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Li K, Zhu Y, Yan W, Deng X, Xiao Y, Song L, Fang R, Jia Y, Tang X. Two components of the rhpPC operon coordinately regulate the type III secretion system and bacterial fitness in Pseudomonas savastanoi pv. phaseolicola. PLoS Pathog 2019; 15:e1007673. [PMID: 30998769 PMCID: PMC6490944 DOI: 10.1371/journal.ppat.1007673] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 04/30/2019] [Accepted: 03/02/2019] [Indexed: 12/17/2022] Open
Abstract
Many plant bacterial pathogens including Pseudomonas species, utilize the type III secretion system (T3SS) to deliver effector proteins into plant cells. Genes encoding the T3SS and its effectors are repressed in nutrient-rich media but are rapidly induced after the bacteria enter a plant or are transferred into nutrient-deficient media. To understand how the T3SS genes are regulated, we screened for P. savastanoi pv. phaseolicola (Psph) mutants displaying diminished induction of avrPto-luc, a reporter for the T3SS genes, in Arabidopsis. A mutant carrying transposon insertion into a gene coding for a small functional unknown protein, designated as rhpC, was identified that poorly induced avrPto-luc in plants and in minimal medium (MM). Interestingly, rhpC is located immediately downstream of a putative metalloprotease gene named rhpP, and the two genes are organized in an operon rhpPC; but rhpP and rhpC displayed different RNA expression patterns in nutrient-rich King’s B medium (KB) and MM. Deletion of the whole rhpPC locus did not significantly affect the avrPto-luc induction, implying coordinated actions of rhpP and rhpC in regulating the T3SS genes. Further analysis showed that RhpC was a cytoplasmic protein that interacted with RhpP and targeted RhpP to the periplasm. In the absence of RhpC, RhpP was localized in the cytoplasm and caused a reduction of HrpL, a key regulator of the T3SS genes, and also reduced the fitness of Psph. Expression of RhpP alone in E. coli inhibited the bacterial growth. The detrimental effect of RhpP on the fitness of Psph and E. coli required metalloprotease active sites, and was repressed when RhpC was co-expressed with RhpP. The coordination between rhpP and rhpC in tuning the T3SS gene expression and cell fitness reveals a novel regulatory mechanism for bacterial pathogenesis. The function of RhpP in the periplasm remains to be studied. The induction of the type III secretion system (T3SS) is of great importance to the pathogenesis of bacterial pathogens in host plants. Pseudomonas savastanoi pv. phaseolicola (Psph) causes halo blight disease on beans. We discovered that the bicistronic genes in the rhpPC locus of Psph act coordinately to regulate the T3SS gene expression, bacterial fitness, and pathogenicity. rhpP encodes a metalloprotease that can degrade the key T3SS regulator protein HrpL and reduce bacterial fitness. rhpC encodes a chaperone that inhibits the RhpP activity and mediates translocation of RhpP to the periplasm. The level of rhpP RNA is high in KB but decreases in MM, but the rhpC RNA is low in KB but increases in MM. The elevated rhpC/rhpP transcript ratio in MM plus the inhibition of RhpC on RhpP activity in cytoplasm provide double insurance that warrants high induction of the T3SS genes in MM and bacterial fitness. The coordination between rhpP and rhpC reveals a new mechanism regulating bacterial pathogenicity, and may provide an important target for controlling bacterial pathogens.
