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Saran A, Kim HM, Manning I, Hancock MA, Schmitz C, Madej M, Potempa J, Sola M, Trempe JF, Zhu Y, Davey ME, Zeytuni N. Unveiling the molecular mechanisms of the type IX secretion system's response regulator: Structural and functional insights. PNAS NEXUS 2024; 3:pgae316. [PMID: 39139265 PMCID: PMC11320123 DOI: 10.1093/pnasnexus/pgae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 07/22/2024] [Indexed: 08/15/2024]
Abstract
The type IX secretion system (T9SS) is a nanomachinery utilized by bacterial pathogens to facilitate infection. The system is regulated by a signaling cascade serving as its activation switch. A pivotal member in this cascade, the response regulator protein PorX, represents a promising drug target to prevent the secretion of virulence factors. Here, we provide a comprehensive characterization of PorX both in vitro and in vivo. First, our structural studies revealed PorX harbors a unique enzymatic effector domain, which, surprisingly, shares structural similarities with the alkaline phosphatase superfamily, involved in nucleotide and lipid signaling pathways. Importantly, such pathways have not been associated with the T9SS until now. Enzymatic characterization of PorX's effector domain revealed a zinc-dependent phosphodiesterase activity, with active site dimensions suitable to accommodate a large substrate. Unlike typical response regulators that dimerize via their receiver domain upon phosphorylation, we found that zinc can also induce conformational changes and promote PorX's dimerization via an unexpected interface. These findings suggest that PorX can serve as a cellular zinc sensor, broadening our understanding of its regulatory mechanisms. Despite the strict conservation of PorX in T9SS-utilizing bacteria, we demonstrate that PorX is essential for virulence factors secretion in Porphyromonas gingivalis and affects metabolic enzymes secretion in the nonpathogenic Flavobacterium johnsoniae, but not for the secretion of gliding adhesins. Overall, this study advances our structural and functional understanding of PorX, highlighting its potential as a druggable target for intervention strategies aimed at disrupting the T9SS and mitigating virulence in pathogenic species.
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Affiliation(s)
- Anshu Saran
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
| | - Hey-Min Kim
- Department of Microbiology, The Forsyth Institute, 245 First St, Cambridge, MA 02142, USA
| | - Ireland Manning
- Department of Biological Sciences, Minnesota State University Mankato, 242 Trafton Science Center South, Mankato, MN 56001, USA
| | - Mark A Hancock
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
| | - Claus Schmitz
- Department of Structural Biology, Molecular Biology Institute of Barcelona, Spanish Research Council, Barcelona Science Park, Barcelona E-08028, Spain
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków PL-30-387, Poland
| | - Jan Potempa
- Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, Kraków PL-30-387, Poland
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, 501 S Preston St, Louisville, KY 40202, USA
| | - Maria Sola
- Department of Structural Biology, Molecular Biology Institute of Barcelona, Spanish Research Council, Barcelona Science Park, Barcelona E-08028, Spain
| | - Jean-François Trempe
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
- Department of Pharmacology & Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, QC H3G 1Y6, Canada
| | - Yongtao Zhu
- Department of Biological Sciences, Minnesota State University Mankato, 242 Trafton Science Center South, Mankato, MN 56001, USA
- Department of Biological Sciences, Xi’an Jiaotong-Liverpool University, 111 Ren’ai Road, Suzhou Dushu Lake Science and Education Innovation District, Suzhou Industrial Park, Suzhou, Jiangsu 215123, China
| | - Mary Ellen Davey
- Department of Microbiology, The Forsyth Institute, 245 First St, Cambridge, MA 02142, USA
| | - Natalie Zeytuni
- Department of Anatomy and Cell Biology, McGill University, 3640 Rue University, Montreal, QC H3A 0C7, Canada
- Centre de Recherche en Biologie Structurale (CRBS), McGill University, 3649 Promenade Sir William Olser, Montreal, QC H3G 0B1, Canada
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Saran A, Kim HM, Manning I, Hancock MA, Schmitz C, Madej M, Potempa J, Sola M, Trempe JF, Zhu Y, Davey ME, Zeytuni N. Unveiling the Molecular Mechanisms of the Type-IX Secretion System's Response Regulator: Structural and Functional Insights. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.15.594396. [PMID: 38798656 PMCID: PMC11118453 DOI: 10.1101/2024.05.15.594396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
The Type-IX secretion system (T9SS) is a nanomachinery utilized by bacterial pathogens to facilitate infection. The system is regulated by a signaling cascade serving as its activation switch. A pivotal member in this cascade, the response regulator protein PorX, represents a promising drug target to prevent the secretion of virulence factors. Here, we provide a comprehensive characterization of PorX both in vitro and in vivo . First, our structural studies revealed PorX harbours a unique enzymatic effector domain, which, surprisingly, shares structural similarities with the alkaline phosphatase superfamily, involved in nucleotide and lipid signaling pathways. Importantly, such pathways have not been associated with the T9SS until now. Enzymatic characterization of PorX's effector domain revealed a zinc-dependent phosphodiesterase activity, with active site dimensions suitable to accommodate a large substrate. Unlike typical response regulators that dimerize via their receiver domain upon phosphorylation, we found that zinc can also induce conformational changes and promote PorX's dimerization via an unexpected interface. These findings suggest that PorX can serve as a cellular zinc sensor, broadening our understanding of its regulatory mechanisms. Despite the strict conservation of PorX in T9SS-utilizing bacteria, we demonstrate that PorX is essential for virulence factors secretion in Porphyromonas gingivalis and affects metabolic enzymes secretion in the non-pathogenic Flavobacterium johnsoniae , but not for the secretion of gliding adhesins. Overall, this study advances our structural and functional understanding of PorX, highlighting its potential as a druggable target for intervention strategies aimed at disrupting the T9SS and mitigating virulence in pathogenic species.
