1
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Marini G, Poland B, Leininger C, Lukoyanova N, Spielbauer D, Barry JK, Altier D, Lum A, Scolaro E, Ortega CP, Yalpani N, Sandahl G, Mabry T, Klever J, Nowatzki T, Zhao JZ, Sethi A, Kassa A, Crane V, Lu AL, Nelson ME, Eswar N, Topf M, Saibil HR. Structural journey of an insecticidal protein against western corn rootworm. Nat Commun 2023; 14:4171. [PMID: 37443175 PMCID: PMC10344926 DOI: 10.1038/s41467-023-39891-7] [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: 01/12/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
The broad adoption of transgenic crops has revolutionized agriculture. However, resistance to insecticidal proteins by agricultural pests poses a continuous challenge to maintaining crop productivity and new proteins are urgently needed to replace those utilized for existing transgenic traits. We identified an insecticidal membrane attack complex/perforin (MACPF) protein, Mpf2Ba1, with strong activity against the devastating coleopteran pest western corn rootworm (WCR) and a novel site of action. Using an integrative structural biology approach, we determined monomeric, pre-pore and pore structures, revealing changes between structural states at high resolution. We discovered an assembly inhibition mechanism, a molecular switch that activates pre-pore oligomerization upon gut fluid incubation and solved the highest resolution MACPF pore structure to-date. Our findings demonstrate not only the utility of Mpf2Ba1 in the development of biotechnology solutions for protecting maize from WCR to promote food security, but also uncover previously unknown mechanistic principles of bacterial MACPF assembly.
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Affiliation(s)
- Guendalina Marini
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
- Centre for Structural Systems Biology (CSSB), Leibniz-Institut für Virologie (LIV), Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Brad Poland
- Corteva Agriscience, Johnston, IA, 50131, USA
| | - Chris Leininger
- Corteva Agriscience, Johnston, IA, 50131, USA
- Syngenta, Research Triangle Park, NC, 27709, USA
| | - Natalya Lukoyanova
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK
| | | | | | - Dan Altier
- Corteva Agriscience, Johnston, IA, 50131, USA
| | - Amy Lum
- Corteva Agriscience, Johnston, IA, 50131, USA
- Willow Biosciences, 319 N Bernardo Ave #4, Mountain View, CA, 94043, USA
| | | | - Claudia Pérez Ortega
- Corteva Agriscience, Johnston, IA, 50131, USA
- Hologic, Inc., 250 Campus Drive, Marlborough, MA, 01752, USA
| | - Nasser Yalpani
- Corteva Agriscience, Johnston, IA, 50131, USA
- Dept. of Biology, University of British Columbia Okanagan, 3187 University Way, Kelowna, BC, V1V 1V7, Canada
| | | | - Tim Mabry
- Corteva Agriscience, Ivesdale, IL, 61851, USA
| | | | | | | | - Amit Sethi
- Corteva Agriscience, Johnston, IA, 50131, USA
| | - Adane Kassa
- Corteva Agriscience, Johnston, IA, 50131, USA
| | | | - Albert L Lu
- Corteva Agriscience, Johnston, IA, 50131, USA
| | | | | | - Maya Topf
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK.
- Centre for Structural Systems Biology (CSSB), Leibniz-Institut für Virologie (LIV), Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany.
| | - Helen R Saibil
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London, WC1E 7HX, UK.
