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Gahlot DK, Taheri N, MacIntyre S. Diversity in Genetic Regulation of Bacterial Fimbriae Assembled by the Chaperone Usher Pathway. Int J Mol Sci 2022; 24:ijms24010161. [PMID: 36613605 PMCID: PMC9820224 DOI: 10.3390/ijms24010161] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 12/24/2022] Open
Abstract
Bacteria express different types of hair-like proteinaceous appendages on their cell surface known as pili or fimbriae. These filamentous structures are primarily involved in the adherence of bacteria to both abiotic and biotic surfaces for biofilm formation and/or virulence of non-pathogenic and pathogenic bacteria. In pathogenic bacteria, especially Gram-negative bacteria, fimbriae play a key role in bacteria-host interactions which are critical for bacterial invasion and infection. Fimbriae assembled by the Chaperone Usher pathway (CUP) are widespread within the Enterobacteriaceae, and their expression is tightly regulated by specific environmental stimuli. Genes essential for expression of CUP fimbriae are organised in small blocks/clusters, which are often located in proximity to other virulence genes on a pathogenicity island. Since these surface appendages play a crucial role in bacterial virulence, they have potential to be harnessed in vaccine development. This review covers the regulation of expression of CUP-assembled fimbriae in Gram-negative bacteria and uses selected examples to demonstrate both dedicated and global regulatory mechanisms.
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Affiliation(s)
- Dharmender K. Gahlot
- School of Biological Sciences, University of Reading, Reading RG6 6EX, UK
- Department of Molecular Biology, Umeå University, 901 87 Umeå, Sweden
- Umeå Centre for Microbial Research (UCMR), Umeå University, 901 87 Umeå, Sweden
- Correspondence: (D.K.G.); (S.M.)
| | - Nayyer Taheri
- APC Microbiome Institute, University College Cork, T12 K8AF Cork, Ireland
| | - Sheila MacIntyre
- School of Biological Sciences, University of Reading, Reading RG6 6EX, UK
- Correspondence: (D.K.G.); (S.M.)
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2
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Pakharukova N, Malmi H, Tuittila M, Dahlberg T, Ghosal D, Chang YW, Myint SL, Paavilainen S, Knight SD, Lamminmäki U, Uhlin BE, Andersson M, Jensen G, Zavialov AV. Archaic chaperone-usher pili self-secrete into superelastic zigzag springs. Nature 2022; 609:335-340. [PMID: 35853476 PMCID: PMC9452303 DOI: 10.1038/s41586-022-05095-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 07/08/2022] [Indexed: 11/23/2022]
Abstract
Adhesive pili assembled through the chaperone-usher pathway are hair-like appendages that mediate host tissue colonization and biofilm formation of Gram-negative bacteria1-3. Archaic chaperone-usher pathway pili, the most diverse and widespread chaperone-usher pathway adhesins, are promising vaccine and drug targets owing to their prevalence in the most troublesome multidrug-resistant pathogens1,4,5. However, their architecture and assembly-secretion process remain unknown. Here, we present the cryo-electron microscopy structure of the prototypical archaic Csu pilus that mediates biofilm formation of Acinetobacter baumannii-a notorious multidrug-resistant nosocomial pathogen. In contrast to the thick helical tubes of the classical type 1 and P pili, archaic pili assemble into an ultrathin zigzag architecture secured by an elegant clinch mechanism. The molecular clinch provides the pilus with high mechanical stability as well as superelasticity, a property observed for the first time, to our knowledge, in biomolecules, while enabling a more economical and faster pilus production. Furthermore, we demonstrate that clinch formation at the cell surface drives pilus secretion through the outer membrane. These findings suggest that clinch-formation inhibitors might represent a new strategy to fight multidrug-resistant bacterial infections.
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Affiliation(s)
- Natalia Pakharukova
- Joint Biotechnology Laboratory, MediCity, Faculty of Medicine, University of Turku, Turku, Finland
| | - Henri Malmi
- Joint Biotechnology Laboratory, MediCity, Faculty of Medicine, University of Turku, Turku, Finland
| | - Minna Tuittila
- Joint Biotechnology Laboratory, MediCity, Faculty of Medicine, University of Turku, Turku, Finland
| | - Tobias Dahlberg
- Department of Physics, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Division of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Yi-Wei Chang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Si Lhyam Myint
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Sari Paavilainen
- Joint Biotechnology Laboratory, MediCity, Faculty of Medicine, University of Turku, Turku, Finland
| | - Stefan David Knight
- Department of Cell and Molecular Biology, Biomedical Centre, Uppsala University, Uppsala, Sweden
| | - Urpo Lamminmäki
- Department of Life Technologies, University of Turku, Turku, Finland
| | - Bernt Eric Uhlin
- Department of Molecular Biology, The Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Magnus Andersson
- Department of Physics, Umeå Centre for Microbial Research (UCMR), Umeå University, Umeå, Sweden
| | - Grant Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Anton V Zavialov
- Joint Biotechnology Laboratory, MediCity, Faculty of Medicine, University of Turku, Turku, Finland.
