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Abstract
Most bacterial species express one or more extracellular organelles called pili/fimbriae that are required for many properties of each bacterial cell. The Neisseria gonorrhoeae type IV pilus is a major virulence and colonization factor for the sexually transmitted infection gonorrhea. We have discovered a new protein of Neisseria gonorrhoeae called TfpC that is required to maintain type IV pili on the bacterial cell surface. There are similar proteins found in other members of the Neisseria genus and many other bacterial species important for human health. Neisseria gonorrhoeae relies on type IV pili (T4p) to promote colonization of their human host and to cause the sexually transmitted infection gonorrhea. This organelle cycles through a process of extension and retraction back into the bacterial cell. Through a genetic screen, we identified the NGO0783 locus of N. gonorrhoeae strain FA1090 as containing a gene encoding a protein required to stabilize the type IV pilus in its extended, nonretracted conformation. We have named the gene tfpC and the protein TfpC. Deletion of tfpC produces a nonpiliated colony morphology, and immuno-transmission electron microscopy confirms that the pili are lost in the ΔtfpC mutant, although there is some pilin detected near the bacterial cell surface. A copy of the tfpC gene expressed from a lac promoter restores pilus expression and related phenotypes. A ΔtfpC mutant shows reduced levels of pilin protein, but complementation with a tfpC gene restored pilin to normal levels. Bioinformatic searches show that there are orthologues in numerous bacterial species, but not all type IV pilin-expressing bacteria contain orthologous genes. Coevolution and nuclear magnetic resonance (NMR) analysis indicates that TfpC contains an N-terminal transmembrane helix, a substantial extended/unstructured region, and a highly charged C-terminal coiled-coil domain.
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PacBio Amplicon Sequencing Method To Measure Pilin Antigenic Variation Frequencies of Neisseria gonorrhoeae. mSphere 2019; 4:4/5/e00562-19. [PMID: 31578246 PMCID: PMC6796969 DOI: 10.1128/msphere.00562-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Gene diversification is a common mechanism pathogens use to alter surface structures to aid in immune avoidance. Neisseria gonorrhoeae uses a gene conversion-based diversification system to alter the primary sequence of the gene encoding the major subunit of the pilus, pilE Antigenic variation occurs when one of the nonexpressed 19 silent copies donates part of its DNA sequence to pilE We have developed a method using Pacific Biosciences (PacBio) amplicon sequencing and custom software to determine pilin antigenic variation frequencies. The program analyzes 37 variable regions across the strain FA1090 1-81-S2 pilE gene and can be modified to determine sequence variation from other starting pilE sequences or other diversity generation systems. Using this method, we measured pilin antigenic variation frequencies for various derivatives of strain FA1090 and showed we can also analyze pilin antigenic variation frequencies during macrophage infection.IMPORTANCE Diversity generation systems are used by many unicellular organism to provide subpopulations of cell with different properties that are available when needed. We have developed a method using the PacBio DNA sequencing technology and a custom computer program to analyze the pilin antigenic variation system of the organism that is the sole cause of the sexually transmitted infection, gonorrhea.
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Hockenberry AM, Post DMB, Rhodes KA, Apicella M, So M. Perturbing the acetylation status of the Type IV pilus retraction motor, PilT, reduces Neisseria gonorrhoeae viability. Mol Microbiol 2018; 110:677-688. [PMID: 29719082 DOI: 10.1111/mmi.13979] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 04/29/2018] [Indexed: 02/07/2023]
Abstract
Post-translational acetylation is a common protein modification in bacteria. It was recently reported that Neisseria gonorrhoeae acetylates the Type IV pilus retraction motor, PilT. Here, we show recombinant PilT can be acetylated in vitro and acetylation does not affect PilT ultrastructure. To investigate the function of PilT acetylation, we mutated an acetylated lysine, K117, to mimic its acetylated or unacetylated forms. These mutations were not tolerated by wild-type N. gonorrhoeae, but they were tolerated by N. gonorrhoeae carrying an inducible pilE when grown without inducer. We identified additional mutations in pilT and pilU that suppress the lethality of K117 mutations. To investigate the link between PilE and PilT acetylation, we found the lack of PilE decreases PilT acetylation levels and increases the amount of PilT associated with the inner membrane. Finally, we found no difference between wild-type and mutant cells in transformation efficiency, suggesting neither mutation inhibits Type IV pilus retraction. Mutant cells, however, form microcolonies morphologically distinct from wt cells. We conclude that interfering with the acetylation status of PilTK117 greatly reduces N. gonorrhoeae viability, and mutations in pilT, pilU and pilE can overcome this lethality. We discuss the implications of these findings in the context of Type IV pilus retraction regulation.
