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Sun J, Yan B, Chen H, Tu S, Zhang J, Chen T, Huang Q, Zhang Y, Xie L. Insight into the mechanisms of combined toxicity of cadmium and flotation agents in luminescent bacteria: Role of micro/nano particles. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 940:173588. [PMID: 38823693 DOI: 10.1016/j.scitotenv.2024.173588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/22/2024] [Accepted: 05/26/2024] [Indexed: 06/03/2024]
Abstract
Currently, risk assessment and pollution management in mines primarily focus on toxic metals, with the flotation agents being overlooked. However, the combined effects of metals and flotation agents in mines remain largely unknown. Therefore, this study aimed to evaluate the combined effects of Cd and two organic flotation agents (ethyl xanthate (EX) and diethyldithiocarbamate (DDTC)), and the associated mechanisms. The results showed that Cd + EX and Cd + DDTC exhibited synergistic toxicity. The EC50 values for luminescent bacteria were 1.6 mg/L and 1.0 mg/L at toxicity unit ratios of 0.3 and 1, respectively. The synergistic effects were closely related with the formation of Cd(EX)2 and Cd(DDTC)2 micro/nano particles, with nano-particles exhibiting higher toxicity. We observed severe cell membrane damage and cell shrinkage of the luminescent bacteria, which were probably caused by secondary harm to cells through the released CS2 during their decomposition inside cells. In addition, these particles induced toxicity by altering cellular levels of biochemical markers and the transcriptional levels of transport proteins and lipoproteins, leading to cell membrane impairment and DNA damage. This study has demonstrated that particulates formed by Cd and flotation agents contribute to the majority of the toxicity of the binary mixture. This study helps to better understand the complex ecological risk of inorganic metals and organic flotation agents in realistic mining environments.
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Affiliation(s)
- Jiacheng Sun
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Bo Yan
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China.
| | - Hongxing Chen
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China.
| | - Shuchen Tu
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Junhao Zhang
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Tao Chen
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Qinzi Huang
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Yuting Zhang
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
| | - Lingtian Xie
- School of Environment, South China Normal University, University Town, Guangzhou 510006, China; SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China
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Vercruysse M, Dylus D. Special issue of BBA reviews — Molecular Cell Research: The Gram-negative envelope and potential targets for novel antibiotics. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2023; 1870:119472. [PMID: 37011731 DOI: 10.1016/j.bbamcr.2023.119472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/08/2023] [Accepted: 02/27/2023] [Indexed: 04/03/2023]
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El Rayes J, Rodríguez-Alonso R, Collet JF. Lipoproteins in Gram-negative bacteria: new insights into their biogenesis, subcellular targeting and functional roles. Curr Opin Microbiol 2021; 61:25-34. [PMID: 33667939 DOI: 10.1016/j.mib.2021.02.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023]
Abstract
Bacterial lipoproteins are globular proteins anchored to a membrane by a lipid moiety. By discovering new functions carried out by lipoproteins, recent research has highlighted the crucial roles played by these proteins in the cell envelope of Gram-negative bacteria. Here, after discussing the wide range of activities carried out by lipoproteins in the model bacterium Escherichia coli, we review new insights into the essential mechanisms involved in lipoprotein maturation, sorting and targeting to their final destination. A special attention will also be given to the recent identification of lipoproteins on the surface of E. coli and of other bacteria. The renewed interest in lipoproteins is driven by the need to identify novel targets for antibiotic development.
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Affiliation(s)
- Jessica El Rayes
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium; de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Raquel Rodríguez-Alonso
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium; de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Jean-François Collet
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium; de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, 1200 Brussels, Belgium.
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Zhan T, Chen Q, Zhang C, Bi C, Zhang X. Constructing a Novel Biosynthetic Pathway for the Production of Glycolate from Glycerol in Escherichia coli. ACS Synth Biol 2020; 9:2600-2609. [PMID: 32794740 DOI: 10.1021/acssynbio.0c00404] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glycolate is an important α-hydroxy acid with a wide range of industrial applications. The current industrial production of glycolate mainly depends on chemical synthesis, but biochemical production from renewable resources using engineered microorganisms is increasingly viewed as an attractive alternative. Crude glycerol is an abundant byproduct of biodiesel production and a widely investigated potential sustainable feedstock. Here, we constructed a novel biosynthetic pathway for the production of glycolate from glycerol in Escherichia coli. The pathway starts from the oxidation of glycerol to d-glycerate by alditol oxidase, followed by sequential enzymatic dehydrogenation and decarboxylation as well as reduction reactions. We screened and characterized the catalytic activity of candidate enzymes, and a variant of alditol oxidase from Streptomyces coelicolor A3(2), 2-hydroxyglutarate-pyruvate transhydrogenase from Saccharomyces cerevisiae, α-ketoisovalerate decarboxylase from Lactococcus lactis, and aldehyde dehydrogenase from Escherichia coli were selected and assembled to create an artificial operon for the biosynthetic production of glycolate from glycerol. We also characterized the native strong constitutive promoter Plpp from E. coli and compared it with the PT7 promoter, which was employed to express the artificial operon on the plasmid pSC105-ADKA. To redirect glycerol flux toward glycolate synthesis, we deleted key genes of the native glycerol assimilation pathways and other branches of native E. coli metabolism, and we introduced a second plasmid expressing Dld3 to reduce the accumulation of the intermediate d-glycerate. Finally, the engineered strain TZ-108 harboring pSC105-ADKA and pACYC184-Plpp-Dld3 produced 0.64 g/L glycolate in shake flasks, which was increased to 4.74 g/L in fed-batch fermentation. This study provides an alternative pathway for glycolate synthesis and demonstrates the potential for producing other commodity chemicals by redesigning glycerol metabolism.
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Affiliation(s)
- Tao Zhan
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Qian Chen
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Chao Zhang
- College of Chemistry and Life Sciences, Changchun University of Technology, Changchun, Jilin 130012, China
| | - Changhao Bi
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Xueli Zhang
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
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Abstract
The Lpp lipoprotein of Escherichia coli is the first identified protein with a covalently linked lipid. It is chemically bound by its C-terminus to murein (peptidoglycan) and inserts by the lipid at the N-terminus into the outer membrane. As the most abundant protein in E. coli (106 molecules per cell) it plays an important role for the integrity of the cell envelope. Lpp represents the type protein of a large variety of lipoproteins found in Gram-negative and Gram-positive bacteria and in archaea that have in common the lipid structure for anchoring the proteins to membranes but otherwise strongly vary in sequence, structure, and function. Predicted lipoproteins in known prokaryotic genomes comprise 2.7% of all proteins. Lipoproteins are modified by a unique phospholipid pathway and transferred from the cytoplasmic membrane into the outer membrane by a special system. They are involved in protein incorporation into the outer membrane, protein secretion across the cytoplasmic membrane, periplasm and outer membrane, signal transduction, conjugation, cell wall metabolism, antibiotic resistance, biofilm formation, and adhesion to host tissues. They are only found in bacteria and function as signal molecules for the innate immune system of vertebrates, where they cause inflammation and elicit innate and adaptive immune response through Toll-like receptors. This review discusses various aspects of Lpp and other lipoproteins of Gram-negative and Gram-positive bacteria and archaea.