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Affiliation(s)
- Kun Li
- Guangdong Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- School of Life Sciences, Capital Normal University, Beijing, China
| | - Yanan Zhu
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- School of Life Sciences, Capital Normal University, Beijing, China
| | - Wei Yan
- Guangdong Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Xin Deng
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Yanmei Xiao
- Department of Plant Pathology, Kansas State University, Kansas, United States of America
| | - Liyang Song
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Rongxiang Fang
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- * E-mail: (RF); (YJ); (XT)
| | - Yantao Jia
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- National Plant Gene Research Center, Beijing, China
- * E-mail: (RF); (YJ); (XT)
| | - Xiaoyan Tang
- Guangdong Key Lab of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
- * E-mail: (RF); (YJ); (XT)
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Bogdanović X, Palm GJ, Schwenteit J, Singh RK, Gudmundsdóttir BK, Hinrichs W. Structural evidence of intramolecular propeptide inhibition of the aspzincin metalloendopeptidase AsaP1. FEBS Lett 2016; 590:3280-94. [DOI: 10.1002/1873-3468.12356] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 08/03/2016] [Accepted: 08/05/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Xenia Bogdanović
- Department of Molecular Structural Biology; Institute for Biochemistry; University of Greifswald; Germany
- Institute for Biochemistry and Molecular Biology; ZBMZ; Medical Faculty; University of Freiburg; Freiburg im Breisgau Germany
| | - Gottfried J. Palm
- Department of Molecular Structural Biology; Institute for Biochemistry; University of Greifswald; Germany
| | - Johanna Schwenteit
- Department of Molecular Structural Biology; Institute for Biochemistry; University of Greifswald; Germany
- Institute for Experimental Pathology; University of Iceland, Keldur; Reykjavík Iceland
| | - Rajesh K. Singh
- Department of Molecular Structural Biology; Institute for Biochemistry; University of Greifswald; Germany
| | | | - Winfried Hinrichs
- Department of Molecular Structural Biology; Institute for Biochemistry; University of Greifswald; Germany
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3
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Houston S, Hof R, Honeyman L, Hassler J, Cameron CE. Activation and proteolytic activity of the Treponema pallidum metalloprotease, pallilysin. PLoS Pathog 2012; 8:e1002822. [PMID: 22910436 PMCID: PMC3406077 DOI: 10.1371/journal.ppat.1002822] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 06/12/2012] [Indexed: 11/19/2022] Open
Abstract
Treponema pallidum is a highly invasive pathogen that undergoes rapid dissemination to establish widespread infection. Previous investigations identified the T. pallidum adhesin, pallilysin, as an HEXXH-containing metalloprotease that undergoes autocatalytic cleavage and degrades laminin and fibrinogen. In the current study we characterized pallilysin's active site, activation requirements, cellular location, and fibrin clot degradation capacity through both in vitro assays and heterologous treponemal expression and degradation studies. Site-directed mutagenesis showed the pallilysin HEXXH motif comprises at least part of the active site, as introduction of three independent mutations (AEXXH [H198A], HAXXH [E199A], and HEXXA [H202A]) abolished pallilysin-mediated fibrinogenolysis but did not adversely affect host component binding. Attainment of full pallilysin proteolytic activity was dependent upon autocatalytic cleavage of an N-terminal pro-domain, a process which could not occur in the HEXXH mutants. Pallilysin was shown to possess a thrombin cleavage site within its N-terminal pro-domain, and in vitro studies confirmed cleavage of pallilysin with thrombin generates a truncated pallilysin fragment that has enhanced proteolytic activity, suggesting pallilysin can also exploit the host coagulation process to facilitate protease activation. Opsonophagocytosis assays performed with viable T. pallidum demonstrated pallilysin is a target of opsonic antibodies, consistent with a host component-interacting, surface-exposed cellular location. Wild-type pallilysin, but not the HEXXA mutant, degraded fibrin clots, and similarly heterologous expression of pallilysin in the non-invasive spirochete Treponema phagedenis facilitated fibrin clot degradation. Collectively these results identify pallilysin as a surface-exposed metalloprotease within T. pallidum that possesses an HEXXH active site motif and requires autocatalytic or host-mediated cleavage of a pro-domain to attain full host component-directed proteolytic activity. Furthermore, our finding that expression of pallilysin confers upon T. phagedenis the capacity to degrade fibrin clots suggests this capability may contribute to the dissemination potential of T. pallidum. Syphilis, caused by the spirochete Treponema pallidum, is a chronic sexually transmitted disease which infects 12 million people annually. Treponema pallidum is highly invasive and undergoes widespread dissemination via the circulatory system. Similar to other invasive pathogens, T. pallidum has been shown to express a host-component-degrading protease, pallilysin, that binds and degrades human fibrinogen and laminin, suggesting a role for pallilysin in bacterial dissemination. Here we identify pallilysin active site residues using mutagenesis and show that, unlike wild-type, mutants fail to degrade fibrinogen. We show that pallilysin is converted into a highly proteolytically active form via truncation of a pro-domain through either autocatalytic cleavage or host-derived, thrombin-mediated cleavage. We also demonstrate that recombinant pallilysin enables clot dissolution and that pallilysin expressed on the surface of the non-invasive spirochete Treponema phagedenis confers the ability to degrade fibrin clots. Further, we show that pallilysin is present on the surface of T. pallidum and thus resides in a cellular location that facilitates direct contact with host components. Our study provides insight into the mechanism of interaction between pallilysin and two important coagulation system proteins, fibrinogen and thrombin, and suggests a novel mechanism that T. pallidum may utilize for dissemination during infection.
