1
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Zyla DS, Wiegand T, Bachmann P, Zdanowicz R, Giese C, Meier BH, Waksman G, Hospenthal MK, Glockshuber R. The assembly platform FimD is required to obtain the most stable quaternary structure of type 1 pili. Nat Commun 2024; 15:3032. [PMID: 38589417 PMCID: PMC11001860 DOI: 10.1038/s41467-024-47212-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 03/22/2024] [Indexed: 04/10/2024] Open
Abstract
Type 1 pili are important virulence factors of uropathogenic Escherichia coli that mediate bacterial attachment to epithelial cells in the urinary tract. The pilus rod is comprised of thousands of copies of the main structural subunit FimA and is assembled in vivo by the assembly platform FimD. Although type 1 pilus rods can self-assemble from FimA in vitro, this reaction is slower and produces structures with lower kinetic stability against denaturants compared to in vivo-assembled rods. Our study reveals that FimD-catalysed in vitro-assembled type 1 pilus rods attain a similar stability as pilus rods assembled in vivo. Employing structural, biophysical and biochemical analyses, we show that in vitro assembly reactions lacking FimD produce pilus rods with structural defects, reducing their stability against dissociation. Overall, our results indicate that FimD is not only required for the catalysis of pilus assembly, but also to control the assembly of the most stable quaternary structure.
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Affiliation(s)
- Dawid S Zyla
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
- La Jolla Institute for Immunology, 9420 Athena Cir, La Jolla, CA, 92037, USA
| | - Thomas Wiegand
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074, Aachen, Germany
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470, Mülheim/Ruhr, Germany
| | - Paul Bachmann
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
| | - Rafal Zdanowicz
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
| | - Christoph Giese
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
| | - Beat H Meier
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck, London, WC1E 7HX, UK
| | - Manuela K Hospenthal
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland.
- Institute of Structural and Molecular Biology, University College London and Birkbeck, London, WC1E 7HX, UK.
| | - Rudi Glockshuber
- Institute of Molecular Biology and Biophysics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
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2
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Giese C, Puorger C, Ignatov O, Bečárová Z, Weber ME, Schärer MA, Capitani G, Glockshuber R. Stochastic chain termination in bacterial pilus assembly. Nat Commun 2023; 14:7718. [PMID: 38001074 PMCID: PMC10673952 DOI: 10.1038/s41467-023-43449-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Adhesive type 1 pili from uropathogenic Escherichia coli strains are filamentous, supramolecular protein complexes consisting of a short tip fibrillum and a long, helical rod formed by up to several thousand copies of the major pilus subunit FimA. Here, we reconstituted the entire type 1 pilus rod assembly reaction in vitro, using all constituent protein subunits in the presence of the assembly platform FimD, and identified the so-far uncharacterized subunit FimI as an irreversible assembly terminator. We provide a complete, quantitative model of pilus rod assembly kinetics based on the measured rate constants of FimD-catalyzed subunit incorporation. The model reliably predicts the length distribution of assembled pilus rods as a function of the ratio between FimI and the main pilus subunit FimA and is fully consistent with the length distribution of membrane-anchored pili assembled in vivo. The results show that the natural length distribution of adhesive pili formed via the chaperone-usher pathway results from a stochastic chain termination reaction. In addition, we demonstrate that FimI contributes to anchoring the pilus to the outer membrane and report the crystal structures of (i) FimI in complex with the assembly chaperone FimC, (ii) the FimI-FimC complex bound to the N-terminal domain of FimD, and (iii) a ternary complex between FimI, FimA and FimC that provides structural insights on pilus assembly termination and pilus anchoring by FimI.
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Affiliation(s)
- Christoph Giese
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland.