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Affiliation(s)
- Volkmar Braun
- Department of Protein Evolution, Max Planck Institute for Developmental Biology, Max Planck Ring 5, 72076, Tübingen, Germany.
| | - Klaus Hantke
- IMIT, University of Tuebingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
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Goulas T, Garcia-Ferrer I, Marrero A, Marino-Puertas L, Duquerroy S, Gomis-Rüth FX. Structural and functional insight into pan-endopeptidase inhibition by α2-macroglobulins. Biol Chem 2017; 398:975-994. [PMID: 28253193 DOI: 10.1515/hsz-2016-0329] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/18/2017] [Indexed: 12/30/2022]
Abstract
Peptidases must be exquisitely regulated to prevent erroneous cleavage and one control is provided by protein inhibitors. These are usually specific for particular peptidases or families and sterically block the active-site cleft of target enzymes using lock-and-key mechanisms. In contrast, members of the +1400-residue multi-domain α2-macroglobulin inhibitor family (α2Ms) are directed against a broad spectrum of endopeptidases of disparate specificities and catalytic types, and they inhibit their targets without disturbing their active sites. This is achieved by irreversible trap mechanisms resulting from large conformational rearrangement upon cleavage in a promiscuous bait region through the prey endopeptidase. After decades of research, high-resolution structural details of these mechanisms have begun to emerge for tetrameric and monomeric α2Ms, which use 'Venus-flytrap' and 'snap-trap' mechanisms, respectively. In the former, represented by archetypal human α2M, inhibition is exerted through physical entrapment in a large cage, in which preys are still active against small substrates and inhibitors that can enter the cage through several apertures. In the latter, represented by a bacterial α2M from Escherichia coli, covalent linkage and steric hindrance of the prey inhibit activity, but only against very large substrates.
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Comprehensive Spatial Analysis of the Borrelia burgdorferi Lipoproteome Reveals a Compartmentalization Bias toward the Bacterial Surface. J Bacteriol 2017; 199:JB.00658-16. [PMID: 28069820 DOI: 10.1128/jb.00658-16] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/03/2017] [Indexed: 12/13/2022] Open
Abstract
The Lyme disease spirochete Borrelia burgdorferi is unique among bacteria in its large number of lipoproteins that are encoded by a small, exceptionally fragmented, and predominantly linear genome. Peripherally anchored in either the inner or outer membrane and facing either the periplasm or the external environment, these lipoproteins assume varied roles. A prominent subset of lipoproteins functioning as the apparent linchpins of the enzootic tick-vertebrate infection cycle have been explored as vaccine targets. Yet, most of the B. burgdorferi lipoproteome has remained uncharacterized. Here, we comprehensively and conclusively localize the B. burgdorferi lipoproteome by applying established protein localization assays to a newly generated epitope-tagged lipoprotein expression library and by validating the obtained individual protein localization results using a sensitive global mass spectrometry approach. The derived consensus localization data indicate that 86 of the 125 analyzed lipoproteins encoded by B. burgdorferi are secreted to the bacterial surface. Thirty-one of the remaining 39 periplasmic lipoproteins are retained in the inner membrane, with only 8 lipoproteins being anchored in the periplasmic leaflet of the outer membrane. The localization of 10 lipoproteins was further defined or revised, and 52 surface and 23 periplasmic lipoproteins were newly localized. Cross-referencing prior studies revealed that the borrelial surface lipoproteome contributing to the host-pathogen interface is encoded predominantly by plasmids. Conversely, periplasmic lipoproteins are encoded mainly by chromosomal loci. These studies close a gap in our understanding of the functional lipoproteome of an important human pathogen and set the stage for more in-depth studies of thus-far-neglected spirochetal lipoproteins.IMPORTANCE The small and exceptionally fragmented genome of the Lyme disease spirochete Borrelia burgdorferi encodes over 120 lipoproteins. Studies in the field have predominantly focused on a relatively small number of surface lipoproteins that play important roles in the transmission and pathogenesis of this global human pathogen. Yet, a comprehensive spatial assessment of the entire borrelial lipoproteome has been missing. The current study newly identifies 52 surface and 23 periplasmic lipoproteins. Overall, two-thirds of the B. burgdorferi lipoproteins localize to the surface, while outer membrane lipoproteins facing the periplasm are rare. This analysis underscores the dominant contribution of lipoproteins to the spirochete's rather complex and adaptable host-pathogen interface, and it encourages further functional exploration of its lipoproteome.
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Abstract
α2-macroglobulins are broad-spectrum endopeptidase inhibitors, which have to date been characterised from metazoans (vertebrates and invertebrates) and Gram-negative bacteria. Their structural and biochemical properties reveal two related modes of action: the "Venus flytrap" and the "snap-trap" mechanisms. In both cases, peptidases trigger a massive conformational rearrangement of α2-macroglobulin after cutting in a highly flexible bait region, which results in their entrapment. In some homologs, a second action takes place that involves a highly reactive β-cysteinyl-γ-glutamyl thioester bond, which covalently binds cleaving peptidases and thus contributes to the further stabilization of the enzyme:inhibitor complex. Trapped peptidases are still active, but have restricted access to their substrates due to steric hindrance. In this way, the human α2-macroglobulin homolog regulates proteolysis in complex biological processes, such as nutrition, signalling, and tissue remodelling, but also defends the host organism against attacks by external toxins and other virulence factors during infection and envenomation. In parallel, it participates in several other biological functions by modifying the activity of cytokines and regulating hormones, growth factors, lipid factors and other proteins, which has a great impact on physiology. Likewise, bacterial α2-macroglobulins may participate in defence by protecting cell wall components from attacking peptidases, or in host-pathogen interactions through recognition of host peptidases and/or antimicrobial peptides. α2-macroglobulins are more widespread than initially thought and exert multifunctional roles in both eukaryotes and prokaryotes, therefore, their on-going study is essential.
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Affiliation(s)
- Irene Garcia-Ferrer
- Proteolysis Lab, Structural Biology Unit, "María de Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain
- Present address: EMBL Grenoble, 71 Avenue des Martyrs; 38042 CS 90181, Grenoble Cedex 9, France
| | - Aniebrys Marrero
- Proteolysis Lab, Structural Biology Unit, "María de Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain
- Present address: Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - F Xavier Gomis-Rüth
- Proteolysis Lab, Structural Biology Unit, "María de Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain
| | - Theodoros Goulas
- Proteolysis Lab, Structural Biology Unit, "María de Maeztu" Unit of Excellence, Molecular Biology Institute of Barcelona (CSIC), Barcelona Science Park; c/Baldiri Reixac, 15-21, 08028, Barcelona, Spain.
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Matsumoto K, Hara H, Fishov I, Mileykovskaya E, Norris V. The membrane: transertion as an organizing principle in membrane heterogeneity. Front Microbiol 2015; 6:572. [PMID: 26124753 PMCID: PMC4464175 DOI: 10.3389/fmicb.2015.00572] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/25/2015] [Indexed: 01/05/2023] Open
Abstract
The bacterial membrane exhibits a significantly heterogeneous distribution of lipids and proteins. This heterogeneity results mainly from lipid-lipid, protein-protein, and lipid-protein associations which are orchestrated by the coupled transcription, translation and insertion of nascent proteins into and through membrane (transertion). Transertion is central not only to the individual assembly and disassembly of large physically linked groups of macromolecules (alias hyperstructures) but also to the interactions between these hyperstructures. We review here these interactions in the context of the processes in Bacillus subtilis and Escherichia coli of nutrient sensing, membrane synthesis, cytoskeletal dynamics, DNA replication, chromosome segregation, and cell division.