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2
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Ivanova ME, Lukoyanova N, Malhotra S, Topf M, Trapani JA, Voskoboinik I, Saibil HR. The pore conformation of lymphocyte perforin. SCIENCE ADVANCES 2022; 8:eabk3147. [PMID: 35148176 PMCID: PMC8836823 DOI: 10.1126/sciadv.abk3147] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 12/17/2021] [Indexed: 05/05/2023]
Abstract
Perforin is a pore-forming protein that facilitates rapid killing of pathogen-infected or cancerous cells by the immune system. Perforin is released from cytotoxic lymphocytes, together with proapoptotic granzymes, to bind to a target cell membrane where it oligomerizes and forms pores. The pores allow granzyme entry, which rapidly triggers the apoptotic death of the target cell. Here, we present a 4-Å resolution cryo-electron microscopy structure of the perforin pore, revealing previously unidentified inter- and intramolecular interactions stabilizing the assembly. During pore formation, the helix-turn-helix motif moves away from the bend in the central β sheet to form an intermolecular contact. Cryo-electron tomography shows that prepores form on the membrane surface with minimal conformational changes. Our findings suggest the sequence of conformational changes underlying oligomerization and membrane insertion, and explain how several pathogenic mutations affect function.
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Affiliation(s)
- Marina E. Ivanova
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
- Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Natalya Lukoyanova
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
| | - Sony Malhotra
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
- Scientific Computing Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Fermi Ave, Harwell, Didcot OX11 0QX, UK
| | - Maya Topf
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
- Centre for Structural Systems Biology, Leibniz-Institut für Experimentelle Virologie and Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Joseph A. Trapani
- Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia
| | - Ilia Voskoboinik
- Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia
| | - Helen R. Saibil
- Institute of Structural and Molecular Biology, Birkbeck, University of London, Malet St, London WC1E 7HX, UK
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Scott H, Huang W, Bann JG, Taylor DJ. Advances in structure determination by cryo-EM to unravel membrane-spanning pore formation. Protein Sci 2018; 27:1544-1556. [PMID: 30129169 PMCID: PMC6194281 DOI: 10.1002/pro.3454] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Revised: 06/10/2018] [Accepted: 06/11/2018] [Indexed: 01/03/2023]
Abstract
The beta pore-forming proteins (β-PFPs) are a large class of polypeptides that are produced by all Kingdoms of life to contribute to their species' own survival. Pore assembly is a sophisticated multi-step process that includes receptor/membrane recognition and oligomerization events, and is ensued by large-scale structural rearrangements, which facilitate maturation of a prepore into a functional membrane spanning pore. A full understanding of pore formation, assembly, and maturation has traditionally been hindered by a lack of structural data; particularly for assemblies representing differing conformations of functional pores. However, recent advancements in cryo-electron microscopy (cryo-EM) techniques have provided the opportunity to delineate the structures of such flexible complexes, and in different states, to near-atomic resolution. In this review, we place a particular emphasis on the use of cryo-EM to uncover the mechanistic details including architecture, activation, and maturation for some of the prominent members of this family.
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Affiliation(s)
- Harry Scott
- Department of PharmacologyCase Western Reserve UniversityClevelandOhio44106
| | - Wei Huang
- Department of PharmacologyCase Western Reserve UniversityClevelandOhio44106
| | - James G. Bann
- Department of ChemistryWichita State UniversityWichitaKansas67260
| | - Derek J. Taylor
- Department of PharmacologyCase Western Reserve UniversityClevelandOhio44106
- Department of BiochemistryCase Western Reserve UniversityClevelandOhio44106
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4
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The first transmembrane region of complement component-9 acts as a brake on its self-assembly. Nat Commun 2018; 9:3266. [PMID: 30111885 PMCID: PMC6093860 DOI: 10.1038/s41467-018-05717-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 07/09/2018] [Indexed: 11/09/2022] Open
Abstract
Complement component 9 (C9) functions as the pore-forming component of the Membrane Attack Complex (MAC). During MAC assembly, multiple copies of C9 are sequentially recruited to membrane associated C5b8 to form a pore. Here we determined the 2.2 Å crystal structure of monomeric murine C9 and the 3.9 Å resolution cryo EM structure of C9 in a polymeric assembly. Comparison with other MAC proteins reveals that the first transmembrane region (TMH1) in monomeric C9 is uniquely positioned and functions to inhibit its self-assembly in the absence of C5b8. We further show that following C9 recruitment to C5b8, a conformational change in TMH1 permits unidirectional and sequential binding of additional C9 monomers to the growing MAC. This mechanism of pore formation contrasts with related proteins, such as perforin and the cholesterol dependent cytolysins, where it is believed that pre-pore assembly occurs prior to the simultaneous release of the transmembrane regions.
