1
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Prajapati A, Palva A, von Ossowski I, Krishnan V. The crystal structure of the N-terminal domain of the backbone pilin LrpA reveals a new closure-and-twist motion for assembling dynamic pili in Ligilactobacillus ruminis. Acta Crystallogr D Struct Biol 2024; 80:474-492. [PMID: 38935340 DOI: 10.1107/s2059798324005114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/30/2024] [Indexed: 06/28/2024] Open
Abstract
Sortase-dependent pili are long surface appendages that mediate attachment, colonization and biofilm formation in certain genera and species of Gram-positive bacteria. Ligilactobacillus ruminis is an autochthonous gut commensal that relies on sortase-dependent LrpCBA pili for host adherence and persistence. X-ray crystal structure snapshots of the backbone pilin LrpA were captured in two atypical bent conformations leading to a zigzag morphology in the LrpCBA pilus structure. Small-angle X-ray scattering and structural analysis revealed that LrpA also adopts the typical linear conformation, resulting in an elongated pilus morphology. Various conformational analyses and biophysical experiments helped to demonstrate that a hinge region located at the end of the flexible N-terminal domain of LrpA facilitates a new closure-and-twist motion for assembling dynamic pili during the assembly process and host attachment. Further, the incongruent combination of flexible domain-driven conformational dynamics and rigid isopeptide bond-driven stability observed in the LrpCBA pilus might also extend to the sortase-dependent pili of other bacteria colonizing a host.
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Affiliation(s)
- Amar Prajapati
- Laboratory of Structural Microbiology, 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 Microbiology, Regional Centre for Biotechnology, NCR, Biotech Science Cluster, Faridabad 121 001, India
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2
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Little JI, Singh PK, Zhao J, Dunn S, Matz H, Donnenberg MS. Type IV pili of Enterobacteriaceae species. EcoSal Plus 2024:eesp00032023. [PMID: 38294234 DOI: 10.1128/ecosalplus.esp-0003-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 12/01/2023] [Indexed: 02/01/2024]
Abstract
Type IV pili (T4Ps) are surface filaments widely distributed among bacteria and archaea. T4Ps are involved in many cellular functions and contribute to virulence in some species of bacteria. Due to the diversity of T4Ps, different properties have been observed for homologous proteins that make up T4Ps in various organisms. In this review, we highlight the essential components of T4Ps, their functions, and similarities to related systems. We emphasize the unique T4Ps of enteric pathogens within the Enterobacteriaceae family, which includes pathogenic strains of Escherichia coli and Salmonella. These include the bundle-forming pilus (BFP) of enteropathogenic E. coli (EPEC), longus (Lng) and colonization factor III (CFA/III) of enterotoxigenic E. coli (ETEC), T4P of Salmonella enterica serovar Typhi, Colonization Factor Citrobacter (CFC) of Citrobacter rodentium, T4P of Yersinia pseudotuberculosis, a ubiquitous T4P that was characterized in enterohemorrhagic E. coli (EHEC), and the R64 plasmid thin pilus. Finally, we highlight areas for further study.
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Affiliation(s)
- Janay I Little
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Pradip K Singh
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Jinlei Zhao
- School of Medicine, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Shakeera Dunn
- Internal Medicine Residency, Bayhealth Medical Center, Dover, Delaware, USA
| | - Hanover Matz
- Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
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3
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Sue CK, Cheung NA, Mahoney BJ, McConnell SA, Scully JM, Fu JY, Chang C, Ton-That H, Loo JA, Clubb RT. The basal and major pilins in the Corynebacterium diphtheriae SpaA pilus adopt similar structures that competitively react with the pilin polymerase. Biopolymers 2024; 115:e23539. [PMID: 37227047 PMCID: PMC11164409 DOI: 10.1002/bip.23539] [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: 01/31/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/26/2023]
Abstract
Many species of pathogenic gram-positive bacteria display covalently crosslinked protein polymers (called pili or fimbriae) that mediate microbial adhesion to host tissues. These structures are assembled by pilus-specific sortase enzymes that join the pilin components together via lysine-isopeptide bonds. The archetypal SpaA pilus from Corynebacterium diphtheriae is built by the Cd SrtA pilus-specific sortase, which crosslinks lysine residues within the SpaA and SpaB pilins to build the shaft and base of the pilus, respectively. Here, we show that Cd SrtA crosslinks SpaB to SpaA via a K139(SpaB)-T494(SpaA) lysine-isopeptide bond. Despite sharing only limited sequence homology, an NMR structure of SpaB reveals striking similarities with the N-terminal domain of SpaA (N SpaA) that is also crosslinked by Cd SrtA. In particular, both pilins contain similarly positioned reactive lysine residues and adjacent disordered AB loops that are predicted to be involved in the recently proposed "latch" mechanism of isopeptide bond formation. Competition experiments using an inactive SpaB variant and additional NMR studies suggest that SpaB terminates SpaA polymerization by outcompeting N SpaA for access to a shared thioester enzyme-substrate reaction intermediate.
