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Sokolova D, Smolarska A, Bartnik P, Rabalski L, Kosinski M, Narajczyk M, Krzyżanowska DM, Rajewska M, Mruk I, Czaplewska P, Jafra S, Czajkowski R. Spontaneous mutations in hlyD and tuf genes result in resistance of Dickeya solani IPO 2222 to phage ϕD5 but cause decreased bacterial fitness and virulence in planta. Sci Rep 2023; 13:7534. [PMID: 37160956 PMCID: PMC10169776 DOI: 10.1038/s41598-023-34803-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/07/2023] [Indexed: 05/11/2023] Open
Abstract
Lytic bacteriophages able to infect and kill Dickeya spp. can be readily isolated from virtually all Dickeya spp. containing environments, yet little is known about the selective pressure those viruses exert on their hosts. Two spontaneous D. solani IPO 2222 mutants (0.8% of all obtained mutants), DsR34 and DsR207, resistant to infection caused by lytic phage vB_Dsol_D5 (ΦD5) were identified in this study that expressed a reduced ability to macerate potato tuber tissues compared to the wild-type, phage-susceptible D. solani IPO 2222 strain. Genome sequencing revealed that genes encoding: secretion protein HlyD (in mutant DsR34) and elongation factor Tu (EF-Tu) (in mutant DsR207) were altered in these strains. These mutations impacted the DsR34 and DsR207 proteomes. Features essential for the ecological success of these mutants in a plant environment, including their ability to use various carbon and nitrogen sources, production of plant cell wall degrading enzymes, ability to form biofilms, siderophore production, swimming and swarming motility and virulence in planta were assessed. Compared to the wild-type strain, D. solani IPO 2222, mutants DsR34 and DsR207 had a reduced ability to macerate chicory leaves and to colonize and cause symptoms in growing potato plants.
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Affiliation(s)
- Daryna Sokolova
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama 58, 80-307, Gdansk, Poland
- Department of Biophysics and Radiobiology, Institute of Cell Biology and Genetic Engineering, National Academy of Sciences of Ukraine, 148 Academika Zabolotnoho St., Kyiv, 03143, Ukraine
| | - Anna Smolarska
- Department of Cancer Biology, Institute of Biology, Warsaw, University of Life Sciences (SGGW), J. Ciszewskiego 8, 02-786, Warsaw, Poland
| | - Przemysław Bartnik
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama 58, 80-307, Gdansk, Poland
| | - Lukasz Rabalski
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama 58, 80-307, Gdansk, Poland
| | - Maciej Kosinski
- Laboratory of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama 58, 80-307, Gdansk, Poland
| | - Magdalena Narajczyk
- Laboratory of Electron Microscopy, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland
| | - Dorota M Krzyżanowska
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama 58, 80-307, Gdansk, Poland
| | - Magdalena Rajewska
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama, 58, 80-307, Gdansk, Poland
| | - Inez Mruk
- Laboratory of Mass Spectrometry-Core Facility Laboratories, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, Antoniego Abrahama 58, 80-307, Gdansk, Poland
| | - Paulina Czaplewska
- Laboratory of Mass Spectrometry-Core Facility Laboratories, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, Antoniego Abrahama 58, 80-307, Gdansk, Poland
| | - Sylwia Jafra
- Laboratory of Plant Microbiology, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama, 58, 80-307, Gdansk, Poland
| | - Robert Czajkowski
- Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology UG and MUG, University of Gdansk, A. Abrahama 58, 80-307, Gdansk, Poland.
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Scaffolding Protein GspB/OutB Facilitates Assembly of the Dickeya dadantii Type 2 Secretion System by Anchoring the Outer Membrane Secretin Pore to the Inner Membrane and to the Peptidoglycan Cell Wall. mBio 2022; 13:e0025322. [PMID: 35546537 PMCID: PMC9239104 DOI: 10.1128/mbio.00253-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The phytopathogenic proteobacterium Dickeya dadantii secretes an array of plant cell wall-degrading enzymes and other virulence factors via the type 2 secretion system (T2SS). T2SSs are widespread among important plant, animal, and human bacterial pathogens. This multiprotein complex spans the double membrane cell envelope and secretes fully folded proteins through a large outer membrane pore formed by 15 subunits of the secretin GspD. Secretins are also found in the type 3 secretion system and the type 4 pili. Usually, specialized lipoproteins termed pilotins assist the targeting and assembly of secretins into the outer membrane. Here, we show that in D. dadantii, the pilotin acts in concert with the scaffolding protein GspB. Deletion of gspB profoundly impacts secretin assembly, pectinase secretion, and virulence. Structural studies reveal that GspB possesses a conserved periplasmic homology region domain that interacts directly with the N-terminal secretin domain. Site-specific photo-cross-linking unravels molecular details of the GspB-GspD complex in vivo. We show that GspB facilitates outer membrane targeting and assembly of the secretin pores and anchors them to the inner membrane while the C-terminal extension of GspB provides a scaffold for the secretin channel in the peptidoglycan cell wall. Phylogenetic analysis shows that in other bacteria, GspB homologs vary in length and domain composition and act in concert with either a cognate ATPase GspA or the pilotin GspS.
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Wang G, Qing li, Tang W, Ma F, Wang H, Xu X, Qiu W. AprD is important for extracellular proteolytic activity, physicochemical properties and spoilage potential in meat-borne Pseudomonas fragi. Food Control 2021. [DOI: 10.1016/j.foodcont.2021.107868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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4
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Alav I, Kobylka J, Kuth MS, Pos KM, Picard M, Blair JMA, Bavro VN. Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria. Chem Rev 2021; 121:5479-5596. [PMID: 33909410 PMCID: PMC8277102 DOI: 10.1021/acs.chemrev.1c00055] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components-the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.
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Affiliation(s)
- Ilyas Alav
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jessica Kobylka
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Miriam S. Kuth
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Klaas M. Pos
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Martin Picard
- Laboratoire
de Biologie Physico-Chimique des Protéines Membranaires, CNRS
UMR 7099, Université de Paris, 75005 Paris, France
- Fondation
Edmond de Rothschild pour le développement de la recherche
Scientifique, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jessica M. A. Blair
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Vassiliy N. Bavro
- School
of Life Sciences, University of Essex, Colchester, CO4 3SQ United Kingdom
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5
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Secrete or perish: The role of secretion systems in Xanthomonas biology. Comput Struct Biotechnol J 2020; 19:279-302. [PMID: 33425257 PMCID: PMC7777525 DOI: 10.1016/j.csbj.2020.12.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/13/2020] [Accepted: 12/13/2020] [Indexed: 12/22/2022] Open
Abstract
Bacteria of the Xanthomonas genus are mainly phytopathogens of a large variety of crops of economic importance worldwide. Xanthomonas spp. rely on an arsenal of protein effectors, toxins and adhesins to adapt to the environment, compete with other microorganisms and colonize plant hosts, often causing disease. These protein effectors are mainly delivered to their targets by the action of bacterial secretion systems, dedicated multiprotein complexes that translocate proteins to the extracellular environment or directly into eukaryotic and prokaryotic cells. Type I to type VI secretion systems have been identified in Xanthomonas genomes. Recent studies have unravelled the diverse roles played by the distinct types of secretion systems in adaptation and virulence in xanthomonads, unveiling new aspects of their biology. In addition, genome sequence information from a wide range of Xanthomonas species and pathovars have become available recently, uncovering a heterogeneous distribution of the distinct families of secretion systems within the genus. In this review, we describe the architecture and mode of action of bacterial type I to type VI secretion systems and the distribution and functions associated with these important nanoweapons within the Xanthomonas genus.
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A CpxR-Regulated zapD Gene Involved in Biofilm Formation of Uropathogenic Proteus mirabilis. Infect Immun 2020; 88:IAI.00207-20. [PMID: 32284373 DOI: 10.1128/iai.00207-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 04/08/2020] [Indexed: 02/07/2023] Open
Abstract
Proteus mirabilis, a frequent uropathogen, forms extensive biofilms on catheters that are infamously difficult to treat. To explore the mechanisms of biofilm formation by P. mirabilis, we performed in vivo transposon mutagenesis. A mutant with impaired biofilm formation was isolated. The mutant was found to have Tn5 inserted in the zapD gene, encoding an outer membrane protein of the putative type 1 secretion system ZapBCD. zapBCD and its upstream zapA gene, encoding a protease, constitute an operon under the control of CpxR, a two-component regulator. The cpxR mutant and zapA mutant strains also had a biofilm-forming defect. CpxR positively regulates the promoter activities of zapABCD, cpxP, and cpxR An electrophoretic mobility shift assay revealed that CpxR binds zapA promoter DNA. The loss of zapD reduced CpxR-regulated gene expression of cpxR, zapA, cpxP, and mrpA, the mannose-resistant Proteus-like (MR/P) fimbrial major subunit gene. The restoration of biofilm formation in the zapD mutant with a CpxR-expressing plasmid reinforces the idea that CpxR-mediated gene expression contributes to zapD-involved biofilm formation. In trans expression of zapBCD from a zapBCD-expressing plasmid also reestablished the biofilm formation ability of the cpxR mutant to a certain level. The zapD and cpxR mutants had significantly lower protease activity, adhesion, and autoaggregation ability and production of exopolysaccharides and extracellular DNA (eDNA) than did the wild type. Finally, we identified copper as a signal for CpxR to increase biofilm formation. The loss of cpxR or zapD abolished the copper-mediated biofilm upshift. CpxR was required for copper-induced expression of zapA and cpxR Taken together, these data highlight the important role of CpxR-regulated zapD in biofilm formation and the underlying mechanisms in P. mirabilis.