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Mahmud ASM, Seers CA, Huq NL, Zhang L, Butler CA, Moore C, Cross KJ, Reynolds EC. Production and properties of adhesin-free gingipain proteinase RgpA. Sci Rep 2023; 13:10780. [PMID: 37402780 DOI: 10.1038/s41598-023-37534-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 06/23/2023] [Indexed: 07/06/2023] Open
Abstract
The Arg-specific gingipains of Porphyromonas gingivalis RgpA and RgpB have 97% identical sequences in their catalytic domains yet their propeptides are only 76% identical. RgpA isolates as a proteinase-adhesin complex (HRgpA) which hinders direct kinetic comparison of RgpAcat as a monomer with monomeric RgpB. We tested modifications of rgpA identifying a variant that enabled us to isolate histidine-tagged monomeric RgpA (rRgpAH). Kinetic comparisons between rRgpAH and RgpB used benzoyl-L-Arg-4-nitroanilide with and without cysteine and glycylglycine acceptor molecules. With no glycylglycine, values of Km, Vmax, kcat and kcat/Km for each enzyme were similar, but with glycylglycine Km decreased, Vmax increased and kcat increased ~ twofold for RgpB but ~ sixfold for rRgpAH. The kcat/Km for rRgpAH was unchanged whereas that of RgpB more than halved. Recombinant RgpA propeptide inhibited rRgpAH and RgpB with Ki 13 nM and 15 nM Ki respectively slightly more effectively than RgpB propeptide which inhibited rRgpAH and RgpB with Ki 22 nM and 29 nM respectively (p < 0.0001); a result that may be attributable to the divergent propeptide sequences. Overall, the data for rRgpAH reflected observations previously made by others using HRgpA, indicating rRgpAH fidelity and confirming the first production and isolation of functional affinity tagged RgpA.
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Affiliation(s)
- Abu Sayeed M Mahmud
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Christine A Seers
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - N Laila Huq
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Lianyi Zhang
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Catherine A Butler
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Caroline Moore
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Keith J Cross
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Parkville, VIC, 3010, Australia.
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Yang D, Jiang C, Ning B, Kong W, Shi Y. The PorX/PorY system is a virulence factor of Porphyromonas gingivalis and mediates the activation of the type IX secretion system. J Biol Chem 2021; 296:100574. [PMID: 33757767 PMCID: PMC8050853 DOI: 10.1016/j.jbc.2021.100574] [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: 01/09/2021] [Revised: 03/13/2021] [Accepted: 03/19/2021] [Indexed: 12/13/2022] Open
Abstract
PorX/PorY is a two-component system (TCS) of Porphyromonas gingivalis that governs transcription of numerous genes including those encoding a type IX secretion system (T9SS) for gingipain secretion and heme accumulation. Here, an in vitro analysis showed that the response regulator PorX specifically bound to two regions in the promoter of porT, a known PorX-regulated T9SS gene, thus demonstrating that PorX/PorY can directly regulate specific target genes. A truncated PorX protein containing the N-terminal receiver and effector domains retained a wild-type ability in both transcription regulation and heme accumulation, ruling out the role of the C-terminal ALP domain in gene regulation. The PorX/PorY system was the only TCS essential for heme accumulation and concomitantly responded to hemin to stimulate transcription of several known PorX-dependent genes in a concentration-dependent manner. We found that PorX/PorY activated the sigH gene, which encodes a sigma factor known for P. gingivalis adaptation to hydrogen peroxide (H2O2). Consistently, both ΔporX and ΔsigH mutants were susceptible to H2O2, suggesting a PorX/PorY-σH regulatory cascade to confer resistance to oxidative stress. Furthermore, the ΔporX mutant became susceptible to high hemin levels that could induce oxidative stress. Therefore, a possible reason why hemin activates PorX/PorY is to confer resistance to hemin-induced oxidative stress. We also demonstrated that PorX/PorY was essential for P. gingivalis virulence because the ΔporX mutant was avirulent in a mouse model. Specifically, this TCS was required for the repression of proinflammatory cytokines secreted by dendritic cells and T cells in the P. gingivalis–infected mice.
