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Miao C, Cui Y, Yan Z, Jiang Y. Pilus of Streptococcus pneumoniae: structure, function and vaccine potential. Front Cell Infect Microbiol 2023; 13:1270848. [PMID: 37799336 PMCID: PMC10548224 DOI: 10.3389/fcimb.2023.1270848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/04/2023] [Indexed: 10/07/2023] Open
Abstract
The pilus is an extracellular structural part that can be detected in some Streptococcus pneumoniae (S. pneumoniae) isolates (type I pili are found in approximately 30% of strains, while type II pili are found in approximately 20%). It is anchored to the cell wall by LPXTG-like motifs on the peptidoglycan. Two kinds of pili have been discovered, namely, pilus-1 and pilus-2. The former is encoded by pilus islet 1 (PI-1) and is a polymer formed by the protein subunits RrgA, RrgB and RrgC. The latter is encoded by pilus islet 2 (PI-2) and is a polymer composed mainly of the structural protein PitB. Although pili are not necessary for the survival of S. pneumoniae, they serve as the structural basis and as virulence factors that mediate the adhesion of bacteria to host cells and play a direct role in promoting the adhesion, colonization and pathogenesis of S. pneumoniae. In addition, as candidate antigens for protein vaccines, pili have promising potential for use in vaccines with combined immunization strategies. Given the current understanding of the pili of S. pneumoniae regarding the genes, proteins, structure, biological function and epidemiological relationship with serotypes, combined with the immunoprotective efficacy of pilins as protein candidates for vaccines, we here systematically describe the research status and prospects of S. pneumoniae pili and provide new ideas for subsequent vaccine research and development.
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Affiliation(s)
- Chenglin Miao
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yali Cui
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Laboratory Medicine, Meishan Women and Children’s Hospital, Alliance Hospital of West China Second University Hospital, Sichuan University, Meishan, Sichuan, China
- Department of Laboratory Medicine, West China Second University Hospital (Tianfu), Sichuan University/Sichuan Provincial Children’s Hospital, Meishan, Sichuan, China
| | - Ziyi Yan
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yongmei Jiang
- Department of Laboratory Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, Sichuan, China
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2
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Takahashi C, Sato M, Sato C. Biofilm formation of Staphylococcus epidermidis imaged using atmospheric scanning electron microscopy. Anal Bioanal Chem 2021; 413:7549-7558. [PMID: 34671824 DOI: 10.1007/s00216-021-03720-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 09/01/2021] [Accepted: 10/05/2021] [Indexed: 11/30/2022]
Abstract
Staphylococcus epidermidis are gram-positive bacteria that form a biofilm around implanted devices and develop an infection into a chronic state. Recently, it has been revealed that microvesicles have important roles in biofilm formation and intercellular communication among bacteria. However, biofilm formation of Staphylococcus epidermidis, and its relation to microvesicle secretion, is poorly understood because of the difficulty required to preserve the delicate water-rich morphology of biofilm for high-resolution observations. Here, we successfully imaged the microvesicles secreted from Staphylococcus epidermidis and the subsequent process of their integration into biofilm using liquid-phase imaging using atmospheric scanning electron microscopy (ASEM). In the biofilm, cells were connected by nanotube-like structures attached by microvesicles, and surrounded by extracellular polymeric substances. Cells cultured in the ASEM specimen holder were aldehyde-fixed and stained using positively charged nanogold labelling and/or using National Center for Microscopy and Imaging Research method. The samples immersed in aqueous radical scavenger glucose buffer were imaged by the inverted SEM of ASEM. Information regarding the morphologies of microvesicles, nanotube-like fibrils, and biofilm formed by Staphylococcus epidermidis is expected to be useful to elucidate the biological mechanism of biofilm formation and to develop a medicine against biofilms and their associated infections.
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Affiliation(s)
- Chisato Takahashi
- Department of Materials and Chemistry, National Institute of Advanced Industrial Science and Technology, 2266-98, Anagahora, Shimoshidami, Moriyama-ku, Nagoya, Aichi, 463-8560, Japan.
| | - Mari Sato
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8568, Japan
| | - Chikara Sato
- Health and Medical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki, 305-8568, Japan
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3
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Acebo P, Herranz C, Espenberger LB, Gómez-Sanz A, Terrón MC, Luque D, Amblar M. A Small Non-Coding RNA Modulates Expression of Pilus-1 Type in Streptococcus pneumoniae. Microorganisms 2021; 9:microorganisms9091883. [PMID: 34576778 PMCID: PMC8465756 DOI: 10.3390/microorganisms9091883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022] Open
Abstract
Streptococcus pneumoniae is a major cause of morbidity and mortality worldwide, and about 30% of the pneumococcal clinical isolates show type I pili-like structures. These long proteinaceous polymers extending from the bacterial surface are encoded by pilus islet 1 and play major roles in adhesion and host colonization. Pili expression is bistable and is controlled by the transcriptional activator RlrA. In this work, we demonstrate that the previously identified small noncoding RNA srn135 also participates in pilus regulation. Our findings show that srn135 is generated upon processing of the 5′-UTR region of rrgA messenger and its deletion prevents the synthesis of RrgA, the main pili adhesin. Moreover, overexpression of srn135 increases the expression of all pili genes and rises the percentage of piliated bacteria within a clonal population. This regulation is mediated by the stabilization of rlrA mRNA since higher levels of srn135 increase its half-life to 165%. Our findings suggest that srn135 has a dual role in pilus expression acting both in cis- (on the RrgA levels) and in trans- (modulating the levels of RlrA) and contributes to the delicate balance between pili expressing and non-expressing bacteria.
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Affiliation(s)
- Paloma Acebo
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (P.A.); (C.H.); (L.B.E.); (A.G.-S.)
| | - Cristina Herranz
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (P.A.); (C.H.); (L.B.E.); (A.G.-S.)
| | - Lucas Bernal Espenberger
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (P.A.); (C.H.); (L.B.E.); (A.G.-S.)
| | - Alicia Gómez-Sanz
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (P.A.); (C.H.); (L.B.E.); (A.G.-S.)
| | - María Carmen Terrón
- Unidad de Microscopia Electrónica y Confocal, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (M.C.T.); (D.L.)
| | - Daniel Luque
- Unidad de Microscopia Electrónica y Confocal, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (M.C.T.); (D.L.)
| | - Mónica Amblar
- Unidad de Patología Molecular del Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (P.A.); (C.H.); (L.B.E.); (A.G.-S.)
- Correspondence:
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4
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Prajapati A, Palva A, von Ossowski I, Krishnan V. LrpCBA pilus proteins of gut-dwelling Ligilactobacillus ruminis: crystallization and X-ray diffraction analysis. Acta Crystallogr F Struct Biol Commun 2021; 77:238-245. [PMID: 34341189 PMCID: PMC8329715 DOI: 10.1107/s2053230x21007263] [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: 06/15/2021] [Accepted: 07/13/2021] [Indexed: 11/10/2022] Open
Abstract
Adhesion to host surfaces for bacterial survival and colonization involves a variety of molecular mechanisms. Ligilactobacillus ruminis, a strict anaerobe and gut autochthonous (indigenous) commensal, relies on sortase-dependent pili (LrpCBA) for adherence to the intestinal inner walls, thereby withstanding luminal content flow. Here, the LrpCBA pilus is a promiscuous binder to gut collagen, fibronectin and epithelial cells. Structurally, the LrpCBA pilus displays a representative hetero-oligomeric arrangement and consists of three types of pilin subunit, each with its own location and function, i.e. tip LrpC for adhesion, basal LrpB for anchoring and backbone LrpA for length. To provide further structural insights into the assembly, anchoring and functional mechanisms of sortase-dependent pili, each of the L. ruminis pilus proteins was produced recombinantly for crystallization and X-ray diffraction analysis. Crystals of LrpC, LrpB, LrpA and truncated LrpA generated by limited proteolysis were obtained and diffracted to resolutions of 3.0, 1.5, 2.2 and 1.4 Å, respectively. Anomalous data were also collected from crystals of selenomethionine-substituted LrpC and an iodide derivative of truncated LrpA. Successful strategies for protein production, crystallization and derivatization are reported.
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Affiliation(s)
- Amar Prajapati
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad 121 001, India
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | | | - Vengadesan Krishnan
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad 121 001, India
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Exploiting pilus-mediated bacteria-host interactions for health benefits. Mol Aspects Med 2021; 81:100998. [PMID: 34294411 DOI: 10.1016/j.mam.2021.100998] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/30/2021] [Accepted: 07/16/2021] [Indexed: 02/06/2023]
Abstract
Surface pili (or fimbriae) are an important but conspicuous adaptation of several genera and species of Gram-negative and Gram-positive bacteria. These long and non-flagellar multi-subunit adhesins mediate the initial contact that a bacterium has with a host or environment, and thus have come to be regarded as a key colonization factor for virulence activity in pathogens or niche adaptation in commensals. Pili in pathogenic bacteria are well recognized for their roles in the adhesion to host cells, colonization of tissues, and establishment of infection. As an 'anti-adhesive' ploy, targeting pilus-mediated attachment for disruption has become a potentially effective alternative to using antibiotics. In this review, we give a description of the several structurally distinct bacterial pilus types thus far characterized, and as well offer details about the intricacy of their individual structure, assembly, and function. With a molecular understanding of pilus biogenesis and pilus-mediated host interactions also provided, we go on to describe some of the emerging new approaches and compounds that have been recently developed to prevent the adhesion, colonization, and infection of piliated bacterial pathogens.