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Affiliation(s)
- Alyson M Hockenberry
- Department of Immunobiology and BIO5 Institute, University of Arizona, Tucson, AZ, 85719, USA
| | | | - Katherine A Rhodes
- Department of Immunobiology and BIO5 Institute, University of Arizona, Tucson, AZ, 85719, USA
| | - Michael Apicella
- Department of Microbiology, The University of Iowa, Iowa City, IA, USA
| | - Magdalene So
- Department of Immunobiology and BIO5 Institute, University of Arizona, Tucson, AZ, 85719, USA
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Oldewurtel ER, Kouzel N, Dewenter L, Henseler K, Maier B. Differential interaction forces govern bacterial sorting in early biofilms. eLife 2015; 4. [PMID: 26402455 PMCID: PMC4625442 DOI: 10.7554/elife.10811] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 09/23/2015] [Indexed: 12/30/2022] Open
Abstract
Bacterial biofilms can generate micro-heterogeneity in terms of surface structures. However, little is known about the associated changes in the physics of cell–cell interaction and its impact on the architecture of biofilms. In this study, we used the type IV pilus of Neisseria gonorrhoeae to test whether variation of surface structures induces cell-sorting. We show that the rupture forces between pili are fine-tuned by post-translational modification. Bacterial sorting was dependent on pilus post-translational modification and pilus density. Active force generation was necessary for defined morphologies of mixed microcolonies. The observed morphotypes were in remarkable agreement with the differential strength of adhesion hypothesis proposing that a tug-of-war among surface structures of different cells governs cell sorting. We conclude that in early biofilms the density and rupture force of bacterial surface structures can trigger cell sorting based on similar physical principles as in developing embryos. DOI:http://dx.doi.org/10.7554/eLife.10811.001 Communities of bacterial cells can live together embedded within a slime-like molecular matrix as a biofilm. This allows the bacteria to hide from external stresses. A single bacterium can replicate itself and develop into a biofilm, and over time the bacterial cells in specific regions of the biofilm will start to interact with their neighbors in different ways. These interactions occur via structures on the surface of the bacterial cells, and the differences in these interactions resemble those that occur as cells specialize during the development of animal embryos. Previous research into embryonic development has shown how differences in the physical interactions between embryonic cells are essential for sorting the cells into their correct locations and shaping the embryo. However, little is known about which processes govern the development of biofilms. Now, Oldewurtel et al. have asked whether differences in the physical interactions between bacteria trigger cell sorting during the early stages of biofilm development. The experiments involved measuring the force required to break the cell–cell connections (called the ‘rupture force’) in biofilms of a bacterium called Neisseria gonorrhoeae. Oldewurtel et al. found that, in agreement with previous predictions, physical interactions were important for sorting bacterial cells into clusters based on the structures on their surfaces. Bacterial cells actively pull on the surface structures of their neighbors, which allows the cells to sort themselves in a tug-of-war fashion. This means that a cell will move in the direction where it can pull the strongest (i.e., in the direction where the rupture force is highest). While bacteria and embryos use different molecules to generate these pulling forces, these findings indicate that the basic physical principles are similar in both systems. One of the next challenges will be to evaluate how biofilms might benefit from the structures that develop due to cell sorting. DOI:http://dx.doi.org/10.7554/eLife.10811.002
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Affiliation(s)
| | - Nadzeya Kouzel
- Department of Physics, University of Cologne, Cologne, Germany
| | - Lena Dewenter
- Department of Physics, University of Cologne, Cologne, Germany
| | - Katja Henseler
- Department of Physics, University of Cologne, Cologne, Germany
| | - Berenike Maier
- Department of Physics, University of Cologne, Cologne, Germany
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Eriksson J, Eriksson OS, Maudsdotter L, Palm O, Engman J, Sarkissian T, Aro H, Wallin M, Jonsson AB. Characterization of motility and piliation in pathogenic Neisseria. BMC Microbiol 2015; 15:92. [PMID: 25925502 PMCID: PMC4449605 DOI: 10.1186/s12866-015-0424-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 04/15/2015] [Indexed: 11/29/2022] Open
Abstract
Background The type IV pili (Tfp) of pathogenic Neisseria (i.e., N. gonorrhoeae and N. meningitidis) are essential for twitching motility. Tfp retraction, which is dependent on the ATPase PilT, generates the forces that move bacteria over surfaces. Neisseria motility has mainly been studied in N. gonorrhoeae whereas the motility of N. meningitidis has not yet been characterized. Results In this work, we analyzed bacterial motility and monitored Tfp retraction using live-cell imaging of freely moving bacteria. We observed that N. meningitidis moved over surfaces at an approximate speed of 1.6 μm/s, whereas N. gonorrhoeae moved with a lower speed (1.0 μm/s). An alignment of the meningococcal and gonococcal pilT promoters revealed a conserved single base pair variation in the −10 promoter element that influence PilT expression. By tracking mutants with altered pilT expression or pilE sequence, we concluded that the difference in motility speed was independent of both. Live-cell imaging using total internal reflection fluorescence microscopy demonstrated that N. gonorrhoeae more often moved with fewer visible retracting filaments when compared to N. meningitidis. Correspondingly, meningococci also displayed a higher level of piliation in transmission electron microscopy. Nevertheless, motile gonococci that had the same number of filaments as N. meningitidis still moved with a lower speed. Conclusions These data reveal differences in both speed and piliation between the pathogenic Neisseria species during twitching motility, suggesting a difference in Tfp-dynamics. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0424-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jens Eriksson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Olaspers Sara Eriksson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Lisa Maudsdotter
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Oskar Palm
- Theoretical Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
| | - Jakob Engman
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Tim Sarkissian
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Helena Aro
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
| | - Mats Wallin
- Theoretical Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
| | - Ann-Beth Jonsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Svante Arrhenius väg 20C, SE-10691, Stockholm, Sweden.