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Affiliation(s)
- Dezhi Yang
- The School of Life Sciences, Arizona State University, Tempe, Arizona, USA; Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, Arizona, USA
| | - Chizhou Jiang
- The School of Life Sciences, Arizona State University, Tempe, Arizona, USA; Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, Arizona, USA
| | - Bo Ning
- The Center for Cellular and Molecular Diagnostics, Tulane University School of Medicine, New Orleans, Louisiana, USA
| | - Wei Kong
- Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, Arizona, USA.
| | - Yixin Shi
- The School of Life Sciences, Arizona State University, Tempe, Arizona, USA; Biodesign Center for Immunotherapy, Vaccines and Virotherapy, Arizona State University, Tempe, Arizona, USA.
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Seers CA, Mahmud ASM, Huq NL, Cross KJ, Reynolds EC. Porphyromonas gingivalis laboratory strains and clinical isolates exhibit different distribution of cell surface and secreted gingipains. J Oral Microbiol 2020; 13:1858001. [PMID: 33391630 PMCID: PMC7733959 DOI: 10.1080/20002297.2020.1858001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: The cell-surface cysteine proteinases RgpA, RgpB (Arg-gingipain), and Kgp (Lys-gingipain) are major virulence factors of P. gingivalis, a keystone pathogen in the development of destructive periodontal disease. The gingipains function as proteinases and transpeptidases utilising small peptides such as glycylglycine as acceptor molecules. However, the characteristics of the gingipains from most P. gingivalis strains have not been determined. Methods: We determined the phenotypes of a panel of P. gingivalis laboratory strains and global clinical isolates with respect to growth on blood agar plus whole-cell and vesicle-free culture supernatant (VFSN) Arg- and Lys-specific proteinase activities. Results: The P. gingivalis isolates exhibited different growth characteristics and hydrolysis of haemoglobin in solid media. Whole-cell Arg-gingipain Vmax varied 5.8-fold and the whole cell Lys-gingipain Vmax varied 2.1-fold across the strains. Furthermore, the P. gingivalis strains showed more than 107-fold variance in soluble Arg-gingipain activity in VFSN and more than 371-fold variance in soluble Lys-gingipain activity in VFSN. Glycylglycine and cysteine stimulated Arg- and Lys-specific cleavage activities of all strains. The stimulation by cysteine was in addition to its redox effect consistent with both glycylglycine and cysteine promoting transpeptidation.
Conclusion: The global P. gingivalis clinical isolates exhibit different Arg- and Lys‑gingipain activities with substantial variability in the level of soluble proteinases released into the environment.
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Affiliation(s)
- Christine A Seers
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - A Sayeed M Mahmud
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - N Laila Huq
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Keith J Cross
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
| | - Eric C Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute, The University of Melbourne, Melbourne, Australia
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PorA, a conserved C-terminal domain-containing protein, impacts the PorXY-SigP signaling of the type IX secretion system. Sci Rep 2020; 10:21109. [PMID: 33273542 PMCID: PMC7712824 DOI: 10.1038/s41598-020-77987-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 11/19/2020] [Indexed: 01/07/2023] Open
Abstract
Porphyromonas gingivalis, a periodontal pathogen, translocates many virulence factors including the cysteine proteases referred to as gingipains to the cell surface via the type IX secretion system (T9SS). Expression of the T9SS component proteins is regulated by the tandem signaling of the PorXY two-component system and the ECF sigma factor SigP. However, the details of this regulatory pathway are still unknown. We found that one of the T9SS conserved C-terminal domain-containing proteins, PGN_0123, which we have designated PorA, is involved in regulating expression of genes encoding T9SS structural proteins and that PorA can be translocated onto the cell surface without the T9SS translocation machinery. X-ray crystallography revealed that PorA has a domain similar to the mannose-binding domain of Escherichia coli FimH, the tip protein of Type 1 pilus. Mutations in the cytoplasmic domain of the sensor kinase PorY conferred phenotypic recovery on the ΔporA mutant. The SigP sigma factor, which is activated by the PorXY two-component system, markedly decreased in the ΔporA mutant. These results strongly support a potential role for PorA in relaying a signal from the cell surface to the PorXY-SigP signaling pathway.