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6
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Sortase-assembled pili in Corynebacterium diphtheriae are built using a latch mechanism. Proc Natl Acad Sci U S A 2021; 118:2019649118. [PMID: 33723052 DOI: 10.1073/pnas.2019649118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Gram-positive bacteria assemble pili (fimbriae) on their surfaces to adhere to host tissues and to promote polymicrobial interactions. These hair-like structures, although very thin (1 to 5 nm), exhibit impressive tensile strengths because their protein components (pilins) are covalently crosslinked together via lysine-isopeptide bonds by pilus-specific sortase enzymes. While atomic structures of isolated pilins have been determined, how they are joined together by sortases and how these interpilin crosslinks stabilize pilus structure are poorly understood. Using a reconstituted pilus assembly system and hybrid structural biology methods, we elucidated the solution structure and dynamics of the crosslinked interface that is repeated to build the prototypical SpaA pilus from Corynebacterium diphtheriae We show that sortase-catalyzed introduction of a K190-T494 isopeptide bond between adjacent SpaA pilins causes them to form a rigid interface in which the LPLTG sorting signal is inserted into a large binding groove. Cellular and quantitative kinetic measurements of the crosslinking reaction shed light onto the mechanism of pilus biogenesis. We propose that the pilus-specific sortase in C. diphtheriae uses a latch mechanism to select K190 on SpaA for crosslinking in which the sorting signal is partially transferred from the enzyme to a binding groove in SpaA in order to facilitate catalysis. This process is facilitated by a conserved loop in SpaA, which after crosslinking forms a stabilizing latch that covers the K190-T494 isopeptide bond. General features of the structure and sortase-catalyzed assembly mechanism of the SpaA pilus are likely conserved in Gram-positive bacteria.
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7
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Ness S, Hilleringmann M. Streptococcus pneumoniae Type 1 Pilus - A Multifunctional Tool for Optimized Host Interaction. Front Microbiol 2021; 12:615924. [PMID: 33633703 PMCID: PMC7899983 DOI: 10.3389/fmicb.2021.615924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/20/2021] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae represents a major Gram-positive human pathogen causing bacterial pneumonia, otitis media, meningitis, and other invasive diseases. Several pneumococcal isolates show increasing resistance rates against antibacterial agents. A variety of virulence factors promote pneumococcal pathogenicity with varying importance in different stages of host infection. Virulence related hair-like structures ("pili") are complex, surface located protein arrays supporting proper host interaction. In the last two decades different types of pneumococcal pili have been identified: pilus-1 (P1) and pilus-2 (P2) are formed by the catalytic activity of sortases that covalently assemble secreted polypeptide pilin subunits in a defined order and finally anchor the resulting pilus in the peptidoglycan. Within the long pilus fiber the presence of intramolecular isopeptide bonds confer high stability to the sequentially arranged individual pilins. This mini review will focus on S. pneumoniae TIGR4 P1 molecular architecture, the subunits it builds and provides insights into P1 sortase-mediated assembly. The complex P1 architecture (anchor-/backbone-/tip-subunits) allows the specific interaction with various target structures facilitating different steps of colonization, invasion and spreading within the host. Optimized pilin subunit confirmation supports P1 function under physiological conditions. Finally, aspects of P1- host interplay are summarized, including recent insights into P1 mechanobiology, which have important implications for P1 mediated pathogenesis.
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Affiliation(s)
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Munich, Germany
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Megta AK, Pratap S, Kant A, Palva A, von Ossowski I, Krishnan V. Crystal structure of the atypically adhesive SpaB basal pilus subunit: Mechanistic insights about its incorporation in lactobacillar SpaCBA pili. Curr Res Struct Biol 2020; 2:229-238. [PMID: 34235482 PMCID: PMC8244301 DOI: 10.1016/j.crstbi.2020.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/04/2020] [Accepted: 11/06/2020] [Indexed: 02/07/2023] Open
Abstract
To successfully colonize a host or environment, certain genera and species of Gram-positive bacteria have evolved to utilize the so-called sortase-dependent pilus, a long multi-subunit and non-flagellar surface adhesin. One example of this is Lactobacillus rhamnosus GG, a gut-adapted probiotic strain that produces SpaCBA pili. These structures are covalent hetero-oligomers built from three types of pilin subunit, each with a specific location and function (i.e., backbone SpaA for length, tip SpaC for adhesion, and basal SpaB for anchoring). Functionally, the SpaCBA pilus exhibits a promiscuous affinity for components on intestinal surfaces (e.g., mucus, collagen, and epithelial cells), which is largely attributed to the SpaC subunit. Then again, the basal SpaB pilin, in addition to acting as the terminal subunit during pilus assembly, displays an out of character mucoadhesive function. To address the structural basis of this unusual dual functionality, we reveal the 2.39 Å resolution crystal structure of SpaB. SpaB consists of one immunoglobulin-like CnaB domain and contains a putative intermolecular isopeptide bond-linking lysine and internal isopeptide bond-asparagine in an FPKN pilin motif within the C-terminal end. Remarkably, we found that a C-terminal stretch of positively charged lysine and arginine residues likely accounts for the atypical mucoadhesiveness of SpaB. Although harboring an autocatalytic triad of residues for a potential internal isopeptide interaction, the SpaB crystal structure lacked the visible electron density for intact bond formation, yet its presence was subsequently confirmed by mass spectral analysis. Finally, we propose a structural model that captures the exclusive basal positioning of SpaB in the SpaCBA pilus.
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Key Words
- ABC, ammonium bicarbonate
- ACN, acetonitrile
- Cell-wall anchoring
- Cna, collagen adhesin
- ECM, extracellular matrix
- Ig, immunoglobulin
- Lactobacillus rhamnosus GG
- MD, molecular dynamics
- MS, mass spectrometry
- Mucus adhesion
- PDB, Protein Data Bank
- PEG, polyethylene glycol
- Probiotic
- Sortase-dependent SpaCBA pili
- SpaB basal pilin
- rmsd, root mean square deviation
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Affiliation(s)
- Abhin Kumar Megta
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India.,School of Biotechnology, KIIT University, Odisha, 751024, India
| | - Shivendra Pratap
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Abhiruchi Kant
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India.,Department of Biotechnology, Manipal University, Karnataka, 576104, India
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, FIN-00014, Finland
| | - Ingemar von Ossowski
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, FIN-00014, Finland
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
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Deciphering Streptococcal Biofilms. Microorganisms 2020; 8:microorganisms8111835. [PMID: 33233415 PMCID: PMC7700319 DOI: 10.3390/microorganisms8111835] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 11/10/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Streptococci are a diverse group of bacteria, which are mostly commensals but also cause a considerable proportion of life-threatening infections. They colonize many different host niches such as the oral cavity, the respiratory, gastrointestinal, and urogenital tract. While these host compartments impose different environmental conditions, many streptococci form biofilms on mucosal membranes facilitating their prolonged survival. In response to environmental conditions or stimuli, bacteria experience profound physiologic and metabolic changes during biofilm formation. While investigating bacterial cells under planktonic and biofilm conditions, various genes have been identified that are important for the initial step of biofilm formation. Expression patterns of these genes during the transition from planktonic to biofilm growth suggest a highly regulated and complex process. Biofilms as a bacterial survival strategy allow evasion of host immunity and protection against antibiotic therapy. However, the exact mechanisms by which biofilm-associated bacteria cause disease are poorly understood. Therefore, advanced molecular techniques are employed to identify gene(s) or protein(s) as targets for the development of antibiofilm therapeutic approaches. We review our current understanding of biofilm formation in different streptococci and how biofilm production may alter virulence-associated characteristics of these species. In addition, we have summarized the role of surface proteins especially pili proteins in biofilm formation. This review will provide an overview of strategies which may be exploited for developing novel approaches against biofilm-related streptococcal infections.
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Iovino F, Nannapaneni P, Henriques-Normark B, Normark S. The impact of the ancillary pilus-1 protein RrgA of Streptococcus pneumoniae on colonization and disease. Mol Microbiol 2020; 113:650-658. [PMID: 32185835 DOI: 10.1111/mmi.14451] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 12/11/2022]
Abstract
The Gram-positive bacterium Streptococcus pneumoniae, the pneumococcus, is an important commensal resident of the human nasopharynx. Carriage is usually asymptomatic, however, S. pneumoniae can become invasive and spread from the upper respiratory tract to the lungs causing pneumonia, and to other organs to cause severe diseases such as bacteremia and meningitis. Several pneumococcal proteins important for its disease-causing capability have been described and many are expressed on the bacterial surface. The surface located pneumococcal type-1 pilus has been associated with virulence and the inflammatory response, and it is present in 20%-30% of clinical isolates. Its tip protein RrgA has been shown to be a major adhesin to human cells and to promote invasion through the blood-brain barrier. In this review we discuss recent findings of the impact of RrgA on bacterial colonization of the upper respiratory tract and on pneumococcal virulence, and use epidemiological data and genome-mining to suggest trade-off mechanisms potentially explaining the rather low prevalence of pilus-1 expressing pneumococci in humans.
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Affiliation(s)
- Federico Iovino
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Priyanka Nannapaneni
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Birgitta Henriques-Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and Lee Kong Chian School of Medicine (LKC), Nanyang Technological University (NTU), Singapore, Singapore
| | - Staffan Normark
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and Lee Kong Chian School of Medicine (LKC), Nanyang Technological University (NTU), Singapore, Singapore
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Kant A, Palva A, von Ossowski I, Krishnan V. Crystal structure of lactobacillar SpaC reveals an atypical five-domain pilus tip adhesin: Exposing its substrate-binding and assembly in SpaCBA pili. J Struct Biol 2020; 211:107571. [PMID: 32653644 DOI: 10.1016/j.jsb.2020.107571] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/23/2020] [Accepted: 07/02/2020] [Indexed: 12/11/2022]
Abstract
Adhesion to cell surfaces is an essential and early prerequisite for successful host colonization by bacteria, and in most instances involves the specificities of various adhesins. Among bacterial Gram-positives, some genera and species mediate attachment to host cells by using long non-flagellar appendages called sortase-dependent pili. A case in point is the beneficial Lactobacillus rhamnosus GG gut-adapted strain that produces the so-called SpaCBA pilus, a structure noted for its promiscuous binding to intestinal mucus and collagen. Structurally, SpaCBA pili are heteropolymers of three different pilin-protein subunits, each with its own location and function in the pilus: backbone SpaA for length, basal SpaB for anchoring, and tip SpaC for adhesion. Previously, we solved the SpaA tertiary structure by X-ray crystallography and also reported on the crystallization of SpaB and SpaC. Here, we reveal the full-length high-resolution (1.9 Å) crystal structure of SpaC, a first for a sortase-dependent pilus-bearing commensal. The SpaC structure, unlike the representative four-domain architecture of other Gram-positive tip pilins, espouses an atypically longer five-domain arrangement that includes N-terminal 'binding' and C-terminal 'stalk' regions of two and three domains, respectively. With the prospect of establishing new mechanistic insights, we provide a structural basis for the multi-substrate binding nature of SpaC, as well as a structural model that reconciles its exclusive localization at the SpaCBA pilus tip.
