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Sleutel M, Zegeye ED, Llarena AK, Pradhan B, Fislage M, O'Sullivan K, Van Gerven N, Aspholm M, Remaut H. Helical ultrastructure of the L-ENA spore aggregation factor of a Bacillus paranthracis foodborne outbreak strain. Nat Commun 2024; 15:7514. [PMID: 39209852 PMCID: PMC11362473 DOI: 10.1038/s41467-024-51804-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 08/16/2024] [Indexed: 09/04/2024] Open
Abstract
In pathogenic Bacillota, spores can form an infectious particle and can take up a central role in the environmental persistence and dissemination of disease. A poorly understood aspect of spore-mediated infection is the fibrous structures or 'endospore appendages' (ENAs) that have been seen to decorate the spores of pathogenic Bacilli and Clostridia. Current methodological approaches are opening a window on these long enigmatic structures. Using cryoID, Alphafold modelling and genetic approaches we identify a sub-class of robust ENAs in a Bacillus paranthracis foodborne outbreak strain. We demonstrate that L-ENA are encoded by a rare three-gene cluster (ena3) that contains all components for the self-assembly of ladder-like protein nanofibers of stacked heptameric rings, their anchoring to the exosporium, and their termination in a trimeric 'ruffle' made of a complement C1Q-like BclA paralogue. The role of ENA fibers in spore-spore interaction and the distribution of L-ENA operon as mobile genetic elements in B. cereus s.l. strains suggest that L-ENA fibers may increase the survival, spread and virulence of these strains.
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Affiliation(s)
- Mike Sleutel
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium.
| | - Ephrem Debebe Zegeye
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Ann-Katrin Llarena
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Brajabandhu Pradhan
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium
| | - Marcus Fislage
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium
| | - Kristin O'Sullivan
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Nani Van Gerven
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium
| | - Marina Aspholm
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Han Remaut
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
- Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium.
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2
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Chattopadhyay D, Walker DR, Rich-New ST, Kearney JF, Turnbough, Jr. CL. Crystal structure and induced stability of trimeric BxpB: implications for the assembly of BxpB-BclA complexes in the exosporium of Bacillus anthracis. mBio 2023; 14:e0117223. [PMID: 37382447 PMCID: PMC10470788 DOI: 10.1128/mbio.01172-23] [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: 05/08/2023] [Accepted: 05/10/2023] [Indexed: 06/30/2023] Open
Abstract
The outermost exosporium layer of Bacillus anthracis spores, the causative agents of anthrax, is comprised of a basal layer and an external hair-like nap. The nap includes filaments composed of trimers of the collagen-like glycoprotein BclA. Essentially all BclA trimers are attached to the spore in a process in which part of the 38-residue amino-terminal domain (NTD) of BclA forms an extremely stable interaction with the basal layer protein BxpB. Evidence indicates that the BclA-BxpB interaction is direct and requires trimeric BxpB. To further investigate the nature of the BclA-BxpB interaction, we determined the crystal structure of BxpB. The structure was trimeric with each monomer consisting of 11 β strands with connecting loops. The structure did not include apparently disordered amino acids 1-19, which contain the only two cysteine residues of the 167-residue BxpB. The orientation of the structure reveals regions of BxpB that could be involved in interacting with the BclA NTD and with adjacent cysteine-rich proteins in the basal layer. Furthermore, the BxpB structure closely resembles that of the 134-residue carboxyl-terminal domain of BclA, which forms trimers that are highly resistant to heat and detergent. We demonstrated that BxpB trimers do not share this resistance. However, when BxpB trimers are mixed with a peptide containing residues 20-38 of BclA, they form a complex that is as stable as BclA-BxpB complexes extracted from spores. Together, our results provide new insights into the mechanism of BclA-BxpB attachment and incorporation into the exosporium. IMPORTANCE The B. anthracis exosporium plays major roles in spore survival and infectivity, but the complex mechanism of its assembly is poorly understood. Key steps in this process are the stable attachment of collagen-like BclA filaments to the major basal layer structural protein BxpB and the insertion of BxpB into an underlying basal layer scaffold. The goal of this study is to further elucidate these interactions thereby advancing our understanding of exosporium assembly, a process shared by many spore-forming bacteria including important human pathogens.
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Affiliation(s)
| | - Dionna R. Walker
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Shane T. Rich-New
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - John F. Kearney
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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3
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Mechanisms and Applications of Bacterial Sporulation and Germination in the Intestine. Int J Mol Sci 2022; 23:ijms23063405. [PMID: 35328823 PMCID: PMC8953710 DOI: 10.3390/ijms23063405] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/15/2022] [Accepted: 03/18/2022] [Indexed: 02/04/2023] Open
Abstract
Recent studies have suggested a major role for endospore forming bacteria within the gut microbiota, not only as pathogens but also as commensal and beneficial members contributing to gut homeostasis. In this review the sporulation processes, spore properties, and germination processes will be explained within the scope of the human gut. Within the gut, spore-forming bacteria are known to interact with the host’s immune system, both in vegetative cell and spore form. Together with the resistant nature of the spore, these characteristics offer potential for spores’ use as delivery vehicles for therapeutics. In the last part of the review, the therapeutic potential of spores as probiotics, vaccine vehicles, and drug delivery systems will be discussed.
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4
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Paredes-Sabja D, Cid-Rojas F, Pizarro-Guajardo M. Assembly of the exosporium layer in Clostridioides difficile spores. Curr Opin Microbiol 2022; 67:102137. [PMID: 35182899 DOI: 10.1016/j.mib.2022.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/14/2022] [Accepted: 01/20/2022] [Indexed: 02/07/2023]
Abstract
Clostridioides difficile is a Gram-positive, spore-forming obligate anaerobe and a major threat to the healthcare system world-wide. Because of its strict anaerobic requirements, the infectious and transmissible morphotype is the dormant spore. During infection, C. difficile produces spores that can persist in the host and are responsible for disease recurrence and transmission, especially between hospitalized patients. Although the C. difficile spore surface mediates critical interactions with host surfaces, this outermost layer, known as the exosporium, is poorly conserved when compared to members of the Bacillus genus. Notably, the exosporium has been shown to be important for the persistence of C. difficile in the host. In this review, the ultrastructural properties, composition, and morphogenesis of the exosporium will be discussed.
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Affiliation(s)
- Daniel Paredes-Sabja
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA; ANID - Millennium Science Initiative Program - Millennium Nucleus in the Biology of the Intestinal Microbiota, Santiago, Chile.
| | - Francisca Cid-Rojas
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA; ANID - Millennium Science Initiative Program - Millennium Nucleus in the Biology of the Intestinal Microbiota, Santiago, Chile
| | - Marjorie Pizarro-Guajardo
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA; ANID - Millennium Science Initiative Program - Millennium Nucleus in the Biology of the Intestinal Microbiota, Santiago, Chile
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5
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Andras JP, Fields PD, Du Pasquier L, Fredericksen M, Ebert D. Genome-Wide Association Analysis Identifies a Genetic Basis of Infectivity in a Model Bacterial Pathogen. Mol Biol Evol 2021; 37:3439-3452. [PMID: 32658956 PMCID: PMC7743900 DOI: 10.1093/molbev/msaa173] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/22/2020] [Accepted: 07/08/2020] [Indexed: 12/22/2022] Open
Abstract
Knowledge of the genetic architecture of pathogen infectivity and host resistance is essential for a mechanistic understanding of coevolutionary processes, yet the genetic basis of these interacting traits remains unknown for most host-pathogen systems. We used a comparative genomic approach to explore the genetic basis of infectivity in Pasteuria ramosa, a Gram-positive bacterial pathogen of planktonic crustaceans that has been established as a model for studies of Red Queen host-pathogen coevolution. We sequenced the genomes of a geographically, phenotypically, and genetically diverse collection of P. ramosa strains and performed a genome-wide association study to identify genetic correlates of infection phenotype. We found multiple polymorphisms within a single gene, Pcl7, that correlate perfectly with one common and widespread infection phenotype. We then confirmed this perfect association via Sanger sequencing in a large and diverse sample set of P. ramosa clones. Pcl7 codes for a collagen-like protein, a class of adhesion proteins known or suspected to be involved in the infection mechanisms of a number of important bacterial pathogens. Consistent with expectations under Red Queen coevolution, sequence variation of Pcl7 shows evidence of balancing selection, including extraordinarily high diversity and absence of geographic structure. Based on structural homology with a collagen-like protein of Bacillus anthracis, we propose a hypothesis for the structure of Pcl7 and the physical location of the phenotype-associated polymorphisms. Our results offer strong evidence for a gene governing infectivity and provide a molecular basis for further study of Red Queen dynamics in this model host-pathogen system.