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7
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Baumann U. Structure-Function Relationships of the Repeat Domains of RTX Toxins. Toxins (Basel) 2019; 11:toxins11110657. [PMID: 31718085 PMCID: PMC6891781 DOI: 10.3390/toxins11110657] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/07/2019] [Accepted: 11/09/2019] [Indexed: 01/08/2023] Open
Abstract
RTX proteins are a large family of polypeptides of mainly Gram-negative origin that are secreted into the extracellular medium by a type I secretion system featuring a non-cleavable C-terminal secretion signal, which is preceded by a variable number of nine-residue tandem repeats. The three-dimensional structure forms a parallel β-roll, where β-strands of two parallel sheets are connected by calcium-binding linkers in such a way that a right-handed spiral is built. The Ca2+ ions are an integral part of the structure, which cannot form without them. The structural determinants of this unique architecture will be reviewed with its conservations and variations together with the implication for secretion and folding of these proteins. The general purpose of the RTX domains appears to act as an internal chaperone that keeps the polypeptide unfolded in the calcium-deprived cytosol and triggers folding in the calcium-rich extracellular medium. A rather recent addition to the structural biology of the RTX toxin is a variant occurring in a large RTX adhesin, where this non-canonical β-roll binds to ice and diatoms.
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Affiliation(s)
- Ulrich Baumann
- Institute of Biochemistry, University of Cologne, Zülpicherstrasse 47, D-50674 Cologne, Germany
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8
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Holland IB. Rise and rise of the ABC transporter families. Res Microbiol 2019; 170:304-320. [PMID: 31442613 DOI: 10.1016/j.resmic.2019.08.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/30/2019] [Accepted: 08/13/2019] [Indexed: 01/15/2023]
Abstract
This review will inevitably be influenced by my personal experience and personal view of the progression of this amazing family of proteins. This has generated a huge literature in over nearly five decades, some ideas have bloomed and faded while others have persisted, other contributions simply become redundant, overtaken by better techniques. At the outset, the pioneers had no idea of the magnitude of the topic they were working on, then a very rough idea of the significance emerged and, progressively, the picture becomes sharper and finally extraordinary. I have tried to produce at least an outline of that progression. My apologies for the also inevitable omissions, especially relating to the mass of biochemical and spectroscopy and genetical studies. I decided to prioritise structural biology because structures when successful are definitive and of course provide a 'visual' image. However, I tried to limit the structural aspects to the proteins that reflected the main advances.
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Affiliation(s)
- I Barry Holland
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Sud, Orsay, France.
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9
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Learning the ABCs one at a time: structure and mechanism of ABC transporters. Biochem Soc Trans 2019; 47:23-36. [PMID: 30626703 DOI: 10.1042/bst20180147] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/16/2018] [Accepted: 11/29/2018] [Indexed: 12/21/2022]
Abstract
ATP-binding cassette (ABC) transporters are essential proteins that are found across all kingdoms of life. ABC transporters harness the energy of ATP hydrolysis to drive the import of nutrients inside bacterial cells or the export of toxic compounds or essential lipids across bacteria and eukaryotic membranes. Typically, ABC transporters consist of transmembrane domains (TMDs) and nucleotide-binding domains (NBDs) to bind their substrate and ATP, respectively. The TMDs dictate what ligands can be recognised, whereas the NBDs are the power engine of the ABC transporter, carrying out ATP binding and hydrolysis. It has been proposed that they utilise the alternating access mechanism, inward- to outward-facing conformation, to transport their substrates. Here, we will review the recent progress on the structure determination of eukaryotic and bacterial ABC transporters as well as the novel mechanisms that have also been proposed, that fall out of the alternating access mechanism model.
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10
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Dorati F, Barrett GA, Sanchez-Contreras M, Arseneault T, José MS, Studholme DJ, Murillo J, Caballero P, Waterfield NR, Arnold DL, Shaw LJ, Jackson RW. Coping with Environmental Eukaryotes; Identification of Pseudomonas syringae Genes during the Interaction with Alternative Hosts or Predators. Microorganisms 2018; 6:microorganisms6020032. [PMID: 29690522 PMCID: PMC6027264 DOI: 10.3390/microorganisms6020032] [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] [Received: 03/20/2018] [Revised: 04/09/2018] [Accepted: 04/20/2018] [Indexed: 12/13/2022] Open
Abstract
Understanding the molecular mechanisms underpinning the ecological success of plant pathogens is critical to develop strategies for controlling diseases and protecting crops. Recent observations have shown that plant pathogenic bacteria, particularly Pseudomonas, exist in a range of natural environments away from their natural plant host e.g., water courses, soil, non-host plants. This exposes them to a variety of eukaryotic predators such as nematodes, insects and amoebae present in the environment. Nematodes and amoeba in particular are bacterial predators while insect herbivores may act as indirect predators, ingesting bacteria on plant tissue. We therefore postulated that bacteria are probably under selective pressure to avoid or survive predation and have therefore developed appropriate coping mechanisms. We tested the hypothesis that plant pathogenic Pseudomonas syringae are able to cope with predation pressure and found that three pathovars show weak, but significant resistance or toxicity. To identify the gene systems that contribute to resistance or toxicity we applied a heterologous screening technique, called Rapid Virulence Annotation (RVA), for anti-predation and toxicity mechanisms. Three cosmid libraries for P. syringae pv. aesculi, pv. tomato and pv. phaseolicola, of approximately 2000 cosmids each, were screened in the susceptible/non-toxic bacterium Escherichia coli against nematode, amoebae and an insect. A number of potential conserved and unique genes were identified which included genes encoding haemolysins, biofilm formation, motility and adhesion. These data provide the first multi-pathovar comparative insight to how plant pathogens cope with different predation pressures and infection of an insect gut and provide a foundation for further study into the function of selected genes and their role in ecological success.
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Affiliation(s)
- Federico Dorati
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | - Glyn A Barrett
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | | | - Tanya Arseneault
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
- Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, Research and Development Centre, Quebec, J3B 3E6, Canada.
| | - Mateo San José
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
| | | | - Jesús Murillo
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, 31192 Mutilva, Spain.
| | - Primitivo Caballero
- Instituto de Agrobiotecnología, Universidad Pública de Navarra, 31192 Mutilva, Spain.
| | - Nicholas R Waterfield
- Department of Biology and Biochemistry, University of Bath, Bath, BA1 9BJ, UK.
- Warwick Medical School, University of Warwick, Warwick, CV4 7AL, UK.
| | - Dawn L Arnold
- Centre for Research in Bioscience, Faculty of Health and Applied Sciences, University of the West of England, Bristol, BS16 1QY, UK.
| | - Liz J Shaw
- School of Archaeology, Geography and Environmental Science, University of Reading, Reading, RG6 6AX, UK.
| | - Robert W Jackson
- School of Biological Sciences, University of Reading, Reading, RG6 6UR, UK.
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11
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Kanonenberg K, Spitz O, Erenburg IN, Beer T, Schmitt L. Type I secretion system—it takes three and a substrate. FEMS Microbiol Lett 2018; 365:4966979. [DOI: 10.1093/femsle/fny094] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/09/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Kerstin Kanonenberg
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Olivia Spitz
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Isabelle N Erenburg
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Tobias Beer
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
| | - Lutz Schmitt
- Institute of Biochemistry, Heinrich Heine University, 40225 Düsseldorf, Germany
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12
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Murata D, Okano H, Angkawidjaja C, Akutsu M, Tanaka SI, Kitahara K, Yoshizawa T, Matsumura H, Kado Y, Mizohata E, Inoue T, Sano S, Koga Y, Kanaya S, Takano K. Structural Basis for the Serratia marcescens Lipase Secretion System: Crystal Structures of the Membrane Fusion Protein and Nucleotide-Binding Domain. Biochemistry 2017; 56:6281-6291. [PMID: 29094929 DOI: 10.1021/acs.biochem.7b00985] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Serratia marcescens secretes a lipase, LipA, through a type I secretion system (T1SS). The T1SS for LipA, the Lip system, is composed of an inner membrane ABC transporter with its nucleotide-binding domains (NBD), LipB, a membrane fusion protein, LipC, and an outer membrane channel protein, LipD. Passenger protein secreted by this system has been functionally and structurally characterized well, but relatively little information about the transporter complex is available. Here, we report the crystallographic studies of LipC without the membrane anchor region, LipC-, and the NBD of LipB (LipB-NBD). LipC- crystallographic analysis has led to the determination of the structure of the long α-helical and lipoyl domains, but not the area where it interacts with LipB, suggesting that the region is flexible without LipB. The long α-helical domain has three α-helices, which interacts with LipD in the periplasm. LipB-NBD has the common overall architecture and ATP hydrolysis activity of ABC transporter NBDs. Using the predicted models of full-length LipB and LipD, the overall structural insight into the Lip system is discussed.