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Affiliation(s)
- Kouji Matsumoto
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, SaitamaJapan
| | - Hiroshi Hara
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, SaitamaJapan
| | - Itzhak Fishov
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-ShevaIsrael
| | - Eugenia Mileykovskaya
- Department of Biochemistry and Molecular Biology, University of Texas Medical School at HoustonHouston, TX, USA
| | - Vic Norris
- Laboratory of Microbiology Signals and Microenvironment EA 4312, Department of Science, University of Rouen, Mont-Saint-AignanFrance
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Kong Q, Nakai Y, Kuroda N, Shiratsuchi A, Nagaosa K, Nakanishi Y. Peptidoglycan recognition protein-triggered induction of Escherichia coli gene in Drosophila melanogaster. J Biochem 2015; 157:507-17. [DOI: 10.1093/jb/mvv002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 01/07/2015] [Indexed: 11/14/2022] Open
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Secretion of bacterial lipoproteins: through the cytoplasmic membrane, the periplasm and beyond. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1509-16. [PMID: 24780125 DOI: 10.1016/j.bbamcr.2014.04.022] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 04/16/2014] [Accepted: 04/18/2014] [Indexed: 11/20/2022]
Abstract
Bacterial lipoproteins are peripherally anchored membrane proteins that play a variety of roles in bacterial physiology and virulence in monoderm (single membrane-enveloped, e.g., gram-positive) and diderm (double membrane-enveloped, e.g., gram-negative) bacteria. After export of prolipoproteins through the cytoplasmic membrane, which occurs predominantly but not exclusively via the general secretory or Sec pathway, the proteins are lipid-modified at the cytoplasmic membrane in a multistep process that involves sequential modification of a cysteine residue and cleavage of the signal peptide by the signal II peptidase Lsp. In both monoderms and diderms, signal peptide processing is preceded by acylation with a diacylglycerol through preprolipoprotein diacylglycerol transferase (Lgt). In diderms but also some monoderms, lipoproteins are further modified with a third acyl chain through lipoprotein N-acyl transferase (Lnt). Fully modified lipoproteins that are destined to be anchored in the inner leaflet of the outer membrane (OM) are selected, transported and inserted by the Lol (lipoprotein outer membrane localization) pathway machinery, which consists of the inner-membrane (IM) ABC transporter-like LolCDE complex, the periplasmic LolA chaperone and the OM LolB lipoprotein receptor. Retention of lipoproteins in the cytoplasmic membrane results from Lol avoidance signals that were originally described as the "+2 rule". Surface localization of lipoproteins in diderms is rare in most bacteria, with the exception of several spirochetal species. Type 2 (T2SS) and type 5 (T5SS) secretion systems are involved in secretion of specific surface lipoproteins of γ-proteobacteria. In the model spirochete Borrelia burgdorferi, surface lipoprotein secretion does not follow established sorting rules, but remains dependent on N-terminal peptide sequences. Secretion through the outer membrane requires maintenance of lipoproteins in a translocation-competent unfolded conformation, likely through interaction with a periplasmic holding chaperone, which delivers the proteins to an outer membrane lipoprotein flippase. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey.
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Withman B, Gunasekera TS, Beesetty P, Agans R, Paliy O. Transcriptional responses of uropathogenic Escherichia coli to increased environmental osmolality caused by salt or urea. Infect Immun 2013; 81:80-9. [PMID: 23090957 PMCID: PMC3536127 DOI: 10.1128/iai.01049-12] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 10/11/2012] [Indexed: 12/30/2022] Open
Abstract
Uropathogenic Escherichia coli (UPEC) is the most common causative agent of urinary tract infections in humans. The majority of urinary infections develop via ascending route through the urethra, where bacterial cells come in contact with human urine prior to reaching the bladder or kidneys. Since urine contains significant amounts of inorganic ions and urea, it imposes osmotic and denaturing stresses on bacterial cells. In this study, we determined the transcriptional adaptive responses of UPEC strain CFT073 to the presence of 0.3 M NaCl or 0.6 M urea in the growth medium. The cell responses to these two osmolytes were drastically different. Although most of the genes of the osmotically inducible regulon were overexpressed in medium with salt, urea failed to stimulate osmotic stress response. At the same time, UPEC colonization genes encoding type 1 and F1C fimbriae and capsule biosynthesis were transcriptionally induced in the presence of urea but did not respond to increased salt concentration. We speculate that urea can potentially be sensed by uropathogenic bacteria to initiate infection program. In addition, several molecular chaperone genes were overexpressed in the presence of urea, whereas adding NaCl to the medium led to an upregulation of a number of anaerobic metabolism pathways.
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Affiliation(s)
- Benjamin Withman
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
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Nishimori JH, Newman TN, Oppong GO, Rapsinski GJ, Yen JH, Biesecker SG, Wilson RP, Butler BP, Winter MG, Tsolis RM, Ganea D, Tükel Ç. Microbial amyloids induce interleukin 17A (IL-17A) and IL-22 responses via Toll-like receptor 2 activation in the intestinal mucosa. Infect Immun 2012; 80:4398-408. [PMID: 23027540 PMCID: PMC3497426 DOI: 10.1128/iai.00911-12] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 09/25/2012] [Indexed: 12/16/2022] Open
Abstract
The Toll-like receptor 2 (TLR2)/TLR1 receptor complex responds to amyloid fibrils, a common component of biofilm material produced by members of the phyla Firmicutes, Bacteroidetes, and Proteobacteria. To determine whether this TLR2/TLR1 ligand stimulates inflammatory responses when bacteria enter intestinal tissue, we investigated whether expression of curli amyloid fibrils by the invasive enteric pathogen Salmonella enterica serotype Typhimurium contributes to T helper 1 and T helper 17 responses by measuring cytokine production in the mouse colitis model. A csgBA mutant, deficient in curli production, elicited decreased expression of interleukin 17A (IL-17A) and IL-22 in the cecal mucosa compared to the S. Typhimurium wild type. In TLR2-deficient mice, IL-17A and IL-22 expression was blunted during S. Typhimurium infection, suggesting that activation of the TLR2 signaling pathway contributes to the expression of these cytokines. T cells incubated with supernatants from bone marrow-derived dendritic cells (BMDCs) treated with curli fibrils released IL-17A in a TLR2-dependent manner in vitro. Lower levels of IL-6 and IL-23 production were detected in the supernatants of the TLR2-deficient BMDCs treated with curli fibrils. Consistent with this, three distinct T-cell populations-CD4(+) T helper cells, cytotoxic CD8(+) T cells, and γδ T cells-produced IL-17A in response to curli fibrils in the intestinal mucosa during S. Typhimurium infection. Notably, decreased IL-6 expression by the dendritic cells and decreased IL-23 expression by the dendritic cells and macrophages were observed in the cecal mucosa of mice infected with the curli mutant. We conclude that TLR2 recognition of bacterial amyloid fibrils in the intestinal mucosa represents a novel mechanism of immunoregulation, which contributes to the generation of inflammatory responses, including production of IL-17A and IL-22, in response to bacterial entry into the intestinal mucosa.
