1
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Gigon L, Müller P, Haenni B, Iacovache I, Barbo M, Gosheva G, Yousefi S, Soragni A, von Ballmoos C, Zuber B, Simon HU. Membrane damage by MBP-1 is mediated by pore formation and amplified by mtDNA. Cell Rep 2024; 43:114084. [PMID: 38583154 DOI: 10.1016/j.celrep.2024.114084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/28/2023] [Accepted: 03/25/2024] [Indexed: 04/09/2024] Open
Abstract
Eosinophils play a crucial role in host defense while also contributing to immunopathology through the release of inflammatory mediators. Characterized by distinctive cytoplasmic granules, eosinophils securely store and rapidly release various proteins exhibiting high toxicity upon extracellular release. Among these, major basic protein 1 (MBP-1) emerges as an important mediator in eosinophil function against pathogens and in eosinophil-associated diseases. While MBP-1 targets both microorganisms and host cells, its precise mechanism remains elusive. We demonstrate that formation of small pores by MBP-1 in lipid bilayers induces membrane permeabilization and disrupts potassium balance. Additionally, we reveal that mitochondrial DNA (mtDNA) present in eosinophil extracellular traps (EETs) amplifies MBP-1 toxic effects, underscoring the pivotal role of mtDNA in EETs. Furthermore, we present evidence indicating that absence of CpG methylation in mtDNA contributes to the regulation of MBP-1-mediated toxicity. Taken together, our data suggest that the mtDNA scaffold within extracellular traps promotes MBP-1 toxicity.
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Affiliation(s)
- Lea Gigon
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland
| | - Philipp Müller
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Beat Haenni
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland
| | - Maruša Barbo
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland; Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Gordana Gosheva
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland; Faculty of Pharmacy, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Shida Yousefi
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland
| | - Alice Soragni
- Department of Orthopedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Christoph von Ballmoos
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland
| | - Hans-Uwe Simon
- Institute of Pharmacology, University of Bern, 3010 Bern, Switzerland; Institute of Biochemistry, Brandenburg Medical School, 16816 Neuruppin, Germany.
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2
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Thiede J, Rothenbühler S, Iacovache I, Langenegger SM, Zuber B, Häner R. Supramolecular assembly of pyrene-DNA conjugates: influence of pyrene substitution pattern and implications for artificial LHCs. Org Biomol Chem 2023; 21:7908-7912. [PMID: 37750811 PMCID: PMC10566252 DOI: 10.1039/d3ob01375h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 09/20/2023] [Indexed: 09/27/2023]
Abstract
The supramolecular self-assembly of pyrene-DNA conjugates into nanostructures is presented. DNA functionalized with different types of pyrene isomers at the 3'-end self-assemble into nano-objects. The shape of the nanostructures is influenced by the type of pyrene isomer appended to the DNA. Multilamellar vesicles are observed with the 1,6- and 1,8-isomers, whereas conjugates of the 2,7-isomer exclusively assemble into spherical nanoparticles. Self-assembled nano-spheres obtained with the 2,7-dialkynyl pyrene isomer were used for the construction of an artificial light-harvesting complex (LHC) in combination with Cy3 as the energy acceptor.
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Affiliation(s)
- Jan Thiede
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Simon Rothenbühler
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Simon M Langenegger
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Robert Häner
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
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3
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Bruggisser J, Iacovache I, Musson SC, Degiacomi MT, Posthaus H, Zuber B. Cryo-EM structure of the octameric pore of Clostridium perfringens β-toxin. EMBO Rep 2022; 23:e54856. [PMID: 36215680 PMCID: PMC9724662 DOI: 10.15252/embr.202254856] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 09/05/2022] [Accepted: 09/14/2022] [Indexed: 12/12/2022] Open
Abstract
Clostridium perfringens is one of the most widely distributed and successful pathogens producing an impressive arsenal of toxins. One of the most potent toxins produced is the C. perfringens β-toxin (CPB). This toxin is the main virulence factor of type C strains. We describe the cryo-electron microscopy (EM) structure of CPB oligomer. We show that CPB forms homo-octameric pores like the hetero-oligomeric pores of the bi-component leukocidins, with important differences in the receptor binding region and the N-terminal latch domain. Intriguingly, the octameric CPB pore complex contains a second 16-stranded β-barrel protrusion atop of the cap domain that is formed by the N-termini of the eight protomers. We propose that CPB, together with the newly identified Epx toxins, is a member a new subclass of the hemolysin-like family. In addition, we show that the β-barrel protrusion domain can be modified without affecting the pore-forming ability, thus making the pore particularly attractive for macromolecule sensing and nanotechnology. The cryo-EM structure of the octameric pore of CPB will facilitate future developments in both nanotechnology and basic research.