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Nakanishi H, Nonaka S, Wu Z. Microglial Cathepsin B and Porphyromonas gingivalis Gingipains as Potential Therapeutic Targets for Sporadic Alzheimer’s Disease. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2020; 19:495-502. [DOI: 10.2174/1871527319666200708125130] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/17/2020] [Accepted: 04/20/2020] [Indexed: 01/19/2023]
Abstract
Many efforts have been made to develop therapeutic agents for Alzheimer’s Disease (AD)
based on the amyloid cascade hypothesis, but there is no effective therapeutic agent at present. Now,
much attention has been paid to infiltrate pathogens in the brain as a trigger of AD. These pathogens,
or their virulence factors, may directly cross a weakened blood-brain barrier, reach the brain and cause
neurological damage by eliciting neuroinflammation. Moreover, there is growing clinical evidence of
a correlation between periodontitis and cognitive decline in AD patients. Recent studies have revealed
that microglial cathepsin B is increasingly induced by lipopolysaccharide of Porphylomonas gingivalis,
a major pathogen of periodontal disease. Moreover, gingipains produced by P. gingivalis play
critical roles in neuroinflammation mediated by microglia and cognitive decline in mice. Furthermore,
an orally bioavailable and brain-permeable inhibitor of gingipain is now being tested in AD patients. It
is largely expected that clinical studies countering bacterial virulence factors may pave the way to establish
the prevention and early treatment of AD.
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Affiliation(s)
- Hiroshi Nakanishi
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Saori Nonaka
- Department of Pharmacology, Faculty of Pharmacy, Yasuda Women’s University, Hiroshima 731-0153, Japan
| | - Zhou Wu
- OBT Research Center, Faculty of Dental Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Miller DP, Scott DA. Inherently and Conditionally Essential Protein Catabolism Genes of Porphyromonas gingivalis. Trends Microbiol 2020; 29:54-64. [PMID: 33071035 DOI: 10.1016/j.tim.2020.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/01/2020] [Accepted: 09/02/2020] [Indexed: 02/06/2023]
Abstract
Proteases are critical virulence determinants of Porphyromonas gingivalis, an emerging Alzheimer's disease, cancer, and arthritis pathogen and established agent of periodontitis. Transposon sequencing has been employed to define the core essential genome of this bacterium and genes conditionally essential in multiple environments - abscess formation; epithelial colonization; and cigarette smoke toxin exposure; as well as to elucidate genes required for iron acquisition and a functional type 9 secretion system. Validated and predicted protein catabolism genes identified include a combination of established virulence factors and a larger set of seemingly more mundane proteolytic genes. The functions and relevance of genes that share essentiality in multiple disease-relevant conditions are examined. These common stress-related genes may represent particularly attractive therapeutic targets for the control of P. gingivalis infections.
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Affiliation(s)
- Daniel P Miller
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, VA, USA
| | - David A Scott
- Department of Oral Immunology and Infectious Diseases, University of Louisville, Louisville, KY, USA.
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Gingimaps: Protein Localization in the Oral Pathogen Porphyromonas gingivalis. Microbiol Mol Biol Rev 2020; 84:84/1/e00032-19. [PMID: 31896547 DOI: 10.1128/mmbr.00032-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Porphyromonas gingivalis is an oral pathogen involved in the widespread disease periodontitis. In recent years, however, this bacterium has been implicated in the etiology of another common disorder, the autoimmune disease rheumatoid arthritis. Periodontitis and rheumatoid arthritis were known to correlate for decades, but only recently a possible molecular connection underlying this association has been unveiled. P. gingivalis possesses an enzyme that citrullinates certain host proteins and, potentially, elicits autoimmune antibodies against such citrullinated proteins. These autoantibodies are highly specific for rheumatoid arthritis and have been purported both as a symptom and a potential cause of the disease. The citrullinating enzyme and other major virulence factors of P. gingivalis, including some that were implicated in the etiology of rheumatoid arthritis, are targeted to the host tissue as secreted or outer-membrane-bound proteins. These targeting events play pivotal roles in the interactions between the pathogen and its human host. Accordingly, the overall protein sorting and secretion events in P. gingivalis are of prime relevance for understanding its full disease-causing potential and for developing preventive and therapeutic approaches. The aim of this review is therefore to offer a comprehensive overview of the subcellular and extracellular localization of all proteins in three reference strains and four clinical isolates of P. gingivalis, as well as the mechanisms employed to reach these destinations.