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Affiliation(s)
- Jason P Andras
- Department of Biological Sciences, Mount Holyoke College, South Hadley, MA
| | - Peter D Fields
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Louis Du Pasquier
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Maridel Fredericksen
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Dieter Ebert
- Division of Zoology, Department of Environmental Sciences, University of Basel, Basel, Switzerland
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6
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Qiu Y, Zhai C, Chen L, Liu X, Yeo J. Current Insights on the Diverse Structures and Functions in Bacterial Collagen-like Proteins. ACS Biomater Sci Eng 2021. [PMID: 33871954 DOI: 10.1021/acsbiomaterials.1c00018] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The dearth of knowledge on the diverse structures and functions in bacterial collagen-like proteins is in stark contrast to the deep grasp of structures and functions in mammalian collagen, the ubiquitous triple-helical scleroprotein that plays a central role in tissue architecture, extracellular matrix organization, and signal transduction. To fill and highlight existing gaps due to the general paucity of data on bacterial CLPs, we comprehensively reviewed the latest insight into their functional and structural diversity from multiple perspectives of biology, computational simulations, and materials engineering. The origins and discovery of bacterial CLPs were explored. Their genetic distribution and molecular architecture were analyzed, and their structural and functional diversity in various bacterial genera was examined. The principal roles of computational techniques in understanding bacterial CLPs' structural stability, mechanical properties, and biological functions were also considered. This review serves to drive further interest and development of bacterial CLPs, not only for addressing fundamental biological problems in collagen but also for engineering novel biomaterials. Hence, both biology and materials communities will greatly benefit from intensified research into the diverse structures and functions in bacterial collagen-like proteins.
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Affiliation(s)
- Yimin Qiu
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, PR China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Chenxi Zhai
- J2 Lab for Engineering Living Materials, Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14850, United States
| | - Ling Chen
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, PR China
| | - Xiaoyan Liu
- National Biopesticide Engineering Technology Research Center, Hubei Biopesticide Engineering Research Center, Hubei Academy of Agricultural Sciences, Biopesticide Branch of Hubei Innovation Centre of Agricultural Science and Technology, Wuhan 430064, PR China
| | - Jingjie Yeo
- J2 Lab for Engineering Living Materials, Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York 14850, United States
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7
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Kananavičiūtė R, Kvederavičiūtė K, Dabkevičienė D, Mackevičius G, Kuisienė N. Collagen-like sequences encoded by extremophilic and extremotolerant bacteria. Genomics 2019; 112:2271-2281. [PMID: 31884159 DOI: 10.1016/j.ygeno.2019.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 12/17/2019] [Accepted: 12/25/2019] [Indexed: 12/14/2022]
Abstract
Collagens and collagen-like proteins are found in a wide range of organisms. The common feature of these proteins is a triple helix fold, requiring a characteristic pattern of amino acid sequences, composed of Gly-X-Y tripeptide repeats. Collagen-like proteins from bacteria are heterogeneous in terms of length and amino acid composition of their collagenous sequences. However, different bacteria live in different environments, some at extreme temperatures and conditions. This study explores the occurrence of collagen-like sequences in the genomes of different extreme condition-adapted bacteria, and investigates features that could be linked to conditions where they thrive. Our results show that proteins containing collagen-like sequences are encoded by genomes of various extremophiles. Some of these proteins contain conservative domains, characteristic of cell or endospore surface proteins, while most other proteins are unknown. The characteristics of collagenous sequences may depend on both, the phylogenetic relationship and the living conditions of the bacteria.
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Affiliation(s)
- Rūta Kananavičiūtė
- Institute of Biosciences, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT- 10257 Vilnius, Lithuania.
| | - Kotryna Kvederavičiūtė
- Institute of Biotechnology Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT- 10257 Vilnius, Lithuania
| | - Daiva Dabkevičienė
- Institute of Biosciences, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT- 10257 Vilnius, Lithuania
| | - Gytis Mackevičius
- Faculty of Mathematics and Informatics, Vilnius University, Naugarduko g. 24, LT-03225 Vilnius, Lithuania
| | - Nomeda Kuisienė
- Institute of Biosciences, Life Sciences Center, Vilnius University, Saulėtekio av. 7, LT- 10257 Vilnius, Lithuania
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8
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Ndumnego OC, Koehler SM, Crafford JE, Beyer W, van Heerden H. Immunogenicity of anthrax recombinant peptides and killed spores in goats and protective efficacy of immune sera in A/J mouse model. Sci Rep 2018; 8:16937. [PMID: 30446695 PMCID: PMC6240085 DOI: 10.1038/s41598-018-35382-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 11/02/2018] [Indexed: 11/09/2022] Open
Abstract
Anthrax is primarily recognized as an affliction of herbivores with incubation period ranging from three to five days post-infection. Currently, the Sterne live-spore vaccine is the only vaccine approved for control of the disease in susceptible animals. While largely effective, the Sterne vaccine has several problems including adverse reactions in sensitive species, ineffectiveness in active outbreaks and incompatibility with antibiotics. These can be surmounted with the advent of recombinant peptides (non-living) next generation vaccines. The candidate vaccine antigens comprised of recombinant protective antigen (PA), spore-specific antigen (bacillus collagen-like protein of anthracis, BclA) and formaldehyde inactivated spores (FIS). Presently, little information exists on the protectivity of these novel vaccine candidates in susceptible ruminants. Thus, this study sought to assess the immunogenicity of these vaccine candidates in goats and evaluate their protectivity using an in vivo mouse model. Goats receiving a combination of PA, BclA and FIS yielded the highest antibody and toxin neutralizing titres compared to recombinant peptides alone. This was also reflected in the passive immunization experiment whereby mice receiving immune sera from goats vaccinated with the antigen combination had higher survival post-challenge. In conclusion, the current data indicate promising potential for further development of non-living anthrax vaccines in ruminants.
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Affiliation(s)
- Okechukwu C Ndumnego
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, South Africa. .,Africa Health Research Institute, Durban, South Africa.
| | - Susanne M Koehler
- Institute of Animal Science, Department of Livestock Infectiology and Environmental Hygiene, University of Hohenheim, Stuttgart, Germany.,Robert Koch Institute, Berlin, Germany
| | - Jannie E Crafford
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, South Africa
| | - Wolfgang Beyer
- Institute of Animal Science, Department of Livestock Infectiology and Environmental Hygiene, University of Hohenheim, Stuttgart, Germany
| | - Henriette van Heerden
- Department of Veterinary Tropical Diseases, University of Pretoria, Onderstepoort, South Africa.
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9
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McNitt DH, Choi SJ, Keene DR, Van De Water L, Squeglia F, Berisio R, Lukomski S. Surface-exposed loops and an acidic patch in the Scl1 protein of group A Streptococcus enable Scl1 binding to wound-associated fibronectin. J Biol Chem 2018; 293:7796-7810. [PMID: 29615492 DOI: 10.1074/jbc.ra118.002250] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/29/2018] [Indexed: 12/22/2022] Open
Abstract
Keratinized epidermis constitutes a powerful barrier of the mucosa and skin, effectively preventing bacterial invasion, unless it is wounded and no longer protective. Wound healing involves deposition of distinct extracellular matrix (ECM) proteins enriched in cellular fibronectin (cFn) isoforms containing extra domain A (EDA). The streptococcal collagen-like protein 1 (Scl1) is a surface adhesin of group A Streptococcus (GAS), which contains an N-terminal variable (V) domain and a C-terminally located collagen-like domain. During wound infection, Scl1 selectively binds EDA/cFn isoforms and laminin, as well as low-density lipoprotein (LDL), through its V domain. The trimeric V domain has a six-helical bundle fold composed of three pairs of anti-parallel α-helices interconnected by hypervariable loops, but the roles of these structures in EDA/cFn binding are unclear. Here, using recombinant Scl (rScl) constructs to investigate structure-function determinants of the Scl1-EDA/cFn interaction, we found that full-length rScl1, containing both the globular V and the collagen domains, is necessary for EDA/cFn binding. We established that the surface-exposed loops, interconnecting conserved α-helices, guide recognition and binding of Scl1-V to EDA and binding to laminin and LDL. Moreover, electrostatic surface potential models of the Scl1-V domains pointed to a conserved, negatively charged pocket, surrounded by positively charged and neutral regions, as a determining factor for the binding. In light of these findings, we propose an updated model of EDA/cFn recognition by the Scl1 adhesin from GAS, representing a significant step in understanding the Scl1-ECM interactions within the wound microenvironment that underlie GAS pathogenesis.