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Affiliation(s)
- Julia Bruggisser
- Institute of Animal Pathology, Vetsuisse‐FacultyUniversity of BernBernSwitzerland
| | - Ioan Iacovache
- Institute of Anatomy, Medical FacultyUniversity of BernBernSwitzerland
| | | | | | - Horst Posthaus
- Institute of Animal Pathology, Vetsuisse‐FacultyUniversity of BernBernSwitzerland
| | - Benoît Zuber
- Institute of Anatomy, Medical FacultyUniversity of BernBernSwitzerland
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4
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Rothenbühler S, Gonzalez A, Iacovache I, Langenegger SM, Zuber B, Häner R. Tetraphenylethylene-DNA conjugates: influence of sticky ends and DNA sequence length on the supramolecular assembly of AIE-active vesicles. Org Biomol Chem 2022; 20:3703-3707. [PMID: 35262542 PMCID: PMC9092531 DOI: 10.1039/d2ob00357k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The supramolecular assembly of DNA conjugates, functionalized with tetraphenylethylene (TPE) sticky ends, into vesicular structures is described. The aggregation-induced emission (AIE) active TPE units allow monitoring the assembly process by fluorescence spectroscopy. The number of TPE modifications in the overhangs of the conjugates influences the supramolecular assembly behavior. A minimum of two TPE residues on each end are required to ensure a well-defined assembly process. The design of the presented DNA-based nanostructures offers tailored functionalization with applications in DNA nanotechnology. The supramolecular assembly of tetraphenylethylene (TPE)–DNA conjugates is presented. The length of the TPE sticky ends exerts a pronounced effect on the formation of aggregation-induced emission (AIE)-active vesicles.![]()
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Affiliation(s)
- Simon Rothenbühler
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Adrian Gonzalez
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Simon M Langenegger
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Robert Häner
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland.
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5
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Schönfeldová T, Okur HI, Vezočnik V, Iacovache I, Cao C, Dal Peraro M, Maček P, Zuber B, Roke S. Ultrasensitive Label-Free Detection of Protein-Membrane Interaction Exemplified by Toxin-Liposome Insertion. J Phys Chem Lett 2022; 13:3197-3201. [PMID: 35377651 PMCID: PMC9014461 DOI: 10.1021/acs.jpclett.1c04011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Measuring the high-affinity binding of proteins to liposome membranes remains a challenge. Here, we show an ultrasensitive and direct detection of protein binding to liposome membranes using high throughput second harmonic scattering (SHS). Perfringolysin O (PFO), a pore-forming toxin, with a highly membrane selective insertion into cholesterol-rich membranes is used. PFO inserts only into liposomes with a cholesterol concentration >30%. Twenty mole-percent cholesterol results in neither SHS-signal deviation nor pore formation as seen by cryo-electron microscopy of PFO and liposomes. PFO inserts into cholesterol-rich membranes of large unilamellar vesicles in an aqueous solution with Kd = (1.5 ± 0.2) × 10-12 M. Our results demonstrate a promising approach to probe protein-membrane interactions below sub-picomolar concentrations in a label-free and noninvasive manner on 3D systems. More importantly, the volume of protein sample is ultrasmall (<10 μL). These findings enable the detection of low-abundance proteins and their interaction with membranes.
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Affiliation(s)
- T. Schönfeldová
- Laboratory
for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI),
School of Engineering (STI), École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - H. I. Okur
- Laboratory
for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI),
School of Engineering (STI), École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
- Department
of Chemistry and National Nanotechnology Research Center (UNAM), Bilkent University, 06800 Ankara, Turkey
| | - V. Vezočnik
- Department
of Biology, Biotechnical Faculty, University
of Ljubljana, Jamnikarjeva 101, Ljubljana 1000, Slovenia
| | - I. Iacovache
- Institute
of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - C. Cao
- Institute
of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - M. Dal Peraro
- Institute
of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - P. Maček
- Department
of Biology, Biotechnical Faculty, University
of Ljubljana, Jamnikarjeva 101, Ljubljana 1000, Slovenia
| | - B. Zuber
- Institute
of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - S. Roke
- Laboratory
for fundamental BioPhotonics (LBP), Institute of Bio-engineering (IBI),
School of Engineering (STI), École
Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
- Institute
of Materials Science (IMX) and Lausanne Centre for Ultrafast Science
(LACUS), École Polytechnique Fédérale
de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
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6
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Rothenbühler S, Iacovache I, Langenegger SM, Zuber B, Häner R. Complex DNA Architectonics─Self-Assembly of Amphiphilic Oligonucleotides into Ribbons, Vesicles, and Asterosomes. Bioconjug Chem 2022; 34:70-77. [PMID: 35357155 PMCID: PMC9854621 DOI: 10.1021/acs.bioconjchem.2c00077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The precise arrangement of structural subunits is a key factor for the proper shape and function of natural and artificial supramolecular assemblies. In DNA nanotechnology, the geometrically well-defined double-stranded DNA scaffold serves as an element of spatial control for the precise arrangement of functional groups. Here, we describe the supramolecular assembly of chemically modified DNA hybrids into diverse types of architectures. An amphiphilic DNA duplex serves as the sole structural building element of the nanosized supramolecular structures. The morphology of the assemblies is governed by a single subunit of the building block. The chemical nature of this subunit, i.e., polyethylene glycols of different chain length or a carbohydrate moiety, exerts a dramatic influence on the architecture of the assemblies. Cryo-electron microscopy revealed the arrangement of the individual DNA duplexes within the different constructs. Thus, the morphology changes from vesicles to ribbons with increasing length of a linear polyethylene glycol. Astoundingly, attachment of a N-acetylgalactosamine carbohydrate to the DNA duplex moiety produces an unprecedented type of star-shaped architecture. The novel DNA architectures presented herein imply an extension of the current concept of DNA materials and shed new light on the fast-growing field of DNA nanotechnology.