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Affiliation(s)
- Jessalyn H. Nishimori
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Tiffanny N. Newman
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Gertrude O. Oppong
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Glenn J. Rapsinski
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Jui-Hung Yen
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Steven G. Biesecker
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - R. Paul Wilson
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Brian P. Butler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Maria G. Winter
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Renee M. Tsolis
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Doina Ganea
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Çagla Tükel
- Department of Microbiology and Immunology, School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
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Yamane T, Enokida H, Hayami H, Kawahara M, Nakagawa M. Genome-wide transcriptome analysis of fluoroquinolone resistance in clinical isolates of Escherichia coli. Int J Urol 2011; 19:360-8. [PMID: 22211478 DOI: 10.1111/j.1442-2042.2011.02933.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVES Coincident with their worldwide use, resistance to fluoroquinolones in Escherichia coli has increased. To identify the gene expression profiles underlying fluoroquinolone resistance, we carried out genome-wide transcriptome analysis of fluoroquinolone-sensitive E. coli. METHODS Four fluoroquinolone-sensitive E. coli and five fluoroquinolone-resistant E. coli clinical isolates were subjected to complementary deoxyribonucleic acid microarray analysis. Some upregulated genes' expression was verified by real-time polymerase chain reaction using 104 E. coli clinical isolates, and minimum inhibitory concentration tests were carried out by using their transformants. RESULTS A total of 40 genes were significantly upregulated in fluoroquinolone-resistant E. coli isolates (P < 0.05). The expression of phage shock protein operons, which are involved in biofilm formation, was markedly upregulated in our profile of fluoroquinolone-resistant E. coli. One of the phage shock protein operons, pspC, was significantly upregulated in 50 fluoroquinolone-resistant E. coli isolates (P < 0.0001). The expression of type I fimbriae genes, which are pilus operons involved in biofilm formation, were markedly downregulated in fluoroquinolone-resistant E. coli. Deoxyribonucleic acid adenine methyltransferase (dam), which represses type I fimbriae genes, was significantly upregulated in the clinical fluoroquinolone-resistant E. coli isolates (P = 0.007). We established pspC- and dam-expressing E. coli transformants from fluoroquinolone-sensitive E. coli, and the minimum inhibitory concentration tests showed that the transformants acquired fluoroquinolone resistance, suggesting that upregulation of these genes contributes to acquiring fluoroquinolone resistance. CONCLUSIONS Upregulation of psp operones and dam underlying pilus operons downregulation might be associated with fluoroquinolone resistance in E. coli.
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Affiliation(s)
- Takashi Yamane
- Department of Urology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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15
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Characterizing the Escherichia coli O157:H7 proteome including protein associations with higher order assemblies. PLoS One 2011; 6:e26554. [PMID: 22087229 PMCID: PMC3210124 DOI: 10.1371/journal.pone.0026554] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Accepted: 09/28/2011] [Indexed: 11/19/2022] Open
Abstract
Background The recent outbreak of severe infections with Shiga toxin (Stx) producing Escherichia coli (STEC) serotype O104:H4 highlights the need to understand horizontal gene transfer among E. coli strains, identify novel virulence factors and elucidate their pathogenesis. Quantitative shotgun proteomics can contribute to such objectives, allowing insights into the part of the genome translated into proteins and the connectivity of biochemical pathways and higher order assemblies of proteins at the subcellular level. Methodology/Principal Findings We examined protein profiles in cell lysate fractions of STEC strain 86-24 (serotype O157:H7), following growth in cell culture or bacterial isolation from intestines of infected piglets, in the context of functionally and structurally characterized biochemical pathways of E. coli. Protein solubilization in the presence of Triton X-100, EDTA and high salt was followed by size exclusion chromatography into the approximate Mr ranges greater than 280 kDa, 280-80 kDa and 80-10 kDa. Peptide mixtures resulting from these and the insoluble fraction were analyzed by quantitative 2D-LC-nESI-MS/MS. Of the 2521 proteins identified at a 1% false discovery rate, representing 47% of all predicted E. coli O157:H7 gene products, the majority of integral membrane proteins were enriched in the high Mr fraction. Hundreds of proteins were enriched in a Mr range higher than that predicted for a monomer supporting their participation in protein complexes. The insoluble STEC fraction revealed enrichment of aggregation-prone proteins, including many that are part of large structure/function entities such as the ribosome, cytoskeleton and O-antigen biosynthesis cluster. Significance Nearly all E. coli O157:H7 proteins encoded by prophage regions were expressed at low abundance levels or not detected. Comparative quantitative analyses of proteins from distinct cell lysate fractions allowed us to associate uncharacterized proteins with membrane attachment, potential participation in stable protein complexes, and susceptibility to aggregation as part of larger structural assemblies.
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16
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Abstract
It has been known for many years that the small lipoprotein Lpp, which is the most abundant protein in E. coli, exists in two forms. The 'bound' form of the protein is tethered to the outer membrane (OM) by its N-terminal lipid moiety and covalently attached to the cell wall by its C-terminal lysine residue. The exact location of the 'free' form, however, has never been determined. In this issue of Molecular Microbiology, Cowles et al. demonstrate that the free form of Lpp is an integral OM protein whose C-terminus is exposed on the cell surface. The new study provides the first example of a lipoprotein that has a dual localization and adds to a growing body of evidence that lipoproteins can span the OM despite the lack of an obvious transmembrane segment. Furthermore, the new results raise intriguing questions about the assembly of both lipoproteins and other types of OM proteins.
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Affiliation(s)
- Harris D Bernstein
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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17
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Tükel C, Nishimori JH, Wilson RP, Winter MG, Keestra AM, van Putten JPM, Bäumler AJ. Toll-like receptors 1 and 2 cooperatively mediate immune responses to curli, a common amyloid from enterobacterial biofilms. Cell Microbiol 2010; 12:1495-505. [PMID: 20497180 DOI: 10.1111/j.1462-5822.2010.01485.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Responses to host amyloids and curli amyloid fibrils of Escherichia coli and Salmonella enterica serotype Typhimurium are mediated through Toll-like receptor (TLR) 2. Here we show that TLR2 alone was not sufficient for mediating responses to curli. Instead, transfection experiments with human cervical cancer (HeLa) cells and antibody-mediated inhibition of TLR signalling in human macrophage-like (THP-1) cells suggested that TLR2 interacts with TLR1 to recognize curli amyloid fibrils. TLR1/TLR2 also serves as a receptor for tri-acylated lipoproteins, which are produced by E. coli and other Gram-negative bacteria. Despite the presence of multiple TLR1/TLR2 ligands on intact bacterial cells, an inability to produce curli amyloid fibrils markedly reduced the ability of E. coli to induce TLR2-dependent responses in vitro and in vivo. Collectively, our data suggest that curli amyloid fibrils from enterobacterial biofilms significantly contribute to TLR1/TLR2-mediated host responses against intact bacterial cells.