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Affiliation(s)
- Christopher K. Sue
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
| | - Nicole A. Cheung
- UCLA-DOE Institute for Genomics and Proteomics
- Molecular Biology Institute
| | - Brendan J. Mahoney
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
| | - Scott A. McConnell
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
| | - Jack M. Scully
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
| | - Janine Y. Fu
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
| | - Chungyu Chang
- Molecular Biology Institute
- Division of Oral and Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Hung Ton-That
- Molecular Biology Institute
- Division of Oral and Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
- Molecular Biology Institute
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry
- UCLA-DOE Institute for Genomics and Proteomics
- Molecular Biology Institute
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4
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Young PG, Paynter JM, Wardega JK, Middleditch MJ, Payne LS, Baker EN, Squire CJ. Domain structure and cross-linking in a giant adhesin from the Mobiluncus mulieris bacterium. Acta Crystallogr D Struct Biol 2023; 79:971-979. [PMID: 37860959 PMCID: PMC10619420 DOI: 10.1107/s2059798323007507] [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: 06/16/2023] [Accepted: 08/27/2023] [Indexed: 10/21/2023] Open
Abstract
Cell-surface proteins known as adhesins enable bacteria to colonize particular environments, and in Gram-positive bacteria often contain autocatalytically formed covalent intramolecular cross-links. While investigating the prevalence of such cross-links, a remarkable example was discovered in Mobiluncus mulieris, a pathogen associated with bacterial vaginosis. This organism encodes a putative adhesin of 7651 residues. Crystallography and mass spectrometry of two selected domains, and AlphaFold structure prediction of the remainder of the protein, were used to show that this adhesin belongs to the family of thioester, isopeptide and ester-bond-containing proteins (TIE proteins). It has an N-terminal domain homologous to thioester adhesion domains, followed by 51 immunoglobulin (Ig)-like domains containing ester- or isopeptide-bond cross-links. The energetic cost to the M. mulieris bacterium in retaining such a large adhesin as a single gene or protein construct suggests a critical role in pathogenicity and/or persistence.
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Affiliation(s)
- Paul G. Young
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, c/o The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Jacob M. Paynter
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Julia K. Wardega
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Martin J. Middleditch
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Leo S. Payne
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Edward N. Baker
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, c/o The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Christopher J. Squire
- School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, c/o The University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
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5
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Gaines MC, Isupov MN, Sivabalasarma S, Haque RU, McLaren M, Mollat CL, Tripp P, Neuhaus A, Gold VAM, Albers SV, Daum B. Electron cryo-microscopy reveals the structure of the archaeal thread filament. Nat Commun 2022; 13:7411. [PMID: 36456543 PMCID: PMC9715654 DOI: 10.1038/s41467-022-34652-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 11/02/2022] [Indexed: 12/05/2022] Open
Abstract
Pili are filamentous surface extensions that play roles in bacterial and archaeal cellular processes such as adhesion, biofilm formation, motility, cell-cell communication, DNA uptake and horizontal gene transfer. The model archaeaon Sulfolobus acidocaldarius assembles three filaments of the type-IV pilus superfamily (archaella, archaeal adhesion pili and UV-inducible pili), as well as a so-far uncharacterised fourth filament, named "thread". Here, we report on the cryo-EM structure of the archaeal thread. The filament is highly glycosylated and consists of subunits of the protein Saci_0406, arranged in a head-to-tail manner. Saci_0406 displays structural similarity, but low sequence homology, to bacterial type-I pilins. Thread subunits are interconnected via donor strand complementation, a feature reminiscent of bacterial chaperone-usher pili. However, despite these similarities in overall architecture, archaeal threads appear to have evolved independently and are likely assembled by a distinct mechanism.