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Affiliation(s)
- Simon Rothenbühler
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Ioan Iacovache
- Institute
of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Simon M. Langenegger
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
| | - Benoît Zuber
- Institute
of Anatomy, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
| | - Robert Häner
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland,
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7
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Milijaš Jotić M, Panevska A, Iacovache I, Kostanjšek R, Mravinec M, Skočaj M, Zuber B, Pavšič A, Razinger J, Modic Š, Trenti F, Guella G, Sepčić K. Dissecting Out the Molecular Mechanism of Insecticidal Activity of Ostreolysin A6/Pleurotolysin B Complexes on Western Corn Rootworm. Toxins (Basel) 2021; 13:toxins13070455. [PMID: 34209983 PMCID: PMC8310357 DOI: 10.3390/toxins13070455] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 02/04/2023] Open
Abstract
Ostreolysin A6 (OlyA6) is a protein produced by the oyster mushroom (Pleurotus ostreatus). It binds to membrane sphingomyelin/cholesterol domains, and together with its protein partner, pleurotolysin B (PlyB), it forms 13-meric transmembrane pore complexes. Further, OlyA6 binds 1000 times more strongly to the insect-specific membrane sphingolipid, ceramide phosphoethanolamine (CPE). In concert with PlyB, OlyA6 has potent and selective insecticidal activity against the western corn rootworm. We analysed the histological alterations of the midgut wall columnar epithelium of western corn rootworm larvae fed with OlyA6/PlyB, which showed vacuolisation of the cell cytoplasm, swelling of the apical cell surface into the gut lumen, and delamination of the basal lamina underlying the epithelium. Additionally, cryo-electron microscopy was used to explore the membrane interactions of the OlyA6/PlyB complex using lipid vesicles composed of artificial lipids containing CPE, and western corn rootworm brush border membrane vesicles. Multimeric transmembrane pores were formed in both vesicle preparations, similar to those described for sphingomyelin/cholesterol membranes. These results strongly suggest that the molecular mechanism of insecticidal action of OlyA6/PlyB arises from specific interactions of OlyA6 with CPE, and the consequent formation of transmembrane pores in the insect midgut.
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Affiliation(s)
- Matej Milijaš Jotić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Anastasija Panevska
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (I.I.); (B.Z.)
| | - Rok Kostanjšek
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Martina Mravinec
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Matej Skočaj
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, 3012 Bern, Switzerland; (I.I.); (B.Z.)
| | - Ana Pavšič
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
| | - Jaka Razinger
- Agricultural Institute of Slovenia, 1000 Ljubljana, Slovenia; (J.R.); (Š.M.)
| | - Špela Modic
- Agricultural Institute of Slovenia, 1000 Ljubljana, Slovenia; (J.R.); (Š.M.)
| | - Francesco Trenti
- Bioorganic Chemistry Laboratory, Department of Physics, University of Trento, 38123 Trento, Italy; (F.T.); (G.G.)
| | - Graziano Guella
- Bioorganic Chemistry Laboratory, Department of Physics, University of Trento, 38123 Trento, Italy; (F.T.); (G.G.)
| | - Kristina Sepčić
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia; (M.M.J.); (A.P.); (R.K.); (M.M.); (M.S.); (A.P.)
- Correspondence: ; Tel.: +386-1-320-3419
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8
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Reuther J, Schneider L, Iacovache I, Pircher A, Gharib WH, Zuber B, Polacek N. A small ribosome-associated ncRNA globally inhibits translation by restricting ribosome dynamics. RNA Biol 2021; 18:2617-2632. [PMID: 34121604 PMCID: PMC8632108 DOI: 10.1080/15476286.2021.1935573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ribosome-associated non-coding RNAs (rancRNAs) have been recognized as an emerging class of regulatory molecules capable of fine-tuning translation in all domains of life. RancRNAs are ideally suited for allowing a swift response to changing environments and are therefore considered pivotal during the first wave of stress adaptation. Previously, we identified an mRNA-derived 18 nucleotides long rancRNA (rancRNA_18) in Saccharomyces cerevisiae that rapidly downregulates protein synthesis during hyperosmotic stress. However, the molecular mechanism of action remained enigmatic. Here, we combine biochemical, genetic, transcriptome-wide and structural evidence, thus revealing rancRNA_18 as global translation inhibitor by targeting the E-site region of the large ribosomal subunit. Ribosomes carrying rancRNA_18 possess decreased affinity for A-site tRNA and impaired structural dynamics. Cumulatively, these discoveries reveal the mode of action of a rancRNA involved in modulating protein biosynthesis at a thus far unequalled precision.