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Sato K, Kakuda S, Yukitake H, Kondo Y, Shoji M, Takebe K, Narita Y, Naito M, Nakane D, Abiko Y, Hiratsuka K, Suzuki M, Nakayama K. Immunoglobulin‐like domains of the cargo proteins are essential for protein stability during secretion by the type IX secretion system. Mol Microbiol 2018; 110:64-81. [DOI: 10.1111/mmi.14083] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2018] [Indexed: 01/12/2023]
Affiliation(s)
- Keiko Sato
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Shinji Kakuda
- Institute for Protein Research Osaka University Yamadaoka, Suita Osaka 565‐0871Japan
| | - Hideharu Yukitake
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Yoshio Kondo
- Department of Pediatric Dentistry Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Mikio Shoji
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Katsuki Takebe
- Institute for Protein Research Osaka University Yamadaoka, Suita Osaka 565‐0871Japan
| | - Yuka Narita
- Department of Functional Bioscience, Infection Biology Fukuoka Dental College Matsudo, Tamura, Sawara, Fukuoka 814‐0913Japan
| | - Mariko Naito
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
| | - Daisuke Nakane
- Department of Physics, Faculty of Science Gakushuin University Toshima‐ku, Tokyo 171‐8588Japan
| | - Yoshimitsu Abiko
- Department of Biochemistry and Molecular Biology Nihon University School of Dentistry at Matsudo Matsudo Chiba 271‐8587Japan
| | - Koichi Hiratsuka
- Department of Biochemistry and Molecular Biology Nihon University School of Dentistry at Matsudo Matsudo Chiba 271‐8587Japan
| | - Mamoru Suzuki
- Institute for Protein Research Osaka University Yamadaoka, Suita Osaka 565‐0871Japan
| | - Koji Nakayama
- Department of Microbiology and Oral Infection Nagasaki University Graduate School of Biomedical Sciences Nagasaki Nagasaki 852‐8588Japan
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11
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Shoji M, Sato K, Yukitake H, Kamaguchi A, Sasaki Y, Naito M, Nakayama K. Identification of genes encoding glycosyltransferases involved in lipopolysaccharide synthesis inPorphyromonas gingivalis. Mol Oral Microbiol 2017; 33:68-80. [DOI: 10.1111/omi.12200] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 12/16/2022]
Affiliation(s)
- M. Shoji
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - K. Sato
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - H. Yukitake
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - A. Kamaguchi
- Department of Oral Microbiology; School of Dentistry; Health Sciences University of Hokkaido; Hokkaido Japan
| | - Y. Sasaki
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - M. Naito
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
| | - K. Nakayama
- Department of Microbiology and Oral Infection; Nagasaki University Graduate School of Biomedical Sciences; Nagasaki Japan
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12
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Jinmei Z, Lei Z, Yafei W. [Research progress on the type Ⅸ secretion system of Porphyromonas gingivalis]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2017; 35:538-542. [PMID: 29188653 DOI: 10.7518/hxkq.2017.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In recent years, the study found that Porphyromonas gingivalis type Ⅸ secretion system (T9SS) is a novel protein secretion system, also known as Por secretion system (PorSS). Unlike the eight protein secretion systems found in the past, the system is a polyprotein complex found only in Bacteroides. The secreted proteins have both N- and C-terminus, where the former includes Sec-dependent type Ⅰ signals peptide, and the latter contains conserved domains (C-terminal conserved domain, CTD). Porphyromonas gingivalis T9SS includes proteins such as intima, outer membrane, cytoplasm, and cell cycle, including at least 34 proteins containing CTD. Porphyromonas gingivalis T9SS is involved in regulating associated virulence factors including gingivin, fimbriae, lipopolysaccharide, HBP35, CPG70 protein and peptidyl-arginine deiminase. These CTD-containing virulence proteins are localized by T9SS and then released to the extracellular domain, thereby destroying periodontal tissue. Therefore, this review summarizes the research progress on the T9SS of Porphyromonas gingivalis.