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Majewski DD, Worrall LJ, Strynadka NCJ. Secretins revealed: structural insights into the giant gated outer membrane portals of bacteria. Curr Opin Struct Biol 2018; 51:61-72. [DOI: 10.1016/j.sbi.2018.02.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/28/2018] [Indexed: 01/19/2023]
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6
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Spicer BA, Conroy PJ, Law RH, Voskoboinik I, Whisstock JC. Perforin—A key (shaped) weapon in the immunological arsenal. Semin Cell Dev Biol 2017; 72:117-123. [DOI: 10.1016/j.semcdb.2017.07.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/05/2017] [Accepted: 07/21/2017] [Indexed: 12/31/2022]
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Near-atomic resolution cryoelectron microscopy structure of the 30-fold homooligomeric SpoIIIAG channel essential to spore formation in Bacillus subtilis. Proc Natl Acad Sci U S A 2017; 114:E7073-E7081. [PMID: 28784753 DOI: 10.1073/pnas.1704310114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Bacterial sporulation allows starving cells to differentiate into metabolically dormant spores that can survive extreme conditions. Following asymmetric division, the mother cell engulfs the forespore, surrounding it with two bilayer membranes. During the engulfment process, an essential channel, the so-called feeding tube apparatus, is thought to cross both membranes to create a direct conduit between the mother cell and the forespore. At least nine proteins are required to create this channel, including SpoIIQ and SpoIIIAA-AH. Here, we present the near-atomic resolution structure of one of these proteins, SpoIIIAG, determined by single-particle cryo-EM. A 3D reconstruction revealed that SpoIIIAG assembles into a large and stable 30-fold symmetric complex with a unique mushroom-like architecture. The complex is collectively composed of three distinctive circular structures: a 60-stranded vertical β-barrel that forms a large inner channel encircled by two concentric rings, one β-mediated and the other formed by repeats of a ring-building motif (RBM) common to the architecture of various dual membrane secretion systems of distinct function. Our near-atomic resolution structure clearly shows that SpoIIIAG exhibits a unique and dramatic adaptation of the RBM fold with a unique β-triangle insertion that assembles into the prominent channel, the dimensions of which suggest the potential passage of large macromolecules between the mother cell and forespore during the feeding process. Indeed, mutation of residues located at key interfaces between monomers of this RBM resulted in severe defects both in vivo and in vitro, providing additional support for this unprecedented structure.
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8
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Bayly-Jones C, Bubeck D, Dunstone MA. The mystery behind membrane insertion: a review of the complement membrane attack complex. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160221. [PMID: 28630159 PMCID: PMC5483522 DOI: 10.1098/rstb.2016.0221] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2016] [Indexed: 12/14/2022] Open
Abstract
The membrane attack complex (MAC) is an important innate immune effector of the complement terminal pathway that forms cytotoxic pores on the surface of microbes. Despite many years of research, MAC structure and mechanism of action have remained elusive, relying heavily on modelling and inference from biochemical experiments. Recent advances in structural biology, specifically cryo-electron microscopy, have provided new insights into the molecular mechanism of MAC assembly. Its unique 'split-washer' shape, coupled with an irregular giant β-barrel architecture, enable an atypical mechanism of hole punching and represent a novel system for which to study pore formation. This review will introduce the complement terminal pathway that leads to formation of the MAC. Moreover, it will discuss how structures of the pore and component proteins underpin a mechanism for MAC function, modulation and inhibition.This article is part of the themed issue 'Membrane pores: from structure and assembly, to medicine and technology'.
