1
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Macé K, Waksman G. Cryo-EM structure of a conjugative type IV secretion system suggests a molecular switch regulating pilus biogenesis. EMBO J 2024; 43:3287-3306. [PMID: 38886579 PMCID: PMC11294453 DOI: 10.1038/s44318-024-00135-z] [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: 02/07/2024] [Revised: 05/17/2024] [Accepted: 05/21/2024] [Indexed: 06/20/2024] Open
Abstract
Conjugative type IV secretion systems (T4SS) mediate bacterial conjugation, a process that enables the unidirectional exchange of genetic materials between a donor and a recipient bacterial cell. Bacterial conjugation is the primary means by which antibiotic resistance genes spread among bacterial populations (Barlow 2009; Virolle et al, 2020). Conjugative T4SSs form pili: long extracellular filaments that connect with recipient cells. Previously, we solved the cryo-electron microscopy (cryo-EM) structure of a conjugative T4SS. In this article, based on additional data, we present a more complete T4SS cryo-EM structure than that published earlier. Novel structural features include details of the mismatch symmetry within the OMCC, the presence of a fourth VirB8 subunit in the asymmetric unit of both the arches and the inner membrane complex (IMC), and a hydrophobic VirB5 tip in the distal end of the stalk. Additionally, we provide previously undescribed structural insights into the protein VirB10 and identify a novel regulation mechanism of T4SS-mediated pilus biogenesis by this protein, that we believe is a key checkpoint for this process.
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Affiliation(s)
- Kévin Macé
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK.
- Univ. Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) - UMR6290, 35000, Rennes, France.
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK.
- Institute of Structural and Molecular Biology, Division of Biosciences, Gower Street, University College London, London, WC1E 6BT, UK.
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2
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Vadakkepat AK, Xue S, Redzej A, Smith TK, Ho BT, Waksman G. Cryo-EM structure of the R388 plasmid conjugative pilus reveals a helical polymer characterized by an unusual pilin/phospholipid binary complex. Structure 2024:S0969-2126(24)00227-2. [PMID: 39002540 DOI: 10.1016/j.str.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 05/14/2024] [Accepted: 06/18/2024] [Indexed: 07/15/2024]
Abstract
Bacterial conjugation is a process by which DNA is transferred unidirectionally from a donor cell to a recipient cell. It is the main means by which antibiotic resistance genes spread among bacterial populations. It is crucially dependent upon the elaboration of an extracellular appendage, termed "pilus," by a large double-membrane-spanning secretion system termed conjugative "type IV secretion system." Here we present the structure of the conjugative pilus encoded by the R388 plasmid. We demonstrate that, as opposed to all conjugative pili produced so far for cryoelectron microscopy (cryo-EM) structure determination, the conjugative pilus encoded by the R388 plasmid is greatly stimulated by the presence of recipient cells. Comparison of its cryo-EM structure with existing conjugative pilus structures highlights a number of important differences between the R388 pilus structure and that of its homologs, the most prominent being the highly distinctive conformation of its bound lipid.
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Affiliation(s)
- Abhinav K Vadakkepat
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK.
| | - Songlin Xue
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Adam Redzej
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Terry K Smith
- BSRC, School of Biology, University of St Andrews, St Andrews KY16 9AJ, UK
| | - Brian T Ho
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK; Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London WC1E 7HX, UK; Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, UK.
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3
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Angulo-Cánovas E, Bartual A, López-Igual R, Luque I, Radzinski NP, Shilova I, Anjur-Dietrich M, García-Jurado G, Úbeda B, González-Reyes JA, Díez J, Chisholm SW, García-Fernández JM, del Carmen Muñoz-Marín M. Direct interaction between marine cyanobacteria mediated by nanotubes. SCIENCE ADVANCES 2024; 10:eadj1539. [PMID: 38781331 PMCID: PMC11114229 DOI: 10.1126/sciadv.adj1539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 04/16/2024] [Indexed: 05/25/2024]
Abstract
Microbial associations and interactions drive and regulate nutrient fluxes in the ocean. However, physical contact between cells of marine cyanobacteria has not been studied thus far. Here, we show a mechanism of direct interaction between the marine cyanobacteria Prochlorococcus and Synechococcus, the intercellular membrane nanotubes. We present evidence of inter- and intra-genus exchange of cytoplasmic material between neighboring and distant cells of cyanobacteria mediated by nanotubes. We visualized and measured these structures in xenic and axenic cultures and in natural samples. We show that nanotubes are produced between living cells, suggesting that this is a relevant system of exchange material in vivo. The discovery of nanotubes acting as exchange bridges in the most abundant photosynthetic organisms in the ocean may have important implications for their interactions with other organisms and their population dynamics.
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Affiliation(s)
- Elisa Angulo-Cánovas
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba 14014, Spain
| | - Ana Bartual
- Instituto Universitario de Investigaciones Marinas (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
| | - Rocío López-Igual
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Sevilla, Spain
| | - Ignacio Luque
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Sevilla, Spain
| | - Nikolai P. Radzinski
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Maya Anjur-Dietrich
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Gema García-Jurado
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
| | - Bárbara Úbeda
- Instituto Universitario de Investigaciones Marinas (INMAR), Campus de Excelencia Internacional del Mar (CEI·MAR), Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain
| | - José Antonio González-Reyes
- Departamento de Biología Celular, Fisiología e Inmunología, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba 14014, Spain
| | - Jesús Díez
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba 14014, Spain
| | - Sallie W. Chisholm
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - José Manuel García-Fernández
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba 14014, Spain
| | - María del Carmen Muñoz-Marín
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario, Universidad de Córdoba, Córdoba 14014, Spain
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4
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Thongchol J, Yu Z, Harb L, Lin Y, Koch M, Theodore M, Narsaria U, Shaevitz J, Gitai Z, Wu Y, Zhang J, Zeng L. Removal of Pseudomonas type IV pili by a small RNA virus. Science 2024; 384:eadl0635. [PMID: 38574145 PMCID: PMC11126211 DOI: 10.1126/science.adl0635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/29/2024] [Indexed: 04/06/2024]
Abstract
The retractile type IV pilus (T4P) is important for virulence of the opportunistic human pathogen Pseudomonas aeruginosa. The single-stranded RNA (ssRNA) phage PP7 binds to T4P and is brought to the cell surface through pilus retraction. Using fluorescence microscopy, we discovered that PP7 detaches T4P, which impairs cell motility and restricts the pathogen's virulence. Using cryo-electron microscopy, mutagenesis, optical trapping, and Langevin dynamics simulation, we resolved the structure of PP7, T4P, and the PP7/T4P complex and showed that T4P detachment is driven by the affinity between the phage maturation protein and its bound pilin, plus the pilus retraction force and speed, and pilus bending. Pilus detachment may be widespread among other ssRNA phages and their retractile pilus systems and offers new prospects for antibacterial prophylaxis and therapeutics.
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Affiliation(s)
- Jirapat Thongchol
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Zihao Yu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Laith Harb
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Yiruo Lin
- Department of Computer Science and Engineering, Texas A&M University, College Station, TX 77843, USA
| | - Matthias Koch
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Matthew Theodore
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Utkarsh Narsaria
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Joshua Shaevitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Joseph Henry Laboratories of Physics, Princeton University, Princeton, NJ 08544, USA
| | - Zemer Gitai
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Yinghao Wu
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, NY 10461, USA
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
- Center for Phage Technology, Texas A&M University, College Station, TX 77843, USA
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5
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Costa TRD, Patkowski JB, Macé K, Christie PJ, Waksman G. Structural and functional diversity of type IV secretion systems. Nat Rev Microbiol 2024; 22:170-185. [PMID: 37814112 PMCID: PMC11290344 DOI: 10.1038/s41579-023-00974-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2023] [Indexed: 10/11/2023]
Abstract
Considerable progress has been made in recent years in the structural and molecular biology of type IV secretion systems in Gram-negative bacteria. The latest advances have substantially improved our understanding of the mechanisms underlying the recruitment and delivery of DNA and protein substrates to the extracellular environment or target cells. In this Review, we aim to summarize these exciting structural and molecular biology findings and to discuss their functional implications for substrate recognition, recruitment and translocation, as well as the biogenesis of extracellular pili. We also describe adaptations necessary for deploying a breadth of processes, such as bacterial survival, host-pathogen interactions and biotic and abiotic adhesion. We highlight the functional and structural diversity that allows this extremely versatile secretion superfamily to function under different environmental conditions and in different bacterial species. Additionally, we emphasize the importance of further understanding the mechanism of type IV secretion, which will support us in combating antimicrobial resistance and treating type IV secretion system-related infections.
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Affiliation(s)
- Tiago R D Costa
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College, London, UK.
| | - Jonasz B Patkowski
- Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College, London, UK
| | - Kévin Macé
- Institute of Structural and Molecular Biology, Birkbeck and UCL, London, UK
- Institut de Génétique et Développement de Rennes (IGDR), Université de Rennes and CNRS, Rennes, France
| | - Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, TX, USA.
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, Birkbeck and UCL, London, UK.
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6
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Kishida K, Li YG, Ogawa-Kishida N, Khara P, Al Mamun AAM, Bosserman RE, Christie PJ. Chimeric systems composed of swapped Tra subunits between distantly-related F plasmids reveal striking plasticity among type IV secretion machines. PLoS Genet 2024; 20:e1011088. [PMID: 38437248 PMCID: PMC10939261 DOI: 10.1371/journal.pgen.1011088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 03/14/2024] [Accepted: 02/20/2024] [Indexed: 03/06/2024] Open
Abstract
Bacterial type IV secretion systems (T4SSs) are a versatile family of macromolecular translocators, collectively able to recruit diverse DNA and protein substrates and deliver them to a wide range of cell types. Presently, there is little understanding of how T4SSs recognize substrate repertoires and form productive contacts with specific target cells. Although T4SSs are composed of a number of conserved subunits and adopt certain conserved structural features, they also display considerable compositional and structural diversity. Here, we explored the structural bases underlying the functional versatility of T4SSs through systematic deletion and subunit swapping between two conjugation systems encoded by the distantly-related IncF plasmids, pED208 and F. We identified several regions of intrinsic flexibility among the encoded T4SSs, as evidenced by partial or complete functionality of chimeric machines. Swapping of VirD4-like TraD type IV coupling proteins (T4CPs) yielded functional chimeras, indicative of relaxed specificity at the substrate-TraD and TraD-T4SS interfaces. Through mutational analyses, we further delineated domains of the TraD T4CPs contributing to recruitment of cognate vs heterologous DNA substrates. Remarkably, swaps of components comprising the outer membrane core complexes, a few F-specific subunits, or the TraA pilins supported DNA transfer in the absence of detectable pilus production. Among sequenced enterobacterial species in the NCBI database, we identified many strains that harbor two or more F-like plasmids and many F plasmids lacking one or more T4SS components required for self-transfer. We confirmed that host cells carrying co-resident, non-selftransmissible variants of pED208 and F elaborate chimeric T4SSs, as evidenced by transmission of both plasmids. We propose that T4SS plasticity enables the facile assembly of functional chimeras, and this intrinsic flexibility at the structural level can account for functional diversification of this superfamily over evolutionary time and, on a more immediate time-scale, to proliferation of transfer-defective MGEs in nature.
