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Wunder EA, Figueira CP, Benaroudj N, Hu B, Tong BA, Trajtenberg F, Liu J, Reis MG, Charon NW, Buschiazzo A, Picardeau M, Ko AI. A novel flagellar sheath protein, FcpA, determines filament coiling, translational motility and virulence for the Leptospira spirochete. Mol Microbiol 2016; 101:457-70. [PMID: 27113476 DOI: 10.1111/mmi.13403] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2016] [Indexed: 12/28/2022]
Abstract
Leptospira are unique among bacteria based on their helical cell morphology with hook-shaped ends and the presence of periplasmic flagella (PF) with pronounced spontaneous supercoiling. The factors that provoke such supercoiling, as well as the role that PF coiling plays in generating the characteristic hook-end cell morphology and motility, have not been elucidated. We have now identified an abundant protein from the pathogen L. interrogans, exposed on the PF surface, and named it Flagellar-coiling protein A (FcpA). The gene encoding FcpA is highly conserved among Leptospira and was not found in other bacteria. fcpA(-) mutants, obtained from clinical isolates or by allelic exchange, had relatively straight, smaller-diameter PF, and were not able to produce translational motility. These mutants lost their ability to cause disease in the standard hamster model of leptospirosis. Complementation of fcpA restored the wild-type morphology, motility and virulence phenotypes. In summary, we identified a novel Leptospira 36-kDa protein, the main component of the spirochete's PF sheath, and a key determinant of the flagella's coiled structure. FcpA is essential for bacterial translational motility and to enable the spirochete to penetrate the host, traverse tissue barriers, disseminate to cause systemic infection and reach target organs.
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Affiliation(s)
- Elsio A Wunder
- Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, CT, 06520, USA.,Gonçalo Moniz Research Center, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Bahia, 40296-710, Brazil
| | - Cláudio P Figueira
- Gonçalo Moniz Research Center, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Bahia, 40296-710, Brazil
| | - Nadia Benaroudj
- Institut Pasteur, Unit of Biology of Spirochetes, 75724 Paris cedex 15, France
| | - Bo Hu
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, TX, 77030, USA
| | - Brian A Tong
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, TX, 77030, USA
| | - Felipe Trajtenberg
- Laboratory of Molecular & Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, 11400, Uruguay
| | - Jun Liu
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston, Houston, TX, 77030, USA
| | - Mitermayer G Reis
- Gonçalo Moniz Research Center, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Bahia, 40296-710, Brazil
| | - Nyles W Charon
- Department of Microbiology and Immunology, West Virginia University, Morgantown, WV, 26506, USA
| | - Alejandro Buschiazzo
- Laboratory of Molecular & Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, 11400, Uruguay.,Department of Structural Biology and Chemistry, Institute Pasteur, 75724 Paris cedex15, France
| | - Mathieu Picardeau
- Institut Pasteur, Unit of Biology of Spirochetes, 75724 Paris cedex 15, France
| | - Albert I Ko
- Department of Epidemiology of Microbial Disease, Yale School of Public Health, New Haven, CT, 06520, USA.,Gonçalo Moniz Research Center, Oswaldo Cruz Foundation, Brazilian Ministry of Health, Salvador, Bahia, 40296-710, Brazil
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2
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Surface immunolabeling and consensus computational framework to identify candidate rare outer membrane proteins of Treponema pallidum. Infect Immun 2010; 78:5178-94. [PMID: 20876295 DOI: 10.1128/iai.00834-10] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Treponema pallidum reacts poorly with the antibodies present in rabbit and human syphilitic sera, a property attributed to the paucity of proteins in its outer membrane. To better understand the basis for the syphilis spirochete's "stealth pathogenicity," we used a dual-label, 3-step amplified assay in which treponemes encapsulated in gel microdroplets were probed with syphilitic sera in parallel with anti-FlaA antibodies. A small (approximately 5 to 10%) but reproducible fraction of intact treponemes bound IgG and/or IgM antibodies. Three lines of evidence supported the notion that the surface antigens were likely β-barrel-forming outer membrane proteins (OMPs): (i) surface labeling with anti-lipoidal (VDRL) antibodies was not observed, (ii) immunoblot analysis confirmed prior results showing that T. pallidum glycolipids are not immunoreactive, and (iii) labeling of intact organisms was not appreciably affected by proteinase K (PK) treatment. With this method, we also demonstrate that TprK (TP0897), an extensively studied candidate OMP, and TP0136, a lipoprotein recently reported to be surface exposed, are both periplasmic. Consistent with the immunolabeling studies, TprK was also found to lack amphiphilicity, a characteristic property of β-barrel-forming proteins. Using a consensus computational framework that combined subcellular localization and β-barrel structural prediction tools, we generated ranked groups of candidate rare OMPs, the predicted T. pallidum outer membrane proteome (OMPeome), which we postulate includes the surface-exposed molecules detected by our enhanced gel microdroplet assay. In addition to underscoring the syphilis spirochete's remarkably poor surface antigenicity, our findings help to explain the complex and shifting balance between pathogen and host defenses that characterizes syphilitic infection.
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3
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Abstract
The expression of flagellin genes in most bacteria is typically regulated by the flagellum-specific sigma(28) factor FliA, and an anti-sigma(28) factor, FlgM. However, the regulatory hierarchy in several bacteria that have multiple flagellins is more complex. In these bacteria, the flagellin genes are often transcribed by at least two different sigma factors. The flagellar filament in spirochetes consists of one to three FlaB core proteins and at least one FlaA sheath protein. Here, the genetically amenable bacterium Brachyspira hyodysenteriae was used as a model spirochete to investigate the regulation of its four flagellin genes, flaA, flaB1, flaB2, and flaB3. We found that the flaB1 and flaB2 genes are regulated by sigma(28), whereas the flaA and flaB3 genes are controlled by sigma(70). The analysis of a flagellar motor switch fliG mutant further supported this proposition; in the mutant, the transcription of flaB1 and flaB2 was inhibited, but that of flaA and flaB3 was not. In addition, the continued expression of flaA and flaB3 in the mutant resulted in the formation of incomplete flagellar filaments that were hollow tubes and consisted primarily of FlaA. Finally, our recent studies have shown that each flagellin unit contributes to the stiffness of the periplasmic flagella, and this stiffness directly correlates with motility. The regulatory mechanism identified here should allow spirochetes to change the relative ratio of these flagellin proteins and, concomitantly, vary the stiffness of their flagellar filament.
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4
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Abstract
Syphilis is a chronic sexually transmitted disease caused by Treponema pallidum subsp. pallidum. Clinical manifestations separate the disease into stages; late stages of disease are now uncommon compared to the preantibiotic era. T. pallidum has an unusually small genome and lacks genes that encode many metabolic functions and classical virulence factors. The organism is extremely sensitive to environmental conditions and has not been continuously cultivated in vitro. Nonetheless, T. pallidum is highly infectious and survives for decades in the untreated host. Early syphilis lesions result from the host's immune response to the treponemes. Bacterial clearance and resolution of early lesions results from a delayed hypersensitivity response, although some organisms escape to cause persistent infection. One factor contributing to T. pallidum's chronicity is the paucity of integral outer membrane proteins, rendering intact organisms virtually invisible to the immune system. Antigenic variation of TprK, a putative surface-exposed protein, is likely to contribute to immune evasion. T. pallidum remains exquisitely sensitive to penicillin, but macrolide resistance has recently been identified in a number of geographic regions. The development of a syphilis vaccine, thus far elusive, would have a significant positive impact on global health.
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Affiliation(s)
- Rebecca E Lafond
- Department of Medicine, Box 359779, Harborview Medical Center, 325 Ninth Ave., Seattle, WA 98104, USA
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5
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Abstract
Although spirochete periplasmic flagella have many features similar to typical bacterial flagella, they are unique in their structure and internal periplasmic location. This location provides advantages for pathogenic spirochetes to enter and to adapt in the appropriate host, and to penetrate through matrices that inhibit the motility of most other bacteria. These flagella are complex, and they dynamically interact with the spirochete cell cylinder in novel ways. Electron microscopy, tomography and three-dimensional reconstructions have provided new insights into flagellar structure and its relationship to the spirochetal cell cylinder. Recent advances in genetic methods have begun to shed light on the composition of the spirochete flagellum, and on the regulation of its synthesis. Because spirochetes have a high length to width ratio, their cells provide an opportunity to study two important features. These include the polarity or distribution of flagellar synthesis as well as the mechanisms required for coordination of the movement of the cell ends, to enable it to move in the forward or reverse direction.
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Affiliation(s)
- Ronald J Limberger
- Wadsworth Center-Axelrod Institute, New York State Department of Health, Albany, N Y 12201, USA.