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Affiliation(s)
- Cagla Tükel
- Temple University, School of Medicine, Department of Microbiology and Immunology, 3400N. Broad St. Kresge 502, Philadelphia, PA 19140, USA
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18
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Le Blastier S, Hamels A, Cabeen M, Schille L, Tilquin F, Dieu M, Raes M, Matroule JY. Phosphate starvation triggers production and secretion of an extracellular lipoprotein in Caulobacter crescentus. PLoS One 2010; 5:e14198. [PMID: 21152032 PMCID: PMC2996285 DOI: 10.1371/journal.pone.0014198] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 11/04/2010] [Indexed: 11/18/2022] Open
Abstract
Life in oligotrophic environments necessitates quick adaptive responses to a sudden lack of nutrients. Secretion of specific degradative enzymes into the extracellular medium is a means to mobilize the required nutrient from nearby sources. The aquatic bacterium Caulobacter crescentus must often face changes in its environment such as phosphate limitation. Evidence reported in this paper indicates that under phosphate starvation, C. crescentus produces a membrane surface-anchored lipoprotein named ElpS subsequently released into the extracellular medium. A complete set of 12 genes encoding a type II secretion system (T2SS) is located adjacent to the elpS locus in the C. crescentus genome. Deletion of this T2SS impairs release of ElpS in the environment, which surprisingly remains present at the cell surface, indicating that the T2SS is not involved in the translocation of ElpS to the outer membrane but rather in its release. Accordingly, treatment with protease inhibitors prevents release of ElpS in the extracellular medium suggesting that ElpS secretion relies on a T2SS-secreted protease. Finally, secretion of ElpS is associated with an increase in alkaline phosphatase activity in culture supernatants, suggesting a role of the secreted protein in inorganic phosphate mobilization. In conlusion, we have shown that upon phosphate starvation, C. crescentus produces an outer membrane bound lipoprotein, ElpS, which is further cleaved and released in the extracellular medium in a T2SS-dependent manner. Our data suggest that ElpS is associated with an alkaline phosphatase activity, thereby allowing the bacterium to gather inorganic phosphates from a poor environment.
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Affiliation(s)
- Sophie Le Blastier
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Aurore Hamels
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Matthew Cabeen
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut, United States of America
| | - Lionel Schille
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Françoise Tilquin
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
| | - Marc Dieu
- Unité de Recherche en Biologie Cellulaire, University of Namur, Namur, Belgium
| | - Martine Raes
- Unité de Recherche en Biologie Cellulaire, University of Namur, Namur, Belgium
| | - Jean-Yves Matroule
- Unité de Recherche en Biologie Moléculaire, University of Namur, Namur, Belgium
- * E-mail:
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19
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Contribution of proteomics toward solving the fascinating mysteries of the biogenesis of the envelope of Escherichia coli. Proteomics 2009; 10:771-84. [DOI: 10.1002/pmic.200900461] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Partridge JD, Bodenmiller DM, Humphrys MS, Spiro S. NsrR targets in the Escherichia coli genome: new insights into DNA sequence requirements for binding and a role for NsrR in the regulation of motility. Mol Microbiol 2009; 73:680-94. [PMID: 19656291 DOI: 10.1111/j.1365-2958.2009.06799.x] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Escherichia coli NsrR protein is a nitric oxide-sensitive repressor of transcription. The NsrR-binding site is predicted to comprise two copies of an 11 bp motif arranged as an inverted repeat with 1 bp spacing. By mutagenesis we confirmed that both 11 bp motifs are required for maximal NsrR repression of the ytfE promoter. We used chromatin immunoprecipitation and microarray analysis (ChIP-chip) to show that NsrR binds to 62 sites close to the 5' ends of genes. Analysis of the ChIP-chip data suggested that a single 11 bp motif (with the consensus sequence AANATGCATTT) can function as an NsrR-binding site in vivo. NsrR binds to sites in the promoter regions of the fliAZY, fliLMNOPQR and mqsR-ygiT transcription units, which encode proteins involved in motility and biofilm development. Reporter fusion assays confirmed that NsrR negatively regulates the fliA and fliL promoters. A mutation in the predicted 11 bp NsrR-binding site in the fliA promoter impaired repression by NsrR and prevented detectable binding in vivo. Assays on soft-agar confirmed that NsrR is a negative regulator of motility in E. coli K12 and in a uropathogenic strain; surface attachment assays revealed decreased levels of attached growth in the absence of NsrR.
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Affiliation(s)
- Jonathan D Partridge
- Department of Molecular and Cell Biology, The University of Texas at Dallas, Richardson, TX 75080, USA
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21
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Doan N, Gettins PGW. alpha-Macroglobulins are present in some gram-negative bacteria: characterization of the alpha2-macroglobulin from Escherichia coli. J Biol Chem 2008; 283:28747-56. [PMID: 18697741 DOI: 10.1074/jbc.m803127200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
alpha-Macroglobulins (alphaMs) are large glycoproteins that have been identified in a wide range of vertebrate and invertebrate species and are mostly thiol ester containing proteinase inhibitors. A recent analysis of bacterial genomes ( Budd, A., Blandin, S., Levashina, E. A., and Gibson, T. J. (2004) Genome Biol. 5, R38 ) identified many alpha-macroglobulin-like sequences that appear to have been acquired by Gram-negative bacteria from their metazoan hosts. We report the first expression and characterization of such a bacterial alpha-macroglobulin, that from Escherichia coli. This is also the first alpha-macroglobulin to be characterized that is predicted to be membrane-anchored. We found that the 183-kDa protein contains an intact thiol ester, is monomeric, and is localized to the periplasmic space. Reaction with proteinase results in limited cleavage within a bait region, rapid activation of the thiol ester, cross-linking to the attacking proteinase or other available nucleophiles, and partial protection of the proteinase against macromolecular substrates. Given these properties and the co-occurrence of the alphaM gene with one for a repair transglycosylase, this suggests a possible role for bacterial alphaMs in cell defense following host attack. Such a role would make bacterial alphaMs appropriate novel targets for antibiotic drugs.
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Affiliation(s)
- Ninh Doan
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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22
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Watanabe S, Oguchi Y, Yokota N, Tokuda H. Large-scale preparation of the homogeneous LolA lipoprotein complex and efficient in vitro transfer of lipoproteins to the outer membrane in a LolB-dependent manner. Protein Sci 2008; 16:2741-9. [PMID: 18029423 DOI: 10.1110/ps.073101307] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
An ATP-binding cassette transporter LolCDE complex of Escherichia coli releases lipoproteins destined to the outer membrane from the inner membrane as a complex with a periplasmic chaperone, LolA. Interaction of the LolA-lipoprotein complex with an outer membrane receptor, LolB, then causes localization of lipoproteins to the outer membrane. As far as examined, formation of the LolA-lipoprotein complex strictly depends on ATP hydrolysis by the LolCDE complex in the presence of LolA. It has been speculated, based on crystallographic and biochemical observations, that LolA undergoes an ATP-dependent conformational change upon lipoprotein binding. Thus, preparation of a large amount of the LolA-lipoprotein complex is difficult. Moreover, lipoproteins bound to LolA are heterogeneous. We report here that the coexpression of LolA and outer membrane-specific lipoprotein Pal from a very efficient plasmid causes the unusual accumulation of the LolA-Pal complex in the periplasm. The complex was purified to homogeneity and shown to be a functional intermediate of the lipoprotein localization pathway. In vitro incorporation of Pal into outer membranes revealed that a single molecule of LolB catalyzes the incorporation of more than 100 molecules of Pal into outer membranes. Moreover, the LolB-dependent incorporation of Pal was not affected by excess-free LolA, indicating that LolB specifically interacts with liganded LolA. Finally, the LolB depletion caused the accumulation of a significant amount of Pal in the periplasm, thereby establishing the conditions for preparation of the homogeneous LolA-lipoprotein complex.
