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Castillo-Polo JA, Hernández-García M, Maruri-Aransolo A, de la Vega C, Ruiz-Garbajosa P, Cantón R. Evolution of ceftazidime-avibactam and cefiderocol resistance in ST131-H30R1- Escherichia coli isolates with KPC-3 mutants and application of FTIR biotyping. Microbiol Spectr 2024; 12:e0277623. [PMID: 38415657 PMCID: PMC10986490 DOI: 10.1128/spectrum.02776-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 02/14/2024] [Indexed: 02/29/2024] Open
Abstract
Ceftazidime-avibactam and cefiderocol represent two of the few alternatives for infections by KPC-producing Enterobacterales. We reported the emergence of resistance to both ceftazidime-avibactam and cefiderocol in a KPC-producing ST131-Escherichia coli (KPC-ST131-Ec) clinical isolate. Antimicrobial susceptibility testing, Fourier-transform infrared (FTIR) spectroscopy, whole-genome sequencing, and cloning experiments were performed. A KPC-49-Ec isolate resistant to ceftazidime-avibactam (MICCZA > 16/4 mg/L) and susceptible to cefiderocol (MICFDC: 2 mg/L) was recovered in a blood sample from an oncologic patient hospitalized in the medical ICU (June 2019) during ceftazidime-avibactam treatment. After 44 days, a KPC-31-Ec resistant to both ceftazidime-avibactam and cefiderocol (MICCZA > 16/4 mg/L, MICFDC: 8 mg/L) was found in a rectal sample during a second cycle of ceftazidime-avibactam treatment. Both KPC-49 (R163S) and KPC-31 (D179Y) were detected in the epidemic ST131-H30R1-Ec high-risk clone and showed a phenotype resembling that of ESBL producers. FTIR spectroscopy managed to differentiate cefiderocol-susceptible and resistant ST131-Ec isolates, and these from others belonging to different clones. After cloning and transformation experiments, KPC-49 and KPC-31 were responsible for ceftazidime-avibactam resistance (MICCZA > 16/4 mg/L) and decreased carbapenem MICs (MICMER ≤ 0.12 mg/L, MICIMI ≤ 1 mg/L). KPC-31 was also shown to be associated with increased MICs of cefiderocol (twofold and threefold dilutions over KPC-3 and KPC-49, respectively). However, mutations in proteins participating in outer membrane stability and integrity, such as TolR, could have a more relevant role in cefiderocol resistance. The effects of ceftazidime-avibactam and cefiderocol co-resistance in clinical isolates of Enterobacterales producing KPC mutants make their identification challenging for clinical laboratories.IMPORTANCEThroughout four admissions in our hospital of a single patient, different KPC-3 variants (KPC-3, KPC-49, and KPC-31) were found in surveillance and clinical ST131-Escherichia coli isolates, after prolonged therapies with meropenem and ceftazidime-avibactam. Different patterns of resistance to cefiderocol and ceftazidime-avibactam emerged, accompanied by restored carbapenem susceptibility. The inability to detect these variants with some phenotypic methods, especially KPC-31 by immunochromatography, and the expression of a phenotype similar to that of ESBL producers, posed challenge to identify these variants in the clinical microbiology laboratory. Molecular methods and whole-genome sequencing are necessary and new techniques able to cluster or differentiate related isolates could also be helpful; this is the case of Fourier-transform infrared spectroscopy, which managed in our study to discriminate isolates by cefiderocol susceptibility within ST131, and those from the non-ST131 ones.
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Affiliation(s)
- Juan Antonio Castillo-Polo
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Marta Hernández-García
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Ainhize Maruri-Aransolo
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Carmen de la Vega
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
| | - Patricia Ruiz-Garbajosa
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
| | - Rafael Cantón
- Servicio de Microbiología, Hospital Universitario Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, Madrid, Spain
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Williams-Jones DP, Webby MN, Press CE, Gradon JM, Armstrong SR, Szczepaniak J, Kleanthous C. Tunable force transduction through the Escherichia coli cell envelope. Proc Natl Acad Sci U S A 2023; 120:e2306707120. [PMID: 37972066 PMCID: PMC10666116 DOI: 10.1073/pnas.2306707120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 09/28/2023] [Indexed: 11/19/2023] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria is not energised and so processes requiring a driving force must connect to energy-transduction systems in the inner membrane (IM). Tol (Tol-Pal) and Ton are related, proton motive force- (PMF-) coupled assemblies that stabilise the OM and import essential nutrients, respectively. Both rely on proton-harvesting IM motor (stator) complexes, which are homologues of the flagellar stator unit Mot, to transduce force to the OM through elongated IM force transducer proteins, TolA and TonB, respectively. How PMF-driven motors in the IM generate mechanical work at the OM via force transducers is unknown. Here, using cryoelectron microscopy, we report the 4.3Å structure of the Escherichia coli TolQR motor complex. The structure reaffirms the 5:2 stoichiometry seen in Ton and Mot and, with motor subunits related to each other by 10 to 16° rotation, supports rotary motion as the default for these complexes. We probed the mechanism of force transduction to the OM through in vivo assays of chimeric TolA/TonB proteins where sections of their structurally divergent, periplasm-spanning domains were swapped or replaced by an intrinsically disordered sequence. We find that TolA mutants exhibit a spectrum of force output, which is reflected in their respective abilities to both stabilise the OM and import cytotoxic colicins across the OM. Our studies demonstrate that structural rigidity of force transducer proteins, rather than any particular structural form, drives the efficient conversion of PMF-driven rotary motions of 5:2 motor complexes into physiologically relevant force at the OM.
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Affiliation(s)
| | - Melissa N. Webby
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Cara E. Press
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Jan M. Gradon
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Sophie R. Armstrong
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Joanna Szczepaniak
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
| | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, OxfordOX1 3QU, United Kingdom
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3
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Zeng X, Hinenoya A, Guan Z, Xu F, Lin J. Critical role of the RpoE stress response pathway in polymyxin resistance of Escherichia coli. J Antimicrob Chemother 2023; 78:732-746. [PMID: 36658759 PMCID: PMC10396327 DOI: 10.1093/jac/dkad003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/31/2022] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVES Polymyxins, including colistin, are the drugs of last resort to treat MDR bacterial infections in humans. In-depth understanding of the molecular basis and regulation of polymyxin resistance would provide new therapeutic opportunities to combat increasing polymyxin resistance. Here we aimed to identify novel targets that are crucial for polymyxin resistance using Escherichia coli BL21(DE3), a unique colistin-resistant model strain. METHODS BL21(DE3) was subjected to random transposon mutagenesis for screening colistin-susceptible mutants. The insertion sites of desired mutants were mapped; the key genes of interest were also inactivated in different strains to examine functional conservation. Specific genes in the known PmrAB and PhoPQ regulatory network were inactivated to examine crosstalk among different pathways. Lipid A species and membrane phospholipids were analysed by normal phase LC/MS. RESULTS Among eight mutants with increased susceptibility to colistin, five mutants contained different mutations in three genes (rseP, degS and surA) that belong to the RpoE stress response pathway. Inactivation of rpoE, pmrB, eptA or pmrD led to significantly increased susceptibility to colistin; however, inactivation of phoQ or eptB did not change colistin MIC. RpoE mutation in different E. coli and Salmonella resistant strains all led to significant reduction in colistin MIC (16-32-fold). Inactivation of rpoE did not change the lipid A profile but significantly altered the phospholipid profile. CONCLUSIONS Inactivation of the important members of the RpoE regulon in polymyxin-resistant strains led to a drastic reduction in polymyxin MIC and an increase of lysophospholipids with no change in lipid A modifications.
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Affiliation(s)
- Ximin Zeng
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA
| | - Atsushi Hinenoya
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA
- Graduate School of Veterinary Science, Osaka Metropolitan University, Osaka, Japan
- Asian Health Science Research Institute, Osaka Metropolitan University, Osaka, Japan
- Osaka International Research Center for Infectious Diseases, Osaka Metropolitan University, Osaka, Japan
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - Fuzhou Xu
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA
- Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Jun Lin
- Department of Animal Science, The University of Tennessee, Knoxville, TN, USA
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Biou V, Adaixo RJD, Chami M, Coureux PD, Laurent B, Enguéné VYN, de Amorim GC, Izadi-Pruneyre N, Malosse C, Chamot-Rooke J, Stahlberg H, Delepelaire P. Structural and molecular determinants for the interaction of ExbB from Serratia marcescens and HasB, a TonB paralog. Commun Biol 2022; 5:355. [PMID: 35418619 PMCID: PMC9008036 DOI: 10.1038/s42003-022-03306-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 03/22/2022] [Indexed: 01/20/2023] Open
Abstract
ExbB and ExbD are cytoplasmic membrane proteins that associate with TonB to convey the energy of the proton-motive force to outer membrane receptors in Gram-negative bacteria for iron uptake. The opportunistic pathogen Serratia marcescens (Sm) possesses both TonB and a heme-specific TonB paralog, HasB. ExbBSm has a long periplasmic extension absent in other bacteria such as E. coli (Ec). Long ExbB's are found in several genera of Alphaproteobacteria, most often in correlation with a hasB gene. We investigated specificity determinants of ExbBSm and HasB. We determined the cryo-EM structures of ExbBSm and of the ExbB-ExbDSm complex from S. marcescens. ExbBSm alone is a stable pentamer, and its complex includes two ExbD monomers. We showed that ExbBSm extension interacts with HasB and is involved in heme acquisition and we identified key residues in the membrane domain of ExbBSm and ExbBEc, essential for function and likely involved in the interaction with TonB/HasB. Our results shed light on the class of inner membrane energy machinery formed by ExbB, ExbD and HasB.