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Affiliation(s)
- Charles Bayly-Jones
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
| | - Doryen Bubeck
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW2 7AZ, UK
| | - Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
- ARC Centre of Excellence in Advanced Molecular Imaging, Biomedicine Discovery Institute, Monash University, Clayton Campus, Melbourne, Victoria 3800, Australia
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9
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Dudkina NV, Spicer BA, Reboul CF, Conroy PJ, Lukoyanova N, Elmlund H, Law RHP, Ekkel SM, Kondos SC, Goode RJA, Ramm G, Whisstock JC, Saibil HR, Dunstone MA. Structure of the poly-C9 component of the complement membrane attack complex. Nat Commun 2016; 7:10588. [PMID: 26841934 PMCID: PMC4742998 DOI: 10.1038/ncomms10588] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 12/31/2015] [Indexed: 12/11/2022] Open
Abstract
The membrane attack complex (MAC)/perforin-like protein complement component 9 (C9) is the major component of the MAC, a multi-protein complex that forms pores in the membrane of target pathogens. In contrast to homologous proteins such as perforin and the cholesterol-dependent cytolysins (CDCs), all of which require the membrane for oligomerisation, C9 assembles directly onto the nascent MAC from solution. However, the molecular mechanism of MAC assembly remains to be understood. Here we present the 8 Å cryo-EM structure of a soluble form of the poly-C9 component of the MAC. These data reveal a 22-fold symmetrical arrangement of C9 molecules that yield an 88-strand pore-forming β-barrel. The N-terminal thrombospondin-1 (TSP1) domain forms an unexpectedly extensive part of the oligomerisation interface, thus likely facilitating solution-based assembly. These TSP1 interactions may also explain how additional C9 subunits can be recruited to the growing MAC subsequent to membrane insertion.
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Affiliation(s)
- Natalya V. Dudkina
- Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, London WC1E 7HX, UK
| | - Bradley A. Spicer
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Cyril F. Reboul
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Paul J. Conroy
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Natalya Lukoyanova
- Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, London WC1E 7HX, UK
| | - Hans Elmlund
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Ruby H. P. Law
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Susan M. Ekkel
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Stephanie C. Kondos
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Robert J. A. Goode
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Georg Ramm
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - James C. Whisstock
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
| | - Helen R. Saibil
- Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, London WC1E 7HX, UK
| | - Michelle A. Dunstone
- ARC Centre of Excellence in Advanced Molecular Imaging, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, Victoria 3800, Australia
- Department of Microbiology, Biomedicine Discovery Institute, Clayton Campus, Monash University, Melbourne, 3800 Victoria, Australia
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Lukoyanova N, Hoogenboom BW, Saibil HR. The membrane attack complex, perforin and cholesterol-dependent cytolysin superfamily of pore-forming proteins. J Cell Sci 2016; 129:2125-33. [DOI: 10.1242/jcs.182741] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
ABSTRACT
The membrane attack complex and perforin proteins (MACPFs) and bacterial cholesterol-dependent cytolysins (CDCs) are two branches of a large and diverse superfamily of pore-forming proteins that function in immunity and pathogenesis. During pore formation, soluble monomers assemble into large transmembrane pores through conformational transitions that involve extrusion and refolding of two α-helical regions into transmembrane β-hairpins. These transitions entail a dramatic refolding of the protein structure, and the resulting assemblies create large holes in cellular membranes, but they do not use any external source of energy. Structures of the membrane-bound assemblies are required to mechanistically understand and modulate these processes. In this Commentary, we discuss recent advances in the understanding of assembly mechanisms and molecular details of the conformational changes that occur during MACPF and CDC pore formation.