| | - Chasper Puorger
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
- Institute for Chemistry and Bioanalytics, University of Applied Sciences and Arts Northwestern Switzerland, 4132, Muttenz, Switzerland
| | - Oleksandr Ignatov
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
- V.I. Grishchenko Clinic of Reproductive Medicine, Blahovishchenska st.25, 61052, Kharkiv, Ukraine
| | - Zuzana Bečárová
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Marco E Weber
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Martin A Schärer
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Guido Capitani
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232, Villigen, Switzerland
| | - Rudi Glockshuber
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, 8093, Zurich, Switzerland
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3
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Shanmugasundarasamy T, Karaiyagowder Govindarajan D, Kandaswamy K. A review on pilus assembly mechanisms in Gram-positive and Gram-negative bacteria. Cell Surf 2022; 8:100077. [PMID: 35493982 PMCID: PMC9046445 DOI: 10.1016/j.tcsw.2022.100077] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/08/2022] [Accepted: 04/18/2022] [Indexed: 12/17/2022] Open
Abstract
The surface of Gram-positive and Gram-negative bacteria contains long hair-like proteinaceous protrusion known as pili or fimbriae. Historically, pilin proteins were considered to play a major role in the transfer of genetic material during bacterial conjugation. Recent findings however elucidate their importance in virulence, biofilm formation, phage transduction, and motility. Therefore, it is crucial to gain mechanistic insights on the subcellular assembly of pili and the localization patterns of their subunit proteins (major and minor pilins) that aid the macromolecular pilus assembly at the bacterial surface. In this article, we review the current knowledge of pilus assembly mechanisms in a wide range of Gram-positive and Gram-negative bacteria, including subcellular localization patterns of a few pilin subunit proteins and their role in virulence and pathogenesis.
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4
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Abstract
The chaperone-usher (CU) pathway is a conserved secretion system dedicated to the assembly of a superfamily of virulence-associated surface structures by a wide range of Gram-negative bacteria. Pilus biogenesis by the CU pathway requires two specialized assembly components: a dedicated periplasmic chaperone and an integral outer membrane assembly and secretion platform termed the usher. The CU pathway assembles a variety of surface fibers, ranging from thin, flexible filaments to rigid, rod-like organelles. Pili typically act as adhesins and function as virulence factors that mediate contact with host cells and colonization of host tissues. Pilus-mediated adhesion is critical for early stages of infection, allowing bacteria to establish a foothold within the host. Pili are also involved in modulation of host cell signaling pathways, bacterial invasion into host cells, and biofilm formation. Pili are critical for initiating and sustaining infection and thus represent attractive targets for the development of antivirulence therapeutics. Such therapeutics offer a promising alternative to broad-spectrum antibiotics and provide a means to combat antibiotic resistance and treat infection while preserving the beneficial microbiota. A number of strategies have been taken to develop antipilus therapeutics, including vaccines against pilus proteins, competitive inhibitors of pilus-mediated adhesion, and small molecules that disrupt pilus biogenesis. Here we provide an overview of the function and assembly of CU pili and describe current efforts aimed at interfering with these critical virulence structures.
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5
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Handover mechanism of the growing pilus by the bacterial outer-membrane usher FimD. Nature 2018; 562:444-447. [PMID: 30283140 PMCID: PMC6309448 DOI: 10.1038/s41586-018-0587-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 08/15/2018] [Indexed: 12/19/2022]
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6
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Werneburg GT, Thanassi DG. Pili Assembled by the Chaperone/Usher Pathway in Escherichia coli and Salmonella. EcoSal Plus 2018; 8:10.1128/ecosalplus.ESP-0007-2017. [PMID: 29536829 PMCID: PMC5940347 DOI: 10.1128/ecosalplus.esp-0007-2017] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Indexed: 12/12/2022]
Abstract
Gram-negative bacteria assemble a variety of surface structures, including the hair-like organelles known as pili or fimbriae. Pili typically function in adhesion and mediate interactions with various surfaces, with other bacteria, and with other types of cells such as host cells. The chaperone/usher (CU) pathway assembles a widespread class of adhesive and virulence-associated pili. Pilus biogenesis by the CU pathway requires a dedicated periplasmic chaperone and integral outer membrane protein termed the usher, which forms a multifunctional assembly and secretion platform. This review addresses the molecular and biochemical aspects of the CU pathway in detail, focusing on the type 1 and P pili expressed by uropathogenic Escherichia coli as model systems. We provide an overview of representative CU pili expressed by E. coli and Salmonella, and conclude with a discussion of potential approaches to develop antivirulence therapeutics that interfere with pilus assembly or function.