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Affiliation(s)
- Matthew C Gaines
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, Stocker Road, EX4 4QD, Exeter, UK
| | - Michail N Isupov
- Henry Wellcome Building for Biocatalysis, Department of Biosciences, Faculty of Health and Life Sciences, University of Exeter, EX4 4QD, Exeter, UK
| | - Shamphavi Sivabalasarma
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
| | - Risat Ul Haque
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, Stocker Road, EX4 4QD, Exeter, UK
| | - Mathew McLaren
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, Stocker Road, EX4 4QD, Exeter, UK
| | - Clara L Mollat
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
| | - Patrick Tripp
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
| | - Alexander Neuhaus
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, Stocker Road, EX4 4QD, Exeter, UK
| | - Vicki A M Gold
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK
- Department of Biosciences, Faculty of Health and Life Sciences, Stocker Road, EX4 4QD, Exeter, UK
| | - Sonja-Verena Albers
- Institute of Biology II, Molecular Biology of Archaea, University of Freiburg, Schänzlestraße 1, 79104, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, University of Freiburg, Freiburg, Germany
- Signalling Research Centres BIOSS and CIBBS, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Bertram Daum
- Living Systems Institute, University of Exeter, Stocker Road, EX4 4QD, Exeter, UK.
- Department of Biosciences, Faculty of Health and Life Sciences, Stocker Road, EX4 4QD, Exeter, UK.
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6
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Yadav RK, Krishnan V. New structural insights into the
PI
‐2 pilus from
Streptococcus oralis
, an early dental plaque colonizer. FEBS J 2022; 289:6342-6366. [DOI: 10.1111/febs.16527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 04/20/2022] [Accepted: 05/10/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Rajnesh Kumari Yadav
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology NCR Biotech Science Cluster Faridabad India
- School of Biotechnology KIIT University Odisha India
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology NCR Biotech Science Cluster Faridabad India
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7
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Zegeye ED, Pradhan B, Llarena AK, Aspholm M. Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species. Int J Mol Sci 2021; 22:12367. [PMID: 34830248 PMCID: PMC8619143 DOI: 10.3390/ijms222212367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/11/2021] [Accepted: 11/12/2021] [Indexed: 11/16/2022] Open
Abstract
The endospores (spores) of many Bacillus cereus sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience to proteolytic digestion and chemical solubilization. A recent structural analysis of B. cereus endospore appendages (Enas) using cryo-electron microscopy has revealed the structure of two distinct fiber morphologies: the longer and more abundant "Staggered-type" (S-Ena) and the shorter "Ladder-like" type (L-Ena), which further enabled the identification of the genes encoding the S-Ena. Ena homologs are widely and uniquely distributed among B. cereus sensu lato species, suggesting that appendages play important functional roles in these species. The discovery of ena genes is expected to facilitate functional studies involving Ena-depleted mutant spores to explore the role of Enas in the interaction between spores and their environment. Given the importance of B. cereus spores for the food industry and in medicine, there is a need for a better understanding of their biological functions and physicochemical properties. In this review, we discuss the current understanding of the Ena structure and the potential roles these remarkable fibers may play in the adhesion of spores to biotic and abiotic surfaces, aggregation, and biofilm formation.
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Affiliation(s)
- Ephrem Debebe Zegeye
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway; (E.D.Z.); (A.-K.L.)
| | - Brajabandhu Pradhan
- Structural and Molecular Microbiology, VIB-VUB Center for Structural Biology, VIB, 1050 Brussels, Belgium;
- Department of Bioengineering Sciences, Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Ann-Katrin Llarena
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway; (E.D.Z.); (A.-K.L.)
| | - Marina Aspholm
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway; (E.D.Z.); (A.-K.L.)