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Affiliation(s)
- Natalya Lukoyanova
- Department of Crystallography/Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London WC1E 7HX, UK
| | - Bart W. Hoogenboom
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
- Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
| | - Helen R. Saibil
- Department of Crystallography/Biological Sciences, Institute of Structural and Molecular Biology, Birkbeck College, London WC1E 7HX, UK
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11
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Stonefish toxin defines an ancient branch of the perforin-like superfamily. Proc Natl Acad Sci U S A 2015; 112:15360-5. [PMID: 26627714 DOI: 10.1073/pnas.1507622112] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The lethal factor in stonefish venom is stonustoxin (SNTX), a heterodimeric cytolytic protein that induces cardiovascular collapse in humans and native predators. Here, using X-ray crystallography, we make the unexpected finding that SNTX is a pore-forming member of an ancient branch of the Membrane Attack Complex-Perforin/Cholesterol-Dependent Cytolysin (MACPF/CDC) superfamily. SNTX comprises two homologous subunits (α and β), each of which comprises an N-terminal pore-forming MACPF/CDC domain, a central focal adhesion-targeting domain, a thioredoxin domain, and a C-terminal tripartite motif family-like PRY SPla and the RYanodine Receptor immune recognition domain. Crucially, the structure reveals that the two MACPF domains are in complex with one another and arranged into a stable early prepore-like assembly. These data provide long sought after near-atomic resolution insights into how MACPF/CDC proteins assemble into prepores on the surface of membranes. Furthermore, our analyses reveal that SNTX-like MACPF/CDCs are distributed throughout eukaryotic life and play a broader, possibly immune-related function outside venom.
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12
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Reboul CF, Whisstock JC, Dunstone MA. Giant MACPF/CDC pore forming toxins: A class of their own. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1858:475-86. [PMID: 26607011 DOI: 10.1016/j.bbamem.2015.11.017] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 11/16/2015] [Accepted: 11/17/2015] [Indexed: 01/08/2023]
Abstract
Pore Forming Toxins (PFTs) represent a key mechanism for permitting the passage of proteins and small molecules across the lipid membrane. These proteins are typically produced as soluble monomers that self-assemble into ring-like oligomeric structures on the membrane surface. Following such assembly PFTs undergo a remarkable conformational change to insert into the lipid membrane. While many different protein families have independently evolved such ability, members of the Membrane Attack Complex PerForin/Cholesterol Dependent Cytolysin (MACPF/CDC) superfamily form distinctive giant β-barrel pores comprised of up to 50 monomers and up to 300Å in diameter. In this review we focus on recent advances in understanding the structure of these giant MACPF/CDC pores as well as the underlying molecular mechanisms leading to their formation. Commonalities and evolved variations of the pore forming mechanism across the superfamily are discussed. This article is part of a Special Issue entitled: Pore-Forming Toxins edited by Mauro Dalla Serra and Franco Gambale.
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Affiliation(s)
- Cyril F Reboul
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Melbourne, Australia
| | - James C Whisstock
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Melbourne, Australia
| | - Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Melbourne, Australia; Department of Microbiology, Monash University, Melbourne, Australia
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14
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Conformational changes during pore formation by the perforin-related protein pleurotolysin. PLoS Biol 2015; 13:e1002049. [PMID: 25654333 PMCID: PMC4318580 DOI: 10.1371/journal.pbio.1002049] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 12/10/2014] [Indexed: 12/17/2022] Open
Abstract