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Affiliation(s)
- Zhang Jinmei
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zhao Lei
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Wu Yafei
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, Dept. of Periodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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13
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Veith PD, Glew MD, Gorasia DG, Reynolds EC. Type IX secretion: the generation of bacterial cell surface coatings involved in virulence, gliding motility and the degradation of complex biopolymers. Mol Microbiol 2017; 106:35-53. [DOI: 10.1111/mmi.13752] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/14/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Paul D. Veith
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
| | - Michelle D. Glew
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
| | - Dhana G. Gorasia
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
| | - Eric C. Reynolds
- Oral Health Cooperative Research Centre, Melbourne Dental School, Bio21 Institute; The University of Melbourne; Melbourne Australia
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14
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Goulas T, Ksiazek M, Garcia-Ferrer I, Sochaj-Gregorczyk AM, Waligorska I, Wasylewski M, Potempa J, Gomis-Rüth FX. A structure-derived snap-trap mechanism of a multispecific serpin from the dysbiotic human oral microbiome. J Biol Chem 2017; 292:10883-10898. [PMID: 28512127 PMCID: PMC5491774 DOI: 10.1074/jbc.m117.786533] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/04/2017] [Indexed: 10/19/2022] Open
Abstract
Enduring host-microbiome relationships are based on adaptive strategies within a particular ecological niche. Tannerella forsythia is a dysbiotic member of the human oral microbiome that inhabits periodontal pockets and contributes to chronic periodontitis. To counteract endopeptidases from the host or microbial competitors, T. forsythia possesses a serpin-type proteinase inhibitor called miropin. Although serpins from animals, plants, and viruses have been widely studied, those from prokaryotes have received only limited attention. Here we show that miropin uses the serpin-type suicidal mechanism. We found that, similar to a snap trap, the protein transits from a metastable native form to a relaxed triggered or induced form after cleavage of a reactive-site target bond in an exposed reactive-center loop. The prey peptidase becomes covalently attached to the inhibitor, is dragged 75 Å apart, and is irreversibly inhibited. This coincides with a large conformational rearrangement of miropin, which inserts the segment upstream of the cleavage site as an extra β-strand in a central β-sheet. Standard serpins possess a single target bond and inhibit selected endopeptidases of particular specificity and class. In contrast, miropin uniquely blocked many serine and cysteine endopeptidases of disparate architecture and substrate specificity owing to several potential target bonds within the reactive-center loop and to plasticity in accommodating extra β-strands of variable length. Phylogenetic studies revealed a patchy distribution of bacterial serpins incompatible with a vertical descent model. This finding suggests that miropin was acquired from the host through horizontal gene transfer, perhaps facilitated by the long and intimate association of T. forsythia with the human gingiva.
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Affiliation(s)
- Theodoros Goulas
- From the Proteolysis Lab, Structural Biology Unit, María de Maeztu Unit of Excellence, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, 08028 Barcelona, Spain
| | - Miroslaw Ksiazek
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology and
- the Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, Kentucky 40202
| | - Irene Garcia-Ferrer
- From the Proteolysis Lab, Structural Biology Unit, María de Maeztu Unit of Excellence, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, 08028 Barcelona, Spain
| | - Alicja M Sochaj-Gregorczyk
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology and
- the Malopolska Centre of Biotechnology, Jagiellonian University, 30-387 Kraków, Poland, and
| | - Irena Waligorska
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology and
| | - Marcin Wasylewski
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology and
| | - Jan Potempa
- the Department of Microbiology, Faculty of Biochemistry, Biophysics and Biotechnology and
- the Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, Kentucky 40202
| | - F Xavier Gomis-Rüth
- From the Proteolysis Lab, Structural Biology Unit, María de Maeztu Unit of Excellence, Molecular Biology Institute of Barcelona, Consejo Superior de Investigaciones Científicas, 08028 Barcelona, Spain,
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15
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Lasica AM, Ksiazek M, Madej M, Potempa J. The Type IX Secretion System (T9SS): Highlights and Recent Insights into Its Structure and Function. Front Cell Infect Microbiol 2017. [PMID: 28603700 DOI: 10.3389/fcimb.2017.00215.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Protein secretion systems are vital for prokaryotic life, as they enable bacteria to acquire nutrients, communicate with other species, defend against biological and chemical agents, and facilitate disease through the delivery of virulence factors. In this review, we will focus on the recently discovered type IX secretion system (T9SS), a complex translocon found only in some species of the Bacteroidetes phylum. T9SS plays two roles, depending on the lifestyle of the bacteria. It provides either a means of movement (called gliding motility) for peace-loving environmental bacteria or a weapon for pathogens. The best-studied members of these two groups are Flavobacterium johnsoniae, a commensal microorganism often found in water and soil, and Porphyromonas gingivalis, a human oral pathogen that is a major causative agent of periodontitis. In P. gingivalis and some other periodontopathogens, T9SS translocates proteins, especially virulence factors, across the outer membrane (OM). Proteins destined for secretion bear a conserved C-terminal domain (CTD) that directs the cargo to the OM translocon. At least 18 proteins are involved in this still enigmatic process, with some engaged in the post-translational modification of T9SS cargo proteins. Upon translocation across the OM, the CTD is removed by a protease with sortase-like activity and an anionic LPS is attached to the newly formed C-terminus. As a result, a cargo protein could be secreted into the extracellular milieu or covalently attached to the bacterial surface. T9SS is regulated by a two-component system; however, the precise environmental signal that triggers it has not been identified. Exploring unknown systems contributing to bacterial virulence is exciting, as it may eventually lead to new therapeutic strategies. During the past decade, the major components of T9SS were identified, as well as hints suggesting the possible mechanism of action. In addition, the list of characterized cargo proteins is constantly growing. The actual structure of the translocon, situated in the OM of bacteria, remains the least explored area; however, new technical approaches and increasing scientific attention have resulted in a growing body of data. Therefore, we present a compact up-to-date review of this topic.