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Affiliation(s)
- Kouhei Kishida
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
| | - Yang Grace Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
| | - Natsumi Ogawa-Kishida
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
| | - Pratick Khara
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
| | - Abu Amar M. Al Mamun
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
| | - Rachel E. Bosserman
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, Texas, United States of America
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7
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Beltrán L, Torsilieri H, Patkowski JB, Yang JE, Casanova J, Costa TRD, Wright ER, Egelman EH. The mating pilus of E. coli pED208 acts as a conduit for ssDNA during horizontal gene transfer. mBio 2024; 15:e0285723. [PMID: 38051116 PMCID: PMC10790687 DOI: 10.1128/mbio.02857-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Bacteria are constantly exchanging DNA, which constitutes horizontal gene transfer. While some of these occurs by a non-specific process called natural transformation, some occurs by a specific mating between a donor and a recipient cell. In specific conjugation, the mating pilus is extended from the donor cell to make contact with the recipient cell, but whether DNA is actually transferred through this pilus or by another mechanism involving the type IV secretion system complex without the pilus has been an open question. Using Escherichia coli, we show that DNA can be transferred through this pilus between a donor and a recipient cell that has not established a tight mating junction, providing a new picture for the role of this pilus.
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Affiliation(s)
- Leticia Beltrán
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, USA
| | - Holly Torsilieri
- Department of Molecular Cell Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Jonasz B. Patkowski
- Department of Life Sciences, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Jie E. Yang
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - James Casanova
- Department of Molecular Cell Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Tiago R. D. Costa
- Department of Life Sciences, Centre for Bacterial Resistance Biology, Imperial College London, London, United Kingdom
| | - Elizabeth R. Wright
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Edward H. Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, Virginia, USA
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8
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Thongchol J, Zhang J. Purification of Single-Stranded RNA Bacteriophages and Host Receptors for Structural Determination Using Cryo-Electron Microscopy. Methods Mol Biol 2024; 2793:185-204. [PMID: 38526732 DOI: 10.1007/978-1-0716-3798-2_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
Single-stranded RNA bacteriophages (ssRNA phages) are small viruses with a compact genome (~3-4 kb) that infect gram-negative bacteria via retractile pili. These phages have been applied in various fields since their discovery approximately 60 years ago. To understand their biology, it is crucial to analyze the structure of mature virions. Cryo-electron microscopy (cryo-EM) has been employed to determine the structures of two ssRNA phages, MS2 and Qβ. This chapter presents a method for purifying these two phages and their receptor, the F-pilus, to allow examination using cryo-EM.
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Affiliation(s)
- Jirapat Thongchol
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Junjie Zhang
- Center for Phage Technology, Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
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9
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Christie PJ. Illuminating type IV secretion-mediated DNA trafficking through long filaments. Proc Natl Acad Sci U S A 2023; 120:e2318508120. [PMID: 38019843 PMCID: PMC10722965 DOI: 10.1073/pnas.2318508120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023] Open
Affiliation(s)
- Peter J Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, Houston, TX 77030
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10
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Kishida K, Li YG, Ogawa-Kishida N, Khara P, Al Mamun AAM, Bosserman RE, Christie PJ. Chimeric systems composed of swapped Tra subunits between distantly-related F plasmids reveal striking plasticity among type IV secretion machines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570194. [PMID: 38106057 PMCID: PMC10723329 DOI: 10.1101/2023.12.05.570194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Bacterial type IV secretion systems (T4SSs) are a versatile family of macromolecular translocators, collectively able to recruit diverse DNA and protein substrates and deliver them to a wide range of cell types. Presently, there is little understanding of how T4SSs recognize substrate repertoires and form productive contacts with specific target cells. Although T4SSs are composed of a number of conserved subunits and adopt certain conserved structural features, they also display considerable compositional and structural diversity. Here, we explored the structural bases underlying the functional versatility of T4SSs through systematic deletion and subunit swapping between two conjugation systems encoded by the distantly-related IncF plasmids, pED208 and F. We identified several regions of intrinsic flexibility among the encoded T4SSs, as evidenced by partial or complete functionality of chimeric machines. Swapping of VirD4-like TraD type IV coupling proteins (T4CPs) yielded functional chimeras, indicative of relaxed specificity at the substrate - TraD and TraD - T4SS interfaces. Through mutational analyses, we further delineated domains of the TraD T4CPs contributing to recruitment of cognate vs heterologous DNA substrates. Remarkably, swaps of components comprising the outer membrane core complexes, a few F-specific subunits, or the TraA pilins supported DNA transfer in the absence of detectable pilus production. Among sequenced enterobacterial species in the NCBI database, we identified many strains that harbor two or more F-like plasmids and many F plasmids lacking one or more T4SS components required for self-transfer. We confirmed that host cells carrying co-resident, non-selftransmissible variants of pED208 and F elaborate chimeric T4SSs, as evidenced by transmission of both plasmids. We propose that T4SS plasticity enables the facile assembly of functional chimeras, and this intrinsic flexibility at the structural level can account for functional diversification of this superfamily over evolutionary time and, on a more immediate time-scale, to proliferation of transfer-defective MGEs in nature.
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Affiliation(s)
- Kouhei Kishida
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
| | - Yang Grace Li
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
| | - Natsumi Ogawa-Kishida
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
| | - Pratick Khara
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
| | - Abu Amar M Al Mamun
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
| | - Rachel E. Bosserman
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics, McGovern Medical School at UTHealth, 6431 Fannin St, Houston, Texas 77030, United States of America
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11
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Cabezón E, Valenzuela-Gómez F, Arechaga I. Primary architecture and energy requirements of Type III and Type IV secretion systems. Front Cell Infect Microbiol 2023; 13:1255852. [PMID: 38089815 PMCID: PMC10711112 DOI: 10.3389/fcimb.2023.1255852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 11/08/2023] [Indexed: 12/18/2023] Open
Abstract
Many pathogens use Type III and Type IV protein secretion systems to secrete virulence factors from the bacterial cytosol into host cells. These systems operate through a one-step mechanism. The secreted substrates (protein or nucleo-protein complexes in the case of Type IV conjugative systems) are guided to the base of the secretion channel, where they are directly delivered into the host cell in an ATP-dependent unfolded state. Despite the numerous disparities between these secretion systems, here we have focused on the structural and functional similarities between both systems. In particular, on the structural similarity shared by one of the main ATPases (EscN and VirD4 in Type III and Type IV secretion systems, respectively). Interestingly, these ATPases also exhibit a structural resemblance to F1-ATPases, which suggests a common mechanism for substrate secretion. The correlation between structure and function of essential components in both systems can provide significant insights into the molecular mechanisms involved. This approach is of great interest in the pursuit of identifying inhibitors that can effectively target these systems.
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Affiliation(s)
- Elena Cabezón
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria- CSIC, Santander, Spain
| | | | - Ignacio Arechaga
- Departamento de Biología Molecular and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria- CSIC, Santander, Spain
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12
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Goldlust K, Ducret A, Halte M, Dedieu-Berne A, Erhardt M, Lesterlin C. The F pilus serves as a conduit for the DNA during conjugation between physically distant bacteria. Proc Natl Acad Sci U S A 2023; 120:e2310842120. [PMID: 37963249 PMCID: PMC10666033 DOI: 10.1073/pnas.2310842120] [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: 06/28/2023] [Accepted: 09/27/2023] [Indexed: 11/16/2023] Open
Abstract
Horizontal transfer of F-like plasmids by bacterial conjugation is responsible for disseminating antibiotic resistance and virulence determinants among pathogenic Enterobacteriaceae species, a growing health concern worldwide. Central to this process is the conjugative F pilus, a long extracellular filamentous polymer that extends from the surface of plasmid donor cells, allowing it to probe the environment and make contact with the recipient cell. It is well established that the F pilus can retract to bring mating pair cells in tight contact before DNA transfer. However, whether DNA transfer can occur through the extended pilus has been a subject of active debate. In this study, we use live-cell microscopy to show that while most transfer events occur between cells in direct contact, the F pilus can indeed serve as a conduit for the DNA during transfer between physically distant cells. Our findings enable us to propose a unique model for conjugation that revises our understanding of the DNA transfer mechanism and the dissemination of drug resistance and virulence genes within complex bacterial communities.