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Affiliation(s)
- Shoji Watanabe
- Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo 113-0032, Japan
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23
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Faith JJ, Hayete B, Thaden JT, Mogno I, Wierzbowski J, Cottarel G, Kasif S, Collins JJ, Gardner TS. Large-scale mapping and validation of Escherichia coli transcriptional regulation from a compendium of expression profiles. PLoS Biol 2007; 5:e8. [PMID: 17214507 PMCID: PMC1764438 DOI: 10.1371/journal.pbio.0050008] [Citation(s) in RCA: 1013] [Impact Index Per Article: 56.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 11/07/2006] [Indexed: 11/19/2022] Open
Abstract
Machine learning approaches offer the potential to systematically identify transcriptional regulatory interactions from a compendium of microarray expression profiles. However, experimental validation of the performance of these methods at the genome scale has remained elusive. Here we assess the global performance of four existing classes of inference algorithms using 445 Escherichia coli Affymetrix arrays and 3,216 known E. coli regulatory interactions from RegulonDB. We also developed and applied the context likelihood of relatedness (CLR) algorithm, a novel extension of the relevance networks class of algorithms. CLR demonstrates an average precision gain of 36% relative to the next-best performing algorithm. At a 60% true positive rate, CLR identifies 1,079 regulatory interactions, of which 338 were in the previously known network and 741 were novel predictions. We tested the predicted interactions for three transcription factors with chromatin immunoprecipitation, confirming 21 novel interactions and verifying our RegulonDB-based performance estimates. CLR also identified a regulatory link providing central metabolic control of iron transport, which we confirmed with real-time quantitative PCR. The compendium of expression data compiled in this study, coupled with RegulonDB, provides a valuable model system for further improvement of network inference algorithms using experimental data.
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Affiliation(s)
- Jeremiah J Faith
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Boris Hayete
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
| | - Joshua T Thaden
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Ilaria Mogno
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- Department of Computer and Systems Science A. Ruberti, University of Rome, La Sapienza, Rome, Italy
| | - Jamey Wierzbowski
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- Cellicon Biotechnologies, Boston, Massachusetts, United States of America
| | - Guillaume Cottarel
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- Cellicon Biotechnologies, Boston, Massachusetts, United States of America
| | - Simon Kasif
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - James J Collins
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Timothy S Gardner
- Bioinformatics Program, Boston University, Boston, Massachusetts, United States of America
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
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24
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Matte A, Jia Z, Sunita S, Sivaraman J, Cygler M. Insights into the biology of Escherichia coli through structural proteomics. ACTA ACUST UNITED AC 2007; 8:45-55. [PMID: 17668295 DOI: 10.1007/s10969-007-9019-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Accepted: 06/28/2007] [Indexed: 10/23/2022]
Abstract
Escherichia coli has historically been an important organism for understanding a multitude of biological processes, and represents a model system as we attempt to simulate the workings of living cells. Many E. coli strains are also important human and animal pathogens for which new therapeutic strategies are required. For both reasons, a more complete and comprehensive understanding of the protein structure complement of E. coli is needed at the genome level. Here, we provide examples of insights into the mechanism and function of bacterial proteins that we have gained through the Bacterial Structural Genomics Initiative (BSGI), focused on medium-throughput structure determination of proteins from E. coli. We describe the structural characterization of several enzymes from the histidine biosynthetic pathway, the structures of three pseudouridine synthases, enzymes that synthesize one of the most abundant modified bases in RNA, as well as the combined use of protein structure and focused functional analysis to decipher functions for hypothetical proteins. Together, these results illustrate the power of structural genomics to contribute to a deeper biological understanding of bacterial processes.
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Affiliation(s)
- Allan Matte
- Biotechnology Research Institute, National Research Council Canada, Montreal, QC, Canada.
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25
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Serino L, Nesta B, Leuzzi R, Fontana MR, Monaci E, Mocca BT, Cartocci E, Masignani V, Jerse AE, Rappuoli R, Pizza M. Identification of a new OmpA-like protein in Neisseria gonorrhoeae involved in the binding to human epithelial cells and in vivo colonization. Mol Microbiol 2007; 64:1391-403. [PMID: 17542928 DOI: 10.1111/j.1365-2958.2007.05745.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Outer membrane protein As (OmpAs) are highly conserved proteins within the Enterobacteriaceae family. OmpA contributes to the maintenance of structural membrane integrity and invasion into mammalian cells. In Escherichia coli K1 OmpA also contributes to serum resistance and is involved in the virulence of the bacterium. Here we describe the identification of an OmpA-like protein in Neisseria gonorrhoeae (Ng-OmpA). We show that the gonococcal OmpA-like protein, similarly to E. coli OmpA, plays a significant role in the adhesion and invasion into human cervical carcinoma and endometrial cells and is required for entry into macrophages and intracellular survival. Furthermore, the isogenic knockout ompA mutant demonstrates reduced recovery in a mouse model of infection when compared with the wild-type strain, suggesting that Ng-OmpA plays an important role in the in vivo colonization. All together, these data suggest that the newly identified surface exposed protein Ng-OmpA represents a novel virulence factor of gonococcus.
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Affiliation(s)
- Laura Serino
- Research Centre, Novartis Vaccines, Via Fiorentina, 1, 53100 Siena, Italy.
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26
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Zhang N, Chen R, Young N, Wishart D, Winter P, Weiner JH, Li L. Comparison of SDS- and methanol-assisted protein solubilization and digestion methods forEscherichia colimembrane proteome analysis by 2-D LC-MS/MS. Proteomics 2007; 7:484-493. [PMID: 17309111 DOI: 10.1002/pmic.200600518] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Both organic solvent and surfactant have been used for dissolving membrane proteins for shotgun proteomics. In this work, two methods of protein solubilization, namely using 60% methanol or 1% SDS, to dissolve and analyze the inner membrane fraction of an Escherichia coli K12 cell lysate were compared. A total of 358 proteins (1417 unique peptides) from the methanol-solubilized protein mixture and 299 proteins (892 peptides) from the SDS-solubilized sample-were identified by using trypsin digestion and 2-D LC-ESI MS/MS. It was found that the methanol method detected more hydrophobic peptides, resulting in a greater number of proteins identified, than the SDS method. We found that 159 out of 358 proteins (44%) and 120 out of 299 proteins (40%) detected from the methanol- and SDS-solubilized samples, respectively, are integral membrane proteins. Among the 190 integral membrane proteins 70 were identified exclusively in the methanol-solubilized sample, 89 were identified by both methods, and only 31 proteins were exclusively identified by the SDS method. It is shown that the integral membrane proteins reflected the theoretical proteome for number of transmembrane helices, length, functional class, and topology, indicating there was no bias in the proteins identified.