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8
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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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9
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Crystallization of Recombinant Fimbrial Proteins of Porphyromonas gingivalis. Methods Mol Biol 2020. [PMID: 32815130 DOI: 10.1007/978-1-0716-0939-2_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Porphyromonas gingivalis fimbriae play a critical role in colonization. Elucidation of the fimbrial structure in atomic detail is important for understanding the colonization mechanism and to provide means to combat periodontitis. X-ray crystallography is a technique that is used to obtain detailed information of proteins along with bound ligands and ions. Crystallization of the protein of interest is the first step toward structure determination. Unfortunately it is not possible to predict the crystallization condition of a certain protein or even if the protein can be crystallized. Protein crystallization is, on the contrary, a matter of trial and error. However, the best strategy for success is to focus on the protein purification step to obtain a sample that is pure, stable, homogeneous and of high concentration. This chapter addresses general methods for crystallization of fimbrial proteins.
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10
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Tamai E, Katayama S, Sekiya H, Nariya H, Kamitori S. Structures of major pilins in Clostridium perfringens demonstrate dynamic conformational change. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:718-732. [PMID: 31373571 DOI: 10.1107/s2059798319009689] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022]
Abstract
Pili in Gram-positive bacteria are flexible rod proteins associated with the bacterial cell surface, and they play important roles in the initial adhesion to host tissues and colonization. The pilus shaft is formed by the covalent polymerization of major pilins, catalyzed by sortases, a family of cysteine transpeptidases. Here, X-ray structures of the major pilins from Clostridium perfringens strains 13 and SM101 and of sortase from strain SM101 are presented with biochemical analysis to detect the formation of pili in vivo. The major pilin from strain 13 adopts an elongated structure to form noncovalently linked polymeric chains in the crystal, yielding a practical model of the pilus fiber structure. The major pilin from strain SM101 adopts a novel bent structure and associates to form a left-handed twist like an antiparallel double helix in the crystal, which is likely to promote bacterial cell-cell interactions. A modeling study showed that pilin with a bent structure interacts favorably with sortase. The major pilin from strain SM101 was considered to be in an equilibrium state between an elongated and a bent structure through dynamic conformational change, which may be involved in pili-mediated colonization and sortase-mediated polymerization of pili.
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Affiliation(s)
- Eiji Tamai
- Department of Infectious Disease, College of Pharmaceutical Science, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime 790-8578, Japan
| | - Seiichi Katayama
- Department of Life Science, Faculty of Science, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005, Japan
| | - Hiroshi Sekiya
- Department of Infectious Disease, College of Pharmaceutical Science, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime 790-8578, Japan
| | - Hirofumi Nariya
- Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama-cho, Higashihiroshima, Hiroshima 739-8528, Japan
| | - Shigehiro Kamitori
- Life Science Research Center and Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793, Japan
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11
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Chaurasia P, Pratap S, Palva A, von Ossowski I, Krishnan V. Bent conformation of a backbone pilin N-terminal domain supports a three-stage pilus assembly mechanism. Commun Biol 2018; 1:94. [PMID: 30271975 PMCID: PMC6123636 DOI: 10.1038/s42003-018-0100-0] [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] [Received: 02/01/2018] [Accepted: 06/21/2018] [Indexed: 12/31/2022] Open
Abstract
Effective colonization of host cells by some Gram-positive bacteria often involves using lengthy, adhesive macromolecular structures called sortase-dependent pili. Among commensals, the gut-adapted Lactobacillus rhamnosus GG strain encodes the operons for two varieties of these pili (SpaCBA and SpaFED), with each structure consisting of backbone, tip, and basal pilin subunits. Although the tertiary structure was recently solved for the backbone subunit (SpaA) of the SpaCBA pilus, no structural information exists for its counterpart in the SpaFED pilus. Here, we report several crystal structures for the SpaD backbone pilin, two of which capture the N-terminal domain in either the closed (linear) or open (bent) conformation. To our knowledge, this is the first observation of the bent conformation in Gram-positive pilin structures. Based on this bent conformation, we suggest a three-stage model, which we call the expose-ligate-seal mechanism, for the docking and assembly of backbone pilins into the sortase-dependent pilus. Priyanka Chaurasia et al. report crystal structures of the SpaD backbone pilin from a gut-adapted bacteria, Lactobacillus rhamnosus. The observed bent conformation of the N-terminal domain has not been seen in other Gram-positive pilin structures.
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Affiliation(s)
- Priyanka Chaurasia
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India.,Department of Biotechnology, Manipal University, Manipal, Karnataka, 576104, India
| | - Shivendra Pratap
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India
| | - Airi Palva
- Department of Veterinary Biosciences, University of Helsinki, FIN-00014, Helsinki, Finland
| | - Ingemar von Ossowski
- Department of Veterinary Biosciences, University of Helsinki, FIN-00014, Helsinki, Finland
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121001, India.