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Bacterial twitching motility is coordinated by a two-dimensional tug-of-war with directional memory. Nat Commun 2014; 5:3759. [PMID: 24806757 DOI: 10.1038/ncomms4759] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 03/31/2014] [Indexed: 02/07/2023] Open
Abstract
Type IV pili are ubiquitous bacterial motors that power surface motility. In peritrichously piliated species, it is unclear how multiple pili are coordinated to generate movement with directional persistence. Here we use a combined theoretical and experimental approach to test the hypothesis that multiple pili of Neisseria gonorrhoeae are coordinated through a tug-of-war. Based on force-dependent unbinding rates and pilus retraction speeds measured at the level of single pili, we build a tug-of-war model. Whereas the one-dimensional model robustly predicts persistent movement, the two-dimensional model requires a mechanism of directional memory provided by re-elongation of fully retracted pili and pilus bundling. Experimentally, we confirm memory in the form of bursts of pilus retractions. Bursts are seen even with bundling suppressed, indicating re-elongation from stable core complexes as the key mechanism of directional memory. Directional memory increases the surface range explored by motile bacteria and likely facilitates surface colonization.
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Abstract
Type IV pili (T4P) are multifunctional protein fibers produced on the surfaces of a wide variety of bacteria and archaea. The major subunit of T4P is the type IV pilin, and structurally related proteins are found as components of the type II secretion (T2S) system, where they are called pseudopilins; of DNA uptake/competence systems in both Gram-negative and Gram-positive species; and of flagella, pili, and sugar-binding systems in the archaea. This broad distribution of a single protein family implies both a common evolutionary origin and a highly adaptable functional plan. The type IV pilin is a remarkably versatile architectural module that has been adopted widely for a variety of functions, including motility, attachment to chemically diverse surfaces, electrical conductance, acquisition of DNA, and secretion of a broad range of structurally distinct protein substrates. In this review, we consider recent advances in this research area, from structural revelations to insights into diversity, posttranslational modifications, regulation, and function.
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Neisseria gonorrhoeae metalloprotease NGO1686 is required for full piliation, and piliation is required for resistance to H2O2- and neutrophil-mediated killing. mBio 2013; 4:mBio.00399-13. [PMID: 23839218 PMCID: PMC3735123 DOI: 10.1128/mbio.00399-13] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The sexually transmitted infection gonorrhea is caused exclusively by the human-specific pathogen Neisseria gonorrhoeae. Type IV pili are an essential virulence factor uniformly expressed on clinical gonococcal isolates and are required for several aspects of gonococcal pathogenesis, including adherence to host tissues, autoagglutination, twitching motility, and the uptake of DNA during transformation. Symptomatic gonococcal infection is characterized by the influx of neutrophils or polymorphonuclear leukocytes (PMNs) to the site of infection. PMNs are a key component of gonococcal pathogenesis, mediating the innate immune response through the use of oxidative and nonoxidative killing mechanisms. The M23B family zinc metallopeptidase NGO1686 is required for gonococci to survive oxidative killing by H2O2- and PMN-mediated killing through unknown mechanisms, but the only known target of NGO1686 is peptidoglycan. We report that the effect of NGO1686 on survival after exposure to H2O2 and PMNs is mediated through its role in elaborating pili and that nonpiliated mutants of N. gonorrhoeae are less resistant to killing by H2O2, LL-37, and PMNs than the corresponding piliated strains. These findings add to the various virulence-associated functions attributable to gonococcal pili and may explain the selection basis for piliation in clinical isolates of N. gonorrhoeae. IMPORTANCE Successful infectious agents need to overcome host defense systems to establish infection. We show that the Neisseria pilus, a major virulence factor of this organism, which causes gonorrhea, helps protect the bacterium from two major killing mechanisms used by the host to combat infections. We also show that to express the pilus, an enzyme needs to partially degrade the cell wall of the bacterium.