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Affiliation(s)
- Nan Zhang
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Rui Chen
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Nelson Young
- Department of Biological Sciences and Computing Science, University of Alberta, Edmonton, Alberta, Canada
| | - David Wishart
- Department of Biological Sciences and Computing Science, University of Alberta, Edmonton, Alberta, Canada
| | - Philip Winter
- Institute for Biomolecular Design, University of Alberta, Edmonton, Alberta, Canada
| | - Joel H Weiner
- Institute for Biomolecular Design, University of Alberta, Edmonton, Alberta, Canada
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Liang Li
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
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27
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Rollins DK, Zhai D, Joe AL, Guidarelli JW, Murarka A, Gonzalez R. A novel data mining method to identify assay-specific signatures in functional genomic studies. BMC Bioinformatics 2006; 7:377. [PMID: 16907975 PMCID: PMC1599756 DOI: 10.1186/1471-2105-7-377] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2006] [Accepted: 08/14/2006] [Indexed: 11/25/2022] Open
Abstract
Background: The highly dimensional data produced by functional genomic (FG) studies makes it difficult to visualize relationships between gene products and experimental conditions (i.e., assays). Although dimensionality reduction methods such as principal component analysis (PCA) have been very useful, their application to identify assay-specific signatures has been limited by the lack of appropriate methodologies. This article proposes a new and powerful PCA-based method for the identification of assay-specific gene signatures in FG studies. Results: The proposed method (PM) is unique for several reasons. First, it is the only one, to our knowledge, that uses gene contribution, a product of the loading and expression level, to obtain assay signatures. The PM develops and exploits two types of assay-specific contribution plots, which are new to the application of PCA in the FG area. The first type plots the assay-specific gene contribution against the given order of the genes and reveals variations in distribution between assay-specific gene signatures as well as outliers within assay groups indicating the degree of importance of the most dominant genes. The second type plots the contribution of each gene in ascending or descending order against a constantly increasing index. This type of plots reveals assay-specific gene signatures defined by the inflection points in the curve. In addition, sharp regions within the signature define the genes that contribute the most to the signature. We proposed and used the curvature as an appropriate metric to characterize these sharp regions, thus identifying the subset of genes contributing the most to the signature. Finally, the PM uses the full dataset to determine the final gene signature, thus eliminating the chance of gene exclusion by poor screening in earlier steps. The strengths of the PM are demonstrated using a simulation study, and two studies of real DNA microarray data – a study of classification of human tissue samples and a study of E. coli cultures with different medium formulations. Conclusion We have developed a PCA-based method that effectively identifies assay-specific signatures in ranked groups of genes from the full data set in a more efficient and simplistic procedure than current approaches. Although this work demonstrates the ability of the PM to identify assay-specific signatures in DNA microarray experiments, this approach could be useful in areas such as proteomics and metabolomics.
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Affiliation(s)
- Derrick K Rollins
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
- Department of Statistics, Iowa State University, Ames, Iowa 50011, USA
| | - Dongmei Zhai
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
- Department of Statistics, Iowa State University, Ames, Iowa 50011, USA
| | - Alrica L Joe
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - Jack W Guidarelli
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
| | - Abhishek Murarka
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251-1892, USA
| | - Ramon Gonzalez
- Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa 50011, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77251-1892, USA
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28
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Plesa M, Hernalsteens JP, Vandenbussche G, Ruysschaert JM, Cornelis P. The SlyB outer membrane lipoprotein of Burkholderia multivorans contributes to membrane integrity. Res Microbiol 2006; 157:582-92. [PMID: 16500084 DOI: 10.1016/j.resmic.2005.11.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 11/22/2005] [Accepted: 11/29/2005] [Indexed: 11/24/2022]
Abstract
SlyB is a small lipoprotein of 158 amino acids which is conserved in different Gram-negative bacteria. In contrast to other bacteria, where slyB is monocistronic, in Burkholderia multivorans and in B. cenocepacia, slyB is the last gene of an operon comprising three open reading frames encoding a putative thiol peroxidase, a putative sugar kinase and SlyB. B. multivorans slyB mutants produced elongated cells and filaments which were never observed in cultures of wild-type or slyB-complemented cells. The slyB mutant also showed increased sensitivity to EDTA and SDS, and decreased siderophore production. Proteome analysis of a fraction enriched for membrane proteins suggested that SlyB, like the peptidoglycan-associated protein OpcL, is a major protein of the outer membrane. Taken together, these phenotypes suggest that SlyB contributes to the integrity of the cell envelope. By PCR amplification we were also able to demonstrate the conservation of slyB in all B. cepacia complex species tested.
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Affiliation(s)
- Maria Plesa
- Flanders Interuniversity Institute of Biotechnology (VIB6), Laboratory of Microbial Interactions, Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Building E, room 6.6, Pleinlaan 2, B-1050 Brussels, Belgium
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Watanabe S, Matsuyama SI, Tokuda H. Roles of the Hydrophobic Cavity and Lid of LolA in the Lipoprotein Transfer Reaction in Escherichia coli. J Biol Chem 2006; 281:3335-42. [PMID: 16354671 DOI: 10.1074/jbc.m509596200] [Citation(s) in RCA: 12] [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
LolA, a periplasmic chaperone, binds to outer membrane-specific lipoproteins released from the inner membrane through the action of an ATP-binding cassette transporter, LolCDE and then transfers them to the outer membrane receptor LolB, thereby mediating the inner to outer membrane transport of lipoproteins. The crystal structure of free LolA revealed that it has an internal hydrophobic cavity, which is surrounded by hydrophobic residues and closed by a lid comprising alpha-helices. The hydrophobic cavity most likely represents the binding site for the lipid moiety of a lipoprotein. It is speculated that the lid undergoes opening and closing upon the binding and transfer of lipoproteins, respectively. To determine the functions of the hydrophobic cavity and lid in detail, 14 residues involved in the formation of these structures were subjected to random mutagenesis. Among the obtained 21 LolA derivatives that did not support growth, 14 were active as to the binding of lipoproteins but defective in the transfer of lipoproteins to LolB, causing the periplasmic accumulation of a lipoprotein as a complex with a LolA derivative. A LolA derivative, I93G, bound lipoproteins faster than wild-type LolA did, whereas it did not transfer associated lipoproteins to LolB. When I93G and wild type LolA co-existed, lipoproteins were bound only to I93G; which therefore exhibited a dominant negative property. Another derivative, L59R, was also defective in the transfer of lipoproteins to LolB but did not exhibit a dominant negative property. Taken together, these results indicate that both the hydrophobic cavity and the lid are critically important for not only the binding of lipoproteins but also their transfer.
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Affiliation(s)
- Shoji Watanabe
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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30
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Zhang G, Brokx S, Weiner JH. Extracellular accumulation of recombinant proteins fused to the carrier protein YebF in Escherichia coli. Nat Biotechnol 2005; 24:100-4. [PMID: 16369539 DOI: 10.1038/nbt1174] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Accepted: 10/28/2005] [Indexed: 11/09/2022]
Abstract
Bacterial protein secretion is important in the life cycles of most bacteria, in which it contributes to the formation of pili and flagella and makes available extracellular enzymes to digest polymers for nutritional purposes and toxins to kill host cells in infections of humans, animals and plants. It is generally accepted that nonpathogenic laboratory strains of Escherichia coli, particularly K12 strains, do not secrete proteins into the extracellular medium under routine growth conditions. In this study, we report that commonly used laboratory strains secrete YebF, a small (10.8 kDa in the native form), soluble endogenous protein into the medium, challenging the status quo view that laboratory strains do not secrete proteins to the medium. We further show that 'passenger' proteins linked to the carboxyl end of YebF are efficiently secreted. The function of YebF is unknown, but its use as a carrier for transgenic proteins provides a tool to circumvent toxicity and other contamination issues associated with protein production in E. coli.