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Affiliation(s)
- Glenn T. Werneburg
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
- Center for Infectious Diseases, Stony Brook University, Stony Brook, NY, USA
| | - David G. Thanassi
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, USA
- Center for Infectious Diseases, Stony Brook University, Stony Brook, NY, USA
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7
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Manteca A, Alonso-Caballero Á, Fertin M, Poly S, De Sancho D, Perez-Jimenez R. The influence of disulfide bonds on the mechanical stability of proteins is context dependent. J Biol Chem 2017. [PMID: 28642368 DOI: 10.1074/jbc.m117.784934] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Disulfide bonds play a crucial role in proteins, modulating their stability and constraining their conformational dynamics. A particularly important case is that of proteins that need to withstand forces arising from their normal biological function and that are often disulfide bonded. However, the influence of disulfides on the overall mechanical stability of proteins is poorly understood. Here, we used single-molecule force spectroscopy (smFS) to study the role of disulfide bonds in different mechanical proteins in terms of their unfolding forces. For this purpose, we chose the pilus protein FimG from Gram-negative bacteria and a disulfide-bonded variant of the I91 human cardiac titin polyprotein. Our results show that disulfide bonds can alter the mechanical stability of proteins in different ways depending on the properties of the system. Specifically, disulfide-bonded FimG undergoes a 30% increase in its mechanical stability compared with its reduced counterpart, whereas the unfolding force of I91 domains experiences a decrease of 15% relative to the WT form. Using a coarse-grained simulation model, we rationalized that the increase in mechanical stability of FimG is due to a shift in the mechanical unfolding pathway. The simple topology-based explanation suggests a neutral effect in the case of titin. In summary, our results indicate that disulfide bonds in proteins act in a context-dependent manner rather than simply as mechanical lockers, underscoring the importance of considering disulfide bonds both computationally and experimentally when studying the mechanical properties of proteins.
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Affiliation(s)
- Aitor Manteca
- From the Nanobiomechanics Laboratory, CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
| | | | - Marie Fertin
- From the Nanobiomechanics Laboratory, CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain
| | - Simon Poly
- the Interfaculty Institute of Biochemistry, University of Tübingen, 72076 Tübingen, Germany, and
| | - David De Sancho
- From the Nanobiomechanics Laboratory, CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain, .,the IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
| | - Raul Perez-Jimenez
- From the Nanobiomechanics Laboratory, CIC nanoGUNE, 20018 Donostia-San Sebastián, Spain, .,the IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain
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8
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Structural and Molecular Biology of a Protein-Polymerizing Nanomachine for Pilus Biogenesis. J Mol Biol 2017; 429:2654-2666. [PMID: 28551336 DOI: 10.1016/j.jmb.2017.05.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 01/23/2023]
Abstract
Bacteria produce protein polymers on their surface called pili or fimbriae that serve either as attachment devices or as conduits for secreted substrates. This review will focus on the chaperone-usher pathway of pilus biogenesis, a widespread assembly line for pilus production at the surface of Gram-negative bacteria and the archetypical protein-polymerizing nanomachine. Comparison with other nanomachines polymerizing other types of biological units, such as nucleotides during DNA replication, provides some unifying principles as to how multidomain proteins assemble biological polymers.
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9
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Ikai R, Hasegawa Y, Izumigawa M, Nagano K, Yoshida Y, Kitai N, Lamont RJ, Yoshimura F, Murakami Y. Mfa4, an Accessory Protein of Mfa1 Fimbriae, Modulates Fimbrial Biogenesis, Cell Auto-Aggregation, and Biofilm Formation in Porphyromonas gingivalis. PLoS One 2015; 10:e0139454. [PMID: 26437277 PMCID: PMC4593637 DOI: 10.1371/journal.pone.0139454] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 09/13/2015] [Indexed: 12/23/2022] Open
Abstract
Porphyromonas gingivalis, a gram-negative obligate anaerobic bacterium, is considered to be a key pathogen in periodontal disease. The bacterium expresses Mfa1 fimbriae, which are composed of polymers of Mfa1. The minor accessory components Mfa3, Mfa4, and Mfa5 are incorporated into these fimbriae. In this study, we characterized Mfa4 using genetically modified strains. Deficiency in the mfa4 gene decreased, but did not eliminate, expression of Mfa1 fimbriae. However, Mfa3 and Mfa5 were not incorporated because of defects in posttranslational processing and leakage into the culture supernatant, respectively. Furthermore, the mfa4-deficient mutant had an increased tendency to auto-aggregate and form biofilms, reminiscent of a mutant completely lacking Mfa1. Notably, complementation of mfa4 restored expression of structurally intact and functional Mfa1 fimbriae. Taken together, these results indicate that the accessory proteins Mfa3, Mfa4, and Mfa5 are necessary for assembly of Mfa1 fimbriae and regulation of auto-aggregation and biofilm formation of P. gingivalis. In addition, we found that Mfa3 and Mfa4 are processed to maturity by the same RgpA/B protease that processes Mfa1 subunits prior to polymerization.
