1
|
Krusenstjerna AC, Jusufovic N, Saylor TC, Stevenson B. DnaA modulates gene expression and morphologyof the Lyme Disease spirochete. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.08.598065. [PMID: 38895450 PMCID: PMC11185795 DOI: 10.1101/2024.06.08.598065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
All bacteria encode a multifunctional DNA-binding protein, DnaA, which initiates chromosomal replication. Despite having the most complex, segmented bacterial genome, little is known about Borrelia burgdorferi DnaA and its role in maintaining the spirochete's physiology. We utilized inducible CRISPR-interference and overexpression to modulate cellular levels of DnaA to better understand this essential protein. Dysregulation of DnaA, either up or down, significantly slowed replication and increased or decreased cell lengths. Using fluorescent microscopy, we found the DnaA CRISPRi mutants had increased numbers of chromosomes with irregular spacing patterns. The DnaA-depleted spirochetes also exhibited a significant defect in helical morphology. RNA-seq of the conditional mutants showed significant changes in the levels of transcripts involved with flagellar synthesis, elongation, cell division, virulence, and other functions. These findings demonstrate that the DnaA plays a commanding role in maintaining borrelial growth dynamics and protein expression, which are essential for the survival of the Lyme disease spirochete.
Collapse
Affiliation(s)
- Andrew C Krusenstjerna
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Nerina Jusufovic
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Timothy C Saylor
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
| | - Brian Stevenson
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky College of Medicine, Lexington, Kentucky, USA
- Department of Entomology, University of Kentucky, Lexington, Kentucky, USA
| |
Collapse
|
2
|
Potapova A, Garvey W, Dahl P, Guo S, Chang Y, Schwechheimer C, Trebino MA, Floyd KA, Phinney BS, Liu J, Malvankar NS, Yildiz FH. Outer membrane vesicles and the outer membrane protein OmpU govern Vibrio cholerae biofilm matrix assembly. mBio 2024; 15:e0330423. [PMID: 38206049 PMCID: PMC10865864 DOI: 10.1128/mbio.03304-23] [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: 12/07/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024] Open
Abstract
Biofilms are matrix-encased microbial communities that increase the environmental fitness and infectivity of many human pathogens including Vibrio cholerae. Biofilm matrix assembly is essential for biofilm formation and function. Known components of the V. cholerae biofilm matrix are the polysaccharide Vibrio polysaccharide (VPS), matrix proteins RbmA, RbmC, Bap1, and extracellular DNA, but the majority of the protein composition is uncharacterized. This study comprehensively analyzed the biofilm matrix proteome and revealed the presence of outer membrane proteins (OMPs). Outer membrane vesicles (OMVs) were also present in the V. cholerae biofilm matrix and were associated with OMPs and many biofilm matrix proteins suggesting that they participate in biofilm matrix assembly. Consistent with this, OMVs had the capability to alter biofilm structural properties depending on their composition. OmpU was the most prevalent OMP in the matrix, and its absence altered biofilm architecture by increasing VPS production. Single-cell force spectroscopy revealed that proteins critical for biofilm formation, OmpU, the matrix proteins RbmA, RbmC, Bap1, and VPS contribute to cell-surface adhesion forces at differing efficiency, with VPS showing the highest efficiency whereas Bap1 showing the lowest efficiency. Our findings provide new insights into the molecular mechanisms underlying biofilm matrix assembly in V. cholerae, which may provide new opportunities to develop inhibitors that specifically alter biofilm matrix properties and, thus, affect either the environmental survival or pathogenesis of V. cholerae.IMPORTANCECholera remains a major public health concern. Vibrio cholerae, the causative agent of cholera, forms biofilms, which are critical for its transmission, infectivity, and environmental persistence. While we know that the V. cholerae biofilm matrix contains exopolysaccharide, matrix proteins, and extracellular DNA, we do not have a comprehensive understanding of the majority of biofilm matrix components. Here, we discover outer membrane vesicles (OMVs) within the biofilm matrix of V. cholerae. Proteomic analysis of the matrix and matrix-associated OMVs showed that OMVs carry key matrix proteins and Vibrio polysaccharide (VPS) to help build biofilms. We also characterize the role of the highly abundant outer membrane protein OmpU in biofilm formation and show that it impacts biofilm architecture in a VPS-dependent manner. Understanding V. cholerae biofilm formation is important for developing a better prevention and treatment strategy framework.
Collapse
Affiliation(s)
- Anna Potapova
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - William Garvey
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Peter Dahl
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Shuaiqi Guo
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Yunjie Chang
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Carmen Schwechheimer
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Michael A. Trebino
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Kyle A. Floyd
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| | - Brett S. Phinney
- Proteomics Core Facility, UC Davis Genome Center, University of California-Davis, Davis, California, USA
| | - Jun Liu
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Nikhil S. Malvankar
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, West Haven, Connecticut, USA
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California-Santa Cruz, Santa Cruz, California, USA
| |
Collapse
|
3
|
Zamba-Campero M, Soliman D, Yu H, Lasseter AG, Chang YY, Liu J, Aravind L, Jewett MW, Storz G, Adams PP. Broadly conserved FlgV controls flagellar assembly and Borrelia burgdorferi dissemination in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.09.574855. [PMID: 38260563 PMCID: PMC10802407 DOI: 10.1101/2024.01.09.574855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Flagella propel pathogens through their environments yet are expensive to synthesize and are immunogenic. Thus, complex hierarchical regulatory networks control flagellar gene expression. Spirochetes are highly motile bacteria, but peculiarly in the Lyme spirochete Borrelia burgdorferi, the archetypal flagellar regulator σ28 is absent. We rediscovered gene bb0268 in B. burgdorferi as flgV, a broadly-conserved gene in the flagellar superoperon alongside σ28 in many Spirochaetes, Firmicutes and other phyla, with distant homologs in Epsilonproteobacteria. We found that B. burgdorferi FlgV is localized within flagellar motors. B. burgdorferi lacking flgV construct fewer and shorter flagellar filaments and are defective in cell division and motility. During the enzootic cycle, B. burgdorferi lacking flgV survive and replicate in Ixodes ticks but are attenuated for dissemination and infection in mice. Our work defines infection timepoints when spirochete motility is most crucial and implicates FlgV as a broadly distributed structural flagellar component that modulates flagellar assembly.
Collapse
Affiliation(s)
- Maxime Zamba-Campero
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel Soliman
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Huaxin Yu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Amanda G. Lasseter
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL, 32827, USA
| | - Yuen-Yan Chang
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06536, USA
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - L. Aravind
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
| | - Mollie W. Jewett
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL, 32827, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip P. Adams
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- Division of Immunity and Pathogenesis, Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL, 32827, USA
- Postdoctoral Research Associate Program, National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD 20892, USA
- Independent Research Scholar Program, Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| |
Collapse
|
4
|
Hansen T, Lee J, Reicher N, Ovadia G, Guo S, Guo W, Liu J, Braslavsky I, Rudich Y, Davies PL. Ice nucleation proteins self-assemble into large fibres to trigger freezing at near 0 °C. eLife 2023; 12:RP91976. [PMID: 38109272 PMCID: PMC10727499 DOI: 10.7554/elife.91976] [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: 12/20/2023] Open
Abstract
In nature, frost can form at a few degrees below 0 °C. However, this process requires the assembly of tens of thousands of ice-like water molecules that align together to initiate freezing at these relatively high temperatures. Water ordering on this scale is mediated by the ice nucleation proteins (INPs) of common environmental bacteria like Pseudomonas syringae and Pseudomonas borealis. However, individually, these 100 kDa proteins are too small to organize enough water molecules for frost formation, and it is not known how giant, megadalton-sized multimers, which are crucial for ice nucleation at high sub-zero temperatures, form. The ability of multimers to self-assemble was suggested when the transfer of an INP gene into Escherichia coli led to efficient ice nucleation. Here, we demonstrate that a positively charged subdomain at the C-terminal end of the central β-solenoid of the INP is crucial for multimerization. Truncation, relocation, or change of the charge of this subdomain caused a catastrophic loss of ice nucleation ability. Cryo-electron tomography of the recombinant E. coli showed that the INP multimers form fibres that are ~5 nm across and up to 200 nm long. A model of these fibres as an overlapping series of antiparallel dimers can account for all their known properties and suggests a route to making cell-free ice nucleators for biotechnological applications.
Collapse
Affiliation(s)
- Thomas Hansen
- Department of Biomedical and Molecular Sciences, Queen’s UniversityKingstonCanada
| | - Jocelyn Lee
- Department of Biomedical and Molecular Sciences, Queen’s UniversityKingstonCanada
| | - Naama Reicher
- Department of Earth and Planetary Sciences, The Weizmann Institute of ScienceRehovotIsrael
| | - Gil Ovadia
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science, and Nutrition, The Hebrew University of JerusalemRehovotIsrael
| | - Shuaiqi Guo
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Wangbiao Guo
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of MedicineNew HavenUnited States
| | - Ido Braslavsky
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science, and Nutrition, The Hebrew University of JerusalemRehovotIsrael
| | - Yinon Rudich
- Department of Earth and Planetary Sciences, The Weizmann Institute of ScienceRehovotIsrael
| | - Peter L Davies
- Department of Biomedical and Molecular Sciences, Queen’s UniversityKingstonCanada
| |
Collapse
|
5
|
Hansen T, Lee JC, Reicher N, Ovadia G, Guo S, Guo W, Liu J, Braslavsky I, Rudich Y, Davies PL. Ice nucleation proteins self-assemble into large fibres to trigger freezing at near 0 °C. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.03.551873. [PMID: 37577566 PMCID: PMC10418271 DOI: 10.1101/2023.08.03.551873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
In nature, frost can form at a few degrees below 0 °C. However, this process requires the assembly of tens of thousands of ice-like water molecules that align together to initiate freezing at these relatively high temperatures. Water ordering on this scale is mediated by the ice nucleation proteins of common environmental bacteria like Pseudomonas syringae and P. borealis. However, individually, these 100-kDa proteins are too small to organize enough water molecules for frost formation, and it is not known how giant, megadalton-sized multimers, which are crucial for ice nucleation at high sub-zero temperatures, form. The ability of multimers to self-assemble was suggested when the transfer of an ice nucleation protein gene into Escherichia coli led to efficient ice nucleation. Here we demonstrate that a positively-charged sub-domain at the C-terminal end of the central beta-solenoid of the ice nucleation protein is crucial for multimerization. Truncation, relocation, or change of the charge of this subdomain caused a catastrophic loss of ice nucleation ability. Cryo-electron tomography of the recombinant E. coli showed that the ice nucleation protein multimers form fibres that are ~ 5 nm across and up to 200 nm long. A model of these fibres as an overlapping series of antiparallel dimers can account for all their known properties and suggests a route to making cell-free ice nucleators for biotechnological applications.