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Affiliation(s)
- Guijin Zhang
- Membrane Protein Research Group, Department of Biochemistry, 474 Medical Sciences Building, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
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Narita SI, Tokuda H. An ABC transporter mediating the membrane detachment of bacterial lipoproteins depending on their sorting signals. FEBS Lett 2005; 580:1164-70. [PMID: 16288742 DOI: 10.1016/j.febslet.2005.10.038] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 10/14/2005] [Accepted: 10/19/2005] [Indexed: 11/17/2022]
Abstract
Bacterial lipoproteins are anchored to membranes through a lipid moiety attached to the N-terminal Cys. Escherichia coli possesses more than 90 species of lipoproteins, most of which are localized in the outer membrane and others in the inner membrane. Sorting of lipoproteins to the outer membrane requires the Lol system comprising five Lol proteins. An ATP-binding cassette transporter, LolCDE, initiates the lipoprotein sorting by mediating the detachment of outer membrane-specific lipoproteins from the inner membrane. LolCDE does not recognize lipoproteins possessing Asp at position 2, which therefore remain anchored to the inner membrane. We will discuss the mechanism of LolCDE based on data obtained through in vitro experiments.
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Affiliation(s)
- Shin-ichiro Narita
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Tokyo 113-0032, Japan
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Taniguchi N, Matsuyama SI, Tokuda H. Mechanisms Underlying Energy-independent Transfer of Lipoproteins from LolA to LolB, Which Have Similar Unclosed β-Barrel Structures. J Biol Chem 2005; 280:34481-8. [PMID: 16091355 DOI: 10.1074/jbc.m507388200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Lol system, comprising five Lol proteins, transfers lipoproteins from the inner to the outer membrane of Escherichia coli. Periplasmic LolA accepts lipoproteins from LolCDE in the inner membrane and immediately transfers them to LolB, a receptor anchored to the outer membrane. The unclosed beta-barrel structures of LolA and LolB are very similar to each other and form hydrophobic cavities for lipoproteins. The lipoprotein transfer between these similar structures is unidirectional and very efficient, but requires no energy input. To reveal the mechanisms underlying this lipoprotein transfer, Arg and Phe at positions 43 and 47, respectively, of LolA were systematically mutagenized. The two residues were previously found to affect abilities to accept and transfer lipoproteins. Substitution of Phe-47 with polar residues inhibited the ability to accept lipoproteins from the inner membrane. No derivatives caused periplasmic accumulation of lipoproteins. In contrast, many Arg-43 derivatives caused unusual periplasmic accumulation of lipoproteins to various extents. However, all derivatives, except one having Leu instead of Arg, supported the growth of cells. All Arg-43 derivatives retained the ability to accept lipoproteins from the inner membrane, whereas their abilities to transfer associated lipoproteins to LolB were variously reduced. Assessment of the intensity of the hydrophobic interaction between lipoproteins and Arg-43 derivatives revealed that the LolA-lipoprotein interaction should be weak, otherwise lipoprotein transfer to LolB is inhibited, causing accumulation of lipoproteins in the periplasm.
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Affiliation(s)
- Naohiro Taniguchi
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032
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Egler M, Grosse C, Grass G, Nies DH. Role of the extracytoplasmic function protein family sigma factor RpoE in metal resistance of Escherichia coli. J Bacteriol 2005; 187:2297-307. [PMID: 15774872 PMCID: PMC1065229 DOI: 10.1128/jb.187.7.2297-2307.2005] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RpoE of Escherichia coli is a sigma factor of the extracytoplasmic function protein family and is required for the expression of proteins involved in maintaining the integrity of periplasmic and outer membrane components. RpoE of E. coli was needed for full resistance to Zn(II), Cd(II), and Cu(II). Promoter gene fusion and quantitative real time reverse transcription (RT)-PCR (qRT-PCR) assays demonstrated that expression of RpoE was induced by metals. Global gene expression profiles upon metal treatment of a DeltarpoE mutant strain and its wild-type strain were analyzed with microarrays, and selected genes were confirmed by qRT-PCR. The absolute number of genes that were changed in their expression upon metal stress was similar in both strains, but the increase or decrease in transcript levels upon metal treatment was smaller in the DeltarpoE mutant strain than in the wild type. Genes showing increased expression in the DeltarpoE mutant strain encoded proteins that belong to general defense systems against protein-denaturing agents. Genes showing decreased expression were part of the RpoE modulon itself plus the ompC gene, encoding a major outer membrane protein. A DeltaompC deletion strain was as sensitive to Cu(II) and Cd(II) as the DeltarpoE mutant or a DeltarpoE DeltaompC double mutant strain. In the case of Zn(II), the double mutant was more sensitive than either single mutant. This indicates that increased expression of OmpC contributes to the RpoE modulon-mediated response to metals.
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Affiliation(s)
- Monique Egler
- Institut für Mikrobiologie, Kurt-Mothes-Str. 3, 06099 Halle, Germany
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Miyadai H, Tanaka-Masuda K, Matsuyama SI, Tokuda H. Effects of Lipoprotein Overproduction on the Induction of DegP (HtrA) Involved in Quality Control in the Escherichia coli Periplasm. J Biol Chem 2004; 279:39807-13. [PMID: 15252048 DOI: 10.1074/jbc.m406390200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent biochemical examination has revealed the presence of at least 90 different lipoproteins in Escherichia coli. Among previously identified lipoproteins, only an outer membrane lipoprotein, NlpE, is known to induce expression of the degP gene upon its overproduction. The degP gene encodes a periplasmic protease, which is thought to be involved in the digestion of unfolded proteins, and is essential for growth at high temperatures. However, it is not completely clear why NlpE overproduction causes degP expression. Moreover, among newly confirmed lipoproteins, there may be others that also induce degP expression. Therefore, we overproduced each of the 90 lipoproteins and examined the level of degP expression as beta-galactosidase activity by using a degP promoter-lacZ fusion. The extent of degP expression caused by NlpE overproduction was dependent on the mode of degP-lacZ fusion. On the other hand, new inner membrane lipoprotein YafY strongly induced degP expression irrespective of the mode of fusion even though the level of overproduced YafY was lower than that of NlpE. The induction of degP expression by YafY overproduction was dependent on the Cpx two-component system. Alteration of the lipoprotein-sorting signals of NlpE and YafY did not abolish the degP induction. However, a YafY derivative possessing the outer membrane signal remained on inner membranes. The non-lipidated derivative of NlpE did not induce degP expression, indicating that membrane anchoring is essential for degP induction. The amino acid sequences of YafY and YfjS, another inner membrane lipoprotein, are highly identical, but overproduction of the latter did not induce degP expression. Construction of various YafY-YfjS chimeric lipoproteins revealed that only a few residues located in the N- and C-terminal regions were important for the induction of DegP.
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Affiliation(s)
- Hidenori Miyadai
- Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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35
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Current Awareness on Comparative and Functional Genomics. Comp Funct Genomics 2004. [PMCID: PMC2447475 DOI: 10.1002/cfg.357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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