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Affiliation(s)
- Ryota Ikai
- Department of Oral Microbiology, Asahi University School of Dentistry, Mizuho, Gifu, Japan
- Department of Orthodontics, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Yoshiaki Hasegawa
- Department of Oral Microbiology, Asahi University School of Dentistry, Mizuho, Gifu, Japan
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan
- * E-mail:
| | - Masashi Izumigawa
- Department of Oral Microbiology, Asahi University School of Dentistry, Mizuho, Gifu, Japan
- Department of Orthodontics, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Keiji Nagano
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan
| | - Yasuo Yoshida
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan
| | - Noriyuki Kitai
- Department of Orthodontics, Asahi University School of Dentistry, Mizuho, Gifu, Japan
| | - Richard J. Lamont
- Department of Oral Immunology and Infectious Diseases, School of Dentistry, University of Louisville, Louisville, KY, United States of America
| | - Fuminobu Yoshimura
- Department of Microbiology, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi, Japan
| | - Yukitaka Murakami
- Department of Oral Microbiology, Asahi University School of Dentistry, Mizuho, Gifu, Japan
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10
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Chahales P, Thanassi DG. Structure, Function, and Assembly of Adhesive Organelles by Uropathogenic Bacteria. Microbiol Spectr 2015; 3:10.1128/microbiolspec.UTI-0018-2013. [PMID: 26542038 PMCID: PMC4638162 DOI: 10.1128/microbiolspec.uti-0018-2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Indexed: 01/02/2023] Open
Abstract
Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities, including biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hair-like fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections.
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Affiliation(s)
- Peter Chahales
- Center for Infectious Diseases and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794
| | - David G Thanassi
- Center for Infectious Diseases and Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY 11794
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11
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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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12
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Busch A, Phan G, Waksman G. Molecular mechanism of bacterial type 1 and P pili assembly. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2013.0153. [PMID: 25624519 DOI: 10.1098/rsta.2013.0153] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The formation of adhesive surface structures called pili or fimbriae ('bacterial hair') is an important contributor towards bacterial pathogenicity and persistence. To fight often chronic or recurrent bacterial infections such as urinary tract infections, it is necessary to understand the molecular mechanism of the nanomachines assembling such pili. Here, we focus on the so far best-known pilus assembly machinery: the chaperone-usher pathway producing the type 1 and P pili, and highlight the most recently acquired structural knowledge. First, we describe the subunits' structure and the molecular role of the periplasmic chaperone. Second, we focus on the outer-membrane usher structure and the catalytic mechanism of usher-mediated pilus biogenesis. Finally, we describe how the detailed understanding of the chaperone-usher pathway at a molecular level has paved the way for the design of a new generation of bacterial inhibitors called 'pilicides'.
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Affiliation(s)
- Andreas Busch
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Gilles Phan
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology, University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
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13
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Geibel S, Waksman G. The molecular dissection of the chaperone–usher pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1559-67. [DOI: 10.1016/j.bbamcr.2013.09.023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 01/11/2023]
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14
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Lillington J, Geibel S, Waksman G. Reprint of "Biogenesis and adhesion of type 1 and P pili". Biochim Biophys Acta Gen Subj 2014; 1850:554-64. [PMID: 25063559 DOI: 10.1016/j.bbagen.2014.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/22/2014] [Accepted: 04/24/2014] [Indexed: 12/20/2022]
Abstract
BACKGROUND Uropathogenic Escherichia coli (UPEC) cause urinary tract infections (UTIs) in approximately 50% of women. These bacteria use type 1 and P pili for host recognition and attachment. These pili are assembled by the chaperone-usher pathway of pilus biogenesis. SCOPE OF REVIEW The review examines the biogenesis and adhesion of the UPEC type 1 and P pili. Particular emphasis is drawn to the role of the outer membrane usher protein. The structural properties of the complete pilus are also examined to highlight the strength and functionality of the final assembly. MAJOR CONCLUSIONS The usher orchestrates the sequential addition of pilus subunits in a defined order. This process follows a subunit-incorporation cycle which consists of four steps: recruitment at the usher N-terminal domain, donor-strand exchange with the previously assembled subunit, transfer to the usher C-terminal domains and translocation of the nascent pilus. Adhesion by the type 1 and P pili is strengthened by the quaternary structure of their rod sections. The rod is endowed with spring-like properties which provide mechanical resistance against urine flow. The distal adhesins operate differently from one another, targeting receptors in a specific manner. The biogenesis and adhesion of type 1 and P pili are being therapeutically targeted, and efforts to prevent pilus growth or adherence are described. GENERAL SIGNIFICANCE The combination of structural and biochemical study has led to the detailed mechanistic understanding of this membrane spanning nano-machine. This can now be exploited to design novel drugs able to inhibit virulence. This is vital in the present era of resurgent antibiotic resistance. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.