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Affiliation(s)
- Kelly Goldlust
- Molecular Microbiology and Structural Biochemistry, Université Lyon 1, CNRS, Inserm, UMR5086, Lyon69007, France
| | - Adrien Ducret
- Molecular Microbiology and Structural Biochemistry, Université Lyon 1, CNRS, Inserm, UMR5086, Lyon69007, France
| | - Manuel Halte
- Institute for Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin10115, Germany
| | - Annick Dedieu-Berne
- Molecular Microbiology and Structural Biochemistry, Université Lyon 1, CNRS, Inserm, UMR5086, Lyon69007, France
| | - Marc Erhardt
- Institute for Biology/Molecular Microbiology, Humboldt-Universität zu Berlin, Berlin10115, Germany
- Max Planck Unit for the Science of Pathogens, Berlin10117, Germany
| | - Christian Lesterlin
- Molecular Microbiology and Structural Biochemistry, Université Lyon 1, CNRS, Inserm, UMR5086, Lyon69007, France
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13
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Frankel G, David S, Low WW, Seddon C, Wong JC, Beis K. Plasmids pick a bacterial partner before committing to conjugation. Nucleic Acids Res 2023; 51:8925-8933. [PMID: 37592747 PMCID: PMC10516633 DOI: 10.1093/nar/gkad678] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 07/25/2023] [Accepted: 08/11/2023] [Indexed: 08/19/2023] Open
Abstract
Bacterial conjugation was first described by Lederberg and Tatum in the 1940s following the discovery of the F plasmid. During conjugation a plasmid is transferred unidirectionally from one bacterium (the donor) to another (the recipient), in a contact-dependent manner. Conjugation has been regarded as a promiscuous mechanism of DNA transfer, with host range determined by the recipient downstream of plasmid transfer. However, recent data have shown that F-like plasmids, akin to tailed Caudovirales bacteriophages, can pick their host bacteria prior to transfer by expressing one of at least four structurally distinct isoforms of the outer membrane protein TraN, which has evolved to function as a highly sensitive sensor on the donor cell surface. The TraN sensor appears to pick bacterial hosts by binding compatible outer membrane proteins in the recipient. The TraN variants can be divided into specialist and generalist sensors, conferring narrow and broad plasmid host range, respectively. In this review we discuss recent advances in our understanding of the function of the TraN sensor at the donor-recipient interface, used by F-like plasmids to select bacterial hosts within polymicrobial communities prior to DNA transfer.
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Affiliation(s)
- Gad Frankel
- Department of Life Sciences, Imperial College, London, UK
| | - Sophia David
- Centre for Genomic Pathogen Surveillance, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Wen Wen Low
- Department of Life Sciences, Imperial College, London, UK
| | - Chloe Seddon
- Department of Life Sciences, Imperial College, London, UK
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire OX11 0FA, UK
| | | | - Konstantinos Beis
- Department of Life Sciences, Imperial College, London, UK
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire OX11 0FA, UK
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14
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Meir A, Macé K, Vegunta Y, Williams SM, Waksman G. Substrate recruitment mechanism by gram-negative type III, IV, and VI bacterial injectisomes. Trends Microbiol 2023; 31:916-932. [PMID: 37085348 DOI: 10.1016/j.tim.2023.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 03/09/2023] [Accepted: 03/13/2023] [Indexed: 04/23/2023]
Abstract
Bacteria use a wide arsenal of macromolecular substrates (DNA and proteins) to interact with or infect prokaryotic and eukaryotic cells. To do so, they utilize substrate-injecting secretion systems or injectisomes. However, prior to secretion, substrates must be recruited to specialized recruitment platforms and then handed over to the secretion apparatus for secretion. In this review, we provide an update on recent advances in substrate recruitment and delivery by gram-negative bacterial recruitment platforms associated with Type III, IV, and VI secretion systems.
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Affiliation(s)
- Amit Meir
- Institute of Structural and Molecular Biology, Birkbeck and UCL, Malet Street, London WC1E 7HX, UK; Current address: MRC Centre for Virus Research, School of Infection and Immunity, University of Glasgow, Glasgow, UK.
| | - Kévin Macé
- Institute of Structural and Molecular Biology, Birkbeck and UCL, Malet Street, London WC1E 7HX, UK
| | - Yogesh Vegunta
- Institute of Structural and Molecular Biology, Birkbeck and UCL, Malet Street, London WC1E 7HX, UK
| | - Sunanda M Williams
- Institute of Structural and Molecular Biology, Birkbeck and UCL, Malet Street, London WC1E 7HX, UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, Birkbeck and UCL, Malet Street, London WC1E 7HX, UK; Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK.
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15
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Ryan ME, Damke PP, Bryant C, Sheedlo MJ, Shaffer CL. Architectural asymmetry enables DNA transport through the Helicobacter pylori cag type IV secretion system. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550604. [PMID: 37546756 PMCID: PMC10402047 DOI: 10.1101/2023.07.25.550604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Structural asymmetry within secretion system architecture is fundamentally important for apparatus diversification and biological function. However, the mechanism by which symmetry mismatch contributes to nanomachine assembly and interkingdom effector translocation are undefined. Here, we show that architectural asymmetry orchestrates dynamic substrate selection and enables trans-kingdom DNA conjugation through the Helicobacter pylori cag type IV secretion system (cag T4SS). Structural analyses of asymmetric units within the cag T4SS periplasmic ring complex (PRC) revealed intermolecular π-π stacking interactions that coordinate DNA binding and license trans-kingdom conjugation without disrupting the translocation of protein and peptidoglycan effector molecules. Additionally, we identified a novel proximal translocation channel gating mechanism that regulates cargo loading and governs substrate transport across the outer membrane. We thus propose a model whereby the organization and geometry of architectural symmetry mismatch exposes π-π interfaces within the PRC to facilitate DNA transit through the cag T4SS translocation channel.
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Affiliation(s)
- Mackenzie E. Ryan
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
| | - Prashant P. Damke
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, KY, 40546, USA
| | - Caitlynn Bryant
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, KY, 40546, USA
| | - Michael J. Sheedlo
- Department of Pharmacology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Carrie L. Shaffer
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, KY, 40546, USA
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, KY, 40536, USA
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
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16
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Shepherd DC, Kaplan M, Vankadari N, Kim KW, Larson CL, Dutka P, Beare PA, Krzymowski E, Heinzen RA, Jensen GJ, Ghosal D. Morphological remodeling of Coxiella burnetii during its biphasic developmental cycle revealed by cryo-electron tomography. iScience 2023; 26:107210. [PMID: 37485371 PMCID: PMC10362272 DOI: 10.1016/j.isci.2023.107210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/05/2023] [Accepted: 06/21/2023] [Indexed: 07/25/2023] Open
Abstract
Coxiella burnetii is an obligate zoonotic bacterium that targets macrophages causing a disease called Q fever. It has a biphasic developmental life cycle where the extracellular and metabolically inactive small cell variant (SCV) transforms inside the host into the vegetative large cell variant (LCV). However, details about the morphological and structural changes of this transition are still lacking. Here, we used cryo-electron tomography to image both SCV and LCV variants grown either under axenic conditions or purified directly from host cells. We show that SCVs are characterized by equidistant stacks of inner membrane that presumably facilitate the transition to LCV, a transition coupled with the expression of the Dot/Icm type IVB secretion system (T4BSS). A class of T4BSS particles were associated with extracellular densities possibly involved in host infection. Also, SCVs contained spherical multilayered membrane structures of different sizes and locations suggesting no connection to sporulation as once assumed.
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Affiliation(s)
- Doulin C. Shepherd
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Naveen Vankadari
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Ki Woo Kim
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- School of Ecology and Environmental System, Kyungpook National University, Sangju, Korea
| | - Charles L. Larson
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Przemysław Dutka
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Division od Chemistry and Chemical Engineering, California Institute of Technology, 1200 California Boulevard, Pasadena, CA 91125, USA
| | - Paul A. Beare
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Edward Krzymowski
- Department of Physics and Astronomy, Brigham Young University, Provo, UT 84604, USA
| | - Robert A. Heinzen
- Coxiella Pathogenesis Section, Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Grant J. Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84604, USA
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
- ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia
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17
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Ryan ME, Damke PP, Shaffer CL. DNA Transport through the Dynamic Type IV Secretion System. Infect Immun 2023; 91:e0043622. [PMID: 37338415 PMCID: PMC10353360 DOI: 10.1128/iai.00436-22] [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] [Indexed: 06/21/2023] Open
Abstract
The versatile type IV secretion system (T4SS) nanomachine plays a pivotal role in bacterial pathogenesis and the propagation of antibiotic resistance determinants throughout microbial populations. In addition to paradigmatic DNA conjugation machineries, diverse T4SSs enable the delivery of multifarious effector proteins to target prokaryotic and eukaryotic cells, mediate DNA export and uptake from the extracellular milieu, and in rare examples, facilitate transkingdom DNA translocation. Recent advances have identified new mechanisms underlying unilateral nucleic acid transport through the T4SS apparatus, highlighting both functional plasticity and evolutionary adaptations that enable novel capabilities. In this review, we describe the molecular mechanisms underscoring DNA translocation through diverse T4SS machineries, emphasizing the architectural features that implement DNA exchange across the bacterial membrane and license transverse DNA release across kingdom boundaries. We further detail how recent studies have addressed outstanding questions surrounding the mechanisms by which nanomachine architectures and substrate recruitment strategies contribute to T4SS functional diversity.
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Affiliation(s)
- Mackenzie E. Ryan
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Prashant P. Damke
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, Kentucky, USA
| | - Carrie L. Shaffer
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
- Department of Veterinary Sciences, University of Kentucky College of Agriculture, Lexington, Kentucky, USA
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, Kentucky, USA
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, Kentucky, USA
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18
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Conners R, León-Quezada RI, McLaren M, Bennett NJ, Daum B, Rakonjac J, Gold VAM. Cryo-electron microscopy of the f1 filamentous phage reveals insights into viral infection and assembly. Nat Commun 2023; 14:2724. [PMID: 37169795 PMCID: PMC10175506 DOI: 10.1038/s41467-023-37915-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 04/04/2023] [Indexed: 05/13/2023] Open
Abstract
Phages are viruses that infect bacteria and dominate every ecosystem on our planet. As well as impacting microbial ecology, physiology and evolution, phages are exploited as tools in molecular biology and biotechnology. This is particularly true for the Ff (f1, fd or M13) phages, which represent a widely distributed group of filamentous viruses. Over nearly five decades, Ffs have seen an extraordinary range of applications, yet the complete structure of the phage capsid and consequently the mechanisms of infection and assembly remain largely mysterious. In this work, we use cryo-electron microscopy and a highly efficient system for production of short Ff-derived nanorods to determine a structure of a filamentous virus including the tips. We show that structure combined with mutagenesis can identify phage domains that are important in bacterial attack and for release of new progeny, allowing new models to be proposed for the phage lifecycle.
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Affiliation(s)
- Rebecca Conners
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Rayén Ignacia León-Quezada
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
- Nanophage Technologies, Palmerston North, New Zealand
| | - Mathew McLaren
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Nicholas J Bennett
- School of Natural Sciences, Massey University, Palmerston North, New Zealand
| | - Bertram Daum
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Faculty of Health and Life Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Jasna Rakonjac
- School of Natural Sciences, Massey University, Palmerston North, New Zealand.