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Affiliation(s)
- Julia Reuther
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Lukas Schneider
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Andreas Pircher
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.,Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Walid H Gharib
- Interfaculty Bioinformatics Unit, University of Bern, Bern, Switzerland
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Bern, Switzerland
| | - Norbert Polacek
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
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9
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Abstract
The self-assembly of DNA hybrids possessing tetraphenylethylene sticky ends at both sides into vesicular architectures in aqueous medium is demonstrated. Cryo-electron microscopy reveals the formation of different types of morphologies from the amphiphilic DNA-hybrids. Depending on the conditions, either an extended (sheet-like) or a compact (columnar) alignment of the DNA hybrids is observed. The different modes of DNA arrangement lead to the formation of vesicles appearing either as prolate ellipsoids (type I) or as spheres (type II). The type of packing has a significant effect on the accessibility of the DNA, as evidenced by intercalation and light-harvesting experiments. Only the vesicles exhibiting the sheet-like DNA alignment are accessible for intercalation by ethidium bromide or for the integration of chromophore-labelled DNA via a strand exchange process. The dynamic nature of type I vesicles enables their elaboration into artificial light-harvesting complexes by DNA-guided introduction of Cy3-acceptor chromophores. DNA-constructed vesicles of the kind shown here represent versatile intermediates that are amenable to further modification for tailored nanotechnology applications.
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Affiliation(s)
- Simon Rothenbühler
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH - 3012 Bern, Switzerland.
| | - Ioan Iacovache
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH - 3012 Bern, Switzerland.
| | - Simon M Langenegger
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH - 3012 Bern, Switzerland.
| | - Benoît Zuber
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH - 3012 Bern, Switzerland.
| | - Robert Häner
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH - 3012 Bern, Switzerland.
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10
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Poghosyan E, Iacovache I, Faltova L, Leitner A, Yang P, Diener DR, Aebersold R, Zuber B, Ishikawa T. The structure and symmetry of the radial spoke protein complex in Chlamydomonas flagella. J Cell Sci 2020; 133:jcs245233. [PMID: 32694165 DOI: 10.1242/jcs.245233] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/25/2020] [Indexed: 12/27/2022] Open
Abstract
The radial spoke is a key element in a transducer apparatus controlling the motility of eukaryotic cilia. The transduction biomechanics is a long-standing question in cilia biology. The radial spoke has three regions - a spoke head, a bifurcated neck and a stalk. Although the neck and the stalk are asymmetric, twofold symmetry of the head has remained controversial. In this work we used single particle cryo-electron microscopy (cryo-EM) analysis to generate a 3D structure of the whole radial spoke at unprecedented resolution. We show the head region at 15 Å (1.5 nm) resolution and confirm twofold symmetry. Using distance constraints generated by cross-linking mass spectrometry, we locate two components, RSP2 and RSP4, at the head and neck regions. Our biophysical analysis of isolated RSP4, RSP9, and RSP10 affirmed their oligomeric state. Our results enable us to redefine the boundaries of the regions and propose a model of organization of the radial spoke component proteins.
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Affiliation(s)
- Emiliya Poghosyan
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
- ETH Zurich, Department of Biology, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
| | - Ioan Iacovache
- University of Bern, Institute of Anatomy, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Lenka Faltova
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Alexander Leitner
- ETH Zurich, Department of Biology, Institute of Molecular Systems Biology, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Pinfen Yang
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53233, USA
| | - Dennis R Diener
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Ruedi Aebersold
- ETH Zurich, Department of Biology, Institute of Molecular Systems Biology, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
- University of Zurich, Faculty of Science, Rämistrasse 71, 8006 Zürich, Switzerland
| | - Benoit Zuber
- University of Bern, Institute of Anatomy, Baltzerstrasse 2, 3012 Bern, Switzerland
| | - Takashi Ishikawa
- Paul Scherrer Institute, Department of Biology and Chemistry, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
- ETH Zurich, Department of Biology, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Switzerland
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11
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Drücker P, Iacovache I, Bachler S, Zuber B, Babiychuk EB, Dittrich PS, Draeger A. Membrane deformation and layer-by-layer peeling of giant vesicles induced by the pore-forming toxin pneumolysin. Biomater Sci 2019; 7:3693-3705. [DOI: 10.1039/c9bm00134d] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Membranes under attack by the pore-forming toxin pneumolysin reveal a hitherto unknown layer-by-layer peeling mechanism and disclose the multilamellar structure.