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3
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Bai Y, Rizzo MR, Parise C, Maes S, Eisen RJ. A Novel Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Yersinia pestis. Front Microbiol 2022; 13:863142. [PMID: 35464914 PMCID: PMC9022072 DOI: 10.3389/fmicb.2022.863142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Rapid detection of Yersinia pestis, the causative agent of plague, is essential during field investigations to enable prompt control measures for prevention of the spread of the disease. Affordable, efficient, reliable, and simple detection assays are extremely useful, particularly in plague-endemic regions with limited resources. We developed a loop-mediated isothermal amplification (LAMP) assay that detects Y. pestis within 30 min by simply incubating at 65°C on a dry bath heater. The assay targeted the caf1A gene that is situated on the pMT1 plasmid using six specific primers. Y. pestis presence is visually detected based on the color change in the reactions. For comparison of the assay performance, a real-time LAMP with fluorescent dye detection was conducted on a real-time PCR instrument using the same six primers. Sensitivity assessment showed that the limit of detection (LOD) was 0.2 and 0.03 pg when performed on the dry bath heater and on the real-time PCR instrument, respectively. The assay was 100% specific, having no cross-reactivity with closely related Yersinia spp. and other bacterial species. We tested the LAMP assay on field-collected fleas and showed that it successfully detected Y. pestis with identical results to that of a previously published pentaplex real-time PCR assay. These findings suggest that the relatively inexpensive and simpler LAMP assay could be used to support field investigations, yielding comparable results to more expensive and complex PCR assays.
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Affiliation(s)
- Ying Bai
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Maria Rosales Rizzo
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Christina Parise
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Sarah Maes
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Rebecca J Eisen
- Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
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4
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Optimised Heterologous Expression and Functional Analysis of the Yersinia pestis F1-Capsular Antigen Regulator Caf1R. Int J Mol Sci 2021; 22:ijms22189805. [PMID: 34575967 PMCID: PMC8470410 DOI: 10.3390/ijms22189805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 12/14/2022] Open
Abstract
The bacterial pathogen, Yersinia pestis, has caused three historic pandemics and continues to cause small outbreaks worldwide. During infection, Y. pestis assembles a capsule-like protective coat of thin fibres of Caf1 subunits. This F1 capsular antigen has attracted much attention due to its clinical value in plague diagnostics and anti-plague vaccine development. Expression of F1 is tightly regulated by a transcriptional activator, Caf1R, of the AraC/XylS family, proteins notoriously prone to aggregation. Here, we have optimised the recombinant expression of soluble Caf1R. Expression from the native and synthetic codon-optimised caf1R cloned in three different expression plasmids was examined in a library of E. coli host strains. The functionality of His-tagged Caf1R was demonstrated in vivo, but insolubility was a problem with overproduction. High levels of soluble MBP-Caf1R were produced from codon optimised caf1R. Transcriptional-lacZ reporter fusions defined the PM promoter and Caf1R binding site responsible for transcription of the cafMA1 operon. Use of the identified Caf1R binding caf DNA sequence in an electrophoretic mobility shift assay (EMSA) confirmed correct folding and functionality of the Caf1R DNA-binding domain in recombinant MBP-Caf1R. Availability of functional recombinant Caf1R will be a valuable tool to elucidate control of expression of F1 and Caf1R-regulated pathophysiology of Y. pestis.
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Liu Y, Sun C, Han L, Yu Y, Zhou H, Shao Q, Lou J, Zhao Y, Huang Y. Conformational Dynamics, Intramolecular Domain Conformation Signaling, and Activation of Apo-FimD Revealed by Single-Molecule Fluorescence Resonance Energy Transfer Studies. Biochemistry 2019; 58:1931-1941. [PMID: 30888187 DOI: 10.1021/acs.biochem.9b00080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chaperone-usher secretion pathway is a conserved bacterial protein secretion system dedicated to the biogenesis of adhesive fibers. Usher, a multidomain-containing outer membrane protein, plays a central role in this process by acting as a molecular machine that recruits different chaperone-subunit complexes, catalyzes subunit polymerization, and forms a channel for secretion of the assembled subunits. While recent crystal structural studies have greatly advanced our understanding of the structure and function of ushers, the overall architecture of the full-length apo-usher, the molecular events that dictate conformational changes in usher during pilus biogenesis, and its activation by the specific chaperone-adhesin complex remain largely elusive. Using single-molecule fluorescence resonance energy transfer studies, we found that the substrate-free usher FimD (apo-FimD) adopts a contracted conformation that is distinct from its substrate-bound states; both the N-terminal domain (NTD) and the C-terminal domain (CTD) of apo-FimD are highly dynamic, and FimD coordinates its domain conformational changes via intramolecular domain conformation signaling. By combining these studies with in vitro photo-cross-linking studies, we further show that only the chaperone-bound adhesin (FimC:FimH) can be transferred to the CTD, dislocates the plug domain, and triggers conformational changes in the remaining FimD domains. Taken together, these studies delineate an overall architecture of the full-length apo-FimD, provide detailed mechanic insight into the activation of apo-FimD, and explain why FimD could adjust its conformational states to perform multiple functions in each cycle of pilus subunit addition and ensure that pilus assembly proceeds progressively in a cellular energy-free environment.