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Affiliation(s)
- Simon Houston
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Rebecca Hof
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Lisa Honeyman
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Julia Hassler
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
| | - Caroline E. Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada
- * E-mail:
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Oman TJ, van der Donk WA. Follow the leader: the use of leader peptides to guide natural product biosynthesis. Nat Chem Biol 2010; 6:9-18. [PMID: 20016494 PMCID: PMC3799897 DOI: 10.1038/nchembio.286] [Citation(s) in RCA: 292] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The avalanche of genomic information in the past decade has revealed that natural product biosynthesis using the ribosomal machinery is much more widespread than originally anticipated. Nearly all of these compounds are crafted through post-translational modifications of a larger precursor peptide that often contains the marching orders for the biosynthetic enzymes. We review here the available information for how the peptide sequences in the precursors govern the post-translational tailoring processes for several classes of natural products. In addition, we highlight the great potential these leader peptide-directed biosynthetic systems offer for engineering conformationally restrained and pharmacophore-rich products with structural diversity that greatly expands the proteinogenic repertoire.
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Affiliation(s)
- Trent J. Oman
- Department of Chemistry, Howard Hughes Medical Institute, and Institute for Genomic Biology. University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, Telephone: (217) 244 5360, FAX: (217) 244 8533
| | - Wilfred A. van der Donk
- Department of Chemistry, Howard Hughes Medical Institute, and Institute for Genomic Biology. University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, Telephone: (217) 244 5360, FAX: (217) 244 8533
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5
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Heterologous production of Escherichia coli penicillin G acylase in Pseudomonas aeruginosa. J Biotechnol 2009; 142:250-8. [DOI: 10.1016/j.jbiotec.2009.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 05/18/2009] [Accepted: 05/19/2009] [Indexed: 11/22/2022]
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Thibodeaux BA, Caballero AR, Marquart ME, Tommassen J, O'Callaghan RJ. Corneal virulence of Pseudomonas aeruginosa elastase B and alkaline protease produced by Pseudomonas putida. Curr Eye Res 2007; 32:373-86. [PMID: 17453960 DOI: 10.1080/02713680701244181] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To measure the specific virulence contributions of two Pseudomonas aeruginosa proteases, elastase B and alkaline protease, when expressed separately by Pseudomonas putida in a rabbit model of bacterial keratitis. METHODS P. putida KT2440 was transformed with plasmids that enabled the extracellular production of either elastase or alkaline protease. Protease expression was confirmed by zymography and immunoblotting. P. putida expressing elastase, alkaline protease, or vector alone was injected intrastromally (10(3) colony forming units [CFU]) into rabbit corneas (n=6). Infected eyes were graded by slit-lamp examination (SLE) at 20, 24, 28, and 32 hr postinfection (PI). Rabbits were sacrificed at 33 hr PI, and the log CFU (+/-SEM) per cornea was determined. RESULTS SLE scores for eyes infected with P. putida producing elastase were significantly higher than those infected with vector alone at all time points (p<or=0.008). SLE scores for eyes infected with P. putida producing alkaline protease were not significantly higher than the control (p>or=0.1), but small erosions formed in 33% of corneas. At both 24 and 28 hr PI, the SLE scores for corneas infected with P. putida producing elastase were significantly higher than those infected with P. putida producing alkaline protease (p<or=0.002). CONCLUSIONS Elastase production by P. putida caused significant increases in SLE scores whereas expression of alkaline protease caused limited corneal erosions. This suggests that the production of elastase during P. aeruginosa keratitis enhances ocular pathology, whereas alkaline protease production contributes to limited corneal erosion.