- Nanophage Technologies, Palmerston North, New Zealand.
| | - Vicki A M Gold
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
- Faculty of Health and Life Sciences, University of Exeter, Exeter, EX4 4QD, UK.
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19
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Blanc M, Lettl C, Guérin J, Vieille A, Furler S, Briand-Schumacher S, Dreier B, Bergé C, Plückthun A, Vadon-Le Goff S, Fronzes R, Rousselle P, Fischer W, Terradot L. Designed Ankyrin Repeat Proteins provide insights into the structure and function of CagI and are potent inhibitors of CagA translocation by the Helicobacter pylori type IV secretion system. PLoS Pathog 2023; 19:e1011368. [PMID: 37155700 DOI: 10.1371/journal.ppat.1011368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 05/18/2023] [Accepted: 04/18/2023] [Indexed: 05/10/2023] Open
Abstract
The bacterial human pathogen Helicobacter pylori produces a type IV secretion system (cagT4SS) to inject the oncoprotein CagA into gastric cells. The cagT4SS external pilus mediates attachment of the apparatus to the target cell and the delivery of CagA. While the composition of the pilus is unclear, CagI is present at the surface of the bacterium and required for pilus formation. Here, we have investigated the properties of CagI by an integrative structural biology approach. Using Alpha Fold 2 and Small Angle X-ray scattering, it was found that CagI forms elongated dimers mediated by rod-shape N-terminal domains (CagIN) prolonged by globular C-terminal domains (CagIC). Three Designed Ankyrin Repeat Proteins (DARPins) K2, K5 and K8 selected against CagI interacted with CagIC with subnanomolar affinities. The crystal structures of the CagI:K2 and CagI:K5 complexes were solved and identified the interfaces between the molecules, thereby providing a structural explanation for the difference in affinity between the two binders. Purified CagI and CagIC were found to interact with adenocarcinoma gastric (AGS) cells, induced cell spreading and the interaction was inhibited by K2. The same DARPin inhibited CagA translocation by up to 65% in AGS cells while inhibition levels were 40% and 30% with K8 and K5, respectively. Our study suggests that CagIC plays a key role in cagT4SS-mediated CagA translocation and that DARPins targeting CagI represent potent inhibitors of the cagT4SS, a crucial risk factor for gastric cancer development.
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Affiliation(s)
- Marine Blanc
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Clara Lettl
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Jérémy Guérin
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Anaïs Vieille
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Sven Furler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | | | - Birgit Dreier
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Célia Bergé
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
| | - Andreas Plückthun
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Sandrine Vadon-Le Goff
- University of Lyon, CNRS UMR5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), Lyon, France
| | - Rémi Fronzes
- European Institute of Chemistry and Biology, CNRS UMR 5234 Microbiologie Fondamentale et Pathogénicité, Univ. Bordeaux, Pessac, France
| | - Patricia Rousselle
- University of Lyon, CNRS UMR5305, Tissue Biology and Therapeutic Engineering Laboratory (LBTI), Lyon, France
| | - Wolfgang Fischer
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Laurent Terradot
- UMR 5086 Molecular Microbiology and Structural Biochemistry CNRS-Université de Lyon, Institut de Biologie et Chimie des Protéines, Lyon, France
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20
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Kreida S, Narita A, Johnson MD, Tocheva EI, Das A, Ghosal D, Jensen GJ. Cryo-EM structure of the Agrobacterium tumefaciens T4SS-associated T-pilus reveals stoichiometric protein-phospholipid assembly. Structure 2023; 31:385-394.e4. [PMID: 36870333 PMCID: PMC10168017 DOI: 10.1016/j.str.2023.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 01/08/2023] [Accepted: 02/07/2023] [Indexed: 03/06/2023]
Abstract
Agrobacterium tumefaciens causes crown gall disease in plants by the horizontal transfer of oncogenic DNA. The conjugation is mediated by the VirB/D4 type 4 secretion system (T4SS) that assembles an extracellular filament, the T-pilus, and is involved in mating pair formation between A. tumefaciens and the recipient plant cell. Here, we present a 3 Å cryoelectron microscopy (cryo-EM) structure of the T-pilus solved by helical reconstruction. Our structure reveals that the T-pilus is a stoichiometric assembly of the VirB2 major pilin and phosphatidylglycerol (PG) phospholipid with 5-start helical symmetry. We show that PG head groups and the positively charged Arg 91 residues of VirB2 protomers form extensive electrostatic interactions in the lumen of the T-pilus. Mutagenesis of Arg 91 abolished pilus formation. While our T-pilus structure is architecturally similar to previously published conjugative pili structures, the T-pilus lumen is narrower and positively charged, raising questions of whether the T-pilus is a conduit for ssDNA transfer.
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Affiliation(s)
- Stefan Kreida
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, 171 77 Stockholm, Sweden
| | - Akihiro Narita
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Matthew D Johnson
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Elitza I Tocheva
- Department of Microbiology and Immunology, Life Sciences Institute, The University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada
| | - Anath Das
- Department of Biochemistry, Molecular Biology and Biophysics, and Microbial and Plant Genomics Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia; ARC Centre for Cryo-electron Microscopy of Membrane Proteins, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC, Australia.
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84604, USA.
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21
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Patkowski JB, Dahlberg T, Amin H, Gahlot DK, Vijayrajratnam S, Vogel JP, Francis MS, Baker JL, Andersson M, Costa TRD. The F-pilus biomechanical adaptability accelerates conjugative dissemination of antimicrobial resistance and biofilm formation. Nat Commun 2023; 14:1879. [PMID: 37019921 PMCID: PMC10076315 DOI: 10.1038/s41467-023-37600-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 03/22/2023] [Indexed: 04/07/2023] Open
Abstract
Conjugation is used by bacteria to propagate antimicrobial resistance (AMR) in the environment. Central to this process are widespread conjugative F-pili that establish the connection between donor and recipient cells, thereby facilitating the spread of IncF plasmids among enteropathogenic bacteria. Here, we show that the F-pilus is highly flexible but robust at the same time, properties that increase its resistance to thermochemical and mechanical stresses. By a combination of biophysical and molecular dynamics methods, we establish that the presence of phosphatidylglycerol molecules in the F-pilus contributes to the structural stability of the polymer. Moreover, this structural stability is important for successful delivery of DNA during conjugation and facilitates rapid formation of biofilms in harsh environmental conditions. Thus, our work highlights the importance of F-pilus structural adaptations for the efficient spread of AMR genes in a bacterial population and for the formation of biofilms that protect against the action of antibiotics.
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Affiliation(s)
- Jonasz B Patkowski
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | - Tobias Dahlberg
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
| | - Himani Amin
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK
| | | | - Sukhithasri Vijayrajratnam
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joseph P Vogel
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Matthew S Francis
- Department of Molecular Biology, Umeå University, 901 87, Umeå, Sweden
| | - Joseph L Baker
- Department of Chemistry, The College of New Jersey, Ewing, NJ, 08628, USA.
| | | | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ, UK.
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22
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Beltran LC, Cvirkaite-Krupovic V, Miller J, Wang F, Kreutzberger MAB, Patkowski JB, Costa TRD, Schouten S, Levental I, Conticello VP, Egelman EH, Krupovic M. Archaeal DNA-import apparatus is homologous to bacterial conjugation machinery. Nat Commun 2023; 14:666. [PMID: 36750723 PMCID: PMC9905601 DOI: 10.1038/s41467-023-36349-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/27/2023] [Indexed: 02/09/2023] Open
Abstract
Conjugation is a major mechanism of horizontal gene transfer promoting the spread of antibiotic resistance among human pathogens. It involves establishing a junction between a donor and a recipient cell via an extracellular appendage known as the mating pilus. In bacteria, the conjugation machinery is encoded by plasmids or transposons and typically mediates the transfer of cognate mobile genetic elements. Much less is known about conjugation in archaea. Here, we determine atomic structures by cryo-electron microscopy of three conjugative pili, two from hyperthermophilic archaea (Aeropyrum pernix and Pyrobaculum calidifontis) and one encoded by the Ti plasmid of the bacterium Agrobacterium tumefaciens, and show that the archaeal pili are homologous to bacterial mating pili. However, the archaeal conjugation machinery, known as Ced, has been 'domesticated', that is, the genes for the conjugation machinery are encoded on the chromosome rather than on mobile genetic elements, and mediates the transfer of cellular DNA.
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Affiliation(s)
- Leticia C Beltran
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22903, USA
| | | | - Jessalyn Miller
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22903, USA.,Department of Biochemistry and Molecular Genetics, University of Alabama Birmingham, Birmingham, AL, 35233, USA
| | - Mark A B Kreutzberger
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22903, USA
| | - Jonasz B Patkowski
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, UK
| | - Stefan Schouten
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Texel, The Netherlands
| | - Ilya Levental
- Department of Molecular Physiology and Biological Physics, Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, 22903, USA
| | | | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22903, USA.
| | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, 75015, Paris, France.
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23
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Leprince A, Mahillon J. Phage Adsorption to Gram-Positive Bacteria. Viruses 2023; 15:196. [PMID: 36680236 PMCID: PMC9863714 DOI: 10.3390/v15010196] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 01/03/2023] [Accepted: 01/06/2023] [Indexed: 01/12/2023] Open
Abstract
The phage life cycle is a multi-stage process initiated by the recognition and attachment of the virus to its bacterial host. This adsorption step depends on the specific interaction between bacterial structures acting as receptors and viral proteins called Receptor Binding Proteins (RBP). The adsorption process is essential as it is the first determinant of phage host range and a sine qua non condition for the subsequent conduct of the life cycle. In phages belonging to the Caudoviricetes class, the capsid is attached to a tail, which is the central player in the adsorption as it comprises the RBP and accessory proteins facilitating phage binding and cell wall penetration prior to genome injection. The nature of the viral proteins involved in host adhesion not only depends on the phage morphology (i.e., myovirus, siphovirus, or podovirus) but also the targeted host. Here, we give an overview of the adsorption process and compile the available information on the type of receptors that can be recognized and the viral proteins taking part in the process, with the primary focus on phages infecting Gram-positive bacteria.