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Ramsey ME, Hackett KT, Kotha C, Dillard JP. New complementation constructs for inducible and constitutive gene expression in Neisseria gonorrhoeae and Neisseria meningitidis. Appl Environ Microbiol 2012; 78:3068-78. [PMID: 22327577 PMCID: PMC3346468 DOI: 10.1128/aem.07871-11] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/06/2012] [Indexed: 12/20/2022] Open
Abstract
We have created new complementation constructs for use in Neisseria gonorrhoeae and Neisseria meningitidis. The constructs contain regions of homology with the chromosome and direct the insertion of a gene of interest into the intergenic region between the genes iga and trpB. In order to increase the available options for gene expression in Neisseria, we designed the constructs to contain one of three different promoters. One of the constructs contains the isopropyl-β-d-thiogalactopyranoside-inducible lac promoter, which has been widely used in Neisseria. We also designed a construct that contains the strong, constitutive promoter from the gonococcal opaB gene. The third construct contains a tetracycline-inducible promoter, a novel use of this promoter in Neisseria. We demonstrate that anhydrotetracycline can be used to induce gene expression in the pathogenic Neisseria at very low concentrations and without negatively affecting the growth of the organisms. We use these constructs to complement an arginine auxotrophy in N. gonorrhoeae as well as to express a translational fusion of alkaline phosphatase with TraW. TraW is a component of the gonococcal type IV secretion system, and we demonstrate that TraW localizes to the periplasm.
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Affiliation(s)
- Meghan E Ramsey
- Department of Medical Microbiology and Immunology, University of Wisconsin—Madison School of Medicine and Public Health, Madison, Wisconsin, USA
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Structure/function analysis of Neisseria meningitidis PilW, a conserved protein that plays multiple roles in type IV pilus biology. Infect Immun 2011; 79:3028-35. [PMID: 21646452 DOI: 10.1128/iai.05313-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type IV pili (Tfp) are widespread filamentous bacterial organelles that mediate multiple functions and play a key role in pathogenesis in several important human pathogens, including Neisseria meningitidis. Tfp biology remains poorly understood at a molecular level because the roles of the numerous proteins that are involved remain mostly obscure. Guided by the high-resolution crystal structure we recently reported for N. meningitidis PilW, a widely conserved protein essential for Tfp biogenesis, we have performed a structure/function analysis by targeting a series of key residues through site-directed mutagenesis and analyzing the corresponding variants using an array of phenotypic assays. Here we show that PilW's involvement in the functionality of Tfp can be genetically uncoupled from its concurrent role in the assembly/stabilization of the secretin channels through which Tfp emerge on the bacterial surface. These findings suggest that PilW is a multifunctional protein.
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Bosch A, Prieto C, Serra DO, Martina P, Stämmbler M, Naumann D, Schmitt J, Yantorno O. Type-IV pili spectroscopic markers: applications in the quantification of piliation levels in Moraxella bovis cells by a FT-IR ANN-based model. JOURNAL OF BIOPHOTONICS 2010; 3:522-533. [PMID: 20422659 DOI: 10.1002/jbio.201000027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Type-IV pili are cell surface organelles found in a wide variety of Gram-negative bacteria. They have traditionally been detected by electron microscopy and ELISA techniques. However, these methodologies are not appropriate for the rapid discrimination and quantification of piliated and nonpiliated cells in industrial or field conditions. Here, the analysis of FT-IR spectra of piliated, nonpiliated and sheared Moraxella bovis cells, together with purified pili suspensions spectra, allowed the identification of 3 IR regions associated to spectroscopic markers of Type-IV pili: 1750-1600, 1450-1350 and 1280-950 cm(-1). Such IR-specific markers were found for piliated cells grown in different culture systems (liquid or solid media), independently of the strain or pili serotype. They were also sensitive to pili expression levels. Therefore, on the bases of these specific spectral features, an FT-IR ANN-based model was developed to classify piliation levels in 5 distinct groups. An overall classification rate of almost 90% demonstrates the strong potential of the ANN system developed to monitor M. bovis cultures in vaccine production.
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Affiliation(s)
- Alejandra Bosch
- Centro de Investigación y Desarrollo en Fermentaciones Industriales CINDEFI, UNLP, CONICET La Plata, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina
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Systematic functional analysis reveals that a set of seven genes is involved in fine-tuning of the multiple functions mediated by type IV pili in Neisseria meningitidis. Infect Immun 2010; 78:3053-63. [PMID: 20439474 DOI: 10.1128/iai.00099-10] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type IV pili (Tfp), which mediate multiple phenotypes ranging from adhesion to motility, are one of the most widespread virulence factors in bacteria. However, the molecular mechanisms of Tfp biogenesis and associated functions remain poorly understood. One of the underlying reasons is that the roles played by the numerous genes involved in Tfp biology are unclear because corresponding mutants have been studied on a case-by-case basis, in different species, and using different assays, often generating heterogeneous results. Therefore, we have recently started a systematic functional analysis of the genes involved in Tfp biology in a well-characterized clinical isolate of the human pathogen Neisseria meningitidis. After previously studying 16 genes involved in Tfp biogenesis, here we report the characterization of 7 genes that are dispensable for piliation and potentially involved in Tfp biology. Using a battery of assays, we assessed piliation and each of the Tfp-linked functions in single mutants, double mutants in which filament retraction is abolished by a concurrent mutation in pilT, and strains overexpressing the corresponding proteins. This showed that each of the seven genes actually fine-tunes a Tfp-linked function(s), which brings us one step closer to a global view of Tfp biology in the meningococcus.