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Affiliation(s)
- Brett A Thibodeaux
- Department of Microbiology, Immunology, and Parasitology, LSU Health Sciences Center, New Orleans, Louisiana, USA
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7
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Ireland DC, Colgrave ML, Nguyencong P, Daly NL, Craik DJ. Discovery and Characterization of a Linear Cyclotide from Viola odorata: Implications for the Processing of Circular Proteins. J Mol Biol 2006; 357:1522-35. [PMID: 16488428 DOI: 10.1016/j.jmb.2006.01.051] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 01/11/2006] [Accepted: 01/12/2006] [Indexed: 10/25/2022]
Abstract
Cyclotides are mini-proteins of 28-37 amino acid residues that have the unusual feature of a head-to-tail cyclic backbone surrounding a cystine knot. This molecular architecture gives the cyclotides heightened resistance to thermal, chemical and enzymatic degradation and has prompted investigations into their use as scaffolds in peptide therapeutics. There are now more than 80 reported cyclotide sequences from plants in the families Rubiaceae, Violaceae and Cucurbitaceae, with a wide variety of biological activities observed. However, potentially limiting the development of cyclotide-based therapeutics is a lack of understanding of the mechanism by which these peptides are cyclized in vivo. Until now, no linear versions of cyclotides have been reported, limiting our understanding of the cyclization mechanism. This study reports the discovery of a naturally occurring linear cyclotide, violacin A, from the plant Viola odorata and discusses the implications for in vivo cyclization of peptides. The elucidation of the cDNA clone of violacin A revealed a point mutation that introduces a stop codon, which inhibits the translation of a key Asn residue that is thought to be required for cyclization. The three-dimensional solution structure of violacin A was determined and found to adopt the cystine knot fold of native cyclotides. Enzymatic stability assays on violacin A indicate that despite an increase in the flexibility of the structure relative to cyclic counterparts, the cystine knot preserves the overall stability of the molecule.
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Affiliation(s)
- David C Ireland
- Institute for Molecular Bioscience and Australian Research Council Special Research Centre for Functional and Applied Genomics, University of Queensland, Brisbane, Qld 4072, Australia
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8
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Yeung PSM, Zagorski N, Marquis H. The metalloprotease of Listeria monocytogenes controls cell wall translocation of the broad-range phospholipase C. J Bacteriol 2005; 187:2601-8. [PMID: 15805506 PMCID: PMC1070396 DOI: 10.1128/jb.187.8.2601-2608.2005] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes is a gram-positive bacterial pathogen that multiplies in the cytosol of host cells and spreads directly from cell to cell. During cell-to-cell spread, bacteria become temporarily confined to secondary vacuoles. The broad-range phospholipase C (PC-PLC) of L. monocytogenes contributes to bacterial escape from secondary vacuoles. PC-PLC requires cleavage of an N-terminal propeptide for activation, and Mpl, a metalloprotease of Listeria, is involved in the proteolytic activation of PC-PLC. Previously, we showed that cell wall translocation of PC-PLC is inefficient, resulting in accumulation of PC-PLC at the membrane-cell wall interface. In infected cells, rapid cell wall translocation of PC-PLC is triggered by a decrease in pH and correlates with cleavage of the propeptide in an Mpl-dependent manner. To address the role of the propeptide and of Mpl in cell wall translocation of PC-PLC, we generated a cleavage site mutant and a propeptide deletion mutant. The intracellular behavior of these mutants was assessed in pulse-chase experiments. We observed efficient translocation of the proform of the PC-PLC cleavage site mutant in a manner that was pH sensitive and Mpl dependent. However, the propeptide deletion mutant was efficiently translocated into host cells independent of Mpl and pH. Overall, these results suggest that Mpl regulates PC-PLC translocation across the bacterial cell wall in a manner that is dependent on the presence of the propeptide but independent of propeptide cleavage. In addition, similarly to Mpl-mediated cleavage of PC-PLC propeptide, Mpl-mediated translocation of PC-PLC across the bacterial cell wall is pH sensitive.