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Affiliation(s)
- Abhiruchi Kant
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad 122016, India; Department of Biotechnology, Manipal University, Karnataka 576104, India
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki FIN-00014, Finland
| | - Ingemar von Ossowski
- Department of Veterinary Biosciences, University of Helsinki, Helsinki FIN-00014, Finland
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad 122016, India.
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Kumar Megta A, Palva A, von Ossowski I, Krishnan V. SpaB, an atypically adhesive basal pilin from the lactobacillar SpaCBA pilus: crystallization and X-ray diffraction analysis. Acta Crystallogr F Struct Biol Commun 2019; 75:731-737. [PMID: 31797814 PMCID: PMC6891582 DOI: 10.1107/s2053230x19015358] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 11/13/2019] [Indexed: 02/06/2023] Open
Abstract
The SpaB pilin is recognized as the basal subunit of the sortase-dependent SpaCBA pilus, which is known to be produced by the Gram-positive Lactobacillus rhamnosus GG, a gut-adapted commensal advocated to have health benefits. Despite seeming to function as an archetypal basal pilin by serving as the terminal subunit in pilus assembly, SpaB also assumes an atypical role as a mucoadhesive protein. To shed light on the structural factors that contribute to this dual functional behaviour, a recombinant form of the L. rhamnosus GG SpaB pilin was produced and purified for crystallization and X-ray diffraction experiments. The crystallization of SpaB remained particularly challenging until the implementation of a three-pronged crystallization approach involving C-terminal tail truncation, surface lysine methylation and magnesium additives. Ultimately, hexagonal crystals of SpaB were produced and were able to diffract to a resolution of 2.4 Å. This crystal form belonged to space group P6522 or P6122, with unit-cell parameters a = b = 51.53, c = 408.22 Å, α = β = 90.0, γ = 120.0°. Obtaining an interpretable electron-density map via single-wavelength anomalous diffraction (SAD) using iodide-derivative data sets did not succeed owing to the weak anomalous signal. As an alternative, attempts to provide phases by molecular replacement using the iodide-SAD data from SpaB and a collection of distant homology models (<28% sequence identity) are in progress.
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Affiliation(s)
- Abhin Kumar Megta
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana 121 001, India
- School of Biotechnology, KIIT University, Odisha 751 024, India
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | | | - Vengadesan Krishnan
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana 121 001, India
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Polzer C, Ness S, Mohseni M, Kellerer T, Hilleringmann M, Rädler J, Hellerer T. Correlative two-color two-photon (2C2P) excitation STED microscopy. BIOMEDICAL OPTICS EXPRESS 2019; 10:4516-4530. [PMID: 31565507 PMCID: PMC6757464 DOI: 10.1364/boe.10.004516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 06/10/2023]
Abstract
We present a two-color two-photon stimulated emission depletion microscopy technique (2C2P-STED) that correlates a confocal image with a super-resolved image employing the inherent self-referencing mechanism of nonlinear excitation. The novel approach overcomes the substantial challenge posed by two different imaging modalities in laser-scanning fluorescence microscopy for colocalization on the nanometer scale. Demonstrating the principle of 2C2P-STED, we show for the first time super-resolved images of the gram-positive bacteria Streptococcus pneumoniae TIGR4 pilus type-1. A signal-to-noise ratio (SNR) greater than 10 was achieved in 2C2P excitation mode and approximately 70 nm details were resolved in 2P-STED.
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Affiliation(s)
- Christoph Polzer
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
- Faculty of Physics, Soft Condensed Matter, Ludwig-Maximilians-University, 80539 Munich, Germany
| | - Stefan Ness
- FG Protein Biochemistry & Cellular Microbiology, University of Applied Sciences Munich, 80335 Munich, Germany
| | - Mojtaba Mohseni
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
| | - Thomas Kellerer
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, University of Applied Sciences Munich, 80335 Munich, Germany
| | - Joachim Rädler
- Faculty of Physics, Soft Condensed Matter, Ludwig-Maximilians-University, 80539 Munich, Germany
| | - Thomas Hellerer
- Multiphoton Imaging Lab, Munich University of Applied Sciences, 80335 Munich, Germany
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14
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Becke TD, Ness S, Kaufmann BK, Hartmann B, Schilling AF, Sudhop S, Hilleringmann M, Clausen-Schaumann H. Pilus-1 Backbone Protein RrgB of Streptococcus pneumoniae Binds Collagen I in a Force-Dependent Way. ACS NANO 2019; 13:7155-7165. [PMID: 31184856 DOI: 10.1021/acsnano.9b02587] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Attachment to host tissue is a prerequisite for successful host colonization and invasion of pathogens. Many pathogenic bacteria use surface appendices, called pili, to bind and firmly attach to host tissue surfaces. Although it has been speculated that the laterally positioned D3 domain of the pilus-1 backbone protein RrgB of Streptococcus pneumoniae may promote bacterial-host interaction, via adhesion to extracellular matrix molecules, such as collagen, earlier studies showed no affinity of RrgB to collagen I. Using atomic force microscopy-based single molecule force spectroscopy combined with lateral force microscopy, we show that under mechanical load, RrgB in fact binds to human collagen I in a force-dependent manner. We observe exceptionally strong interactions, with interaction forces reaching as much as 1500 pN, and we show that high force loading and shearing rates enhance and further strengthen the interaction. In addition, the affinity of RrgB to collagen I under mechanical load not only depends on the orientation of the D3 domain but also on the orientation of the collagen fibrils, relative to the pulling direction. Both exceptionally high binding forces and force-induced bond strengthening resemble the behavior of so-called catch bonds, which have recently been observed in bacterial adhesins, but have not been reported for multimeric backbone subunits of virulence related pili.
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Affiliation(s)
- Tanja D Becke
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Stefan Ness
- FG Protein Biochemistry and Cellular Microbiology , Munich University of Applied Sciences , 80335 Munich , Germany
| | - Benedikt K Kaufmann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Bastian Hartmann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Arndt F Schilling
- Clinic for Trauma Surgery, Orthopaedics, and Plastic Surgery , University Medical Center Göttingen , 37075 Göttingen , Germany
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
| | - Markus Hilleringmann
- FG Protein Biochemistry and Cellular Microbiology , Munich University of Applied Sciences , 80335 Munich , Germany
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine , Munich University of Applied Sciences , 80335 Munich , Germany
- Center for NanoScience , Ludwig-Maximilians-Universität München , 80799 Munich , Germany
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15
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Megta AK, Mishra AK, Palva A, von Ossowski I, Krishnan V. Crystal structure of basal pilin SpaE reveals the molecular basis of its incorporation in the lactobacillar SpaFED pilus. J Struct Biol 2019; 207:74-84. [PMID: 31026587 DOI: 10.1016/j.jsb.2019.04.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/15/2019] [Accepted: 04/23/2019] [Indexed: 11/16/2022]
Abstract
For some Gram-positive genera and species, the long-extended and adhesive sortase-dependent pilus plays an essential role during host colonization, biofilm formation, and immune modulation. Lactobacillus rhamnosus GG is a gut-adapted commensal strain that harbors the operonic genes for the SpaCBA and SpaFED pili, both being comprised of three different protein subunits termed the backbone, tip, and basal pilins. Crystal structures of the backbone pilins (SpaA and SpaD) have recently been solved, and here we describe the high-resolution (1.5 Å) structural determination of the SpaE basal pilin. SpaE consists of two immunoglobulin-like CnaB domains, with each displaying a spontaneously formed internal isopeptide bond, though apparently slow forming in the N-terminal domain. Remarkably, SpaE contains an atypically lengthy unstructured C-terminal tail, along with an YPKN pilin motif peptide, which is normally reserved for backbone subunits. Based on our analysis of the crystal structure data, we provide a molecular model for the basal positioning of the SpaE pilin within the SpaFED pilus.
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Affiliation(s)
- Abhin Kumar Megta
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana 121 001, India; School of Biotechnology, KIIT University, Odisha 751024, India
| | - Arjun K Mishra
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana 121 001, India
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | | | - Vengadesan Krishnan
- Laboratory of Structural Biology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, Haryana 121 001, India.
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16
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Yan Z, Cui Y, Zhou W, Li W, Tan X, Chen W, Zhang J, Jiang Y. Molecular characterization of Streptococcus pneumoniae in children living in southwest China and assessment of a potential protein vaccine, rPfbA. Vaccine 2019; 37:721-731. [DOI: 10.1016/j.vaccine.2018.12.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/28/2018] [Accepted: 12/11/2018] [Indexed: 10/27/2022]
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17
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Qian Y, Zhang Y, Yu Y, Li Q, Guo G, Fu Y, Yao H, Lu C, Zhang W. SBP1 is an adhesion-associated factor without the involvement of virulence in Streptococcus suis serotype 2. Microb Pathog 2018; 122:90-97. [DOI: 10.1016/j.micpath.2018.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 05/22/2018] [Accepted: 06/06/2018] [Indexed: 11/29/2022]
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18
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Becke TD, Ness S, Sudhop S, Gaub HE, Hilleringmann M, Schilling AF, Clausen-Schaumann H. Covalent Immobilization of Proteins for the Single Molecule Force Spectroscopy. J Vis Exp 2018. [PMID: 30176022 PMCID: PMC6128213 DOI: 10.3791/58167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In recent years, atomic force microscopy (AFM) based single molecule force spectroscopy (SMFS) extended our understanding of molecular properties and functions. It gave us the opportunity to explore a multiplicity of biophysical mechanisms, e.g., how bacterial adhesins bind to host surface receptors in more detail. Among other factors, the success of SMFS experiments depends on the functional and native immobilization of the biomolecules of interest on solid surfaces and AFM tips. Here, we describe a straightforward protocol for the covalent coupling of proteins to silicon surfaces using silane-PEG-carboxyls and the well-established N-hydroxysuccinimid/1-ethyl-3-(3-dimethyl-aminopropyl)carbodiimid (EDC/NHS) chemistry in order to explore the interaction of pilus-1 adhesin RrgA from the Gram-positive bacterium Streptococcus pneumoniae (S. pneumoniae) with the extracellular matrix protein fibronectin (Fn). Our results show that the surface functionalization leads to a homogenous distribution of Fn on the glass surface and to an appropriate concentration of RrgA on the AFM cantilever tip, apparent by the target value of up to 20% of interaction events during SMFS measurements and revealed that RrgA binds to Fn with a mean force of 52 pN. The protocol can be adjusted to couple via site specific free thiol groups. This results in a predefined protein or molecule orientation and is suitable for other biophysical applications besides the SMFS.