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Affiliation(s)
- Valérie Biou
- grid.508487.60000 0004 7885 7602Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, UMR 7099 CNRS, F-75005 Paris, France ,grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Ricardo Jorge Diogo Adaixo
- grid.6612.30000 0004 1937 0642Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Mohamed Chami
- grid.6612.30000 0004 1937 0642Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Pierre-Damien Coureux
- grid.10877.390000000121581279Laboratoire de Biologie Structurale de la Cellule, BIOC, UMR7654 CNRS/Ecole polytechnique, Palaiseau, France
| | - Benoist Laurent
- grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France ,grid.508487.60000 0004 7885 7602Plateforme de Bioinformatique, Université de Paris, FRC 550 CNRS, F-75005 Paris, France
| | - Véronique Yvette Ntsogo Enguéné
- grid.508487.60000 0004 7885 7602Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, UMR 7099 CNRS, F-75005 Paris, France ,grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France ,grid.5335.00000000121885934Present Address: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA UK
| | - Gisele Cardoso de Amorim
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS, USR3756 Paris, France ,grid.8536.80000 0001 2294 473XPresent Address: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ Brasil
| | - Nadia Izadi-Pruneyre
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS, USR3756 Paris, France
| | - Christian Malosse
- grid.428999.70000 0001 2353 6535Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut Pasteur, 75015 Paris, France
| | - Julia Chamot-Rooke
- grid.428999.70000 0001 2353 6535Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut Pasteur, 75015 Paris, France
| | - Henning Stahlberg
- grid.6612.30000 0004 1937 0642Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland ,grid.9851.50000 0001 2165 4204Present Address: Centre d’imagerie Dubochet UNIL-EPFL-UNIGE & Laboratoire de microscopie électronique biologique UNIL-EPFL, Lausanne, Switzerland
| | - Philippe Delepelaire
- grid.508487.60000 0004 7885 7602Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, UMR 7099 CNRS, F-75005 Paris, France ,grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France
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Yeow J, Chng SS. Of zones, bridges and chaperones - phospholipid transport in bacterial outer membrane assembly and homeostasis. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35384832 DOI: 10.1099/mic.0.001177] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The outer membrane (OM) is a formidable permeability barrier that protects Gram-negative bacteria from detergents and antibiotics. It possesses exquisite lipid asymmetry, requiring the placement and retention of lipopolysaccharides (LPS) in the outer leaflet, and phospholipids (PLs) in the inner leaflet. To establish OM lipid asymmetry, LPS are transported from the inner membrane (IM) directly to the outer leaflet of the OM. In contrast, mechanisms for PL trafficking across the cell envelope are much less understood. In this review, we summarize and discuss recent advances in our understanding of PL transport, making parallel comparisons to well-established pathways for OM lipoprotein (Lol) and LPS (Lpt). Insights into putative PL transport systems highlight possible connections back to the 'Bayer bridges', adhesion zones between the IM and the OM that had been observed more than 50 years ago, and proposed as passages for export of OM components, including LPS and PLs.
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Affiliation(s)
- Jiang Yeow
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
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6
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Abstract
The Ton complex is a molecular motor at the inner membrane of Gram-negative bacteria that uses a proton gradient to apply forces on outer membrane (OM) proteins to permit active transport of nutrients into the periplasmic space. Recently, the structure of the ExbB–ExbD subcomplex was determined in several bacterial species, but the complete structure and stoichiometry of TonB have yet to be determined. The C-terminal end of TonB is known to cross the periplasm and interact with TonB-dependent outer membrane transport proteins with high affinity. Yet despite having significant knowledge of these transport proteins, it is not clear how the Ton motor opens a pathway across the outer membrane for nutrient import. Additionally, the mechanism by which energy is harnessed from the inner membrane subcomplex and transduced to the outer membrane via TonB is not well understood. In this review, we will discuss the gaps in the knowledge about the complete structure of the Ton motor complex and the relationship between ion flow used to generate mechanical work at the outer membrane and the nutrient transport process.
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Roles of the Tol/Pal System in Bacterial Pathogenesis and Its Application to Antibacterial Therapy. Vaccines (Basel) 2022; 10:vaccines10030422. [PMID: 35335056 PMCID: PMC8953051 DOI: 10.3390/vaccines10030422] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 01/27/2023] Open
Abstract
The Tol/Pal system (also written as “The Tol-Pal system”) is a set of protein complexes produced by most Gram-negative bacteria. It comprises the inner membrane-associated and the outer membrane-anchored subunits composed of the TolA, TolQ, and TolR proteins and the TolB and Pal proteins, respectively. Although the Tol/Pal system was first defined as bacterial proteins involved in colicin uptake of Escherichia coli, its global roles have been characterized in several studies as mentioned in this article. Pathogenesis of many Gram-negative pathogens is sustained by the Tol/Pal system. It is also essential for cell growth and fitness in some pathogens. Therefore, the Tol/Pal system is proposed as a potential target for antimicrobial chemotherapy. Although the tol/pal mutants are low in virulence, they still have the ability to stimulate the immune system. The Pal protein is highly immunogenic and induces both adaptive and innate immune responses. Therefore, the tol/pal mutant strains and Pal proteins also have potential vaccine properties. For these reasons, the Tol/Pal system represents a promising research target in the development of antibacterial therapeutic strategies for refractory infections caused by multi-drug-resistant (MDR), Gram-negative pathogens. In this paper, we summarize studies on the Tol/Pal system associated with bacterial pathogenesis and vaccine development.
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Webby MN, Williams-Jones DP, Press C, Kleanthous C. Force-Generation by the Trans-Envelope Tol-Pal System. Front Microbiol 2022; 13:852176. [PMID: 35308353 PMCID: PMC8928145 DOI: 10.3389/fmicb.2022.852176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 11/13/2022] Open
Abstract
The Tol-Pal system spans the cell envelope of Gram-negative bacteria, transducing the potential energy of the proton motive force (PMF) into dissociation of the TolB-Pal complex at the outer membrane (OM), freeing the lipoprotein Pal to bind the cell wall. The primary physiological role of Tol-Pal is to maintain OM integrity during cell division through accumulation of Pal molecules at division septa. How the protein complex couples the PMF at the inner membrane into work at the OM is unknown. The effectiveness of this trans-envelope energy transduction system is underscored by the fact that bacteriocins and bacteriophages co-opt Tol-Pal as part of their import/infection mechanisms. Mechanistic understanding of this process has been hindered by a lack of structural data for the inner membrane TolQ-TolR stator, of its complexes with peptidoglycan (PG) and TolA, and of how these elements combined power events at the OM. Recent studies on the homologous stators of Ton and Mot provide a starting point for understanding how Tol-Pal works. Here, we combine ab initio protein modeling with previous structural data on sub-complexes of Tol-Pal as well as mutagenesis, crosslinking, co-conservation analysis and functional data. Through this composite pooling of in silico, in vitro, and in vivo data, we propose a mechanism for force generation in which PMF-driven rotary motion within the stator drives conformational transitions within a long TolA helical hairpin domain, enabling it to reach the TolB-Pal complex at the OM.
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Affiliation(s)
| | | | | | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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Vincent MS, Comas Hervada C, Sebban-Kreuzer C, Le Guenno H, Chabalier M, Kosta A, Guerlesquin F, Mignot T, McBride MJ, Cascales E, Doan T. Dynamic proton-dependent motors power type IX secretion and gliding motility in Flavobacterium. PLoS Biol 2022; 20:e3001443. [PMID: 35333857 PMCID: PMC8986121 DOI: 10.1371/journal.pbio.3001443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/06/2022] [Accepted: 03/01/2022] [Indexed: 02/06/2023] Open
Abstract
Motile bacteria usually rely on external apparatus like flagella for swimming or pili for twitching. By contrast, gliding bacteria do not rely on obvious surface appendages to move on solid surfaces. Flavobacterium johnsoniae and other bacteria in the Bacteroidetes phylum use adhesins whose movement on the cell surface supports motility. In F. johnsoniae, secretion and helicoidal motion of the main adhesin SprB are intimately linked and depend on the type IX secretion system (T9SS). Both processes necessitate the proton motive force (PMF), which is thought to fuel a molecular motor that comprises the GldL and GldM cytoplasmic membrane proteins. Here, we show that F. johnsoniae gliding motility is powered by the pH gradient component of the PMF. We further delineate the interaction network between the GldLM transmembrane helices (TMHs) and show that conserved glutamate residues in GldL TMH2 are essential for gliding motility, although having distinct roles in SprB secretion and motion. We then demonstrate that the PMF and GldL trigger conformational changes in the GldM periplasmic domain. We finally show that multiple GldLM complexes are distributed in the membrane, suggesting that a network of motors may be present to move SprB along a helical path on the cell surface. Altogether, our results provide evidence that GldL and GldM assemble dynamic membrane channels that use the proton gradient to power both T9SS-dependent secretion of SprB and its motion at the cell surface. Motile bacteria usually rely on external apparatus like flagella or pili, but gliding bacteria do not rely on obvious surface appendages for their movement. This study shows that bacteria in the phylum Bacteroidetes use proton-dependent motors to power protein secretion and gliding motility.
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Affiliation(s)
- Maxence S. Vincent
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Caterina Comas Hervada
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Corinne Sebban-Kreuzer
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Hugo Le Guenno
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Maïalène Chabalier
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Artemis Kosta
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Françoise Guerlesquin
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7283, Marseille, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Eric Cascales
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
- * E-mail: (EC); (TD)
| | - Thierry Doan
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
- * E-mail: (EC); (TD)
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10
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Thoma J, Burmann BM. Architects of their own environment: How membrane proteins shape the Gram-negative cell envelope. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2021; 128:1-34. [PMID: 35034716 DOI: 10.1016/bs.apcsb.2021.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Gram-negative bacteria are surrounded by a complex multilayered cell envelope, consisting of an inner and an outer membrane, and separated by the aqueous periplasm, which contains a thin peptidoglycan cell wall. These bacteria employ an arsenal of highly specialized membrane protein machineries to ensure the correct assembly and maintenance of the membranes forming the cell envelope. Here, we review the diverse protein systems, which perform these functions in Escherichia coli, such as the folding and insertion of membrane proteins, the transport of lipoproteins and lipopolysaccharide within the cell envelope, the targeting of phospholipids, and the regulation of mistargeted envelope components. Some of these protein machineries have been known for a long time, yet still hold surprises. Others have only recently been described and some are still missing pieces or yet remain to be discovered.