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Affiliation(s)
- Dudley H McNitt
- From the Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia 26506
| | - Soo Jeon Choi
- From the Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia 26506
| | - Douglas R Keene
- the Micro-imaging Center, Shriners Hospital for Children, Portland, Oregon 97239
| | - Livingston Van De Water
- the Departments of Surgery and Regenerative and Cancer Cell Biology, Albany Medical College, Albany, New York 12208, and
| | - Flavia Squeglia
- the Institute of Biostructures and Bioimaging, Italian National Research Council, Via Mezzocannone 16, I-80134 Naples, Italy
| | - Rita Berisio
- the Institute of Biostructures and Bioimaging, Italian National Research Council, Via Mezzocannone 16, I-80134 Naples, Italy
| | - Slawomir Lukomski
- From the Department of Microbiology, Immunology, and Cell Biology, West Virginia University School of Medicine, Morgantown, West Virginia 26506,
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10
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Golser AV, Röber M, Börner HG, Scheibel T. Engineered Collagen: A Redox Switchable Framework for Tunable Assembly and Fabrication of Biocompatible Surfaces. ACS Biomater Sci Eng 2017; 4:2106-2114. [DOI: 10.1021/acsbiomaterials.7b00583] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Adrian V. Golser
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
| | - Matthias Röber
- Laboratory for Organic Synthesis of Functional Systems, Department of Chemistry Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Hans G. Börner
- Laboratory for Organic Synthesis of Functional Systems, Department of Chemistry Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin, Germany
| | - Thomas Scheibel
- Lehrstuhl Biomaterialien, Fakultät für Ingenieurwissenschaften Universität Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
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11
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Schnicker NJ, Razzaghi M, Guha Thakurta S, Chakravarthy S, Dey M. Bacillus anthracis Prolyl 4-Hydroxylase Interacts with and Modifies Elongation Factor Tu. Biochemistry 2017; 56:5771-5785. [PMID: 28981257 DOI: 10.1021/acs.biochem.7b00601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Prolyl hydroxylation is a very common post-translational modification and plays many roles in eukaryotes such as collagen stabilization, hypoxia sensing, and controlling protein transcription and translation. There is a growing body of evidence that suggests that prokaryotes contain prolyl 4-hydroxylases (P4Hs) homologous to the hypoxia-inducible factor (HIF) prolyl hydroxylase domain (PHD) enzymes that act on elongation factor Tu (EFTu) and are likely involved in the regulation of bacterial translation. Recent biochemical and structural studies with a PHD from Pseudomonas putida (PPHD) determined that it forms a complex with EFTu and hydroxylates a prolyl residue of EFTu. Moreover, while animal, plant, and viral P4Hs act on peptidyl proline, most prokaryotic P4Hs have been known to target free l-proline; the exceptions include PPHD and a P4H from Bacillus anthracis (BaP4H) that modifies collagen-like proline-rich peptides. Here we use biophysical and mass spectrometric methods to demonstrate that BaP4H recognizes full-length BaEFTu and a BaEFTu 9-mer peptide for site-specific proline hydroxylation. Using size-exclusion chromatography coupled small-angle X-ray scattering (SEC-SAXS) and binding studies, we determined that BaP4H forms a 1:1 heterodimeric complex with BaEFTu. The SEC-SAXS studies reveal dissociation of BaP4H dimeric subunits upon interaction with BaEFTu. While BaP4H is unusual within bacteria in that it is structurally and functionally similar to the animal PHDs and collagen P4Hs, respectively, this work provides further evidence of its promiscuous substrate recognition. It is possible that the enzyme might have evolved to hydroxylate a universally conserved protein in prokaryotes, similar to the PHDs, and implies a functional role in B. anthracis.
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Affiliation(s)
- Nicholas J Schnicker
- Department of Chemistry, The University of Iowa , Iowa City, Iowa 52242, United States
| | - Mortezaali Razzaghi
- Department of Chemistry, The University of Iowa , Iowa City, Iowa 52242, United States
| | - Sanjukta Guha Thakurta
- Department of Cell Biology, Harvard Medical School , 240 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Srinivas Chakravarthy
- Biophysics Collaborative Access Team, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Mishtu Dey
- Department of Chemistry, The University of Iowa , Iowa City, Iowa 52242, United States
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Abstract
In some Bacillus species, including Bacillus subtilis, the coat is the outermost layer of the spore. In others, such as the Bacillus cereus family, there is an additional layer that envelops the coat, called the exosporium. In the case of Bacillus anthracis, a series of fine hair-like projections, also referred to as a "hairy" nap, extends from the exosporium basal layer. The exact role of the exosporium in B. anthracis, or for any of the Bacillus species possessing this structure, remains unclear. However, it has been assumed that the exosporium would play some role in infection for B. anthracis, because it is the outermost structure of the spore and would make initial contact with host and immune cells during infection. Therefore, the exosporium has been a topic of great interest, and over the past decade much progress has been made to understand its composition, biosynthesis, and potential roles. Several key aspects of this spore structure, however, are still debated and remain undetermined. Although insights have been gained on the interaction of exosporium with the host during infection, the exact role and significance of this complex structure remain to be determined. Furthermore, because the exosporium is a highly antigenic structure, future strategies for the next-generation anthrax vaccine should pursue its inclusion as a component to provide protection against the spore itself during the initial stages of anthrax.
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13
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The Exosporium Layer of Bacterial Spores: a Connection to the Environment and the Infected Host. Microbiol Mol Biol Rev 2016; 79:437-57. [PMID: 26512126 DOI: 10.1128/mmbr.00050-15] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Much of what we know regarding bacterial spore structure and function has been learned from studies of the genetically well-characterized bacterium Bacillus subtilis. Molecular aspects of spore structure, assembly, and function are well defined. However, certain bacteria produce spores with an outer spore layer, the exosporium, which is not present on B. subtilis spores. Our understanding of the composition and biological functions of the exosporium layer is much more limited than that of other aspects of the spore. Because the bacterial spore surface is important for the spore's interactions with the environment, as well as being the site of interaction of the spore with the host's innate immune system in the case of spore-forming bacterial pathogens, the exosporium is worthy of continued investigation. Recent exosporium studies have focused largely on members of the Bacillus cereus family, principally Bacillus anthracis and Bacillus cereus. Our understanding of the composition of the exosporium, the pathway of its assembly, and its role in spore biology is now coming into sharper focus. This review expands on a 2007 review of spore surface layers which provided an excellent conceptual framework of exosporium structure and function (A. O. Henriques and C. P. Moran, Jr., Annu Rev Microbiol 61:555-588, 2007, http://dx.doi.org/10.1146/annurev.micro.61.080706.093224). That review began a process of considering outer spore layers as an integrated, multilayered structure rather than simply regarding the outer spore components as independent parts.
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Maes E, Krzewinski F, Garenaux E, Lequette Y, Coddeville B, Trivelli X, Ronse A, Faille C, Guerardel Y. Glycosylation of BclA Glycoprotein from Bacillus cereus and Bacillus anthracis Exosporium Is Domain-specific. J Biol Chem 2016; 291:9666-77. [PMID: 26921321 DOI: 10.1074/jbc.m116.718171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Indexed: 11/06/2022] Open
Abstract
The spores of the Bacillus cereus group (B. cereus, Bacillus anthracis, and Bacillus thuringiensis) are surrounded by a paracrystalline flexible yet resistant layer called exosporium that plays a major role in spore adhesion and virulence. The major constituent of its hairlike surface, the trimerized glycoprotein BclA, is attached to the basal layer through an N-terminal domain. It is then followed by a repetitive collagen-like neck bearing a globular head (C-terminal domain) that promotes glycoprotein trimerization. The collagen-like region of B. anthracis is known to be densely substituted by unusual O-glycans that may be used for developing species-specific diagnostics of B. anthracis spores and thus targeted therapeutic interventions. In the present study, we have explored the species and domain specificity of BclA glycosylation within the B. cereus group. First, we have established that the collagen-like regions of both B. anthracis and B. cereus are similarly substituted by short O-glycans that bear the species-specific deoxyhexose residues anthrose and the newly observed cereose, respectively. Second we have discovered that the C-terminal globular domains of BclA from both species are substituted by polysaccharide-like O-linked glycans whose structures are also species-specific. The presence of large carbohydrate polymers covering the surface of Bacillus spores may have a profound impact on the way that spores regulate their interactions with biotic and abiotic surfaces and represents potential new diagnostic targets.
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Affiliation(s)
- Emmanuel Maes
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | - Frederic Krzewinski
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | - Estelle Garenaux
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | | | - Bernadette Coddeville
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | - Xavier Trivelli
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | | | | | - Yann Guerardel
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
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Yu Z, An B, Ramshaw JA, Brodsky B. Bacterial collagen-like proteins that form triple-helical structures. J Struct Biol 2014; 186:451-61. [DOI: 10.1016/j.jsb.2014.01.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 01/09/2014] [Accepted: 01/09/2014] [Indexed: 02/06/2023]
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Abstract
Maintaining proper energy balance in mammals entails intimate crosstalk between various tissues and organs. These inter-organ communications are mediated, to a great extent, by secreted hormones that circulate in blood. Regulation of the complex metabolic networks by secreted hormones (e.g., insulin, glucagon, leptin, adiponectin, FGF21) constitutes an important mechanism governing the integrated control of whole-body metabolism. Disruption of hormone-mediated metabolic circuits frequently results in dysregulated energy metabolism and pathology. As part of an effort to identify novel metabolic hormones, we recently characterized a highly conserved family of 15 secreted proteins, the C1q/TNF-related proteins (CTRP1-15). While related to adiponectin in sequence and structural organization, each CTRP has its own unique tissue expression profile and non-redundant function in regulating sugar and/or fat metabolism. Here, we summarize the current understanding of the physiological functions of CTRPs, emphasizing their metabolic roles. Future studies using gain-of-function and loss-of-function mouse models will provide greater mechanistic insights into the critical role CTRPs play in regulating systemic energy homeostasis.
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Affiliation(s)
- Marcus M Seldin
- Department of Physiology and Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
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17
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Rodenburg CM, McPherson SA, Turnbough CL, Dokland T. Cryo-EM analysis of the organization of BclA and BxpB in the Bacillus anthracis exosporium. J Struct Biol 2014; 186:181-7. [PMID: 24607412 DOI: 10.1016/j.jsb.2014.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 02/25/2014] [Accepted: 02/28/2014] [Indexed: 10/25/2022]
Abstract
Bacillus anthracis and other pathogenic Bacillus species form spores that are surrounded by an exosporium, a balloon-like layer that acts as the outer permeability barrier of the spore and contributes to spore survival and virulence. The exosporium consists of a hair-like nap and a paracrystalline basal layer. The filaments of the nap are comprised of trimers of the collagen-like glycoprotein BclA, while the basal layer contains approximately 20 different proteins. One of these proteins, BxpB, forms tight complexes with BclA and is required for attachment of essentially all BclA filaments to the basal layer. Another basal layer protein, ExsB, is required for the stable attachment of the exosporium to the spore. To determine the organization of BclA and BxpB within the exosporium, we used cryo-electron microscopy, cryo-sectioning and crystallographic analysis of negatively stained exosporium fragments to compare wildtype spores and mutant spores lacking BclA, BxpB or ExsB (ΔbclA, ΔbxpB and ΔexsB spores, respectively). The trimeric BclA filaments are attached to basal layer surface protrusions that appear to be trimers of BxpB. The protrusions interact with a crystalline layer of hexagonal subunits formed by other basal layer proteins. Although ΔbxpB spores retain the hexagonal subunits, the basal layer is not organized with crystalline order and lacks basal layer protrusions and most BclA filaments, indicating a central role for BxpB in exosporium organization.