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Affiliation(s)
- Daichi Murata
- Department of Biomolecular Chemistry, Kyoto Prefectural University , Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
| | - Hiroyuki Okano
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Clement Angkawidjaja
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Masato Akutsu
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt , Max-von-Laue-Straße, 60438 Frankfurt am Main, Germany
| | - Shun-Ichi Tanaka
- College of Life Sciences, Ritsumeikan University , Noji-Higashi, Kusatsu 525-8577, Japan
| | - Kenyu Kitahara
- Department of Biomolecular Chemistry, Kyoto Prefectural University , Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
| | - Takuya Yoshizawa
- College of Life Sciences, Ritsumeikan University , Noji-Higashi, Kusatsu 525-8577, Japan
| | - Hiroyoshi Matsumura
- College of Life Sciences, Ritsumeikan University , Noji-Higashi, Kusatsu 525-8577, Japan
| | - Yuji Kado
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Eiichi Mizohata
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Tsuyoshi Inoue
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Satoshi Sano
- Department of Biomolecular Chemistry, Kyoto Prefectural University , Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
| | - Yuichi Koga
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Shigenori Kanaya
- Graduate School of Engineering, Osaka University , Yamadaoka, Suita 565-0871, Japan
| | - Kazufumi Takano
- Department of Biomolecular Chemistry, Kyoto Prefectural University , Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
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13
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Type I Protein Secretion-Deceptively Simple yet with a Wide Range of Mechanistic Variability across the Family. EcoSal Plus 2017; 7. [PMID: 28084193 DOI: 10.1128/ecosalplus.esp-0019-2015] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A very large type I polypeptide begins to reel out from a ribosome; minutes later, the still unidentifiable polypeptide, largely lacking secondary structure, is now in some cases a thousand or more residues longer. Synthesis of the final hundred C-terminal residues commences. This includes the identity code, the secretion signal within the last 50 amino acids, designed to dock with a waiting ATP binding cassette (ABC) transporter. What happens next is the subject of this review, with the main, but not the only focus on hemolysin HlyA, an RTX protein toxin secreted by the type I system. Transport substrates range from small peptides to giant proteins produced by many pathogens. These molecules, without detectable cellular chaperones, overcome enormous barriers, crossing two membranes before final folding on the cell surface, involving a unique autocatalytic process.Unfolded HlyA is extruded posttranslationally, C-terminal first. The transenvelope "tunnel" is formed by HlyB (ABC transporter), HlyD (membrane fusion protein) straddling the inner membrane and periplasm and TolC (outer membrane). We present a new evaluation of the C-terminal secretion code, and the structure function of HlyD and HlyB at the heart of this nanomachine. Surprisingly, key details of the secretion mechanism are remarkably variable in the many type I secretion system subtypes. These include alternative folding processes, an apparently distinctive secretion code for each type I subfamily, and alternative forms of the ABC transporter; most remarkably, the ABC protein probably transports peptides or polypeptides by quite different mechanisms. Finally, we suggest a putative structure for the Hly-translocon, HlyB, the multijointed HlyD, and the TolC exit.
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14
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Structure of a Type-1 Secretion System ABC Transporter. Structure 2017; 25:522-529. [PMID: 28216041 DOI: 10.1016/j.str.2017.01.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/13/2016] [Accepted: 01/29/2017] [Indexed: 02/07/2023]
Abstract
Type-1 secretion systems (T1SSs) represent a widespread mode of protein secretion across the cell envelope in Gram-negative bacteria. The T1SS is composed of an inner-membrane ABC transporter, a periplasmic membrane-fusion protein, and an outer-membrane porin. These three components assemble into a complex spanning both membranes and providing a conduit for the translocation of unfolded polypeptides. We show that ATP hydrolysis and assembly of the entire T1SS complex is necessary for protein secretion. Furthermore, we present a 3.15-Å crystal structure of AaPrtD, the ABC transporter found in the Aquifex aeolicus T1SS. The structure suggests a substrate entry window just above the transporter's nucleotide binding domains. In addition, highly kinked transmembrane helices, which frame a narrow channel not observed in canonical peptide transporters, are likely involved in substrate translocation. Overall, the AaPrtD structure supports a polypeptide transport mechanism distinct from alternating access.
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Eom GT, Oh JY, Park JH, Lim HJ, Lee SJ, Kim EY, Choi JE, Jegal J, Song BK, Yu JH, Song JK. Alleviation of temperature-sensitive secretion defect of Pseudomonas fluorescens ATP-binding cassette (ABC) transporter, TliDEF, by a change of single amino acid in the ABC protein, TliD. J Biosci Bioeng 2016; 122:283-6. [PMID: 27033673 DOI: 10.1016/j.jbiosc.2016.02.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 02/12/2016] [Accepted: 02/28/2016] [Indexed: 11/25/2022]
Abstract
An ABC transporter, TliDEF, from Pseudomonas fluorescens SIK W1, mediates the secretion of its cognate lipase, TliA, in a temperature-dependent secretion manner; the TliDEF-mediated secretion of TliA was impossible at the temperatures over 33°C. To isolate a mutant TliDEF capable of secreting TliA at 35°C, the mutagenesis of ABC protein (TliD) was performed. The mutated tliD library where a random point mutation was introduced by error-prone PCR was coexpressed with the wild-type tliE, tliF and tliA in Escherichia coli. Among approximately 10,000 colonies of the tliD library, we selected one colony that formed transparent halo on LB-tributyrin plates at 35°C. At the growth temperature of 35°C, the selected mutant TliD showed 1.75 U/ml of the extracellular lipase activity, while the wild-type TliDEF did not show any detectable lipase activity in the culture supernatant of E. coli. Moreover, the mutant TliD also showed higher level of TliA secretion than the wild-type TliDEF at other culture temperatures, 20°C, 25°C and 30°C. The mutant TliD had a single amino acid change (Ser287Pro) in the predicted transmembrane region in the membrane domain of TliD, implying that the corresponding region of TliD was important for causing the temperature-dependent secretion of TliDEF. These results suggested that the property of ABC transporter could be changed by the change of amino acid in the ABC protein.
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Affiliation(s)
- Gyeong Tae Eom
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea; Center for Industrial Chemical Biotechnology, Korea Research Institute of Chemical Technology (KRICT), 45 Jongga-ro, Jung-gu, Ulsan 681-802, Republic of Korea
| | - Joon Young Oh
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea
| | - Ji Hyun Park
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea
| | - Hye Jin Lim
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea; Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764, Republic of Korea
| | - So Jeong Lee
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea
| | - Eun Young Kim
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea
| | - Ji-Eun Choi
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea
| | - Jonggeon Jegal
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea; Center for Industrial Chemical Biotechnology, Korea Research Institute of Chemical Technology (KRICT), 45 Jongga-ro, Jung-gu, Ulsan 681-802, Republic of Korea
| | - Bong Keun Song
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea; Center for Industrial Chemical Biotechnology, Korea Research Institute of Chemical Technology (KRICT), 45 Jongga-ro, Jung-gu, Ulsan 681-802, Republic of Korea
| | - Ju-Hyun Yu
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea
| | - Jae Kwang Song
- Research Center for Bio-based Chemistry, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305-600, Republic of Korea; Department of Green Chemistry and Environmental Biotechnology, Korea University of Science and Technology (UST), 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350, Republic of Korea.
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Benz R. Channel formation by RTX-toxins of pathogenic bacteria: Basis of their biological activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:526-37. [PMID: 26523409 DOI: 10.1016/j.bbamem.2015.10.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/10/2015] [Accepted: 10/28/2015] [Indexed: 12/15/2022]
Abstract
The pore-forming cytolysins of the RTX-toxin (Repeats in ToXin) family are a relatively small fraction of a steadily increasing family of proteins that contain several functionally important glycine-rich and aspartate containing nonapeptide repeats. These cytolysins produced by a variety of Gram-negative bacteria form ion-permeable channels in erythrocytes and other eukaryotic cells. Hemolytic and cytolytic RTX-toxins represent pathogenicity factors of the toxin-producing bacteria and are very often important key factors in pathogenesis of the bacteria. Channel formation by RTX-toxins lead to the dissipation of ionic gradients and membrane potential across the cytoplasmic membrane of target cells, which results in cell death. Here we discuss channel formation and channel properties of some of the best known RTX-toxins, such as α-hemolysin (HlyA) of Escherichia coli and the uropathogenic EHEC strains, the adenylate cyclase toxin (ACT, CyaA) of Bordetella pertussis and the RTX-toxins (ApxI, ApxII and ApxIII) produced by different strains of Actinobacillus pleuropneumoniae. The channels formed by these RTX-toxins in lipid bilayers share some common properties such as cation selectivity and voltage-dependence. Furthermore the channels are transient and show frequent switching between different ion-conducting states. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Roland Benz
- Department of Life Sciences and Chemistry, Jacobs University, Campus Ring 1, 28759, Bremen, Germany.
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Delepelaire P, Izadi-Pruneyre N, Delepierre M, Ghigo JM, Schwartz M. A tribute to Cécile Wandersman. Res Microbiol 2015; 166:393-8. [PMID: 26258186 DOI: 10.1016/j.resmic.2015.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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18
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Functional type 1 secretion system involved in Legionella pneumophila virulence. J Bacteriol 2014; 197:563-71. [PMID: 25422301 DOI: 10.1128/jb.02164-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Legionella pneumophila is a Gram-negative pathogen found mainly in water, either in a free-living form or within infected protozoans, where it replicates. This bacterium can also infect humans by inhalation of contaminated aerosols, causing a severe form of pneumonia called legionellosis or Legionnaires' disease. The involvement of type II and IV secretion systems in the virulence of L. pneumophila is now well documented. Despite bioinformatic studies showing that a type I secretion system (T1SS) could be present in this pathogen, the functionality of this system based on the LssB, LssD, and TolC proteins has never been established. Here, we report the demonstration of the functionality of the T1SS, as well as its role in the infectious cycle of L. pneumophila. Using deletion mutants and fusion proteins, we demonstrated that the repeats-in-toxin protein RtxA is secreted through an LssB-LssD-TolC-dependent mechanism. Moreover, fluorescence monitoring and confocal microscopy showed that this T1SS is required for entry into the host cell, although it seems dispensable to the intracellular cycle. Together, these results underline the active participation of L. pneumophila, via its T1SS, in its internalization into host cells.