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Affiliation(s)
- Patrick Drücker
- Department of Biosystems Science and Engineering
- ETH Zurich
- 4058 Basel
- Switzerland
- Department of Cell Biology
| | - Ioan Iacovache
- Laboratory of Experimental Morphology
- Institute of Anatomy
- University of Bern
- 3000 Bern 9
- Switzerland
| | - Simon Bachler
- Department of Biosystems Science and Engineering
- ETH Zurich
- 4058 Basel
- Switzerland
| | - Benoît Zuber
- Laboratory of Experimental Morphology
- Institute of Anatomy
- University of Bern
- 3000 Bern 9
- Switzerland
| | - Eduard B. Babiychuk
- Department of Cell Biology
- Institute of Anatomy
- University of Bern
- 3000 Bern 9
- Switzerland
| | - Petra S. Dittrich
- Department of Biosystems Science and Engineering
- ETH Zurich
- 4058 Basel
- Switzerland
| | - Annette Draeger
- Department of Cell Biology
- Institute of Anatomy
- University of Bern
- 3000 Bern 9
- Switzerland
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12
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Bischofberger M, Iacovache I, Boss D, Naef F, van der Goot FG, Molina N. Revealing Assembly of a Pore-Forming Complex Using Single-Cell Kinetic Analysis and Modeling. Biophys J 2016; 110:1574-1581. [PMID: 27074682 PMCID: PMC4833779 DOI: 10.1016/j.bpj.2016.02.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/15/2016] [Accepted: 02/22/2016] [Indexed: 11/21/2022] Open
Abstract
Many biological processes depend on the sequential assembly of protein complexes. However, studying the kinetics of such processes by direct methods is often not feasible. As an important class of such protein complexes, pore-forming toxins start their journey as soluble monomeric proteins, and oligomerize into transmembrane complexes to eventually form pores in the target cell membrane. Here, we monitored pore formation kinetics for the well-characterized bacterial pore-forming toxin aerolysin in single cells in real time to determine the lag times leading to the formation of the first functional pores per cell. Probabilistic modeling of these lag times revealed that one slow and seven equally fast rate-limiting reactions best explain the overall pore formation kinetics. The model predicted that monomer activation is the rate-limiting step for the entire pore formation process. We hypothesized that this could be through release of a propeptide and indeed found that peptide removal abolished these steps. This study illustrates how stochasticity in the kinetics of a complex process can be exploited to identify rate-limiting mechanisms underlying multistep biomolecular assembly pathways.
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Affiliation(s)
- Mirko Bischofberger
- Global Health Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; The Institute of Bioengineering, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ioan Iacovache
- Global Health Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Daniel Boss
- The Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Felix Naef
- The Institute of Bioengineering, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - F Gisou van der Goot
- Global Health Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Nacho Molina
- Center of Synthetic and Systems Biology, University of Edinburgh, Edinburgh, United Kingdom.
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13
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Degiacomi MT, Iacovache I, Pernot L, Chami M, Kudryashev M, Stahlberg H, van der Goot FG, Dal Peraro M. Molecular assembly of the aerolysin pore reveals a swirling membrane-insertion mechanism. Nat Chem Biol 2013; 9:623-9. [PMID: 23912165 DOI: 10.1038/nchembio.1312] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Accepted: 06/25/2013] [Indexed: 12/24/2022]
Abstract
Aerolysin is the founding member of a superfamily of β-pore-forming toxins whose pore structure is unknown. We have combined X-ray crystallography, cryo-EM, molecular dynamics and computational modeling to determine the structures of aerolysin mutants in their monomeric and heptameric forms, trapped at various stages of the pore formation process. A dynamic modeling approach based on swarm intelligence was applied, whereby the intrinsic flexibility of aerolysin extracted from new X-ray structures was used to fully exploit the cryo-EM spatial restraints. Using this integrated strategy, we obtained a radically new arrangement of the prepore conformation and a near-atomistic structure of the aerolysin pore, which is fully consistent with all of the biochemical data available so far. Upon transition from the prepore to pore, the aerolysin heptamer shows a unique concerted swirling movement, accompanied by a vertical collapse of the complex, ultimately leading to the insertion of a transmembrane β-barrel.
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Affiliation(s)
- Matteo T Degiacomi
- 1] Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland. [2] [3]
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14
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Abstract
Organisms from all kingdoms produce pore-forming proteins, with the best-characterized being of bacterial origin. The last decade of research has revealed that the channels formed by these proteins can be very diverse, thus differentially affecting target cell-membrane permeability and consequent cellular outcome. The responses to these toxins are also extremely diverse due to multiple downstream effects of pore-induced changes in ion balance. Determining the secondary effects of pore-forming toxins is essential to understand their contribution to infection.