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Affiliation(s)
- Tanja D Becke
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München;
| | - Stefan Ness
- FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences
| | - Stefanie Sudhop
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München
| | - Hermann E Gaub
- Center for Nano Science, Ludwig-Maximilians-Universität München
| | - Markus Hilleringmann
- FG Protein Biochemistry & Cellular Microbiology, Munich University of Applied Sciences
| | - Arndt F Schilling
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, University Medical Center Göttingen
| | - Hauke Clausen-Schaumann
- Center for Applied Tissue Engineering and Regenerative Medicine, Munich University of Applied Sciences; Center for Nano Science, Ludwig-Maximilians-Universität München
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19
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Streptococcus pneumoniae two-component regulatory systems: The interplay of the pneumococcus with its environment. Int J Med Microbiol 2018; 308:722-737. [DOI: 10.1016/j.ijmm.2017.11.012] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 11/21/2017] [Accepted: 11/24/2017] [Indexed: 02/06/2023] Open
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20
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Formosa-Dague C, Castelain M, Martin-Yken H, Dunker K, Dague E, Sletmoen M. The Role of Glycans in Bacterial Adhesion to Mucosal Surfaces: How Can Single-Molecule Techniques Advance Our Understanding? Microorganisms 2018; 6:E39. [PMID: 29734645 PMCID: PMC6027152 DOI: 10.3390/microorganisms6020039] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 04/24/2018] [Accepted: 04/26/2018] [Indexed: 12/14/2022] Open
Abstract
Bacterial adhesion is currently the subject of increased interest from the research community, leading to fast progress in our understanding of this complex phenomenon. Resent research within this field has documented the important roles played by glycans for bacterial surface adhesion, either through interaction with lectins or with other glycans. In parallel with this increased interest for and understanding of bacterial adhesion, there has been a growth in the sophistication and use of sensitive force probes for single-molecule and single cell studies. In this review, we highlight how the sensitive force probes atomic force microscopy (AFM) and optical tweezers (OT) have contributed to clarifying the mechanisms underlying bacterial adhesion to glycosylated surfaces in general and mucosal surfaces in particular. We also describe research areas where these techniques have not yet been applied, but where their capabilities appear appropriate to advance our understanding.
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Affiliation(s)
| | - Mickaël Castelain
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31400 Toulouse, France.
| | - Hélène Martin-Yken
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31400 Toulouse, France.
| | - Karen Dunker
- Department of Biotechnology and Food Science, NTNU the Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
| | - Etienne Dague
- LAAS-CNRS, Université de Toulouse, CNRS, 31400 Toulouse, France.
| | - Marit Sletmoen
- Department of Biotechnology and Food Science, NTNU the Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
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21
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Contribution of Pili of S. Pneumoniae in the Onset of Meningitis. FOLIA VETERINARIA 2018. [DOI: 10.2478/fv-2018-0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Bacterial meningitis is a devastating worldwide disease. Half of the survivors of meningitis remain with permanent neurological sequelae. The pathogenesis of meningitis is based on a complex host-pathogen interaction. Streptococcus pneumoniae is a life-threatening neuroinvasive pathogen that asymptomatically colonizes the upper respiratory tract. Adherence of pneumococci to the host epithelium is a prerequisite in the onset of streptococcal infections; such adherence is favored by the formation of bacterial pili. In this article, we will describe the pneumococcal pili and its contribution to the onset of meningitis.
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22
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Engholm DH, Kilian M, Goodsell DS, Andersen ES, Kjærgaard RS. A visual review of the human pathogen Streptococcus pneumoniae. FEMS Microbiol Rev 2018; 41:854-879. [PMID: 29029129 DOI: 10.1093/femsre/fux037] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 09/04/2017] [Indexed: 11/12/2022] Open
Abstract
Being the principal causative agent of bacterial pneumonia, otitis media, meningitis and septicemia, the bacterium Streptococcus pneumoniae is a major global health problem. To highlight the molecular basis of this problem, we have portrayed essential biological processes of the pneumococcal life cycle in eight watercolor paintings. The paintings are done to a consistent nanometer scale based on currently available data from structural biology and proteomics. In this review article, the paintings are used to provide a visual review of protein synthesis, carbohydrate metabolism, cell wall synthesis, cell division, teichoic acid synthesis, virulence, transformation and pilus synthesis based on the available scientific literature within the field of pneumococcal biology. Visualization of the molecular details of these processes reveals several scientific questions about how molecular components of the pneumococcal cell are organized to allow biological function to take place. By the presentation of this visual review, we intend to stimulate scientific discussion, aid in the generation of scientific hypotheses and increase public awareness. A narrated video describing the biological processes in the context of a whole-cell illustration accompany this article.
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Affiliation(s)
- Ditte Høyer Engholm
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark
| | - Mogens Kilian
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - David S Goodsell
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA.,Rutgers, the State University of New Jersey, NJ 08901, USA
| | - Ebbe Sloth Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark.,Interdisciplinary Nanoscience Center, Aarhus University, 8000 Aarhus, Denmark
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23
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Becke TD, Ness S, Gürster R, Schilling AF, di Guilmi AM, Sudhop S, Hilleringmann M, Clausen-Schaumann H. Single Molecule Force Spectroscopy Reveals Two-Domain Binding Mode of Pilus-1 Tip Protein RrgA of Streptococcus pneumoniae to Fibronectin. ACS NANO 2018; 12:549-558. [PMID: 29298375 DOI: 10.1021/acsnano.7b07247] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
For host cell adhesion and invasion, surface piliation procures benefits for bacteria. A detailed investigation of how pili adhere to host cells is therefore a key aspect in understanding their role during infection. Streptococcus pneumoniae TIGR 4, a clinical relevant serotype 4 strain, is capable of expressing pilus-1 with terminal RrgA, an adhesin interacting with host extracellular matrix (ECM) proteins. We used single molecule force spectroscopy to investigate the binding of full-length RrgA and single RrgA domains to fibronectin. Our results show that full-length RrgA and its terminal domains D3 and D4 bind to fibronectin with forces of 51.6 (full length), 52.8 (D3), and 46.2 pN (D4) at force-loading rates of around 1500 pN/s. Selective saturation of D3 and D4 binding sites on fibronectin showed that both domains can interact simultaneously with fibronectin, revealing a two-domain binding mechanism for the pilus-1 tip protein. The high off rates and the corresponding short lifetime of the RrgA Fn bond (τ = 0.26 s) may enable piliated pneumococci to form and maintain a transient contact to fibronectin-containing host surfaces and thus to efficiently scan the surface for specific receptors promoting host cell adhesion and invasion. These molecular properties could be essential for S. pneumoniae pili to mediate initial contact to the host cells and-shared with other piliated Gram-positive bacteria-favor host invasion.
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Affiliation(s)
- Tanja D Becke
- Department for Plastic Surgery and Hand Surgery, Klinikum Rechts der Isar, Technische Universität München , 81675 Munich, Germany
- Center for NanoScience, Ludwig-Maximilians-Universität München , 80799 Munich, Germany
| | | | | | - Arndt F Schilling
- Department for Plastic Surgery and Hand Surgery, Klinikum Rechts der Isar, Technische Universität München , 81675 Munich, Germany
- Klinik für Unfallchirurgie, Orthopädie und Plastische Chirurgie, University Medical Center Göttingen , 37075 Göttingen, Germany
| | | | - Stefanie Sudhop
- Center for NanoScience, Ludwig-Maximilians-Universität München , 80799 Munich, Germany
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24
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Abstract
Streptococcus pneumoniae is a leading cause of morbidity and mortality globally. The Pilus-1 proteins, RrgA, RrgB and RrgC of S. pneumoniae have been previously assessed for their role in infection, invasive disease and as possible vaccine candidates. In this study we have investigated the glycan binding repertoire of all three Pilus-1 proteins, identifying that the tip adhesin RrgA has the broadest glycan recognition of the three proteins, binding to maltose/cellobiose, α/β linked galactose and blood group A and H antigens. RrgB only bound mannose, while RrgC bound a subset of glycans also recognized by RrgA. Adherence of S. pneumoniae TIGR4 to epithelial cells was tested using four of the oligosaccharides identified through the glycan array analysis as competitive inhibitors. The blood group H trisaccharide provided the best blocking of S. pneumoniae TIGR4 adherence. Adherence is the first step in disease, and host glycoconjugates are a common target for many adhesins. This study has identified Pilus-1 proteins as new lectins involved in the targeting of host glycosylation by S. pneumoniae.
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25
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von Ossowski I. Novel Molecular Insights about Lactobacillar Sortase-Dependent Piliation. Int J Mol Sci 2017; 18:ijms18071551. [PMID: 28718795 PMCID: PMC5536039 DOI: 10.3390/ijms18071551] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/11/2017] [Accepted: 07/14/2017] [Indexed: 01/09/2023] Open
Abstract
One of the more conspicuous structural features that punctuate the outer cell surface of certain bacterial Gram-positive genera and species is the sortase-dependent pilus. As these adhesive and variable-length protrusions jut outward from the cell, they provide a physically expedient and useful means for the initial contact between a bacterium and its ecological milieu. The sortase-dependent pilus displays an elongated macromolecular architecture consisting of two to three types of monomeric protein subunits (pilins), each with their own specific function and location, and that are joined together covalently by the transpeptidyl activity of a pilus-specific C-type sortase enzyme. Sortase-dependent pili were first detected among the Gram-positive pathogens and subsequently categorized as an essential virulence factor for host colonization and tissue invasion by these harmful bacteria. However, the sortase-dependent pilus was rebranded as also a niche-adaptation factor after it was revealed that “friendly” Gram-positive commensals exhibit the same kind of pilus structures, which includes two contrasting gut-adapted species from the Lactobacillus genus, allochthonous Lactobacillus rhamnosus and autochthonous Lactobacillus ruminis. This review will highlight and discuss what has been learned from the latest research carried out and published on these lactobacillar pilus types.
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Affiliation(s)
- Ingemar von Ossowski
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki FIN-00014, Finland.