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12
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Frohnmeyer E, Deptula P, Nyman TA, Laine PKS, Vihinen H, Paulin L, Auvinen P, Jokitalo E, Piironen V, Varmanen P, Savijoki K. Secretome profiling of Propionibacterium freudenreichii reveals highly variable responses even among the closely related strains. Microb Biotechnol 2018; 11:510-526. [PMID: 29488359 PMCID: PMC5902329 DOI: 10.1111/1751-7915.13254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 01/19/2018] [Indexed: 12/20/2022] Open
Abstract
This study compared the secretomes (proteins exported out of the cell) of Propionibacterium freudenreichii of different origin to identify plausible adaptation factors. Phylosecretomics indicated strain‐specific variation in secretion of adhesins/invasins (SlpA, InlA), cell‐wall hydrolysing (NlpC60 peptidase, transglycosylase), protective (RpfB) and moonlighting (DnaK, GroEL, GaPDH, IDH, ENO, ClpB) enzymes and/or proteins. Detailed secretome comparison suggested that one of the cereal strains (JS14) released a tip fimbrillin (FimB) in to the extracellular milieu, which was in line with the electron microscopy and genomic analyses, indicating the lack of surface‐associated fimbrial‐like structures, predicting a mutated type‐2 fimbrial gene cluster (fimB‐fimA‐srtC2) and production of anchorless FimB. Instead, the cereal strain produced high amounts of SlpB that tentatively mediated adherent growth on hydrophilic surface and adherence to hydrophobic material. One of the dairy strains (JS22), producing non‐covalently bound surface‐proteins (LspA, ClpB, AraI) and releasing SlpA and InlA into the culture medium, was found to form clumps under physiological conditions. The JS22 strain lacked SlpB and displayed a non‐clumping and biofilm‐forming phenotype only under conditions of increased ionic strength (300 mM NaCl). However, this strain cultured under the same conditions was not adherent to hydrophobic support, which supports the contributory role of SlpB in mediating hydrophobic interactions. Thus, this study reports significant secretome variation in P. freudenreichii and suggests that strain‐specific differences in protein export, modification and protein–protein interactions have been the driving forces behind the adaptation of this bacterial species.
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Affiliation(s)
- Esther Frohnmeyer
- Department of Food and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
| | - Paulina Deptula
- Department of Food and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
| | - Tuula A Nyman
- Department of Immunology, Institute of Clinical Medicine, University of Oslo, 0424 Oslo, Norway
| | - Pia K S Laine
- DNA Sequencing and Genomics Lab, Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Helena Vihinen
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Lars Paulin
- DNA Sequencing and Genomics Lab, Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Petri Auvinen
- DNA Sequencing and Genomics Lab, Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Eija Jokitalo
- Electron Microscopy Unit, Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Vieno Piironen
- Department of Food and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
| | - Pekka Varmanen
- Department of Food and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
| | - Kirsi Savijoki
- Department of Food and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
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13
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Kwon H, Young PG, Squire CJ, Baker EN. Engineering a Lys-Asn isopeptide bond into an immunoglobulin-like protein domain enhances its stability. Sci Rep 2017; 7:42753. [PMID: 28202898 PMCID: PMC5311914 DOI: 10.1038/srep42753] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 01/11/2017] [Indexed: 11/15/2022] Open
Abstract
The overall stability of globular protein structures is marginal, a balance between large numbers of stabilizing non-covalent interactions and a destabilizing entropic term. Higher stability can be engineered by introduction of disulfide bonds, provided the redox environment is controlled. The discovery of stabilizing isopeptide bond crosslinks, formed spontaneously between lysine and asparagine (or aspartic acid) side chains in certain bacterial cell-surface proteins suggests that such bonds could be introduced by protein engineering as an alternative protein stabilization strategy. We report the first example of an isopeptide bond engineered de novo into an immunoglobulin-like protein, the minor pilin FctB from Streptococcus pyogenes. Four mutations were sufficient; lysine, asparagine and glutamic acid residues were introduced for the bond-forming reaction, with a fourth Val/Phe mutation to help steer the lysine side chain into position. The spontaneously-formed isopeptide bond was confirmed by mass spectrometry and X-ray crystallography, and was shown to increase the thermal stability by 10 °C compared with the wild type protein. This novel method for increasing the stability of IgG-like proteins has potential to be adopted by the field of antibody engineering, which share similar β-clasp Ig-type domains.