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Affiliation(s)
- Mirko Bischofberger
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 15, CH-1015 Lausanne, Switzerland
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15
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Dal Peraro M, Degiacomi M, Iacovache I, van de Goot G. Unraveling the Assembly of Large Macromolecular Machines by Integrating Computational Techniques with Experimental Data. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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16
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Opota O, Vallet-Gély I, Vincentelli R, Kellenberger C, Iacovache I, Gonzalez MR, Roussel A, van der Goot FG, Lemaitre B. Monalysin, a novel ß-pore-forming toxin from the Drosophila pathogen Pseudomonas entomophila, contributes to host intestinal damage and lethality. PLoS Pathog 2011; 7:e1002259. [PMID: 21980286 PMCID: PMC3182943 DOI: 10.1371/journal.ppat.1002259] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/25/2011] [Indexed: 02/07/2023] Open
Abstract
Pseudomonas entomophila is an entomopathogenic bacterium that infects and kills Drosophila. P. entomophila pathogenicity is linked to its ability to cause irreversible damages to the Drosophila gut, preventing epithelium renewal and repair. Here we report the identification of a novel pore-forming toxin (PFT), Monalysin, which contributes to the virulence of P. entomophila against Drosophila. Our data show that Monalysin requires N-terminal cleavage to become fully active, forms oligomers in vitro, and induces pore-formation in artificial lipid membranes. The prediction of the secondary structure of the membrane-spanning domain indicates that Monalysin is a PFT of the ß-type. The expression of Monalysin is regulated by both the GacS/GacA two-component system and the Pvf regulator, two signaling systems that control P. entomophila pathogenicity. In addition, AprA, a metallo-protease secreted by P. entomophila, can induce the rapid cleavage of pro-Monalysin into its active form. Reduced cell death is observed upon infection with a mutant deficient in Monalysin production showing that Monalysin plays a role in P. entomophila ability to induce intestinal cell damages, which is consistent with its activity as a PFT. Our study together with the well-established action of Bacillus thuringiensis Cry toxins suggests that production of PFTs is a common strategy of entomopathogens to disrupt insect gut homeostasis. Insects are potential reservoirs for microbes and ideal vectors for their transmission due to their motility and capacity to live in bacteria-rich environments. This is exemplified by fruit flies that live in rotting fruits and are capable of transmitting phytopathogenic bacteria. Insects are notably resistant to microbial infection allowing them to colonize these microbe-rich environments. To study how pathogenic bacteria disrupt gut homeostasis, we investigated the interactions between Drosophila and a newly identified entomopathogen, Pseudomonas entomophila. Ingestion of P. entomophila inflicts severe damage to the Drosophila intestine. How damages are inflicted, however, remains unknown. In this study, we identified a secreted protein that plays an important role in the damage inflicted by P. entomophila to the Drosophila gut. We showed that this protein is a pore-forming toxin (PFT) that we named Monalysin. Our study reveals that Monalysin oligomerizes into ring-like structures that form pores into the plasma membrane of target cells leading to the disruption of membrane permeability and cell death. Our work together with studies on the insecticidal Cry toxins produced by Bacillus thuringiensis suggests that production of PFTs is a common strategy of entomopathogenic bacteria to interfere with insect gut homeostasis.
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Affiliation(s)
- Onya Opota
- Global Health Institute, Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne, Switzerland
- * E-mail: (OO); (BL)
| | | | - Renaud Vincentelli
- Structural Immunology, AFMB UMR 6098 CNRS/UI/UII, Case 932, Marseille, France
| | | | - Ioan Iacovache
- Global Health Institute, Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne, Switzerland
| | - Manuel Rodrigo Gonzalez
- Global Health Institute, Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne, Switzerland
| | - Alain Roussel
- Structural Immunology, AFMB UMR 6098 CNRS/UI/UII, Case 932, Marseille, France
| | | | - Bruno Lemaitre
- Global Health Institute, Ecole Polytechnique Fédérale Lausanne (EPFL), Lausanne, Switzerland
- * E-mail: (OO); (BL)
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17
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Iacovache I, Degiacomi MT, Pernot L, Ho S, Schiltz M, Dal Peraro M, van der Goot FG. Dual chaperone role of the C-terminal propeptide in folding and oligomerization of the pore-forming toxin aerolysin. PLoS Pathog 2011; 7:e1002135. [PMID: 21779171 PMCID: PMC3136475 DOI: 10.1371/journal.ppat.1002135] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Accepted: 05/11/2011] [Indexed: 01/14/2023] Open
Abstract