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26
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Khare B, V L Narayana S. Pilus biogenesis of Gram-positive bacteria: Roles of sortases and implications for assembly. Protein Sci 2017; 26:1458-1473. [PMID: 28493331 DOI: 10.1002/pro.3191] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 04/28/2017] [Accepted: 05/03/2017] [Indexed: 12/26/2022]
Abstract
Successful adherence, colonization, and survival of Gram-positive bacteria require surface proteins, and multiprotein assemblies called pili. These surface appendages are attractive pharmacotherapeutic targets and understanding their assembly mechanisms is essential for identifying a new class of 'anti-infectives' that do not elicit microbial resistance. Molecular details of the Gram-negative pilus assembly are available indepth, but the Gram-positive pilus biogenesis is still an emerging field and investigations continue to reveal novel insights into this process. Pilus biogenesis in Gram-positive bacteria is a biphasic process that requires enzymes called pilus-sortases for assembly and a housekeeping sortase for covalent attachment of the assembled pilus to the peptidoglycan cell wall. Emerging structural and functional data indicate that there are at least two groups of Gram-positive pili, which require either the Class C sortase or Class B sortase in conjunction with LepA/SipA protein for major pilin polymerization. This observation suggests two distinct modes of sortase-mediated pilus biogenesis in Gram-positive bacteria. Here we review the structural and functional biology of the pilus-sortases from select streptococcal pilus systems and their role in Gram-positive pilus assembly.
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Affiliation(s)
- Baldeep Khare
- Center for Structural Biology, School of Optometry, University of Alabama at Birmingham, Birmingham, USA
| | - Sthanam V L Narayana
- Center for Structural Biology, School of Optometry, University of Alabama at Birmingham, Birmingham, USA
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27
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Andre GO, Converso TR, Politano WR, Ferraz LFC, Ribeiro ML, Leite LCC, Darrieux M. Role of Streptococcus pneumoniae Proteins in Evasion of Complement-Mediated Immunity. Front Microbiol 2017; 8:224. [PMID: 28265264 PMCID: PMC5316553 DOI: 10.3389/fmicb.2017.00224] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/31/2017] [Indexed: 12/14/2022] Open
Abstract
The complement system plays a central role in immune defense against Streptococcus pneumoniae. In order to evade complement attack, pneumococci have evolved a number of mechanisms that limit complement mediated opsonization and subsequent phagocytosis. This review focuses on the strategies employed by pneumococci to circumvent complement mediated immunity, both in vitro and in vivo. At last, since many of the proteins involved in interactions with complement components are vaccine candidates in different stages of validation, we explore the use of these antigens alone or in combination, as potential vaccine approaches that aim at elimination or drastic reduction in the ability of this bacterium to evade complement.
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Affiliation(s)
- Greiciely O Andre
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Thiago R Converso
- Centro de Biotecnologia, Instituto ButantanSão Paulo, Brazil; Programa de Pós-graduação Interunidades em Biotecnologia, Universidade de São PauloSão Paulo, Brazil
| | - Walter R Politano
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Lucio F C Ferraz
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
| | - Marcelo L Ribeiro
- Laboratório de Farmacologia, Universidade São Francisco Bragança Paulista, Brazil
| | | | - Michelle Darrieux
- Laboratório de Biologia Celular e Molecular de Microrganismos, Universidade São Francisco Bragança Paulista, Brazil
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28
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Chaguza C, Cornick JE, Harris SR, Andam CP, Bricio-Moreno L, Yang M, Yalcin F, Ousmane S, Govindpersad S, Senghore M, Ebruke C, Du Plessis M, Kiran AM, Pluschke G, Sigauque B, McGee L, Klugman KP, Turner P, Corander J, Parkhill J, Collard JM, Antonio M, von Gottberg A, Heyderman RS, French N, Kadioglu A, Hanage WP, Everett DB, Bentley SD. Understanding pneumococcal serotype 1 biology through population genomic analysis. BMC Infect Dis 2016; 16:649. [PMID: 27821148 PMCID: PMC5100261 DOI: 10.1186/s12879-016-1987-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 10/30/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pneumococcus kills over one million children annually and over 90 % of these deaths occur in low-income countries especially in Sub-Saharan Africa (SSA) where HIV exacerbates the disease burden. In SSA, serotype 1 pneumococci particularly the endemic ST217 clone, causes majority of the pneumococcal disease burden. To understand the evolution of the virulent ST217 clone, we analysed ST217 whole genomes from isolates sampled from African and Asian countries. METHODS We analysed 226 whole genome sequences from the ST217 lineage sampled from 9 African and 4 Asian countries. We constructed a whole genome alignment and used it for phylogenetic and coalescent analyses. We also screened the genomes to determine presence of antibiotic resistance conferring genes. RESULTS Population structure analysis grouped the ST217 isolates into five sequence clusters (SCs), which were highly associated with different geographical regions and showed limited intracontinental and intercontinental spread. The SCs showed lower than expected genomic sequence, which suggested strong purifying selection and small population sizes caused by bottlenecks. Recombination rates varied between the SCs but were lower than in other successful clones such as PMEN1. African isolates showed higher prevalence of antibiotic resistance genes than Asian isolates. Interestingly, certain West African isolates harbored a defective chloramphenicol and tetracycline resistance-conferring element (Tn5253) with a deletion in the loci encoding the chloramphenicol resistance gene (cat pC194), which caused lower chloramphenicol than tetracycline resistance. Furthermore, certain genes that promote colonisation were absent in the isolates, which may contribute to serotype 1's rarity in carriage and consequently its lower recombination rates. CONCLUSIONS The high phylogeographic diversity of the ST217 clone shows that this clone has been in circulation globally for a long time, which allowed its diversification and adaptation in different geographical regions. Such geographic adaptation reflects local variations in selection pressures in different locales. Further studies will be required to fully understand the biological mechanisms which makes the ST217 clone highly invasive but unable to successfully colonise the human nasopharynx for long durations which results in lower recombination rates.
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Affiliation(s)
- Chrispin Chaguza
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Jennifer E. Cornick
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Simon R. Harris
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, CB10 1SA UK
| | - Cheryl P. Andam
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Department of Epidemiology, Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, Massachusetts, MA 02115 USA
| | - Laura Bricio-Moreno
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
| | - Marie Yang
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
| | - Feyruz Yalcin
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, CB10 1SA UK
| | - Sani Ousmane
- Unité de Biologie, Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Shanil Govindpersad
- National Institute for Communicable Diseases (NICD), Johannesburg, South Africa
| | - Madikay Senghore
- Bacterial Diseases Programme, Medical Research Council (MRC), Banjul, The Gambia
- Division of Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK
| | - Chinelo Ebruke
- Bacterial Diseases Programme, Medical Research Council (MRC), Banjul, The Gambia
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | - Mignon Du Plessis
- National Institute for Communicable Diseases (NICD), Johannesburg, South Africa
| | - Anmol M. Kiran
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Gerd Pluschke
- Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Betuel Sigauque
- Centro de Investigação em Saúde da Manhiça, Maputo, Mozambique
| | - Lesley McGee
- Respiratory Diseases Branch, Centers for Disease Control and Prevention, Atlanta, Georgia GA 30329 USA
| | - Keith P. Klugman
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322 USA
- Bill and Melinda Gates Foundation, Seattle, WA 98109 USA
| | - Paul Turner
- Cambodia Oxford Medical Research Unit, Angkor Hospital for Children, Siem Reap, Cambodia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7FZ UK
| | - Jukka Corander
- Department of Mathematics and Statistics, University of Helsinki, Helsinki, Finland
| | - Julian Parkhill
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, CB10 1SA UK
| | - Jean-Marc Collard
- Unité de Biologie, Centre de Recherche Médicale et Sanitaire (CERMES), Niamey, Niger
| | - Martin Antonio
- Bacterial Diseases Programme, Medical Research Council (MRC), Banjul, The Gambia
- Division of Translational and Systems Medicine, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, WC1E 7HT UK
| | - Anne von Gottberg
- National Institute for Communicable Diseases (NICD), Johannesburg, South Africa
- School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Robert S. Heyderman
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, Blantyre, Malawi
- Division of Infection and Immunity, University College London, London, WC1E 6BT UK
| | - Neil French
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Aras Kadioglu
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
| | - William P. Hanage
- Department of Epidemiology, Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, Massachusetts, MA 02115 USA
| | - Dean B. Everett
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Queen Elizabeth Central Hospital, Blantyre, Malawi
| | - Stephen D. Bentley
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE UK
- Pathogen Genomics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Cambridge, CB10 1SA UK
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A distinct sortase SrtB anchors and processes a streptococcal adhesin AbpA with a novel structural property. Sci Rep 2016; 6:30966. [PMID: 27492581 PMCID: PMC4974636 DOI: 10.1038/srep30966] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 07/06/2016] [Indexed: 02/06/2023] Open
Abstract
Surface display of proteins by sortases in Gram-positive bacteria is crucial for bacterial fitness and virulence. We found a unique gene locus encoding an amylase-binding adhesin AbpA and a sortase B in oral streptococci. AbpA possesses a new distinct C-terminal cell wall sorting signal. We demonstrated that this C-terminal motif is required for anchoring AbpA to cell wall. In vitro and in vivo studies revealed that SrtB has dual functions, anchoring AbpA to the cell wall and processing AbpA into a ladder profile. Solution structure of AbpA determined by NMR reveals a novel structure comprising a small globular α/β domain and an extended coiled-coil heliacal domain. Structural and biochemical studies identified key residues that are crucial for amylase binding. Taken together, our studies document a unique sortase/adhesion substrate system in streptococci adapted to the oral environment rich in salivary amylase.
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30
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Chaurasia P, Pratap S, von Ossowski I, Palva A, Krishnan V. New insights about pilus formation in gut-adapted Lactobacillus rhamnosus GG from the crystal structure of the SpaA backbone-pilin subunit. Sci Rep 2016; 6:28664. [PMID: 27349405 PMCID: PMC4923907 DOI: 10.1038/srep28664] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/08/2016] [Indexed: 12/11/2022] Open
Abstract
Thus far, all solved structures of pilin-proteins comprising sortase-assembled pili are from pathogenic genera and species. Here, we present the first crystal structure of a pilin subunit (SpaA) from a non-pathogen host (Lactobacillus rhamnosus GG). SpaA consists of two tandem CnaB-type domains, each with an isopeptide bond and E-box motif. Intriguingly, while the isopeptide bond in the N-terminal domain forms between lysine and asparagine, the one in the C-terminal domain atypically involves aspartate. We also solved crystal structures of mutant proteins where residues implicated in forming isopeptide bonds were replaced. Expectedly, the E-box-substituted E139A mutant lacks an isopeptide bond in the N-terminal domain. However, the C-terminal E269A substitution gave two structures; one of both domains with their isopeptide bonds present, and another of only the N-terminal domain, but with an unformed isopeptide bond and significant conformational changes. This latter crystal structure has never been observed for any other Gram-positive pilin. Notably, the C-terminal isopeptide bond still forms in D295N-substituted SpaA, irrespective of E269 being present or absent. Although E-box mutations affect SpaA proteolytic and thermal stability, a cumulative effect perturbing normal pilus polymerization was unobserved. A model showing the polymerized arrangement of SpaA within the SpaCBA pilus is proposed.