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Affiliation(s)
- Cynthia M Rodenburg
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Sylvia A McPherson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Charles L Turnbough
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Terje Dokland
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Tournier JN, Ulrich RG, Quesnel-Hellmann A, Mohamadzadeh M, Stiles BG. Anthrax, toxins and vaccines: a 125-year journey targetingBacillus anthracis. Expert Rev Anti Infect Ther 2014; 7:219-36. [DOI: 10.1586/14787210.7.2.219] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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19
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Squeglia F, Bachert B, De Simone A, Lukomski S, Berisio R. The crystal structure of the streptococcal collagen-like protein 2 globular domain from invasive M3-type group A Streptococcus shows significant similarity to immunomodulatory HIV protein gp41. J Biol Chem 2013; 289:5122-33. [PMID: 24356966 DOI: 10.1074/jbc.m113.523597] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The arsenal of virulence factors deployed by streptococci includes streptococcal collagen-like (Scl) proteins. These proteins, which are characterized by a globular domain and a collagen-like domain, play key roles in host adhesion, host immune defense evasion, and biofilm formation. In this work, we demonstrate that the Scl2.3 protein is expressed on the surface of invasive M3-type strain MGAS315 of Streptococcus pyogenes. We report the crystal structure of Scl2.3 globular domain, the first of any Scl. This structure shows a novel fold among collagen trimerization domains of either bacterial or human origin. Despite there being low sequence identity, we observed that Scl2.3 globular domain structurally resembles the gp41 subunit of the envelope glycoprotein from human immunodeficiency virus type 1, an essential subunit for viral fusion to human T cells. We combined crystallographic data with modeling and molecular dynamics techniques to gather information on the entire lollipop-like Scl2.3 structure. Molecular dynamics data evidence a high flexibility of Scl2.3 with remarkable interdomain motions that are likely instrumental to the protein biological function in mediating adhesive or immune-modulatory functions in host-pathogen interactions. Altogether, our results provide molecular tools for the understanding of Scl-mediated streptococcal pathogenesis and important structural insights for the future design of small molecular inhibitors of streptococcal invasion.
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Affiliation(s)
- Flavia Squeglia
- From the Institute of Biostructures and Bioimaging, Consiglio Nazionale delle Ricerche, Via Mezzocannone 16, I-80134 Napoli, Italy
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Abhyankar W, Hossain AH, Djajasaputra A, Permpoonpattana P, Ter Beek A, Dekker HL, Cutting SM, Brul S, de Koning LJ, de Koster CG. In Pursuit of Protein Targets: Proteomic Characterization of Bacterial Spore Outer Layers. J Proteome Res 2013; 12:4507-21. [DOI: 10.1021/pr4005629] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | | | - Patima Permpoonpattana
- School
of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
| | | | | | - Simon M. Cutting
- School
of Biological Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
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21
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Galaleldeen A, Taylor AB, Chen D, Schuermann JP, Holloway SP, Hou S, Gong S, Zhong G, Hart PJ. Structure of the Chlamydia trachomatis immunodominant antigen Pgp3. J Biol Chem 2013; 288:22068-79. [PMID: 23703617 DOI: 10.1074/jbc.m113.475012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chlamydia trachomatis infection is the most common sexually transmitted bacterial disease. Left untreated, it can lead to ectopic pregnancy, pelvic inflammatory disease, and infertility. Here we present the structure of the secreted C. trachomatis protein Pgp3, an immunodominant antigen and putative virulence factor. The ∼84-kDa Pgp3 homotrimer, encoded on a cryptic plasmid, consists of globular N- and C-terminal assemblies connected by a triple-helical coiled-coil. The C-terminal domains possess folds similar to members of the TNF family of cytokines. The closest Pgp3 C-terminal domain structural homologs include a lectin from Burkholderia cenocepacia, the C1q component of complement, and a portion of the Bacillus anthracis spore surface protein BclA, all of which play roles in bioadhesion. The N-terminal domain consists of a concatenation of structural motifs typically found in trimeric viral proteins. The central parallel triple-helical coiled-coil contains an unusual alternating pattern of apolar and polar residue pairs that generate a rare right-handed superhelical twist. The unique architecture of Pgp3 provides the basis for understanding its role in chlamydial pathogenesis and serves as the platform for its optimization as a potential vaccine antigen candidate.
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Affiliation(s)
- Ahmad Galaleldeen
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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22
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Ghebrehiwet B, Jesty J, Vinayagasundaram R, Vinayagasundaram U, Ji Y, Valentino A, Tumma N, Hosszu KH, Peerschke EIB. Targeting gC1qR Domains for Therapy Against Infection and Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 735:97-110. [DOI: 10.1007/978-1-4614-4118-2_6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Gu C, Jenkins SA, Xue Q, Xu Y. Activation of the classical complement pathway by Bacillus anthracis is the primary mechanism for spore phagocytosis and involves the spore surface protein BclA. THE JOURNAL OF IMMUNOLOGY 2012; 188:4421-31. [PMID: 22442442 DOI: 10.4049/jimmunol.1102092] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Interactions between spores of Bacillus anthracis and macrophages are critical for the development of anthrax infections, as spores are thought to use macrophages as vehicles to disseminate in the host. In this study, we report a novel mechanism for phagocytosis of B. anthracis spores. Murine macrophage-like cell line RAW264.7, bone marrow-derived macrophages, and primary peritoneal macrophages from mice were used. The results indicated that activation of the classical complement pathway (CCP) was a primary mechanism for spore phagocytosis. Phagocytosis was significantly reduced in the absence of C1q or C3. C3 fragments were found deposited on the spore surface, and the deposition was dependent on C1q and Ca(2+). C1q recruitment to the spore surface was mediated by the spore surface protein BclA, as recombinant BclA bound directly and specifically to C1q and inhibited C1q binding to spores in a dose-dependent manner. C1q binding to spores lacking BclA (ΔbclA) was also significantly reduced compared with wild-type spores. In addition, deposition of both C3 and C4 as well as phagocytosis of spores were significantly reduced when BclA was absent, but were not reduced in the absence of IgG, suggesting that BclA, but not IgG, is important in these processes. Taken together, these results support a model in which spores actively engage CCP primarily through BclA interaction with C1q, leading to CCP activation and opsonophagocytosis of spores in an IgG-independent manner. These findings are likely to have significant implications on B. anthracis pathogenesis and microbial manipulation of complement.
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Affiliation(s)
- Chunfang Gu
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
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24
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Criteria for selection of surrogates used to study the fate and control of pathogens in the environment. Appl Environ Microbiol 2012; 78:1969-77. [PMID: 22247166 DOI: 10.1128/aem.06582-11] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This article defines the term surrogate as an organism, particle, or substance used to study the fate of a pathogen in a specific environment. Pathogenic organisms, nonpathogenic organisms, and innocuous particles have been used as surrogates for a variety of purposes, including studies on survival and transport as well as for method development and as "indicators" of certain conditions. This article develops a qualitative surrogate attribute prioritization process and allows investigators to select a surrogate by systematically detailing the experimental process and prioritizing attributes. The results are described through the use of case studies of various laboratories that have used this process. This article also discusses the history of surrogate and microbial indicator use and outlines the method by which surrogates can be used when conducting a quantitative microbial risk assessment. The ultimate goal of selecting a sufficiently representative surrogate is to improve public health through a health-based risk assessment framework. Under- or overestimating the resistance, inactivation, or movement may negatively impact risk assessments that, in turn, will impact health assessments and estimated safety levels. Reducing uncertainty in a risk assessment is one of the objectives of using surrogates and the ultimate motive for any experiment investigating potential exposure of a pathogen.
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Ghebrehiwet B, Hosszu KK, Valentino A, Peerschke EIB. The C1q family of proteins: insights into the emerging non-traditional functions. Front Immunol 2012; 3. [PMID: 22536204 PMCID: PMC3334295 DOI: 10.3389/fimmu.2012.00052] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Research conducted over the past 20 years have helped us unravel not only the hidden structural and functional subtleties of human C1q, but also has catapulted the molecule from a mere recognition unit of the classical pathway to a well-recognized molecular sensor of damage-modified self or non-self antigens. Thus, C1q is involved in a rapidly expanding list of pathological disorders – including autoimmunity, trophoblast migration, preeclampsia, and cancer. The results of two recent reports are provided to underscore the critical role C1q plays in health and disease. First is the observation by Singh et al. (2011) showing that pregnant C1q−/− mice recapitulate the key features of human preeclampsia that correlate with increased fetal death. Treatment of the C1q−/− mice with pravastatin restored trophoblast invasiveness, placental blood flow, and angiogenic balance and, thus, prevented the onset of preeclampsia. Second is the report by Hong et al. (2009) which showed that C1q can induce apoptosis of prostate cancer cells by activating the tumor suppressor molecule WW-domain containing oxydoreductase (WWOX or WOX1) and destabilizing cell adhesion. Downregulation of C1q on the other hand, enhanced prostate hyperplasia and cancer formation due to failure of WOX1 activation. C1q belongs to a family of structurally and functionally related TNF-α-like family of proteins that may have arisen from a common ancestral gene. Therefore C1q not only shares the diverse functions with the tumor necrosis factor family of proteins, but also explains why C1q has retained some of its ancestral “cytokine-like” activities. This review is intended to highlight some of the structural and functional aspects of C1q by underscoring the growing list of its non-traditional functions.