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Affiliation(s)
- Johannes Thoma
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden; Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
| | - Björn M Burmann
- Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Göteborg, Sweden; Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
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11
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Recruitment of the TolA protein to cell constriction sites in Escherichia coli via three separate mechanisms, and a critical role for FtsWI activity in recruitment of both TolA and TolQ. J Bacteriol 2021; 204:e0046421. [PMID: 34748387 DOI: 10.1128/jb.00464-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The Tol-Pal system of Gram-negative bacteria helps maintain integrity of the cell envelope and ensures that invagination of the envelope layers during cell fission occurs in a well-coordinated manner. In E. coli, the five Tol-Pal proteins (TolQ, R, A, B and Pal) accumulate at cell constriction sites in a manner that normally requires the activity of the cell constriction initiation protein FtsN. While septal recruitment of TolR, TolB and Pal also requires the presence of TolQ and/or TolA, each of the the latter two can recognize constriction sites independently of the other system proteins. What attracts TolQ or TolA to these sites is unclear. We show that FtsN attracts both proteins in an indirect fashion, and that PBP1A, PBP1B and CpoB are dispensable for their septal recruitment. However, the β-lactam aztreonam readily interferes with septal accumulation of both TolQ and TolA, indicating that FtsN-stimulated production of septal peptidoglycan by the FtsWI synthase is critical to their recruitment. We also discovered that each of TolA's three domains can recognize division sites in a separate fashion. Notably, the middle domain (TolAII) is responsible for directing TolA to constriction sites in the absence of other Tol-Pal proteins and CpoB, while recruitment of TolAI and TolAIII requires TolQ and a combination of TolB, Pal, and CpoB, respectively. Additionally, we describe the construction and use of functional fluorescent sandwich fusions of the ZipA division protein, which should be more broadly valuable in future studies of the E. coli cell division machinery. IMPORTANCE Cell division (cytokinesis) is a fundamental biological process that is incompletely understood for any organism. Division of bacterial cells relies on a ring-like machinery called the septal ring or divisome that assembles along the circumference of the mother cell at the site where constriction will eventually occur. In the well-studied bacterium Escherichia coli, this machinery contains over thirty distinct proteins. We studied how two such proteins, TolA and TolQ, which also play a role in maintaining integrity of the outer-membrane, are recruited to the machinery. We find that TolA can be recruited by three separate mechanisms, and that both proteins rely on the activity of a well-studied cell division enzyme for their recruitment.
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12
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Szczepaniak J, Press C, Kleanthous C. The multifarious roles of Tol-Pal in Gram-negative bacteria. FEMS Microbiol Rev 2021; 44:490-506. [PMID: 32472934 PMCID: PMC7391070 DOI: 10.1093/femsre/fuaa018] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022] Open
Abstract
In the 1960s several groups reported the isolation and preliminary genetic mapping of
Escherichia coli strains tolerant towards the
action of colicins. These pioneering studies kick-started two new fields in bacteriology;
one centred on how bacteriocins like colicins exploit the Tol (or more commonly Tol-Pal)
system to kill bacteria, the other on the physiological role of this cell
envelope-spanning assembly. The following half century has seen significant advances in
the first of these fields whereas the second has remained elusive, until recently. Here,
we review work that begins to shed light on Tol-Pal function in Gram-negative bacteria.
What emerges from these studies is that Tol-Pal is an energised system with fundamental,
interlinked roles in cell division – coordinating the re-structuring of peptidoglycan at
division sites and stabilising the connection between the outer membrane and underlying
cell wall. This latter role is achieved by Tol-Pal exploiting the proton motive force to
catalyse the accumulation of the outer membrane peptidoglycan associated lipoprotein Pal
at division sites while simultaneously mobilising Pal molecules from around the cell.
These studies begin to explain the diverse phenotypic outcomes of tol-pal
mutations, point to other cell envelope roles Tol-Pal may have and raise many new
questions.
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Affiliation(s)
- Joanna Szczepaniak
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
| | - Cara Press
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
| | - Colin Kleanthous
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
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13
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Lunar Silva I, Cascales E. Molecular Strategies Underlying Porphyromonas gingivalis Virulence. J Mol Biol 2021; 433:166836. [PMID: 33539891 DOI: 10.1016/j.jmb.2021.166836] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/15/2021] [Accepted: 01/15/2021] [Indexed: 02/07/2023]
Abstract
The anaerobic Gram-negative bacterium Porphyromonas gingivalis is considered the keystone of periodontitis diseases, a set of inflammatory conditions that affects the tissues surrounding the teeth. In the recent years, the major virulence factors exploited by P. gingivalis have been identified and characterized, including a cocktail of toxins, mainly proteases called gingipains, which promote gingival tissue invasion. These effectors use the Sec pathway to cross the inner membrane and are then recruited and transported across the outer membrane by the type IX secretion system (T9SS). In P. gingivalis, most secreted effectors are attached to anionic lipopolysaccharides (A-LPS), and hence form a virulence coat at the cell surface. P. gingivalis produces additional virulence factors to evade host immune responses, such as capsular polysaccharide, fimbriae and outer membrane vesicles. In addition to periodontitis, it is proposed that this broad repertoire of virulence factors enable P. gingivalis to be involved in diverse human diseases such as rheumatoid arthritis, and neurodegenerative, Alzheimer, and cardiovascular disorders. Here, we review the major virulence determinants of P. gingivalis and discuss future directions to better understand their mechanisms of action.
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Affiliation(s)
- Ignacio Lunar Silva
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, 31 Chemin Joseph Aiguier CS7071, 13009 Marseille Cedex 20, France.
| | - Eric Cascales
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, 31 Chemin Joseph Aiguier CS7071, 13009 Marseille Cedex 20, France.
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14
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Deme JC, Johnson S, Vickery O, Aron A, Monkhouse H, Griffiths T, James RH, Berks BC, Coulton JW, Stansfeld PJ, Lea SM. Structures of the stator complex that drives rotation of the bacterial flagellum. Nat Microbiol 2020; 5:1553-1564. [PMID: 32929189 PMCID: PMC7610383 DOI: 10.1038/s41564-020-0788-8] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/11/2020] [Indexed: 01/17/2023]
Abstract
The bacterial flagellum is the prototypical protein nanomachine and comprises a rotating helical propeller attached to a membrane-embedded motor complex. The motor consists of a central rotor surrounded by stator units that couple ion flow across the cytoplasmic membrane to generate torque. Here, we present the structures of the stator complexes from Clostridium sporogenes, Bacillus subtilis and Vibrio mimicus, allowing interpretation of the extensive body of data on stator mechanism. The structures reveal an unexpected asymmetric A5B2 subunit assembly where the five A subunits enclose the two B subunits. Comparison to structures of other ion-driven motors indicates that this A5B2 architecture is fundamental to bacterial systems that couple energy from ion flow to generate mechanical work at a distance and suggests that such events involve rotation in the motor structures.
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Affiliation(s)
- Justin C Deme
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Owen Vickery
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences & Department of Chemistry, University of Warwick, Coventry, UK
| | - Amy Aron
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Holly Monkhouse
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Thomas Griffiths
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Ben C Berks
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - James W Coulton
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Département de Biochemie et Médecine Moleculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences & Department of Chemistry, University of Warwick, Coventry, UK
| | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK.
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15
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Ratliff AC, Buchanan SK, Celia H. Ton motor complexes. Curr Opin Struct Biol 2020; 67:95-100. [PMID: 33157479 DOI: 10.1016/j.sbi.2020.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022]
Abstract
The Ton complex is a molecular motor that uses the proton gradient at the inner membrane of Gram-negative bacteria to apply forces on outer membrane proteins, allowing active transport of nutrients into the periplasmic space. For decades, contradictory data has been reported on the structure and stoichiometry of the Ton complex. However, recent reports strongly support a subunit stoichiometry of 5:2 for the ExbB-ExbD subcomplex. In this review, we summarize the recent discoveries of the structures and proposed mechanisms of the Ton system, as well as similar protein motor complexes in Gram-negative bacteria.
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Affiliation(s)
- Anna C Ratliff
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Susan K Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Herve Celia
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
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16
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Santiveri M, Roa-Eguiara A, Kühne C, Wadhwa N, Hu H, Berg HC, Erhardt M, Taylor NM. Structure and Function of Stator Units of the Bacterial Flagellar Motor. Cell 2020; 183:244-257.e16. [DOI: 10.1016/j.cell.2020.08.016] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/09/2020] [Accepted: 08/11/2020] [Indexed: 12/17/2022]
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17
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Ruhe ZC, Low DA, Hayes CS. Polymorphic Toxins and Their Immunity Proteins: Diversity, Evolution, and Mechanisms of Delivery. Annu Rev Microbiol 2020; 74:497-520. [PMID: 32680451 DOI: 10.1146/annurev-micro-020518-115638] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
All bacteria must compete for growth niches and other limited environmental resources. These existential battles are waged at several levels, but one common strategy entails the transfer of growth-inhibitory protein toxins between competing cells. These antibacterial effectors are invariably encoded with immunity proteins that protect cells from intoxication by neighboring siblings. Several effector classes have been described, each designed to breach the cell envelope of target bacteria. Although effector architectures and export pathways tend to be clade specific, phylogenetically distant species often deploy closely related toxin domains. Thus, diverse competition systems are linked through a common reservoir of toxin-immunity pairs that is shared via horizontal gene transfer. These toxin-immunity protein pairs are extraordinarily diverse in sequence, and this polymorphism underpins an important mechanism of self/nonself discrimination in bacteria. This review focuses on the structures, functions, and delivery mechanisms of polymorphic toxin effectors that mediate bacterial competition.
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Affiliation(s)
- Zachary C Ruhe
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, USA;
| | - David A Low
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, USA; .,Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
| | - Christopher S Hayes
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California 93106, USA; .,Biomolecular Science and Engineering Program, University of California, Santa Barbara, California 93106, USA
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18
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Bacterial flagellar motor PL-ring disassembly subcomplexes are widespread and ancient. Proc Natl Acad Sci U S A 2020; 117:8941-8947. [PMID: 32241888 PMCID: PMC7183148 DOI: 10.1073/pnas.1916935117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In order to understand the evolution of complex biological machines like the bacterial flagellar motor, it is crucial to know what each component does and when it arose. Here, we show that a subcomplex of the motor thought to act as a bushing for the spinning motor likely also serves another function—it plugs the hole in the outer membrane left when the flagellum disassembles. Moreover, this component and function is ancient, since it appears in diverse phyla without evidence of recent gene transfer. The bacterial flagellum is an amazing nanomachine. Understanding how such complex structures arose is crucial to our understanding of cellular evolution. We and others recently reported that in several Gammaproteobacterial species, a relic subcomplex comprising the decorated P and L rings persists in the outer membrane after flagellum disassembly. Imaging nine additional species with cryo-electron tomography, here, we show that this subcomplex persists after flagellum disassembly in other phyla as well. Bioinformatic analyses fail to show evidence of any recent horizontal transfers of the P- and L-ring genes, suggesting that this subcomplex and its persistence is an ancient and conserved feature of the flagellar motor. We hypothesize that one function of the P and L rings is to seal the outer membrane after motor disassembly.