Collapse
Affiliation(s)
- Thomas Hansen
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON Canada K7L 3N6
| | - Jocelyn C. Lee
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON Canada K7L 3N6
| | - Naama Reicher
- Department of Earth and Planetary Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gil Ovadia
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science, and Nutrition, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Shuaiqi Guo
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536
| | - Wangbiao Guo
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06536
| | - Ido Braslavsky
- The Robert H. Smith Faculty of Agriculture, Food and Environment, Institute of Biochemistry, Food Science, and Nutrition, The Hebrew University of Jerusalem, Rehovot 7610001, Israel
| | - Yinon Rudich
- Department of Earth and Planetary Sciences, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Peter L. Davies
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON Canada K7L 3N6
| |
Collapse
|
6
|
You Y, Ye F, Mao W, Yang H, Lai J, Deng S. An overview of the structure and function of the flagellar hook FlgE protein. World J Microbiol Biotechnol 2023; 39:126. [PMID: 36941455 DOI: 10.1007/s11274-023-03568-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 03/04/2023] [Indexed: 03/23/2023]
Abstract
The flagellum is an important organelle for the survival of bacteria and consists of a basal body, hook, and filament. The FlgE protein is the subunit of the hook that connects the basal body and the filament and determines the motility of bacteria. Also, flgE gene plays an essential role in flagellar biosynthesis, swimming ability and biofilm formation. Although the intact flagella and the major component filament have been extensively studied, so far, little is known about the comprehensive understanding of flagellar hook and FlgE. Here in this review, we summarize the structures of flagellar hook and its subunit FlgE in various species and physiological functions of FlgE, including the hook assembly, the structural characteristics of flagellar hook, the mechanical properties of hook, and the similarities and differences between FlgE (hook) and FlgG (distal rod), with special attention on the interaction of FlgE with other molecules, the antigenicity and pro-inflammatory effect of FlgE, and cross-linking of FlgE in spirochetes. We hope our summary of this review could provide a better understanding of the FlgE protein and provide some useful information for developing new effective antibacterial drugs in the future work.
Collapse
Affiliation(s)
- Yu You
- Biopharmaceutical Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China.
| | - Fei Ye
- Department of Laboratory Medicine, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Wei Mao
- Biopharmaceutical Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Hong Yang
- Biopharmaceutical Research Institute, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Jijia Lai
- Department of Laboratory Medicine, Hospital of Chengdu Office of People's Government of Tibetan Autonomous Region, Chengdu, 610041, China
| | - Shun Deng
- Sichuan Province Orthopedic Hospital, 132 West First Section First Ring Road, Chengdu, 610041, China
| |
Collapse
|
7
|
Diving into the complexity of the spirochetal endoflagellum. Trends Microbiol 2023; 31:294-307. [PMID: 36244923 DOI: 10.1016/j.tim.2022.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/27/2022]
Abstract
Spirochaetes, a phylum that includes medically important pathogens such as the causative agents of Lyme disease, syphilis, and leptospirosis, are in many ways highly unique bacteria. Their cell morphology, subcellular organization, and metabolism reveal atypical features. Spirochetal motility is also singular, dependent on the presence of periplasmic flagella or endoflagella, inserted subterminally at cell poles and not penetrating the outer membrane and elongating outside the cell as in enterobacteria. In this review we present a comprehensive comparative genomics analysis of endoflagellar systems in spirochetes, highlighting recent findings on the flagellar basal body and filament. Continued progress in understanding the function and architecture of spirochetal flagella is uncovering paradigm-shifting mechanisms of bacterial motility.
Collapse
|
8
|
Kurniyati K, Chang Y, Guo W, Liu J, Malkowski MG, Li C. Anti-σ 28 Factor FlgM Regulates Flagellin Gene Expression and Flagellar Polarity of Treponema denticola. J Bacteriol 2023; 205:e0046322. [PMID: 36715541 PMCID: PMC9945498 DOI: 10.1128/jb.00463-22] [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] [Received: 12/02/2022] [Accepted: 01/07/2023] [Indexed: 01/31/2023] Open
Abstract
FlgM, an antagonist of FliA (also known as σ28), inhibits transcription of bacterial class 3 flagellar genes. It does so primarily through binding to free σ28 to prevent it from forming a complex with core RNA polymerase. We recently identified an FliA homolog (FliATd) in the oral spirochete Treponema denticola; however, its antagonist FlgM remained uncharacterized. Herein, we provide several lines of evidence that TDE0201 functions as an antagonist of FliATd. TDE0201 is structurally similar to FlgM proteins, although its sequence is not conserved. Heterologous expression of TDE0201 in Escherichia coli inhibits its flagellin gene expression and motility. Biochemical and mutational analyses demonstrate that TDE0201 binds to FliATd and prevents it from binding to the σ28-dependent promoter. Deletions of flgM genes typically enhance bacterial class 3 flagellar gene expression; however, deletion of TDE0201 has an opposite effect (e.g., the mutant has a reduced level of flagellins). Follow-up studies revealed that deletion of TDE0201 leads to FliATd turnover, which in turn impairs the expression of flagellin genes. Swimming plate, cell tracking, and cryo-electron tomography analyses further disclosed that deletion of TDE0201 impairs spirochete motility and alters flagellar number and polarity: i.e., instead of having bipolar flagella, the mutant has flagella only at one end of cells. Collectively, these results indicate that TDE0201 is a FlgM homolog but acts differently from its counterparts in other bacteria. IMPORTANCE Spirochetes are a group of bacteria that cause several human diseases. A unique aspect of spirochetes is that they have bipolar periplasmic flagella (PFs), which bestow on the spirochetes a unique spiral shape and distinct swimming behaviors. While the structure and function of PFs have been extensively studied in spirochetes, the molecular mechanism that regulates the PFs' morphogenesis and assembly is poorly understood. In this report, FlgM, an anti-σ28 factor, is identified and functionally characterized in the oral spirochete Treponema denticola. Our results show that FlgM regulates the number and polarity of PFs via a unique mechanism. Identification of FliA and FlgM in T. denticola sets a benchmark to investigate their roles in other spirochetes.
Collapse
Affiliation(s)
- Kurni Kurniyati
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Yunjie Chang
- Department of Microbial Pathogenesis, Yale University, School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, School of Medicine, New Haven, Connecticut, USA
| | - Wangbiao Guo
- Department of Microbial Pathogenesis, Yale University, School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, School of Medicine, New Haven, Connecticut, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University, School of Medicine, New Haven, Connecticut, USA
- Microbial Sciences Institute, Yale University, School of Medicine, New Haven, Connecticut, USA
| | - Michael G. Malkowski
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, Buffalo, New York, USA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, USA
- Department of Microbiology and Immunology, Virginia Commonwealth University, Richmond, Virginia, USA
| |
Collapse
|
9
|
Identification and Characterization of the Alternative σ 28 Factor in Treponema denticola. J Bacteriol 2022; 204:e0024822. [PMID: 36043861 PMCID: PMC9487585 DOI: 10.1128/jb.00248-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
FliA (also known as σ28), a member of the bacterial σ70 family of transcription factors, directs RNA polymerase to flagellar late (class 3) promoters and initiates transcription. FliA has been studied in several bacteria, yet its role in spirochetes has not been established. In this report, we identify and functionally characterize a FliA homolog (TDE2683) in the oral spirochete Treponema denticola. Computational, genetic, and biochemical analyses demonstrated that TDE2683 has a structure similar to that of the σ28 of Escherichia coli, binds to σ28-dependent promoters, and can functionally replace the σ28 of E. coli. However, unlike its counterparts from other bacteria, TDE2683 cannot be deleted, suggesting its essential role in the survival of T. denticola. In vitro site-directed mutagenesis revealed that E221 and V231, two conserved residues in the σ4 region of σ28, are indispensable for the binding activity of TDE2683 to the σ28-dependent promoter. We then mutated these two residues in T. denticola and found that the mutations impair the expression of flagellin and chemotaxis genes and bacterial motility as well. Cryo-electron tomography analysis further revealed that the mutations disrupt the flagellar symmetry (i.e., number and placement) of T. denticola. Collectively, these results indicate that TDE2683 is a σ28 transcription factor that regulates the class 3 gene expression and controls the flagellar symmetry of T. denticola. To the best of our knowledge, this is the first report establishing the functionality of FliA in spirochetes. IMPORTANCE Spirochetes are a group of medically important but understudied bacteria. One of the unique aspects of spirochetes is that they have periplasmic flagella (PF, also known as endoflagella) which give rise to their unique spiral shape and distinct swimming behaviors and play a critical role in the pathophysiology of spirochetes. PF are structurally similar to external flagella, but the underpinning mechanism that regulates PF biosynthesis and assembly remains largely unknown. By using the oral spirochete Treponema denticola as a model, this report provides several lines of evidence that FliA, a σ28 transcriptional factor, regulates the late flagellin gene (class 3) expression, PF assembly, and flagellar symmetry as well, which provides insights into flagellar regulation and opens an avenue to investigate the role of σ28 in spirochetes.
Collapse
|
10
|
Exploitation of a Bacterium-Encoded Lytic Transglycosylase by a Human Oral Lytic Phage To Facilitate Infection. J Virol 2022; 96:e0106322. [PMID: 36000841 PMCID: PMC9472602 DOI: 10.1128/jvi.01063-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Bacteriophages (phages) are an integral part of the human oral microbiome. Their roles in modulating bacterial physiology and shaping microbial communities have been discussed but remain understudied due to limited isolation and characterization of oral phage. Here, we report the isolation of LC001, a lytic phage targeting human oral Schaalia odontolytica (formerly known as Actinomyces odontolyticus) strain XH001. We showed that LC001 attached to and infected surface-grown, but not planktonic, XH001 cells, and it displayed remarkable host specificity at the strain level. Whole-genome sequencing of spontaneous LC001-resistant, surface-grown XH001 mutants revealed that the majority of the mutants carry nonsense or frameshift mutations in XH001 gene APY09_05145 (renamed ltg-1), which encodes a putative lytic transglycosylase (LT). The mutants are defective in LC001 binding, as revealed by direct visualization of the significantly reduced attachment of phage particles to the XH001 spontaneous mutants compared that to the wild type. Meanwhile, targeted deletion of ltg-1 produced a mutant that is defective in LC001 binding and resistant to LC001 infection even as surface-grown cells, while complementation of ltg-1 in the mutant background restored the LC001-sensitive phenotype. Intriguingly, similar expression levels of ltg-1 were observed in surface-grown and planktonic XH001, which displayed LC001-binding and nonbinding phenotypes, respectively. Furthermore, the overexpression of ltg-1 failed to confer an LC001-binding and -sensitive phenotype to planktonic XH001. Thus, our data suggested that rather than directly serving as a phage receptor, ltg-1-encoded LT may increase the accessibility of phage receptor, possibly via its enzymatic activity, by cleaving the peptidoglycan structure for better receptor exposure during peptidoglycan remodeling, a function that can be exploited by LC001 to facilitate infection. IMPORTANCE The evidence for the presence of a diverse and abundant phage population in the host-associated oral microbiome came largely from metagenomic analysis or the observation of virus-like particles within saliva/plaque samples, while the isolation of oral phage and investigation of their interaction with bacterial hosts are limited. Here, we report the isolation of LC001, the first lytic phage targeting oral Schaalia odontolytica. Our study suggested that LC001 may exploit the host bacterium-encoded lytic transglycosylase function to gain access to the receptor, thus facilitating its infection.