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Lam HN, Chakravarthy S, Wei HL, BuiNguyen H, Stodghill PV, Collmer A, Swingle BM, Cartinhour SW. Global analysis of the HrpL regulon in the plant pathogen Pseudomonas syringae pv. tomato DC3000 reveals new regulon members with diverse functions. PLoS One 2014; 9:e106115. [PMID: 25170934 PMCID: PMC4149516 DOI: 10.1371/journal.pone.0106115] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/28/2014] [Indexed: 11/18/2022] Open
Abstract
The type III secretion system (T3SS) is required for virulence in the gram-negative plant pathogen Pseudomonas syringae pv. tomato DC3000. The alternative sigma factor HrpL directly regulates expression of T3SS genes via a promoter sequence, often designated as the "hrp promoter." Although the HrpL regulon has been extensively investigated in DC3000, it is not known whether additional regulon members remain to be found. To systematically search for HrpL-regulated genes, we used chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) and bulk mRNA sequencing (RNA-Seq) to identify HrpL-binding sites and likely hrp promoters. The analysis recovered 73 sites of interest, including 20 sites that represent new hrp promoters. The new promoters lie upstream of a diverse set of genes encoding potential regulators, enzymes and hypothetical proteins. PSPTO_5633 is the only new HrpL regulon member that is potentially an effector and is now designated HopBM1. Deletions in several other new regulon members, including PSPTO_5633, PSPTO_0371, PSPTO_2130, PSPTO_2691, PSPTO_2696, PSPTO_3331, and PSPTO_5240, in either DC3000 or ΔhopQ1-1 backgrounds, do not affect the hypersensitive response or in planta growth of the resulting strains. Many new HrpL regulon members appear to be unrelated to the T3SS, and orthologs for some of these can be identified in numerous non-pathogenic bacteria. With the identification of 20 new hrp promoters, the list of HrpL regulon members is approaching saturation and most likely includes all DC3000 effectors.
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Affiliation(s)
- Hanh N. Lam
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Suma Chakravarthy
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Hai-Lei Wei
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - HoangChuong BuiNguyen
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Paul V. Stodghill
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Alan Collmer
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
| | - Bryan M. Swingle
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
| | - Samuel W. Cartinhour
- Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, New York, United States of America
- United States Department of Agriculture-Agricultural Research Service, Ithaca, New York, United States of America
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Pel MJC, van Dijken AJH, Bardoel BW, Seidl MF, van der Ent S, van Strijp JAG, Pieterse CMJ. Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:603-10. [PMID: 24654978 DOI: 10.1094/mpmi-02-14-0032-r] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant pathogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantly less virulent on both tomato and Arabidopsis thaliana. Moreover, infiltration of A. thaliana Col-0 leaves with DC3000 ΔaprA evoked a significantly higher level of expression of the defense-related genes FRK1 and PR-1 than did wild-type DC3000. In the flagellin receptor mutant fls2, pathogen virulence and defense-related gene activation did not differ between DC3000 and DC3000 ΔaprA. Together, these results suggest that AprA of DC3000 is important for evasion of recognition by the FLS2 receptor, allowing wild-type DC3000 to be more virulent on its host plant than AprA-deficient DC3000 ΔaprA. To provide further evidence for the role of DC3000 AprA in host immune evasion, we overexpressed the AprA inhibitory peptide AprI of DC3000 in A. thaliana to counteract the immune evasive capacity of DC3000 AprA. Ectopic expression of aprI in A. thaliana resulted in an enhanced level of resistance against wild-type DC3000, while the already elevated level of resistance against DC3000 ΔaprA remained unchanged. Together, these results indicate that evasion of host immunity by the alkaline protease AprA is important for full virulence of strain DC3000 and likely acts by preventing flagellin monomers from being recognized by its cognate immune receptor.
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Eom GT, Lee SH, Oh YH, Choi JE, Park SJ, Song JK. Efficient extracellular production of type I secretion pathway-dependent Pseudomonas fluorescens lipase in recombinant Escherichia coli by heterologous ABC protein exporters. Biotechnol Lett 2014; 36:2037-42. [DOI: 10.1007/s10529-014-1567-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/23/2014] [Indexed: 11/28/2022]
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Reverchon S, Nasser W. Dickeya ecology, environment sensing and regulation of virulence programme. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:622-36. [PMID: 24115612 DOI: 10.1111/1758-2229.12073] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 05/25/2013] [Accepted: 05/27/2013] [Indexed: 05/05/2023]
Abstract
The pectinolytic Dickeya spp. are soft-rot Gram-negative bacteria that cause severe disease in a wide range of plant species. In recent years, there has been an increase in the damage caused by Dickeya in potato crops in Europe. Soft-rot symptoms are due to the production and secretion of degradative enzymes that destroy the plant cell wall. However, an efficient colonization of the host plant requires many additional bacterial factors, including elements in the early stages allowing for the adhesion and penetration of the bacteria in the plant and different elements in the intermediate stages, involved in the adaptation to the new growth conditions encountered in the host. Dickeya pathogenicity is clearly a multifactorial process, and successful infection by these bacteria requires a temporal coordination of survival and virulence gene expression. This involves the ancestral nucleoid-associated proteins, Fis and H-NS, and modifications of DNA topology, as well as various specific regulatory systems, including a new quorum-sensing pathway and regulators that sense the bacterial metabolic status or environmental stresses. This review presents new information concerning the ecology of Dickeya and the strategies used by this bacterium to coordinate its survival and virulence programmes during infection.
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Kanonenberg K, Schwarz CKW, Schmitt L. Type I secretion systems - a story of appendices. Res Microbiol 2013; 164:596-604. [PMID: 23541474 DOI: 10.1016/j.resmic.2013.03.011] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/13/2013] [Indexed: 12/28/2022]
Abstract
Secretion is an essential task for prokaryotic organisms to interact with their surrounding environment. In particular, the production of extracellular proteins and peptides is important for many aspects of an organism's survival and adaptation to its ecological niche. In Gram-negative bacteria, six different protein secretion systems have been identified so far, named Type I to Type VI; differing greatly in their composition and mechanism of action (Economou et al., 2006). The two membranes present in Gram-negative bacteria are negotiated either by one-step transport mechanisms (Type I and Type III), where the unfolded substrate is translocated directly into the extracellular space, without any periplasmic intermediates, or by two-step mechanisms (Type II and Type V), where the substrate is first transported into the periplasm to allow folding before a second transport step across the outer membrane occurs. Here we focus on Type I secretion systems and summarise our current knowledge of these one-step transport machineries with emphasis on the N-terminal extensions found in many Type I-specific ABC transporters. ABC transporters containing an N-terminal C39 peptidase domain cut off a leader peptide present in the substrate prior to secretion. The function of the second type of appendix, the C39 peptidase-like domain (CLD), is not yet completely understood. Recent results have shown that it is nonetheless essential for secretion and interacts specifically with the substrate of the transporter. The third group present does not contain any appendix. In light of this difference we compare the function of the appendix and the differences that might exist among the three families of T1SS.
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Affiliation(s)
- Kerstin Kanonenberg
- Institute of Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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Nasser W, Dorel C, Wawrzyniak J, Van Gijsegem F, Groleau MC, Déziel E, Reverchon S. Vfm a new quorum sensing system controls the virulence ofDickeya dadantii. Environ Microbiol 2012; 15:865-80. [DOI: 10.1111/1462-2920.12049] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 10/30/2012] [Accepted: 11/10/2012] [Indexed: 02/03/2023]
Affiliation(s)
- William Nasser
- UMR5240 CNRS/INSA/UCB; Université de Lyon; F-69003; INSA-Lyon; Villeurbanne; F-69621; France
| | - Corinne Dorel
- UMR5240 CNRS/INSA/UCB; Université de Lyon; F-69003; INSA-Lyon; Villeurbanne; F-69621; France
| | - Julien Wawrzyniak
- UMR5240 CNRS/INSA/UCB; Université de Lyon; F-69003; INSA-Lyon; Villeurbanne; F-69621; France
| | | | | | - Eric Déziel
- INRS-Institut Armand-Frappier; Laval; Québec; H7V 1B7; Canada
| | - Sylvie Reverchon
- UMR5240 CNRS/INSA/UCB; Université de Lyon; F-69003; INSA-Lyon; Villeurbanne; F-69621; France
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Lecher J, Schwarz CKW, Stoldt M, Smits SHJ, Willbold D, Schmitt L. An RTX transporter tethers its unfolded substrate during secretion via a unique N-terminal domain. Structure 2012; 20:1778-87. [PMID: 22959622 DOI: 10.1016/j.str.2012.08.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/08/2012] [Accepted: 08/09/2012] [Indexed: 12/28/2022]
Abstract
Type 1 secretion systems (T1SS) catalyze the one step protein transport across the membranes of Gram-negative bacteria and are composed of an outer membrane protein, a membrane fusion protein and an ABC transporter. The ABC transporter consists of the canonical nucleotide binding and transmembrane domains. For the toxin hemolysin A (HlyA), the ABC transporter HlyB carries an additional, N-terminal domain sharing about 40% homology to C39 peptidases, but this "C39-like domain" (CLD) is suggested to feature another, yet unknown function. Our functional and structural analysis demonstrates that the CLD is essential for secretion and that it specifically interacts with the unfolded state of HlyA. We determined the nuclear magnetic resonance structure of the CLD as well as the substrate-binding region within the CLD. This mode of action, represents a mechanism within T1SS and answers the question, how a large and unfolded substrate is protected inside the cells during secretion.