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24
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Shamir Y, Goldbourt A. Atomic-Resolution Structure of the Protein Encoded by Gene V of fd Bacteriophage in Complex with Viral ssDNA Determined by Magic-Angle Spinning Solid-State NMR. J Am Chem Soc 2022; 145:300-310. [PMID: 36542094 PMCID: PMC9837838 DOI: 10.1021/jacs.2c09957] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
F-specific filamentous phages, elongated particles with circular single-stranded DNA encased in a symmetric protein capsid, undergo an intermediate step, where thousands of homodimers of a non-structural protein, gVp, bind to newly synthesized strands of DNA, preventing further DNA replication and preparing the circular genome in an elongated conformation for assembly of a new virion structure at the membrane. While the structure of the free homodimer is known, the ssDNA-bound conformation has yet to be determined. We report an atomic-resolution structure of the gVp monomer bound to ssDNA of fd phage in the nucleoprotein complex elucidated via magic-angle spinning solid-state NMR. The model presents significant conformational changes with respect to the free form. These modifications facilitate the binding mechanism and possibly promote cooperative binding in the assembly of the gVp-ssDNA complex.
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25
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Cryo-EM structure of the Agrobacteriumtumefaciens T-pilus reveals the importance of positive charges in the lumen. Structure 2022; 31:375-384.e4. [PMID: 36513067 DOI: 10.1016/j.str.2022.11.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 09/19/2022] [Accepted: 11/14/2022] [Indexed: 12/14/2022]
Abstract
Agrobacterium tumefaciens is a natural genetic engineer that transfers DNA into plants, which is the most applied process for generation of genetically modified plants. DNA transfer is mediated by a type IV secretion system in the cell envelope and extracellular T-pili. We here report the cryo-electron microscopic structures of the T-pilus at 3.2-Å resolution and of the plasmid pKM101-determined N-pilus at 3-Å resolution. Both pili contain a main pilus protein (VirB2 in A. tumefaciens, TraM in pKM101) and phospholipids arranged in a five-start helical assembly. They contain positively charged amino acids in the lumen, and the lipids are positively charged in the T-pilus (phosphatidylcholine) conferring overall positive charge. Mutagenesis of the lumen-exposed Arg91 in VirB2 results in protein destabilization and loss of pilus formation. Our results reveal that different phospholipids can be incorporated into type IV secretion pili and that the charge of the lumen may be of functional importance.
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26
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The Effect of Heavy Metals on Conjugation Efficiency of an F-Plasmid in Escherichia coli. Antibiotics (Basel) 2022; 11:antibiotics11081123. [PMID: 36009992 PMCID: PMC9404890 DOI: 10.3390/antibiotics11081123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 11/16/2022] Open
Abstract
Conjugation, the process by which conjugative plasmids are transferred between bacteria, is regarded as a major contributor to the spread of antibiotic resistance, in both environmental and clinical settings. Heavy metals are known to co-select for antibiotic resistance, but the impact of the presence of these metals on conjugation itself is not clear. Here, we systematically investigate the impact that five heavy metals (arsenic, cadmium, copper, manganese, and zinc) have on the transfer of an IncF conjugative plasmid in Escherichia coli. Our results show that two of the metals, cadmium and manganese, have no significant impact, while arsenic and zinc both reduce conjugation efficiency by approximately 2-fold. Copper showed the largest impact, with an almost 100-fold decrease in conjugation efficiency. This was not mediated by any change in transcription from the major Py promoter responsible for transcription of the conjugation machinery genes. Further, we show that in order to have this severe impact on the transfer of the plasmid, copper sulfate needs to be present during the mating process, and we suggest explanations for this.
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27
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Chang L, Wang F, Connolly K, Meng H, Su Z, Cvirkaite-Krupovic V, Krupovic M, Egelman EH, Si D. DeepTracer-ID: De novo protein identification from cryo-EM maps. Biophys J 2022; 121:2840-2848. [PMID: 35769006 PMCID: PMC9388381 DOI: 10.1016/j.bpj.2022.06.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/04/2022] [Accepted: 06/23/2022] [Indexed: 11/02/2022] Open
Abstract
The recent revolution in cryo-electron microscopy (cryo-EM) has made it possible to determine macromolecular structures directly from cell extracts. However, identifying the correct protein from the cryo-EM map is still challenging and often needs additional sequence information from other techniques, such as tandem mass spectrometry and/or bioinformatics. Here, we present DeepTracer-ID, a server-based approach to identify the candidate protein in a user-provided organism de novo from a cryo-EM map, without the need for additional information. Our method first uses DeepTracer to generate a protein backbone model that best represents the cryo-EM map, and this model is then searched against the library of AlphaFold2 predictions for all proteins in the given organism. This method is highly accurate and robust for high-resolution cryo-EM maps: in all 13 experimental maps tested blindly, DeepTracer-ID identified the correct proteins as the top candidates. Eight of the maps were of known structures, while the other five unpublished maps were validated by prior protein annotation and careful inspection of the model refined into the map. The program also showed promising results for both homomeric and heteromeric protein complexes. This platform is possible because of the recent breakthroughs in large-scale three-dimensional protein structure prediction.
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Affiliation(s)
- Luca Chang
- Division of Computing and Software Systems, University of Washington Bothell, Bothell, Washington
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia.
| | - Kiernan Connolly
- Division of Computing and Software Systems, University of Washington Bothell, Bothell, Washington
| | - Hanze Meng
- Department of Mathematics, University of Washington, Seattle, Washington
| | - Zhangli Su
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | | | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, Paris, France
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia.
| | - Dong Si
- Division of Computing and Software Systems, University of Washington Bothell, Bothell, Washington.
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28
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Abstract
Bacterial type IV secretion systems (T4SSs) are a versatile group of nanomachines that can horizontally transfer DNA through conjugation and deliver effector proteins into a wide range of target cells. The components of T4SSs in gram-negative bacteria are organized into several large subassemblies: an inner membrane complex, an outer membrane core complex, and, in some species, an extracellular pilus. Cryo-electron tomography has been used to define the structures of T4SSs in intact bacteria, and high-resolution structural models are now available for isolated core complexes from conjugation systems, the Xanthomonas citri T4SS, the Helicobacter pylori Cag T4SS, and the Legionella pneumophila Dot/Icm T4SS. In this review, we compare the molecular architectures of these T4SSs, focusing especially on the structures of core complexes. We discuss structural features that are shared by multiple T4SSs as well as evolutionary strategies used for T4SS diversification. Finally, we discuss how structural variations among T4SSs may confer specialized functional properties.
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Affiliation(s)
- Michael J. Sheedlo
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Melanie D. Ohi
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
| | - D. Borden Lacy
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
| | - Timothy L. Cover
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, United States of America
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
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29
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Low WW, Wong JLC, Beltran LC, Seddon C, David S, Kwong HS, Bizeau T, Wang F, Peña A, Costa TRD, Pham B, Chen M, Egelman EH, Beis K, Frankel G. Mating pair stabilization mediates bacterial conjugation species specificity. Nat Microbiol 2022; 7:1016-1027. [PMID: 35697796 PMCID: PMC9246713 DOI: 10.1038/s41564-022-01146-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 05/05/2022] [Indexed: 11/30/2022]
Abstract
Bacterial conjugation mediates contact-dependent transfer of DNA from donor to recipient bacteria, thus facilitating the spread of virulence and resistance plasmids. Here we describe how variants of the plasmid-encoded donor outer membrane (OM) protein TraN cooperate with distinct OM receptors in recipients to mediate mating pair stabilization and efficient DNA transfer. We show that TraN from the plasmid pKpQIL (Klebsiella pneumoniae) interacts with OmpK36, plasmids from R100-1 (Shigella flexneri) and pSLT (Salmonella Typhimurium) interact with OmpW, and the prototypical F plasmid (Escherichia coli) interacts with OmpA. Cryo-EM analysis revealed that TraNpKpQIL interacts with OmpK36 through the insertion of a β-hairpin in the tip of TraN into a monomer of the OmpK36 porin trimer. Combining bioinformatic analysis with AlphaFold structural predictions, we identified a fourth TraN structural variant that mediates mating pair stabilization by binding OmpF. Accordingly, we devised a classification scheme for TraN homologues on the basis of structural similarity and their associated receptors: TraNα (OmpW), TraNβ (OmpK36), TraNγ (OmpA), TraNδ (OmpF). These TraN-OM receptor pairings have real-world implications as they reflect the distribution of resistance plasmids within clinical Enterobacteriaceae isolates, demonstrating the importance of mating pair stabilization in mediating conjugation species specificity. These findings will allow us to predict the distribution of emerging resistance plasmids in high-risk bacterial pathogens. Combining conjugation and structural analyses, the authors show that TraN-OMP pairings determine bacterial conjugation species specificity, with implications in resistance plasmid distribution within Enterobacteriaceae.
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Affiliation(s)
- Wen Wen Low
- MRC Centre for Molecular Microbiology and Infection, Imperial College, London, UK.,Department of Life Sciences, Imperial College, London, UK
| | - Joshua L C Wong
- MRC Centre for Molecular Microbiology and Infection, Imperial College, London, UK.,Department of Life Sciences, Imperial College, London, UK
| | - Leticia C Beltran
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Chloe Seddon
- MRC Centre for Molecular Microbiology and Infection, Imperial College, London, UK.,Department of Life Sciences, Imperial College, London, UK.,Rutherford Appleton Laboratory, Research Complex at Harwell, Oxfordshire, UK
| | - Sophia David
- Centre for Genomic Pathogen Surveillance, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, Oxford, UK
| | - Hok-Sau Kwong
- Department of Life Sciences, Imperial College, London, UK.,Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Tatiana Bizeau
- Department of Life Sciences, Imperial College, London, UK
| | - Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Alejandro Peña
- MRC Centre for Molecular Microbiology and Infection, Imperial College, London, UK.,Department of Life Sciences, Imperial College, London, UK
| | - Tiago R D Costa
- MRC Centre for Molecular Microbiology and Infection, Imperial College, London, UK.,Department of Life Sciences, Imperial College, London, UK
| | - Bach Pham
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA, USA
| | - Min Chen
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, USA
| | - Konstantinos Beis
- Department of Life Sciences, Imperial College, London, UK.,Rutherford Appleton Laboratory, Research Complex at Harwell, Oxfordshire, UK
| | - Gad Frankel
- MRC Centre for Molecular Microbiology and Infection, Imperial College, London, UK. .,Department of Life Sciences, Imperial College, London, UK.