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Affiliation(s)
- Hanna Kwon
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Paul G Young
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Christopher J Squire
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Edward N Baker
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
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14
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Abstract
Disulfide bonds are important for the stability and function of many secreted proteins. In Gram-negative bacteria, these linkages are catalyzed by thiol-disulfide oxidoreductases (Dsb) in the periplasm. Protein oxidation has been well studied in these organisms, but it has not fully been explored in Gram-positive bacteria, which lack traditional periplasmic compartments. Recent bioinformatics analyses have suggested that the high-GC-content bacteria (i.e., actinobacteria) rely on disulfide-bond-forming pathways. In support of this, Dsb-like proteins have been identified in Mycobacterium tuberculosis, but their functions are not known. Actinomyces oris and Corynebacterium diphtheriae have recently emerged as models to study disulfide bond formation in actinobacteria. In both organisms, disulfide bonds are catalyzed by the membrane-bound oxidoreductase MdbA. Remarkably, unlike known Dsb proteins, MdbA is important for pathogenesis and growth, which makes it a potential target for new antibacterial drugs. This review will discuss disulfide-bond-forming pathways in bacteria, with a special focus on Gram-positive bacteria.
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15
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Self-generated covalent cross-links in the cell-surface adhesins of Gram-positive bacteria. Biochem Soc Trans 2015; 43:787-94. [DOI: 10.1042/bst20150066] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The ability of bacteria to adhere to other cells or to surfaces depends on long, thin adhesive structures that are anchored to their cell walls. These structures include extended protein oligomers known as pili and single, multi-domain polypeptides, mostly based on multiple tandem Ig-like domains. Recent structural studies have revealed the widespread presence of covalent cross-links, not previously seen within proteins, which stabilize these domains. The cross-links discovered so far are either isopeptide bonds that link lysine side chains to the side chains of asparagine or aspartic acid residues or ester bonds between threonine and glutamine side chains. These bonds appear to be formed by spontaneous intramolecular reactions as the proteins fold and are strategically placed so as to impart considerable mechanical strength.
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16
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Reardon-Robinson ME, Osipiuk J, Chang C, Wu C, Jooya N, Joachimiak A, Das A, Ton-That H. A Disulfide Bond-forming Machine Is Linked to the Sortase-mediated Pilus Assembly Pathway in the Gram-positive Bacterium Actinomyces oris. J Biol Chem 2015; 290:21393-405. [PMID: 26170452 PMCID: PMC4571867 DOI: 10.1074/jbc.m115.672253] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Indexed: 12/30/2022] Open
Abstract
Export of cell surface pilins in Gram-positive bacteria likely occurs by the translocation of unfolded precursor polypeptides; however, how the unfolded pilins gain their native conformation is presently unknown. Here, we present physiological studies to demonstrate that the FimA pilin of Actinomyces oris contains two disulfide bonds. Alanine substitution of cysteine residues forming the C-terminal disulfide bridge abrogates pilus assembly, in turn eliminating biofilm formation and polymicrobial interaction. Transposon mutagenesis of A. oris yielded a mutant defective in adherence to Streptococcus oralis, and revealed the essential role of a vitamin K epoxide reductase (VKOR) gene in pilus assembly. Targeted deletion of vkor results in the same defects, which are rescued by ectopic expression of VKOR, but not a mutant containing an alanine substitution in its conserved CXXC motif. Depletion of mdbA, which encodes a membrane-bound thiol-disulfide oxidoreductase, abrogates pilus assembly and alters cell morphology. Remarkably, overexpression of MdbA or a counterpart from Corynebacterium diphtheriae, rescues the Δvkor mutant. By alkylation assays, we demonstrate that VKOR is required for MdbA reoxidation. Furthermore, crystallographic studies reveal that A. oris MdbA harbors a thioredoxin-like fold with the conserved CXXC active site. Consistently, each MdbA enzyme catalyzes proper disulfide bond formation within FimA in vitro that requires the catalytic CXXC motif. Because the majority of signal peptide-containing proteins encoded by A. oris possess multiple Cys residues, we propose that MdbA and VKOR constitute a major folding machine for the secretome of this organism. This oxidative protein folding pathway may be a common feature in Actinobacteria.