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Affiliation(s)
- Justin Lecher
- Institute of Physical Biology, Heinrich-Heine-Universität, Universitätsstrasse 1, 40225 Düsseldorf, Germany
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Kraepiel Y, Pédron J, Patrit O, Simond-Côte E, Hermand V, Van Gijsegem F. Analysis of the plant bos1 mutant highlights necrosis as an efficient defence mechanism during D. dadantii/Arabidospis thaliana interaction. PLoS One 2011; 6:e18991. [PMID: 21533045 PMCID: PMC3080887 DOI: 10.1371/journal.pone.0018991] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 03/23/2011] [Indexed: 12/24/2022] Open
Abstract
Dickeya dadantii is a broad host range phytopathogenic bacterium provoking soft rot disease on many plants including Arabidopsis. We showed that, after D. dadantii infection, the expression of the Arabidopsis BOS1 gene was specifically induced by the production of the bacterial PelB/C pectinases able to degrade pectin. This prompted us to analyze the interaction between the bos1 mutant and D. dadantii. The phenotype of the infected bos1 mutant is complex. Indeed, maceration symptoms occurred more rapidly in the bos1 mutant than in the wild type parent but at a later stage of infection, a necrosis developed around the inoculation site that provoked a halt in the progression of the maceration. This necrosis became systemic and spread throughout the whole plant, a phenotype reminiscent of that observed in some lesion mimic mutants. In accordance with the progression of maceration symptoms, bacterial population began to grow more rapidly in the bos1 mutant than in the wild type plant but, when necrosis appeared in the bos1 mutant, a reduction in bacterial population was observed. From the plant side, this complex interaction between D. dadantii and its host includes an early plant defence response that comprises reactive oxygen species (ROS) production accompanied by the reinforcement of the plant cell wall by protein cross-linking. At later timepoints, another plant defence is raised by the death of the plant cells surrounding the inoculation site. This plant cell death appears to constitute an efficient defence mechanism induced by D. dadantii during Arabidopsis infection.
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Affiliation(s)
- Yvan Kraepiel
- INRA, UMR217, Interactions Plantes-Pathogènes, Paris, France
- UPMC Univ Paris 06, UMR217, Interactions Plantes-Pathogènes, Paris, France
- AgroParisTech, UMR217, Interactions Plantes-Pathogènes, Paris, France
| | - Jacques Pédron
- INRA, UMR217, Interactions Plantes-Pathogènes, Paris, France
- UPMC Univ Paris 06, UMR217, Interactions Plantes-Pathogènes, Paris, France
- AgroParisTech, UMR217, Interactions Plantes-Pathogènes, Paris, France
| | - Oriane Patrit
- INRA, UMR217, Interactions Plantes-Pathogènes, Paris, France
- UPMC Univ Paris 06, UMR217, Interactions Plantes-Pathogènes, Paris, France
- AgroParisTech, UMR217, Interactions Plantes-Pathogènes, Paris, France
| | - Elizabeth Simond-Côte
- INRA, UMR217, Interactions Plantes-Pathogènes, Paris, France
- UPMC Univ Paris 06, UMR217, Interactions Plantes-Pathogènes, Paris, France
- AgroParisTech, UMR217, Interactions Plantes-Pathogènes, Paris, France
| | - Victor Hermand
- INRA, UMR217, Interactions Plantes-Pathogènes, Paris, France
- UPMC Univ Paris 06, UMR217, Interactions Plantes-Pathogènes, Paris, France
- AgroParisTech, UMR217, Interactions Plantes-Pathogènes, Paris, France
| | - Frédérique Van Gijsegem
- INRA, UMR217, Interactions Plantes-Pathogènes, Paris, France
- UPMC Univ Paris 06, UMR217, Interactions Plantes-Pathogènes, Paris, France
- AgroParisTech, UMR217, Interactions Plantes-Pathogènes, Paris, France
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Linhartová I, Bumba L, Mašín J, Basler M, Osička R, Kamanová J, Procházková K, Adkins I, Hejnová-Holubová J, Sadílková L, Morová J, Sebo P. RTX proteins: a highly diverse family secreted by a common mechanism. FEMS Microbiol Rev 2011; 34:1076-112. [PMID: 20528947 PMCID: PMC3034196 DOI: 10.1111/j.1574-6976.2010.00231.x] [Citation(s) in RCA: 360] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Repeats-in-toxin (RTX) exoproteins of Gram-negative bacteria form a steadily growing family of proteins with diverse biological functions. Their common feature is the unique mode of export across the bacterial envelope via the type I secretion system and the characteristic, typically nonapeptide, glycine- and aspartate-rich repeats binding Ca2+ ions. In this review, we summarize the current state of knowledge on the organization of rtx loci and on the biological and biochemical activities of therein encoded proteins. Applying several types of bioinformatic screens on the steadily growing set of sequenced bacterial genomes, over 1000 RTX family members were detected, with the biological functions of most of them remaining to be characterized. Activities of the so far characterized RTX family members are then discussed and classified according to functional categories, ranging from the historically first characterized pore-forming RTX leukotoxins, through the large multifunctional enzymatic toxins, bacteriocins, nodulation proteins, surface layer proteins, up to secreted hydrolytic enzymes exhibiting metalloprotease or lipase activities of industrial interest.
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Affiliation(s)
- Irena Linhartová
- Institute of Microbiology AS CR v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Al-Karablieh N, Weingart H, Ullrich MS. The outer membrane protein TolC is required for phytoalexin resistance and virulence of the fire blight pathogen Erwinia amylovora. Microb Biotechnol 2009; 2:465-75. [PMID: 21255278 PMCID: PMC3815907 DOI: 10.1111/j.1751-7915.2009.00095.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/15/2009] [Accepted: 01/19/2009] [Indexed: 11/29/2022] Open
Abstract
Erwinia amylovora causes fire blight on several plant species such as apple and pear, which produce diverse phytoalexins as defence mechanisms. An evolutionary successful pathogen thus must develop resistance mechanisms towards these toxic compounds. The E. amylovora outer membrane protein, TolC, might mediate phytoalexin resistance through its interaction with the multidrug efflux pump, AcrAB. To prove this, a tolC mutant and an acrB/tolC double mutant were constructed. The minimal inhibitory concentrations of diverse antimicrobials and phytoalexins were determined for these mutants and compared with that of a previously generated acrB mutant. The tolC and arcB/tolC mutants were considerably more susceptible than the wild type but showed similar levels as the acrB mutant. The results clearly indicated that neither TolC nor AcrAB significantly interacted with other transport systems during the efflux of the tested toxic compounds. Survival and virulence assays on inoculated apple plants showed that pathogenicity and the ability of E. amylovora to colonize plant tissue were equally impaired by mutations of tolC and acrB/tolC. Our results allowed the conclusion that TolC plays an important role as a virulence and fitness factor of E. amylovora by mediating resistance towards phytoalexins through its exclusive interaction with AcrAB.
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Affiliation(s)
- Nehaya Al-Karablieh
- School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen, Germany
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29
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Identification and characterization of hemolysin-like proteins similar to RTX toxin in Pasteurella pneumotropica. J Bacteriol 2009; 191:3698-705. [PMID: 19363112 DOI: 10.1128/jb.01527-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pasteurella pneumotropica is an opportunistic pathogen that causes lethal pneumonia in immunodeficient rodents. The virulence factors of this bacterium remain unknown. In this study, we identified the genes encoding two RTX toxins, designated as pnxI and pnxII, from the genomic DNA of P. pneumotropica ATCC 35149 and characterized with respect to hemolysis. The pnxI operon was organized according to the manner in which the genes encoded the structural RTX toxin (pnxIA), the type I secretion systems (pnxIB and pnxID), and the unknown orf. The pnxII gene was involved only with the pnxIIA that coded for a structural RTX toxin. Both the structural RTX toxins of deduced PnxIA and PnxIIA were involved in seven of the RTX repeat and repeat-like sequences. By quantitative PCR analysis of the structural RTX toxin-encoding genes in P. pneumotropica ATCC 35149, the gene expression of pnxIA was found to have increased from the early log phase, while that of pnxIIA increased from the late log to the early stationary phase. As expressed in Escherichia coli, both the recombinant proteins of PnxIA and PnxIIA showed weak hemolytic activity in both sheep and murine erythrocytes. On the basis of the results of the Southern blotting analysis, the pnxIA gene was detected in 82% of the isolates, while the pnxIIA gene was detected in 39%. These results indicate that the products of both pnxIA and pnxIIA were putative associations of virulence factors in the rodent pathogen P. pneumotropica.
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Characterization of TolC efflux pump proteins from Pasteurella multocida. Antimicrob Agents Chemother 2008; 52:4166-71. [PMID: 18725450 DOI: 10.1128/aac.00245-08] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Two TolC homologs, PM0527 and PM1980, were identified for Pasteurella multocida. A pm0527 mutant displayed increased susceptibility to a range of chemicals, including rifampin (512-fold) and acridine orange (128-fold). A pm1980 mutant showed increased susceptibility to rifampin, ceftazidime, and vancomycin.
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Cosme AM, Becker A, Santos MR, Sharypova LA, Santos PM, Moreira LM. The outer membrane protein TolC from Sinorhizobium meliloti affects protein secretion, polysaccharide biosynthesis, antimicrobial resistance, and symbiosis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:947-57. [PMID: 18533835 DOI: 10.1094/mpmi-21-7-0947] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Sinorhizobium meliloti is capable of establishing a symbiotic nitrogen fixation relationship with Medicago sativa. During this process, it must cope with diverse environments and has evolved different types of transport systems that help its propagation in the plant roots. TolC protein family members are the outer-membrane components of several transport systems involved in the export of diverse molecules, playing an important role in bacterial survival. In this work, we have characterized the protein TolC from S. meliloti 2011. An insertional mutation in the tolC gene strongly affected the resistance phenotype to antimicrobial agents and induced higher susceptibility to osmotic and oxidative stresses. Immunodetection experiments and comparison of the extracellular proteins present in the supernatant of the wild-type versus tolC mutant strains showed that the calcium-binding protein ExpE1, the endoglycanase ExsH, and the product of open reading frame SMc04171, a putative hemolysin-type calcium-binding protein, are secreted by a TolC-dependent secretion system. In the absence of TolC, neither succinoglycan nor galactoglucan were detected in the culture supernatant. Moreover, S. meliloti tolC mutant induced a reduced number of nonfixing nitrogen nodules in M. sativa roots. Taken together, our results confirm the importance of TolC in protein secretion, exopolysaccharide biosynthesis, antimicrobials resistance, and symbiosis.