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Affiliation(s)
- Priyanka Chaurasia
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-121 001, India.,Department of Biotechnology, Manipal University, Karnataka, 576104, India
| | - Shivendra Pratap
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-121 001, India
| | | | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Vengadesan Krishnan
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad-121 001, India
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31
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Vaccine escape of piliated Streptococcus pneumoniae strains. Vaccine 2016; 34:2787-92. [DOI: 10.1016/j.vaccine.2016.04.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/16/2016] [Accepted: 04/20/2016] [Indexed: 11/20/2022]
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32
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Castelain M, Duviau MP, Canette A, Schmitz P, Loubière P, Cocaign-Bousquet M, Piard JC, Mercier-Bonin M. The Nanomechanical Properties of Lactococcus lactis Pili Are Conditioned by the Polymerized Backbone Pilin. PLoS One 2016; 11:e0152053. [PMID: 27010408 PMCID: PMC4806873 DOI: 10.1371/journal.pone.0152053] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 03/08/2016] [Indexed: 12/16/2022] Open
Abstract
Pili produced by Lactococcus lactis subsp. lactis are putative linear structures consisting of repetitive subunits of the major pilin PilB that forms the backbone, pilin PilA situated at the distal end of the pilus, and an anchoring pilin PilC that tethers the pilus to the peptidoglycan. We determined the nanomechanical properties of pili using optical-tweezers force spectroscopy. Single pili were exposed to optical forces that yielded force-versus-extension spectra fitted using the Worm-Like Chain model. Native pili subjected to a force of 0–200 pN exhibit an inextensible, but highly flexible ultrastructure, reflected by their short persistence length. We tested a panel of derived strains to understand the functional role of the different pilins. First, we found that both the major pilin PilB and sortase C organize the backbone into a full-length organelle and dictate the nanomechanical properties of the pili. Second, we found that both PilA tip pilin and PilC anchoring pilin were not essential for the nanomechanical properties of pili. However, PilC maintains the pilus on the bacterial surface and may play a crucial role in the adhesion- and biofilm-forming properties of L. lactis.
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Affiliation(s)
- Mickaël Castelain
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400, Toulouse, France
- CNRS, UMR5504, F-31400, Toulouse, France
- * E-mail:
| | - Marie-Pierre Duviau
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400, Toulouse, France
- CNRS, UMR5504, F-31400, Toulouse, France
| | - Alexis Canette
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Philippe Schmitz
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400, Toulouse, France
- CNRS, UMR5504, F-31400, Toulouse, France
| | - Pascal Loubière
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400, Toulouse, France
- CNRS, UMR5504, F-31400, Toulouse, France
| | - Muriel Cocaign-Bousquet
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400, Toulouse, France
- CNRS, UMR5504, F-31400, Toulouse, France
| | - Jean-Christophe Piard
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Muriel Mercier-Bonin
- Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077, Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400, Toulouse, France
- CNRS, UMR5504, F-31400, Toulouse, France
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CnaA domains in bacterial pili are efficient dissipaters of large mechanical shocks. Proc Natl Acad Sci U S A 2016; 113:2490-5. [PMID: 26884173 DOI: 10.1073/pnas.1522946113] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Pathogenic bacteria adhere despite severe mechanical perturbations induced by the host, such as coughing. In Gram-positive bacteria, extracellular protein appendages termed pili are necessary for adherence under mechanical stress. However, little is known about the behavior of Gram-positive pili under force. Here, we demonstrate a mechanism by which Gram-positive pili are able to dissipate mechanical energy through mechanical unfolding and refolding of isopeptide bond-delimited polypeptide loops present in Ig-type CnaA domains. Using single-molecule force spectroscopy, we find that these loops of the pilus subunit SpaA of the SpaA-type pilus from Corynebacterium diphtheriae and FimA of the type 2 pilus from Actinomyces oris unfold and extend at forces that are the highest yet reported for globular proteins. Loop refolding is limited by the hydrophobic collapse of the polypeptide and occurs in milliseconds. Remarkably, both SpaA and FimA initially refold to mechanically weaker intermediates that recover strength with time or ligand binding. Based on the high force extensibility, CnaA-containing pili can dissipate ∼28-fold as much energy compared with their inextensible counterparts before reaching forces sufficient to cleave covalent bonds. We propose that efficient mechanical energy dissipation is key for sustained bacterial attachment against mechanical perturbations.
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34
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Amerighi F, Valeri M, Donnarumma D, Maccari S, Moschioni M, Taddei A, Lapazio L, Pansegrau W, Buccato S, De Angelis G, Ruggiero P, Masignani V, Soriani M, Pezzicoli A. Identification of a Monoclonal Antibody Against Pneumococcal Pilus 1 Ancillary Protein Impairing Bacterial Adhesion to Human Epithelial Cells. J Infect Dis 2015; 213:516-22. [PMID: 26401026 DOI: 10.1093/infdis/jiv461] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/11/2015] [Indexed: 12/17/2022] Open
Abstract
The adhesion of Streptococcus pneumoniae is a key step during colonization of human respiratory tract mucosae. Here we demonstrate that pneumococcal type I pilus significantly increases the adhesiveness of poorly adhering highly capsulated strains in vitro. Interestingly, preincubation of bacteria with antibodies against the major pilus backbone subunit (RrgB) or the adhesin component (RrgA) impaired pneumococcal association to human epithelial cells. Screening for anti-RrgA monoclonal antibodies specifically affecting the adhesive capacity of S. pneumoniae led to the identification of the monoclonal 11B9/61 antibody, which greatly reduced pilus-dependent cell contact. Proteomic-based epitope mapping of 11B9/61 monoclonal antibody revealed a well-exposed epitope on the D2 domain of RrgA as the target of this functional antibody. The data presented here confirm the importance of pilus I for S. pneumoniae pathogenesis and the potential use of antipilus antibodies to prevent bacterial colonization.
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Affiliation(s)
| | - Maria Valeri
- Institute for Immunology, University of California-Irvine School of Medicine
| | | | | | | | - Annarita Taddei
- Interdepartmental Centre for Electron Microscopy, University of Tuscia, Viterbo, Italy
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Shaik MM, Lombardi C, Maragno Trindade D, Fenel D, Schoehn G, Di Guilmi AM, Dessen A. A structural snapshot of type II pilus formation in Streptococcus pneumoniae. J Biol Chem 2015. [PMID: 26198632 DOI: 10.1074/jbc.m115.647834] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pili are fibrous appendages expressed on the surface of a vast number of bacterial species, and their role in surface adhesion is important for processes such as infection, colonization, andbiofilm formation. The human pathogen Streptococcus pneumoniae expresses two different types of pili, PI-1 and PI-2, both of which require the concerted action of structural proteins and sortases for their polymerization. The type PI-1 streptococcal pilus is a complex, well studied structure, but the PI-2 type, present in a number of invasive pneumococcal serotypes, has to date remained less well understood. The PI-2 pilus consists of repeated units of a single protein, PitB, whose covalent association is catalyzed by cognate sortase SrtG-1 and partner protein SipA. Here we report the high resolution crystal structures of PitB and SrtG1 and use molecular modeling to visualize a "trapped" 1:1 complex between the two molecules. X-ray crystallography and electron microscopy reveal that the pneumococcal PI-2 backbone fiber is formed by PitB monomers associated in head-to-tail fashion and that short, flexible fibers can be formed even in the absence of coadjuvant proteins. These observations, obtained with a simple pilus biosynthetic system, are likely to be applicable to other fiber formation processes in a variety of Gram-positive organisms.
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Affiliation(s)
- Md Munan Shaik
- From the Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France, CNRS, IBS, 38044 Grenoble, France, Commissariat à l'Energie Atomique, IBS, Grenoble, France, and
| | - Charlotte Lombardi
- From the Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France, CNRS, IBS, 38044 Grenoble, France, Commissariat à l'Energie Atomique, IBS, Grenoble, France, and
| | - Daniel Maragno Trindade
- Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, 13083 São Paulo, Brazil
| | - Daphna Fenel
- From the Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France, CNRS, IBS, 38044 Grenoble, France, Commissariat à l'Energie Atomique, IBS, Grenoble, France, and
| | - Guy Schoehn
- From the Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France, CNRS, IBS, 38044 Grenoble, France, Commissariat à l'Energie Atomique, IBS, Grenoble, France, and
| | - Anne Marie Di Guilmi
- From the Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France, CNRS, IBS, 38044 Grenoble, France, Commissariat à l'Energie Atomique, IBS, Grenoble, France, and
| | - Andréa Dessen
- From the Université Grenoble Alpes, Institut de Biologie Structurale (IBS), F-38044 Grenoble, France, CNRS, IBS, 38044 Grenoble, France, Commissariat à l'Energie Atomique, IBS, Grenoble, France, and Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, 13083 São Paulo, Brazil
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36
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Krishnan V. Pilins in gram-positive bacteria: A structural perspective. IUBMB Life 2015; 67:533-43. [PMID: 26178080 DOI: 10.1002/iub.1400] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/17/2015] [Indexed: 11/11/2022]
Abstract
Pilins or fimbrilins are a class of proteins found in bacterial surface pilus, a hair-like surface appendage. Both the Gram-negative and -positive bacteria produce pilins to assemble pili on their cell-surface for different purposes including adherence, twitching motility, conjugation, immunomodulation, biofilm formation, and electron transfer. Immunogenic properties of the pilins make them attractive vaccine candidates. The polymerized pilins play a key role in the initiation of host adhesion, which is a critical step for bacterial colonization and infection. Because of their key role in adhesion and exposure on the cell surface, targeting the pilins-mediated adhesion (anti-adhesion therapy) is also seen as a promising alternative approach for preventing and treating bacterial infections, one that may overcome their ever-increasing repertoires of resistance mechanisms. Individual pilins interact with each other non-covalently to assemble the pilus fiber with the help of associated proteins like chaperones and Usher in Gram-negative bacteria. In contrast, the pilins in Gram-positive bacteria often connect with each other covalently, with the help of sortases. Certain unique structural features present on the pilins distinguish them from one another across different bacterial strains, and these dictate their cellular targets and functions. While the structure of pilins has been extensively studied in Gram-negative pathogenic bacteria, the pilins in Gram-positive pathogenic bacteria have been in only during the last decade. Recently, the discovery of pilins in non-pathogenic bacteria, such as Lactobacillus rhamnosus GG, has received great attention, though traditionally the attention was on pathogenic bacteria. This review summarizes and discusses the current structural knowledge of pilins in Gram-positive bacteria with emphasis on those pilins which are sortase substrates.