Throughout evolution, one of the most ancient forms of aggression between cells or organisms has been the production of proteins or peptides affecting the permeability of the target cell membrane. This class of virulence factors includes the largest family of bacterial toxins, the pore-forming toxins (PFTs). PFTs are bistable structures that can exist in a soluble and a transmembrane state. It is unclear what drives biosynthetic folding towards the soluble state, a requirement that is essential to protect the PFT-producing cell. Here we have investigated the folding of aerolysin, produced by the human pathogen Aeromonas hydrophila, and more specifically the role of the C-terminal propeptide (CTP). By combining the predictive power of computational techniques with experimental validation using both structural and functional approaches, we show that the CTP prevents aggregation during biosynthetic folding. We identified specific residues that mediate binding of the CTP to the toxin. We show that the CTP is crucial for the control of the aerolysin activity, since it protects individual subunits from aggregation within the bacterium and later controls assembly of the quaternary pore-forming complex at the surface of the target host cell. The CTP is the first example of a C-terminal chain-linked chaperone with dual function. Many pathogenic bacteria produce proteins, called pore-forming toxins, designed to perforate the plasma membrane of target cells thus perturbing host cell integrity and functionality. It is, however, important that these toxins do not form pores in the producing bacterium. To prevent this, bacteria initially produce them in a soluble state. After being secreted by the bacterium, the toxin subsequently acquires – often through a multimerization step– the ability to insert into the membrane. Here we were interested in the mechanisms ensuring that the toxin initially folds into the soluble state. Using as an example aerolysin from the human pathogen Aeromonas hydrophila, we show that the bacterium produces the toxin with a C-terminal extension of about 45 amino acids that promotes the folding of the protein into the soluble state. We find that by mutating or removing this extension, the protein folds poorly or not at all. Addition of the peptide in trans however lead to partial recovery of activity suggesting that this extension promotes folding, and being intramolecular thus results in a very high effective concentration. In addition to this chaperone role for correctly folding the monomeric form of the toxin, the C-terminal peptide is also crucial for controlling the folding of the quaternary structure of the mature pore complex at the surface of the target host cell.
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Affiliation(s)
- Ioan Iacovache
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Matteo T. Degiacomi
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Lucile Pernot
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Sylvia Ho
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marc Schiltz
- Laboratoire de Cristallographie, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- * E-mail: (FGVDH); (MDP)
| | - F. Gisou van der Goot
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- * E-mail: (FGVDH); (MDP)
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18
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Szczesny P, Iacovache I, Muszewska A, Ginalski K, van der Goot FG, Grynberg M. Extending the aerolysin family: from bacteria to vertebrates. PLoS One 2011; 6:e20349. [PMID: 21687664 PMCID: PMC3110756 DOI: 10.1371/journal.pone.0020349] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Accepted: 04/29/2011] [Indexed: 11/18/2022] Open
Abstract
A number of bacterial virulence factors have been observed to adopt structures similar to that of aerolysin, the principal toxin of Aeromonas species. However, a comprehensive description of architecture and structure of the aerolysin-like superfamily has not been determined. In this study, we define a more compact aerolysin-like domain--or aerolysin fold--and show that this domain is far more widely spread than anticipated since it can be found throughout kingdoms. The aerolysin-fold could be found in very diverse domain and functional contexts, although a toxic function could often be assigned. Due to this diversity, the borders of the superfamily could not be set on a sequence level. As a border-defining member, we therefore chose pXO2-60--a protein from the pathogenic pXO2 plasmid of Bacillus anthracis. This fascinating protein, which harbors a unique ubiquitin-like fold domain at the C-terminus of the aerolysin-domain, nicely illustrates the diversity of the superfamily. Its putative role in the virulence of B. anthracis and its three dimensional model are discussed.
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Affiliation(s)
- Pawel Szczesny
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Experimental Plant Biology, University of Warsaw, Warsaw, Poland
| | - Ioan Iacovache
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Anna Muszewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Krzysztof Ginalski
- Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, Warsaw, Poland
| | - F. Gisou van der Goot
- Faculty of Life Sciences, Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Marcin Grynberg
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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19
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Dal Peraro M, Degiacomi M, Iacovache I, van der Goot G. Assembly and Function of Pore-Forming Toxin Aerolysin from Aeromonas Hydrophila. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.2312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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20
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Iacovache I, Bischofberger M, van der Goot FG. Structure and assembly of pore-forming proteins. Curr Opin Struct Biol 2010; 20:241-6. [PMID: 20172710 DOI: 10.1016/j.sbi.2010.01.013] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 01/13/2010] [Accepted: 01/25/2010] [Indexed: 11/17/2022]
Abstract
Pore-forming proteins (PFPs), involved in host-pathogen interactions, are produced as soluble, generally monomeric, proteins. To convert from the soluble to the transmembrane form, PFPs assemble, in the vicinity of the target membrane, into ring-like structures, which expose sufficient hydrophobicity to drive spontaneous bilayer insertion. Recent findings have highlighted two interesting aspects: (1) that pores form via similar overall mechanisms even if originating from vastly different structures and (2) specific folds found in PFPs can be found in widely different organisms, as distant as prokaryotes and mammals, highlighting that pore formation is an ancient form of attack that has been remarkably conserved.