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A novel serralysin metalloprotease from Deinococcus radiodurans. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2008; 1784:1256-64. [PMID: 18590838 DOI: 10.1016/j.bbapap.2008.05.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 05/23/2008] [Accepted: 05/27/2008] [Indexed: 10/22/2022]
Abstract
A hypothetical protein (DR2310) from the radiation resistant organism Deinococcus radiodurans harbors highly conserved Zn+2-binding (HEXXH) domain and Met-turn (SVMSY), characteristic of the serralysin family of secreted metalloproteases from Gram negative bacteria. Deletion mutagenesis of DR2310 confirmed that the ORF is expressed in Deinococcus radiodurans as a secreted protease of 85 kDa. Biochemical analysis revealed DR2310 to be a Ca+2 and Zn+2-requiring metalloprotease. Unique features such as a long N-terminus, replacement of the highly conserved C-terminal glycine rich Ca+2-binding repeats with a single N-terminal aspartate rich eukaryotic thrombospondin type-3 Ca+2-binding repeat and absence of C-terminal secretion signals make it a novel member of serralysin family. This is the first report of a functional serralysin family metalloprotease from a Gram positive organism.
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Lebeau A, Reverchon S, Gaubert S, Kraepiel Y, Simond-Côte E, Nasser W, Van Gijsegem F. The GacA global regulator is required for the appropriate expression of Erwinia chrysanthemi 3937 pathogenicity genes during plant infection. Environ Microbiol 2008; 10:545-59. [DOI: 10.1111/j.1462-2920.2007.01473.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mattinen L, Nissinen R, Riipi T, Kalkkinen N, Pirhonen M. Host-extract induced changes in the secretome of the plant pathogenic bacterium
Pectobacterium atrosepticum. Proteomics 2007; 7:3527-37. [PMID: 17726675 DOI: 10.1002/pmic.200600759] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pectobacterium atrosepticum is a Gram-negative plant pathogenic bacterium that causes rotting in potato stems and tubers. The secreted proteins of this pathogen were analyzed with proteomics from culture supernatant of cells grown in minimal medium supplemented with host extracts. More than 40 proteins were identified, among them known virulence determinants, such as pectic enzymes, metalloprotease, and virulence protein Svx, along with flagella proteins, GroEL and cyclophilin-type chaperones and several hypothetical proteins or proteins with unknown function. Some of the identified proteins may be involved in utilization of nutrients or transport of minerals. Northern and real-time RT-PCR analyses suggested that most of the proteins upregulated by plant extract were transcriptionally regulated. Among the identified proteins were VgrG and four homologs of hemolysin-coregulated proteins (Hcps). A mutant strain lacking one of the hcp genes was not affected in virulence, while a bacterial strain overexpressing the same gene was shown to have increased virulence, which suggests that these proteins may be new virulence determinants of P. atrosepticum. Comparison of the secretomes of wild type cells and hrcC mutant defective in Type III secretion suggested that the production of the identified proteins was independent of functional Type III secretion system.
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Affiliation(s)
- Laura Mattinen
- Department of Applied Biology, University of Helsinki, Finland
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35
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Posadas DM, Martín FA, Sabio y García JV, Spera JM, Delpino MV, Baldi P, Campos E, Cravero SL, Zorreguieta A. The TolC homologue of Brucella suis is involved in resistance to antimicrobial compounds and virulence. Infect Immun 2006; 75:379-89. [PMID: 17088356 PMCID: PMC1828412 DOI: 10.1128/iai.01349-06] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Brucella spp., like other pathogens, must cope with the environment of diverse host niches during the infection process. In doing this, pathogens evolved different type of transport systems to help them survive and disseminate within the host. Members of the TolC family have been shown to be involved in the export of chemically diverse molecules ranging from large protein toxins to small toxic compounds. The role of proteins from the TolC family in Brucella and other alpha-2-proteobacteria has been explored little. The gene encoding the unique member of the TolC family from Brucella suis (BepC) was cloned and expressed in an Escherichia coli mutant disrupted in the gene encoding TolC, which has the peculiarity of being involved in diverse transport functions. BepC fully complemented the resistance to drugs such as chloramphenicol and acriflavine but was incapable of restoring hemolysin secretion in the tolC mutant of E. coli. An insertional mutation in the bepC gene strongly affected the resistance phenotype of B. suis to bile salts and toxic chemicals such as ethidium bromide and rhodamine and significantly decreased the resistance to antibiotics such as erythromycin, ampicillin, tetracycline, and norfloxacin. Moreover, the B. suis bepC mutant was attenuated in the mouse model of infection. Taken together, these results suggest that BepC-dependent efflux processes of toxic compounds contribute to B. suis survival inside the host.
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Affiliation(s)
- Diana M Posadas
- Fundación Instituto Leloir, Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina
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36
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Song JK, Kim HS, Ahn HJ, Song BK, Rhee JS. Heterologous ABC exporter-based cloning of gram-negative bacterial type I secretion pathway-dependent metalloproteases from an Erwinia genomic DNA library in Escherichia coli. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2006.02.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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37
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Givskov M, Eberl L, Molin S. Control of exoenzyme production, motility and cell differentiation in Serratia liquefaciens. FEMS Microbiol Lett 2006. [DOI: 10.1111/j.1574-6968.1997.tb10276.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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38
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Omori K, Idei A. Gram-negative bacterial ATP-binding cassette protein exporter family and diverse secretory proteins. J Biosci Bioeng 2005; 95:1-12. [PMID: 16233359 DOI: 10.1016/s1389-1723(03)80141-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2002] [Accepted: 08/05/2002] [Indexed: 10/27/2022]
Abstract
Protein translocation to the extracellular space is essential for the invasion, colonization, and survival of pathogenic gram-negative bacteria within a host organism. In addition to the N-terminal signal sequence-dependent secretion system, which is specific for protein transport to the periplasmic space, there are five major systems (type I, II, III, IV, and V) that are known to be involved in protein secretion into the extracellular space. Of the systems, the type I pathway, which is composed of three membrane components including an ATP-binding cassette (ABC) protein, translocates proteins into the extracellular space from the cytosol by directly using the energy generated from ATP hydrolysis, and therefore, the system is a member of the ABC transporter family and is also known as the ABC exporter. To date, ABC exporters have been discovered to be involved in the secretion of a wide variety of exoproteins including RTX (repeats-in-toxin) toxins, cell surface layer proteins, proteases, lipases, bacteriocins, heme-acquisition proteins, and nodulation-related proteins such as the exoglucanases of gram-negative bacteria. A secretory protein and its associated specific ABC exporter are encoded in the same gene cluster in most cases, and ABC exporters show substrate specificity for secretion. Consequently, ABC exporters are present based primarily on the number of secretory protein genes. A secretion signal is situated in the C-terminal region of secretory proteins, however, the characteristics of the secretion signal are not fully understood. Secretory substrates and their linked ABC exporters are reviewed in the following paper.
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Affiliation(s)
- Kenji Omori
- Discovery Research Laboratory, Tanabe Seiyaku Co., Ltd., Kawagishi-2-chome, Toda, Saitama 335-8505, Japan.
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39
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Toporowski MC, Nomellini JF, Awram P, Levi A, Smit J. Transcriptional regulation of the S-layer protein type I secretion system inCaulobacter crescentus. FEMS Microbiol Lett 2005; 251:29-36. [PMID: 16111836 DOI: 10.1016/j.femsle.2005.07.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 07/18/2005] [Accepted: 07/19/2005] [Indexed: 10/25/2022] Open
Abstract
The Gram-negative Caulobacter crescentus exports RsaA, the crystalline S-layer subunit protein using a dedicated type I secretion system. The protein and two transporter genes (rsaADE) are located together, comparable to the Escherichia coli type I hemolysin hlyCABD operon, where read through of a stem loop following hlyCA results in reduced transcription of the hlyBD. Using two genetic approaches and a direct assessment of transcription from regions 5' to the genes we learned that rsaD and rsaE were transcribed together as a separate transcript from rsaA. These results are contrary to previous assumptions about the rsaADE type I secretion gene control and add another theme to the area of type I secretion transcription regulation. It may be that to accommodate the high levels of RsaA secretion, the type I transporters must be transcribed independently from rsaA.
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Affiliation(s)
- Michael C Toporowski
- University of British Columbia, Department of Microbiology and Immunology, Vancouver, B.C. Canada V6T 1Z3
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40
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Toporowski MC, Nomellini JF, Awram P, Smit J. Two outer membrane proteins are required for maximal type I secretion of the Caulobacter crescentus S-layer protein. J Bacteriol 2004; 186:8000-9. [PMID: 15547272 PMCID: PMC529074 DOI: 10.1128/jb.186.23.8000-8009.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Transport of RsaA, the crystalline S-layer subunit protein of Caulobacter crescentus, is mediated by a type I secretion mechanism. Two proteins have been identified that play the role of the outer membrane protein (OMP) component in the RsaA secretion machinery. The genes rsaF(a) and rsaF(b) were identified by similarity to the Escherichia coli hemolysin secretion OMP TolC by using the C. crescentus genome sequence. The rsaF(a) gene is located several kilobases downstream of the other transporter genes, while rsaF(b) is completely unlinked. An rsaF(a) knockout had approximately 56% secretion compared to wild-type levels, while the rsaF(b) knockout reduced secretion levels to approximately 79%. When expression of both proteins was eliminated, there was no RsaA secretion, but a residual level of approximately 9% remained inside the cell, suggesting posttranslational autoregulation. Complementation with either of the individual rsaF genes by use of a multicopy vector, which resulted in 8- to 10-fold overexpression of the proteins, did not restore RsaA secretion to wild-type levels, indicating that both rsaF genes were required for full-level secretion. However, overexpression of rsaF(a) (with normal rsaF(b) levels) in concert with overexpression of rsaA resulted in a 28% increase in RsaA secretion, indicating a potential for significantly increasing expression levels of an already highly expressing type I secretion system. This is the only known example of type I secretion requiring two OMPs to assemble a fully functional system.