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Affiliation(s)
- Vengadesan Krishnan
- Regional Centre for Biotechnology, NCR-Biotech Science Cluster, Faridabad-121 001, Haryana, India
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37
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Gruszka DT, Whelan F, Farrance OE, Fung HKH, Paci E, Jeffries CM, Svergun DI, Baldock C, Baumann CG, Brockwell DJ, Potts JR, Clarke J. Cooperative folding of intrinsically disordered domains drives assembly of a strong elongated protein. Nat Commun 2015; 6:7271. [PMID: 26027519 PMCID: PMC4458895 DOI: 10.1038/ncomms8271] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/23/2015] [Indexed: 11/09/2022] Open
Abstract
Bacteria exploit surface proteins to adhere to other bacteria, surfaces and host cells. Such proteins need to project away from the bacterial surface and resist significant mechanical forces. SasG is a protein that forms extended fibrils on the surface of Staphylococcus aureus and promotes host adherence and biofilm formation. Here we show that although monomeric and lacking covalent cross-links, SasG maintains a highly extended conformation in solution. This extension is mediated through obligate folding cooperativity of the intrinsically disordered E domains that couple non-adjacent G5 domains thermodynamically, forming interfaces that are more stable than the domains themselves. Thus, counterintuitively, the elongation of the protein appears to be dependent on the inherent instability of its domains. The remarkable mechanical strength of SasG arises from tandemly arrayed 'clamp' motifs within the folded domains. Our findings reveal an elegant minimal solution for the assembly of monomeric mechano-resistant tethers of variable length.
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Affiliation(s)
- Dominika T. Gruszka
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Fiona Whelan
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Oliver E. Farrance
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Herman K. H. Fung
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Emanuele Paci
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Cy M. Jeffries
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22603 Hamburg, Germany
| | - Dmitri I. Svergun
- European Molecular Biology Laboratory, Hamburg Unit, Notkestrasse 85, 22603 Hamburg, Germany
| | - Clair Baldock
- Faculty of Life Sciences, Wellcome Trust Centre for Cell-Matrix Research, University of Manchester, Michael Smith Building, Greater Manchester M13 9PT, UK
| | | | - David J. Brockwell
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK
| | - Jennifer R. Potts
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Jane Clarke
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
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Abstract
Pili of Gram-positive bacteria are unique structures on the bacterial surface, assembled from covalently linked polypeptide subunits. Pilus assembly proceeds by transpeptidation reactions catalyzed by sortases, followed by covalent anchoring of the filament in the peptidoglycan layer. Another distinctive property is the presence of intramolecular isopeptide bonds, conferring extraordinary chemical and mechanical stability to these elongated structures. Besides their function in cell adhesion and biofilm formation, this section discusses possible application of pilus constituents as vaccine components against Gram-positive pathogens.
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Electron microscopy of Staphylococcus epidermidis fibril and biofilm formation using image-enhancing ionic liquid. Anal Bioanal Chem 2014; 407:1607-13. [DOI: 10.1007/s00216-014-8391-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/21/2014] [Accepted: 12/03/2014] [Indexed: 01/09/2023]
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Shakrin NNSM, Masri SN, Taib NM, Nordin SA, Jamal F, Desa MNM. Genotypic characterization of Malaysian human isolates of Streptococcus pneumoniae from carriage and clinical sources. Comp Immunol Microbiol Infect Dis 2014; 37:347-54. [DOI: 10.1016/j.cimid.2014.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 10/08/2014] [Accepted: 10/20/2014] [Indexed: 10/24/2022]
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41
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Unencapsulated Streptococcus pneumoniae from conjunctivitis encode variant traits and belong to a distinct phylogenetic cluster. Nat Commun 2014; 5:5411. [PMID: 25388376 PMCID: PMC4231546 DOI: 10.1038/ncomms6411] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 09/29/2014] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae, an inhabitant of the upper respiratory mucosa, causes respiratory and invasive infections as well as conjunctivitis. Strains that lack the capsule, a main virulence factor and the target of current vaccines, are often isolated from conjunctivitis cases. Here we perform a comparative genomic analysis of 271 strains of conjunctivitis-causing S. pneumoniae from 72 postal codes in the US. We find that the vast majority of conjunctivitis strains are members of a distinct cluster of closely related unencapsulated strains. These strains possess divergent forms of pneumococcal virulence factors (such as CbpA and neuraminidases) that are not shared with other unencapsulated nasopharyngeal S. pneumoniae. They also possess putative adhesins that have not been described in encapsulated pneumococci. These findings suggest that the unencapsulated strains capable of causing conjunctivitis utilize a pathogenesis strategy substantially different from that described for S. pneumoniae at other infection sites.
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Tiouajni M, Durand D, Blondeau K, Graille M, Urvoas A, Valerio-Lepiniec M, Guellouz A, Aumont-Nicaise M, Minard P, van Tilbeurgh H. Structural and functional analysis of the fibronectin-binding protein FNE from Streptococcus equi spp. equi. FEBS J 2014; 281:5513-31. [PMID: 25290767 DOI: 10.1111/febs.13092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/24/2014] [Accepted: 09/30/2014] [Indexed: 12/17/2022]
Abstract
Streptococcus equi is a horse pathogen belonging to Lancefield group C. Infection by S. equi ssp. equi causes strangles, a serious and highly contagious disease of the upper respiratory tract. S. equi ssp. equi secretes a fibronectin (Fn)-binding protein, FNE, that does not contain cell wall-anchoring motifs. FNE binds to the gelatin-binding domain (GBD) of Fn, composed of the motifs (6) FI (12) FII (789) FI . FNE lacks the canonical Fn-binding peptide repeats observed in many microbial surface components recognizing adhesive matrix molecules. We found that the interaction between FNE and the human GBD is mediated by the binding of the disordered C-terminal region (residues 208-262) of FNE to the (789) FI GBD subfragment. The crystal structure of FNE showed that it is similar to the minor pilus protein Spy0125 of Streptococcus pyogenes, found at the end of pilus polymers and responsible for adhesion. FNE and Spy0125 both have a superimposable internal thioester bond between highly conserved Cys and Gln residues. Small-angle X-ray scattering of the FNE-(789) FI complex provided a model that aligns the C-terminal peptide of FNE with the E-strands of the FI domains, adopting the β-zipper extension model observed in previous structures of microbial surface components recognizing adhesive matrix molecule adhesion peptides bound to FI domains.
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Affiliation(s)
- Mounira Tiouajni
- Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619 CNRS, Université Paris Sud, Orsay, France
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Expression of the Streptococcus pneumoniae pilus-1 undergoes on and off switching during colonization in mice. Sci Rep 2014; 3:2040. [PMID: 23784148 PMCID: PMC3687230 DOI: 10.1038/srep02040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 06/04/2013] [Indexed: 12/23/2022] Open
Abstract
Streptococcus pneumoniae pili contribute to adherence and virulence. The regulation of pilus-1 expression is bistable, thus piliated strains contain a variable proportion of pilus-1-non-expressing bacteria. We investigated whether such proportion changes during colonization. Pilus-1-expressing bacteria were quantified in nasopharyngeal washes and pharyngeal tissues from mice that received intranasally bacterial populations with high (H), medium (M) or low (L) pilus-1 expression rates. In nasopharyngeal washes, at early colonization stages, pilus-1 expression rates decreased in H population, while increased in L and M; at later stages, expression rates decreased or remained low. Similar trends were observed in pharyngeal tissues, where, however, at late stages the expression rates were medium-high. In conclusion, pilus-1 is preferentially expressed at early colonization stages, consistently with its role in adhesion, while at later stages the expression is partially switched off. Pilus-1 expression rates observed in clinical isolates in vitro may not reflect the actual rates during colonization/infection.
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Shaik MM, Maccagni A, Tourcier G, Di Guilmi AM, Dessen A. Structural basis of pilus anchoring by the ancillary pilin RrgC of Streptococcus pneumoniae. J Biol Chem 2014; 289:16988-97. [PMID: 24755220 DOI: 10.1074/jbc.m114.555854] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Pili are surface-attached, fibrous virulence factors that play key roles in the pathogenesis process of a number of bacterial agents. Streptococcus pneumoniae is a causative agent of pneumonia and meningitis, and the appearance of drug-resistance organisms has made its treatment challenging, especially in developing countries. Pneumococcus-expressed pili are composed of three structural proteins: RrgB, which forms the polymerized backbone, RrgA, the tip-associated adhesin, and RrgC, which presumably associates the pilus with the bacterial cell wall. Despite the fact that the structures of both RrgA and RrgB were known previously, structural information for RrgC was still lacking, impeding the analysis of a complete model of pilus architecture. Here, we report the structure of RrgC to 1.85 Å and reveal that it is a three-domain molecule stabilized by two intradomain isopeptide bonds. RrgC does not depend on pilus-specific sortases to become attached to the cell wall; instead, it binds the preformed pilus to the peptidoglycan by employing the catalytic activity of SrtA. A comprehensive model of the type 1 pilus from S. pneumoniae is also presented.