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6
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Sato T, Kuramitsu HK. Polymerase chain reaction for the detection of flaA-1 genes of oral spirochaetes in human advanced periodontal pockets. Arch Oral Biol 2000; 45:921-5. [PMID: 10973566 DOI: 10.1016/s0003-9969(00)00058-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel group of oral spirochaetes that were specifically labeled by H9-2, a monoclonal antibody against the 37-kDa endoflagellar sheath protein of Treponema pallidum, have earlier been demonstrated in periodontitis-associated plaque samples; two cultivable oral spirochaetes T. vincentii and T. medium displayed cross-reactivity with that monoclonal, but the molecular basis for this cross-reactivity is not yet defined. Here, the flaA-1 genes which encode the 37-kDa sheath protein from T. vincentii and the oral spirochaetes present in samples from advanced periodontitis were examined. A 856 bp fragment of the flaA-1 gene was amplified in T. pallidum and T. vincentii. The same-size polymerase chain reaction fragments were also amplified in two clinical samples from patients with advanced periodontitis but not from samples of healthy plaque. The sequences of the flaA-1 genes of the oral spirochaetes detected in human periodontal plaque were closely similar to those of T. pallidum and T. vincentii, but neither of these two organisms could be detected in these samples using rRNA-specific primers. The identity of the flaA-1 positive spirochaetes associated with periodontitis remains to be determined.
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Affiliation(s)
- T Sato
- Department of Oral Biology, State University of New York at Buffalo, 14214-3092, USA
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7
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Izard J, Samsonoff WA, Kinoshita MB, Limberger RJ. Genetic and structural analyses of cytoplasmic filaments of wild-type Treponema phagedenis and a flagellar filament-deficient mutant. J Bacteriol 1999; 181:6739-46. [PMID: 10542176 PMCID: PMC94139 DOI: 10.1128/jb.181.21.6739-6746.1999] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Unique cytoplasmic filaments are found in the treponeme genus of spirochete bacteria. Their function is unknown, but their location underneath the periplasmic flagellar filaments (PFF) suggests a role in motility and/or cell structure. To better understand these unique structures, the gene coding for the cytoplasmic filaments, cfpA, was identified in various treponemal species. Treponema phagedenis cfpA was 2,037 nucleotides long, and the encoded polypeptide showed 78 to 100% amino acid sequence identity with the partial sequence of CfpA from T. denticola, T. vincentii, and T. pallidum subsp. pertenue. Wild-type T. phagedenis and a PFF-deficient isolate were analyzed by electron microscopy to assess the structural relationship of the cytoplasmic filaments and the PFF. The number of cytoplasmic filaments per cell of T. phagedenis (mean, 5.7) was compared with the number of PFF at each end of the cell (mean, 4.7); the results suggest that there is no direct one-to-one correlation at the cell end. Moreover, a structural link between these structures could not be demonstrated. The cytoplasmic filaments were also analyzed by electron microscopy at different stages of cell growth; this analysis revealed that they are cleaved before or during septum formation and before the nascent formation of PFF. A PFF-deficient mutant of T. phagedenis possessed cytoplasmic filaments similar to those of the wild type, suggesting that intact PFF are not required for their assembly and regulation. The extensive conservation of CfpA among pathogenic spirochetes suggests an important function, and structural analysis suggests that it is unlikely that the cytoplasmic filaments and the flagellar apparatus are physically linked.
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Affiliation(s)
- J Izard
- David Axelrod Institute for Public Health, Wadsworth Center, New York State Department of Health, Albany, New York 12201-2002, USA.
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8
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Chi B, Chauhan S, Kuramitsu H. Development of a system for expressing heterologous genes in the oral spirochete Treponema denticola and its use in expression of the Treponema pallidum flaA gene. Infect Immun 1999; 67:3653-6. [PMID: 10377154 PMCID: PMC116559 DOI: 10.1128/iai.67.7.3653-3656.1999] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The present communication describes the construction of a new Escherichia coli-Treponema denticola shuttle vector based on the naturally occurring spirochete plasmid pTS1 and the expression of the heterologous T. pallidum flaA gene from the plasmid in T. denticola. This new shuttle vector system should prove useful in characterizing virulence factors from unculturable pathogenic spirochetes.
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Affiliation(s)
- B Chi
- Department of Oral Biology, State University of New York at Buffalo, Buffalo, New York 14214, USA
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9
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Shevchenko DV, Sellati TJ, Cox DL, Shevchenko OV, Robinson EJ, Radolf JD. Membrane topology and cellular location of the Treponema pallidum glycerophosphodiester phosphodiesterase (GlpQ) ortholog. Infect Immun 1999; 67:2266-76. [PMID: 10225883 PMCID: PMC115966 DOI: 10.1128/iai.67.5.2266-2276.1999] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent reports that isolated Treponema pallidum outer membranes contain an ortholog for glycerophosphodiester phosphodiesterase (GlpQ) (D. V. Shevchenko, D. R. Akins, E. J. Robinson, M. Li, O. V. Shevchenko, and J. D. Radolf, Infect. Immun. 65:4179-4189, 1997) and that this protein is a potential opsonic target for T. pallidum (C. E. Stebeck, J. M. Shaffer, T. W. Arroll, S. A. Lukehart, and W. C. Van Voorhis, FEMS Microbiol. Lett. 154:303-310, 1997) prompted a more detailed investigation of its physicochemical properties and cellular location. [14C]palmitate radiolabeling studies of a GlpQ-alkaline phosphatase fusion expressed in Escherichia coli confirmed the prediction from DNA sequencing that the protein is lipid modified. Studies using Triton X-114 phase partitioning revealed that the protein's amphiphilicity is due to lipid modification and that a substantial portion of the polypeptide is associated with the T. pallidum peptidoglycan sacculus. Three different approaches, i.e., (i) proteinase K treatment of intact treponemes, (ii) indirect immunofluorescence analysis of treponemes encapsulated in agarose beads, and (iii) opsonophagocytosis of treponemes incubated with antiserum against recombinant GlpQ by rabbit peritoneal macrophages, confirmed that GlpQ is entirely subsurface in T. pallidum. Moreover, rabbits hyperimmunized with GlpQ were not protected against intradermal challenge with virulent treponemes. Circular dichroism spectroscopy confirmed that the recombinant form of the polypeptide lacked discernible evidence of denaturation. Finally, GlpQ was not radiolabeled when T. pallidum outer membranes were incubated with 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)-diazarene, a photoactivatable, lipophilic probe which promiscuously labels both proteins and lipids within phospholipid bilayers. Taken as a whole, these studies indicate that the T. pallidum GlpQ ortholog is a periplasmic protein associated predominantly with the spirochete's peptidoglycan-cytoplasmic membrane complex.
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Affiliation(s)
- D V Shevchenko
- Departments of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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10
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Fraser CM, Norris SJ, Weinstock GM, White O, Sutton GG, Dodson R, Gwinn M, Hickey EK, Clayton R, Ketchum KA, Sodergren E, Hardham JM, McLeod MP, Salzberg S, Peterson J, Khalak H, Richardson D, Howell JK, Chidambaram M, Utterback T, McDonald L, Artiach P, Bowman C, Cotton MD, Fujii C, Garland S, Hatch B, Horst K, Roberts K, Sandusky M, Weidman J, Smith HO, Venter JC. Complete genome sequence of Treponema pallidum, the syphilis spirochete. Science 1998; 281:375-88. [PMID: 9665876 DOI: 10.1126/science.281.5375.375] [Citation(s) in RCA: 697] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The complete genome sequence of Treponema pallidum was determined and shown to be 1,138,006 base pairs containing 1041 predicted coding sequences (open reading frames). Systems for DNA replication, transcription, translation, and repair are intact, but catabolic and biosynthetic activities are minimized. The number of identifiable transporters is small, and no phosphoenolpyruvate:phosphotransferase carbohydrate transporters were found. Potential virulence factors include a family of 12 potential membrane proteins and several putative hemolysins. Comparison of the T. pallidum genome sequence with that of another pathogenic spirochete, Borrelia burgdorferi, the agent of Lyme disease, identified unique and common genes and substantiates the considerable diversity observed among pathogenic spirochetes.
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Affiliation(s)
- C M Fraser
- Institute for Genomic Research, Rockville, MD 20850, USA.