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Holz C, Opitz D, Greune L, Kurre R, Koomey M, Schmidt MA, Maier B. Multiple pilus motors cooperate for persistent bacterial movement in two dimensions. PHYSICAL REVIEW LETTERS 2010; 104:178104. [PMID: 20482147 DOI: 10.1103/physrevlett.104.178104] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Indexed: 05/29/2023]
Abstract
In various bacterial species surface motility is mediated by cycles of type IV pilus motor elongation, adhesion, and retraction, but it is unclear whether bacterial movement follows a random walk. Here we show that the correlation time of persistent movement in Neisseria gonorrhoeae increases with the number of pili. The unbinding force of individual pili from the surface F=10 pN was considerably lower than the stalling force F>100 pN, suggesting that density, force, and adhesive properties of the pilus motor enable a tug-of-war mechanism for bacterial movement.
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Affiliation(s)
- Claudia Holz
- Institut für Molekulare Zellbiologie, Schlossplatz 5, Westfälische Wilhelms-Universität Münster, Germany
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14
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Salomonsson E, Forsberg Å, Roos N, Holz C, Maier B, Koomey M, Winther-Larsen HC. Functional analyses of pilin-like proteins from Francisella tularensis: complementation of type IV pilus phenotypes in Neisseria gonorrhoeae. Microbiology (Reading) 2009; 155:2546-2559. [DOI: 10.1099/mic.0.028183-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Accumulating evidence from a number of studies strongly suggests that proteins orthologous to those involved in type IV pili (Tfp) assembly and function are required for Francisella pathogenicity. However, the molecular mechanisms by which the components exert their influence on virulence remain poorly understood. Owing to the conservation and promiscuity of Tfp biogenesis machineries, expression of Tfp pilins in heterologous species has been used successfully to analyse organelle structure–function relationships. In this study we expressed a number of Francisella pilin genes in the Tfp-expressing pathogen Neisseria gonorrhoeae lacking its endogenous pilin subunit. Two gene products, the orthologous PilA proteins from Francisella tularensis subspecies tularensis and novicida, were capable of restoring the expression of Tfp-like appendages that were shown to be dependent upon the neisserial Tfp biogenesis machinery for surface localization. Expression of Francisella PilA pilins also partially restored competence for natural transformation in N. gonorrhoeae. This phenotype was not complemented by expression of the PulG and XcpT proteins, which are equivalent components of the related type II protein secretion system. Taken together, these findings provide compelling, although indirect, evidence of the potential for Francisella PilA proteins to express functional Tfp.
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Affiliation(s)
- Emelie Salomonsson
- Umeå Centre for Microbial Research (UCMR) and Laboratory for Molecular Infection Medicine, Sweden (MIMS), Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
- CBRN Defence and Security, FOI Swedish Defence Research Agency, Cementvägen 20, 901 82 Umeå, Sweden
| | - Åke Forsberg
- Umeå Centre for Microbial Research (UCMR) and Laboratory for Molecular Infection Medicine, Sweden (MIMS), Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
- CBRN Defence and Security, FOI Swedish Defence Research Agency, Cementvägen 20, 901 82 Umeå, Sweden
| | - Norbert Roos
- Department of Molecular Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Claudia Holz
- Westfälische Wilhelms-Universität Münster, Institut für Allgemeine Zoologie und Genetik, 48149 Münster, Germany
| | - Berenike Maier
- Westfälische Wilhelms-Universität Münster, Institut für Allgemeine Zoologie und Genetik, 48149 Münster, Germany
| | - Michael Koomey
- Centre for Molecular Biology and Neuroscience, University of Oslo, 0316 Oslo, Norway
- Department of Molecular Biosciences, University of Oslo, 0316 Oslo, Norway
| | - Hanne C. Winther-Larsen
- Centre for Molecular Biology and Neuroscience, University of Oslo, 0316 Oslo, Norway
- Department of Molecular Biosciences, University of Oslo, 0316 Oslo, Norway
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15
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Dietrich M, Mollenkopf H, So M, Friedrich A. Pilin regulation in the pilT mutant of Neisseria gonorrhoeae strain MS11. FEMS Microbiol Lett 2009; 296:248-56. [PMID: 19486161 DOI: 10.1111/j.1574-6968.2009.01647.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The ATPase protein PilT mediates retraction of type IV pili (Tfp). Tfp retraction of Neisseria gonorrhoeae causes many signal transduction events and changes in gene expression in infected epithelial cells. To find out whether a pilT mutation and lack of Tfp retraction, respectively, lead also to gene regulation in bacteria, we performed microarrays comparing the transcriptional profiles of the N. gonorrhoeae parent strain MS11 and its isogenic pilT mutant during growth in vitro. A loss-of-function-mutation in pilT led to altered transcript levels of 63 ORFs. Levels of pilE transcripts and its deduced protein, the major Tfp subunit pilin, were increased most markedly by a mutation in pilT. Further studies revealed that pilE expression was also controlled by two other genes encoding Tfp biogenesis proteins, pilD and pilF. Our studies strongly suggest that pilE expression is a finely tuned process.