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19
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The Intrinsically Disordered Region of ExbD Is Required for Signal Transduction. J Bacteriol 2020; 202:JB.00687-19. [PMID: 31932309 DOI: 10.1128/jb.00687-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 01/03/2020] [Indexed: 12/26/2022] Open
Abstract
The TonB system actively transports vital nutrients across the unenergized outer membranes of the majority of Gram-negative bacteria. In this system, integral membrane proteins ExbB, ExbD, and TonB work together to transduce the proton motive force (PMF) of the inner membrane to customized active transporters in the outer membrane by direct and cyclic binding of TonB to the transporters. A PMF-dependent TonB-ExbD interaction is prevented by 10-residue deletions within a periplasmic disordered domain of ExbD adjacent to the cytoplasmic membrane. Here, we explored the function of the ExbD disordered domain in more detail. In vivo photo-cross-linking through sequential pBpa substitutions in the ExbD disordered domain captured five different ExbD complexes, some of which had been previously detected using in vivo formaldehyde cross-linking, a technique that lacks the residue-specific information that can be achieved through photo-cross-linking: two ExbB-ExbD heterodimers (one of which had not been detected previously), previously detected ExbD homodimers, previously detected PMF-dependent ExbD-TonB heterodimers, and for the first time, a predicted, ExbD-TonB PMF-independent interaction. The fact that multiple complexes were captured by the same pBpa substitution indicated the dynamic nature of ExbD interactions as the energy transduction cycle proceeded in vivo In this study, we also discovered that a conserved motif-V45, V47, L49, and P50-within the disordered domain was required for signal transduction to TonB and to the C-terminal domain of ExbD and was the source of motif essentiality.IMPORTANCE The TonB system is a virulence factor for Gram-negative pathogens. The mechanism by which cytoplasmic membrane proteins of the TonB system transduce an electrochemical gradient into mechanical energy is a long-standing mystery. TonB, ExbB, and ExbD primary amino acid sequences are characterized by regions of predicted intrinsic disorder, consistent with a proposed multiplicity of protein-protein contacts as TonB proceeds through an energy transduction cycle, a complex process that has yet to be recapitulated in vitro This study validates a region of intrinsic disorder near the ExbD transmembrane domain and identifies an essential conserved motif embedded within it that transduces signals to distal regions of ExbD suggested to configure TonB for productive interaction with outer membrane transporters.
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20
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Szczepaniak J, Holmes P, Rajasekar K, Kaminska R, Samsudin F, Inns PG, Rassam P, Khalid S, Murray SM, Redfield C, Kleanthous C. The lipoprotein Pal stabilises the bacterial outer membrane during constriction by a mobilisation-and-capture mechanism. Nat Commun 2020; 11:1305. [PMID: 32161270 PMCID: PMC7066135 DOI: 10.1038/s41467-020-15083-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/13/2020] [Indexed: 11/24/2022] Open
Abstract
Coordination of outer membrane constriction with septation is critical to faithful division in Gram-negative bacteria and vital to the barrier function of the membrane. This coordination requires the recruitment of the peptidoglycan-binding outer-membrane lipoprotein Pal at division sites by the Tol system. Here, we show that Pal accumulation at Escherichia coli division sites is a consequence of three key functions of the Tol system. First, Tol mobilises Pal molecules in dividing cells, which otherwise diffuse very slowly due to their binding of the cell wall. Second, Tol actively captures mobilised Pal molecules and deposits them at the division septum. Third, the active capture mechanism is analogous to that used by the inner membrane protein TonB to dislodge the plug domains of outer membrane TonB-dependent nutrient transporters. We conclude that outer membrane constriction is coordinated with cell division by active mobilisation-and-capture of Pal at division septa by the Tol system.
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Affiliation(s)
| | - Peter Holmes
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Department of Biochemistry, University of Alberta, Edmonton, AB, T6G 2H7, Canada
| | - Karthik Rajasekar
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Evotec SE, 112-114 Innovation Drive, Milton Park, Abingdon, OX14 4RZ, UK
| | - Renata Kaminska
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Firdaus Samsudin
- Department of Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | | | - Patrice Rassam
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
- Laboratoire de Bioimagerie et Pathologie, UMR 7021, CNRS, Université de Strasbourg, Faculté de pharmacie, 74 Route du Rhin, 67401, Illkirch, France
| | - Syma Khalid
- Department of Chemistry, University of Southampton, University Road, Southampton, SO17 1BJ, UK
| | - Seán M Murray
- Max Planck Institute for Terrestrial Microbiology and LOEWE Centre for Synthetic Microbiology (SYNMIKRO), Karl-von-Frisch Strasse 16, 35043, Marburg, Germany
| | | | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK.
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21
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Beeby M, Ferreira JL, Tripp P, Albers SV, Mitchell DR. Propulsive nanomachines: the convergent evolution of archaella, flagella and cilia. FEMS Microbiol Rev 2020; 44:253-304. [DOI: 10.1093/femsre/fuaa006] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 03/06/2020] [Indexed: 02/06/2023] Open
Abstract
ABSTRACT
Echoing the repeated convergent evolution of flight and vision in large eukaryotes, propulsive swimming motility has evolved independently in microbes in each of the three domains of life. Filamentous appendages – archaella in Archaea, flagella in Bacteria and cilia in Eukaryotes – wave, whip or rotate to propel microbes, overcoming diffusion and enabling colonization of new environments. The implementations of the three propulsive nanomachines are distinct, however: archaella and flagella rotate, while cilia beat or wave; flagella and cilia assemble at their tips, while archaella assemble at their base; archaella and cilia use ATP for motility, while flagella use ion-motive force. These underlying differences reflect the tinkering required to evolve a molecular machine, in which pre-existing machines in the appropriate contexts were iteratively co-opted for new functions and whose origins are reflected in their resultant mechanisms. Contemporary homologies suggest that archaella evolved from a non-rotary pilus, flagella from a non-rotary appendage or secretion system, and cilia from a passive sensory structure. Here, we review the structure, assembly, mechanism and homologies of the three distinct solutions as a foundation to better understand how propulsive nanomachines evolved three times independently and to highlight principles of molecular evolution.
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Affiliation(s)
- Morgan Beeby
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Josie L Ferreira
- Department of Life Sciences, Frankland Road, Imperial College of London, London, SW7 2AZ, UK
| | - Patrick Tripp
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - Sonja-Verena Albers
- Molecular Biology of Archaea, Institute of Biology, University of Freiburg, Schaenzlestrasse 1, 79211 Freiburg, Germany
| | - David R Mitchell
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, 750 E. Adams St., Syracuse, NY 13210, USA
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22
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Abstract
The bacterial flagellar motor is driven by an ion flux that is converted to torque by motor-attendant complexes known as stators. The dynamics of stator assembly around the motor in response to external stimuli have been the subject of much recent research, but less is known about the evolutionary origins of stator complexes and how they select for specific ions. Here, we review the latest structural and biochemical data for the stator complexes and compare these with other ion transporters and microbial motors to examine possible evolutionary origins of the stator complex.
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23
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Decoupling Filamentous Phage Uptake and Energy of the TolQRA Motor in Escherichia coli. J Bacteriol 2020; 202:JB.00428-19. [PMID: 31636109 DOI: 10.1128/jb.00428-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/18/2019] [Indexed: 12/15/2022] Open
Abstract
Filamentous phages are nonlytic viruses that specifically infect bacteria, establishing a persistent association with their host. The phage particle has no machinery for generating energy and parasitizes its host's existing structures in order to cross the bacterial envelope and deliver its genetic material. The import of filamentous phages across the bacterial periplasmic space requires some of the components of a macrocomplex of the envelope known as the Tol system. This complex uses the energy provided by the proton motive force (pmf) of the inner membrane to perform essential and highly energy-consuming functions of the cell, such as envelope integrity maintenance and cell division. It has been suggested that phages take advantage of pmf-driven conformational changes in the Tol system to transit across the periplasm. However, this hypothesis has not been formally tested. In order to decouple the role of the Tol system in cell physiology and during phage parasitism, we used mutations on conserved essential residues known for inactivating pmf-dependent functions of the Tol system. We identified impaired Tol complexes that remain fully efficient for filamentous phage uptake. We further demonstrate that the TolQ-TolR homologous motor ExbB-ExbD, normally operating with the TonB protein, is able to promote phage infection along with full-length TolA.IMPORTANCE Filamentous phages are widely distributed symbionts of Gram-negative bacteria, with some of them being linked to genome evolution and virulence of their host. However, the precise mechanism that permits their uptake across the cell envelope is poorly understood. The canonical phage model Fd requires the TolQRA protein complex in the host envelope, which is suspected to translocate protons across the inner membrane. In this study, we show that phage uptake proceeds in the presence of the assembled but nonfunctional TolQRA complex. Moreover, our results unravel an alternative route for phage import that relies on the ExbB-ExbD proteins. This work provides new insights into the fundamental mechanisms of phage infection and might be generalized to other filamentous phages responsible for pathogen emergence.
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24
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Romero-Romero S, Martínez-Delgado G, Balleza D. Voltage vs. Ligand II: Structural insights of the intrinsic flexibility in cyclic nucleotide-gated channels. Channels (Austin) 2019; 13:382-399. [PMID: 31552786 PMCID: PMC6768053 DOI: 10.1080/19336950.2019.1666456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 08/30/2019] [Accepted: 09/03/2019] [Indexed: 12/23/2022] Open
Abstract
In the preceding article, we present a flexibility analysis of the voltage-gated ion channel (VGIC) superfamily. In this study, we describe in detail the flexibility profile of the voltage-sensor domain (VSD) and the pore domain (PD) concerning the evolution of 6TM ion channels. In particular, we highlight the role of flexibility in the emergence of CNG channels and describe a significant level of sequence similarity between the archetypical VSD and the TolQ proteins. A highly flexible S4-like segment exhibiting Lys instead Arg for these membrane proteins is reported. Sequence analysis indicates that, in addition to this S4-like segment, TolQ proteins also show similarity with specific motifs in S2 and S3 from typical V-sensors. Notably, S3 flexibility profiles from typical VSDs and S3-like in TolQ proteins are also similar. Interestingly, TolQ from early divergent prokaryotes are comparatively more flexible than those in modern counterparts or true V-sensors. Regarding the PD, we also found that 2TM K+-channels in early prokaryotes are considerably more flexible than the ones in modern microbes, and such flexibility is comparable to the one present in CNG channels. Voltage dependence is mainly exhibited in prokaryotic CNG channels whose VSD is rigid whereas the eukaryotic CNG channels are considerably more flexible and poorly V-dependent. The implication of the flexibility present in CNG channels, their sensitivity to cyclic nucleotides and the cation selectivity are discussed. Finally, we generated a structural model of the putative cyclic nucleotide-modulated ion channel, which we coined here as AqK, from the thermophilic bacteria Aquifex aeolicus, one of the earliest diverging prokaryotes known. Overall, our analysis suggests that V-sensors in CNG-like channels were essentially rigid in early prokaryotes but raises the possibility that this module was probably part of a very flexible stator protein of the bacterial flagellum motor complex.
