocation of residues blocking the substrate binding pockets and (3) repositioning of two active-site tryptophans to settle in the active configuration. Based on the present structure, the active site of clan CA cysteine proteases is expanded and a detailed mechanism of the deacylation mechanism is proposed. The results may have applications for the development of protease inhibitors specific to bacterial cysteine proteases.
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Affiliation(s)
- Johan G Olsen
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, Copenhagen, Denmark
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18
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Vincents B, Vindebro R, Abrahamson M, von Pawel-Rammingen U. The human protease inhibitor cystatin C is an activating cofactor for the streptococcal cysteine protease IdeS. ACTA ACUST UNITED AC 2008; 15:960-8. [PMID: 18804033 DOI: 10.1016/j.chembiol.2008.07.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 06/27/2008] [Accepted: 07/11/2008] [Indexed: 10/21/2022]
Abstract
Human cystatin C is considered the physiologically most important inhibitor of endogenous papain-like cysteine proteases. We present here an unexpected function of cystatin C. Instead of acting as an inhibitor, cystatin C acts as a facultative, endogenous cofactor for the papain-like IgG-cleaving enzyme IdeS of the human pathogen Streptococcus pyogenes. IdeS activity is not dependent on cystatin C, but is significantly enhanced in the presence of cystatin C. We report a protease inhibitor that accelerates the activity of its putative target protease and a unique example of how a host protease inhibitor is "hijacked" by a bacterial protease to increase its activity. This finding has important implications for the view on protease-inhibitor interactions, and is relevant to consider in the therapeutic use of protease inhibitors.
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Affiliation(s)
- Bjarne Vincents
- Department of Laboratory Medicine, Division of Clinical Chemistry and Pharmacology, Lund University, University Hospital, Lund, Sweden
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19
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Shen A, Bogyo M. Friend or foe? Turning a host defense protein into a pathogen's accomplice. ACTA ACUST UNITED AC 2008; 15:879-80. [PMID: 18804024 DOI: 10.1016/j.chembiol.2008.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Cystatins are cysteine protease inhibitors that are at the front-line of defense against pathogens that secrete proteases as virulence factors. In this issue, Vincents et al. (2008) reveal how the bacterial protease IdeS from Streptococcus pyogenes hijacks normal cystatin C function to convert it into a cofactor that enhances proteolytic destruction of host-defense antibodies.
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Affiliation(s)
- Aimee Shen
- Department of Pathology and Microbiology and Immunology, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5324, USA
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20
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The intrinsic immunoglobulin g endopeptidase activity of streptococcal Mac-2 proteins implies a unique role for the enzymatically impaired Mac-2 protein of M28 serotype strains. Infect Immun 2008; 76:2183-8. [PMID: 18332209 DOI: 10.1128/iai.01422-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
IdeS, a secreted cysteine protease of the important human pathogen Streptococcus pyogenes, interferes with phagocytic killing by specifically cleaving the heavy chain of immunoglobulin G (IgG). Two allelic variants of the enzyme have been described, the IgG-specific endopeptidase, IdeS (or Mac-1) and Mac-2, a protein with only weak IgG endopeptidase activity, which has been suggested to interfere with opsonophagocytosis by blocking Fcgamma receptors of phagocytic cells. However, despite the fact that Mac-2 proteins interact with Fcgamma receptors, no inhibition of reactive oxygen species (ROS) production, opsonophagocytosis, or streptococcal killing by Mac-2 has been reported. In the present study, Mac-2 proteins are shown to contain IgG endopeptidase activity indistinguishable from the enzymatic activity exhibited by IdeS/Mac-1 proteins. The earlier reported weak IgG endopeptidase activity appears to be unique to Mac-2 of M28 serotype strains (Mac-2(M28)) and is most likely due to the formation of a disulfide bond between the catalytic site cysteine and a cysteine residue in position 257 of Mac-2(M28). Furthermore, Mac-2 proteins are shown to inhibit ROS production ex vivo, independently of the IgG endopeptidase activity of the proteins. Inhibition of ROS generation per se, however, was not sufficient to mediate streptococcal survival in bactericidal assays. Thus, in contrast to earlier studies, implicating separate functions for IdeS and Mac-2 protein variants, the current study suggests that Mac-2 and IdeS are bifunctional proteins, combining Fcgamma receptor binding and IgG endopeptidase activity. This finding implies a unique role for Mac-2 proteins of the M28 serotype, since this serotype has evolved and retained a Mac-2 protein lacking IgG endopeptidase activity.
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21
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Hess JL, Porsch EA, Shertz CA, Boyle MDP. Immunoglobulin cleavage by the streptococcal cysteine protease IdeS can be detected using protein G capture and mass spectrometry. J Microbiol Methods 2007; 70:284-91. [PMID: 17543400 PMCID: PMC1986777 DOI: 10.1016/j.mimet.2007.04.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Revised: 04/03/2007] [Accepted: 04/26/2007] [Indexed: 11/29/2022]
Abstract
The immunoglobulin degrading enzyme of Streptococcus pyogenes, IdeS, is an unusual cysteine protease produced by group A streptococci for which the only known substrate is immunoglobulin G (IgG). To date, IdeS has not been found to cleave any of the known synthetic substrates that other cysteine proteases hydrolyse, thus making the development of an IdeS detection assay difficult. Furthermore, at high doses of substrate, product generation is inhibited potentially due to the need for a dimeric enzyme complex with IgG. In this study we have developed a mass spectral assay for IdeS activity based on the detection of an Mr approximately 25,300 Fc fragment that retains the ability to bind streptococcal protein G. Using this assay procedure, evidence for a multimeric enzyme-substrate complex was obtained as well as identifying isolated heavy chains as a non-substrate inhibitor of IdeS activity. Under appropriate experimental conditions the assay could be used to detect IdeS activity in bacterial culture media or in human plasma without a requirement for purified reactants. The availability of a rapid and sensitive assay for IdeS should facilitate the detailed biochemical characterization of this unusual bacterial cysteine protease.
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Affiliation(s)
- Jennifer L Hess
- Department of Biology, Juniata College, 1700 Moore St, Huntingdon, Pennsylvania 16652, USA
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22
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Ghumra A, Pleass RJ. Escherichia coli do not express Fc-receptors for human immunoglobulin G (IgG). Mol Immunol 2007; 44:2144-6. [PMID: 17070911 DOI: 10.1016/j.molimm.2006.09.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 09/14/2006] [Accepted: 09/18/2006] [Indexed: 10/24/2022]
Abstract
Gram-positive bacterial pathogens express immunoglobulin (Ig) binding proteins that perturb Fc-dependent functions such as the interaction with complement or phagocytic Fc-receptors. The possession of such molecules by gram-negative bacteria, including Escherichia coli (E. coli), has also been documented. In many such studies, the detection of Ig binding has relied on the use of polyclonal antibodies as detecting reagents. These are not ideal since such preparations may be contaminated with E. coli specific IgG, allowing for the potential misinterpretation of specific F(ab')(2) binding as non-specific Fc mediated binding. Here we use mono-specific recombinant antibodies to develop a novel assay for Ig binding non reliant on traditional polyclonal antibodies, allowing us to demonstrate the unequivocal absence of Fc binding proteins from E. coli.
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Affiliation(s)
- Ashfaq Ghumra
- Institute of Genetics, School of Biology, University of Nottingham NG7 2UH, UK
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23
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Rich RL, Myszka DG. Survey of the year 2006 commercial optical biosensor literature. J Mol Recognit 2007; 20:300-66. [DOI: 10.1002/jmr.862] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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