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11
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Ge Y, Li C, Corum L, Slaughter CA, Charon NW. Structure and expression of the FlaA periplasmic flagellar protein of Borrelia burgdorferi. J Bacteriol 1998; 180:2418-25. [PMID: 9573194 PMCID: PMC107184 DOI: 10.1128/jb.180.9.2418-2425.1998] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/1997] [Accepted: 03/03/1998] [Indexed: 02/07/2023] Open
Abstract
The spirochete which causes Lyme disease, Borrelia burgdorferi, has many features common to other spirochete species. Outermost is a membrane sheath, and within this sheath are the cell cylinder and periplasmic flagella (PFs). The PFs are subterminally attached to the cell cylinder and overlap in the center of the cell. Most descriptions of the B. burgdorferi flagellar filaments indicate that these organelles consist of only one flagellin protein (FlaB). In contrast, the PFs from other spirochete species are comprised of an outer layer of FlaA and a core of FlaB. We recently found that a flaA homolog was expressed in B. burgdorferi and that it mapped in a fla/che operon. These results led us to analyze the PFs and FlaA of B. burgdorferi in detail. Using Triton X-100 to remove the outer membrane and isolate the PFs, we found that the 38.0-kDa FlaA protein purified with the PFs in association with the 41.0-kDa FlaB protein. On the other hand, purifying the PFs by using Sarkosyl resulted in no FlaA in the isolated PFs. Sarkosyl has been used by others to purify B. burgdorferi PFs, and our results explain in part their failure to find FlaA. Unlike other spirochetes, B. burgdorferi FlaA was expressed at a lower level than FlaB. In characterizing FlaA, we found that it was posttranslationally modified by glycosylation, and thus it resembles its counterpart from Serpulina hyodysenteriae. We also tested if FlaA was synthesized in a spontaneously occurring PF mutant of B. burgdorferi (HB19Fla-). Although this mutant still synthesized flaA message in amounts similar to the wild-type amounts, it failed to synthesize FlaA protein. These results suggest that, in agreement with data found for FlaB and other spirochete flagellar proteins, FlaA is likely to be regulated on the translational level. Western blot analysis using Treponema pallidum anti-FlaA serum indicated that FlaA was antigenically well conserved in several spirochete species. Taken together, the results indicate that both FlaA and FlaB comprise the PFs of B. burgdorferi and that they are regulated differently from flagellin proteins of other bacteria.
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Affiliation(s)
- Y Ge
- Department of Microbiology and Immunology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown 26506-9177, USA
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Lin M, Surujballi O, Nielsen K, Nadin-Davis S, Randall G. Identification of a 35-kilodalton serovar-cross-reactive flagellar protein, FlaB, from Leptospira interrogans by N-terminal sequencing, gene cloning, and sequence analysis. Infect Immun 1997; 65:4355-9. [PMID: 9317049 PMCID: PMC175625 DOI: 10.1128/iai.65.10.4355-4359.1997] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
During the screening of antibodies to pathogenic leptospires, a murine monoclonal antibody (designated M138) was found to react with various serovars. An antigen of approximately 35 kDa from Leptospira interrogans serovar pomona, which reacted strongly with M138, was characterized by N-terminal amino acid sequencing and identified as a flagellin, a class B polypeptide subunit (FlaB) of the periplasmic flagella. The gene encoding the FlaB protein, flaB, was amplified from the genomic DNA of several pathogenic serovars by PCR with a single pair of oligonucleotide primers, suggesting that FlaB is highly conserved among these serovars. Cloning and sequence analysis of flaB from serovar pomona revealed that it contains an 849-bp open reading frame with a G + C content of 46.88% which encodes a 283-amino-acid protein with a calculated molecular mass of 31.297 kDa and a predicted pI of 9.065. A sequence comparison of flagellin proteins revealed that the amino acid sequence is most variable in the central portion of the serovar pomona FlaB, which is believed to contain specific sequence information and which may thus be useful in the design of DNA or synthetic peptide probes suitable for the detection of infection with pathogenic leptospires.
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Affiliation(s)
- M Lin
- Animal Diseases Research Institute, Nepean, Ontario, Canada
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13
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Akins DR, Robinson E, Shevchenko D, Elkins C, Cox DL, Radolf JD. Tromp1, a putative rare outer membrane protein, is anchored by an uncleaved signal sequence to the Treponema pallidum cytoplasmic membrane. J Bacteriol 1997; 179:5076-86. [PMID: 9260949 PMCID: PMC179365 DOI: 10.1128/jb.179.16.5076-5086.1997] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Treponema pallidum rare outer membrane protein 1 (Tromp1) has extensive sequence homology with substrate-binding proteins of ATP-binding cassette transporters. Because such proteins typically are periplasmic or cytoplasmic membrane associated, experiments were conducted to clarify Tromp1's physicochemical properties and cellular location in T. pallidum. Comparison of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobilities of (i) native Tromp1 and Tromp1 synthesized by coupled in vitro transcription-translation and (ii) native Tromp1 and recombinant Tromp1 lacking the N-terminal signal sequence revealed that the native protein is not processed. Other studies demonstrated that recombinant Tromp1 lacks three basic porin-like properties: (i) the ability to form aqueous channels in liposomes which permit the influx of small hydrophilic solutes, (ii) an extensive beta-sheet secondary structure, and (iii) amphiphilicity. Subsurface localization of native Tromp1 was demonstrated by immunofluorescence analysis of treponemes encapsulated in gel microdroplets, while opsonization assays failed to detect surface-exposed Tromp1. Incubation of motile treponemes with 3-(trifluoromethyl)-3-(m-[125I]iodophenyl)-diazarine, a photoactivatable, lipophilic probe, also did not result in the detection of Tromp1 within the outer membranes of intact treponemes but, instead, resulted in the labeling of a basic 30.5-kDa presumptive outer membrane protein. Finally, analysis of fractionated treponemes revealed that native Tromp1 is associated predominantly with cell cylinders. These findings comprise a body of evidence that Tromp1 actually is anchored by an uncleaved signal sequence to the periplasmic face of the T. pallidum cytoplasmic membrane, where it likely subserves a transport-related function.
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Affiliation(s)
- D R Akins
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235, USA
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14
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Hagman KE, Porcella SF, Popova TG, Norgard MV. Evidence for a methyl-accepting chemotaxis protein gene (mcp1) that encodes a putative sensory transducer in virulent Treponema pallidum. Infect Immun 1997; 65:1701-9. [PMID: 9125550 PMCID: PMC175201 DOI: 10.1128/iai.65.5.1701-1709.1997] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The clinical and histopathological manifestations of syphilis and the invasive behavior of Treponema pallidum in tissue culture systems reflect the propensity for treponemes to migrate through skin, hematogenously disseminate, and invade targeted tissues. Treponemal motility is believed to be essential to this process and thereby an important facet of syphilis pathogenesis. By analogy with other bacterial pathogens, it is plausible that treponemal motility and tissue invasion are modulated by sensory transduction events associated with chemotactic responses. Recent studies have demonstrated the existence in T. pallidum of accessory molecules typically associated with sensory transduction events involving methyl-accepting chemotaxis proteins (MCPs). Intrinsic radiolabeling of T. pallidum in vitro with L-[methyl-3H] methionine revealed one methylated treponemal polypeptide with an apparent molecular mass of 64 kDa. A degenerate oligonucleotide probe corresponding to a highly conserved C-terminal domain within Bacillus subtilis and Escherichia coli MCPs was used in Southern blotting of T. pallidum DNA to identify and subsequently clone a putative T. pallidum MCP gene (mcp1). Computer analyses predicted a near-consensus promoter upstream of mcp1, and primer extension analysis employing T. pallidum RNA revealed a transcriptional initiation site. T. pallidum mcp1 encoded a 579-amino-acid (64.6-kDa) polypeptide which was highly homologous to at least 69 other known or putative sensory transducer proteins, with the highest degrees of homology existing between the C terminus of mcp1 and the C-terminal (signaling) domains of the other bacterial MCPs. Other salient features of Mcp1 included (i) six potential membrane-spanning domains at the N terminus, (ii) two predicted alpha-helical coiled coil regions containing at least three putative methylation sites, and (iii) homologies with two ligand-binding domains (LI-1 and LI-2) of the E. coli MCPs Trg and Tar. This study is the first to provide both metabolic and genetic evidence for an MCP sensory transducer in T. pallidum. The combined findings prompt key questions regarding the relationship(s) among sensory transduction, regulation of endoflagellar rotation, and chemotactic responses (in particular, the role of glucose) during virulence expression by T. pallidum.
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Affiliation(s)
- K E Hagman
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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15
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Shevchenko DV, Akins DR, Robinson E, Li M, Popova TG, Cox DL, Radolf JD. Molecular characterization and cellular localization of TpLRR, a processed leucine-rich repeat protein of Treponema pallidum, the syphilis spirochete. J Bacteriol 1997; 179:3188-95. [PMID: 9150213 PMCID: PMC179096 DOI: 10.1128/jb.179.10.3188-3195.1997] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Automated Edman degradation was used to obtain N-terminal and internal amino acid sequences from a 26-kDa protein in isolated Treponema pallidum outer membranes (OMs). The resulting sequences enabled us to PCR amplify from T. pallidum DNA a 275-bp fragment of the corresponding gene. The complete nucleotide sequence of the gene was determined from fragments amplified by long-distance PCR. Primer extension verified the assigned translational start of the open reading frame (ORF) and putative upstream promoter elements. The ORF encoded a highly basic (pI 9.6) 26-kDa protein which contained an N-terminal 25-amino-acid leader peptide terminated by a signal peptidase I cleavage site. The mature protein contained seven tandemly spaced copies (as well as an eighth incomplete copy) of a leucine-rich repeat (LRR), a motif previously identified in a number of prokaryotic and eukaryotic proteins. Accordingly, the polypeptide was designated T. pallidum leucine-rich repeat protein (TpLRR). Although Triton X-114 phase partitioning showed that TpLRR was hydrophilic, cell localization studies showed that most of the antigen was associated with the peptidoglycan-cytoplasmic membrane complex rather than being freely soluble in the periplasmic space. Immunoblot studies showed that syphilis patients develop a weak antibody response to the antigen. Lastly, the lrr(T. pallidum) gene was mapped to a 60-kb SfiI-SpeI fragment of the T. pallidum chromosome which also contains the rrnA and flaA genes. The function(s) of TpLRR is currently unknown; however, protein-protein and/or protein-lipid interactions mediated by its LRR motifs may facilitate interactions between components of the T. pallidum cell envelope.