Membrane attack complex/perforin-like (MACPF) proteins comprise the largest superfamily of pore-forming proteins, playing crucial roles in immunity and pathogenesis. Soluble monomers assemble into large transmembrane pores via conformational transitions that remain to be structurally and mechanistically characterised. Here we present an 11 Å resolution cryo-electron microscopy (cryo-EM) structure of the two-part, fungal toxin Pleurotolysin (Ply), together with crystal structures of both components (the lipid binding PlyA protein and the pore-forming MACPF component PlyB). These data reveal a 13-fold pore 80 Å in diameter and 100 Å in height, with each subunit comprised of a PlyB molecule atop a membrane bound dimer of PlyA. The resolution of the EM map, together with biophysical and computational experiments, allowed confident assignment of subdomains in a MACPF pore assembly. The major conformational changes in PlyB are a ∼70° opening of the bent and distorted central β-sheet of the MACPF domain, accompanied by extrusion and refolding of two α-helical regions into transmembrane β-hairpins (TMH1 and TMH2). We determined the structures of three different disulphide bond-trapped prepore intermediates. Analysis of these data by molecular modelling and flexible fitting allows us to generate a potential trajectory of β-sheet unbending. The results suggest that MACPF conformational change is triggered through disruption of the interface between a conserved helix-turn-helix motif and the top of TMH2. Following their release we propose that the transmembrane regions assemble into β-hairpins via top down zippering of backbone hydrogen bonds to form the membrane-inserted β-barrel. The intermediate structures of the MACPF domain during refolding into the β-barrel pore establish a structural paradigm for the transition from soluble monomer to pore, which may be conserved across the whole superfamily. The TMH2 region is critical for the release of both TMH clusters, suggesting why this region is targeted by endogenous inhibitors of MACPF function. Animals, plants, fungi, and bacteria all use pore-forming proteins of the membrane attack complex-perforin (MACPF) family as lethal, cell-killing weapons. These proteins are able to insert into the plasma membranes of target cells, creating large pores that short circuit the natural separation between the intracellular and extracellular milieu, with catastrophic results. However, the pore-forming proteins must undergo a substantial transformation from soluble precursors to a large barrel-shaped transmembrane complex as they punch their way into cells. Using a combination of X-ray crystallography and cryo electron microscopy, we have visualized, for the first time, the mechanism of action of one of these pore-forming proteins—pleurotolysin, a MACPF protein from the edible oyster mushroom. This enabled us to propose a model of the pleurotolysin pore by fitting the crystallographic structures of the pore proteins into a three-dimensional map of the pore obtained by cryo electron microscopy. We then designed a set of double mutants that allowed us to chemically trap intermediate states along the trajectory of the pore formation process, and to determine their structures too. By combining these data we proposed a detailed molecular mechanism for pore formation. The pleurotolysin first assembles into rings of 13 subunits, each of which then opens up by about 70° during pore formation. This process is accompanied by refolding and extrusion of two compact regions from each subunit into long hairpins that then zipper together to form an 80-Å wide barrel-shaped channel through the membrane. A combination of structural methods reveals the complex process by which the perforin-like fungal toxin Pleurotolysin rearranges its structure to form a pore that punches a hole in target cell membranes.
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15
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Tweten RK, Hotze EM, Wade KR. The Unique Molecular Choreography of Giant Pore Formation by the Cholesterol-Dependent Cytolysins of Gram-Positive Bacteria. Annu Rev Microbiol 2015; 69:323-40. [PMID: 26488276 PMCID: PMC7875328 DOI: 10.1146/annurev-micro-091014-104233] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The mechanism by which the cholesterol-dependent cytolysins (CDCs) assemble their giant β-barrel pore in cholesterol-rich membranes has been the subject of intense study in the past two decades. A combination of structural, biophysical, and biochemical analyses has revealed deep insights into the series of complex and highly choreographed secondary and tertiary structural transitions that the CDCs undergo to assemble their β-barrel pore in eukaryotic membranes. Our knowledge of the molecular details of these dramatic structural changes in CDCs has transformed our understanding of how giant pore complexes are assembled and has been critical to our understanding of the mechanisms of other important classes of pore-forming toxins and proteins across the kingdoms of life. Finally, there are tantalizing hints that the CDC pore-forming mechanism is more sophisticated than previously imagined and that some CDCs are employed in pore-independent processes.