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Affiliation(s)
- Md Munan Shaik
- From the Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 41 avenue des Martyrs, 38044 Grenoble, France, the Commissariat à l'Energie Atomique (CEA), 38000 Grenoble, France, the Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France, and
| | - Amandine Maccagni
- From the Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 41 avenue des Martyrs, 38044 Grenoble, France, the Commissariat à l'Energie Atomique (CEA), 38000 Grenoble, France, the Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France, and
| | - Guillaume Tourcier
- From the Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 41 avenue des Martyrs, 38044 Grenoble, France, the Commissariat à l'Energie Atomique (CEA), 38000 Grenoble, France, the Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France, and
| | - Anne Marie Di Guilmi
- From the Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 41 avenue des Martyrs, 38044 Grenoble, France, the Commissariat à l'Energie Atomique (CEA), 38000 Grenoble, France, the Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France, and
| | - Andréa Dessen
- From the Institut de Biologie Structurale (IBS), Université Grenoble Alpes, 41 avenue des Martyrs, 38044 Grenoble, France, the Commissariat à l'Energie Atomique (CEA), 38000 Grenoble, France, the Centre National de la Recherche Scientifique (CNRS), UMR 5075, Grenoble, France, and the Brazilian National Laboratory for Biosciences (LNBio), CNPEM, Campinas, 13083-100 São Paulo, Brazil
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Immune responses to pneumococcal pilus RrgA and RrgB antigens and their relationship with pneumococcal carriage in humans. J Infect 2014; 68:562-71. [PMID: 24509142 DOI: 10.1016/j.jinf.2014.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/17/2014] [Accepted: 01/30/2014] [Indexed: 11/23/2022]
Abstract
OBJECTIVES Pneumococcal pilus antigens are shown to be important in pneumococcal pathogenesis and induce protective immunity in animal studies, but data in humans are limited. We aimed to investigate serum and mucosal immune responses to pilus-1 proteins (RrgA and RrgB) and their relationship with pneumococcal carriage in humans. METHODS Serum and salivary antibodies to RrgA and RrgB in children and adults were analysed by ELISA and immunoblotting. Induction of B cell antibody responses to RrgA and RrgB in nasopharynx-associated lymphoid tissue was studied by ELISpot assay following stimulation with pneumococcal culture supernatants containing pilus proteins. RESULTS Significant levels of serum anti-RrgA and -RrgB antibodies were observed, and anti-RrgA antibody appeared to develop earlier in childhood. Importantly, anti-RrgA IgG titres in both serum and saliva were shown to be higher in culture-negative children than in those who were culture-positive for Streptococcus pneumoniae. Stimulation of adenotonsillar cells with pneumococcal culture supernatant induced significant RrgA- and RrgB-specific antibody secreting cells and antibody production. CONCLUSIONS Pneumococcal pilus antigens, particularly RrgA, seem to induce significant serum and mucosal antibody responses that may contribute to natural immunity against pneumococcal carriage in children.
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Darrieux M, Goulart C, Briles D, Leite LCDC. Current status and perspectives on protein-based pneumococcal vaccines. Crit Rev Microbiol 2013; 41:190-200. [DOI: 10.3109/1040841x.2013.813902] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Delany I, Rappuoli R, Seib KL. Vaccines, reverse vaccinology, and bacterial pathogenesis. Cold Spring Harb Perspect Med 2013; 3:a012476. [PMID: 23637311 DOI: 10.1101/cshperspect.a012476] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Advances in genomics and innovative strategies such as reverse vaccinology have changed the concepts and approaches to vaccine candidate selection and design. Genome mining and blind selection of novel antigens provide a novel route to investigate the mechanisms that underpin pathogenesis. The resulting lists of novel candidates are revealing new aspects of pathogenesis of target organisms, which in turn drives the rational design of optimal vaccine antigens. Here we use the discovery, characterization, and exploitation of fHbp, a vaccine candidate and key virulence factor of meningococcus, as an illustrative case in point. Applying genomic approaches to study both the pathogen and host will ultimately increase our fundamental understanding of pathogen biology, mechanisms responsible for the development of protective immunity, and guide next-generation vaccine design.
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Affiliation(s)
- Isabel Delany
- Novartis Vaccines and Diagnostics, 53100 Siena, Italy
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Olaya-Abril A, Jiménez-Munguía I, Gómez-Gascón L, Rodríguez-Ortega MJ. Surfomics: shaving live organisms for a fast proteomic identification of surface proteins. J Proteomics 2013; 97:164-76. [PMID: 23624344 DOI: 10.1016/j.jprot.2013.03.035] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 02/25/2013] [Accepted: 03/24/2013] [Indexed: 12/11/2022]
Abstract
Surface proteins play a critical role in the interaction between cells and their environment, as they take part in processes like signaling, adhesion, transport, etc. In pathogenic microorganisms, they can also participate in virulence or cytotoxicity. As these proteins have the highest chances to be recognized by the immune system, they are often the targets for the discovery of new vaccines. In addition, they can serve for the development of serological-based tools to diagnose infectious diseases. First-generation proteomic strategies for the identification of surface proteins rely on the biochemical fractionation and/or enrichment of this group of molecules or organelles containing them. However, in the last years, a novel second-generation approach has been developed, consisting of the digestion of live, intact cells with proteases, so that surface-exposed moieties (i.e. the "surfome" of a cell) are "shaved" and analyzed by LC/MS/MS. Here we review such a strategy, firstly set up and developed in Gram-positive bacteria, and further applied to Gram-negative bacteria, unicellular fungi, and also pluricellular organisms. We also discuss the advantages and inconvenients of the approach, and the still unresolved question about the intriguing presence of proteins predicted as cytoplasmic in the surfomes. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.
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Affiliation(s)
- Alfonso Olaya-Abril
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, Córdoba, Spain; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
| | - Irene Jiménez-Munguía
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, Córdoba, Spain; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
| | - Lidia Gómez-Gascón
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, Córdoba, Spain; Departamento de Sanidad Animal, Universidad de Córdoba, Córdoba, Spain
| | - Manuel J Rodríguez-Ortega
- Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Campus de Excelencia Internacional CeiA3, Córdoba, Spain; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain.
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Pilus adhesin RrgA interacts with complement receptor 3, thereby affecting macrophage function and systemic pneumococcal disease. mBio 2012; 4:e00535-12. [PMID: 23269830 PMCID: PMC3531807 DOI: 10.1128/mbio.00535-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Pneumococcal pili have been shown to influence pneumococcal colonization, disease development, and the inflammatory response in mice. The role of the pilus-associated RrgA adhesin in pneumococcal interactions with murine and human macrophages was investigated. Expression of pili with RrgA enhanced the uptake of pneumococci by murine and human macrophages that was abolished by antibodies to complement receptor 3 (CR3) and not seen in CR3-deficient macrophages. Recombinant RrgA, but not pilus subunit RrgC, promoted CR3-mediated phagocytosis of coated beads by murine and human macrophages. Flow cytometry showed that purified CR3 binds pneumococcal cells expressing RrgA, and purified RrgA was shown to interact with CR3 and its I domain. In vivo, RrgA facilitated spread of pneumococci from the upper airways and peritoneal cavity to the bloodstream. Earlier onset of septicemia and more rapidly progressing disease was observed in wild-type mice compared to CR3-deficient mice challenged intranasally or intraperitoneally with pneumococci. Motility assays and time-lapse video microscopy showed that pneumococcal stimulation of macrophage motility required RrgA and CR3. These findings, together with the observed RrgA-dependent increase of intracellular survivors up to 10 h following macrophage infection, suggest that RrgA-CR3-mediated phagocytosis promotes systemic pneumococcal spread from local sites. Streptococcus pneumoniae is a major contributor to morbidity and mortality in infectious diseases globally. Symptomatology is mainly due to pneumococcal interactions with host cells leading to an inflammatory response. However, we still need more knowledge on how pneumococci talk to immune cells and the importance of this interaction. Recently, a novel structure was identified on the pneumococcal surface, an adhesive pilus found in about 30% of clinical pneumococcal isolates. The pilus has been suggested to be important for successful spread of antibiotic-resistant pneumococcal clones globally. Here we sought to identify mechanisms for how the pneumococcal pilin subunit RrgA contributes to disease development by interacting with host immune cells. Our data suggest a new way for how pneumococci may cross talk with phagocytic cells and affect disease progression. An increased understanding of these processes may lead to better strategies for how to treat these common infections.
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50
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Oxaran V, Ledue-Clier F, Dieye Y, Herry JM, Péchoux C, Meylheuc T, Briandet R, Juillard V, Piard JC. Pilus biogenesis in Lactococcus lactis: molecular characterization and role in aggregation and biofilm formation. PLoS One 2012; 7:e50989. [PMID: 23236417 PMCID: PMC3516528 DOI: 10.1371/journal.pone.0050989] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 10/29/2012] [Indexed: 02/07/2023] Open
Abstract
The genome of Lactococcus lactis strain IL1403 harbors a putative pilus biogenesis cluster consisting of a sortase C gene flanked by 3 LPxTG protein encoding genes (yhgD, yhgE, and yhhB), called here pil. However, pili were not detected under standard growth conditions. Over-expression of the pil operon resulted in production and display of pili on the surface of lactococci. Functional analysis of the pilus biogenesis machinery indicated that the pilus shaft is formed by oligomers of the YhgE pilin, that the pilus cap is formed by the YhgD pilin and that YhhB is the basal pilin allowing the tethering of the pilus fibers to the cell wall. Oligomerization of pilin subunits was catalyzed by sortase C while anchoring of pili to the cell wall was mediated by sortase A. Piliated L. lactis cells exhibited an auto-aggregation phenotype in liquid cultures, which was attributed to the polymerization of major pilin, YhgE. The piliated lactococci formed thicker, more aerial biofilms compared to those produced by non-piliated bacteria. This phenotype was attributed to oligomers of YhgE. This study provides the first dissection of the pilus biogenesis machinery in a non-pathogenic Gram-positive bacterium. Analysis of natural lactococci isolates from clinical and vegetal environments showed pili production under standard growth conditions. The identification of functional pili in lactococci suggests that the changes they promote in aggregation and biofilm formation may be important for the natural lifestyle as well as for applications in which these bacteria are used.
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Affiliation(s)
- Virginie Oxaran
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | - Florence Ledue-Clier
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | - Yakhya Dieye
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | - Jean-Marie Herry
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | | | - Thierry Meylheuc
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | - Romain Briandet
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | - Vincent Juillard
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
| | - Jean-Christophe Piard
- INRA, UMR1319 Micalis, Domaine de Vilvert, Jouy-en-Josas, France
- Agro ParisTech, UMR 1319 Micalis, Jouy-en-Josas, France
- * E-mail:
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