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Affiliation(s)
- P S Marie Yeung
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14853-4601, USA
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9
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Dutton JL, Renda RF, Waine C, Clark RJ, Daly NL, Jennings CV, Anderson MA, Craik DJ. Conserved Structural and Sequence Elements Implicated in the Processing of Gene-encoded Circular Proteins. J Biol Chem 2004; 279:46858-67. [PMID: 15328347 DOI: 10.1074/jbc.m407421200] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The cyclotides are the largest family of naturally occurring circular proteins. The mechanism by which the termini of these gene-encoded proteins are linked seamlessly with a peptide bond to form a circular backbone is unknown. Here we report cyclotide-encoding cDNA sequences from the plant Viola odorata and compare them with those from an evolutionarily distinct species, Oldenlandia affinis. Individual members of this multigene family encode one to three mature cyclotide domains. These domains are preceded by N-terminal repeat regions (NTRs) that are conserved within a plant species but not between species. We have structurally characterized peptides corresponding to these NTRs and show that, despite them having no sequence homology, they form a structurally conserved alpha-helical motif. This structural conservation suggests a vital role for the NTR in the in vivo folding, processing, or detoxification of cyclotide domains from the precursor protein.
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Affiliation(s)
- Julie L Dutton
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Quuensland 4072, Australia
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10
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Abstract
Lipases represent the most important class of enzymes used in biotechnology. Many bacteria produce and secrete lipases but the enzymes originating from Pseudomonas and Burkholderia species seem to be particularly useful for a wide variety of different biocatalytic applications. These enzymes are usually encoded in an operon together with a second gene which codes for a lipase-specific foldase, Lif, which is necessary to obtain enzymatically active lipase. A detailed analysis based on amino acid homology has suggested the classification of Lif proteins into four different families and also revealed the presence of a conserved motif, Rx1x2FDY(F/C)L(S/T)A. Recent experimental evidence suggests that Lifs are so-called steric chaperones, which exert their physiological function by lowering energetic barriers during the folding of their cognate lipases, thereby providing essential steric information needed to fold lipases into their enzymatically active conformation.
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Affiliation(s)
- Frank Rosenau
- Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, 52428 Jülich, Germany
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Maupin-Furlow JA, Kaczowka SJ, Reuter CJ, Zuobi-Hasona K, Gil MA. Archaeal proteasomes: potential in metabolic engineering. Metab Eng 2003; 5:151-63. [PMID: 12948749 DOI: 10.1016/s1096-7176(03)00030-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Archaea are a valuable source of enzymes for industrial and scientific applications because of their ability to survive extreme conditions including high salt and temperature. Thanks to advances in molecular biology and genetics, archaea are also attractive hosts for metabolic engineering. Understanding how energy-dependent proteases and chaperones function to maintain protein quality control is key to high-level synthesis of recombinant products. In archaea, proteasomes are central players in energy-dependent proteolysis and form elaborate nanocompartments that degrade proteins into oligopeptides by processive hydrolysis. The catalytic core responsible for this proteolytic activity is the 20S proteasome, a barrel-shaped particle with a central channel and axial gates on each end that limit substrate access to a central proteolytic chamber. AAA proteins (ATPases associated with various cellular activities) are likely to play several roles in mediating energy-dependent proteolysis by the proteasome. These include ATP binding/hydrolysis, substrate binding/unfolding, opening of the axial gates, and translocation of substrate into the proteolytic chamber.
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Affiliation(s)
- Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Room 1052, Building 981, Gainesville, FL 32611-0700, USA.
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Nomura T, Fujii Y, Yamanaka H, Kobayashi H, Okamoto K. The protein encoded at the 3' end of the serine protease gene of Aeromonas sobria functions as a chaperone in the production of the protease. J Bacteriol 2002; 184:7058-61. [PMID: 12446656 PMCID: PMC135477 DOI: 10.1128/jb.184.24.7058-7061.2002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For the successful production of Aeromonas sobria serine protease (ASP), open reading frame 2 (ORF2) protein, encoded at the 3' end of the protease operon, is required. In this study, we examined the action of ORF2 protein. The results showed that the protein associated with ASP in the periplasm and helped ASP to form an active structure.
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Affiliation(s)
- Tomohiko Nomura
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro, Japan.