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Affiliation(s)
- Sergio Romero-Romero
- Facultad de Medicina, Departamento de Bioquímica, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico. Current address: Department of Biochemistry, University of Bayreuth, Bayreuth, Germany
| | - Gustavo Martínez-Delgado
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Daniel Balleza
- Departamento de Química ICET, Universidad Autónoma de Guadalajara, Zapopan, Jalisco, Mexico
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25
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Sharma D, Sharma A, Singh B, Verma SK. Bioinformatic Exploration of Metal-Binding Proteome of Zoonotic Pathogen Orientia tsutsugamushi. Front Genet 2019; 10:797. [PMID: 31608099 PMCID: PMC6769048 DOI: 10.3389/fgene.2019.00797] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/30/2019] [Indexed: 12/21/2022] Open
Abstract
Metal ions are involved in many essential biological processes and are crucial for the survival of all organisms. Identification of metal-binding proteins (MBPs) of human affecting pathogens may provide the blueprint for understanding biological metal usage and their putative roles in pathogenesis. This study is focused on the analysis of MBPs from Orientia tsutsugamushi (Ott), a causal agent of scrub typhus in humans. A total of 321 proteins were predicted as putative MBPs, based on sequence search and three-dimensional structure analysis. Majority of proteins could bind with magnesium, and the order of metal binding was Mg > Ca > Zn > Mn > Fe > Cd > Ni > Co > Cu, respectively. The predicted MBPs were functionally classified into nine broad classes. Among them, gene expression and regulation, metabolism, cell signaling, and transport classes were dominant. It was noted that the putative MBPs were localized in all subcellular compartments of Ott, but majorly found in the cytoplasm. Additionally, it was revealed that out of 321 predicted MBPs 245 proteins were putative bacterial toxins and among them, 98 proteins were nonhomologous to human proteome. Sixty putative MBPs showed the ability to interact with drug or drug-like molecules, which indicate that they may be used as broad-spectrum drug targets. These predicted MBPs from Ott could play vital role(s) in various cellular activities and virulence, hence may serve as plausible therapeutic targets to design metal-based drugs to curtail its infection.
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Affiliation(s)
- Dixit Sharma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, India
| | - Ankita Sharma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, India
| | - Birbal Singh
- ICAR-Indian Veterinary Research Institute, Regional Station, Palampur, India
| | - Shailender Kumar Verma
- Centre for Computational Biology and Bioinformatics, School of Life Sciences, Central University of Himachal Pradesh, Kangra, India
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Kirchweger P, Weiler S, Egerer‐Sieber C, Blasl A, Hoffmann S, Schmidt C, Sander N, Merker D, Gerlach RG, Hensel M, Muller YA. Structural and functional characterization of SiiA, an auxiliary protein from the SPI4‐encoded type 1 secretion system from
Salmonella enterica. Mol Microbiol 2019; 112:1403-1422. [DOI: 10.1111/mmi.14368] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Peter Kirchweger
- Division of Biotechnology, Department of Biology Friedrich‐Alexander‐University Erlangen‐Nürnberg Henkestr. 91D‐91052Erlangen Germany
| | - Sigrid Weiler
- Division of Biotechnology, Department of Biology Friedrich‐Alexander‐University Erlangen‐Nürnberg Henkestr. 91D‐91052Erlangen Germany
| | - Claudia Egerer‐Sieber
- Division of Biotechnology, Department of Biology Friedrich‐Alexander‐University Erlangen‐Nürnberg Henkestr. 91D‐91052Erlangen Germany
| | - Anna‐Theresa Blasl
- Division of Biotechnology, Department of Biology Friedrich‐Alexander‐University Erlangen‐Nürnberg Henkestr. 91D‐91052Erlangen Germany
| | | | | | - Nathalie Sander
- Abt. Mikrobiologie and CellNanOs Universität Osnabrück Osnabrück Germany
| | - Dorothee Merker
- Abt. Mikrobiologie and CellNanOs Universität Osnabrück Osnabrück Germany
| | | | - Michael Hensel
- Abt. Mikrobiologie and CellNanOs Universität Osnabrück Osnabrück Germany
| | - Yves A. Muller
- Division of Biotechnology, Department of Biology Friedrich‐Alexander‐University Erlangen‐Nürnberg Henkestr. 91D‐91052Erlangen Germany
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27
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Brangulis K, Akopjana I, Kazaks A, Tars K. Crystal structure of the N-terminal domain of the major virulence factor BB0323 from the Lyme disease agent Borrelia burgdorferi. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:825-830. [PMID: 31478905 DOI: 10.1107/s2059798319010751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/01/2019] [Indexed: 01/30/2023]
Abstract
Lyme disease is an infection caused by the spirochete Borrelia burgdorferi after it is transmitted to a mammalian organism during a tick blood meal. B. burgdorferi encodes at least 140 lipoproteins located on the outer or inner membrane, thus facing the surroundings or the periplasmic space, respectively. However, most of the predicted lipoproteins are of unknown function, and only a few proteins are known to be essential for the persistence and virulence of the pathogen. One such protein is the periplasmic BB0323, which is indispensable for B. burgdorferi to cause Lyme disease and the function of which is associated with cell fission and outer membrane integrity. After expression and transport to the periplasm, BB0323 is cleaved into C-terminal and N-terminal domains by the periplasmic serine protease BB0104. The resulting N-terminal domain is sufficient to ensure the survival of B. burgdorferi throughout the mouse-tick infection cycle. The crystal structure of the N-terminal domain of BB0323 was determined at 2.35 Å resolution. The overall fold of the protein belongs to the spectrin superfamily, with the characteristic interconnected triple-helical bundles known as spectrin repeats that function as linkers between different cell components in other organisms. Overall, the reported three-dimensional structure of the N-terminal domain of BB0323 not only reveals the molecular details of a protein that is essential for B. burgdorferi membrane integrity, cell fission and infectivity, but also suggests that spectrin repeats in bacteria are not limited to the EzrA proteins.
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Affiliation(s)
- Kalvis Brangulis
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, Riga, LV-1067, Latvia
| | - Inara Akopjana
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, Riga, LV-1067, Latvia
| | - Andris Kazaks
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, Riga, LV-1067, Latvia
| | - Kaspars Tars
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k-1, Riga, LV-1067, Latvia
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Abstract
The outer membrane (OM) of Gram-negative bacteria exhibits unique lipid asymmetry, with lipopolysaccharides (LPS) residing in the outer leaflet and phospholipids (PLs) in the inner leaflet. This asymmetric bilayer protects the bacterium against intrusion of many toxic substances, including antibiotics and detergents, yet allows acquisition of nutrients necessary for growth. To build the OM and ensure its proper function, the cell produces OM constituents in the cytoplasm or inner membrane and transports these components across the aqueous periplasmic space separating the two membranes. Of note, the processes by which the most basic membrane building blocks, i.e. PLs, are shuttled across the cell envelope remain elusive. This review highlights our current understanding (or lack thereof) of bacterial PL trafficking, with a focus on recent developments in the field. We adopt a mechanistic approach and draw parallels and comparisons with well-characterized systems, particularly OM lipoprotein and LPS transport, to illustrate key challenges in intermembrane lipid trafficking. Pathways that transport PLs across the bacterial cell envelope are fundamental to OM biogenesis and homeostasis and are potential molecular targets that could be exploited for antibiotic development.
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Affiliation(s)
- Rahul Shrivastava
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore 117543, Singapore
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29
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Tol Energy-Driven Localization of Pal and Anchoring to the Peptidoglycan Promote Outer-Membrane Constriction. J Mol Biol 2019; 431:3275-3288. [DOI: 10.1016/j.jmb.2019.05.039] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/21/2019] [Accepted: 05/24/2019] [Indexed: 02/06/2023]
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30
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Jacek P, Ryngajłło M, Bielecki S. Structural changes of bacterial nanocellulose pellicles induced by genetic modification of Komagataeibacter hansenii ATCC 23769. Appl Microbiol Biotechnol 2019; 103:5339-5353. [PMID: 31037382 PMCID: PMC6570709 DOI: 10.1007/s00253-019-09846-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 01/08/2023]
Abstract
Bacterial nanocellulose (BNC) synthesized by Komagataeibacter hansenii is a polymer that recently gained an attention of tissue engineers, since its features make it a suitable material for scaffolds production. Nevertheless, it is still necessary to modify BNC to improve its properties in order to make it more suitable for biomedical use. One approach to address this issue is to genetically engineer K. hansenii cells towards synthesis of BNC with modified features. One of possible ways to achieve that is to influence the bacterial movement or cell morphology. In this paper, we described for the first time, K. hansenii ATCC 23769 motA+ and motB+ overexpression mutants, which displayed elongated cell phenotype, increased motility, and productivity. Moreover, the mutant cells produced thicker ribbons of cellulose arranged in looser network when compared to the wild-type strain. In this paper, we present a novel development in obtaining BNC membranes with improved properties using genetic engineering tools.
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Affiliation(s)
- Paulina Jacek
- Institute of Technical Biochemistry, Lodz University of Technology, B. Stefanowskiego 4/10, 90-924 Lodz, Poland
| | - Małgorzata Ryngajłło
- Institute of Technical Biochemistry, Lodz University of Technology, B. Stefanowskiego 4/10, 90-924 Lodz, Poland
| | - Stanisław Bielecki
- Institute of Technical Biochemistry, Lodz University of Technology, B. Stefanowskiego 4/10, 90-924 Lodz, Poland
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Abstract
Bacteria move by a variety of mechanisms, but the best understood types of motility are powered by flagella (72). Flagella are complex machines embedded in the cell envelope that rotate a long extracellular helical filament like a propeller to push cells through the environment. The flagellum is one of relatively few biological machines that experience continuous 360° rotation, and it is driven by one of the most powerful motors, relative to its size, on earth. The rotational force (torque) generated at the base of the flagellum is essential for motility, niche colonization, and pathogenesis. This review describes regulatory proteins that control motility at the level of torque generation.