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Affiliation(s)
- D V Shevchenko
- Department of Internal Medicine, U.T. Southwestern Medical Center at Dallas, Texas 75235, USA
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16
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You Y, Elmore S, Colton LL, Mackenzie C, Stoops JK, Weinstock GM, Norris SJ. Characterization of the cytoplasmic filament protein gene (cfpA) of Treponema pallidum subsp. pallidum. J Bacteriol 1996; 178:3177-87. [PMID: 8655496 PMCID: PMC178068 DOI: 10.1128/jb.178.11.3177-3187.1996] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Treponema pallidum and other members of the genera Treponema, Spirochaeta, and Leptonema contain multiple cytoplasmic filaments that run the length of the organism just underneath the cytoplasmic membrane. These cytoplasmic filaments have a ribbon-like profile and consist of a major cytoplasmic filament protein subunit (CfpA, formerly called TpN83) with a relative molecular weight of approximately 80,000. Degenerate DNA primers based on N-terminal and CNBr cleavage fragment amino acid sequences of T. pallidum subsp. pallidum (Nichols) CfpA were utilized to amplify a fragment of the encoding gene (cfpA). A 6.8-kb EcoRI fragment containing all but the 5' end of cfpA was identified by hybridization with the resulting PCR product and cloned into Lambda ZAP II. The 5' region was obtained by inverse PCR, and the complete gene sequence was determined. The cfpA sequence contained a 2,034-nucleotide coding region, a putative promoter with consensus sequences (5'-TTTACA-3' for -35 and 5'-TACAAT-3' for -10) similar to the sigma70 recognition sequence of Escherichia coli and other organisms, and a putative ribosome-binding site (5'-AGGAG-3'). The deduced amino acid sequence of CfpA indicated a protein of 678 residues with a calculated molecular mass of 78.5 kDa and an estimated pI of 6.15. No significant homology to known proteins or structural motifs was found among known prokaryotic or eukaryotic sequences. Expression of a LacZ-CfpA fusion protein in E. coli was detrimental to survival and growth of the host strain and resulted in the formation of short, irregular filaments suggestive of partial self-assembly of CfpA. The cytoplasmic filaments of T. pallidum and other spirochetes appear to represent a unique form of prokaryotic intracytoplasmic inclusions.
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Affiliation(s)
- Y You
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston 77225, USA
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17
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Radolf JD, Robinson EJ, Bourell KW, Akins DR, Porcella SF, Weigel LM, Jones JD, Norgard MV. Characterization of outer membranes isolated from Treponema pallidum, the syphilis spirochete. Infect Immun 1995; 63:4244-52. [PMID: 7591054 PMCID: PMC173603 DOI: 10.1128/iai.63.11.4244-4252.1995] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Previous freeze-fracture electron microscopy (EM) studies have shown that the outer membrane (OM) of Treponema pallidum contains sparse transmembrane proteins. One strategy for molecular characterization of these rare OM proteins involves isolation of T. pallidum OMs. Here we describe a simple and extremely gentle method for OM isolation based upon isopycnic sucrose density gradient ultracentrifugation of treponemes following plasmolysis in 20% sucrose. Evidence that T. pallidum OMs were isolated included (i) the extremely low protein/lipid ratio of the putative OM fraction, (ii) a paucity of antigenic and/or biochemical markers for periplasmic, cytoplasmic membrane, and cytosolic compartments, and (iii) freeze-fracture EM demonstrating that the putative OMs contained intramembranous particles highly similar in size and density to those in native T. pallidum OMs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that the OMs contained a relatively small number of treponemal proteins, including several which did not appear to correspond to previously characterized T. pallidum antigens. Interestingly, these candidate rare OM proteins reacted poorly with syphilitic sera as determined by both conventional immunoblotting and enhanced chemiluminescence. Compared with whole cells, T. pallidum OMs were deficient in cardiolipin, the major lipoidal antigen reactive with antibodies in syphilitic sera. Also noteworthy was that other lipoidal constituents of OMs, including the recently discovered glycolipids, did not react with human syphilitic sera. These latter observations suggest that the poor antigenicity of virulent T. pallidum is a function of both the lipid composition and the low protein content of its OM.
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Affiliation(s)
- J D Radolf
- Department of Internal Medicine, U.T. Southwestern Medical Center, Dallas 75235, USA
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18
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Rosey EL, Kennedy MJ, Petrella DK, Ulrich RG, Yancey RJ. Inactivation of Serpulina hyodysenteriae flaA1 and flaB1 periplasmic flagellar genes by electroporation-mediated allelic exchange. J Bacteriol 1995; 177:5959-70. [PMID: 7592350 PMCID: PMC177425 DOI: 10.1128/jb.177.20.5959-5970.1995] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Serpulina hyodysenteriae, the etiologic agent of swine dysentery, contains complex periplasmic flagella which are composed of multiple class A and class B polypeptides. To examine the role these proteins play in flagellar synthesis, structure, and function and to develop strains which may provide insight into the importance of motility in the etiology of this pathogen, we constructed specific periplasmic flagellar mutations in S. hyodysenteriae B204. The cloned flaA1 and flaB1 genes were disrupted by replacement of internal fragments with chloramphenicol and/or kanamycin gene cassettes. Following delivery of these suicide plasmids into S. hyodysenteriae, homologous recombination and allelic exchange at the targeted chromosomal flaA1 and flaB1 genes was verified by PCR, sequence, and Southern analysis. The utility of a chloramphenicol resistance gene cassette for targeted gene disruption was demonstrated and found more amenable than kanamycin as a selective marker in S. hyodysenteriae. Immunoblots of cell lysates of the flagellar mutants with antiserum raised against purified FlaA or FlaB confirmed the absence of the corresponding sheath or core protein. Both mutations selectively abolished expression of the targeted gene without affecting synthesis of the other flagellar polypeptide. flaA1 and flaB1 mutant strains exhibited altered motility in vitro and were less efficient in movement through a liquid medium. Paradoxically, isogenic strains containing specifically disrupted flaA1 or flaB1 alleles were capable of assembling periplasmic flagella that were morphologically normal as evidenced by electron microscopy. This is the first report of specific inactivation of a motility-associated gene in spirochetes.
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Affiliation(s)
- E L Rosey
- Upjohn Company, Kalamazoo, Michigan 49001, USA
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19
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Abstract
A lambda gt11 library constructed with Leptospira borgpetersenii DNA was screened with monoclonal antibodies (mAb) recognizing a periplasmic flagella-associated protein. A plaque expressing a fusion protein (lambda F15) which reacted with the mAb was isolated and the nucleotide sequence analyzed. The deduced amino-acid (aa) sequence indicates that the pfaP gene belongs to a group of bacterial genes whose products share aa sequence and possibly functional homologies with sppA, an Escherichia coli signal peptidase-encoding gene.
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Affiliation(s)
- G A Trueba
- Leptospirosis/Mycobacteriosis Research Unit, U.S. Department of Agriculture, National Animal Disease Center, Ames, IA 50010, USA
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20
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Walker EM, Howell JK, You Y, Hoffmaster AR, Heath JD, Weinstock GM, Norris SJ. Physical map of the genome of Treponema pallidum subsp. pallidum (Nichols). J Bacteriol 1995; 177:1797-804. [PMID: 7896703 PMCID: PMC176808 DOI: 10.1128/jb.177.7.1797-1804.1995] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A physical map of the chromosome of Treponema pallidum subsp. pallidum (Nichols), the causative agent of syphilis, was constructed from restriction fragments produced by NotI, SfiI, and SrfI. These rare-cutting restriction endonucleases cleaved the T. pallidum genome into 16, 8, and 15 fragments, respectively. Summation of the physical lengths of the fragments indicates that the chromosome of T. pallidum subsp. pallidum is approximately 1,030 to 1,080 kbp in size. The physical map was constructed by hybridizing a variety of probes to Southern blots of single and double digests of T. pallidum genomic DNA separated by contour-clamped homogeneous electric field electrophoresis. Probes included cosmid clones constructed from T. pallidum subsp. pallidum genomic DNA, restriction fragments excised from gels, and selected genes. Physical mapping confirmed that the chromosome of T. pallidum subsp. pallidum is circular, as the SfiI and SrfI maps formed complete circles. A total of 13 genes, including those encoding five membrane lipoproteins (tpn47, tpn41, tpn29-35, tpn17, and tpn15), a putative outer membrane porin (tpn50), the flagellar sheath and hook proteins (flaA and flgE), the cytoplasmic filament protein (cfpA), 16S rRNA (rrnA), a major sigma factor (rpoD), and a homolog of cysteinyl-tRNA synthetase (cysS), have been localized in the physical map as a first step toward studying the genetic organization of this noncultivable pathogen.