Collapse
|
11
|
Kurniyati K, Chang Y, Liu J, Li C. Transcriptional and functional characterizations of multiple flagellin genes in spirochetes. Mol Microbiol 2022; 118:175-190. [PMID: 35776658 PMCID: PMC9481697 DOI: 10.1111/mmi.14959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/28/2022]
Abstract
The flagellar filament is a helical propeller for bacterial locomotion. In external flagellates, the filaments are mostly homopolymers of a single flagellin protein. By contrast, the flagellar filaments of spirochetes are mostly heteropolymers of multiple flagellin proteins. This report seeks to investigate the role of multiple flagellin proteins using the oral spirochete Treponema denticola as a model. First, biochemical and genetic studies uncover that the flagellar filaments of T. denticola mainly comprise four proteins, FlaA, FlaB1, FlaB2, and FlaB3, in a defined stoichiometry. Second, transcriptional analyses reveal that the genes encoding these four proteins are regulated by two different transcriptional factors, sigma28 and sigma70 . Third, loss-of-function studies demonstrate that each individual flagellin protein contributes to spirochete motility, but none of them is absolutely required. Last, we provide genetic and structural evidence that FlaA forms a "seam"-like structure around the core and that deletion of individual flagellin protein alters the flagellar homeostasis. Collectively, these results demonstrate that T. denticola has evolved a unique mechanism to finely regulate its flagellar filament gene expression and assembly which renders the organelle with the right number, shape, strength, and structure for its distinct motility.
Collapse
Affiliation(s)
- Kurni Kurniyati
- Department of Oral Craniofacial Molecular Biology, School of DentistryVirginia Commonwealth UniversityRichmondVirginiaUSA
| | - Yunjie Chang
- Microbial Sciences InstituteYale UniversityWest HavenConnecticutUSA
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Jun Liu
- Microbial Sciences InstituteYale UniversityWest HavenConnecticutUSA
- Department of Microbial PathogenesisYale School of MedicineNew HavenConnecticutUSA
| | - Chunhao Li
- Department of Oral Craniofacial Molecular Biology, School of DentistryVirginia Commonwealth UniversityRichmondVirginiaUSA
- Department of Microbiology and Immunology, School of MedicineVirginia Commonwealth UniversityRichmondVirginiaUSA
| |
Collapse
|
12
|
Yoshinari NH, Bonoldi VLN, Bonin S, Falkingham E, Trevisan G. The Current State of Knowledge on Baggio–Yoshinari Syndrome (Brazilian Lyme Disease-like Illness): Chronological Presentation of Historical and Scientific Events Observed over the Last 30 Years. Pathogens 2022; 11:pathogens11080889. [PMID: 36015013 PMCID: PMC9415174 DOI: 10.3390/pathogens11080889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/01/2022] [Accepted: 08/03/2022] [Indexed: 11/22/2022] Open
Abstract
Baggio–Yoshinari Syndrome (BYS) is an emerging Brazilian tick-borne infectious disease that clinically mimics Lyme Disease (LD) present in the Northern Hemisphere. LD is caused by spirochetes belonging to the Borrelia burgdorferi sensu lato complex and transmitted by Ixodid ticks of complex Ixodes rticinus. On the contrary, BYS is transmitted by hard Ixodid ticks of the genera Amblyomma, Rhipicephalus and Dermacentor. In 1992, the first cases of BYS were described in patients that developed EM rash, flu-like symptoms and arthritis after tick bite episodes. Since these findings, research in BYS has been developing for more than 30 years and shows that its epidemiological, clinical and laboratorial features are different from LD. Borrelia burgdorferi was never isolated in Brazil. In addition, specific serologic tests have shown little positivity. Furthermore, peripheral blood analysis of patients using electron microscopy exhibited structures resembling spirochete-like microorganisms or the latent forms of spirochetes (L form or cell wall deficient bacteria). For these reasons, Brazilian zoonosis was defined as an exotic and emerging Brazilian infectious disease, transmitted by ticks not belonging to the Ixodes ricinus complex, caused by latent spirochetes belonging to the B. burgdorferi sensu lato complex with atypical morphology. The Brazilian ecosystem, combined with its ticks and reservoir biodiversity, possibly contributed to the origin of this new zoonosis, which emerged as a result of the passage of B. burgdorferi through exotic vectors and reservoirs.
Collapse
Affiliation(s)
- Natalino Hajime Yoshinari
- Reumatologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo 05508-220, Brazil
| | - Virginia Lucia Nazario Bonoldi
- Reumatologia, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo 05508-220, Brazil
| | - Serena Bonin
- DSM—Department of Medical Sciences, University of Trieste, 34149 Trieste, Italy
- Correspondence: ; Tel.: +39-040-3993266
| | - Erica Falkingham
- DSM—Department of Medical Sciences, University of Trieste, 34149 Trieste, Italy
| | - Giusto Trevisan
- DSM—Department of Medical Sciences, University of Trieste, 34149 Trieste, Italy
| |
Collapse
|
13
|
Identification of Genes Required for Swarming Motility in Bacillus subtilis Using Transposon Mutagenesis and High-Throughput Sequencing (TnSeq). J Bacteriol 2022; 204:e0008922. [PMID: 35638827 DOI: 10.1128/jb.00089-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis exhibits swarming motility, a flagellar-mediated form of surface motility. Here, we use transposon mutagenesis and sequencing (TnSeq) to perform a high-throughput screen for candidate genes required for swarming. The TnSeq approach identified all of the known genes required for flagellar biosynthesis and nearly all of the previously reported regulators that promote swarming. Moreover, we identified an additional 36 genes that improve swarming and validated them individually. Among these, two mutants with severe defects were recovered, including fliT, required for flagellar biosynthesis, and a gene of unknown function, yolB, whose defect could not be attributed to a lack of flagella. In addition to discovering additional genes required for B. subtilis swarming, our work validates TnSeq as a powerful approach for comprehensively identifying genes important for nonessential processes such as colony expansion on plates. IMPORTANCE In TnSeq, transposons are randomly inserted throughout the chromosome at a population level, but insertions that disrupt genes of essential function cause strains that carry them to fall out of the population and appear underrepresented at the sequence level. Here, we apply TnSeq to the nonessential phenotype of motility in B. subtilis and spatially select for cells proficient in swarming. We find that insertions in nearly all genes previously identified as required for swarming are underrepresented in TnSeq analysis, and we identify 36 additional genes that enhance swarming. We demonstrate that TnSeq is a powerful tool for the genetic analysis of motility and likely other nonlethal screens for which enrichment is strong.
Collapse
|
14
|
Kaplan M, Oikonomou CM, Wood CR, Chreifi G, Subramanian P, Ortega DR, Chang Y, Beeby M, Shaffer CL, Jensen GJ. Novel transient cytoplasmic rings stabilize assembling bacterial flagellar motors. EMBO J 2022; 41:e109523. [PMID: 35301732 PMCID: PMC9108667 DOI: 10.15252/embj.2021109523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 01/31/2022] [Accepted: 02/16/2022] [Indexed: 12/20/2022] Open
Abstract
The process by which bacterial cells build their intricate flagellar motility apparatuses has long fascinated scientists. Our understanding of this process comes mainly from studies of purified flagella from two species, Escherichia coli and Salmonella enterica. Here, we used electron cryo-tomography (cryo-ET) to image the assembly of the flagellar motor in situ in diverse Proteobacteria: Hylemonella gracilis, Helicobacter pylori, Campylobacter jejuni, Pseudomonas aeruginosa, Pseudomonas fluorescens, and Shewanella oneidensis. Our results reveal the in situ structures of flagellar intermediates, beginning with the earliest flagellar type III secretion system core complex (fT3SScc) and MS-ring. In high-torque motors of Beta-, Gamma-, and Epsilon-proteobacteria, we discovered novel cytoplasmic rings that interact with the cytoplasmic torque ring formed by FliG. These rings, associated with the MS-ring, assemble very early and persist until the stators are recruited into their periplasmic ring; in their absence the stator ring does not assemble. By imaging mutants in Helicobacter pylori, we found that the fT3SScc proteins FliO and FliQ are required for the assembly of these novel cytoplasmic rings. Our results show that rather than a simple accretion of components, flagellar motor assembly is a dynamic process in which accessory components interact transiently to assist in building the complex nanomachine.
Collapse
Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Catherine M Oikonomou
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Cecily R Wood
- Department of Veterinary ScienceUniversity of KentuckyLexingtonKYUSA
| | - Georges Chreifi
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Poorna Subramanian
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Davi R Ortega
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Yi‐Wei Chang
- Department of Biochemistry and BiophysicsPerelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Morgan Beeby
- Department of Life SciencesImperial College LondonLondonUK
| | - Carrie L Shaffer
- Department of Veterinary ScienceUniversity of KentuckyLexingtonKYUSA
- Department of Microbiology, Immunology, and Molecular GeneticsUniversity of KentuckyLexingtonKYUSA
- Department of Pharmaceutical SciencesUniversity of KentuckyLexingtonKYUSA
| | - Grant J Jensen
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
- Department of Chemistry and BiochemistryBrigham Young UniversityProvoUTUSA
| |
Collapse
|
15
|
Rieu M, Krutyholowa R, Taylor NMI, Berry RM. A new class of biological ion-driven rotary molecular motors with 5:2 symmetry. Front Microbiol 2022; 13:948383. [PMID: 35992645 PMCID: PMC9389320 DOI: 10.3389/fmicb.2022.948383] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/04/2022] [Indexed: 11/15/2022] Open
Abstract
Several new structures of three types of protein complexes, obtained by cryo-electron microscopy (cryo-EM) and published between 2019 and 2021, identify a new family of natural molecular wheels, the "5:2 rotary motors." These span the cytoplasmic membranes of bacteria, and their rotation is driven by ion flow into the cell. They consist of a pentameric wheel encircling a dimeric axle within the cytoplasmic membrane of both Gram-positive and gram-negative bacteria. The axles extend into the periplasm, and the wheels extend into the cytoplasm. Rotation of these wheels has never been observed directly; it is inferred from the symmetry of the complexes and from the roles they play within the larger systems that they are known to power. In particular, the new structure of the stator complex of the Bacterial Flagellar Motor, MotA5B2, is consistent with a "wheels within wheels" model of the motor. Other 5:2 rotary motors are believed to share the core rotary function and mechanism, driven by ion-motive force at the cytoplasmic membrane. Their structures diverge in their periplasmic and cytoplasmic parts, reflecting the variety of roles that they perform. This review focuses on the structures of 5:2 rotary motors and their proposed mechanisms and functions. We also discuss molecular rotation in general and its relation to the rotational symmetry of molecular complexes.
Collapse
Affiliation(s)
- Martin Rieu
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
| | - Roscislaw Krutyholowa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nicholas M. I. Taylor
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
- Nicholas M. I. Taylor,
| | - Richard M. Berry
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
- *Correspondence: Richard M. Berry,
| |
Collapse
|
16
|
Fule L, Halifa R, Fontana C, Sismeiro O, Legendre R, Varet H, Coppée JY, Murray GL, Adler B, Hendrixson DR, Buschiazzo A, Guo S, Liu J, Picardeau M. Role of the major determinant of polar flagellation FlhG in the endoflagella-containing spirochete Leptospira. Mol Microbiol 2021; 116:1392-1406. [PMID: 34657338 DOI: 10.1111/mmi.14831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/06/2021] [Accepted: 10/13/2021] [Indexed: 01/31/2023]
Abstract
Spirochetes can be distinguished from other bacteria by their spiral-shaped morphology and subpolar periplasmic flagella. This study focused on FlhF and FlhG, which control the spatial and numerical regulation of flagella in many exoflagellated bacteria, in the spirochete Leptospira. In contrast to flhF which seems to be essential in Leptospira, we demonstrated that flhG- mutants in both the saprophyte L. biflexa and the pathogen L. interrogans were less motile than the wild-type strains in gel-like environments but not hyperflagellated as reported previously in other bacteria. Cryo-electron tomography revealed that the distance between the flagellar basal body and the tip of the cell decreased significantly in the flhG- mutant in comparison to wild-type and complemented strains. Additionally, comparative transcriptome analyses of L. biflexa flhG- and wild-type strains showed that FlhG acts as a negative regulator of transcription of some flagellar genes. We found that the L. interrogans flhG- mutant was attenuated for virulence in the hamster model. Cross-species complementation also showed that flhG is not interchangeable between species. Our results indicate that FlhF and FlhG in Leptospira contribute to governing cell motility but our data support the hypothesis that FlhF and FlhG function differently in each bacterial species, including among spirochetes.