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Affiliation(s)
- Melissa E. Reardon-Robinson
- From the Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030
| | - Jerzy Osipiuk
- the Department of Biosciences, Midwest Center for Structural Genomics, and ,the Department of Biosciences, Structural Biology Center, Argonne National Laboratory, Argonne, Illinois 60439, and
| | - Chungyu Chang
- From the Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030
| | - Chenggang Wu
- From the Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030
| | - Neda Jooya
- From the Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030
| | - Andrzej Joachimiak
- the Department of Biosciences, Midwest Center for Structural Genomics, and ,the Department of Biosciences, Structural Biology Center, Argonne National Laboratory, Argonne, Illinois 60439, and
| | - Asis Das
- the Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut 06030
| | - Hung Ton-That
- From the Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, Texas 77030,
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17
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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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18
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Cozzi R, Malito E, Lazzarin M, Nuccitelli A, Castagnetti A, Bottomley MJ, Margarit I, Maione D, Rinaudo CD. Structure and assembly of group B streptococcus pilus 2b backbone protein. PLoS One 2015; 10:e0125875. [PMID: 25942637 PMCID: PMC4420484 DOI: 10.1371/journal.pone.0125875] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 03/26/2015] [Indexed: 12/03/2022] Open
Abstract
Group B Streptococcus (GBS) is a major cause of invasive disease in infants. Like other Gram-positive bacteria, GBS uses a sortase C-catalyzed transpeptidation mechanism to generate cell surface pili from backbone and ancillary pilin precursor substrates. The three pilus types identified in GBS contain structural subunits that are highly immunogenic and are promising candidates for the development of a broadly-protective vaccine. Here we report the X-ray crystal structure of the backbone protein of pilus 2b (BP-2b) at 1.06Å resolution. The structure reveals a classical IgG-like fold typical of the pilin subunits of other Gram-positive bacteria. The crystallized portion of the protein (residues 185-468) encompasses domains D2 and D3 that together confer high stability to the protein due to the presence of an internal isopeptide bond within each domain. The D2+D3 region, lacking the N-terminal D1 domain, was as potent as the entire protein in conferring protection against GBS challenge in a well-established mouse model. By site-directed mutagenesis and complementation studies in GBS knock-out strains we identified the residues and motives essential for assembly of the BP-2b monomers into high-molecular weight complexes, thus providing new insights into pilus 2b polymerization.
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19
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Kang HJ, Paterson NG, Kim CU, Middleditch M, Chang C, Ton-That H, Baker EN. A slow-forming isopeptide bond in the structure of the major pilin SpaD from Corynebacterium diphtheriae has implications for pilus assembly. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:1190-201. [PMID: 24816089 PMCID: PMC4014117 DOI: 10.1107/s1399004714001400] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 01/20/2014] [Indexed: 12/04/2022]
Abstract
The Gram-positive organism Corynebacterium diphtheriae, the cause of diphtheria in humans, expresses pili on its surface which it uses for adhesion and colonization of its host. These pili are covalent protein polymers composed of three types of pilin subunit that are assembled by specific sortase enzymes. A structural analysis of the major pilin SpaD, which forms the polymeric backbone of one of the three types of pilus expressed by C. diphtheriae, is reported. Mass-spectral and crystallographic analysis shows that SpaD contains three internal Lys-Asn isopeptide bonds. One of these, shown by mass spectrometry to be located in the N-terminal D1 domain of the protein, only forms slowly, implying an energy barrier to bond formation. Two crystal structures, of the full-length three-domain protein at 2.5 Å resolution and of a two-domain (D2-D3) construct at 1.87 Å resolution, show that each of the three Ig-like domains contains a single Lys-Asn isopeptide-bond cross-link, assumed to give mechanical stability as in other such pili. Additional stabilizing features include a disulfide bond in the D3 domain and a calcium-binding loop in D2. The N-terminal D1 domain is more flexible than the others and, by analogy with other major pilins of this type, the slow formation of its isopeptide bond can be attributed to its location adjacent to the lysine used in sortase-mediated polymerization during pilus assembly.