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Affiliation(s)
- Ioan Iacovache
- Ecole Polytechnique Fédérale de Lausanne, Global Health Institute, Station 15, Lausanne, Switzerland
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21
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Iacovache I, Biasini M, Kowal J, Kukulski W, Chami M, van der Goot FG, Engel A, Rémigy HW. The 2DX robot: a membrane protein 2D crystallization Swiss Army knife. J Struct Biol 2009; 169:370-8. [PMID: 19963066 DOI: 10.1016/j.jsb.2009.12.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 11/07/2009] [Accepted: 12/02/2009] [Indexed: 11/27/2022]
Abstract
Among the state-of-the-art techniques that provide experimental information at atomic scale for membrane proteins, electron crystallography, atomic force microscopy and solid state NMR make use of two-dimensional crystals. We present a cyclodextrin-driven method for detergent removal implemented in a fully automated robot. The kinetics of the reconstitution processes is precisely controlled, because the detergent complexation by cyclodextrin is of stoichiometric nature. The method requires smaller volumes and lower protein concentrations than established 2D crystallization methods, making it possible to explore more conditions with the same amount of protein. The method yielded highly ordered 2D crystals diffracting to high resolution from the pore-forming toxin Aeromonas hydrophila aerolysin (2.9A), the plant aquaporin SoPIP2;1 (3.1A) and the human aquaporin-8 (hAQP8; 3.3A). This new method outperforms traditional 2D crystallization approaches in terms of accuracy, flexibility, throughput, and allows the usage of detergents having low critical micelle concentration (CMC), which stabilize the structure of membrane proteins in solution.
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Affiliation(s)
- Ioan Iacovache
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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22
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Iacovache I, van der Goot FG, Pernot L. Pore formation: an ancient yet complex form of attack. Biochim Biophys Acta 2008; 1778:1611-23. [PMID: 18298943 DOI: 10.1016/j.bbamem.2008.01.026] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 01/03/2008] [Accepted: 01/04/2008] [Indexed: 02/07/2023]
Abstract
Bacteria, as well as higher organisms such as sea anemones or earthworms, have developed sophisticated virulence factors such as the pore-forming toxins (PFTs) to mount their attack against the host. One of the most fascinating aspects of PFTs is that they can adopt a water-soluble form at the beginning of their lifetime and become an integral transmembrane protein in the membrane of the target cells. There is a growing understanding of the sequence of events and the various conformational changes undergone by these toxins in order to bind to the host cell surface, to penetrate the cell membranes and to achieve pore formation. These points will be addressed in this review.
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Affiliation(s)
- Ioan Iacovache
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Faculty of Life Sciences, Station 15, Lausanne, Switzerland
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23
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Iacovache I, Paumard P, Scheib H, Lesieur C, Sakai N, Matile S, Parker MW, van der Goot FG. A rivet model for channel formation by aerolysin-like pore-forming toxins. EMBO J 2006; 25:457-66. [PMID: 16424900 PMCID: PMC1383540 DOI: 10.1038/sj.emboj.7600959] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2005] [Accepted: 12/16/2005] [Indexed: 11/09/2022] Open
Abstract
The bacterial toxin aerolysin kills cells by forming heptameric channels, of unknown structure, in the plasma membrane. Using disulfide trapping and cysteine scanning mutagenesis coupled to thiol-specific labeling on lipid bilayers, we identify a loop that lines the channel. This loop has an alternating pattern of charged and uncharged residues, suggesting that the transmembrane region has a beta-barrel configuration, as observed for Staphylococcal alpha-toxin. Surprisingly, we found that the turn of the beta-hairpin is composed of a stretch of five hydrophobic residues. We show that this hydrophobic turn drives membrane insertion of the developing channel and propose that, once the lipid bilayer has been crossed, it folds back parallel to the plane of the membrane in a rivet-like fashion. This rivet-like conformation was modeled and sequence alignments suggest that such channel riveting may operate for many other pore-forming toxins.
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Affiliation(s)
- Ioan Iacovache
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Patrick Paumard
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Holger Scheib
- Department of Structural Biology, University of Geneva, Geneva, Switzerland
- Swiss Institute of Bioinformatics, University of Geneva, Geneva, Switzerland
- SBC Lab AG, Winkel, Switzerland
| | - Claire Lesieur
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Naomi Sakai
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Stefan Matile
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Michael W Parker
- Biota Structural Biology Laboratory, St Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - F Gisou van der Goot
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
- Department of Genetics & Microbiology, CMU, University of Geneva, 30 quai Ernest Ansermet, 1211 Geneva 4, Switzerland. Tel.: +41 22 379 5652; Fax: +41 22 379 5896; E-mail:
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25
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Tugulea L, Iacovache I. Chlorophyll a in liposomes--spectral and electrochemical studies. Cell Mol Biol Lett 2002; 7:302. [PMID: 12097972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Affiliation(s)
- Laura Tugulea
- Faculty of Physics, University of Bucharest, Department of Electricity and Biophysics, P.O.Box. MG-11, Bucharest-Magurele, 76900 Romania.
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