Collapse
Affiliation(s)
- Lenka Fule
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
- Université de Paris, Paris, France
| | - Ruben Halifa
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
| | - Celia Fontana
- Boehringer Ingelheim Santé Animale, Saint Priest, France
| | - Odile Sismeiro
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
| | - Rachel Legendre
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Hugo Varet
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
- Bioinformatics and Biostatistics Hub, Department of Computational Biology, Institut Pasteur, Paris, France
| | - Jean-Yves Coppée
- Transcriptome and Epigenome Platform, Biomics, Center for Technological Resources and Research (C2RT), Institut Pasteur, Paris, France
| | - Gerald L Murray
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Ben Adler
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David R Hendrixson
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Alejandro Buschiazzo
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
- Laboratory of Molecular and Structural Microbiology, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Shuaiqi Guo
- Microbial Sciences Institute & Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Jun Liu
- Microbial Sciences Institute & Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, Connecticut, USA
| | - Mathieu Picardeau
- Institut Pasteur, Biology of Spirochetes Unit, Paris, France
- Pasteur International Unit, Integrative Microbiology of Zoonotic Agents, Institut Pasteur de Montevideo, Montevideo, Uruguay/Institut Pasteur, Paris, France
| |
Collapse
|
17
|
Abstract
The FliE component of the bacterial flagellum is the first protein secreted through the flagellar type III secretion system (fT3SS) that is capable of self-assembly into the growing bacterial organelle. The FliE protein plays dual roles in the assembly of the Salmonella flagellum as the final component of the flagellar type III secretion system (fT3SS) and as an adaptor protein that anchors the rod (drive shaft) of the flagellar motor to the membrane-imbedded MS-ring structure. This work has identified the interactions between FliE and other proteins at the inner membrane base of the flagellar machine. The fliE sequence coding for the 104-amino-acid protein was subject to saturating mutagenesis. Single-amino-acid substitutions were generated in fliE, resulting in motility phenotypes. From these mutants, intergenic suppressor mutations were generated, isolated, and characterized. Single-amino-acid mutations defective in FliE function were localized to the N- and C-terminal helices of the protein. Motile suppressors of amino acid mutations in fliE were found in rod protein genes flgB and flgC, the MS ring gene, fliF, and one of the core T3SS genes, fliR. These results support the hypothesis that FliE acts as a linker protein consisting of an N-terminal α-helix that is involved in the interaction with the MS ring with a rotational symmetry and a C-terminal coiled coil that interacts with FliF, FliR, FlgB, and FlgC, and these interactions open the exit gate of the protein export channel of the fT3SS.
Collapse
|
18
|
Xu H, Hu B, Flesher DA, Liu J, Motaleb MA. BB0259 Encompasses a Peptidoglycan Lytic Enzyme Function for Proper Assembly of Periplasmic Flagella in Borrelia burgdorferi. Front Microbiol 2021; 12:692707. [PMID: 34659138 PMCID: PMC8517470 DOI: 10.3389/fmicb.2021.692707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/19/2021] [Indexed: 11/18/2022] Open
Abstract
Assembly of the bacterial flagellar rod, hook, and filament requires penetration through the peptidoglycan (PG) sacculus and outer membrane. In most β- and γ-proteobacteria, the protein FlgJ has two functional domains that enable PG hydrolyzing activity to create pores, facilitating proper assembly of the flagellar rod. However, two distinct proteins performing the same functions as the dual-domain FlgJ are proposed in δ- and ε-proteobacteria as well as spirochetes. The Lyme disease spirochete Borrelia burgdorferi genome possesses a FlgJ and a PG lytic SLT enzyme protein homolog (BB0259). FlgJ in B. burgdorferi is crucial for flagellar hook and filament assembly but not for the proper rod assembly reported in other bacteria. However, BB0259 has never been characterized. Here, we use cryo-electron tomography to visualize periplasmic flagella in different bb0259 mutant strains and provide evidence that the E580 residue of BB0259 is essential for PG-hydrolyzing activity. Without the enzyme activity, the flagellar hook fails to penetrate through the pores in the cell wall to complete assembly of an intact periplasmic flagellum. Given that FlgJ and BB0259 interact with each other, they likely coordinate the penetration through the PG sacculus and assembly of a functional flagellum in B. burgdorferi and other spirochetes. Because of its role, we renamed BB0259 as flagellar-specific lytic transglycosylase or LTaseBb.
Collapse
Affiliation(s)
- Hui Xu
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| | - Bo Hu
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - David A. Flesher
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT, United States
- Microbial Sciences Institute, Yale University, West Haven, CT, United States
| | - Md A. Motaleb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, United States
| |
Collapse
|
19
|
A simple method to detect Borrelia burgdorferi sensu lato proteins in different sub-cellular compartments by immunofluorescence. Ticks Tick Borne Dis 2021; 12:101808. [PMID: 34455142 DOI: 10.1016/j.ttbdis.2021.101808] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 07/20/2021] [Accepted: 07/28/2021] [Indexed: 01/15/2023]
Abstract
Spirochaetes constitute a unique phylum of bacteria, many of which cause severe clinical diseases. Borrelia burgdorferi sensu lato (B. burgdorferi s.l.)-the primary agent of Lyme borreliosis (LB)-is a quintessential member of this poorly understood phylum and the leading cause of tick-borne illness throughout most of the northern hemisphere. Despite its importance in human health, we lack a fundamental understanding of how B. burgdorferi s.l. is able to accomplish basic physiological tasks, such as DNA replication/segregation, and cell elongation or division. Recent advances in molecular tools to probe these essential cellular processes are great strides forward but require genetic manipulation. The latter is important since not all agents of LB are genetically tractable. Here, we describe a single method that is capable of fluorescently labeling B. burgdorferi s.l. proteins in different sub-cellular compartments. A comparative analysis of six different methods indicates that our optimized procedure outperforms all others and is the first to localize a cytoplasmic protein in B. burgdorferi s.l. by immunofluorescence. We contend that this strategy could be easily adapted to study the localization of any protein, in many Borrelia genospecies, information that will yield functional insights into the complex biology of this fascinating group of bacteria. In addition, it may provide new avenues of research in both in situ studies and in Lyme diagnostics.
Collapse
|
20
|
Xiang Y, Surovtsev IV, Chang Y, Govers SK, Parry BR, Liu J, Jacobs-Wagner C. Interconnecting solvent quality, transcription, and chromosome folding in Escherichia coli. Cell 2021; 184:3626-3642.e14. [PMID: 34186018 DOI: 10.1016/j.cell.2021.05.037] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 12/09/2020] [Accepted: 05/25/2021] [Indexed: 12/12/2022]
Abstract
All cells fold their genomes, including bacterial cells, where the chromosome is compacted into a domain-organized meshwork called the nucleoid. How compaction and domain organization arise is not fully understood. Here, we describe a method to estimate the average mesh size of the nucleoid in Escherichia coli. Using nucleoid mesh size and DNA concentration estimates, we find that the cytoplasm behaves as a poor solvent for the chromosome when the cell is considered as a simple semidilute polymer solution. Monte Carlo simulations suggest that a poor solvent leads to chromosome compaction and DNA density heterogeneity (i.e., domain formation) at physiological DNA concentration. Fluorescence microscopy reveals that the heterogeneous DNA density negatively correlates with ribosome density within the nucleoid, consistent with cryoelectron tomography data. Drug experiments, together with past observations, suggest the hypothesis that RNAs contribute to the poor solvent effects, connecting chromosome compaction and domain formation to transcription and intracellular organization.
Collapse
Affiliation(s)
- Yingjie Xiang
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520, USA; Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA
| | - Ivan V Surovtsev
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Yunjie Chang
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Sander K Govers
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA; Department of Biology and Institute of Chemistry, Engineering and Medicine for Human Health, Stanford University, Palo Alto, CA 94305, USA
| | - Bradley R Parry
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA
| | - Jun Liu
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA
| | - Christine Jacobs-Wagner
- Microbial Sciences Institute, Yale University, West Haven, CT 06516, USA; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520, USA; Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA; Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT 06510, USA; Department of Biology and Institute of Chemistry, Engineering and Medicine for Human Health, Stanford University, Palo Alto, CA 94305, USA.
| |
Collapse
|
21
|
CwlQ Is Required for Swarming Motility but Not Flagellar Assembly in Bacillus subtilis. J Bacteriol 2021; 203:JB.00029-21. [PMID: 33649146 DOI: 10.1128/jb.00029-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/22/2021] [Indexed: 11/20/2022] Open
Abstract
Lytic enzymes play an essential role in the remodeling of bacterial peptidoglycan (PG), an extracellular mesh-like structure that retains the membrane in the context of high internal osmotic pressure. Peptidoglycan must be unfailingly stable to preserve cell integrity, but must also be dynamically remodeled for the cell to grow, divide, and insert macromolecular machines. The flagellum is one such macromolecular machine that transits the PG, and flagellar insertion is aided by localized activity of a dedicated PG lyase in Gram-negative bacteria. To date, there is no known dedicated lyase in Gram-positive bacteria for the insertion of flagella. Here, we take a reverse-genetic candidate-gene approach and find that cells mutated for the lytic transglycosylase CwlQ exhibit a severe defect in flagellum-dependent swarming motility. We further show that CwlQ is expressed by the motility sigma factor SigD and is secreted by the type III secretion system housed inside the flagellum. Nonetheless, cells with mutations of CwlQ remain proficient for flagellar biosynthesis even when mutated in combination with four other lyases related to motility (LytC, LytD, LytF, and CwlO). The PG lyase (or lyases) essential for flagellar synthesis in B. subtilis, if any, remains unknown.IMPORTANCE Bacteria are surrounded by a wall of peptidoglycan and early work in Bacillus subtilis was the first to suggest that bacteria needed to enzymatically remodel the wall to permit insertion of the flagellum. No PG remodeling enzyme alone or in combination, however, has been found to be essential for flagellar assembly in B. subtilis Here, we take a reverse-genetic candidate-gene approach and find that the PG lytic transglycosylase CwlQ is required for swarming motility. Subsequent characterization determined that while CwlQ was coexpressed with motility genes and is secreted by the flagellar secretion apparatus, it was not required for flagellar synthesis. The PG lyase needed for flagellar assembly in B. subtilis remains unknown.