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Affiliation(s)
- Michael C Toporowski
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3
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41
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Barabote RD, Johnson OL, Zetina E, San Francisco SK, Fralick JA, San Francisco MJD. Erwinia chrysanthemi tolC is involved in resistance to antimicrobial plant chemicals and is essential for phytopathogenesis. J Bacteriol 2003; 185:5772-8. [PMID: 13129948 PMCID: PMC193971 DOI: 10.1128/jb.185.19.5772-5778.2003] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2003] [Accepted: 07/17/2003] [Indexed: 11/20/2022] Open
Abstract
TolC is the outer-membrane component of several multidrug resistance (MDR) efflux pumps and plays an important role in the survival and virulence of many gram-negative bacterial animal pathogens. We have identified and characterized the outer-membrane protein-encoding gene tolC in the bacterial plant pathogen Erwinia chrysanthemi EC16. The gene was found to encode a 51-kDa protein with 70% identity to its Escherichia coli homologue. The E. chrysanthemi gene was able to functionally complement the E. coli tolC gene with respect to its role in MDR efflux pumps. A tolC mutant of E. chrysanthemi was found to be extremely sensitive to antimicrobial agents, including several plant-derived chemicals. This mutant was unable to grow in planta and its ability to cause plant tissue maceration was severely compromised. The tolC mutant was shown to be defective in the efflux of berberine, a model antimicrobial plant chemical. These results suggest that by conferring resistance to the antimicrobial compounds produced by plants, the E. chrysanthemi tolC plays an important role in the survival and colonization of the pathogen in plant tissue.
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Affiliation(s)
- Ravi D Barabote
- Department of Biological Sciences, Texas Tech University, Lubbock, Texas 79409, USA
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Hahn HP, von Specht BU. Secretory delivery of recombinant proteins in attenuated Salmonella strains: potential and limitations of Type I protein transporters. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2003; 37:87-98. [PMID: 12832111 DOI: 10.1016/s0928-8244(03)00092-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Live attenuated Salmonella strains have been extensively explored as oral delivery systems for recombinant vaccine antigens and effector proteins with immunoadjuvant and immunomodulatory potential. The feasibility of this approach was demonstrated in human vaccination trials for various antigens. However, immunization efficiencies with live vaccines are generally significantly lower compared to those monitored in parenteral immunizations with the same vaccine antigen. This is, at least partly, due to the lack of secretory expression systems, enabling large-scale extracellular delivery of vaccine and effector proteins by these strains. Because of their low complexity and the terminal location of the secretion signal in the secreted protein, Type I (ATP-binding cassette) secretion systems appear to be particularly suited for development of such recombinant extracellular expression systems. So far, the Escherichia coli hemolysin system is the only Type I secretion system, which has been adapted to recombinant protein secretion in Salmonella. However, this system has a number of disadvantages, including low secretion capacity, complex genetic regulation, and structural restriction to the secreted protein, which eventually hinder high-level in vivo delivery of recombinant vaccines and effector proteins. Thus, the development of more efficient recombinant protein secretion systems, based on Type I exporters can help to improve efficacies of live recombinant Salmonella vaccines. Type I secretion systems, mediating secretion of bacterial surface layer proteins, such as RsaA in Caulobacter crescentus, are discussed as promising candidates for improved secretory delivery systems.
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Affiliation(s)
- Heinz P Hahn
- Chirurgische Universitätsklinik, Chirurgische Forschung, i. Br., Freiburg, Germany.
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43
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Feltzer RE, Trent JO, Gray RD. Alkaline proteinase inhibitor of Pseudomonas aeruginosa: a mutational and molecular dynamics study of the role of N-terminal residues in the inhibition of Pseudomonas alkaline proteinase. J Biol Chem 2003; 278:25952-7. [PMID: 12707273 DOI: 10.1074/jbc.m212691200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alkaline proteinase inhibitor of Pseudomonas aeruginosa is a 11.5-kDa, high affinity inhibitor of the serralysin class of zinc-dependent proteinases secreted by several Gram-negative bacteria. X-ray crystallography of the proteinase-inhibitor complex reveals that five N-terminal inhibitor residues occupy the extended substrate binding site of the enzyme and that the catalytic zinc is chelated by the alpha-amino and carbonyl groups of the N-terminal residue of the inhibitor. In this study, we assessed the effect of alteration of inhibitor residues 2-5 on its affinity for Pseudomonas alkaline proteinase (APR) as derived from the ratio of the dissociation and associate rate constants for formation of the enzyme-inhibitor complex. The largest effect was observed at position Ser-2, which occupies the S1' pocket of the enzyme and donates a hydrogen bond to the carboxyl group of the catalytic Glu-177 of the proteinase. Substitution of Asp, Arg, or Trp at this position increased the dissociation constant KD by 35-, 180-, and 13-fold, respectively. Mutation at positions 3-5 of the trunk also resulted in a reduction in enzyme-inhibitor affinity, with the exception of an I4W mutant, which exhibited a 3-fold increase in affinity. Molecular dynamics simulation of the complex formation between the catalytic domain of APR and the S2D mutant showed that the carboxyl of Asp-2 interacts with the catalytic zinc, thereby partially neutralizing the negative charge that otherwise would clash with the carboxyl group of Glu-177 of APR. Simulation of the interaction between the alkaline proteinase and the I4W mutant revealed a major shift in the loop comprised of residues 189-200 of the enzyme that allowed formation of a stacking interaction between the aromatic rings of Ile-4 of the inhibitor and Tyr-158 of the proteinase. This new interaction could account for the observed increase in enzyme-inhibitor affinity.
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Affiliation(s)
- Rhona E Feltzer
- Department of Biochemistry, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA
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Bowen DJ, Rocheleau TA, Grutzmacher CK, Meslet L, Valens M, Marble D, Dowling A, Ffrench-Constant R, Blight MA. Genetic and biochemical characterization of PrtA, an RTX-like metalloprotease from Photorhabdus. MICROBIOLOGY (READING, ENGLAND) 2003; 149:1581-1591. [PMID: 12777498 DOI: 10.1099/mic.0.26171-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Proteases play a key role in the interaction between pathogens and their hosts. The bacterial entomopathogen Photorhabdus lives in symbiosis with nematodes that invade insects. Following entry into the insect, the bacteria are released from the nematode gut into the open blood system of the insect. Here they secrete factors which kill the host and also convert the host tissues into food for the replicating bacteria and nematodes. One of the secreted proteins is PrtA, which is shown here to be a repeats-in-toxin (RTX) alkaline zinc metalloprotease. PrtA has high affinity for artificial substrates such as casein and gelatin and can be inhibited by zinc metalloprotease inhibitors. The metalloprotease also shows a calcium- and temperature-dependent autolysis. The prtA gene carries the characteristic RTX repeated motifs and predicts high similarity to proteases from Erwinia chrysanthemi, Pseudomonas aeruginosa and Serratia marcescens. The prtA gene resides in a locus encoding both the protease ABC transporter (prtBCD) and an intervening ORF encoding a protease inhibitor (inh). PrtA activity is detectable 24 h after artificial bacterial infection of an insect, suggesting that the protease may play a key role in degrading insect tissues rather than in overcoming the insect immune system. Purified PrtA also shows cytotoxicity to mammalian cell cultures, supporting its proposed role in bioconversion of the insect cadaver into food for bacterial and nematode development.
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Affiliation(s)
- David J Bowen
- Department of Entomology, University of Wisconsin-Madison, Madison, USA
| | | | | | - Laurence Meslet
- Institut de Génétique et Microbiologie, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France
| | - Michelle Valens
- Institut de Génétique et Microbiologie, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France
| | - Daniel Marble
- Department of Entomology, University of Wisconsin-Madison, Madison, USA
| | - Andrea Dowling
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, UK
| | | | - Mark A Blight
- Institut de Génétique et Microbiologie, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France
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OMORI KENJI, IDEI AKIKO. Gram-Negative Bacterial ATP-Binding Cassette Protein Exporter Family and Diverse Secretory Proteins. J Biosci Bioeng 2003. [DOI: 10.1263/jbb.95.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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46
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Toth IK, Bell KS, Holeva MC, Birch PRJ. Soft rot erwiniae: from genes to genomes. MOLECULAR PLANT PATHOLOGY 2003; 4:17-30. [PMID: 20569359 DOI: 10.1046/j.1364-3703.2003.00149.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
UNLABELLED SUMMARY The soft rot erwiniae, Erwinia carotovora ssp. atroseptica (Eca), E. carotovora ssp. carotovora (Ecc) and E. chrysanthemi (Ech) are major bacterial pathogens of potato and other crops world-wide. We currently understand much about how these bacteria attack plants and protect themselves against plant defences. However, the processes underlying the establishment of infection, differences in host range and their ability to survive when not causing disease, largely remain a mystery. This review will focus on our current knowledge of pathogenesis in these organisms and discuss how modern genomic approaches, including complete genome sequencing of Eca and Ech, may open the door to a new understanding of the potential subtlety and complexity of soft rot erwiniae and their interactions with plants. TAXONOMY The soft rot erwiniae are members of the Enterobacteriaceae, along with other plant pathogens such as Erwinia amylovora and human pathogens such as Escherichia coli, Salmonella spp. and Yersinia spp. Although the genus name Erwinia is most often used to describe the group, an alternative genus name Pectobacterium was recently proposed for the soft rot species. HOST RANGE Ech mainly affects crops and other plants in tropical and subtropical regions and has a wide host range that includes potato and the important model host African violet (Saintpaulia ionantha). Ecc affects crops and other plants in subtropical and temperate regions and has probably the widest host range, which also includes potato. Eca, on the other hand, has a host range limited almost exclusively to potato in temperate regions only. Disease symptoms: Soft rot erwiniae cause general tissue maceration, termed soft rot disease, through the production of plant cell wall degrading enzymes. Environmental factors such as temperature, low oxygen concentration and free water play an essential role in disease development. On potato, and possibly other plants, disease symptoms may differ, e.g. blackleg disease is associated more with Eca and Ech than with Ecc. USEFUL WEBSITES http://www.scri.sari.ac.uk/TiPP/Erwinia.htm, http://www.ahabs.wisc.edu:16080/ approximately pernalab/erwinia/index.htm, http://www.tigr.org/tdb/mdb/mdbinprogress.html, http://www.sanger.ac.uk/Projects/E_carotovora/.