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Affiliation(s)
- Manuela Dietrich
- Department of Molecular Biology, Max Planck Institute for Infection Biology, Berlin, Germany
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16
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Helm RA, Barnhart MM, Seifert HS. pilQ Missense mutations have diverse effects on PilQ multimer formation, piliation, and pilus function in Neisseria gonorrhoeae. J Bacteriol 2007; 189:3198-207. [PMID: 17277065 PMCID: PMC1855849 DOI: 10.1128/jb.01833-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Type IV pili are required for virulence in Neisseria gonorrhoeae, as they are involved in adherence to host epithelium, twitching motility, and DNA transformation. The outer membrane secretin PilQ forms a homododecameric ring through which the pilus is proposed to be secreted. pilQ null mutants are nonpiliated, and thus, all pilus-dependent functions are eliminated. Mutagenesis was performed on the middle one-third of pilQ, and mutants with colony morphologies consistent with the colony morphology of nonpiliated or underpiliated bacteria were selected. Nineteen mutants, each with a single amino acid substitution, were isolated and displayed diverse phenotypes in terms of PilQ multimer stability, pilus expression, transformation efficiency, and host cell adherence. The 19 mutants were grouped into five phenotypic classes based on functionality. Four of the five mutant classes fit the current model of pilus functionality, which proposes that a functional pilus assembly apparatus, not necessarily full-length pili, is required for transformation, while high levels of displayed pili are required for adherence. One class, despite having an underpiliated colony morphology, expressed high levels of pili yet adhered poorly, demonstrating that pilus expression is necessary but not sufficient for adherence and indicating that PilQ may be directly involved in host cell adherence. The collection of phenotypes expressed by these mutants suggests that PilQ has an active role in pilus expression and function.
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Affiliation(s)
- R Allen Helm
- Department of Microbiology-Immunology, Northwestern University's Feinberg School of Medicine, S213, 303 East Chicago Avenue, Chicago, IL 60611, USA
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17
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Zhao S, Tobiason DM, Hu M, Seifert HS, Nicholas RA. The penC mutation conferring antibiotic resistance in Neisseria gonorrhoeae arises from a mutation in the PilQ secretin that interferes with multimer stability. Mol Microbiol 2005; 57:1238-51. [PMID: 16101998 PMCID: PMC2673695 DOI: 10.1111/j.1365-2958.2005.04752.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The penC resistance gene was previously characterized in an FA19 penA mtrR penB gonococcal strain (PR100) as a spontaneous mutation that increased resistance to penicillin and tetracycline. We show here that antibiotic resistance mediated by penC is the result of a Glu-666 to Lys missense mutation in the pilQ gene that interferes with the formation of the SDS-resistant high-molecular-mass PilQ secretin complex, disrupts piliation and decreases transformation frequency by 50-fold. Deletion of pilQ in PR100 confers the same level of antibiotic resistance as the penC mutation, but increased resistance was observed only in strains containing the mtrR and penB resistance determinants. Site-saturation mutagenesis of Glu-666 revealed that only acidic or amidated amino acids at this position preserved PilQ function. Consistent with early studies suggesting the importance of cysteine residues for stability of the PilQ multimer, mutation of either of the two cysteine residues in FA19 PilQ led to a similar phenotype as penC: increased antibiotic resistance, loss of piliation, intermediate levels of transformation competence and absence of SDS-resistant PilQ oligomers. These data show that a functional secretin complex can enhance the entry of antibiotics into the cell and suggest that the PilQ oligomer forms a pore in the outer membrane through which antibiotics diffuse into the periplasm.