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Affiliation(s)
- E M Walker
- Department of Pathology and Laboratory Medicine, University of Texas Medical School at Houston 77225
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21
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Cox DL, Akins DR, Porcella SF, Norgard MV, Radolf JD. Treponema pallidum in gel microdroplets: a novel strategy for investigation of treponemal molecular architecture. Mol Microbiol 1995; 15:1151-64. [PMID: 7623668 DOI: 10.1111/j.1365-2958.1995.tb02288.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Controversy exists regarding the constituents and antigenic properties of the Treponema pallidum outer membrane; a major point of contention concerns the cellular location(s) of the spirochaete's lipoprotein immunogens. To address these issues and circumvent problems associated with prior efforts to localize treponemal surface antigens, we developed a novel strategy for investigating T. pallidum molecular architecture. Virulent treponemes were encapsulated in porous agarose beads (gel microdroplets) and then probed in the presence or absence of Triton X-100. Intact, encapsulated treponemes were not labelled by monospecific antisera directed against four major T. pallidum lipoproteins or a candidate T. pallidum outer membrane protein (TpN50) with C-terminal sequence homology to Escherichia coli OmpA or by human or rabbit syphilitic serum. Each of these immunologic reagents, however, labelled encapsulated treponemes co-incubated with detergent. In contrast, antibodies generated against isolated T. pallidum outer membranes labelled intact organisms and the pattern of fluorescence was consistent with the distribution of rare outer membrane proteins visualized by freeze-fracture electron microscopy. In addition to providing strong evidence that the protein portions of treponemal lipoproteins are located within the periplasmic space, these studies have extended our understanding of the topographical relationships among T. pallidum cell envelope constituents. They also demonstrate the feasibility of generating antibodies against rare outer membrane proteins and detecting them on the surfaces of virulent treponemes.
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Affiliation(s)
- D L Cox
- Division of STD Laboratory Research, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA
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22
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Limberger RJ, Slivienski LL, Samsonoff WA. Genetic and biochemical analysis of the flagellar hook of Treponema phagedenis. J Bacteriol 1994; 176:3631-7. [PMID: 8206841 PMCID: PMC205552 DOI: 10.1128/jb.176.12.3631-3637.1994] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The periplasmic flagellum of Treponema phagedenis consists of the flagellar filament and hook-basal body. We report here a characterization of the hook gene and flagellar hook of T. phagedenis, and in the process of this analysis we found evidence that the hook polypeptide is likely cross-linked in situ. A T. phagedenis genomic library was screened with a Treponema pallidum antiserum, and the DNA segments from several positive plaques were subcloned and sequenced. DNA sequencing of two overlapping segments revealed a 1,389-nucleotide (nt) open reading frame (ORF) with a deduced amino acid sequence that was 36% identical to that of FlgE, the hook polypeptide of Salmonella typhimurium. This gene was designated T. phagedenis flgE. Beginning at 312 nt downstream from flgE was a partial ORF of 486 nt with a deduced amino acid sequence that was 33% identical to that of MotA of Bacillus subtilis, a polypeptide that enables flagellar rotation. Upstream of flgE, separated by 39 nt, was a partial (291-nt) ORF with a deduced amino acid sequence that was homologous to that of ORF8, a polypeptide of unknown function located in an operon encoding polypeptides involved in motility of B. subtilis. The T. phagedenis flgE gene was cloned into an Escherichia coli protein expression plasmid, and the purified recombinant protein was used to prepare a FlgE antiserum. Western blots (immunoblots) of whole-cell lysates probed with this antiserum revealed a 55-kDa polypeptide and a ladder of polypeptide bands with increasing molecular masses. T. phagedenis hooks were then isolated and purified, and electron microscopic analysis revealed that the morphology of the hooks resembled that in other bacteria. The hooks were slightly curved and had an average length of 69 +/- 8 nm and a diameter of 23 +/- 1 nm. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blots of purified hook preparations using the FlgE antiserum also revealed a polypeptide ladder, suggesting that the hooks are composed of a covalently cross-linked polypeptide.
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Affiliation(s)
- R J Limberger
- David Axelrod Institute for Public Health, Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509
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23
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Becker PS, Akins DR, Radolf JD, Norgard MV. Similarity between the 38-kilodalton lipoprotein of Treponema pallidum and the glucose/galactose-binding (MglB) protein of Escherichia coli. Infect Immun 1994; 62:1381-91. [PMID: 8132345 PMCID: PMC186291 DOI: 10.1128/iai.62.4.1381-1391.1994] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The recent discovery that abundant and immunogenic lipoproteins constitute the integral membrane proteins of Treponema pallidum has prompted efforts to investigate their importance in the physiology and ultrastructure of the organism and in immune responses during infection. Earlier studies identified a 38-kDa lipoprotein of T. pallidum believed to be specific to the pathogen. In the present study, monoclonal antibodies generated against the 38-kDa lipoprotein of T. pallidum reacted with cognate 37-kDa molecules in the nonpathogens Treponema phagedenis, Treponema denticola, and Treponema refringens. Cloning and expression of the 38-kDa-lipoprotein gene of T. pallidum in Escherichia coli revealed that the recombinant product displayed a slightly larger (39-kDa) apparent molecular mass but remained reactive with anti-38-kDa-protein monoclonal antibodies. The recombinant product was processed and acylated in E. coli. DNA and amino acid sequence analyses indicated an open reading frame encoding 403 amino acids, with the first 25 amino acids corresponding to a leader peptide terminated by a signal peptidase II processing site of Val-Val-Gly-Cys. The predicted mature protein is 378 amino acids in length with a deduced molecular weight of 40,422 (excluding acylation). Southern blotting failed to demonstrate in nonpathogenic treponemes genomic sequences homologous with the 38-kDa-lipoprotein gene of T. pallidum. Computer analysis revealed that the 38-kDa lipoprotein of T. pallidum had 34.2% identity and 58.9% similarity with the glucose/galactose-binding protein (MglB) of E. coli and Salmonella typhimurium. Furthermore, of the 19 amino acids of MglB involved in carbohydrate binding, the 38-kDa lipoprotein had identity with 11. These studies have allowed the first putative functional assignment (carbohydrate binding) to a T. pallidum integral membrane protein. Recognition of this potential physiological role for the 38-kDa lipoprotein underscores the possibility that the membrane biology of T. pallidum may more closely resemble that of gram-positive organisms, which also utilize lipoproteins as anchored transporters, than that of gram-negative bacteria to which T. pallidum often is analogized.
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Affiliation(s)
- P S Becker
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235
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24
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Anda P, Backenson PB, Coleman JL, Benach JL. Epitopes shared by unrelated antigens of Borrelia burgdorferi. Infect Immun 1994; 62:1070-8. [PMID: 7509314 PMCID: PMC186226 DOI: 10.1128/iai.62.3.1070-1078.1994] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
An immunoglobulin M kappa-chain murine monoclonal antibody (CAB) reacted in a Western blot (immunoblot) with approximately 30 polypeptides from a whole-cell lysate of several American and European Borrelia burgdorferi strains. The reactive antigen with the highest M(r) was measured at 93 kDa (p93) and had an NH2-terminal sequence identical to the one previously reported for this antigen. The lowest reactive antigen had an M(r) of 16,000. All antigens recognized by CAB had isoelectric points within a narrow acidic range, between 5.4 and 6.2. Thus, the objective of this study was to determine whether the broad reactivity of CAB could be due to degradation of the antigen with the highest M(r), since such spontaneous degradation of p93 has already been reported, and to determine whether CAB could recognize shared epitopes in different antigens. Treatment of B. burgdorferi with protease inhibitors did not result in changes in CAB reactivity, indicating that if such degradation existed, it was most likely not due to the action of endogenous proteases. Likewise, protease treatment of intact organisms and recovery of the antigens in the insoluble fraction of a Triton X-114 partition indicated that they were internal and thus less likely to be degraded by experimental procedures. Amino-terminal sequences of other reactive polypeptides showed one approximately 72-kDa polypeptide to be identical to the DnaK homolog of B. burgdorferi. Two other antigens at approximately 49 and 47 kDa were blocked to Edman degradation. Finally, one sequenced polypeptide with a molecular mass of approximately 38.5 kDa had a strong identity with glyceraldehyde-3-phosphate dehydrogenase of other bacteria and vertebrates. Thus, while it cannot be ruled out that some of the CAB reactivity may be due to fragmentation of p93, there is strong evidence to indicate the presence of a shared epitope in at least three, possibly five, unrelated antigens of B. burgdorferi. A linear epitope within amino acid residues 357 to 371 of p93 was identified. Evidence is presented for a discontinuous epitope in the carboxy-terminal region of the DnaK homolog, which bears strong amino acid identity with the p93 epitope. The conserved amino acid sequences necessary for these shared epitopes indicate possible genetic and/or functional relatedness among these various antigens.