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26
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Boudko SP, Engel J, Bächinger HP. The crucial role of trimerization domains in collagen folding. Int J Biochem Cell Biol 2012; 44:21-32. [DOI: 10.1016/j.biocel.2011.09.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Revised: 09/27/2011] [Accepted: 09/27/2011] [Indexed: 10/17/2022]
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Surface architecture of endospores of the Bacillus cereus/anthracis/thuringiensis family at the subnanometer scale. Proc Natl Acad Sci U S A 2011; 108:16014-9. [PMID: 21896762 DOI: 10.1073/pnas.1109419108] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Bacillus cereus family form highly resistant spores, which in the case of the pathogen B. anthracis act as the agents of infection. The outermost layer, the exosporium, enveloping spores of the B. cereus family as well as a number of Clostridia, plays roles in spore adhesion, dissemination, targeting, and germination control. We have analyzed two naturally crystalline layers associated with the exosporium, one representing the "basal" layer to which the outermost spore layer ("hairy nap") is attached, and the other likely representing a subsurface ("parasporal") layer. We have used electron cryomicroscopy at a resolution of 0.8-0.6 nm and circular dichroism spectroscopic measurements to reveal a highly α-helical structure for both layers. The helices are assembled into 2D arrays of "cups" or "crowns." High-resolution atomic force microscopy of the outermost layer showed that the open ends of these cups face the external environment and the highly immunogenic collagen-like fibrils of the hairy nap (BclA) are attached to this surface. Based on our findings, we present a molecular model for the spore surface and propose how this surface can act as a semipermeable barrier and a matrix for binding of molecules involved in defense, germination control, and other interactions of the spore with the environment.
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Lequette Y, Garénaux E, Combrouse T, Dias TDL, Ronse A, Slomianny C, Trivelli X, Guerardel Y, Faille C. Domains of BclA, the major surface glycoprotein of the B. cereus exosporium: glycosylation patterns and role in spore surface properties. BIOFOULING 2011; 27:751-761. [PMID: 21777114 DOI: 10.1080/08927014.2011.599842] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The role of the BclA domains of B. cereus ATCC 14579 was investigated in order to understand the phenomena involved in the interfacial processes occurring between spores and inert surfaces. This was done by (i) creating deletions in the collagen-like region (CLR) and the C-terminal domain (CTD) of BclA, (ii) building BclA proteins with various lengths in the CLR and (iii) modifying the hydrophobic upper surface in the CTD. First, it was demonstrated that the CLR was substituted by three residues already reported in the CLR of B. anthracis, viz. rhamnose, 3-O-methyl-rhamnose, and GalNH(2) residues, while the CTD was also substituted by two additional glycosyl residues, viz. 2-O-methyl-rhamnose and 2,4-O-methyl-rhamnose. Regarding the properties of the spores, both CLR and CTD contributed to the adhesion of the spores, which was estimated by measuring the resistance to detachment of spores adhered to stainless steel plates). CLR and CTD also impacted the hydrophobic character and isoelectric point of the spores. It was then shown that the resistance to detachment of the spores was not affected by the physicochemical properties, but by the CLR length and the presence of hydrophobic amino acids on the CTD.
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Affiliation(s)
- Yannick Lequette
- INRA, UR638 PIHM (Interface Processes and Hygiene of Materials), 369 rue Jules Guesde, F-59651 Villeneuve d'Ascq , France
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Role played by exosporium glycoproteins in the surface properties of Bacillus cereus spores and in their adhesion to stainless steel. Appl Environ Microbiol 2011; 77:4905-11. [PMID: 21622795 DOI: 10.1128/aem.02872-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus cereus spores are surrounded by a loose-fitting layer called the exosporium, whose distal part is mainly formed from glycoproteins. The role played by the exosporium glycoproteins of B. cereus ATCC 14579 (BclA and ExsH) was investigated by considering hydrophobicity and charge, as well as the properties of spore adhesion to stainless steel. The absence of BclA increased both the isoelectric point (IEP) and hydrophobicity of whole spores while simultaneously reducing the interaction between spores and stainless steel. However, neither the hydrophobicity nor the charge associated with BclA could explain the differences in the adhesion properties. Conversely, ExsH, another exosporium glycoprotein, did not play a significant role in spore surface properties. The monosaccharide analysis of B. cereus ATCC 14579 showed different glycosylation patterns on ExsH and BclA. Moreover, two specific glycosyl residues, namely, 2-O-methyl-rhamnose (2-Me-Rha) and 2,4-O-methyl-rhamnose (2,4-Me-Rha), were attached to BclA, in addition to the glycosyl residues already reported in B. anthracis.
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Nuttall SD, Wilkins ML, Streltsov VA, Pontes-Braz L, Dolezal O, Tran H, Liu CQ. Isolation, kinetic analysis, and structural characterization of an antibody targeting the Bacillus anthracis major spore surface protein BclA. Proteins 2011; 79:1306-17. [PMID: 21322055 DOI: 10.1002/prot.22971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 11/10/2010] [Indexed: 11/11/2022]
Abstract
One method of laboratory- or field-based testing for anthrax is detection of Bacillus anthracis spores by high-affinity, high specificity binding reagents. From a pool of monoclonal antibodies, we selected one such candidate (A4D11) with high affinity for tBclA, a truncated version of the B. anthracis exosporium protein BclA. Kinetic analysis utilising both standard and kinetic titration on a Biacore biosensor indicated antibody affinities in the 300 pM range for recombinant tBclA, and the A4D11 antibody was also re-formatted into scFv configuration with no loss of affinity. However, assays against B. anthracis and related Bacilli species showed limited binding of intact spores as well as significant cross-reactivity between species. These results were rationalized by determination of the three-dimensional crystallographic structure of the scFv-tBclA complex. A4D11 binds the side of the tBclA trimer, contacting a face of the antigen normally packed against adjacent trimers within the exosporium structure; this inter-spore interface is highly conserved between Bacilli species. Our results indicate the difficulty of generating a high-affinity antibody to differentiate between the highly conserved spore structures of closely related species, but suggest the possibility of future structure-based antibody design for this difficult target.
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Affiliation(s)
- Stewart D Nuttall
- CSIRO Division of Materials Science and Engineering, Parkville, Victoria, 3052, Australia.
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Xue Q, Gu C, Rivera J, Höök M, Chen X, Pozzi A, Xu Y. Entry of Bacillus anthracis spores into epithelial cells is mediated by the spore surface protein BclA, integrin α2β1 and complement component C1q. Cell Microbiol 2010; 13:620-34. [PMID: 21134100 DOI: 10.1111/j.1462-5822.2010.01558.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Inhalational anthrax is initiated by pulmonary exposure to Bacillus anthracis spores. Spore entry into lung epithelial cells is observed both in vitro and in vivo and evidence suggests it is important for bacterial dissemination and virulence. However the specific host receptor and spore factor that mediate the entry process were unknown. Here, we report that integrin α2β1 is a major receptor for spore entry. This is supported by results from blocking antibodies, siRNA knock-down, colocalization, and comparison of spore entry into cells that do or do not express α2. BclA, a major spore surface protein, is found to be essential for entry and α2β1-mediated entry is dependent on BclA. However, BclA does not appear to bind directly to α2. Furthermore, spore entry into α2-expressing cells is dramatically reduced in the absence of serum, suggesting that additional factors are involved. Finally, complement component C1q, also an α2β1 ligand, appears to act as a bridging molecule or a cofactor for BclA/α2β1-mediated spore entry and BclA binds to C1q in a dose-dependent and saturable manner. These findings suggest a novel mechanism for pathogen entry into host cells as well as a new function for C1q-integrin interactions. The implications of these findings are discussed.
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Affiliation(s)
- Qiong Xue
- Center for Inflammatory and Infectious Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
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Yu Z, Mirochnitchenko O, Xu C, Yoshizumi A, Brodsky B, Inouye M. Noncollagenous region of the streptococcal collagen-like protein is a trimerization domain that supports refolding of adjacent homologous and heterologous collagenous domains. Protein Sci 2010; 19:775-85. [PMID: 20162611 DOI: 10.1002/pro.356] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Proper folding of the (Gly-Xaa-Yaa)(n) sequence of animal collagens requires adjacent N- or C-terminal noncollagenous trimerization domains which often contain coiled-coil or beta sheet structure. Collagen-like proteins have been found recently in a number of bacteria, but little is known about their folding mechanism. The Scl2 collagen-like protein from Streptococcus pyogenes has an N-terminal globular domain, designated V(sp), adjacent to its triple-helix domain. The V(sp) domain is required for proper refolding of the Scl2 protein in vitro. Here, recombinant V(sp) domain alone is shown to form trimers with a significant alpha-helix content and to have a thermal stability of T(m) = 45 degrees C. Examination of a new construct shows that the V(sp) domain facilitates efficient in vitro refolding only when it is located N-terminal to the triple-helix domain but not when C-terminal to the triple-helix domain. Fusion of the V(sp) domain N-terminal to a heterologous (Gly-Xaa-Yaa)(n) sequence from Clostridium perfringens led to correct folding and refolding of this triple-helix, which was unable to fold into a triple-helical, soluble protein on its own. These results suggest that placement of a functional trimerization module adjacent to a heterologous Gly-Xaa-Yaa repeating sequence can lead to proper folding in some cases but also shows specificity in the relative location of the trimerization and triple-helix domains. This information about their modular nature can be used in the production of novel types of bacterial collagen for biomaterial applications.