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Affiliation(s)
- Yanqing Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics , Chinese Academy of Sciences , 15 Datun Road , Chaoyang District, Beijing 100101 , China.,University of Chinese Academy of Sciences , Beijing 100101 , China
| | - Chuanqi Sun
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics , Chinese Academy of Sciences , 15 Datun Road , Chaoyang District, Beijing 100101 , China.,University of Chinese Academy of Sciences , Beijing 100101 , China
| | - Long Han
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics , Chinese Academy of Sciences , 15 Datun Road , Chaoyang District, Beijing 100101 , China.,University of Chinese Academy of Sciences , Beijing 100101 , China
| | - Yuqi Yu
- Drug Discovery and Design Center, CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica , Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai 201203 , China
| | - Haizhen Zhou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics , Chinese Academy of Sciences , 15 Datun Road , Chaoyang District, Beijing 100101 , China
| | - Qiang Shao
- Drug Discovery and Design Center, CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica , Chinese Academy of Sciences , 555 Zuchongzhi Road , Shanghai 201203 , China
| | - Jizhong Lou
- University of Chinese Academy of Sciences , Beijing 100101 , China.,Key Laboratory of RNA Biology, Institute of Biophysics , Chinese Academy of Sciences , Beijing 100101 , China
| | - Yongfang Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics , Chinese Academy of Sciences , 15 Datun Road , Chaoyang District, Beijing 100101 , China.,University of Chinese Academy of Sciences , Beijing 100101 , China
| | - Yihua Huang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics , Chinese Academy of Sciences , 15 Datun Road , Chaoyang District, Beijing 100101 , China.,University of Chinese Academy of Sciences , Beijing 100101 , China
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6
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The pilus usher controls protein interactions via domain masking and is functional as an oligomer. Nat Struct Mol Biol 2015; 22:540-6. [PMID: 26052892 PMCID: PMC4496297 DOI: 10.1038/nsmb.3044] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 05/12/2015] [Indexed: 12/21/2022]
Abstract
The chaperone-usher (CU) pathway assembles organelles termed pili or
fimbriae in Gram-negative bacteria. Type 1 pili expressed by uropathogenic
Escherichia coli are prototypical structures assembled by
the CU pathway. Biogenesis of pili by the CU pathway requires a periplasmic
chaperone and an outer membrane protein termed the usher (FimD). We show that
the FimD C-terminal domains provide the high-affinity substrate binding site,
but that these domains are masked in the resting usher. Domain masking requires
the FimD plug domain, which serves as a switch controlling usher activation. We
demonstrate that usher molecules can act in trans for pilus
biogenesis, providing conclusive evidence for a functional usher oligomer. These
results reveal mechanisms by which molecular machines such as the usher regulate
and harness protein-protein interactions, and suggest that ushers may interact
in a cooperative manner during pilus assembly in bacteria.
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7
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Allosteric Mechanism Controls Traffic in the Chaperone/Usher Pathway. Structure 2012; 20:1861-71. [PMID: 22981947 DOI: 10.1016/j.str.2012.08.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 08/01/2012] [Accepted: 08/13/2012] [Indexed: 11/21/2022]
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Allen WJ, Phan G, Waksman G. Pilus biogenesis at the outer membrane of Gram-negative bacterial pathogens. Curr Opin Struct Biol 2012; 22:500-6. [PMID: 22402496 DOI: 10.1016/j.sbi.2012.02.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 11/24/2022]
Abstract
Pili belong to a broad class of bacterial surface structures that play a key role in infection and pathogenicity. The largest and best characterised pilus biogenesis system--the chaperone-usher pathway--is particularly remarkable in its ability to synthesise and display highly organised structures at the outer membrane without any input from endogenous energy sources. The past few years have heralded exciting new developments in our understanding of the structural biology and mechanism of pilus assembly, which are discussed in this review. Such knowledge will be particularly important in the future, as we approach an era of widespread resistance to common antibiotics and require new targets.
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Affiliation(s)
- William J Allen
- Institute of Structural and Molecular Biology, University College London and Birkbeck, Malet Street, WC1E 7HX London, UK
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9
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Structural insights into the biogenesis and biofilm formation by the Escherichia coli common pilus. Proc Natl Acad Sci U S A 2012; 109:3950-5. [PMID: 22355107 DOI: 10.1073/pnas.1106733109] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteria have evolved a variety of mechanisms for developing community-based biofilms. These bacterial aggregates are of clinical importance, as they are a major source of recurrent disease. Bacterial surface fibers (pili) permit adherence to biotic and abiotic substrates, often in a highly specific manner. The Escherichia coli common pilus (ECP) represents a remarkable family of extracellular fibers that are associated with both disease-causing and commensal strains. ECP plays a dual role in early-stage biofilm development and host cell recognition. Despite being the most common fimbrial structure, relatively little is known regarding its biogenesis, architecture, and function. Here we report atomic-resolution insight into the biogenesis and architecture of ECP. We also derive a structural model for entwined ECP fibers that not only illuminates interbacteria communication during biofilm formation but also provides a useful foundation for the design of novel nanofibers.
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