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Affiliation(s)
- P Anda
- Centro Nacional de Microbiología, Virología e Inmunología Sanitarias, Instituto de Salud Carlos III, Madrid, Spain
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25
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Abstract
A combined physical and genetic map of the Serpulina hyodysenteriae B78T genome was constructed by using pulsed-field gel electrophoresis and DNA blot hybridizations. The S. hyodysenteriae genome is a single circular chromosome about 3.2 Mb in size. The physical map of the chromosome was constructed with the restriction enzymes BssHII, EclXI, NotI, SalI, and SmaI. The physical map was used to constructed a linkage map for genes encoding rRNA, flagellum subunit proteins, DNA gyrase, NADH oxidase, and three distinct hemolysins. Several flaB2-related loci, encoding core flagellum subunit proteins, were detected and are dispersed around the chromosome. The rRNA gene organization in S. hyodysenteriae is unusual. S. hyodysenteriae has one gene each for 5S (rrf), 16S (rrs), and 23S (rrl) rRNAs. The rrf and rrl genes are closely linked (within 5 kb), while the rrs gene is about 860 kb from the other two rRNA genes. Using a probe for the S. hyodysenteriae gyrA gene, we identified a possible location for the chromosomal replication origin. The size and genetic organization of the S. hyodysenteriae chromosome are different from those of previously characterized spirochetes.
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Affiliation(s)
- R L Zuerner
- Leptospirosis and Mycobacteriosis Research Unit, U.S. Department of Agriculture, Ames, Iowa 50010
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26
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Li Z, Dumas F, Dubreuil D, Jacques M. A species-specific periplasmic flagellar protein of Serpulina (Treponema) hyodysenteriae. J Bacteriol 1993; 175:8000-7. [PMID: 8253687 PMCID: PMC206980 DOI: 10.1128/jb.175.24.8000-8007.1993] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We have previously reported that a 46-kDa protein present in an outer membrane protein preparation seemed to be a species-specific antigen of Serpulina hyodysenteriae (Z. S. Li, N. S. Jensen, M. Bélanger, M.-C. L'Espérance, and M. Jacques, J. Clin. Microbiol. 30:2941-2947, 1992). The objective of this study was to further characterize this antigen. A Western blot (immunoblot) analysis and immunogold labeling with a monospecific antiserum against this protein confirmed that the protein was present in all S. hyodysenteriae reference strains but not in the nonpathogenic organism Serpulina innocens. The immunogold labeling results also indicated that the protein was associated with the periplasmic flagella of S. hyodysenteriae. N-terminal amino acid sequencing confirmed that the protein was in fact a periplasmic flagellar sheath protein. The molecular mass of this protein, first estimated to be 46 kDa by Western blotting, was determined to be 44 kDa when the protein was evaluated more precisely by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the protein was glycosylated, as determined by glycoprotein staining and also by N-glycosidase F treatment. Five other periplasmic flagellar proteins of S. hyodysenteriae, which may have been the core proteins and had molecular masses of 39, 35, 32, 30, and 29 kDa, were antigenically related and cross-reacted with the periplasmic flagellar proteins of S. innocens. Finally, serum from a pig experimentally infected with S. hyodysenteriae recognized the 44-kDa periplasmic flagellar sheath protein. Our results suggest that the 44-kDa periplasmic flagellar sheath protein of S. hyodysenteriae is a species-specific glycoprotein antigen.
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Affiliation(s)
- Z Li
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec, Canada
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27
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Sell S, Hsu PL. Delayed hypersensitivity, immune deviation, antigen processing and T-cell subset selection in syphilis pathogenesis and vaccine design. IMMUNOLOGY TODAY 1993; 14:576-82. [PMID: 8305130 DOI: 10.1016/0167-5699(93)90196-r] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
T-cell mediated delayed-type hypersensitivity (DTH) is the predominant immune mechanism for clearing tissues of infecting organisms in the primary lesion of syphilis. Here, Stewart Sell and Pei-Ling Hsu propose a strategy for vaccination against syphilis in which selective induction of DTH may be accomplished by using BCG vectored vaccines containing selected DNA sequences for T. pallidum antigens.
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Affiliation(s)
- S Sell
- Dept of Pathology, University of Texas Health Science Center, Houston 77030
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28
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Norris SJ. Polypeptides of Treponema pallidum: progress toward understanding their structural, functional, and immunologic roles. Treponema Pallidum Polypeptide Research Group. Microbiol Rev 1993; 57:750-79. [PMID: 8246847 PMCID: PMC372934 DOI: 10.1128/mr.57.3.750-779.1993] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Treponema pallidum subsp. pallidum, the spirochete that causes syphilis, is unusual in a number of respects, including its small genome size, inability to grow under standard in vitro culture conditions, microaerophilism, apparent paucity of outer membrane proteins, structurally complex periplasmic flagella, and ability to evade the host immune responses and cause disease over a period of years to decades. Many of these attributes are related ultimately to its protein content. Our knowledge of the activities, structure, and immunogenicity of its proteins has been expanded by the application of recombinant DNA, hybridoma, and structural fractionation techniques. The purpose of this monograph is to summarize and correlate this new information by using two-dimensional gel electrophoresis, monoclonal antibody reactivity, sequence data, and other properties as the bases of polypeptide identification. The protein profiles of the T. pallidum subspecies causing syphilis, yaws, and endemic syphilis are virtually indistinguishable but differ considerably from those of other treponemal species. Among the most abundant polypeptides are a group of lipoproteins of unknown function that appear to be important in the immune response during syphilitic infection. The periplasmic flagella of T. pallidum and other spirochetes are unique with regard to their protein content and ultrastructure, as well as their periplasmic location. They are composed of three core proteins (homologous to the other members of the eubacterial flagellin family) and a single, unrelated sheath protein; the functional significance of this arrangement is not understood at present. Although the bacterium contains the chaperonins GroEL and DnaK, these proteins are not under the control of the heat shock regulon as they are in most organisms. Studies of the immunogenicity of T. pallidum proteins indicate that many may be useful for immunodiagnosis and immunoprotection. Future goals in T. pallidum polypeptide research include continued elucidation of their structural locations and functional activities, identification and characterization of the low-abundance outer membrane proteins, further study of the immunoprotective and immunodiagnostic potential of T. pallidum proteins, and clarification of the roles of treponemal proteins in pathogenesis.
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Affiliation(s)
- S J Norris
- Department of Pathology, University of Texas Medical School at Houston 77225
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29
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Abstract
The flaA gene, which codes for the Spirochaeta aurantia flagellar filament outer layer polypeptide, FlaA, was cloned, sequenced and analysed. The gene appears to be transcribed into a monocistronic mRNA from a sigma 70-like promoter. The translational start is 31 base pairs after the start of the transcript, the open reading frame is 1011 base pairs, and a rho-independent-like transcription terminator sequence begins about 19 base pairs after the translational stop codon. The deduced amino acid sequence of the S. aurantia FlaA showed 40% identity with the Treponema pallidum FlaA, but these polypeptides did not show a significant similarity to other polypeptides for which sequence information was available.
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Affiliation(s)
- J Parales
- Department of Microbiology, University of Iowa, Iowa City 52242
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Limberger RJ, Slivienski LL, Yelton DB, Charon NW. Molecular genetic analysis of a class B periplasmic-flagellum gene of Treponema phagedenis. J Bacteriol 1992; 174:6404-10. [PMID: 1400192 PMCID: PMC207590 DOI: 10.1128/jb.174.20.6404-6410.1992] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Treponema phagedenis is a host-associated spirochete with multiple polypeptides making up its periplasmic flagella (PFs). Each PF has a 39-kDa polypeptide making up the sheath (class A PF polypeptide) and two to four antigenically similar 33- to 34-kDa polypeptide species making up the core (class B PF polypeptides). A genetic analysis of the PF-deficient mutants T-40 and T-55 has shown that the PFs are involved in motility. To better understand the synthesis and assembly of these complex organelles and to compare the PF genes with those of other spirochetes, we cloned and characterized the T. phagedenis flaB2 gene, which encodes one class B polypeptide. The flaB2 gene consists of an open reading frame of 858 nucleotides capable of encoding a protein of 31.5 kDa. The predicted amino acid sequence of the FlaB2 polypeptide was 92% identical to that of T. pallidum FlaB2, with a 76% identity at the nucleotide level. These results confirm previous immunological and N-terminal-sequence analyses which suggested that the PF genes are well conserved in the spirochetes. Primer extension analysis of T. phagedenis flaB2 indicated that the start site of transcription was 127 nucleotides upstream from the ATG initiation codon. Preceding the start site is a DNA sequence similar to the sigma 28 consensus promoter sequence commonly found associated with motility genes. Northern (RNA) blots probed with a segment of flaB2 DNA revealed a 1,000-nucleotide monocistronic transcript in the wild type and in PF-deficient mutants T-40 and T-55. DNA sequencing of most of the flaB2 gene of the mutants revealed no differences from the wild-type gene. Because the mutants fail to synthesize detectable class B PF polypeptides yet synthesize extensive amounts of flaB2 mRNA, PF synthesis in T. phagedenis is likely to involve regulation at the translational level.