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30
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Abstract
Bacterial conjugation is the fundamental process of unidirectional transfer of DNAs, often plasmid DNAs, from a donor cell to a recipient cell1. It is the primary means by which antibiotic resistance genes spread among bacterial populations2,3. In Gram-negative bacteria, conjugation is mediated by a large transport apparatus—the conjugative type IV secretion system (T4SS)—produced by the donor cell and embedded in both its outer and inner membranes. The T4SS also elaborates a long extracellular filament—the conjugative pilus—that is essential for DNA transfer4,5. Here we present a high-resolution cryo-electron microscopy (cryo-EM) structure of a 2.8 megadalton T4SS complex composed of 92 polypeptides representing 8 of the 10 essential T4SS components involved in pilus biogenesis. We added the two remaining components to the structural model using co-evolution analysis of protein interfaces, to enable the reconstitution of the entire system including the pilus. This structure describes the exceptionally large protein–protein interaction network required to assemble the many components that constitute a T4SS and provides insights on the unique mechanism by which they elaborate pili. Cryo-electron microscopy structures of a 2.8 megadalton bacterial type IV secretion system encoded by the plasmid R388 and comprising 92 polypeptides provide insights into the stepwise mechanism of pilus assembly.
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31
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Conformational Changes in Ff Phage Protein gVp upon Complexation with Its Viral Single-Stranded DNA Revealed Using Magic-Angle Spinning Solid-State NMR. Viruses 2022; 14:v14061264. [PMID: 35746735 PMCID: PMC9231167 DOI: 10.3390/v14061264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/04/2022] [Accepted: 06/05/2022] [Indexed: 02/04/2023] Open
Abstract
Gene V protein (gVp) of the bacteriophages of the Ff family is a non-specific single-stranded DNA (ssDNA) binding protein. gVp binds to viral DNA during phage replication inside host Escherichia coli cells, thereby blocking further replication and signaling the assembly of new phage particles. gVp is a dimer in solution and in crystal form. A structural model of the complex between gVp and ssDNA was obtained via docking the free gVp to structures of short ssDNA segments and via the detection of residues involved in DNA binding in solution. Using solid-state NMR, we characterized structural features of the gVp in complex with full-length viral ssDNA. We show that gVp binds ssDNA with an average distance of 5.5 Å between the amino acid residues of the protein and the phosphate backbone of the DNA. Torsion angle predictions and chemical shift perturbations indicate that there were considerable structural changes throughout the protein upon complexation with ssDNA, with the most significant variations occurring at the ssDNA binding loop and the C-terminus. Our data suggests that the structure of gVp in complex with ssDNA differs significantly from the structure of gVp in the free form, presumably to allow for cooperative binding of dimers to form the filamentous phage particle.
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32
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Zhang G, Chen J, Li W. Conjugative antibiotic-resistant plasmids promote bacterial colonization of microplastics in water environments. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128443. [PMID: 35152101 DOI: 10.1016/j.jhazmat.2022.128443] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/25/2022] [Accepted: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Both microplastic and bacterial antibiotic resistance have attracted attention worldwide. When microplastics coexist with antibiotic-resistant bacteria (ARB), which carry antibiotic resistance genes (ARGs), ARB colonize the surface of microplastics, and a unique biofilm is formed. The ARB and ARGs in biofilms are denser and more difficult to remove. However, studies on the factors influencing the formation of microplastic biofilms are limited. In this study, plasmid RP4, which appeared in wastewater treatment plants, was found to be able to promote irreversible bacterial colonization of microplastics, and the hypothetical reason was conjugative pili expression. Then, the potential conjugative pili synthesis promoter "nanoalumina" and inhibitor "free nitrous acid" (FNA) were selected to test this hypothesis. Simultaneously, nanoalumina promoted and FNA inhibited bacterial colonization when RP4 existed. Combined with the gene expression and ATP analysis results, this hypothesis was confirmed, and the mechanism of RP4 on bacterial colonization was related mainly to conjugative pili protein synthesis and intracellular ATP. In this study, the effects of plasmid RP4, nanoalumina, and FNA on the formation of microplastic biofilms were reported, which has a certain reference value for other researchers exploring microplastic biofilms.
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Affiliation(s)
- Guosheng Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Jiping Chen
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China
| | - Weiying Li
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, 200092 Shanghai, China.
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33
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Kishida K, Bosserman RE, Harb L, Khara P, Song L, Hu B, Zeng L, Christie PJ. Contributions of F‐specific Subunits to the F
Plasmid‐Encoded
Type
IV
Secretion System and F pilus. Mol Microbiol 2022; 117:1275-1290. [DOI: 10.1111/mmi.14908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/26/2022] [Accepted: 04/12/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Kouhei Kishida
- Department of Microbiology and Molecular Genetics McGovern Medical School 6431 Fannin St, Houston, Texas 77030
| | - Rachel E. Bosserman
- Department of Microbiology and Molecular Genetics McGovern Medical School 6431 Fannin St, Houston, Texas 77030
- Current address: Department of Medicine, Division of Infectious Diseases Washington School of Medicine St. Louis, MO, 63110
| | - Laith Harb
- Department of Biochemistry and Biophysics, Texas A&M University College Station TX, 77843 USA
- Center for Phage Technology, Texas A&M University College Station TX, 77843 USA
| | - Pratick Khara
- Department of Microbiology and Molecular Genetics McGovern Medical School 6431 Fannin St, Houston, Texas 77030
| | - Liqiang Song
- Department of Microbiology and Molecular Genetics McGovern Medical School 6431 Fannin St, Houston, Texas 77030
| | - Bo Hu
- Department of Microbiology and Molecular Genetics McGovern Medical School 6431 Fannin St, Houston, Texas 77030
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Texas A&M University College Station TX, 77843 USA
- Center for Phage Technology, Texas A&M University College Station TX, 77843 USA
| | - Peter J. Christie
- Department of Microbiology and Molecular Genetics McGovern Medical School 6431 Fannin St, Houston, Texas 77030
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34
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Spindle-shaped archaeal viruses evolved from rod-shaped ancestors to package a larger genome. Cell 2022; 185:1297-1307.e11. [PMID: 35325592 PMCID: PMC9018610 DOI: 10.1016/j.cell.2022.02.019] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 01/23/2022] [Accepted: 02/15/2022] [Indexed: 11/22/2022]
Abstract
Spindle- or lemon-shaped viruses infect archaea in diverse environments. Due to the highly pleomorphic nature of these virions, which can be found with cylindrical tails emanating from the spindle-shaped body, structural studies of these capsids have been challenging. We have determined the atomic structure of the capsid of Sulfolobus monocaudavirus 1, a virus that infects hosts living in nearly boiling acid. A highly hydrophobic protein, likely integrated into the host membrane before the virions assemble, forms 7 strands that slide past each other in both the tails and the spindle body. We observe the discrete steps that occur as the tail tubes expand, and these are due to highly conserved quasiequivalent interactions with neighboring subunits maintained despite significant diameter changes. Our results show how helical assemblies can vary their diameters, becoming nearly spherical to package a larger genome and suggest how all spindle-shaped viruses have evolved from archaeal rod-like viruses.
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35
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Miller JG, Hughes SA, Modlin C, Conticello VP. Structures of synthetic helical filaments and tubes based on peptide and peptido-mimetic polymers. Q Rev Biophys 2022; 55:1-103. [PMID: 35307042 DOI: 10.1017/s0033583522000014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractSynthetic peptide and peptido-mimetic filaments and tubes represent a diverse class of nanomaterials with a broad range of potential applications, such as drug delivery, vaccine development, synthetic catalyst design, encapsulation, and energy transduction. The structures of these filaments comprise supramolecular polymers based on helical arrangements of subunits that can be derived from self-assembly of monomers based on diverse structural motifs. In recent years, structural analyses of these materials at near-atomic resolution (NAR) have yielded critical insights into the relationship between sequence, local conformation, and higher-order structure and morphology. This structural information offers the opportunity for development of new tools to facilitate the predictable and reproduciblede novodesign of synthetic helical filaments. However, these studies have also revealed several significant impediments to the latter process – most notably, the common occurrence of structural polymorphism due to the lability of helical symmetry in structural space. This article summarizes the current state of knowledge on the structures of designed peptide and peptido-mimetic filamentous assemblies, with a focus on structures that have been solved to NAR for which reliable atomic models are available.
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Affiliation(s)
- Jessalyn G Miller
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA30322
| | - Spencer A Hughes
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA30322
| | - Charles Modlin
- Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA30322
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36
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Garnett JA, Atherton J. Structure Determination of Microtubules and Pili: Past, Present, and Future Directions. Front Mol Biosci 2022; 8:830304. [PMID: 35096976 PMCID: PMC8795688 DOI: 10.3389/fmolb.2021.830304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 12/28/2021] [Indexed: 11/30/2022] Open
Abstract
Historically proteins that form highly polymeric and filamentous assemblies have been notoriously difficult to study using high resolution structural techniques. This has been due to several factors that include structural heterogeneity, their large molecular mass, and available yields. However, over the past decade we are now seeing a major shift towards atomic resolution insight and the study of more complex heterogenous samples and in situ/ex vivo examination of multi-subunit complexes. Although supported by developments in solid state nuclear magnetic resonance spectroscopy (ssNMR) and computational approaches, this has primarily been due to advances in cryogenic electron microscopy (cryo-EM). The study of eukaryotic microtubules and bacterial pili are good examples, and in this review, we will give an overview of the technical innovations that have enabled this transition and highlight the advancements that have been made for these two systems. Looking to the future we will also describe systems that remain difficult to study and where further technical breakthroughs are required.