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Affiliation(s)
- Rodney K Tweten
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
| | - Eileen M Hotze
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
| | - Kristin R Wade
- Department of Microbiology and Immunology, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104;
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Leung C, Dudkina NV, Lukoyanova N, Hodel AW, Farabella I, Pandurangan AP, Jahan N, Pires Damaso M, Osmanović D, Reboul CF, Dunstone MA, Andrew PW, Lonnen R, Topf M, Saibil HR, Hoogenboom BW. Stepwise visualization of membrane pore formation by suilysin, a bacterial cholesterol-dependent cytolysin. eLife 2014; 3:e04247. [PMID: 25457051 PMCID: PMC4381977 DOI: 10.7554/elife.04247] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 11/24/2014] [Indexed: 12/23/2022] Open
Abstract
Membrane attack complex/perforin/cholesterol-dependent cytolysin (MACPF/CDC) proteins constitute a major superfamily of pore-forming proteins that act as bacterial virulence factors and effectors in immune defence. Upon binding to the membrane, they convert from the soluble monomeric form to oligomeric, membrane-inserted pores. Using real-time atomic force microscopy (AFM), electron microscopy (EM), and atomic structure fitting, we have mapped the structure and assembly pathways of a bacterial CDC in unprecedented detail and accuracy, focussing on suilysin from Streptococcus suis. We show that suilysin assembly is a noncooperative process that is terminated before the protein inserts into the membrane. The resulting ring-shaped pores and kinetically trapped arc-shaped assemblies are all seen to perforate the membrane, as also visible by the ejection of its lipids. Membrane insertion requires a concerted conformational change of the monomeric subunits, with a marked expansion in pore diameter due to large changes in subunit structure and packing.
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Affiliation(s)
- Carl Leung
- London Centre for Nanotechnology, University College London, London, United Kingdom
| | - Natalya V Dudkina
- Department of Crystallography, Birkbeck College, London, United Kingdom
| | | | - Adrian W Hodel
- London Centre for Nanotechnology, University College London, London, United Kingdom
| | - Irene Farabella
- Department of Crystallography, Birkbeck College, London, United Kingdom
| | | | - Nasrin Jahan
- Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Mafalda Pires Damaso
- Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Dino Osmanović
- London Centre for Nanotechnology, University College London, London, United Kingdom
| | - Cyril F Reboul
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Australia
| | - Peter W Andrew
- Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Rana Lonnen
- Department of Infection, Immunity, and Inflammation, University of Leicester, Leicester, United Kingdom
| | - Maya Topf
- Department of Crystallography, Birkbeck College, London, United Kingdom
| | - Helen R Saibil
- Department of Crystallography, Birkbeck College, London, United Kingdom
| | - Bart W Hoogenboom
- London Centre for Nanotechnology, University College London, London, United Kingdom
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A new model for pore formation by cholesterol-dependent cytolysins. PLoS Comput Biol 2014; 10:e1003791. [PMID: 25144725 PMCID: PMC4140638 DOI: 10.1371/journal.pcbi.1003791] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 07/01/2014] [Indexed: 11/19/2022] Open
Abstract
Cholesterol Dependent Cytolysins (CDCs) are important bacterial virulence factors that form large (200–300 Å) membrane embedded pores in target cells. Currently, insights from X-ray crystallography, biophysical and single particle cryo-Electron Microscopy (cryo-EM) experiments suggest that soluble monomers first interact with the membrane surface via a C-terminal Immunoglobulin-like domain (Ig; Domain 4). Membrane bound oligomers then assemble into a prepore oligomeric form, following which the prepore assembly collapses towards the membrane surface, with concomitant release and insertion of the membrane spanning subunits. During this rearrangement it is proposed that Domain 2, a region comprising three β-strands that links the pore forming region (Domains 1 and 3) and the Ig domain, must undergo a significant yet currently undetermined, conformational change. Here we address this problem through a systematic molecular modeling and structural bioinformatics approach. Our work shows that simple rigid body rotations may account for the observed collapse of the prepore towards the membrane surface. Support for this idea comes from analysis of published cryo-EM maps of the pneumolysin pore, available crystal structures and molecular dynamics simulations. The latter data in particular reveal that Domains 1, 2 and 4 are able to undergo significant rotational movements with respect to each other. Together, our data provide new and testable insights into the mechanism of pore formation by CDCs. Pore formation is central to the ability of cholesterol dependent cytolysins (CDCs) to act as important bacterial virulence factors. Secreted by numerous pathogens the toxins assemble into a circular ring and then perforate the target membrane to form the largest self-assembling proteinaceous pores known. In this paper we investigated computationally the conformational properties of the CDC molecule and deduced a new structural model of pore formation and membrane insertion that reconciles all experimental data. The mechanism of membrane perforation by CDCs put forward here reveals concerted and unsuspected domains motion of large amplitude, which conflicts with the currently proposed model. The work presented here procures a plausible structural mechanism of CDC oligomeric transition and furthers our understanding of pore formation by these important toxins.