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Affiliation(s)
- R J Limberger
- Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany 12201-0509
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31
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Trueba GA, Bolin CA, Zuerner RL. Characterization of the periplasmic flagellum proteins of Leptospira interrogans. J Bacteriol 1992; 174:4761-8. [PMID: 1624463 PMCID: PMC206273 DOI: 10.1128/jb.174.14.4761-4768.1992] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The structure and composition of periplasmic flagella (PF) from Leptospira interrogans serovar pomona type kennewicki were characterized. Electron microscopic observations showed that leptospiral PF were complex structures composed of an 11.3-nm-diameter core surrounded by two sheath layers with 21.5- and 42-nm diameters. Two-dimensional gel electrophoresis of isolated PF showed the presence of seven different proteins ranging in mass from 31.5 to 36 kDa. Rabbit polyclonal and mouse monoclonal antibodies against PF proteins were prepared and were used to localize specific proteins to portions of the PF structure by immunoelectron microscopy. A 34-kDa protein was associated with the 11.3-nm-diameter core filament, while a 36-kDa protein was associated with a PF sheath (21.5-nm-diameter filament). The amino termini of the 34- and 35.5-kDa proteins were homologous to PF core proteins of other spirochetes. The experimental data suggested that L. interrogans PF contains 2 proteins (34 and 35.5 kDa) in the PF core.
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Affiliation(s)
- G A Trueba
- Leptospirosis/Mycobacteriosis Research Unit, National Animal Disease Center, U.S. Department of Agriculture, Ames, Iowa
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32
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Koopman MB, de Leeuw OS, van der Zeijst BM, Kusters JG. Cloning and DNA sequence analysis of a Serpulina (Treponema) hyodysenteriae gene encoding a periplasmic flagellar sheath protein. Infect Immun 1992; 60:2920-5. [PMID: 1612759 PMCID: PMC257255 DOI: 10.1128/iai.60.7.2920-2925.1992] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
A Serpulina (Treponema) hyodysenteriae expression library was constructed in vector lambda ZAP and screened with a polyclonal antiserum raised against S. hyodysenteriae periplasmic flagella. A single immunoreactive plaque was chosen for further analysis. The recombinant phage from this plaque contained a gene encoding the 44-kDa protein that is on the outer layer (or sheath) of the periplasmic flagella. DNA sequence analysis showed that the gene encodes a protein of 320 amino acids. The protein is homologous to the flagellar sheath proteins of Treponema pallidum and Spirochaeta aurantia but not to any other flagellar proteins. We designated the cloned S. hyodysenteriae flagellar sheath protein gene flaA and the encoded protein FlaA. The 19 N-terminal amino acid residues of FlaA constitute a signal peptide that is cleaved from the protein before assembly onto the flagella in the periplasm. Amino acid residues 20 to 38 correspond to the N-terminal amino acid sequence of the native protein. Upstream from the gene, DNA motifs that are similar to the consensus Escherichia coli -35 and -10 promoter sequences and a ribosome binding site were identified. Downstream from the gene, two inverted repeat sequences that may serve as a rho-independent transcription termination signal are present.
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Affiliation(s)
- M B Koopman
- Department of Bacteriology, School of Veterinary Medicine, University of Utrecht, The Netherlands
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33
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Riviere GR, Elliot KS, Adams DF, Simonson LG, Forgas LB, Nilius AM, Lukehart SA. Relative Proportions of Pathogen-Related Oral Spirochetes (PROS) andTreponema denticolain Supragingival and Subgingival Plaque From Patients With Periodontitis. J Periodontol 1992; 63:131-6. [PMID: 1372653 DOI: 10.1902/jop.1992.63.2.131] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The purpose of this study was to use monoclonal antibodies to enumerate spirochetes in dental plaque, including the newly recognized pathogen-related oral spirochete (PROS) and specific serovars of Treponema denticola. Plaque was collected from control subjects with no apparent periodontal disease and from sites of moderate to severe chronic periodontitis in patients with inflammatory periodontal disease. Individual monoclonal antibodies were used to determine whether spirochetes were present and then a double-staining protocol was employed to count total spirochetes and specific treponemes in individual microscopic fields. Results indicate that spirochetes are more common at diseased sites and in subgingival plaque than at healthy sites or in supragingival plaque. Together PROS and T. denticola comprised the majority of all spirochetes in all samples and PROS and T. denticola serovars "B" and D were most numerous in plaque from patients with periodontitis. PROS were the majority of all spirochetes in supragingival plaque (76.2% +/- 23.8%) and subgingival plaque (60.9% +/- 19.1%) from periodontitis patients, significantly larger than the percentage of T. denticola serovar "B" (P less than .001 for both supragingival and subgingival plaque) and serovar D (P less than .01 for supragingival and P less than .001 for subgingival plaque). These observations indicate that PROS are the predominant spirochete in plaque from sites of patients with periodontitis, but other analytical approaches are necessary to determine if PROS or T. denticola are pathogenic.
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Affiliation(s)
- G R Riviere
- Department of Pediatric Dentistry, Oregon Health Sciences University, Portland
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Blanco DR, Giladi M, Champion CI, Haake DA, Chikami GK, Miller JN, Lovett MA. Identification of Treponema pallidum subspecies pallidum genes encoding signal peptides and membrane-spanning sequences using a novel alkaline phosphatase expression vector. Mol Microbiol 1991; 5:2405-15. [PMID: 1791755 DOI: 10.1111/j.1365-2958.1991.tb02086.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Treponema pallidum subspecies pallidum is a pathogenic spirochaete for which there are no systems of genetic exchange. In order to provide a system for the identification of T. pallidum surface proteins and potential virulence factors, we have developed a novel expression vector which confers the utility of TnphoA transposition. The relevant features of this plasmid vector, termed pMG, include an inducible tac promoter, a polylinker with multiple cloning sites in three reading frames, and an alkaline phosphatase (AP) gene lacking the signal sequence-encoding region. Library construction with Sau3A-digested T. pallidum genomic DNA resulted in the creation of functional T. pallidum-AP fusion proteins. Analysis of fusion proteins and their corresponding DNA and deduced amino acid sequences demonstrated that they could be grouped into three categories: (i) those with signal peptides containing leader peptidase I cleavage sites, (ii) those with signal peptides containing leader peptidase II cleavage sites, and (iii) those with non-cleavable hydrophobic membrane-spanning sequences. Triton X-114 detergent phase partitioning of individual T. pallidum-AP fusions revealed several clones whose AP activity partitioned preferentially into the hydrophobic detergent phase. Several of these fusion proteins were subsequently shown to be acylated by Escherichia coli following [3H]-palmitate labelling, indicating their lipoproteinaceous nature. DNA and amino acid sequence analysis of one acylated fusion protein, Tp75, confirmed the presence of a hydrophobic N-terminal signal sequence containing a consensus leader peptidase II recognition site. The DNA sequence of Tp75 also indicates that this is a previously unreported T. pallidum lipoprotein. T. pallidum-AP fusion proteins which partitioned into the hydrophobic detergent phase but did not incorporate palmitate were also identified. DNA and amino acid analysis of one such clone, Tp70, showed no cleavable signal but had a significant hydrophobic region of approximately 20 residues, consistent with a membrane-spanning domain. Immunoblot analysis of T. pallidum-AP fusions detected with a monoclonal antibody specific for AP identified several fusion proteins which migrated as doublets separated in apparent electrophoretic mobility by no more than 3 kDa. [35S]-methionine pulse-chase incorporation showed that the doublet AP fusions represented precursor and processed forms of the same protein. DNA and amino acid sequence analysis of clones expressing processed fusion proteins demonstrated hydrophobic N-terminal signal sequences containing consensus leader peptidase I recognition sites.
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Affiliation(s)
- D R Blanco
- Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024
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Vidal M, Cairó J, Mateu MG, Villaverde A. Molecular cloning and expression of the VP1 gene of foot-and-mouth disease virus C1 in E. coli: effect on bacterial cell viability. Appl Microbiol Biotechnol 1991; 35:788-92. [PMID: 1369359 DOI: 10.1007/bf00169896] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The VP1 gene of foot-and-mouth disease virus (serotype C1) has been cloned in Escherichia coli Clts cells, under the control of the bacteriophage lambda pL promoter. The expressed VP1 protein was complete and non-fused, and its molecular weight was indistinguishable from that of the VP1 obtained from virions. Cells harbouring the recombinant vectors exhibited symptoms of plasmid instability and toxicity and died in a few weeks even when never exposed to inducing conditions. A new plasmid clone in which a segment of the VP1 gene was fused with contiguous genes of the viral genome was very stable. The expressed partial VP1 protein contains the two major immunogenic domains of the virion. This system can be used as a tool to design an immunogenic VP1, and to explore possible synthetic vaccines against foot-and-mouth disease.