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Affiliation(s)
- Shuqing Zhao
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
| | - Deborah M. Tobiason
- Department of Microbiology and Immunology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | | | - H. Steven Seifert
- Department of Microbiology and Immunology, Northwestern University's Feinberg School of Medicine, Chicago, Illinois 60611, USA
| | - Robert A. Nicholas
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC USA
- To whom correspondence should be addressed at: University of North Carolina at Chapel Hill Department of Pharmacology CB#7365 Chapel Hill, NC 27599-7365 Office: (919) 966-6547 Fax: (919) 966-5640
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18
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Winther-Larsen HC, Wolfgang M, Dunham S, van Putten JPM, Dorward D, Løvold C, Aas FE, Koomey M. A conserved set of pilin-like molecules controls type IV pilus dynamics and organelle-associated functions in Neisseria gonorrhoeae. Mol Microbiol 2005; 56:903-17. [PMID: 15853879 DOI: 10.1111/j.1365-2958.2005.04591.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Type IV pili (Tfp) play central roles in prokaryotic cell biology and disease pathogenesis. As dynamic filamentous polymers, they undergo rounds of extension and retraction modelled as pilin subunit polymerization and depolymerization events. Currently, the molecular mechanisms and components influencing Tfp dynamics remain poorly understood. Using Neisseria gonorrhoeae as a model system, we show that mutants lacking any one of a set of five proteins sharing structural similarity to the pilus subunit are dramatically reduced in Tfp expression and that these defects are suppressed in the absence of the PilT pilus retraction protein. Thus, these molecules are not canonical assembly factors but rather act as effectors of pilus homeostasis by promoting extension/polymerization events in the presence of PilT. Furthermore, localization studies support the conclusion that these molecules form a Tfp-associated complex and influence levels of PilC, the epithelial cell adhesin, in Tfp-enriched shear fractions. This is the first time that the step at which individual pilin-like proteins impact on Tfp expression has been defined. The findings have important implications for understanding Tfp dynamics and fundamental Tfp structure/function relationships.
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19
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Morand PC, Bille E, Morelle S, Eugène E, Beretti JL, Wolfgang M, Meyer TF, Koomey M, Nassif X. Type IV pilus retraction in pathogenic Neisseria is regulated by the PilC proteins. EMBO J 2004; 23:2009-17. [PMID: 15103324 PMCID: PMC404320 DOI: 10.1038/sj.emboj.7600200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2003] [Accepted: 03/10/2004] [Indexed: 02/07/2023] Open
Abstract
Pathogenic Neisseria express type IV pili (tfp), which have been shown to play a central role in the interactions of bacteria with their environment. The regulation of piliation thus constitutes a central element in bacterial life cycle. The PilC proteins are outer membrane-associated proteins that have a key role in tfp biogenesis since PilC-null mutants appear defective for fibre expression. Moreover, tfp are also subjected to retraction, which is under the control of the PilT nucleotide-binding protein. In this work, we bring evidence that fibre retraction involves the translocation of pilin subunits to the cytoplasmic membrane. Furthermore, by engineering meningococcal strains that harbour inducible pilC genes, and with the use of meningococcus-cell interaction as a model for the sequential observation of fibre expression and retraction, we show that the PilC proteins regulate PilT-mediated fibre retraction.
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Affiliation(s)
- Philippe C Morand
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Paris, France
- Abteilung Molekulare Biologie, Max-Planck-Institut für Infektionsbiologie, Berlin, Germany
| | - Emmanuelle Bille
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Paris, France
| | - Sandrine Morelle
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Paris, France
| | - Emmanuel Eugène
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Paris, France
| | - Jean-Luc Beretti
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Paris, France
| | - Matthew Wolfgang
- Department of Microbiology and Immunology and Cystic Fibrosis, Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, NC, USA
| | - Thomas F Meyer
- Abteilung Molekulare Biologie, Max-Planck-Institut für Infektionsbiologie, Berlin, Germany
| | - Michael Koomey
- Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway
| | - Xavier Nassif
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, Paris, France
- INSERM U570, Faculté de Médecine Necker-Enfants Malades, 156, rue de Vaugirard, 75015 Paris, France. Tel.: +33 1 4061 5379; Fax: +33 1 4061 5592; E-mail:
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20
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Long CD, Tobiason DM, Lazio MP, Kline KA, Seifert HS. Low-level pilin expression allows for substantial DNA transformation competence in Neisseria gonorrhoeae. Infect Immun 2003; 71:6279-91. [PMID: 14573647 PMCID: PMC219589 DOI: 10.1128/iai.71.11.6279-6291.2003] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gonococcal pilus is a major virulence factor that has well-established roles in mediating epithelial cell adherence and DNA transformation. Gonococci expressing four gonococcal pilin variants with distinct piliation properties under control of the lac regulatory system were grown in different levels of the inducer isopropyl-beta-D-thiogalactopyranoside (IPTG). These pilin variants expressed various levels of pilin message and pilin protein in response to the level of IPTG in the growth medium. Moreover, posttranslational modifications of the variant pilin proteins were detected, including S-pilin production and glycosylation. The ratio of the modified and unmodified pilin forms did not substantially change with different levels of pilin expression, showing that these modifications are not linked to pilin expression levels. DNA transformation competence was also influenced by IPTG levels in the growth medium. Substantial increases in transformation competence over an isogenic, nonpiliated mutant were observed when limited amounts of three of the pilin variants were expressed. Immunoelectron microscopy showed that when limited amounts of pilin are expressed, pili are rare and do not explain the pilin-dependent transformation competence. This pilin-dependent transformation competence required prepilin processing, the outer membrane secretin PilQ, and the twitching-motility-regulating protein PilT. These requirements show that a fully functional pilus assembly apparatus is required for DNA uptake when limited pilin is produced. We conclude that the pilus assembly apparatus functions to import DNA into the bacterial cell in a pilin-dependent manner but that extended pili are not required for transformation competence.