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Affiliation(s)
- James A. Garnett
- Centre for Host-Microbiome Interactions, Faculty of Dental, Oral and Craniofacial Sciences, King’s College London, London, United Kingdom
| | - Joseph Atherton
- Randall Centre for Cell and Molecular Biophysics, King’s College London, London, United Kingdom
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37
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Structural basis for effector recognition by an antibacterial type IV secretion system. Proc Natl Acad Sci U S A 2022; 119:2112529119. [PMID: 34983846 PMCID: PMC8740702 DOI: 10.1073/pnas.2112529119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2021] [Indexed: 11/19/2022] Open
Abstract
Type IV secretion systems (T4SSs) have been studied for more than 70 y because of their roles in mediating horizontal DNA transfer, responsible for the spread of antibiotic resistance, and the injection of virulence factors into animal and plant hosts. Another important function is the contact-dependent injection of toxic effectors into competing bacteria of different species during bacterial warfare. The present study reveals how T4SSs use a specific domain of the VirD4 coupling protein to recruit antibacterial toxins for secretion by recognizing conserved carboxyl-terminal secretion signal domains. The molecular structure of the secretion signal domain described in this work will serve as a model for thousands of homologs encountered in several hundred distinct bacterial species. Many soil-, water-, and plant-associated bacterial species from the orders Xanthomonadales, Burkholderales, and Neisseriales carry a type IV secretion system (T4SS) specialized in translocating effector proteins into other gram-negative species, leading to target cell death. These effectors, known as X-Tfes, carry a carboxyl-terminal domain of ∼120 residues, termed XVIPCD, characterized by several conserved motifs and a glutamine-rich tail. Previous studies showed that the XVIPCD is required for interaction with the T4SS coupling protein VirD4 and for T4SS-dependent translocation. However, the structural basis of the XVIPCD–VirD4 interaction is unknown. Here, we show that the XVIPCD interacts with the central all-alpha domain of VirD4 (VirD4AAD). We used solution NMR spectroscopy to solve the structure of the XVIPCD of X-TfeXAC2609 from Xanthomonas citri and to map its interaction surface with VirD4AAD. Isothermal titration calorimetry and in vivo Xanthomonas citri versus Escherichia coli competition assays using wild-type and mutant X-TfeXAC2609 and X-TfeXAC3634 indicate that XVIPCDs can be divided into two regions with distinct functions: the well-folded N-terminal region contains specific conserved motifs that are responsible for interactions with VirD4AAD, while both N- and carboxyl-terminal regions are required for effective X-Tfe translocation into the target cell. The conformational stability of the N-terminal region is reduced at and below pH 7.0, a property that may facilitate X-Tfe unfolding and translocation through the more acidic environment of the periplasm.
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38
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Goldlust K, Couturier A, Terradot L, Lesterlin C. Live-Cell Visualization of DNA Transfer and Pilus Dynamics During Bacterial Conjugation. Methods Mol Biol 2022; 2476:63-74. [PMID: 35635697 DOI: 10.1007/978-1-0716-2221-6_6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Bacterial genomes are highly plastic and evolve rapidly by acquiring new genetic information through horizontal gene transfer mechanisms. Capturing DNA transfer by conjugation between bacterial cells in real time is relevant to address bacterial genomes' dynamic architecture comprehensively. Here, we describe a method allowing the direct visualization of bacterial conjugation in live cells, including the fluorescent labeling of the conjugative pilus and the monitoring of plasmid DNA transfer from donor to recipient cells.
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Affiliation(s)
- Kelly Goldlust
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon Cedex 07, France
| | - Agathe Couturier
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon Cedex 07, France
| | - Laurent Terradot
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon Cedex 07, France
| | - Christian Lesterlin
- Microbiologie Moléculaire et Biochimie Structurale (MMSB), Université Lyon 1, CNRS, Inserm, UMR5086, Lyon Cedex 07, France.
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39
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Amin H, Ilangovan A, Costa TRD. Architecture of the outer-membrane core complex from a conjugative type IV secretion system. Nat Commun 2021; 12:6834. [PMID: 34824240 PMCID: PMC8617172 DOI: 10.1038/s41467-021-27178-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/03/2021] [Indexed: 11/30/2022] Open
Abstract
Conjugation is one of the most important processes that bacteria utilize to spread antibiotic resistance genes among bacterial populations. Interbacterial DNA transfer requires a large double membrane-spanning nanomachine called the type 4 secretion system (T4SS) made up of the inner-membrane complex (IMC), the outer-membrane core complex (OMCC) and the conjugative pilus. The iconic F plasmid-encoded T4SS has been central in understanding conjugation for several decades, however atomic details of its structure are not known. Here, we report the structure of a complete conjugative OMCC encoded by the pED208 plasmid from E. coli, solved by cryo-electron microscopy at 3.3 Å resolution. This 2.1 MDa complex has a unique arrangement with two radial concentric rings, each having a different symmetry eventually contributing to remarkable differences in protein stoichiometry and flexibility in comparison to other OMCCs. Our structure suggests that F-OMCC is a highly dynamic complex, with implications for pilus extension and retraction during conjugation.
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Affiliation(s)
- Himani Amin
- grid.7445.20000 0001 2113 8111MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ UK
| | - Aravindan Ilangovan
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK.
| | - Tiago R. D. Costa
- grid.7445.20000 0001 2113 8111MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College, London, SW7 2AZ UK
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40
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Shepherd DC, Dalvi S, Ghosal D. From cells to atoms: Cryo-EM as an essential tool to investigate pathogen biology, host-pathogen interaction, and drug discovery. Mol Microbiol 2021; 117:610-617. [PMID: 34592048 DOI: 10.1111/mmi.14820] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 09/23/2021] [Indexed: 01/18/2023]
Abstract
Electron cryo-microscopy (cryo-EM) has lately emerged as a powerful method in structural biology and cell biology. While cryo-EM single-particle analysis (SPA) is now routinely delivering structures of purified proteins and protein complexes at near-atomic resolution, the use of electron cryo-tomography (cryo-ET), together with subtomogram averaging, is allowing visualization of macromolecular complexes in their native cellular environment, at unprecedented resolution. The unique ability of cryo-EM to provide information at many spatial resolution scales from ångströms to microns makes it an invaluable tool that bridges the classic "resolution-gap" between structural biology and cell biology domains. Like in many other fields of biology, in recent years, cryo-EM has revolutionized our understanding of pathogen biology, host-pathogen interaction and has made significant strides toward structure-based drug discovery. In a very recent example, during the ongoing coronavirus disease (COVID-19) pandemic, the structure of the stabilized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein was deciphered by SPA. This led to the development of multiple vaccines. Alongside, cryo-ET provided key insights into the structure of the native virion, mechanism of its entry, replication, and budding; demonstrating the unrivaled power of cryo-EM in investigating pathogen biology, host-pathogen interaction, and drug discovery. In this review, we showcase a few examples of how different imaging modalities within cryo-EM have enabled the study of microbiology and host-pathogen interaction.
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Affiliation(s)
- Doulin C Shepherd
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Somavally Dalvi
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
| | - Debnath Ghosal
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, Australia
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41
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Cai X, Liu L, Qiu C, Wen C, He Y, Cui Y, Li S, Zhang X, Zhang L, Tian C, Bi L, Zhou ZH, Gong W. Identification and architecture of a putative secretion tube across mycobacterial outer envelope. SCIENCE ADVANCES 2021; 7:7/34/eabg5656. [PMID: 34417177 PMCID: PMC8378821 DOI: 10.1126/sciadv.abg5656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Tuberculosis-causing mycobacteria have thick cell-wall and capsule layers that are formed from complex structures. Protein secretion across these barriers depends on a specialized protein secretion system, but none has been reported. We show that Mycobacterium tuberculosis Rv3705c and its homologous MSMEG_6251 in Mycobacterium smegmatis are tube-forming proteins in the mycobacterial envelope (TiME). Crystallographic and cryo-EM structures of these two proteins show that both proteins form rotationally symmetric rings. Two layers of TiME rings pack together in a tail-to-tail manner into a ring-shaped complex, which, in turn, stacks together to form tubes. M. smegmatis TiME was detected mainly in the cell wall and capsule. Knocking out the TiME gene markedly decreased the amount of secreted protein in the M. smegmatis culture medium, and expression of this gene in knocked-out strain partially restored the level of secreted protein. Our structure and functional data thus suggest that TiME forms a protein transport tube across the mycobacterial outer envelope.
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Affiliation(s)
- Xiaoying Cai
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Lei Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
| | - Chunhong Qiu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Chongzheng Wen
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
| | - Yao He
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA
| | - Yanxiang Cui
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Siyu Li
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Xuan Zhang
- Institute of Health Science, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, China
| | - Longhua Zhang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Changlin Tian
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
| | - Lijun Bi
- Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Z Hong Zhou
- California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA.
- Department of Microbiology, Immunology and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA
| | - Weimin Gong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, China
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42
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Exploiting pilus-mediated bacteria-host interactions for health benefits. Mol Aspects Med 2021; 81:100998. [PMID: 34294411 DOI: 10.1016/j.mam.2021.100998] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/30/2021] [Accepted: 07/16/2021] [Indexed: 02/06/2023]
Abstract
Surface pili (or fimbriae) are an important but conspicuous adaptation of several genera and species of Gram-negative and Gram-positive bacteria. These long and non-flagellar multi-subunit adhesins mediate the initial contact that a bacterium has with a host or environment, and thus have come to be regarded as a key colonization factor for virulence activity in pathogens or niche adaptation in commensals. Pili in pathogenic bacteria are well recognized for their roles in the adhesion to host cells, colonization of tissues, and establishment of infection. As an 'anti-adhesive' ploy, targeting pilus-mediated attachment for disruption has become a potentially effective alternative to using antibiotics. In this review, we give a description of the several structurally distinct bacterial pilus types thus far characterized, and as well offer details about the intricacy of their individual structure, assembly, and function. With a molecular understanding of pilus biogenesis and pilus-mediated host interactions also provided, we go on to describe some of the emerging new approaches and compounds that have been recently developed to prevent the adhesion, colonization, and infection of piliated bacterial pathogens.
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43
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Cover TL. Tracking bacterial effector protein delivery into host cells. Mol Microbiol 2021; 116:724-728. [PMID: 34250669 DOI: 10.1111/mmi.14784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/08/2021] [Indexed: 11/29/2022]
Abstract
Bacterial Type IV secretion systems (T4SSs) are a functionally heterogeneous group of nanomachines that can deliver substrates into a wide range of target cells. The Helicobacter pylori Cag T4SS has an important role in the pathogenesis of gastric cancer. CagA, the only effector protein known to be secreted by the H. pylori Cag T4SS, enters human gastric cells and causes alterations in intracellular signaling that are linked to cancer pathogenesis. Understanding the molecular mechanisms by which CagA is delivered into gastric cells has been hindered by the lack of robust methods for monitoring this process. A publication in this issue of Molecular Microbiology describes a split luciferase assay for monitoring T4SS-mediated translocation of CagA into host cells. The use of this translocation reporter allowed the quantification of CagA translocation in real-time assays, thereby facilitating the analysis of the kinetics of CagA delivery. This system also allowed the tracking of several types of CagA fusion proteins and confirmed that protein unfolding is important for secretion by the Cag T4SS. This commentary discusses T4SS-dependent delivery of H. pylori CagA into host cells and the use of the split luciferase system for monitoring bacterial protein secretion and delivery into target cells.