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Affiliation(s)
- Zhuoxin Yu
- Department of Biochemistry, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
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Greenberg DL, Busch JD, Keim P, Wagner DM. Identifying experimental surrogates for Bacillus anthracis spores: a review. INVESTIGATIVE GENETICS 2010; 1:4. [PMID: 21092338 PMCID: PMC2988482 DOI: 10.1186/2041-2223-1-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 09/01/2010] [Indexed: 01/05/2023]
Abstract
Bacillus anthracis, the causative agent of anthrax, is a proven biological weapon. In order to study this threat, a number of experimental surrogates have been used over the past 70 years. However, not all surrogates are appropriate for B. anthracis, especially when investigating transport, fate and survival. Although B. atrophaeus has been widely used as a B. anthracis surrogate, the two species do not always behave identically in transport and survival models. Therefore, we devised a scheme to identify a more appropriate surrogate for B. anthracis. Our selection criteria included risk of use (pathogenicity), phylogenetic relationship, morphology and comparative survivability when challenged with biocides. Although our knowledge of certain parameters remains incomplete, especially with regards to comparisons of spore longevity under natural conditions, we found that B. thuringiensis provided the best overall fit as a non-pathogenic surrogate for B. anthracis. Thus, we suggest focusing on this surrogate in future experiments of spore fate and transport modelling.
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Affiliation(s)
- David L Greenberg
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ 86011-4073, USA
| | - Joseph D Busch
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ 86011-4073, USA
| | | | - David M Wagner
- Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ 86011-4073, USA
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A TNF-like trimeric lectin domain from Burkholderia cenocepacia with specificity for fucosylated human histo-blood group antigens. Structure 2010; 18:59-72. [PMID: 20152153 DOI: 10.1016/j.str.2009.10.021] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 10/03/2009] [Accepted: 10/22/2009] [Indexed: 11/23/2022]
Abstract
The opportunistic pathogen Burkholderia cenocepacia expresses several soluble lectins, among them BC2L-C. This lectin exhibits two domains: a C-terminal domain with high sequence similarity to the recently described calcium-dependent mannose-binding lectin BC2L-A, and an N-terminal domain of 156 amino acids without similarity to any known protein. The recombinant N-terminal BC2L-C domain is a new lectin with specificity for fucosylated human histo-blood group epitopes H-type 1, Lewis b, and Lewis Y, as determined by glycan array and isothermal titration calorimetry. Methylselenofucoside was used as ligand to solve the crystal structure of the N-terminal BC2L-C domain. Additional molecular modeling studies rationalized the preference for Lewis epitopes. The structure reveals a trimeric jellyroll arrangement with striking similarity to TNF-like proteins, and to BclA, the spore protein from Bacillus anthracis which may play an important role in bioadhesion of anthrax spores in human lungs.
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Sequence motifs and proteolytic cleavage of the collagen-like glycoprotein BclA required for its attachment to the exosporium of Bacillus anthracis. J Bacteriol 2009; 192:1259-68. [PMID: 20038593 DOI: 10.1128/jb.01003-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus anthracis spores are enclosed by an exosporium comprised of a basal layer and an external hair-like nap. The filaments of the nap are composed of trimers of the collagen-like glycoprotein BclA. The attachment of essentially all BclA trimers to the exosporium requires the basal layer protein BxpB, and both proteins are included in stable high-molecular-mass exosporium complexes. BclA contains a proteolytically processed 38-residue amino-terminal domain (NTD) that is essential for basal-layer attachment. In this report, we identify three NTD submotifs (SM1a, SM1b, and SM2, located within residues 21 to 33) that are important for BclA attachment and demonstrate that residue A20, the amino-terminal residue of processed BclA, is not required for attachment. We show that the shortest NTD of BclA-or of a recombinant protein-sufficient for high-level basal-layer attachment is a 10-residue motif consisting of an initiating methionine, an apparently arbitrary second residue, SM1a or SM1b, and SM2. We also demonstrate that cleavage of the BclA NTD is necessary for efficient attachment to the basal layer and that the site of cleavage is somewhat flexible, at least in certain mutant NTDs. Finally, we propose a mechanism for BclA attachment and discuss the possibility that analogous mechanisms are involved in the attachment of many different collagen-like proteins of B. anthracis and closely related Bacillus species.
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Mouton L, Traunecker E, McElroy K, Du Pasquier L, Ebert D. Identification of a polymorphic collagen-like protein in the crustacean bacteria Pasteuria ramosa. Res Microbiol 2009; 160:792-9. [DOI: 10.1016/j.resmic.2009.08.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2009] [Revised: 08/10/2009] [Accepted: 08/26/2009] [Indexed: 11/24/2022]
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Identification and classification of bcl genes and proteins of Bacillus cereus group organisms and their application in Bacillus anthracis detection and fingerprinting. Appl Environ Microbiol 2009; 75:7163-72. [PMID: 19767469 DOI: 10.1128/aem.01069-09] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The Bacillus cereus group includes three closely related species, B. anthracis, B. cereus, and B. thuringiensis, which form a highly homogeneous subdivision of the genus Bacillus. One of these species, B. anthracis, has been identified as one of the most probable bacterial biowarfare agents. Here, we evaluate the sequence and length polymorphisms of the Bacillus collagen-like protein bcl genes as a basis for B. anthracis detection and fingerprinting. Five genes, designated bclA to bclE, are present in B. anthracis strains. Examination of bclABCDE sequences identified polymorphisms in bclB alleles of the B. cereus group organisms. These sequence polymorphisms allowed specific detection of B. anthracis strains by PCR using both genomic DNA and purified Bacillus spores in reactions. By exploiting the length variation of the bcl alleles it was demonstrated that the combined bclABCDE PCR products generate markedly different fingerprints for the B. anthracis Ames and Sterne strains. Moreover, we predict that bclABCDE length polymorphism creates unique signatures for B. anthracis strains, which facilitates identification of strains with specificity and confidence. Thus, we present a new diagnostic concept for B. anthracis detection and fingerprinting, which can be used alone or in combination with previously established typing platforms.
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Nicastro G, Orsomando G, Ferrari E, Manconi L, Desario F, Amici A, Naso A, Carpaneto A, Pertinhez TA, Ruggieri S, Spisni A. Solution structure of the phytotoxic protein PcF: the first characterized member of the Phytophthora PcF toxin family. Protein Sci 2009; 18:1786-91. [PMID: 19554629 PMCID: PMC2776965 DOI: 10.1002/pro.168] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 05/06/2009] [Indexed: 01/10/2023]
Abstract
The PcF protein from Phytophthora cactorum is the first member of the "PcF toxin family" from the plant pathogens Phytophthora spp. It is able to induce withering in tomato and strawberry leaves. The lack of sequence similarity with other proteins hampers the identification of the molecular mechanisms responsible for its toxicity. Here, we show that the six cysteines form a disulphide pattern that is exclusive for PcF and essential for the protein withering activity. The NMR solution structure identifies a novel fold among protein effectors: a helix-loop-helix motif. The presence of a negatively charged surface suggests that it might act as a site of electrostatic interaction. Interestingly, a good fold match with Ole e 6, a plant protein with allergenic activity, highlighted the spatial superimposition of a stretch of identical residues. This finding suggests a possible biological activity based on molecular mimicry.