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Affiliation(s)
- M Vidal
- Institut de Biologia Fonamental, Universitat Autònoma de Barcelona, Bellaterra, Spain
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Riviere GR, Wagoner MA, Baker-Zander SA, Weisz KS, Adams DF, Simonson L, Lukehart SA. Identification of spirochetes related to Treponema pallidum in necrotizing ulcerative gingivitis and chronic periodontitis. N Engl J Med 1991; 325:539-43. [PMID: 1713299 DOI: 10.1056/nejm199108223250803] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Spirochetes are commonly associated with periodontal disease, but it is not known whether these treponemes are pathogenic or merely opportunistic. We sought to determine whether spirochetes present in periodontal disease share antigens thought to be unique to spirochetes that are known pathogens. METHODS We examined dental plaque from 24 healthy subjects, from ulcerative sites in 17 patients with ulcerative gingivitis, and from areas of involvement in 19 patients with chronic periodontitis, using an immunocyto-chemical technique with monoclonal antibodies against pathogen-specific determinants on 47-kd and 37-kd molecules from Treponema pallidum subspecies pallidum. Serum was tested against T. pallidum by immunoblotting and by serologic assays for syphilis. RESULTS Spirochetes with a pathogen-specific epitope on a 47-kd molecule were not found in plaque samples from any of the 24 healthy subjects, but they were identified in plaque samples from 11 of 17 patients with ulcerative gingivitis (P less than 0.001) and from 10 of 19 patients with periodontitis (P less than 0.01). Monoclonal antibodies directed against a 37-kd molecule reacted with spirochetes in plaque samples from 1 of 14 controls, from all 11 patients with gingivitis from whom samples could be obtained (P less than 0.001), and from 14 of 19 patients with periodontitis (P less than 0.001). Five of 18 normal subjects had IgG against 47-kd and 37-kd molecules, but none had IgG against 14-kd or 12-kd molecules from T. pallidum subspecies pallidum. Among 19 patients with ulcerative gingivitis, IgG was identified against 47-kd molecules in 15, against 37-kd molecules in 12, against 14-kd molecules in 4, and against 12-kd molecules in 15. CONCLUSIONS The spirochetes found in dental plaque from patients with ulcerative gingivitis or chronic periodontitis have antigens that are thought to be unique to pathogenic treponemes. This close antigenic relation suggests that T. pallidum or a closely related organism may be involved in the pathogenesis of periodontal disease.
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Affiliation(s)
- G R Riviere
- Department of Pediatric Dentistry, School of Dentistry, Oregon Health Sciences University, Portland 97201-3097
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N-terminal amino acid sequences and amino acid compositions of the Spirochaeta aurantia flagellar filament polypeptides. J Bacteriol 1991; 173:1357-9. [PMID: 1991729 PMCID: PMC207265 DOI: 10.1128/jb.173.3.1357-1359.1991] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The amino-terminal sequences and amino acid compositions of the three major and two minor polypeptides constituting the filaments of Spirochaeta aurantia periplasmic flagella were determined. The amino-terminal sequence of the major 37.5-kDa outer layer polypeptide is identical to the sequence downstream of the proposed signal peptide of the protein encoded by the S. aurantia flaA gene. However, the amino acid composition of the 37.5-kDa polypeptide is not in agreement with that inferred from the sequence of flaA. The 34- and 31.5-kDa major filament core polypeptides and the 33- and 32-kDa minor core polypeptides show a striking similarity to each other, and the amino-terminal sequences of these core polypeptides show extensive identity with homologous proteins from members of other genera of spirochetes. An additional 36-kDa minor polypeptide that occurs occasionally in preparations of S. aurantia periplasmic flagella appears to be mixed with the 37.5-kDa outer layer polypeptide or a degradation product of this polypeptide.
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Isaacs RD, Radolf JD. Expression in Escherichia coli of the 37-kilodalton endoflagellar sheath protein of Treponema pallidum by use of the polymerase chain reaction and a T7 expression system. Infect Immun 1990; 58:2025-34. [PMID: 2194955 PMCID: PMC258771 DOI: 10.1128/iai.58.7.2025-2034.1990] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We previously reported the complete primary structure of the 37-kilodalton endoflagellar sheath protein (FlaA) of Treponema pallidum. However, we were unable to determine the nucleotide sequence of flaA upstream of amino acid 10. The desired nucleotide sequence was obtained by use of a strategy based upon the polymerase chain reaction and was found to contain a consensus Escherichia coli promoter, a ribosomal binding site, and a 20-amino-acid signal peptide. Expression of FlaA in E. coli was achieved by cloning polymerase chain reaction-derived constructs lacking the native T. pallidum promoter into a temperature-inducible T7 expression system. Pulse-chase and ethanol inhibition analyses of protein processing in E. coli cells and minicells, respectively, indicated that processing of the FlaA precursor was incomplete. Native and recombinant FlaA were identical as assessed by antibody reactivity and sodium dodecyl sulfate- and two-dimensional polyacrylamide gel electrophoretic mobilities. Soluble FlaA was not detected in either the cytoplasmic or the periplasmic fractions of E. coli transformants. Fractionation of E. coli cell envelopes unexpectedly revealed that FlaA precursor and FlaA were associated with both the cytoplasmic and outer membranes. This is the first report of expression in E. coli of a T. pallidum protein which could not be cloned or expressed with its native promoter. Our data also indicate that information obtained in E. coli regarding the subcellular location of cloned treponemal proteins must be cautiously extrapolated to T. pallidum.
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Affiliation(s)
- R D Isaacs
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235
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Champion CI, Miller JN, Lovett MA, Blanco DR. Cloning, sequencing, and expression of two class B endoflagellar genes of Treponema pallidum subsp. pallidum encoding the 34.5- and 31.0-kilodalton proteins. Infect Immun 1990; 58:1697-704. [PMID: 2187805 PMCID: PMC258711 DOI: 10.1128/iai.58.6.1697-1704.1990] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Two structural endoflagellar genes of Treponema pallidum that encode the 34.5- and 31.0-kilodalton (kDa) polypeptides as detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were cloned, sequenced, and expressed. We designated these genes flaB1 and flaB3. A DNA sequence analysis of flaB1 and flaB3 showed that each gene possesses a single open reading frame that encodes a polypeptide; these polypeptides have molecular masses of 31.1 and 31.0 kDa, respectively. Shine-Dalgarno ribosome-binding sequences were identified upstream from the initiation codons of each gene. In addition, a single consensus promoter sequence was identified 121 base pairs upstream from the initiation codon of flaB1, suggesting polycistronic transcription of flaB1 and flaB3. Computer-induced alignment showed that the FlaB1 amino acid sequence was identical at 206 positions (72%) to the FlaB3 sequence. Both genes were subcloned into pATH vectors and were expressed under the control of the trpE promoter. The expression products of flaB1 and flaB3 revealed fusion proteins having molecular masses of 61.0 and 59.0 kDa, respectively, which were identified on immunoblots by using specific anti-T. pallidum endoflagellar serum.
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Affiliation(s)
- C I Champion
- Department of Microbiology and Immunology, University of California, Los Angeles 90024
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Gherardini FC, Hobbs MM, Stamm LV, Bassford PJ. Complementation of an Escherichia coli proC mutation by a gene cloned from Treponema pallidum. J Bacteriol 1990; 172:2996-3002. [PMID: 2188947 PMCID: PMC209099 DOI: 10.1128/jb.172.6.2996-3002.1990] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Little is known concerning the biosynthetic and metabolic capabilities of the syphilis agent, Treponema pallidum, because of the inability to cultivate continuously the organism in vitro. To circumvent the problem of cultivation, researchers have used recombinant DNA technology to express treponemal protein antigens in Escherichia coli. However, with a few notable exceptions, the specific cellular roles of these cloned treponemal proteins have not been determined. In this study, a cosmid library of T. pallidum genomic DNA was constructed and amplified by repackaging infective lambda bacteriophage particles in vivo. Recombinant clones capable of complementing a null mutation in the E. coli proC gene encoding 1-pyrroline-5-carboxylate (P5C) reductase (EC 1.5.1.2) were subsequently identified. The complementing activity was eventually localized to a 2.3-kilobase BglII-HindIII fragment that hybridized to the same-size fragment of a BglII-HindIII digest of T. pallidum DNA. Two proteins of 41 and 27 kilodaltons (kDa) were encoded by this fragment, as determined by maxicell analysis. Although only the 41-kDa protein could be specifically precipitated by experimental syphilitic rabbit antisera, it was the 27-kDa protein that was responsible for the proC-complementing activity. The recombinant P5C reductase differed from the native E. coli enzyme by a number of biochemical properties. The cloning of a T. pallidum gene encoding P5C reductase strongly suggests that this pathogen has the ability to synthesize proline and possibly other amino acids.
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Affiliation(s)
- F C Gherardini
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill 27599-7290
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