Collapse
|
22
|
Tan J, Zhang X, Wang X, Xu C, Chang S, Wu H, Wang T, Liang H, Gao H, Zhou Y, Zhu Y. Structural basis of assembly and torque transmission of the bacterial flagellar motor. Cell 2021; 184:2665-2679.e19. [PMID: 33882274 DOI: 10.1016/j.cell.2021.03.057] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/28/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022]
Abstract
The bacterial flagellar motor is a supramolecular protein machine that drives rotation of the flagellum for motility, which is essential for bacterial survival in different environments and a key determinant of pathogenicity. The detailed structure of the flagellar motor remains unknown. Here we present an atomic-resolution cryoelectron microscopy (cryo-EM) structure of the bacterial flagellar motor complexed with the hook, consisting of 175 subunits with a molecular mass of approximately 6.3 MDa. The structure reveals that 10 peptides protruding from the MS ring with the FlgB and FliE subunits mediate torque transmission from the MS ring to the rod and overcome the symmetry mismatch between the rotational and helical structures in the motor. The LP ring contacts the distal rod and applies electrostatic forces to support its rotation and torque transmission to the hook. This work provides detailed molecular insights into the structure, assembly, and torque transmission mechanisms of the flagellar motor.
Collapse
Affiliation(s)
- Jiaxing Tan
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; The MOE Key Laboratory for Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xing Zhang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang 310058, China; Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, Zhejiang 311121, China.
| | - Xiaofei Wang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; The MOE Key Laboratory for Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Caihuang Xu
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Shenghai Chang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hangjun Wu
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ting Wang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; The MOE Key Laboratory for Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Huihui Liang
- Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Haichun Gao
- Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yan Zhou
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; The MOE Key Laboratory for Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yongqun Zhu
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Life Sciences Institute and School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; The MOE Key Laboratory for Biosystems Homeostasis & Protection and Zhejiang Provincial Key Laboratory of Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China; The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China; Institute of Microbiology, Zhejiang University, Hangzhou, Zhejiang 310058, China; Cancer Center, Zhejiang University, Hangzhou, Zhejiang 310058, China.
| |
Collapse
|
23
|
Kaplan M, Nicolas WJ, Zhao W, Carter SD, Metskas LA, Chreifi G, Ghosal D, Jensen GJ. In Situ Imaging and Structure Determination of Biomolecular Complexes Using Electron Cryo-Tomography. Methods Mol Biol 2021; 2215:83-111. [PMID: 33368000 DOI: 10.1007/978-1-0716-0966-8_4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Electron cryo-tomography (cryo-ET) is a technique that allows the investigation of intact macromolecular complexes while they are in their cellular milieu. Over the years, cryo-ET has had a huge impact on our understanding of how large biomolecular complexes look like, how they assemble, disassemble, function, and evolve(d). Recent hardware and software developments and combining cryo-ET with other techniques, e.g., focused ion beam milling (FIB-milling) and cryo-light microscopy, has extended the realm of cryo-ET to include transient molecular complexes embedded deep in thick samples (like eukaryotic cells) and enhanced the resolution of structures obtained by cryo-ET. In this chapter, we will present an outline of how to perform cryo-ET studies on a wide variety of biological samples including prokaryotic and eukaryotic cells and biological plant tissues. This outline will include sample preparation, data collection, and data processing as well as hybrid approaches like FIB-milling, cryosectioning, and cryo-correlated light and electron microscopy (cryo-CLEM).
Collapse
Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - William J Nicolas
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Wei Zhao
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Stephen D Carter
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Lauren Ann Metskas
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA
| | - Georges Chreifi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Department of Biochemistry and Molecular Biology; and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, USA.
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
| |
Collapse
|
24
|
Structural Conservation and Adaptation of the Bacterial Flagella Motor. Biomolecules 2020; 10:biom10111492. [PMID: 33138111 PMCID: PMC7693769 DOI: 10.3390/biom10111492] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 10/26/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023] Open
Abstract
Many bacteria require flagella for the ability to move, survive, and cause infection. The flagellum is a complex nanomachine that has evolved to increase the fitness of each bacterium to diverse environments. Over several decades, molecular, biochemical, and structural insights into the flagella have led to a comprehensive understanding of the structure and function of this fascinating nanomachine. Notably, X-ray crystallography, cryo-electron microscopy (cryo-EM), and cryo-electron tomography (cryo-ET) have elucidated the flagella and their components to unprecedented resolution, gleaning insights into their structural conservation and adaptation. In this review, we focus on recent structural studies that have led to a mechanistic understanding of flagellar assembly, function, and evolution.
Collapse
|
25
|
Structure and Energy-Conversion Mechanism of the Bacterial Na+-Driven Flagellar Motor. Trends Microbiol 2020; 28:719-731. [DOI: 10.1016/j.tim.2020.03.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/16/2020] [Accepted: 03/25/2020] [Indexed: 01/09/2023]
|
26
|
In Situ Structural Analysis of Leptospira spp. by Electron Cryotomography. Methods Mol Biol 2020. [PMID: 32632865 DOI: 10.1007/978-1-0716-0459-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Spirochetes such as Treponema, Borrelia, and Leptospira species can rotate their bodies to swim in liquid environments by rotating periplasmic flagella or endoflagella, which are present inside the cell. Electron cryotomography (ECT) is an imaging technique that directly provides three-dimensional (3D) structures of cells and molecular complexes in their cellular environment at nanometer resolution. Here, I present a general protocol of ECT that covers the sample preparation, data collection, tilt series alignment, and tomographic reconstruction for visualization of intact periplasmic flagella in Leptospira spp. This protocol is capable of determining protein structures at resolutions high enough to visualize their individual domains and secondary structures in their cellular environment.
Collapse
|
27
|
Camarena L, Dreyfus G. Living in a Foster Home: The Single Subpolar Flagellum Fla1 of Rhodobacter sphaeroides. Biomolecules 2020; 10:E774. [PMID: 32429424 PMCID: PMC7277832 DOI: 10.3390/biom10050774] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/12/2020] [Accepted: 05/13/2020] [Indexed: 12/14/2022] Open
Abstract
Rhodobacter sphaeroides is an α-proteobacterium that has the particularity of having two functional flagellar systems used for swimming. Under the growth conditions commonly used in the laboratory, a single subpolar flagellum that traverses the cell membrane, is assembled on the surface. This flagellum has been named Fla1. Phylogenetic analyses have suggested that this flagellar genetic system was acquired from an ancient γ-proteobacterium. It has been shown that this flagellum has components homologous to those present in other γ-proteobacteria such as the H-ring characteristic of the Vibrio species. Other features of this flagellum such as a straight hook, and a prominent HAP region have been studied and the molecular basis underlying these features has been revealed. It has also been shown that FliL, and the protein MotF, mainly found in several species of the family Rhodobacteraceae, contribute to remodel the amphipathic region of MotB, known as the plug, in order to allow flagellar rotation. In the absence of the plug region of MotB, FliL and MotF are dispensable. In this review we have covered the most relevant aspects of the Fla1 flagellum of this remarkable photosynthetic bacterium.
Collapse
Affiliation(s)
- Laura Camarena
- Depto. Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, CDMX 04510, Mexico
| | - Georges Dreyfus
- Depto. Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, CDMX 04510, Mexico
| |
Collapse
|
28
|
Spirochete Flagella and Motility. Biomolecules 2020; 10:biom10040550. [PMID: 32260454 PMCID: PMC7225975 DOI: 10.3390/biom10040550] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/03/2020] [Accepted: 04/03/2020] [Indexed: 02/07/2023] Open
Abstract
Spirochetes can be distinguished from other flagellated bacteria by their long, thin, spiral (or wavy) cell bodies and endoflagella that reside within the periplasmic space, designated as periplasmic flagella (PFs). Some members of the spirochetes are pathogenic, including the causative agents of syphilis, Lyme disease, swine dysentery, and leptospirosis. Furthermore, their unique morphologies have attracted attention of structural biologists; however, the underlying physics of viscoelasticity-dependent spirochetal motility is a longstanding mystery. Elucidating the molecular basis of spirochetal invasion and interaction with hosts, resulting in the appearance of symptoms or the generation of asymptomatic reservoirs, will lead to a deeper understanding of host-pathogen relationships and the development of antimicrobials. Moreover, the mechanism of propulsion in fluids or on surfaces by the rotation of PFs within the narrow periplasmic space could be a designing base for an autonomously driving micro-robot with high efficiency. This review describes diverse morphology and motility observed among the spirochetes and further summarizes the current knowledge on their mechanisms and relations to pathogenicity, mainly from the standpoint of experimental biophysics.
Collapse
|
29
|
Abstract
Periplasmic flagella are complex nanomachines responsible for distinctive morphology and motility of spirochetes. Although bacterial flagella have been extensively studied for several decades in the model systems Escherichia coli and Salmonella enterica, our understanding of periplasmic flagella in many disease-causing spirochetes remains incomplete. Recent advances, including molecular genetics, biochemistry, structural biology, and cryo-electron tomography, have greatly increased our understanding of structure and function of periplasmic flagella. In this chapter, we summarize some of the recent findings that provide new insights into the structure, assembly, and function of periplasmic flagella.
Collapse
|
30
|
Zhang K, He J, Cantalano C, Guo Y, Liu J, Li C. FlhF regulates the number and configuration of periplasmic flagella in Borrelia burgdorferi. Mol Microbiol 2020; 113:1122-1139. [PMID: 32039533 DOI: 10.1111/mmi.14482] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 12/17/2022]
Abstract
The Lyme disease bacterium Borrelia burgdorferi has 7-11 periplasmic flagella (PF) that arise from the cell poles and extend toward the midcell as a flat-ribbon, which is distinct from other bacteria. FlhF, a signal recognition particle (SRP)-like GTPase, has been found to regulate the flagellar number and polarity; however, its role in B. burgdorferi remains unknown. B. burgdorferi has an FlhF homolog (BB0270). Structural and biochemical analyses show that BB0270 has a similar structure and enzymatic activity as its counterparts from other bacteria. Genetics and cryo-electron tomography studies reveal that deletion of BB0270 leads to mutant cells that have less PF (4 ± 2 PF per cell tip) and fail to form a flat-ribbon, indicative of a role of BB0270 in the control of PF number and configuration. Mechanistically, we demonstrate that BB0270 localizes at the cell poles and controls the number and position of PF via regulating the flagellar protein stability and the polar localization of the MS-ring protein FliF. Our study not only provides the detailed characterizations of BB0270 and its profound impacts on flagellar assembly, morphology and motility in B. burgdorferi, but also unveils mechanistic insights into how spirochetes control their unique flagellar patterns.
Collapse
Affiliation(s)
- Kai Zhang
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA
| | - Jun He
- Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Claudio Cantalano
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA.,Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - Youzhong Guo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA.,Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Chunhao Li
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA.,Department of Microbiology and Immunology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| |
Collapse
|
31
|
Xu H, He J, Liu J, Motaleb MA. BB0326 is responsible for the formation of periplasmic flagellar collar and assembly of the stator complex in Borrelia burgdorferi. Mol Microbiol 2019; 113:418-429. [PMID: 31743518 DOI: 10.1111/mmi.14428] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 11/15/2019] [Accepted: 11/16/2019] [Indexed: 12/19/2022]
Abstract
Borrelia burgdorferi is a highly motile spirochete due to its periplasmic flagella. Unlike flagella of other bacteria, spirochetes' periplasmic flagella possess a complex structure called the collar, about which little is known in terms of function and composition. Using various approaches, we have identified a novel protein, BB0326, as a key component of the collar. We show that a peripheral portion of the collar is diminished in the Δbb0326 mutant and restored in the complemented bb0326+ cells, leading us to rename BB0326 as periplasmic flagellar collar protein A or FlcA. The ΔflcA mutant cells produced fewer, abnormally tilted and shorter flagella, as well as diminished stators, suggesting that FlcA is crucial for flagellar and stator assemblies. We provide further evidence that FlcA interacts with the stator and that this collar-stator interaction is essential for the high torque needed to power the spirochete's periplasmic flagellar motors. These observations suggest that the collar provides various important functions to the spirochete's periplasmic flagellar assembly and rotation.