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Affiliation(s)
- Giuseppe Nicastro
- National Institute for Medical Research (NIMR-MRC), The RidgewayLondon NW7 1AA, United Kingdom
- Centro Interdipartimentale Misure (CIM), Università di Parma43100 Parma, Italy
| | - Giuseppe Orsomando
- Istituto Biotecnologie Biochimiche, Università Politecnica delle Marche60131 Ancona, Italy
| | - Elena Ferrari
- Dipartimento Medicina Sperimentale, Università di Parma43100 Parma, Italy
| | - Lucia Manconi
- Istituto Biotecnologie Biochimiche, Università Politecnica delle Marche60131 Ancona, Italy
| | - Filomena Desario
- Istituto Biotecnologie Biochimiche, Università Politecnica delle Marche60131 Ancona, Italy
| | - Adolfo Amici
- Istituto Biotecnologie Biochimiche, Università Politecnica delle Marche60131 Ancona, Italy
| | - Alessia Naso
- Istituto Biofisica, Consiglio Nazionale Ricerche (CNR)16149 Genova, Italy
| | - Armando Carpaneto
- Istituto Biofisica, Consiglio Nazionale Ricerche (CNR)16149 Genova, Italy
| | - Thelma A Pertinhez
- Dipartimento Medicina Sperimentale, Università di Parma43100 Parma, Italy
| | - Silverio Ruggieri
- Istituto Biotecnologie Biochimiche, Università Politecnica delle Marche60131 Ancona, Italy
| | - Alberto Spisni
- Dipartimento Medicina Sperimentale, Università di Parma43100 Parma, Italy
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Giorno R, Mallozzi M, Bozue J, Moody KS, Slack A, Qiu D, Wang R, Friedlander A, Welkos S, Driks A. Localization and assembly of proteins comprising the outer structures of the Bacillus anthracis spore. MICROBIOLOGY-SGM 2009; 155:1133-1145. [PMID: 19332815 DOI: 10.1099/mic.0.023333-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacterial spores possess a series of concentrically arranged protective structures that contribute to dormancy, survival and, ultimately, germination. One of these structures, the coat, is present in all spores. In Bacillus anthracis, however, the spore is surrounded by an additional, poorly understood, morphologically complex structure called the exosporium. Here, we characterize three previously discovered exosporium proteins called ExsFA (also known as BxpB), ExsFB (a highly related paralogue of exsFA/bxpB) and IunH (similar to an inosine-uridine-preferring nucleoside hydrolase). We show that in the absence of ExsFA/BxpB, the exosporium protein BclA accumulates asymmetrically to the forespore pole closest to the midpoint of the sporangium (i.e. the mother-cell-proximal pole of the forespore), instead of uniformly encircling the exosporium. ExsFA/BxpB may also have a role in coat assembly, as mutant spore surfaces lack ridges seen in wild-type spores and have a bumpy appearance. ExsFA/BxpB also has a modest but readily detected effect on germination. Nonetheless, an exsFA/bxpB mutant strain is fully virulent in both intramuscular and aerosol challenge models in Guinea pigs. We show that the pattern of localization of ExsFA/BxpB-GFP is a ring, consistent with a location for this protein in the basal layer of the exosporium. In contrast, ExsFB-GFP fluorescence is a solid oval, suggesting a distinct subcellular location for ExsFB-GFP. We also used these fusion proteins to monitor changes in the subcellular locations of these proteins during sporulation. Early in sporulation, both fusions were present throughout the mother cell cytoplasm. As sporulation progressed, GFP fluorescence moved from the mother cell cytoplasm to the forespore surface and formed either a ring of fluorescence, in the case of ExsFA/BxpB, or a solid oval of fluorescence, in the case of ExsFB. IunH-GFP also resulted in a solid oval of fluorescence. We suggest the interpretation that at least some ExsFB-GFP and IunH-GFP resides in the region between the coat and the exosporium, called the interspace.
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Affiliation(s)
- Rebecca Giorno
- Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, IL 60153, USA
| | - Michael Mallozzi
- Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, IL 60153, USA
| | - Joel Bozue
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Krishna-Sulayman Moody
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Alex Slack
- Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, IL 60153, USA
| | - Dengli Qiu
- Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Rong Wang
- Department of Biological, Chemical, and Physical Sciences, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Arthur Friedlander
- Headquarters, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Susan Welkos
- Bacteriology Division, United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD 21702-5011, USA
| | - Adam Driks
- Department of Microbiology and Immunology, Loyola University Medical Center, Maywood, IL 60153, USA
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Garcia-Verdugo I, Synguelakis M, Degrouard J, Franco CA, Valot B, Zivy M, Chaby R, Tanfin Z. Interaction of surfactant protein A with the intermediate filaments desmin and vimentin. Biochemistry 2008; 47:5127-38. [PMID: 18407667 DOI: 10.1021/bi800070u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Surfactant protein A (SP-A), a member of the collectin family that modulates innate immunity, has recently been involved in the physiology of reproduction. Consistent with the activation of ERK-1/2 and COX-2 induced by SP-A in myometrial cells, we reported previously the presence of two major proteins recognized by SP-A in these cells. Here we identify by mass spectrometry one of these SP-A targets as the intermediate filament (IF) desmin. In myometrial preparations derived from desmin-deficient mice, the absence of binding of SP-A to any 50 kDa protein confirmed the identity of this SP-A-binding site as desmin. Our data based on partial chymotrypsin digestion of pure desmin suggested that SP-A recognizes especially its rod domain, which is known to play an important role during the assembly of desmin into filaments. In line with that, electron microscopy experiments showed that SP-A inhibits in vitro the polymerization of desmin filaments. SP-A also recognized in vitro polymerized filaments in a calcium-dependent manner at a physiological ionic strength but not the C1q receptor gC1qR. Furthermore, Texas Red-labeled SP-A colocalized with desmin filaments in myometrial cells. Interestingly, vimentin, the IF characteristic of leukocytes, is one of the major proteins recognized by SP-A in protein extracts of U937 cells after PMA-induced differentiation of this monocytic cell line. Interaction of SP-A with vimentin was further confirmed using recombinant vimentin in solid-phase binding assays. The ability of SP-A to interact with desmin and vimentin, and to prevent polymerization of desmin monomers, shed light on unexpected and wider biological roles of this collectin.
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Affiliation(s)
- Ignacio Garcia-Verdugo
- Institut de Biochimie et Biophysique Moléculaire et Cellulaire, UMR-8619 du CNRS, Université de Paris-Sud, 91400 Orsay, France.
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Abstract
Adaptive immunity in jawless vertebrates (lamprey and hagfish) is mediated by lymphocytes that undergo combinatorial assembly of leucine-rich repeat (LRR) gene segments to create a diverse repertoire of variable lymphocyte receptor (VLR) genes. Immunization with particulate antigens induces VLR-B-bearing lymphocytes to secrete antigen-specific VLR-B antibodies. Here, we describe the production of recombinant VLR-B antibodies specific for BclA, a major coat protein of Bacillus anthracis spores. The recombinant VLR-B antibodies possess 8-10 uniform subunits that collectively bind antigen with high avidity. Sequence analysis, mutagenesis, and modeling studies show that antigen binding involves residues in the beta-sheets lining the VLR-B concave surface. EM visualization reveals tetrameric and pentameric molecules having a central core and highly flexible pairs of stalk-region "arms" with antigen-binding "hands." Remarkable antigen-binding specificity, avidity, and stability predict that these unusual LRR-based monoclonal antibodies will find many biomedical uses.
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The integrin Mac-1 (CR3) mediates internalization and directs Bacillus anthracis spores into professional phagocytes. Proc Natl Acad Sci U S A 2008; 105:1261-6. [PMID: 18216258 DOI: 10.1073/pnas.0709321105] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Anthrax, a disease caused by Bacillus anthracis, affects animals and humans. Because the inert spore is the infectious form of the organism that first contacts the potential host, the interaction between the host and spore exosporium is vital to the initiation of disease. Here, we demonstrate that the integrin Mac-1 is essential for the recognition of the major exosporium protein BclA by phagocytic cells. Expression of Mac-1, but not p150/95, in CHO cells markedly enhanced infection with Sterne strain of B. anthracis spores (WT spores). Conversely, CD11b(-/-) macrophages demonstrated a significant decrease in spore uptake when compared with macrophages from normal C57BL/6 mice. However, when CD11b(-/-) macrophages were infected with DeltabclA spores, spore ingestion was no different from their C57BL/6 counterparts. DeltabclA spores were also efficiently internalized by all CHO cell lines tested, independently of Mac-1 expression. Taken together, these results show that there is an alternative Mac-1-independent pathway involved in spore uptake that is unmasked only in the absence of BclA. Survival studies, using C57BL/6 and CD11b(-/-) mice, revealed that CD11b(-/-) mice are more resistant to infection with WT but not DeltabclA spores. Our experiments also show that DeltabclA spores are more virulent than WT spores in C57BL/6 and A/J mice. Overall, our data indicate that the Mac-1/BclA interaction may play a major role in B. anthracis pathogenesis by promoting spore uptake by professional phagocytes and subsequent access to a favorable niche for transport, germination, and outgrowth in lymphoid tissues.
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Liu CQ, Nuttall SD, Tran H, Wilkins M, Streltsov VA, Alderton MR. Construction, crystal structure and application of a recombinant protein that lacks the collagen-like region of BclA fromBacillus anthracis spores. Biotechnol Bioeng 2008; 99:774-82. [PMID: 17879302 DOI: 10.1002/bit.21637] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Spores of Bacillus anthracis, the causative agent of anthrax, are enclosed by an exosporium, which consists of a basal layer surrounded by a nap of hair-like filaments. The major structural component of the filaments is called BclA, which comprises a central collagen-like region (CLR) and a globular C-terminal domain. Here, the entire CLR coding sequence of BclA was removed, and the resulting protein (tBclA) produced in Escherichia coli. The crystallographic structure of tBclA was determined to 1.35 A resolution, and consists of an all-beta structure with a TNF-like jelly fold topology (12 beta-strands which form 2 beta-sheets of five strands each) consistent with previous studies on wild-type BclA. These globular domains are tightly packed into trimeric structures (surface shape complementarity; S (c) = 0.83), demonstrating that formation of the core structure of BclA is independent of the anchoring collagen-like region. A polyclonal antibody raised against tBclA recognized B. anthracis spores directly, and showed little cross-reactivity (<10%) with the spores of the closely related species Bacillus cereus and Bacillus thuringiensis, when compared to two other polyclonal antibodies raised against B. anthracis spore extracts and inactivated spores. The tBclA protein was used to purify a pool of specific antibodies from bovine colostrum whey samples from cows inoculated with the Sterne strain anthrax vaccine, which also showed reactivity with B. anthracis spores. Together, these results demonstrate that tBclA provides a safer and more effective way to the production and purification of antibodies with high binding affinity for B. anthracis spores. Biotechnol. Bioeng. 2008;99: 774-782. (c) 2007 Wiley Periodicals, Inc.