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Affiliation(s)
- Anna M Lasica
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Bacterial Genetics, Faculty of Biology, Institute of Microbiology, University of WarsawWarsaw, Poland
| | - Miroslaw Ksiazek
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Jan Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
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16
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Lasica AM, Ksiazek M, Madej M, Potempa J. The Type IX Secretion System (T9SS): Highlights and Recent Insights into Its Structure and Function. Front Cell Infect Microbiol 2017; 7:215. [PMID: 28603700 PMCID: PMC5445135 DOI: 10.3389/fcimb.2017.00215] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/11/2017] [Indexed: 12/11/2022] Open
Abstract
Protein secretion systems are vital for prokaryotic life, as they enable bacteria to acquire nutrients, communicate with other species, defend against biological and chemical agents, and facilitate disease through the delivery of virulence factors. In this review, we will focus on the recently discovered type IX secretion system (T9SS), a complex translocon found only in some species of the Bacteroidetes phylum. T9SS plays two roles, depending on the lifestyle of the bacteria. It provides either a means of movement (called gliding motility) for peace-loving environmental bacteria or a weapon for pathogens. The best-studied members of these two groups are Flavobacterium johnsoniae, a commensal microorganism often found in water and soil, and Porphyromonas gingivalis, a human oral pathogen that is a major causative agent of periodontitis. In P. gingivalis and some other periodontopathogens, T9SS translocates proteins, especially virulence factors, across the outer membrane (OM). Proteins destined for secretion bear a conserved C-terminal domain (CTD) that directs the cargo to the OM translocon. At least 18 proteins are involved in this still enigmatic process, with some engaged in the post-translational modification of T9SS cargo proteins. Upon translocation across the OM, the CTD is removed by a protease with sortase-like activity and an anionic LPS is attached to the newly formed C-terminus. As a result, a cargo protein could be secreted into the extracellular milieu or covalently attached to the bacterial surface. T9SS is regulated by a two-component system; however, the precise environmental signal that triggers it has not been identified. Exploring unknown systems contributing to bacterial virulence is exciting, as it may eventually lead to new therapeutic strategies. During the past decade, the major components of T9SS were identified, as well as hints suggesting the possible mechanism of action. In addition, the list of characterized cargo proteins is constantly growing. The actual structure of the translocon, situated in the OM of bacteria, remains the least explored area; however, new technical approaches and increasing scientific attention have resulted in a growing body of data. Therefore, we present a compact up-to-date review of this topic.
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Affiliation(s)
- Anna M Lasica
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Bacterial Genetics, Faculty of Biology, Institute of Microbiology, University of WarsawWarsaw, Poland
| | - Miroslaw Ksiazek
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Mariusz Madej
- Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
| | - Jan Potempa
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of DentistryLouisville, KY, United States.,Department of Microbiology, Faculty of Biochemistry, Biophysics, and Biotechnology, Jagiellonian UniversityKrakow, Poland
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17
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Nakayama K. [The type IX secretion system and the type V pilus in the phylum Bacteroidetes]. Nihon Saikingaku Zasshi 2017; 72:219-227. [PMID: 29109335 DOI: 10.3412/jsb.72.219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Many bacteria symbiotic and parasitic in humans are included in the genera Bacteroides, Prevotella, Porphyromonas and others, which belong to the phylum Bacteroidetes. We have been studying gingipain, a major secretory protease of Porphyromonas gingivalis which is a periodontopathogenic bacterium belonging to the genus Porphyromonas, and pili which contribute to host colonization in the bacterium. In the process, it was found that gingipain was secreted by a system not reported previously. Furthermore, this secretion system was found to exist widely in the Bacteroidetes phylum bacteria and closely related to the gliding motility of bacteroidete bacteria, and it was named the Por secretion system (later renamed the type IX secretion system). Regarding P. gingivalis pili, it was found that the pilus protein is transported as a lipoprotein to the cell surface, and the pilus formation occurs due to degradation by arginine-gingipain. Pili with this novel formation mechanism was found to be widely present in bacteria belonging to the class Bacteroidia in the phylum Bacteroidetes and was named the type V pili.