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Maupin-Furlow JA, Kaczowka SJ, Ou MS, Wilson HL. Archaeal proteasomes: proteolytic nanocompartments of the cell. ADVANCES IN APPLIED MICROBIOLOGY 2002; 50:279-338. [PMID: 11677686 DOI: 10.1016/s0065-2164(01)50008-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- J A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611-0700, USA
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Braun P, Bitter W, Tommassen J. Activation of Pseudomonas aeruginosa elastase in Pseudomonas putida by triggering dissociation of the propeptide-enzyme complex. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 10):2565-2572. [PMID: 11021931 DOI: 10.1099/00221287-146-10-2565] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The propeptide of Pseudomonas aeruginosa elastase functions both as an intramolecular chaperone required for the folding of the enzyme and as an inhibitor that prevents activity of the enzyme before its secretion into the extracellular medium. Since expression of the lasB gene, which encodes elastase, in Pseudomonas putida did not result in extracellular elastase activity, it has been suggested that the enzyme is not recognized by the Xcp secretion machinery of the heterologous host. Here, it is demonstrated that the proenzyme is normally processed in P. putida and that it is indeed not actively secreted by the Xcp machinery. Nevertheless, substantial amounts of the enzyme were detected in the extracellular medium. Co-immunoprecipitations revealed that the extracellular enzyme was associated with the propeptide, which explains the lack of enzymic activity. Since the propeptide-enzyme complex in P. putida apparently does not dissociate spontaneously, it is concluded that a host-specific factor is required to induce this event. Mutants were selected which showed extracellular elastase activity. Two mutations, located within the lasB gene, were further characterized. These mutations, resulting in the substitution of Ala and Thr at positions -15 and -153, respectively, of the propeptide (where position +1 is defined as the first residue of the mature enzyme) destabilized the propeptide-enzyme complex. It is concluded that Ala-15 and Thr-153 are required for the inhibitor function, but not for the chaperone function of the propeptide.
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Affiliation(s)
- Peter Braun
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands1
| | - Wilbert Bitter
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands1
| | - Jan Tommassen
- Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands1
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Nomura T, Hamashima H, Okamoto K. Carboxy terminal region of haemolysin of Aeromonas sobria triggers dimerization. Microb Pathog 2000; 28:25-36. [PMID: 10623561 DOI: 10.1006/mpat.1999.0321] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Haemolysin of Aeromonas sobria is released into the culture supernatant in the form of prohaemolysin. Removal of a 42 amino acid peptide at the carboxy-terminal end converts prohaemolysin into mature haemolysin. As the role of the peptide removed from the mature haemolysin has not been studied, we mutated the haemolysin genes to delete several amino acid residues from the carboxy terminus, expressed the mutant genes in A. sobria and analysed the haemolysins produced. Deletion of more than three amino acid residues significantly reduced the efficiency of secretion of haemolysin into the culture supernatant. Mutant haemolysins with deletion of 10 amino acids were easily degraded in cells. Furthermore, cross-linking experiments indicated that the haemolysins dimerize in cells, and thus dimerized haemolysins are translocated across the outer membrane and appear in the culture supernatant. These results indicated that the carboxy-terminal end of prohaemolysin triggers dimerization of haemolysin in cells, resulting in the efficient secretion of haemolysin into the culture supernatant.
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Affiliation(s)
- T Nomura
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Yamashiro, Tokushima, 770-8514, Japan
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Nomura T, Fujii Y, Okamoto K. Secretion of hemolysin of Aeromonas sobria as protoxin and contribution of the propeptide region removed from the protoxin to the proteolytic stability of the toxin. Microbiol Immunol 1999; 43:29-38. [PMID: 10100744 DOI: 10.1111/j.1348-0421.1999.tb02369.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sequence at the amino terminus region of the hemolysin ofAeromonas sobria is homologous with that of aerolysin of A. hydrophila. However, there is no homology between the two toxins in the sequence at the carboxy terminal region. It has been shown that aerolysin is secreted into culture supernatant as a protoxin. This proaerolysin is activated by the proteolytic removal of a carboxy terminal peptide. However, the role of the carboxy terminal region, which is removed in the activation process, has not been elucidated. In this study, we showed that hemolysin is also secreted as a protoxin into culture supernatant and that prohemolysin is cleaved by the protease of A. sobria between Ser-446 and Ala-447, resulting in the removal of a 42 amino acid peptide. The removal of the peptide converts the prohemolysin into active hemolysin. Subsequently, we mutated the hemolysin gene to delete the last several amino acid residues and expressed the genes in Escherichia coli, in order to examine the role of the carboxy terminal region of prohemolysin. The amounts of these mutant hemolysins accumulated in the periplasmic space of E. coli were very low compared with that of the wild-type. This observation indicated that the carboxy terminal region of prohemolysin contributes to the proteolytic stability of the toxin.
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Affiliation(s)
- T Nomura
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, Japan
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