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Affiliation(s)
- Sundharraman Subramanian
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.,Biochemistry Graduate Program, Indiana University, Bloomington, Indiana 47405, USA
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA;
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32
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Duché D, Houot L. Similarities and Differences between Colicin and Filamentous Phage Uptake by Bacterial Cells. EcoSal Plus 2019; 8. [PMID: 30681066 DOI: 10.1128/ecosalplus.esp-0030-2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Indexed: 06/09/2023]
Abstract
Gram-negative bacteria have evolved a complex envelope to adapt and survive in a broad range of ecological niches. This physical barrier is the first line of defense against noxious compounds and viral particles called bacteriophages. Colicins are a family of bactericidal proteins produced by and toxic to Escherichia coli and closely related bacteria. Filamentous phages have a complex structure, composed of at least five capsid proteins assembled in a long thread-shaped particle, that protects the viral DNA. Despite their difference in size and complexity, group A colicins and filamentous phages both parasitize multiprotein complexes of their sensitive host for entry. They first bind to a receptor located at the surface of the target bacteria before specifically recruiting components of the Tol system to cross the outer membrane and find their way through the periplasm. The Tol system is thought to use the proton motive force of the inner membrane to maintain outer membrane integrity during the life cycle of the cell. This review describes the sequential docking mechanisms of group A colicins and filamentous phages during their uptake by their bacterial host, with a specific focus on the translocation step, promoted by interactions with the Tol system.
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Affiliation(s)
- Denis Duché
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 13402 Marseille, France
| | - Laetitia Houot
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université- CNRS, 13402 Marseille, France
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Abstract
The peptidoglycan sacculus is a net-like polymer that surrounds the cytoplasmic membrane in most bacteria. It is essential to maintain the bacterial cell shape and protect from turgor. The peptidoglycan has a basic composition, common to all bacteria, with species-specific variations that can modify its biophysical properties or the pathogenicity of the bacteria. The synthesis of peptidoglycan starts in the cytoplasm and the precursor lipid II is flipped across the cytoplasmic membrane. The new peptidoglycan strands are synthesised and incorporated into the pre-existing sacculus by the coordinated activities of peptidoglycan synthases and hydrolases. In the model organism Escherichia coli there are two complexes required for the elongation and division. Each of them is regulated by different proteins from both the cytoplasmic and periplasmic sides that ensure the well-coordinated synthesis of new peptidoglycan.
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Jacek P, Szustak M, Kubiak K, Gendaszewska-Darmach E, Ludwicka K, Bielecki S. Scaffolds for Chondrogenic Cells Cultivation Prepared from Bacterial Cellulose with Relaxed Fibers Structure Induced Genetically. NANOMATERIALS (BASEL, SWITZERLAND) 2018; 8:E1066. [PMID: 30563030 PMCID: PMC6315621 DOI: 10.3390/nano8121066] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/06/2018] [Accepted: 12/14/2018] [Indexed: 11/16/2022]
Abstract
Development of three-dimensional scaffolds mimicking in vivo cells' environment is an ongoing challenge for tissue engineering. Bacterial nano-cellulose (BNC) is a well-known biocompatible material with enormous water-holding capacity. However, a tight spatial organization of cellulose fibers limits cell ingrowth and restricts practical use of BNC-based scaffolds. The aim of this study was to address this issue avoiding any chemical treatment of natural nanomaterial. Genetic modifications of Komagataeibacter hansenii ATCC 23769 strain along with structural and mechanical properties characterization of obtained BNC membranes were conducted. Furthermore, the membranes were evaluated as scaffolds in in vitro assays to verify cells viability and glycosaminoglycan synthesis by chondrogenic ATDC5 cells line as well as RBL-2H3 mast cells degranulation. K. hansenii mutants with increased cell lengths and motility were shown to produce BNC membranes with increased pore sizes. Novel, BNC membranes with relaxed fiber structure revealed superior properties as scaffolds when compared to membranes produced by a wild-type strain. Obtained results confirm that a genetic modification of productive bacterial strain is a plausible way of adjustment of bacterial cellulose properties for tissue engineering applications without the employment of any chemical modifications.
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Affiliation(s)
- Paulina Jacek
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Marcin Szustak
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Katarzyna Kubiak
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Edyta Gendaszewska-Darmach
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Karolina Ludwicka
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
| | - Stanisław Bielecki
- Institute of Technical Biochemistry, Lodz University of Technology, 4/10 Stefanowskiego Str., 90-924 Łódź, Poland.
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35
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On mechanisms of colicin import: the outer membrane quandary. Biochem J 2018; 475:3903-3915. [PMID: 30541793 DOI: 10.1042/bcj20180477] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/02/2018] [Accepted: 11/12/2018] [Indexed: 01/09/2023]
Abstract
Current problems in the understanding of colicin import across the Escherichia coli outer membrane (OM), involving a range of cytotoxic mechanisms, are discussed: (I) Crystal structure analysis of colicin E3 (RNAase) with bound OM vitamin B12 receptor, BtuB, and of the N-terminal translocation (T) domain of E3 and E9 (DNAase) inserted into the OM OmpF porin, provide details of the initial interaction of the colicin central receptor (R)- and N-terminal T-domain with OM receptors/translocators. (II) Features of the translocon include: (a) high-affinity (K d ≈ 10-9 M) binding of the E3 receptor-binding R-domain E3 to BtuB; (b) insertion of disordered colicin N-terminal domain into the OmpF trimer; (c) binding of the N-terminus, documented for colicin E9, to the TolB protein on the periplasmic side of OmpF. Reinsertion of the colicin N-terminus into the second of the three pores in OmpF implies a colicin anchor site on the periplasmic side of OmpF. (III) Studies on the insertion of nuclease colicins into the cytoplasmic compartment imply that translocation proceeds via the C-terminal catalytic domain, proposed here to insert through the unoccupied third pore of the OmpF trimer, consistent with in vitro occlusion of OmpF channels by the isolated E3 C-terminal domain. (IV) Discussion of channel-forming colicins focuses mainly on colicin E1 for which BtuB is receptor and the OM TolC protein the proposed translocator. The ability of TolC, part of a multidrug efflux pump, for which there is no precedent for an import function, to provide a trans-periplasmic import pathway for colicin E1, is questioned on the basis of an unfavorable hairpin conformation of colicin N-terminal peptides inserted into TolC.
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36
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Salmonella Tol-Pal Reduces Outer Membrane Glycerophospholipid Levels for Envelope Homeostasis and Survival during Bacteremia. Infect Immun 2018; 86:IAI.00173-18. [PMID: 29735519 PMCID: PMC6013679 DOI: 10.1128/iai.00173-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 04/27/2018] [Indexed: 12/22/2022] Open
Abstract
Salmonellae regulate membrane lipids during infection, but the exact proteins and mechanisms that promote their survival during bacteremia remain largely unknown. Mutations in genes encoding the conserved Salmonella enterica serovar Typhimurium (S. Typhimurium) Tol-Pal apparatus caused the outer membrane (OM) sensor lipoprotein, RcsF, to become activated. The capsule activation phenotype for the mutants suggested that Tol-Pal might influence envelope lipid homeostasis. The mechanism involves reducing OM glycerophospholipid (GPL) levels, since the mutant salmonellae similarly accumulated phosphatidylglycerols (PGl) and phosphatidylethanolamines (PE) within the OM in comparison to the wild type. The data support the Escherichia coli model, whereby Tol-Pal directs retrograde GPL translocation across the periplasm. The S. Typhimurium mechanism involves contributions from YbgC, a cytoplasmic acyl coenzyme A (acyl-CoA) thioesterase, and CpoB, a periplasmic TolA-binding protein. The functional relationship between Tol-Pal and YbgC and CpoB was previously unresolved. The S. Typhimurium Tol-Pal proteins contribute similarly toward promoting OM-GPL homeostasis and Rcs signaling inactivity but differently toward promoting bacterial morphology, rifampin resistance, survival in macrophages, and survival in mice. For example, tolQ, tolR, tolA, and cpoB mutants were significantly more attenuated than ybgC, tolB, and pal mutants in a systemic mouse model of disease. Therefore, key roles exist for TolQ, TolR, TolA, and CpoB during murine bacteremia, which are independent of maintaining GPL homeostasis. The ability of TolQR to channel protons across the inner membrane (IM) is necessary for S. Typhimurium TolQRA function, since mutating conserved channel-facing residues rendered TolQ ineffective at rescuing deletion mutant phenotypes. Therefore, Tol-Pal promotes S. Typhimurium survival during bacteremia, in part, by reducing OM GPL concentrations, while TolQRA and CpoB enhance systemic virulence by additional mechanisms.
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37
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Abstract
Piscirickettsia salmonis, a fastidious Gram-negative intracellular facultative bacterium, is the causative agent o Piscirickettsiosis. P. salmonis has broad host range with a nearly worldwide distribution, causing significant mortality. The molecular regulatory mechanisms of P. salmonis pathogenesis are relatively unknown, mainly due to its difficult in vitro culture and genomic differences between genogroups. Bacterial non-coding RNAs (ncRNAs) are important post-transcriptional regulators of bacterial physiology and virulence that are predominantly transcribed from intergenic regions (trans-acting) or antisense strand of open reading frames (cis-acting). The repertoire of ncRNAs present in the genome of P. salmonis and its possible role in bacterial physiology and pathogenesis are unknown. Here, we predicted and analyzed the core ncRNAs of P. salmonis base on structure and correlate this prediction to RNA sequencing data. We identified a total of 69 ncRNA classes related to tRNAs, rRNA, thermoregulators, antitoxins, ribozymes, riboswitches, miRNAs and antisense-RNAs. Among these ncRNAs, 29 classes of ncRNAs are shared between all P. salmonis genomes, constituting the core ncRNAs of P. salmonis. The ncRNA core of P. salmonis could serve to develop diagnostic tools and explore the role of ncRNA in fish pathogenesis.
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38
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Tryptophan-mediated Dimerization of the TssL Transmembrane Anchor Is Required for Type VI Secretion System Activity. J Mol Biol 2018; 430:987-1003. [DOI: 10.1016/j.jmb.2018.02.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 01/29/2018] [Accepted: 02/11/2018] [Indexed: 11/23/2022]
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39
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Egan AJF. Bacterial outer membrane constriction. Mol Microbiol 2018; 107:676-687. [DOI: 10.1111/mmi.13908] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Alexander J. F. Egan
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences; Newcastle University, Baddiley-Clarke Building; Newcastle upon Tyne UK
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40
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Shrivastava R, Jiang X, Chng SS. Outer membrane lipid homeostasis via retrograde phospholipid transport in Escherichia coli. Mol Microbiol 2017; 106:395-408. [PMID: 28815827 DOI: 10.1111/mmi.13772] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2017] [Indexed: 01/21/2023]
Abstract
Biogenesis of the outer membrane (OM) in Gram-negative bacteria, which is essential for viability, requires the coordinated transport and assembly of proteins and lipids, including lipopolysaccharides (LPS) and phospholipids (PLs), into the membrane. While pathways for LPS and OM protein assembly are well-studied, how PLs are transported to and from the OM is not clear. Mechanisms that ensure OM stability and homeostasis are also unknown. The trans-envelope Tol-Pal complex, whose physiological role has remained elusive, is important for OM stability. Here, we establish that the Tol-Pal complex is required for PL transport and OM lipid homeostasis in Escherichia coli. Cells lacking the complex exhibit defects in lipid asymmetry and accumulate excess PLs in the OM. This imbalance in OM lipids is due to defective retrograde PL transport in the absence of a functional Tol-Pal complex. Thus, cells ensure the assembly of a stable OM by maintaining an excess flux of PLs to the OM only to return the surplus to the inner membrane. Our findings also provide insights into the mechanism by which the Tol-Pal complex may promote OM invagination during cell division.