Collapse
Affiliation(s)
- Hui Xu
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Jun He
- Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale School of Medicine, New Haven, CT, USA
| | - Jun Liu
- Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale School of Medicine, New Haven, CT, USA
| | - Md A Motaleb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| |
Collapse
|
32
|
Lynch MJ, Miller M, James M, Zhang S, Zhang K, Li C, Charon NW, Crane BR. Structure and chemistry of lysinoalanine crosslinking in the spirochaete flagella hook. Nat Chem Biol 2019; 15:959-965. [PMID: 31406373 PMCID: PMC6764852 DOI: 10.1038/s41589-019-0341-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 07/08/2019] [Indexed: 11/09/2022]
Abstract
The flagellar hook protein FlgE from spirochaete bacteria self-catalyzes the formation of an unusual inter-subunit lysinoalanine (Lal) crosslink that is critical for cell motility. Unlike other known examples of Lal biosynthesis, conserved cysteine and lysine residues in FlgE spontaneously react to form Lal without the involvement of additional enzymes. Oligomerization of FlgE via its D0 and Dc domains drives assembly of the crosslinking site at the D1-D2 domain interface. Structures of the FlgED2 domain, dehydroalanine (DHA) intermediate and Lal crosslinked FlgE subunits reveal successive snapshots of the reaction. Cys178 flips from a buried configuration to release hydrogen sulfide (H2S/HS-) and produce DHA. Interface residues provide hydrogen bonds to anchor the active site, facilitate β-elimination of Cys178 and polarize the peptide backbone to activate DHA for reaction with Lys165. Cysteine-reactive molecules accelerate DHA formation, whereas nucleophiles can intercept the DHA intermediate, thereby indicating a potential for Lal crosslink inhibitors to combat spirochaetal diseases.
Collapse
Affiliation(s)
- Michael J Lynch
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Michael Miller
- Department of Biochemistry, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Milinda James
- Department of Microbiology, Immunology, and Cell Biology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Sheng Zhang
- Proteomics Facility, Institute of Biotechnology, Cornell University, Ithaca, NY, USA
| | - Kai Zhang
- Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Richmond, VA, USA
| | - Chunhao Li
- Philips Institute for Oral Health Research, Virginia Commonwealth University School of Dentistry, Richmond, VA, USA
| | - Nyles W Charon
- Department of Microbiology, Immunology, and Cell Biology, Robert C. Byrd Health Sciences Center, West Virginia University, Morgantown, WV, USA
| | - Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
| |
Collapse
|
33
|
Hirakawa H, Suzue K, Kurabayashi K, Tomita H. The Tol-Pal System of Uropathogenic Escherichia coli Is Responsible for Optimal Internalization Into and Aggregation Within Bladder Epithelial Cells, Colonization of the Urinary Tract of Mice, and Bacterial Motility. Front Microbiol 2019; 10:1827. [PMID: 31456768 PMCID: PMC6698795 DOI: 10.3389/fmicb.2019.01827] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 07/24/2019] [Indexed: 11/30/2022] Open
Abstract
Urinary tracts infection (UTI) caused by uropathogenic Escherichia coli (UPEC) is a common infectious disease. With the shortage of new antimicrobial agents, the increase in UPEC resistance to commonly used drugs, such as fluoroquinolones and β-lactams including carbapenems is a critical issue. UPEC invades urinary tract cells, where it aggregates, and subsequently, forms biofilm-like multicellular colonies termed intracellular bacterial communities (IBCs). This process allows the bacteria to establish infections and so may be a good potential target for new drugs to treat infections. Here, we show that deletion of the tolB gene, encoding a protein of the Tol-Pal system that was originally characterized as a protein complex for colicin uptake and maintenance of the outer membrane, decreases the level of bacterial internalization into and aggregation within cultured bladder epithelial cells and also inhibits the colonization of mice urinary tracts. The tolB mutant also exhibited defective motility because of impaired flagellum syntheses. The fliC and motA mutants, which are non-motile strains, also exhibited lower levels of bacterial internalization and aggregation than their wild-type parent. Additional deletion of tolB in the fliC mutant did not further decrease these, suggesting that the attenuated virulence of the tolB mutant is a result of defective motility. The tolA, tolQ, tolR, and pal mutants that lack other members of the Tol-Pal system also exhibited lower levels of motility and aggregation within bladder epithelial cells compared to their wild-type parent. These combined results suggest another role of the Tol-Pal system, i.e., that it is responsible for optimal internalization, aggregation followed by IBC formation within urinary tract cells, and bacterial motility.
Collapse
Affiliation(s)
- Hidetada Hirakawa
- Department of Bacteriology, Graduate School of Medicine, Gunma University, Gunma, Japan
| | - Kazutomo Suzue
- Department of Infectious Diseases and Host Defense, Graduate School of Medicine, Gunma University, Gunma, Japan
| | - Kumiko Kurabayashi
- Department of Bacteriology, Graduate School of Medicine, Gunma University, Gunma, Japan
| | - Haruyoshi Tomita
- Department of Bacteriology, Graduate School of Medicine, Gunma University, Gunma, Japan.,Laboratory of Bacterial Drug Resistance, Graduate School of Medicine, Gunma University, Gunma, Japan
| |
Collapse
|
34
|
Chang Y, Moon KH, Zhao X, Norris SJ, Motaleb MA, Liu J. Structural insights into flagellar stator-rotor interactions. eLife 2019; 8:48979. [PMID: 31313986 PMCID: PMC6663468 DOI: 10.7554/elife.48979] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Accepted: 07/12/2019] [Indexed: 12/25/2022] Open
Abstract
The bacterial flagellar motor is a molecular machine that can rotate the flagellar filament at high speed. The rotation is generated by the stator–rotor interaction, coupled with an ion flux through the torque-generating stator. Here we employed cryo-electron tomography to visualize the intact flagellar motor in the Lyme disease spirochete, Borrelia burgdorferi. By analyzing the motor structures of wild-type and stator-deletion mutants, we not only localized the stator complex in situ, but also revealed the stator–rotor interaction at an unprecedented detail. Importantly, the stator–rotor interaction induces a conformational change in the flagella C-ring. Given our observation that a non-motile mutant, in which proton flux is blocked, cannot generate the similar conformational change, we propose that the proton-driven torque is responsible for the conformational change required for flagellar rotation.
Collapse
Affiliation(s)
- Yunjie Chang
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States
| | - Ki Hwan Moon
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, United States
| | - Xiaowei Zhao
- Microbial Sciences Institute, Yale University, West Haven, United States.,Department of Pathology and Laboratory Medicine, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, United States
| | - Steven J Norris
- Department of Pathology and Laboratory Medicine, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, United States
| | - Md A Motaleb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, United States
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, United States.,Microbial Sciences Institute, Yale University, West Haven, United States.,Department of Pathology and Laboratory Medicine, McGovern Medical School at University of Texas Health Science Center at Houston, Houston, United States
| |
Collapse
|
35
|
Kaplan M, Subramanian P, Ghosal D, Oikonomou CM, Pirbadian S, Starwalt‐Lee R, Mageswaran SK, Ortega DR, Gralnick JA, El‐Naggar MY, Jensen GJ. In situ imaging of the bacterial flagellar motor disassembly and assembly processes. EMBO J 2019; 38:e100957. [PMID: 31304634 PMCID: PMC6627242 DOI: 10.15252/embj.2018100957] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 04/11/2019] [Accepted: 04/18/2019] [Indexed: 11/09/2022] Open
Abstract
The self-assembly of cellular macromolecular machines such as the bacterial flagellar motor requires the spatio-temporal synchronization of gene expression with proper protein localization and association of dozens of protein components. In Salmonella and Escherichia coli, a sequential, outward assembly mechanism has been proposed for the flagellar motor starting from the inner membrane, with the addition of each new component stabilizing the previous one. However, very little is known about flagellar disassembly. Here, using electron cryo-tomography and sub-tomogram averaging of intact Legionella pneumophila, Pseudomonas aeruginosa, and Shewanella oneidensis cells, we study flagellar motor disassembly and assembly in situ. We first show that motor disassembly results in stable outer membrane-embedded sub-complexes. These sub-complexes consist of the periplasmic embellished P- and L-rings, and bend the membrane inward while it remains apparently sealed. Additionally, we also observe various intermediates of the assembly process including an inner-membrane sub-complex consisting of the C-ring, MS-ring, and export apparatus. Finally, we show that the L-ring is responsible for reshaping the outer membrane, a crucial step in the flagellar assembly process.
Collapse
Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Poorna Subramanian
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Debnath Ghosal
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Catherine M Oikonomou
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Sahand Pirbadian
- Department of Physics and Astronomy, Biological Sciences, and ChemistryUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Ruth Starwalt‐Lee
- BioTechnology InstituteUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
| | | | - Davi R Ortega
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
| | - Jeffrey A Gralnick
- BioTechnology InstituteUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
- Department of Plant and Microbial BiologyUniversity of Minnesota – Twin CitiesSt. PaulMNUSA
| | - Mohamed Y El‐Naggar
- Department of Physics and Astronomy, Biological Sciences, and ChemistryUniversity of Southern CaliforniaLos AngelesCAUSA
| | - Grant J Jensen
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaCAUSA
- Howard Hughes Medical InstituteCalifornia Institute of TechnologyPasadenaCAUSA
| |
Collapse
|
36
|
Hummels KR, Kearns DB. Suppressor mutations in ribosomal proteins and FliY restore Bacillus subtilis swarming motility in the absence of EF-P. PLoS Genet 2019; 15:e1008179. [PMID: 31237868 PMCID: PMC6613710 DOI: 10.1371/journal.pgen.1008179] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 07/08/2019] [Accepted: 05/07/2019] [Indexed: 11/19/2022] Open
Abstract
Translation elongation factor P (EF-P) alleviates ribosome pausing at a subset of motifs encoding consecutive proline residues, and is required for growth in many organisms. Here we show that Bacillus subtilis EF-P also alleviates ribosome pausing at sequences encoding tandem prolines and ribosomes paused within several essential genes without a corresponding growth defect in an efp mutant. The B. subtilis efp mutant is instead impaired for flagellar biosynthesis which results in the abrogation of a form of motility called swarming. We isolate swarming suppressors of efp and identify mutations in 8 genes that suppressed the efp mutant swarming defect, many of which encode conserved ribosomal proteins or ribosome-associated factors. One mutation abolished a translational pause site within the flagellar C-ring component FliY to increase flagellar number and restore swarming motility in the absence of EF-P. Our data support a model wherein EF-P-alleviation of ribosome pausing may be particularly important for macromolecular assemblies like the flagellum that require precise protein stoichiometries.