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Affiliation(s)
- Chun-Qiang Liu
- DSTO Human Protection & Performance Division, 506 Lorimer Street, Fishermans Bend, Melbourne, Victoria 3207, Australia.
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Abstract
Endospores formed by Bacillus, Clostridia, and related genera are encased in a protein shell called the coat. In many species, including B. subtilis, the coat is the outermost spore structure, and in other species, such as the pathogenic organisms B. anthracis and B. cereus, the spore is encased in an additional layer called the exosporium. Both the coat and the exosporium have roles in protection of the spore and in its environmental interactions. Assembly of both structures is a function of the mother cell, one of two cellular compartments of the developing sporangium. Studies in B. subtilis have revealed that the timing of coat protein production, the guiding role of a small group of morphogenetic proteins, and several types of posttranslational modifications are essential for the fidelity of the assembly process. Assembly of the exosporium requires a set of novel proteins as well as homologues of proteins found in the outermost layers of the coat and of some of the coat morphogenetic factors, suggesting that the exosporium is a more specialized structure of a multifunctional coat. These and other insights into the molecular details of spore surface morphogenesis provide avenues for exploitation of the spore surface layers in applications for biotechnology and medicine.
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Affiliation(s)
- Adriano O Henriques
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras Codex, Portugal.
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Ghebrehiwet B, Tantral L, Titmus MA, Panessa-Warren BJ, Tortora GT, Wong SS, Warren JB. The exosporium of B. cereus contains a binding site for gC1qR/p33: implication in spore attachment and/or entry. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 598:181-97. [PMID: 17892212 PMCID: PMC2630858 DOI: 10.1007/978-0-387-71767-8_13] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
B. cereus, is a member of a genus of aerobic, gram-positive, spore-forming rod-like bacilli, which includes the deadly, B. anthracis. Preliminary experiments have shown that gC1qR binds to B. cereus spores that have been attached to microtiter plates. The present studies were therefore undertaken, to examine if cell surface gC1qR plays a role in B. cereus spore attachment and/or entry. Monolayers of human colon carcinoma (Caco-2) and lung cells were grown to confluency on 6 mm coverslips in shell vials with gentle swirling in a shaker incubator. Then, 2 microl of a suspension of strain SB460 B. cereus spores (3x10(8)/ml, in sterile water), were added and incubated (1-4 h; 36 degrees C) in the presence or absence of anti-gC1qR mAb-carbon nanoloops. Examination of these cells by EM revealed that: (1) When B. cereus endospores contacted the apical Caco-2 cell surface, or lung cells, gC1qR was simultaneously detectable, indicating upregulation of the molecule. (2) In areas showing spore contact with the cell surface, gC1qR expression was often adjacent to the spores in association with microvilli (Caco-2 cells) or cytoskeletal projections (lung cells). (3) Furthermore, the exosporia of the activated and germinating spores were often decorated with mAb-nanoloops. These observations were further corroborated by experiments in which B.cereus spores were readily taken up by monocytes and neutrophils, and this uptake was partially inhibited by mAb 60.11, which recognizes the C1q binding site on gC1qR. Taken together, the data suggest a role, for gC1qR at least in the initial stages of spore attachment and/or entry.
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Walker JR, Gnanam AJ, Blinkova AL, Hermandson MJ, Karymov MA, Lyubchenko YL, Graves PR, Haystead TA, Linse KD. Clostridium taeniosporum spore ribbon-like appendage structure, composition and genes. Mol Microbiol 2007; 63:629-43. [PMID: 17302797 DOI: 10.1111/j.1365-2958.2006.05494.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Clostridium taeniosporum spores have about 12 large, flat, ribbon-like appendages attached through a common trunk at one spore pole to a previously unknown surface layer outside the coat that is proposed to be called the 'encasement'. Appendages are about 4.5 microm long, 0.5 microm wide and 30 nm thick and taper at the attachment end into a semicircle that is twisted relative to the flat ribbon. Individual fibrils, about 45 nm in length with spherical heads and long thin tails, form a hair-like nap, visible along the appendage edge. Four appendage proteins have been detected: a paralogous pair of 29 kDa (designated P29a and P29b), a glycoprotein of about 37 kDa (designated GP85) and an orthologue of the Bacillus spore morphogenetic protein SpoVM. The P29 proteins consist of duplicated regions and each region includes a domain of unknown function 11. The GP85 glycoprotein contains a collagen-like region. The genes for P29a and b, GP85 and possibly related proteins are closely linked on two small chromosome fragments. Putative sigma(K)-dependent promoters upstream of the P29a and b genes indicate that they likely are expressed late in the mother cell, consistent with their deposition into the layer external to the coat.
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Affiliation(s)
- James R Walker
- Molecular Genetics and Microbiology Section and Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712, USA.
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Ghai R, Waters P, Roumenina LT, Gadjeva M, Kojouharova MS, Reid KBM, Sim RB, Kishore U. C1q and its growing family. Immunobiology 2007; 212:253-66. [PMID: 17544811 DOI: 10.1016/j.imbio.2006.11.001] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 11/01/2006] [Indexed: 11/18/2022]
Abstract
C1q is the target recognition protein of the classical complement pathway and a major connecting link between innate and acquired immunity. As a charge pattern recognition molecule of innate immunity, C1q can engage a broad range of self and non-self ligands via its heterotrimeric globular (gC1q) domain and thus trigger the classical pathway. The trimeric gC1q signature domain has been identified in a variety of non-complement proteins that can be grouped together as a C1q family. The X-ray crystal structures of the gC1q domain of a few members of the C1q family reveal a compact jelly-roll beta-sandwich fold similar to that of the multifunctional tumor necrosis factor (TNF) ligand family, hence the C1q and TNF superfamily. This review is an update on the structural and functional aspects of the gC1q domain of human C1q. We also mention the diverse range of proteins that utilize a gC1q domain in order to reflect on its importance as a versatile scaffold to support a variety of functions.
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Affiliation(s)
- Rohit Ghai
- Institute of Medical Microbiology, Justus-Liebig-University, Frankfurter Strasse 107, 35392 Giessen, Germany
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Grivennikov SI, Kuprash DV, Liu ZG, Nedospasov SA. Intracellular signals and events activated by cytokines of the tumor necrosis factor superfamily: From simple paradigms to complex mechanisms. ACTA ACUST UNITED AC 2007; 252:129-61. [PMID: 16984817 DOI: 10.1016/s0074-7696(06)52002-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tumor necrosis factor (TNF) and several related cytokines can induce opposite effects such as cell activation and proliferation or cell death. How the cell maintains the balance between these seemingly mutually exclusive pathways has long remained a mystery. TNF receptor I (TNFRI) initially emerged as a potent activator of NFkappaB and AP-1 transcription factors, while the related CD95 (Fas, Apo-1) was recognized as a prototype death receptor. Advances in research have uncovered critical molecular players in these intracellular processes. They have also revealed a much more complex picture than originally thought. Several new signaling pathways, including the alternative NFkappaB activation cascade, have been uncovered, and previously unknown modes of cross-talk between intracellular signaling molecules were revealed. It also turned out that signaling mechanisms mediated by the TNF receptor superfamily members can operate not only in the immune system but also in organ development.
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Affiliation(s)
- Sergei I Grivennikov
- Laboratory of Molecular Immunology, Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 119991 Moscow, Russia
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Peerschke EIB, Ghebrehiwet B. The contribution of gC1qR/p33 in infection and inflammation. Immunobiology 2007; 212:333-42. [PMID: 17544818 PMCID: PMC2001281 DOI: 10.1016/j.imbio.2006.11.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 11/21/2006] [Accepted: 11/27/2006] [Indexed: 12/24/2022]
Abstract
Human gC1qR/p33 is a multi-compartmental and multi-functional cellular protein expressed on a wide range of tissues and cell types including lymphocytes, endothelial cells, dendritic cells, and platelets. Although originally isolated as a receptor for C1q by virtue of its affinity (K(d)=15-50 nM), and specificity for the globular heads of this molecule, a large body of evidence has now been accumulated which shows that in addition to C1q, gC1qR can serve as a receptor for diverse proinflammatory ligands including proteins of the plasma kinin-forming system, most notably high molecular weight kininogen (HK; K(d)=9 nM). In addition, gC1qR has been reported to recognize and bind a number of functional antigens of viral and bacterial origin. It is its ability to interact with microbial antigens and its potential to serve as a cellular protein for bacterial attachment and/or entry that has been the focus of our laboratory in the past few years. On the surface of activated platelets, gC1qR has been shown to serve as a binding site for Staphylococcus aureus and this binding is mediated by protein A. Since the binding of S. aureus to platelets is postulated to play a major role in the pathogenesis of endocarditis, gC1qR may provide a suitable surface for the initial adhesion of the bacterium. Recent data also demonstrate that the exosporium of Bacillus cereus, a member of a genus of aerobic, Gram-positive, spore-forming rod-like bacilli, which includes the deadly Bacillus anthracis, contains a binding site for gC1qR. Therefore, by virtue of its ability to recognize plasma proteins such as C1q and HK, as well as bacterial and viral antigens, cell-surface gC1qR not only is able to generate proinflammatory byproducts from the complement and kinin/kallikrein systems, but also can be an efficient vehicle and platform for a plethora of pathogenic microorganisms.
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Affiliation(s)
- Ellinor I B Peerschke
- Department of Pathology, Weill Medical College of Cornell University, New York Presbyterian Hospital, 525 East 68th Street, Room F715, NY 10021, USA.
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