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Affiliation(s)
- Koji Nakayama
- Department of Microbiology and Oral Infection, Nagasaki University Graduate School of Biomedical Sciences
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18
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Shoji M, Nakayama K. Glycobiology of the oral pathogen Porphyromonas gingivalis and related species. Microb Pathog 2015; 94:35-41. [PMID: 26456570 DOI: 10.1016/j.micpath.2015.09.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 09/29/2015] [Accepted: 09/30/2015] [Indexed: 10/22/2022]
Abstract
Until recently, glycoproteins had only been described in eukaryotes. However, advances in detection methods and genome analyses have allowed the discovery of N-linked or O-linked glycoproteins, similar to those found in eukaryotes, in some bacterial species. These prokaryotic glycoproteins play roles in adhesion, solubility, formation of protein complexes, protection from protein degradation, and changes in antigenicity. Periodontal pathogen Porphyromonas gingivalis secretes virulence proteins via the type IX secretion system, some of which localize on the cell surface by binding to lipopolysaccharide (LPS). These virulence proteins have a conserved C-terminal domain (CTD) region, which is used as a secretion signal. However, it is still uncertain how the secreted proteins on the cell surface bind to LPS. In this review, we discuss the synthesis of P. gingivalis O polysaccharide, which plays a role in anchoring the CTD protein on the cell surface, and recent discoveries of glycoproteins in P. gingivalis as well as other species in the phylum Bacteroidetes.
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Affiliation(s)
- Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, 852-8588, Japan.
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19
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Nakayama K. Porphyromonas gingivalis and related bacteria: from colonial pigmentation to the type IX secretion system and gliding motility. J Periodontal Res 2014; 50:1-8. [PMID: 25546073 PMCID: PMC4674972 DOI: 10.1111/jre.12255] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2014] [Indexed: 12/22/2022]
Abstract
Porphyromonas gingivalis is a gram-negative, non-motile, anaerobic bacterium implicated as a major pathogen in periodontal disease. P. gingivalis grows as black-pigmented colonies on blood agar, and many bacteriologists have shown interest in this property. Studies of colonial pigmentation have revealed a number of important findings, including an association with the highly active extracellular and surface proteinases called gingipains that are found in P. gingivalis. The Por secretion system, a novel type IX secretion system (T9SS), has been implicated in gingipain secretion in studies using non-pigmented mutants. In addition, many potent virulence proteins, including the metallocarboxypeptidase CPG70, 35 kDa hemin-binding protein HBP35, peptidylarginine deiminase PAD and Lys-specific serine endopeptidase PepK, are secreted through the T9SS. These findings have not been limited to P. gingivalis but have been extended to other bacteria belonging to the phylum Bacteroidetes. Many Bacteroidetes species possess the T9SS, which is associated with gliding motility for some of these bacteria.
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Affiliation(s)
- K Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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20
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Narita Y, Sato K, Yukitake H, Shoji M, Nakane D, Nagano K, Yoshimura F, Naito M, Nakayama K. Lack of a surface layer in Tannerella forsythia mutants deficient in the type IX secretion system. MICROBIOLOGY-SGM 2014; 160:2295-2303. [PMID: 25023245 PMCID: PMC4175972 DOI: 10.1099/mic.0.080192-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Tannerella forsythia, a Gram-negative anaerobic bacterium, is an important pathogen in periodontal disease. This bacterium possesses genes encoding all known components of the type IX secretion system (T9SS). T. forsythia mutants deficient in genes orthologous to the T9SS-encoding genes porK, porT and sov were constructed. All porK, porT and sov single mutants lacked the surface layer (S-layer) and expressed less-glycosylated versions of the S-layer glycoproteins TfsA and TfsB. In addition, these mutants exhibited decreased haemagglutination and increased biofilm formation. Comparison of the proteins secreted by the porK and WT strains revealed that the secretion of several proteins containing C-terminal domain (CTD)-like sequences is dependent on the porK gene. These results indicate that the T9SS is functional in T. forsythia and contributes to the translocation of CTD proteins to the cell surface or into the extracellular milieu.
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Affiliation(s)
- Yuka Narita
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
| | - Keiko Sato
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
| | - Hideharu Yukitake
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
| | - Mikio Shoji
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
| | - Daisuke Nakane
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
| | - Keiji Nagano
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Mariko Naito
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
| | - Koji Nakayama
- Division of Microbiology and Oral Infection, Department of Molecular Microbiology and Immunology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 819-8588, Japan
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