Collapse
Affiliation(s)
- Katherine R. Hummels
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Daniel B. Kearns
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
| |
Collapse
|
37
|
Abstract
Helicobacter pylori colonizes about half of humans worldwide, and its presence in the gastric mucosa is associated with an increased risk of gastric adenocarcinoma, gastric lymphoma, and peptic ulcer disease. H. pylori strains carrying the cag pathogenicity island (cagPAI) are associated with increased risk of disease progression. The cagPAI encodes the Cag type IV secretion system (CagT4SS), which delivers the CagA oncoprotein and other effector molecules into human gastric epithelial cells. We visualized structures of native and mutant CagT4SS machines on the H. pylori cell envelope by cryoelectron tomography. Individual H. pylori cells contain multiple CagT4SS nanomachines, each composed of a wheel-shaped outer membrane complex (OMC) with 14-fold symmetry and an inner membrane complex (IMC) with 6-fold symmetry. CagX, CagY, and CagM are required for assembly of the OMC, whereas strains lacking Cag3 and CagT produce outer membrane complexes lacking peripheral components. The IMC, which has never been visualized in detail, is configured as six tiers in cross-section view and three concentric rings surrounding a central channel in end-on view. The IMC contains three T4SS ATPases: (i) VirB4-like CagE, arranged as a hexamer of dimers at the channel entrance; (ii) a hexamer of VirB11-like Cagα, docked at the base of the CagE hexamer; and (iii) VirD4-like Cagβ and other unspecified Cag subunits, associated with the stacked CagE/Cagα complex and forming the outermost rings. The CagT4SS and recently solved Legionella pneumophila Dot/Icm system comprise new structural prototypes for the T4SS superfamily.IMPORTANCE Bacterial type IV secretion systems (T4SSs) have been phylogenetically grouped into two subfamilies. The T4ASSs, represented by the Agrobacterium tumefaciens VirB/VirD4T4SS, include "minimized" machines assembled from 12 VirB- and VirD4-like subunits and compositionally larger systems such as the Helicobacter pylori CagT4SS T4BSSs encompass systems closely related in subunit composition to the Legionella pneumophila Dot/IcmT4SS Here, we present structures of native and mutant H. pylori Cag machines determined by in situ cryoelectron tomography. We identify distinct outer and inner membrane complexes and, for the first time, visualize structural contributions of all three "signature" ATPases of T4SSs at the cytoplasmic entrance of the translocation channel. Despite their evolutionary divergence, the CagT4SS aligns structurally much more closely to the Dot/IcmT4SS than an available VirB/VirD4 subcomplex. Our findings highlight the diversity of T4SSs and suggest a structural classification scheme in which T4SSs are grouped as minimized VirB/VirD4-like or larger Cag-like and Dot/Icm-like systems.
Collapse
|
38
|
Zhang K, Qin Z, Chang Y, Liu J, Malkowski MG, Shipa S, Li L, Qiu W, Zhang JR, Li C. Analysis of a flagellar filament cap mutant reveals that HtrA serine protease degrades unfolded flagellin protein in the periplasm of Borrelia burgdorferi. Mol Microbiol 2019; 111:1652-1670. [PMID: 30883947 DOI: 10.1111/mmi.14243] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2019] [Indexed: 12/16/2022]
Abstract
Unlike external flagellated bacteria, spirochetes have periplasmic flagella (PF). Very little is known about how PF are assembled within the periplasm of spirochaetal cells. Herein, we report that FliD (BB0149), a flagellar cap protein (also named hook-associated protein 2), controls flagellin stability and flagellar filament assembly in the Lyme disease spirochete Borrelia burgdorferi. Deletion of fliD leads to non-motile mutant cells that are unable to assemble flagellar filaments and pentagon-shaped caps (10 nm in diameter, 12 nm in length). Interestingly, FlaB, a major flagellin protein of B. burgdorferi, is degraded in the fliD mutant but not in other flagella-deficient mutants (i.e., in the hook, rod, or MS-ring). Biochemical and genetic studies reveal that HtrA, a serine protease of B. burgdorferi, controls FlaB turnover. Specifically, HtrA degrades unfolded but not polymerized FlaB, and deletion of htrA increases the level of FlaB in the fliD mutant. Collectively, we propose that the flagellar cap protein FliD promotes flagellin polymerization and filament growth in the periplasm. Deletion of fliD abolishes this process, which leads to leakage of unfolded FlaB proteins into the periplasm where they are degraded by HtrA, a protease that prevents accumulation of toxic products in the periplasm.
Collapse
Affiliation(s)
- Kai Zhang
- Department of Oral and Craniofacial Molecular Biology, Philips Research Institute, Virginia Commonwealth University, Richmond, VI, 23298, USA
| | - Zhuan Qin
- Department of Microbial Pathogenesis & Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, 06516, USA
| | - Yunjie Chang
- Department of Microbial Pathogenesis & Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, 06516, USA
| | - Jun Liu
- Department of Microbial Pathogenesis & Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, 06516, USA
| | - Michael G Malkowski
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, Buffalo, NY, 14203, USA
| | - Saimtun Shipa
- Department of Biological Sciences, City University of New York, New York, NY, 10021, USA
| | - Li Li
- Department of Biological Sciences, City University of New York, New York, NY, 10021, USA
| | - Weigang Qiu
- Department of Biological Sciences, City University of New York, New York, NY, 10021, USA
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Chunhao Li
- Department of Oral and Craniofacial Molecular Biology, Philips Research Institute, Virginia Commonwealth University, Richmond, VI, 23298, USA
| |
Collapse
|
39
|
Chen S, Wang Y, Nie T, Bao C, Wang C, Xu T, Lin Q, Qu DH, Gong X, Yang Y, Zhu L, Tian H. An Artificial Molecular Shuttle Operates in Lipid Bilayers for Ion Transport. J Am Chem Soc 2018; 140:17992-17998. [PMID: 30445811 DOI: 10.1021/jacs.8b09580] [Citation(s) in RCA: 126] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Inspired by natural biomolecular machines, synthetic molecular-level machines have been proven to perform well-defined mechanical tasks and measurable work. To mimic the function of channel proteins, we herein report the development of a synthetic molecular shuttle, [2]rotaxane 3, as a unimolecular vehicle that can be inserted into lipid bilayers to perform passive ion transport through its stochastic shuttling motion. The [2]rotaxane molecular shuttle is composed of an amphiphilic molecular thread with three binding stations, which is interlocked in a macrocycle wheel component that tethers a K+ carrier. The structural characteristics enable the rotaxane to transport ions across the lipid bilayers, similar to a cable car, transporting K+ with an EC50 value of 1.0 μM (3.0 mol % relative to lipid). We expect that this simple molecular machine will provide new opportunities for developing more effective and selective ion transporters.
Collapse
Affiliation(s)
- Sujun Chen
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Yichuan Wang
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Ting Nie
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Chunyan Bao
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Chenxi Wang
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Tianyi Xu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Qiuning Lin
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Da-Hui Qu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Xueqing Gong
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Yi Yang
- Optogenetics & Synthetic Biology Interdisciplinary Research Center, State Key Laboratory of Bioreactor Engineering, School of Pharmacy , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - Linyong Zhu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| | - He Tian
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, School of Chemistry and Molecular Engineering , East China University of Science & Technology , 130 Meilong Road , Shanghai , 200237 , China
| |
Collapse
|
40
|
Cryo-electron tomography of periplasmic flagella in Borrelia burgdorferi reveals a distinct cytoplasmic ATPase complex. PLoS Biol 2018; 16:e3000050. [PMID: 30412577 PMCID: PMC6248999 DOI: 10.1371/journal.pbio.3000050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 11/21/2018] [Accepted: 10/23/2018] [Indexed: 12/25/2022] Open
Abstract
Periplasmic flagella are essential for the distinct morphology and motility of spirochetes. A flagella-specific type III secretion system (fT3SS) composed of a membrane-bound export apparatus and a cytosolic ATPase complex is responsible for the assembly of the periplasmic flagella. Here, we deployed cryo-electron tomography (cryo-ET) to visualize the fT3SS machine in the Lyme disease spirochete Borrelia burgdorferi. We show, for the first time, that the cytosolic ATPase complex is attached to the flagellar C-ring through multiple spokes to form the “spoke and hub” structure in B. burgdorferi. This structure not only strengthens structural rigidity of the round-shaped C-ring but also appears to rotate with the C-ring. Our studies provide structural insights into the unique mechanisms underlying assembly and rotation of the periplasmic flagella and may provide the basis for the development of novel therapeutic strategies against several pathogenic spirochetes. Cryo-electron tomography of periplasmic flagella in the Lyme disease bacterium Borrelia burgdorferi reveals it to have a distinct cytoplasmic ATPase complex and an atypical interaction with the flagellar C-ring. Type III secretion systems are widely utilized by gram-negative bacteria to assemble flagella or to transport virulence effectors into eukaryotic cells. The central component is known as a type III secretion machine, which consists of a membrane-bound export apparatus and a cytosolic ATPase complex. Powered by the proton motive force and ATP hydrolysis, the secretion machine is responsible for substrate recognition and export. Here, we use the Lyme disease spirochete B. burgdorferi as a model system to unveil unprecedented structural details of the intact flagellar secretion machine by high-throughput cryo-electron tomography (cryo-ET) and subtomogram averaging. We provide the first structural evidence that the cytosolic ATPase complex is attached to the flagellar C-ring through multiple spokes to form the “spoke and hub” structure in B. burgdorferi. The novel architecture of the ATPase complex not only strengthens the flagellar C-ring but also enables an optimal translocation of substrates through the ATPase complex and the export apparatus.
Collapse
|
41
|
Assembly Order of Flagellar Rod Subunits in Bacillus subtilis. J Bacteriol 2018; 200:JB.00425-18. [PMID: 30201778 DOI: 10.1128/jb.00425-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/05/2018] [Indexed: 11/20/2022] Open
Abstract
Bacterial flagella contain an axle-like rod that transits the cell envelope and connects the transmembrane basal body to the extracellular hook and filament. Although the rod is a crucial component of the flagellum, its structure and assembly are poorly understood. Previous reports defining the order of rod assembly in Gram-negative bacteria suggest that the rod requires five proteins to successfully assemble, but assembly intermediates have not been well characterized due to metastability and periplasmic proteolysis. Bacillus subtilis is a Gram-positive, genetically tractable model bacterium that synthesizes flagella and lacks a true periplasm. Here, we genetically, biochemically, and cytologically determine the assembly order of the flagellar rod proteins from cell proximal to distal as FliE, FlgB, FlgC, FlhO, and FlhP. We further show that, under conditions in which rod structure cannot be completed, assembly intermediates are both metastable and subject to proteolysis. Finally, we support previous results that FliE serves as both a structural assembly platform for the rod and as an enhancer of flagellar type III secretion.IMPORTANCE Bacteria rotate propeller-like flagella to find and colonize environmental niches. The flagellum is a complex machine, and the understanding of its structure is still incomplete. Here, we characterize and biochemically define the assembly order of the subunits that make up the axle-like rod. The rod is a critical structure for the assembly of subsequent components and is central to our understanding of how the flagellum is anchored but still free spinning within the context of the cell envelope.