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Affiliation(s)
- Rahul Shrivastava
- Department of Chemistry, National University of Singapore, Singapore 117543
| | - Xiang'Er Jiang
- Department of Chemistry, National University of Singapore, Singapore 117543
| | - Shu-Sin Chng
- Department of Chemistry, National University of Singapore, Singapore 117543.,Singapore Center for Environmental Life Sciences Engineering, National University of Singapore (SCELSE-NUS), Singapore 117456
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41
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Dewachter L, Verstraeten N, Jennes M, Verbeelen T, Biboy J, Monteyne D, Pérez-Morga D, Verstrepen KJ, Vollmer W, Fauvart M, Michiels J. A Mutant Isoform of ObgE Causes Cell Death by Interfering with Cell Division. Front Microbiol 2017; 8:1193. [PMID: 28702018 PMCID: PMC5487468 DOI: 10.3389/fmicb.2017.01193] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 06/12/2017] [Indexed: 01/14/2023] Open
Abstract
Cell division is a vital part of the cell cycle that is fundamental to all life. Despite decades of intense investigation, this process is still incompletely understood. Previously, the essential GTPase ObgE, which plays a role in a myriad of basic cellular processes (such as initiation of DNA replication, chromosome segregation, and ribosome assembly), was proposed to act as a cell cycle checkpoint in Escherichia coli by licensing chromosome segregation. We here describe the effect of a mutant isoform of ObgE (ObgE∗) that causes cell death by irreversible arrest of the cell cycle at the stage of cell division. Notably, chromosome segregation is allowed to proceed normally in the presence of ObgE∗, after which cell division is blocked. Under conditions of rapid growth, ongoing cell cycles are completed before cell cycle arrest by ObgE∗ becomes effective. However, cell division defects caused by ObgE∗ then elicit lysis through formation of membrane blebs at aberrant division sites. Based on our results, and because ObgE was previously implicated in cell cycle regulation, we hypothesize that the mutation in ObgE∗ disrupts the normal role of ObgE in cell division. We discuss how ObgE∗ could reveal more about the intricate role of wild-type ObgE in division and cell cycle control. Moreover, since Obg is widely conserved and essential for viability, also in eukaryotes, our findings might be applicable to other organisms as well.
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Affiliation(s)
- Liselot Dewachter
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Natalie Verstraeten
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Michiel Jennes
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Tom Verbeelen
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
| | - Jacob Biboy
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Daniel Monteyne
- Laboratory of Molecular Parasitology, Institut de Biologie et de Médecine Moléculaires, Université Libre de BruxellesGosselies, Belgium
| | - David Pérez-Morga
- Laboratory of Molecular Parasitology, Institut de Biologie et de Médecine Moléculaires, Université Libre de BruxellesGosselies, Belgium.,Center for Microscopy and Molecular Imaging, Université Libre de BruxellesGosselies, Belgium
| | - Kevin J Verstrepen
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium.,Systems Biology Laboratory, VIB Center for MicrobiologyLeuven, Belgium
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle UniversityNewcastle upon Tyne, United Kingdom
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium.,Department of Life Sciences and Imaging, Smart Electronics Unit, ImecLeuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven - University of LeuvenLeuven, Belgium
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Houot L, Navarro R, Nouailler M, Duché D, Guerlesquin F, Lloubes R. Electrostatic interactions between the CTX phage minor coat protein and the bacterial host receptor TolA drive the pathogenic conversion of Vibrio cholerae. J Biol Chem 2017. [PMID: 28642371 DOI: 10.1074/jbc.m117.786061] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Vibrio cholerae is a natural inhabitant of aquatic environments and converts to a pathogen upon infection by a filamentous phage, CTXΦ, that transmits the cholera toxin-encoding genes. This toxigenic conversion of V. cholerae has evident implication in both genome plasticity and epidemic risk, but the early stages of the infection have not been thoroughly studied. CTXΦ transit across the bacterial periplasm requires binding between the minor coat protein named pIII and a bacterial inner-membrane receptor, TolA, which is part of the conserved Tol-Pal molecular motor. To gain insight into the TolA-pIII complex, we developed a bacterial two-hybrid approach, named Oxi-BTH, suited for studying the interactions between disulfide bond-folded proteins in the bacterial cytoplasm of an Escherichia coli reporter strain. We found that two of the four disulfide bonds of pIII are required for its interaction with TolA. By combining Oxi-BTH assays, NMR, and genetic studies, we also demonstrate that two intermolecular salt bridges between TolA and pIII provide the driving forces of the complex interaction. Moreover, we show that TolA residue Arg-325 involved in one of the two salt bridges is critical for proper functioning of the Tol-Pal system. Our results imply that to prevent host evasion, CTXΦ uses an infection strategy that targets a highly conserved protein of Gram-negative bacteria essential for the fitness of V. cholerae in its natural environment.
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Affiliation(s)
- Laetitia Houot
- From the Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Romain Navarro
- From the Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Matthieu Nouailler
- From the Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Denis Duché
- From the Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Françoise Guerlesquin
- From the Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Roland Lloubes
- From the Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université-CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
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Takekawa N, Kojima S, Homma M. Mutational analysis and overproduction effects of MotX, an essential component for motor function of Na+-driven polar flagella of Vibrio. J Biochem 2017; 161:159-166. [PMID: 28173168 DOI: 10.1093/jb/mvw061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 08/22/2016] [Indexed: 11/13/2022] Open
Abstract
The bacterial flagellar motor is a rotary motor complex composed of various proteins. The motor contains a central rod, multiple ring-like structures and stators. The Na+-driven polar flagellar motor of the marine bacterium Vibrio alginolyticus has a specific ring, called the ‘T-ring’, which consists of two periplasmic proteins, MotX and MotY. The T-ring is essential for assembly of the torque-generating unit, the PomA/PomB stator complex, into the motor. To investigate the role of the T-ring for motor function, we performed random mutagenesis of the motX gene on a plasmid. The isolated MotX mutants showed nonmotile, slow-motile, and up-motile phenotypes by the expression from the plasmid. Deletion analysis indicated that the C-terminal region and the signal peptide in MotX are not always essential for flagellar motor function. We also found that overproduction of MotX caused the delay of growth and aberrant cell shape. MotX might have unexpected roles not only in flagellar motor function but also in cell morphology control.
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Affiliation(s)
- Norihiro Takekawa
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan
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Vincent MS, Canestrari MJ, Leone P, Stathopulos J, Ize B, Zoued A, Cambillau C, Kellenberger C, Roussel A, Cascales E. Characterization of the Porphyromonas gingivalis Type IX Secretion Trans-envelope PorKLMNP Core Complex. J Biol Chem 2017; 292:3252-3261. [PMID: 28057754 DOI: 10.1074/jbc.m116.765081] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/21/2016] [Indexed: 02/03/2023] Open
Abstract
The transport of proteins at the cell surface of Bacteroidetes depends on a secretory apparatus known as type IX secretion system (T9SS). This machine is responsible for the cell surface exposition of various proteins, such as adhesins, required for gliding motility in Flavobacterium, S-layer components in Tannerella forsythia, and tooth tissue-degrading enzymes in the oral pathogen Porphyromonas gingivalis Although a number of subunits of the T9SS have been identified, we lack details on the architecture of this secretion apparatus. Here we provide evidence that five of the genes encoding the core complex of the T9SS are co-transcribed and that the gene products are distributed in the cell envelope. Protein-protein interaction studies then revealed that these proteins oligomerize and interact through a dense network of contacts.
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Affiliation(s)
- Maxence S Vincent
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Mickaël J Canestrari
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Philippe Leone
- Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France; Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Julien Stathopulos
- Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France; Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Bérengère Ize
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Abdelrahim Zoued
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France
| | - Christian Cambillau
- Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France; Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Christine Kellenberger
- Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France; Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Alain Roussel
- Architecture et Fonction des Macromolécules Biologiques, CNRS, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France; Architecture et Fonction des Macromolécules Biologiques, Aix-Marseille Université, UMR 7257, Campus de Luminy, Case 932, 13288 Marseille Cedex 09, France
| | - Eric Cascales
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR 7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Université - CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
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Abstract
Membrane proteins can assemble and form complexes in the cell envelope. In Gram-negative bacteria, a number of multiprotein complexes, including secretion systems, efflux pumps, molecular motors, and pilus assembly machines, comprise proteins from the inner and outer membranes. Besides the structures of isolated soluble domains, only a few atomic structures of these assembled molecular machines have been elucidated. To better understand the function and to solve the structure of protein complexes, it is thus necessary to design dedicated production and purification processes. Here we present cloning procedures to overproduce membrane proteins into Escherichia coli cells and describe the cloning and purification strategy for the Type VI secretion TssJLM membrane complex.
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Celia H, Noinaj N, Zakharov SD, Bordignon E, Botos I, Santamaria M, Barnard TJ, Cramer WA, Lloubes R, Buchanan SK. Structural insight into the role of the Ton complex in energy transduction. Nature 2016; 538:60-65. [PMID: 27654919 PMCID: PMC5161667 DOI: 10.1038/nature19757] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 08/15/2016] [Indexed: 01/07/2023]
Abstract
In Gram-negative bacteria, outer membrane transporters import nutrients by coupling to an inner membrane protein complex called the Ton complex. The Ton complex consists of TonB, ExbB, and ExbD, and uses the proton motive force at the inner membrane to transduce energy to the outer membrane via TonB. Here, we structurally characterize the Ton complex from Escherichia coli using X-ray crystallography, electron microscopy, double electron-electron resonance (DEER) spectroscopy, and crosslinking. Our results reveal a stoichiometry consisting of a pentamer of ExbB, a dimer of ExbD, and at least one TonB. Electrophysiology studies show that the Ton subcomplex forms pH-sensitive cation-selective channels and provide insight into the mechanism by which it may harness the proton motive force to produce energy.