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Yan R, Lin J, Chen Z, Wang X, Huang L, Cai W, Zhang Z. Prediction of outer membrane proteins by combining the position- and composition-based features of sequence profiles. MOLECULAR BIOSYSTEMS 2014; 10:1004-13. [DOI: 10.1039/c3mb70435a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The present study resolves the molecular mechanism behind the key first steps in the action of an essential immune protein, cytotoxic lymphocyte perforin, binding to the plasma membrane of a target cell and initiation of pore formation.
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Sato TK, Tweten RK, Johnson AE. Disulfide-bond scanning reveals assembly state and β-strand tilt angle of the PFO β-barrel. Nat Chem Biol 2013; 9:383-9. [PMID: 23563525 PMCID: PMC3661704 DOI: 10.1038/nchembio.1228] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 02/28/2013] [Indexed: 12/29/2022]
Abstract
Perfringolysin O (PFO), a bacterial cholesterol-dependent cytolysin, binds a mammalian cell membrane, oligomerizes into a circular prepore complex (PPC) and forms a 250-Å transmembrane β-barrel pore in the cell membrane. Each PFO monomer has two sets of three short α-helices that unfold and ultimately refold into two transmembrane β-hairpin (TMH) components of the membrane-embedded β-barrel. Interstrand disulfide-bond scanning revealed that β-strands in a fully assembled PFO β-barrel were strictly aligned and tilted at 20° to the membrane perpendicular. In contrast, in a low temperature-trapped PPC intermediate, the TMHs were unfolded and had sufficient freedom of motion to interact transiently with each other, yet the TMHs were not aligned or stably hydrogen bonded. The PFO PPC-to-pore transition therefore converts TMHs in a dynamic folding intermediate far above the membrane into TMHs that are hydrogen bonded to those of adjacent subunits in the bilayer-embedded β-barrel.
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Affiliation(s)
- Takehiro K. Sato
- Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, College Station, TX 77843-1114
| | - Rodney K. Tweten
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73119
| | - Arthur E. Johnson
- Department of Molecular and Cellular Medicine, Texas A&M University System Health Science Center, College Station, TX 77843-1114
- Department of Chemistry, Texas A&M University, College Station, TX 77843
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843
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Dunstone MA, Tweten RK. Packing a punch: the mechanism of pore formation by cholesterol dependent cytolysins and membrane attack complex/perforin-like proteins. Curr Opin Struct Biol 2012; 22:342-9. [PMID: 22658510 DOI: 10.1016/j.sbi.2012.04.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 11/29/2022]
Abstract
The bacterial cholesterol dependent cytolysins (CDCs) and membrane attack complex/perforin-like proteins (MACPF) represent two major branches of a large, exceptionally diverged superfamily. Most characterized CDC/MACPF proteins form large pores that function in immunity, venoms, and pathogenesis. Extensive structural, biochemical and biophysical studies have started to address some of the questions surrounding how the soluble, monomeric form of these remarkable molecules recognize diverse targets and assemble into oligomeric membrane embedded pores. This review explores mechanistic similarities and differences in how CDCs and MACPF proteins form pores.
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Affiliation(s)
- Michelle A Dunstone
- Department of Biochemistry and Molecular Biology, Monash University, Wellington Road, Clayton, VIC 3800, Australia
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