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Affiliation(s)
- Cynthia D Long
- Department of Microbiology-Immunology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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21
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Dieckelmann M, Roddam LF, Jennings MP. Purification of post-translationally modified proteins from bacteria: homologous expression and purification of histidine-tagged pilin from Neisseria meningitidis. Protein Expr Purif 2003; 30:69-77. [PMID: 12821323 DOI: 10.1016/s1046-5928(03)00061-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Until recently, glycosylation of proteins in prokaryotes was regarded as uncommon and thought to be limited to special cases such as S-layer proteins and some archeal outer membrane proteins. Now, there are an increasing number of reports of bacterial proteins that are glycosylated. Pilin of pathogenic Neisseria is one of the best characterised post-translationally modified bacterial proteins, with four different types of modifications reported, including a novel glycosylation. Pilin monomers assemble to form pilus fibres, which are long protein filaments that protrude from the surface of bacterial cells and are key virulence factors. To aid in the investigation of these modifications, pure pilin is required. A number of pilin purification methods have been published, but none are appropriate for the routine purification of pilin from many different isolates. This study describes a novel, rapid, and simple method of pilin purification from Neisseria meningitidis C311#3, which facilitates the production of consistent quantities of pure, native pilin. A 6x histidine tag was fused to the C-terminus of the pilin subunit structural gene, pilE, via homologous recombination placing the 6x histidine-tagged allele in the chromosome of N. meningitidis C311#3. Pilin was purified under non-denaturing conditions via a two-step process using immobilised metal affinity chromatography (IMAC), followed by dye affinity chromatography. Analysis of the purified pilin confirmed that it retained both of the post-translational modifications examined. This novel approach may prove to be a generally applicable method for purification and analysis of post-translationally modified proteins in bacteria.
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Affiliation(s)
- Manuela Dieckelmann
- Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, University of Queensland, St. Lucia, Qld. 4072, Australia
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22
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Maier B, Potter L, So M, Long CD, Seifert HS, Sheetz MP. Single pilus motor forces exceed 100 pN. Proc Natl Acad Sci U S A 2002; 99:16012-7. [PMID: 12446837 PMCID: PMC138556 DOI: 10.1073/pnas.242523299] [Citation(s) in RCA: 306] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2002] [Indexed: 11/18/2022] Open
Abstract
Force production by type IV pilus retraction is critical for infectivity of Neisseria gonorrhoeae and DNA transfer. We investigated the roles of pilus number and the retraction motor, PilT, in force generation in vivo at the single-molecule level and found that individual retraction events are generated by a single pilus fiber, and only one PilT complex powers retraction. Retraction velocity is constant at low forces but decreases at forces greater than 40 pN, giving a remarkably high average stall force of 110 +/- 30 pN. Further insights into the molecular mechanism of force generation are gained from the effect of ATP-depletion, which reduces the rate of retraction but not the stall force. Energetic considerations suggest that more than one ATP is involved in the removal of a single pilin subunit from a pilus. The results are most consistent with a model in which the ATPase PilT forms an oligomer that disassembles the pilus by a cooperative conformational change.
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Affiliation(s)
- Berenike Maier
- Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA
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23
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Skaar EP, Tobiason DM, Quick J, Judd RC, Weissbach H, Etienne F, Brot N, Seifert HS. The outer membrane localization of the Neisseria gonorrhoeae MsrA/B is involved in survival against reactive oxygen species. Proc Natl Acad Sci U S A 2002; 99:10108-13. [PMID: 12096194 PMCID: PMC126632 DOI: 10.1073/pnas.152334799] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2002] [Indexed: 11/18/2022] Open
Abstract
The PilB protein of Neisseria gonorrhoeae has been reported to be involved in the regulation of pilin gene transcription, but it also possesses significant homology to the peptide methionine sulfoxide reductase family of enzymes, specifically MsrA and MsrB from Escherichia coli. MsrA and MsrB in E. coli are able to reduce methionine sulfoxide residues in proteins to methionines. In addition, the gonococcal PilB protein encodes for both MsrA and MsrB activity associated with the repair of oxidative damage to proteins. In this work, we demonstrate that the PilB protein of Neisseria gonorrhoeae is not involved in pilus expression. Additionally, we show that wild-type N. gonorrhoeae produces two forms of this polypeptide, one of which contains a signal sequence and is secreted from the bacterial cytoplasm to the outer membrane; the other lacks a signal sequence and is cytoplasmic. Furthermore, we show that the secreted form of the PilB protein is involved in survival in the presence of oxidative damage.
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Affiliation(s)
- Eric P Skaar
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, 303 East Chicago Avenue, Searle 6-497, Chicago, IL 60611, USA
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