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Affiliation(s)
- Hervé Celia
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UMR7255 CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, 13402 Marseille Cedex 20, France,National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, 20892
| | - Nicholas Noinaj
- Markey Center for Structural Biology, Department of Biological Sciences, and the Purdue Institute for Inflammation, Immunology and Infectious Diseases, Purdue University, West Lafayette, Indiana, 47907,Correspondence and requests for materials should be addressed to N.N. (), R.L. () or S.K.B. ()
| | - Stanislav D. Zakharov
- Markey Center for Structural Biology, Department of Biological Sciences, and the Purdue Institute for Inflammation, Immunology and Infectious Diseases, Purdue University, West Lafayette, Indiana, 47907
| | - Enrica Bordignon
- Fachbereich Physik, Freie Universität, 14195 Berlin, Germany,Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, 45810 Bochum, Germany
| | - Istvan Botos
- National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, 20892
| | - Monica Santamaria
- Departamento de Cirugia Experimental, Instituto de Investigacion Hospital La Paz (IdiPAZ), Paseo de la Castellana 261, 28046 Madrid, Spain
| | - Travis J. Barnard
- National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, 20892
| | - William A. Cramer
- Markey Center for Structural Biology, Department of Biological Sciences, and the Purdue Institute for Inflammation, Immunology and Infectious Diseases, Purdue University, West Lafayette, Indiana, 47907
| | - Roland Lloubes
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, UMR7255 CNRS/Aix-Marseille Université, Institut de Microbiologie de la Méditerranée, 13402 Marseille Cedex 20, France,Correspondence and requests for materials should be addressed to N.N. (), R.L. () or S.K.B. ()
| | - Susan K. Buchanan
- National Institute of Diabetes & Digestive & Kidney Diseases, Bethesda, Maryland, 20892,Correspondence and requests for materials should be addressed to N.N. (), R.L. () or S.K.B. ()
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Abdelhamed H, Lu J, Lawrence ML, Karsi A. Involvement of tolQ and tolR genes in Edwardsiella ictaluri virulence. Microb Pathog 2016; 100:90-94. [PMID: 27622343 DOI: 10.1016/j.micpath.2016.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 09/09/2016] [Indexed: 10/21/2022]
Abstract
Edwardsiella ictaluri is a Gram-negative intracellular facultative pathogen causing enteric septicemia of channel catfish (ESC). The Tol system, consisting of four envelope proteins TolQ, TolR, TolA, and TolB, are required for colicin import and contributes to bacterial virulence in several pathogenic bacteria. However, the Tol system and its importance in E. ictaluri virulence have not been investigated. Here we present construction and evaluation of the E. ictaluri TolQ, TolR and TolQR mutants (EiΔtolQ, EiΔtolR, and EiΔtolQR). The Tol mutants were developed using in-frame gene deletion and their attenuation and vaccine efficacy were determined in catfish fingerlings. The EiΔtolQ, EiΔtolR, and EiΔtolQR mutants showed reduced virulence in catfish (28.93%, 19.70%, and 39.82% mortality, respectively) compared to wild type (46.91% mortality). Further, vaccination with these mutants protected catfish against subsequent wild-type infection. This study suggests that the Tol system contributes to E. ictaluri virulence in catfish.
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Affiliation(s)
- Hossam Abdelhamed
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS 39762, USA
| | - Jingjun Lu
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS 39762, USA
| | - Mark L Lawrence
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS 39762, USA
| | - Attila Karsi
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, MS 39762, USA.
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48
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Kosciow K, Domin C, Schweiger P, Deppenmeier U. Extracellular targeting of an active endoxylanase by a TolB negative mutant of Gluconobacter oxydans. ACTA ACUST UNITED AC 2016; 43:989-99. [DOI: 10.1007/s10295-016-1770-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/26/2016] [Indexed: 01/28/2023]
Abstract
Abstract
Gluconobacter (G.) oxydans strains have great industrial potential due to their ability to incompletely oxidize a wide range of carbohydrates. But there is one major limitation preventing their full production potential. Hydrolysis of polysaccharides is not possible because extracellular hydrolases are not encoded in the genome of Gluconobacter species. Therefore, as a first step for the generation of exoenzyme producing G. oxydans, a leaky outer membrane mutant was created by deleting the TolB encoding gene gox1687. As a second step the xynA gene encoding an endo-1,4-β-xylanase from Bacillus subtilis was expressed in G. oxydans ΔtolB. More than 70 % of the total XynA activity (0.91 mmol h−1 l culture−1) was detected in the culture supernatant of the TolB mutant and only 10 % of endoxylanase activity was observed in the supernatant of G. oxydans xynA. These results showed that a G. oxydans strain with an increased substrate spectrum that is able to use the renewable polysaccharide xylan as a substrate to produce the prebiotic compounds xylobiose and xylooligosaccharides was generated. This is the first report about the combination of the process of incomplete oxidation with the degradation of renewable organic materials from plants for the production of value-added products.
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Affiliation(s)
- Konrad Kosciow
- grid.10388.32 0000000122403300 Institute of Microbiology and Biotechnology University of Bonn Meckenheimer Allee 168 53115 Bonn Germany
| | - Claudia Domin
- grid.10388.32 0000000122403300 Institute of Microbiology and Biotechnology University of Bonn Meckenheimer Allee 168 53115 Bonn Germany
| | - Paul Schweiger
- grid.260126.1 0000000107458995 Biology Department Missouri State University 901 S. National Ave 65897 Springfield MO USA
| | - Uwe Deppenmeier
- grid.10388.32 0000000122403300 Institute of Microbiology and Biotechnology University of Bonn Meckenheimer Allee 168 53115 Bonn Germany
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49
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Spain EM, Núñez ME, Kim HJ, Taylor RJ, Thomas N, Wengen MB, Dalleska NF, Bromley JP, Schermerhorn KH, Ferguson MA. Identification and differential production of ubiquinone-8 in the bacterial predator Bdellovibrio bacteriovorus. Res Microbiol 2016; 167:413-23. [PMID: 27106259 DOI: 10.1016/j.resmic.2016.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 01/16/2016] [Accepted: 04/02/2016] [Indexed: 01/04/2023]
Abstract
Bdellovibrio bacteriovorus 109J, a predatory bacterium with potential as a bacterial control agent, can exist in several lifestyles that differ both in predatory capacity and color. We determined that levels of ubiquinone-8 contribute to the distinctive but variable yellow color of different types of Bdellovibrio cells. Steady-state ubiquinone-8 concentrations did not differ markedly between conventional predatory and host-independent B. bacteriovorus despite upregulation of a suite of ubiquinone-8 synthesis genes in host-independent cells. In contrast, in spatially organized B. bacteriovorus films, the yellow inner regions contain significantly higher ubiquinone-8 concentrations than the off-white outer regions. Correspondingly, RT-PCR analysis reveals that the inner region, previously shown to consist primarily of active predators, clearly expresses two ubiquinone biosynthesis genes, while the outer region, composed mainly of quiescent or stalled bdelloplasts, expresses those genes weakly or not at all. Moreover, B. bacteriovorus cells in the inner region of week-old interfacial films, which are phenotypically attack-phase, have much higher UQ8 levels than regular attack-phase bdellovibrios, most likely because their "trapped" state prevents a high expenditure of energy to power flagellar motion.
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Affiliation(s)
- Eileen M Spain
- Department of Chemistry, Occidental College, 1600 Campus Rd, Los Angeles, CA 90041, USA.
| | - Megan E Núñez
- Department of Chemistry, Wellesley College, 106 Central St. Wellesley, MA 02481, USA.
| | - Hyeong-Jin Kim
- Department of Chemistry, Occidental College, 1600 Campus Rd, Los Angeles, CA 90041, USA.
| | - Ryan J Taylor
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Nicholas Thomas
- Department of Chemistry, Occidental College, 1600 Campus Rd, Los Angeles, CA 90041, USA.
| | - Michael B Wengen
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Nathan F Dalleska
- Environmental Analysis Center, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
| | - Joseph P Bromley
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Kimberly H Schermerhorn
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
| | - Megan A Ferguson
- Department of Chemistry, State University of New York at New Paltz, 1 Hawk Drive, New Paltz, NY 12561, USA.
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50
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Mitra S, Sinha R, Mitobe J, Koley H. Development of a cost-effective vaccine candidate with outer membrane vesicles of a tolA-disrupted Shigella boydii strain. Vaccine 2016; 34:1839-46. [PMID: 26878295 DOI: 10.1016/j.vaccine.2016.02.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/20/2016] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
Abstract
Our previous studies on outer membrane vesicles based vaccine development against shigellosis, revealed the inability of Shigella to release significant amount of vesicles naturally, during growth. Disruption of tolA, one of the genes of the Tol-Pal system of Gram negative bacterial membrane, has increased the vesicle release rate of a Shigella boydii type 4 strain to approximately 60% higher. We also noticed the vesicles, released from tolA-disrupted strain captured more OmpA protein and lipopolysaccharide, compared to the vesicles released from its wild type prototype. Six to seven weeks old BALB/c mice, immunized with 25 μg of three oral doses of the vesicles, released by tolA mutant, conferred 100% protection against lethal homologous challenge through nasal route, compared to only 60% protection after the same dose of wild type immunogen. Mice, immunized with the vesicles from tolA-mutant, manifested significant secretion of mucosal IgG and IgA. A sharp and significant response of pro-inflammatory cytokines (TNF-α, IL-6, IFN-γ) were also observed in the lung lavage of these groups of mice, within 6h post challenge; but at 24h, these inflammatory cytokines showed the sign of subsidence and the system was taken over by the release of anti-inflammatory cytokines (IL-4 and IL-10). Studies with naïve peritoneal macrophages, proved further, the potency of these vesicles to stimulate nitric oxide and TNF-α, IL-12p70, IL-6 and IL-10 productions in-vitro. The ability of these vesicles to trigger polarization of CD4(+) T cells toward Th1 adaptive immune response, had also been observed along with the presence of anti-inflammatory cytokines in the system. Our study demonstrated, the vesicles from tolA-disrupted Shigella were able to suppress Shigella-mediated inflammation in the host and could balance between inflammation and anti-inflammation, promoting better survival and health of the infected mice. Outer membrane vesicles from tolA-mutant, could be a potential cost-effective vaccine candidate against shigellosis.
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Affiliation(s)
- Soma Mitra
- Division of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan; Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Ritam Sinha
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India
| | - Jiro Mitobe
- Division of Bacteriology I, National Institute of Infectious Diseases, Tokyo, Japan
| | - Hemanta Koley
- Division of Bacteriology, National Institute of Cholera and Enteric Diseases, Kolkata, India.
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