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Affiliation(s)
- Ian K Toth
- Plant-Pathogen Interactions Programme, Scottish Crop Research Institute, Invergowrie, Dundee DD2 5DA, UK
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Valens M, Broutelle AC, Lefebvre M, Blight MA. A zinc metalloprotease inhibitor, Inh, from the insect pathogen Photorhabdus luminescens. MICROBIOLOGY (READING, ENGLAND) 2002; 148:2427-2437. [PMID: 12177336 DOI: 10.1099/00221287-148-8-2427] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The entomopathogen Photorhabdus luminescens secretes many proteins during the late stages of insect larvae infection and during in vitro laboratory culture. The authors have previously characterized and purified a 55 kDa zinc metalloprotease, PrtA, from culture supernatants of P. luminescens. PrtA is secreted via a classical type I secretory pathway and is encoded within the operon prtA-inh-prtBCD. The 405 bp inh gene encodes a 14.8 kDa pre-protein that is translocated to the periplasm by the classical signal-peptide-dependent sec pathway, yielding the mature 11.9 kDa inhibitor Inh. Inh is a specific inhibitor of the protease PrtA. This study describes the purification of Inh and the initial characterization of its in vitro protease inhibition properties.
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Affiliation(s)
- Michèle Valens
- Institut de Génétique et Microbiologie, Laboratoire de Pathogenèse Comparée, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France1
| | - Anne-Cécile Broutelle
- Institut de Génétique et Microbiologie, Laboratoire de Pathogenèse Comparée, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France1
| | - Mélanie Lefebvre
- Institut de Génétique et Microbiologie, Laboratoire de Pathogenèse Comparée, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France1
| | - Mark A Blight
- Institut de Génétique et Microbiologie, Laboratoire de Pathogenèse Comparée, CNRS UMR 8621, Bâtiment 360, Université Paris XI, 91405 Orsay Cedex, France1
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Fernández L, Secades P, Lopez JR, Márquez I, Guijarro JA. Isolation and analysis of a protease gene with an ABC transport system in the fish pathogen Yersinia ruckeri: insertional mutagenesis and involvement in virulence. MICROBIOLOGY (READING, ENGLAND) 2002; 148:2233-2243. [PMID: 12101310 DOI: 10.1099/00221287-148-7-2233] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Yersinia ruckeri is a Gram-negative pathogen that causes enteric redmouth disease in salmonids. A gene from Y. ruckeri encoding an extracellular protease termed yrp1 (Yersinia ruckeri protease 1) was cloned from a Sau3AI library constructed in pUC19 and analysed in gelatin-supplemented medium. The nucleotide sequence of the yrp1 gene indicated an ORF encoding a protein of 477 aa. On the basis of the high degree of homology in the amino acid sequence as well as its conservative motifs, this protein was included within the serralysin metalloendopeptidase subfamily (EC 3.4.24.12). The yrp1 N-terminal sequence showed a 14 aa propeptide followed by a 10 aa sequence identical to the one deduced previously from the 47 kDa purified protease. Additional results demonstrated that the yrp1 gene encodes the 47 kDa protein. In contrast to other Yersinia species, the yrp1 protease is secreted by a type I Gram-negative bacterial ABC exporter protein secretion system composed of three genes termed yrpD, yrpE and yrpF, and a protease inhibitor inh. The development of genetic methods for this species has allowed the exploration of the organization and the putative role of the Yrp1 genetic locus. Thus, site-directed insertion mutations into the yrp1 and the yrpE genes were constructed by the integration of the mobilizable suicide vector pIVET8 containing internal portions of both coding sequences. Complementation studies of those mutants with different loci indicated that they are organized as a single operon. The mutant strains lacked protease activity as well as the Yrp1 protein and, although physiologically similar to the parental strain when growing on nutrient broth medium, they were attenuated in virulence when bacteria were injected intraperitoneally into rainbow trout (Oncorhynchus mykiss). This is the first report of defined mutations in Y. ruckeri to show the implication of a factor such as an extracellular protease in pathogenesis.
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Affiliation(s)
- L Fernández
- Área de Microbiologia, Departamento de Biologia Funcional, Facultad de Medicina, Instituto Universitario de Biotecnologia de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain1
| | - P Secades
- Área de Microbiologia, Departamento de Biologia Funcional, Facultad de Medicina, Instituto Universitario de Biotecnologia de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain1
| | - J R Lopez
- Área de Microbiologia, Departamento de Biologia Funcional, Facultad de Medicina, Instituto Universitario de Biotecnologia de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain1
| | - I Márquez
- SERIDA, Laboratorio de Sanidad Animal de Jove, 33299 Gijon, Spain2
| | - J A Guijarro
- Área de Microbiologia, Departamento de Biologia Funcional, Facultad de Medicina, Instituto Universitario de Biotecnologia de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain1
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Marits R, Tshuikina M, Pirhonen M, Laasik E, Mäe A. Regulation of the expression of prtW::gusA fusions in Erwinia carotovora subsp. carotovora. MICROBIOLOGY (READING, ENGLAND) 2002; 148:835-842. [PMID: 11882719 DOI: 10.1099/00221287-148-3-835] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Erwinia carotovora subsp. carotovora, a Gram-negative phytopathogenic bacterium, secretes an extracellular metalloprotease, PrtW. Previous results demonstrated that protease activity is necessary for the normal progression of disease symptoms caused by this bacterium. The present study revealed that the prtW gene constitutes an independent transcriptional unit. It is demonstrated that introduction of the prtW(+) plasmid in trans into the prtW(-) mutant restores the protease activity in this strain. Gene fusions to the gusA (beta-glucuronidase) reporter were employed to analyse the transcription of prtW. The transcription of prtW is dependent on many environmental signals. When the bacteria were grown in the presence of potato extract, the expression of the protease gene was markedly higher at the beginning of the exponential phase of growth than that observed when cells were grown in the presence of polygalacturonate (PGA). Analysis of the promoter revealed that an essential regulatory region resided between 371 and 245 bp 5' of the translational start site. As this sequence showed no homology to the KdgR box it may be involved in the binding of an unknown negative regulator protein in E. carotovora subsp. carotovora. The differential responses of prtW expression to potato extract and to PGA appeared to be dependent on the KdgR repressor and the response regulator ExpA. According to the results presented here, it is conceivable that the multiple regulatory network allows flexibility in the expression of the prtW gene during different stages of infection.
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Affiliation(s)
- Reet Marits
- Department of Genetics Institute of Molecular and Cell Biology, Tartu University Estonian Biocentre, Riia 23, Tartu 51010, Estonia1
| | - Marina Tshuikina
- Department of Genetics Institute of Molecular and Cell Biology, Tartu University Estonian Biocentre, Riia 23, Tartu 51010, Estonia1
| | - Minna Pirhonen
- Department of Plant Biology, Swedish University of Agricultural Sciences (SLU), PO Box 7080, SE-75007 Uppsala, Sweden2
| | - Eve Laasik
- Department of Genetics Institute of Molecular and Cell Biology, Tartu University Estonian Biocentre, Riia 23, Tartu 51010, Estonia1
| | - Andres Mäe
- Department of Genetics Institute of Molecular and Cell Biology, Tartu University Estonian Biocentre, Riia 23, Tartu 51010, Estonia1
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Sapriel G, Wandersman C, Delepelaire P. The N terminus of the HasA protein and the SecB chaperone cooperate in the efficient targeting and secretion of HasA via the ATP-binding cassette transporter. J Biol Chem 2002; 277:6726-32. [PMID: 11698405 DOI: 10.1074/jbc.m108632200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Secretion of the HasA hemophore is mediated by a C-terminal secretion signal as part of an ATP-binding cassette (ABC) pathway in the Gram-negative bacterium Serratia marcescens. We reconstituted the HasA secretion pathway in Escherichia coli. In E. coli, this pathway required three specific secretion functions and SecB, the general chaperone of the Sec pathway that recognizes HasA. The secretion of the isolated C-terminal secretion signal was not SecB-dependent. We have previously shown that intracellular folded HasA can no longer be secreted, and we proposed a step in the secretion process before the recognition of the secretion signal. Here we show that the secretion of a fully functional HasA variant, lacking the first 10 N-terminal amino acids, was less efficient than that of HasA and was SecB-independent. The N terminus of HasA was required, along with SecB, for the efficient secretion of the whole protein. We have also previously shown that HasA inhibits the secretion of metalloproteases from Erwinia chrysanthemi by their specific ABC transporter. Here we show that this abortive interaction between HasA and the E. chrysanthemi metalloprotease ABC transporter required both SecB and the N terminus of HasA. N-terminal fragments of HasA displayed this abortive interaction in vivo and also interacted specifically in vitro with the ABC protein of the Prt system. SecB also interacted specifically in vitro with the ABC protein of the Prt system. Finally, the HasA variant, lacking the first 10 N-terminal amino acids did not display this abortive interaction with the Prt system. We suggest that the N-terminal domain of HasA specifically recognizes the ABC protein in a SecB-dependent fashion, facilitating functional interaction with the C-terminal secretion signal leading to efficient secretion.
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Affiliation(s)
- Guillaume Sapriel
- Unité des Membranes Bactériennes, CNRS URA 2172, Dpt des Biotechnologies, Institut Pasteur, 25-28, rue du Dr. Roux, 75724 Paris Cedex 15, France.
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