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Affiliation(s)
- Hae Joo Kang
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Neil G. Paterson
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Chae Un Kim
- Cornell High Energy Synchrotron Source and Macromolecular Diffraction Facility at CHESS (MacCHESS), Cornell University, Ithaca, NY 14853, USA
| | - Martin Middleditch
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Chungyu Chang
- Department of Microbiology and Molecular Genetics, University of Texas–Houston Medical School, Houston, TX 77030, USA
| | - Hung Ton-That
- Department of Microbiology and Molecular Genetics, University of Texas–Houston Medical School, Houston, TX 77030, USA
| | - Edward N. Baker
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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20
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Structural conservation, variability, and immunogenicity of the T6 backbone pilin of serotype M6 Streptococcus pyogenes. Infect Immun 2014; 82:2949-57. [PMID: 24778112 DOI: 10.1128/iai.01706-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group A streptococcus (GAS; Streptococcus pyogenes) is a Gram-positive human pathogen that causes a broad range of diseases ranging from acute pharyngitis to the poststreptococcal sequelae of acute rheumatic fever. GAS pili are highly diverse, long protein polymers that extend from the cell surface. They have multiple roles in infection and are promising candidates for vaccine development. This study describes the structure of the T6 backbone pilin (BP; Lancefield T-antigen) from the important M6 serotype. The structure reveals a modular arrangement of three tandem immunoglobulin-like domains, two with internal isopeptide bonds. The T6 pilin lysine, essential for polymerization, is located in a novel VAKS motif that is structurally homologous to the canonical YPKN pilin lysine in other three- and four-domain Gram-positive pilins. The T6 structure also highlights a conserved pilin core whose surface is decorated with highly variable loops and extensions. Comparison to other Gram-positive BPs shows that many of the largest variable extensions are found in conserved locations. Studies with sera from patients diagnosed with GAS-associated acute rheumatic fever showed that each of the three T6 domains, and the largest of the variable extensions (V8), are targeted by IgG during infection in vivo. Although the GAS BP show large variations in size and sequence, the modular nature of the pilus proteins revealed by the T6 structure may aid the future design of a pilus-based vaccine.
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21
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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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22
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Hall M, Nylander S, Jenkinson HF, Persson K. Structure of the C-terminal domain of AspA (antigen I/II-family) protein from Streptococcus pyogenes. FEBS Open Bio 2014; 4:283-9. [PMID: 24918040 PMCID: PMC4048849 DOI: 10.1016/j.fob.2014.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/27/2014] [Accepted: 02/28/2014] [Indexed: 01/01/2023] Open
Abstract
The structure of the C2–3-domain of AspA from S. pyogenes was determined. The C2 and C3 domains both adopt DEv-IgG folds. Conserved isopeptide bonds and calcium binding sites are observed. Distinct structural features are observed in the SspB Adherence Region (BAR).
The pathogenic bacteria Streptococcus pyogenes can cause an array of diseases in humans, including moderate infections such as pharyngitis (strep throat) as well as life threatening conditions such as necrotizing fasciitis and puerperal fever. The antigen I/II family proteins are cell wall anchored adhesin proteins found on the surfaces of most oral streptococci and are involved in host colonization and biofilm formation. In the present study we have determined the crystal structure of the C2–3-domain of the antigen I/II type protein AspA from S. pyogenes M type 28. The structure was solved to 1.8 Å resolution and shows that the C2–3-domain is comprised of two structurally similar DEv-IgG motifs, designated C2 and C3, both containing a stabilizing covalent isopeptide bond. Furthermore a metal binding site is identified, containing a bound calcium ion. Despite relatively low sequence identity, interestingly, the overall structure shares high similarity to the C2–3-domains of antigen I/II proteins from Streptococcus gordonii and Streptococcus mutans, although certain parts of the structure exhibit distinct features. In summary this work constitutes the first step in the full structure determination of the AspA protein from S. pyogenes.
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Affiliation(s)
- Michael Hall
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Sa Nylander
- Department of Odontology, Division of Oral Microbiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Howard F Jenkinson
- School of Oral and Dental Sciences, University of Bristol, Bristol BS1 2LY, UK
| | - Karina Persson
- Department of Chemistry, Umeå University, SE-901 87 Umeå, Sweden
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