Collapse
|
42
|
Moon KH, Zhao X, Xu H, Liu J, Motaleb MA. A tetratricopeptide repeat domain protein has profound effects on assembly of periplasmic flagella, morphology and motility of the lyme disease spirochete Borrelia burgdorferi. Mol Microbiol 2018; 110:634-647. [PMID: 30303576 DOI: 10.1111/mmi.14121] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2018] [Indexed: 02/07/2023]
Abstract
Spirochetes possess a unique periplasmic flagellar motor component called the collar. However, little is known about the composition or function of the flagellar collar proteins. To identify a collar protein, we have inactivated almost all genes annotated as motility-related in the Borrelia burgdorferi genome and identified only FlbB, which comprises the base of the collar. Since the major components of the collar complex remained unidentified, we took advantage of a protein-protein interaction map developed in another spirochete, Treponema pallidum to identify proteins of unknown function that could be collar proteins. Subsequently, using various comprehensive approaches, we identified a tetratricopeptide repeat protein BB0236 as a potential candidate for the collar. Biochemical assays indicated that FlbB interacts with BB0236. Furthermore, ∆bb0236 mutant analyses indicated that BB0236 is crucial for collar structure assembly, cellular morphology, motility, orientation of periplasmic flagella and assembly of other flagellar structures. Moreover, using comparative motor analyses, we propose how the collar structure is assembled in B. burgdorferi. Together, our studies provide new insights into the organization and the complex assembly inherent to the unique spirochetal collar structure.
Collapse
Affiliation(s)
- Ki Hwan Moon
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Xiaowei Zhao
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, TX, 77030, USA
| | - Hui Xu
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Jun Liu
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, TX, 77030, USA.,Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale University, New Haven, CT, 06536, USA
| | - Md A Motaleb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| |
Collapse
|
43
|
The Vibrio H-Ring Facilitates the Outer Membrane Penetration of the Polar Sheathed Flagellum. J Bacteriol 2018; 200:JB.00387-18. [PMID: 30104237 DOI: 10.1128/jb.00387-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/09/2018] [Indexed: 12/20/2022] Open
Abstract
The bacterial flagellum has evolved as one of the most remarkable nanomachines in nature. It provides swimming and swarming motilities that are often essential for the bacterial life cycle and pathogenesis. Many bacteria such as Salmonella and Vibrio species use flagella as an external propeller to move to favorable environments, whereas spirochetes utilize internal periplasmic flagella to drive a serpentine movement of the cell bodies through tissues. Here, we use cryo-electron tomography to visualize the polar sheathed flagellum of Vibrio alginolyticus with particular focus on a Vibrio-specific feature, the H-ring. We characterized the H-ring by identifying its two components FlgT and FlgO. We found that the majority of flagella are located within the periplasmic space in the absence of the H-ring, which are different from those of external flagella in wild-type cells. Our results not only indicate the H-ring has a novel function in facilitating the penetration of the outer membrane and the assembly of the external sheathed flagella but also are consistent with the notion that the flagella have evolved to adapt highly diverse needs by receiving or removing accessary genes.IMPORTANCE Flagellum is the major organelle for motility in many bacterial species. While most bacteria possess external flagella, such as the multiple peritrichous flagella found in Escherichia coli and Salmonella enterica or the single polar sheathed flagellum in Vibrio spp., spirochetes uniquely assemble periplasmic flagella, which are embedded between their inner and outer membranes. Here, we show for the first time that the external flagella in Vibrio alginolyticus can be changed as periplasmic flagella by deleting two flagellar genes. The discovery here may provide new insights into the molecular basis underlying assembly, diversity, and evolution of flagella.
Collapse
|
44
|
Kuhlen L, Abrusci P, Johnson S, Gault J, Deme J, Caesar J, Dietsche T, Mebrhatu MT, Ganief T, Macek B, Wagner S, Robinson CV, Lea SM. Structure of the core of the type III secretion system export apparatus. Nat Struct Mol Biol 2018; 25:583-590. [PMID: 29967543 PMCID: PMC6233869 DOI: 10.1038/s41594-018-0086-9] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 06/01/2018] [Indexed: 12/04/2022]
Abstract
Export of proteins through type III secretion systems is critical for motility and virulence of many major bacterial pathogens. Three putative integral membrane proteins (FliP, FliQ, FliR) are suggested to form the core of an export gate in the inner membrane, but their structure, assembly and location within the final nanomachine remain unclear. Here, we present the cryoelectron microscopy structure of the Salmonella Typhimurium FliP-FliQ-FliR complex at 4.2 Å. None of the subunits adopt canonical integral membrane protein topologies, and common helix-turn-helix structural elements allow them to form a helical assembly with 5:4:1 stoichiometry. Fitting of the structure into reconstructions of intact secretion systems, combined with cross-linking, localize the export gate as a core component of the periplasmic portion of the machinery. This study thereby identifies the export gate as a key element of the secretion channel and implies that it primes the helical architecture of the components assembling downstream.
Collapse
Affiliation(s)
- Lucas Kuhlen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Patrizia Abrusci
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Joseph Gault
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Justin Deme
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford, UK
| | - Joseph Caesar
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford, UK
| | - Tobias Dietsche
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Mehari Tesfazgi Mebrhatu
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
| | - Tariq Ganief
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, University of Tübingen, Tübingen, Germany
| | - Samuel Wagner
- Section of Cellular and Molecular Microbiology, Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, Tübingen, Germany
- German Center for Infection Research, Partner-site Tübingen, Tübingen, Germany
| | | | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Central Oxford Structural Microscopy and Imaging Centre, University of Oxford, Oxford, UK.
| |
Collapse
|
45
|
Rossmann FM, Beeby M. Insights into the evolution of bacterial flagellar motors from high-throughput in situ electron cryotomography and subtomogram averaging. Acta Crystallogr D Struct Biol 2018; 74:585-594. [PMID: 29872008 PMCID: PMC6096493 DOI: 10.1107/s2059798318007945] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 05/29/2018] [Indexed: 12/29/2022] Open
Abstract
In situ structural information on molecular machines can be invaluable in understanding their assembly, mechanism and evolution. Here, the use of electron cryotomography (ECT) to obtain significant insights into how an archetypal molecular machine, the bacterial flagellar motor, functions and how it has evolved is described. Over the last decade, studies using a high-throughput, medium-resolution ECT approach combined with genetics, phylogenetic reconstruction and phenotypic analysis have revealed surprising structural diversity in flagellar motors. Variations in the size and the number of torque-generating proteins in the motor visualized for the first time using ECT has shown that these variations have enabled bacteria to adapt their swimming torque to the environment. Much of the structural diversity can be explained in terms of scaffold structures that facilitate the incorporation of additional motor proteins, and more recent studies have begun to infer evolutionary pathways to higher torque-producing motors. This review seeks to highlight how the emerging power of ECT has enabled the inference of ancestral states from various bacterial species towards understanding how, and `why', flagellar motors have evolved from an ancestral motor to a diversity of variants with adapted or modified functions.
Collapse
Affiliation(s)
- Florian M. Rossmann
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London SW7 2AZ, England
| |
Collapse
|
46
|
Neuberger A, Du D, Luisi BF. Structure and mechanism of bacterial tripartite efflux pumps. Res Microbiol 2018; 169:401-413. [PMID: 29787834 DOI: 10.1016/j.resmic.2018.05.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 02/20/2018] [Accepted: 05/14/2018] [Indexed: 12/22/2022]
Abstract
Efflux pumps are membrane proteins which contribute to multi-drug resistance. In Gram-negative bacteria, some of these pumps form complex tripartite assemblies in association with an outer membrane channel and a periplasmic membrane fusion protein. These tripartite machineries span both membranes and the periplasmic space, and they extrude from the bacterium chemically diverse toxic substrates. In this chapter, we summarise current understanding of the structural architecture, functionality, and regulation of tripartite multi-drug efflux assemblies.
Collapse
Affiliation(s)
- Arthur Neuberger
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Dijun Du
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK
| | - Ben F Luisi
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1GA, UK.
| |
Collapse
|
47
|
Cyrklaff M, Frischknecht F, Kudryashev M. Functional insights into pathogen biology from 3D electron microscopy. FEMS Microbiol Rev 2018; 41:828-853. [PMID: 28962014 DOI: 10.1093/femsre/fux041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 07/25/2017] [Indexed: 01/10/2023] Open
Abstract
In recent years, novel imaging approaches revolutionised our understanding of the cellular and molecular biology of microorganisms. These include advances in fluorescent probes, dynamic live cell imaging, superresolution light and electron microscopy. Currently, a major transition in the experimental approach shifts electron microscopy studies from a complementary technique to a method of choice for structural and functional analysis. Here we review functional insights into the molecular architecture of viruses, bacteria and parasites as well as interactions with their respective host cells gained from studies using cryogenic electron tomography and related methodologies.
Collapse
Affiliation(s)
- Marek Cyrklaff
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Friedrich Frischknecht
- Integrative Parasitology, Center for Infectious Diseases, Heidelberg University Medical School, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Mikhail Kudryashev
- Max Planck Institute of Biophysics, Max-von-Laue Strasse 3, 60438 Frankfurt, Germany.,Buchmann Institute for Molecular Life Sciences, Goethe University of Frankfurt, Max-von-Laue Strasse 17, 60438 Frankfurt, Germany
| |
Collapse
|
48
|
Abstract
Swimming plate, cell motion tracking, and capillary tube assays are very useful tools to quantitatively measure bacterial motility and chemotaxis. These methods were modified and applied to study Borrelia burgdorferi motility and chemotaxis. By using these methods, numerous motility and chemotaxis mutants have been characterized and several chemoattractants were identified. With the assistance of these tools, the role of motility and chemotaxis in the pathogenicity of B. burgdorferi has been established. In addition, these tools also facilitate the study of motility and chemotaxis in other spirochetes.
Collapse
Affiliation(s)
- Kai Zhang
- Department of Oral Biology, Microbiology and Immunology, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY, USA
| | - Chunhao Li
- Department of Oral Biology, Microbiology and Immunology, State University of New York at Buffalo, 3435 Main Street, Buffalo, NY, USA.
| |
Collapse
|
49
|
Henderson LD, Beeby M. High-Throughput Electron Cryo-tomography of Protein Complexes and Their Assembly. Methods Mol Biol 2018; 1764:29-44. [PMID: 29605906 DOI: 10.1007/978-1-4939-7759-8_2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Electron cryo-tomography and subtomogram averaging enable visualization of protein complexes in situ, in three dimensions, in a near-native frozen-hydrated state to nanometer resolutions. To achieve this, intact cells are vitrified and imaged over a range of tilts within an electron microscope. These images can subsequently be reconstructed into a three-dimensional volume representation of the sample cell. Because complexes are visualized in situ, crucial insights into their mechanism, assembly process, and dynamic interactions with other proteins become possible. To illustrate the electron cryo-tomography workflow for visualizing protein complexes in situ, we describe our workflow of preparing samples, imaging, and image processing using Leginon for data collection, IMOD for image reconstruction, and PEET for subtomogram averaging.
Collapse
Affiliation(s)
| | - Morgan Beeby
- Department of Life Sciences, Imperial College of London, London, UK.
| |
Collapse
|
50
|
Structural Biology in Situ Using Cryo-Electron Subtomogram Analysis. BIOLOGICAL AND MEDICAL PHYSICS, BIOMEDICAL ENGINEERING 2018. [DOI: 10.1007/978-3-319-68997-5_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|