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Affiliation(s)
- Timothy L Cover
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.,Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.,Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN, USA
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44
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Dowhan W, Bogdanov M. Eugene P. Kennedy's Legacy: Defining Bacterial Phospholipid Pathways and Function. Front Mol Biosci 2021; 8:666203. [PMID: 33842554 PMCID: PMC8027125 DOI: 10.3389/fmolb.2021.666203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 03/01/2021] [Indexed: 12/27/2022] Open
Abstract
In the 1950's and 1960's Eugene P. Kennedy laid out the blueprint for phospholipid biosynthesis in somatic cells and Escherichia coli, which have been coined the Kennedy Pathways for phospholipid biosynthesis. His research group continued to make seminal contributions in the area of phospholipids until his retirement in the early 1990's. During these years he mentored many young scientists that continued to build on his early discoveries and who also mentored additional scientists that continue to make important contributions in areas related to phospholipids and membrane biogenesis. This review will focus on the initial E. coli Kennedy Pathways and how his early contributions have laid the foundation for our current understanding of bacterial phospholipid genetics, biochemistry and function as carried on by his scientific progeny and others who have been inspired to study microbial phospholipids.
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Affiliation(s)
- William Dowhan
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
| | - Mikhail Bogdanov
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center, Houston, TX, United States
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45
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Hancock SJ, Phan MD, Roberts LW, Vu TNM, Harris PNA, Beatson SA, Schembri MA. Characterization of DtrJ as an IncC plasmid conjugative DNA transfer component. Mol Microbiol 2021; 116:154-167. [PMID: 33567150 DOI: 10.1111/mmi.14697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 02/08/2021] [Indexed: 11/30/2022]
Abstract
Incompatibility group C (IncC) plasmids are large (50-400 kb), broad host range plasmids that drive the spread of genes conferring resistance to all classes of antibiotics, most notably the blaNDM gene that confers resistance to last-line carbapenems and the mcr-3 gene that confers resistance to colistin. Several recent studies have improved our understanding of the basic biological mechanisms driving the success of IncC, in particular the identification of multiple novel IncC conjugation genes by transposon directed insertion-site sequencing. Here, one of these genes, dtrJ, was examined in further detail. The dtrJ gene is located in the DNA transfer locus on the IncC backbone, and quantitative reverse-transcriptase PCR analysis revealed it is transcribed in the same operon as the DNA transfer genes traI and traD (encoding the relaxase and coupling protein, respectively) and activated by the AcaDC regulatory complex. We confirmed that DtrJ is not required for pilus biogenesis or mate pair formation. Instead, DtrJ localizes to the membrane, where it interacts with the coupling protein TraD and functions as an IncC DNA transfer protein. Overall, this work has defined the role of DtrJ in DNA transfer of IncC plasmids during conjugation.
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Affiliation(s)
- Steven J Hancock
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Leah W Roberts
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Thu Ngoc Minh Vu
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia.,College of Agriculture, Can Tho University, Can Tho City, Vietnam
| | - Patrick N A Harris
- Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia.,The University of Queensland Centre for Clinical Research, Brisbane, QLD, Australia
| | - Scott A Beatson
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, Australia.,Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
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46
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Protein Export via the Type III Secretion System of the Bacterial Flagellum. Biomolecules 2021; 11:biom11020186. [PMID: 33572887 PMCID: PMC7911332 DOI: 10.3390/biom11020186] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 12/15/2022] Open
Abstract
The bacterial flagellum and the related virulence-associated injectisome system of pathogenic bacteria utilize a type III secretion system (T3SS) to export substrate proteins across the inner membrane in a proton motive force-dependent manner. The T3SS is composed of an export gate (FliPQR/FlhA/FlhB) located in the flagellar basal body and an associated soluble ATPase complex in the cytoplasm (FliHIJ). Here, we summarise recent insights into the structure, assembly and protein secretion mechanisms of the T3SS with a focus on energy transduction and protein transport across the cytoplasmic membrane.
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47
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Darphorn TS, Bel K, Koenders-van Sint Anneland BB, Brul S, Ter Kuile BH. Antibiotic resistance plasmid composition and architecture in Escherichia coli isolates from meat. Sci Rep 2021; 11:2136. [PMID: 33483623 PMCID: PMC7822866 DOI: 10.1038/s41598-021-81683-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/08/2021] [Indexed: 01/30/2023] Open
Abstract
Resistance plasmids play a crucial role in the transfer of antimicrobial resistance from the veterinary sector to human healthcare. In this study plasmids from foodborne Escherichia coli isolates with a known (ES)BL or tetracycline resistance were sequenced entirely with short- and long-read technologies to obtain insight into their composition and to identify driving factors for spreading. Resistant foodborne E. coli isolates often contained several plasmids coding for resistance to various antimicrobials. Most plasmids were large and contained multiple resistance genes in addition to the selected resistance gene. The majority of plasmids belonged to the IncI, IncF and IncX incompatibility groups. Conserved and variable regions could be distinguished in each of the plasmid groups. Clusters containing resistance genes were located in the variable regions. Tetracycline and (extended spectrum) beta-lactamase resistance genes were each situated in separate clusters, but sulphonamide, macrolide and aminoglycoside formed one cluster and lincosamide and aminoglycoside another. In most plasmids, addiction systems were found to maintain presence in the cell.
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Affiliation(s)
- Tania S. Darphorn
- grid.7177.60000000084992262Laboratory for Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Keshia Bel
- grid.7177.60000000084992262Laboratory for Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands ,grid.4818.50000 0001 0791 5666Present Address: Wageningen Food Safety Research, Wageningen University and Research, Postbus 230, 6700 AE Wageningen, The Netherlands
| | - Belinda B. Koenders-van Sint Anneland
- grid.7177.60000000084992262Laboratory for Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Stanley Brul
- grid.7177.60000000084992262Laboratory for Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Benno H. Ter Kuile
- grid.7177.60000000084992262Laboratory for Molecular Biology and Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands ,grid.435742.30000 0001 0726 7822Netherlands Food and Consumer Product Safety Authority, Office for Risk Assessment, Utrecht, The Netherlands
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48
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Tittes C, Schwarzer S, Quax TEF. Viral Hijack of Filamentous Surface Structures in Archaea and Bacteria. Viruses 2021; 13:v13020164. [PMID: 33499367 PMCID: PMC7911016 DOI: 10.3390/v13020164] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 12/30/2022] Open
Abstract
The bacterial and archaeal cell surface is decorated with filamentous surface structures that are used for different functions, such as motility, DNA exchange and biofilm formation. Viruses hijack these structures and use them to ride to the cell surface for successful entry. In this review, we describe currently known mechanisms for viral attachment, translocation, and entry via filamentous surface structures. We describe the different mechanisms used to exploit various surface structures bacterial and archaeal viruses. This overview highlights the importance of filamentous structures at the cell surface for entry of prokaryotic viruses.
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49
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Wang F, Gnewou O, Modlin C, Beltran LC, Xu C, Su Z, Juneja P, Grigoryan G, Egelman EH, Conticello VP. Structural analysis of cross α-helical nanotubes provides insight into the designability of filamentous peptide nanomaterials. Nat Commun 2021; 12:407. [PMID: 33462223 PMCID: PMC7814010 DOI: 10.1038/s41467-020-20689-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 12/02/2020] [Indexed: 12/12/2022] Open
Abstract
The exquisite structure-function correlations observed in filamentous protein assemblies provide a paradigm for the design of synthetic peptide-based nanomaterials. However, the plasticity of quaternary structure in sequence-space and the lability of helical symmetry present significant challenges to the de novo design and structural analysis of such filaments. Here, we describe a rational approach to design self-assembling peptide nanotubes based on controlling lateral interactions between protofilaments having an unusual cross-α supramolecular architecture. Near-atomic resolution cryo-EM structural analysis of seven designed nanotubes provides insight into the designability of interfaces within these synthetic peptide assemblies and identifies a non-native structural interaction based on a pair of arginine residues. This arginine clasp motif can robustly mediate cohesive interactions between protofilaments within the cross-α nanotubes. The structure of the resultant assemblies can be controlled through the sequence and length of the peptide subunits, which generates synthetic peptide filaments of similar dimensions to flagella and pili.
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Affiliation(s)
- Fengbin Wang
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ordy Gnewou
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Charles Modlin
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Leticia C Beltran
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Chunfu Xu
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA
| | - Zhangli Su
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Puneet Juneja
- The Robert P. Apkarian Integrated Electron Microscopy Core (IEMC), Emory University, Atlanta, GA, 30322, USA
| | - Gevorg Grigoryan
- Department of Computer Science, Dartmouth College, Hanover, NH, 03755, USA.,Department of Biological Sciences, Dartmouth College, Hanover, NH, 03755, USA
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA, 22908, USA
| | - Vincent P Conticello
- Department of Chemistry, Emory University, Atlanta, GA, 30322, USA. .,The Robert P. Apkarian Integrated Electron Microscopy Core (IEMC), Emory University, Atlanta, GA, 30322, USA.
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50
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Hantke K. Compilation of Escherichia coli K-12 outer membrane phage receptors - their function and some historical remarks. FEMS Microbiol Lett 2021; 367:5721240. [PMID: 32009155 DOI: 10.1093/femsle/fnaa013] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/31/2020] [Indexed: 02/07/2023] Open
Abstract
Many Escherichia coli phages have been sequenced, but in most cases their sequences alone do not suffice to predict their host specificity. Analysis of phage resistant E. coli K-12 mutants have uncovered a certain set of outer membrane proteins and polysaccharides as receptors. In this review, a compilation of E. coli K12 phage receptors is provided and their functional characterization, often driven by studies on phage resistant mutants, is discussed in the historical context. While great progress has been made in this field thus far, several proteins in the outer membrane still await characterization as phage receptors.
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Affiliation(s)
- Klaus Hantke
- IMIT, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany
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