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Affiliation(s)
- James Lillington
- Institute of Structural and Molecular Biology (ISMB), University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Sebastian Geibel
- Institute of Structural and Molecular Biology (ISMB), University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology (ISMB), University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK.
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15
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Lillington J, Geibel S, Waksman G. Biogenesis and adhesion of type 1 and P pili. Biochim Biophys Acta Gen Subj 2014; 1840:2783-93. [PMID: 24797039 DOI: 10.1016/j.bbagen.2014.04.021] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 04/22/2014] [Accepted: 04/24/2014] [Indexed: 01/22/2023]
Abstract
BACKGROUND Uropathogenic Escherichia coli (UPEC) cause urinary tract infections (UTIs) in approximately 50% of women. These bacteria use type 1 and P pili for host recognition and attachment. These pili are assembled by the chaperone-usher pathway of pilus biogenesis. SCOPE OF REVIEW The review examines the biogenesis and adhesion of the UPEC type 1 and P pili. Particular emphasis is drawn to the role of the outer membrane usher protein. The structural properties of the complete pilus are also examined to highlight the strength and functionality of the final assembly. MAJOR CONCLUSIONS The usher orchestrates the sequential addition of pilus subunits in a defined order. This process follows a subunit-incorporation cycle which consists of four steps: recruitment at the usher N-terminal domain, donor-strand exchange with the previously assembled subunit, transfer to the usher C-terminal domains and translocation of the nascent pilus. Adhesion by the type 1 and P pili is strengthened by the quaternary structure of their rod sections. The rod is endowed with spring-like properties which provide mechanical resistance against urine flow. The distal adhesins operate differently from one another, targeting receptors in a specific manner. The biogenesis and adhesion of type 1 and P pili are being therapeutically targeted, and efforts to prevent pilus growth or adherence are described. GENERAL SIGNIFICANCE The combination of structural and biochemical study has led to the detailed mechanistic understanding of this membrane spanning nano-machine. This can now be exploited to design novel drugs able to inhibit virulence. This is vital in the present era of resurgent antibiotic resistance. This article is part of a Special Issue entitled Structural biochemistry and biophysics of membrane proteins.
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Affiliation(s)
- James Lillington
- Institute of Structural and Molecular Biology (ISMB), University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Sebastian Geibel
- Institute of Structural and Molecular Biology (ISMB), University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK
| | - Gabriel Waksman
- Institute of Structural and Molecular Biology (ISMB), University College London and Birkbeck College, Malet Street, London WC1E 7HX, UK.
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Molecular basis of usher pore gating in Escherichia coli pilus biogenesis. Proc Natl Acad Sci U S A 2013; 110:20741-6. [PMID: 24297893 DOI: 10.1073/pnas.1320528110] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Extracellular fibers called chaperone-usher pathway pili are critical virulence factors in a wide range of Gram-negative pathogenic bacteria that facilitate binding and invasion into host tissues and mediate biofilm formation. Chaperone-usher pathway ushers, which catalyze pilus assembly, contain five functional domains: a 24-stranded transmembrane β-barrel translocation domain (TD), a β-sandwich plug domain (PLUG), an N-terminal periplasmic domain, and two C-terminal periplasmic domains (CTD1 and 2). Pore gating occurs by a mechanism whereby the PLUG resides stably within the TD pore when the usher is inactive and then upon activation is translocated into the periplasmic space, where it functions in pilus assembly. Using antibiotic sensitivity and electrophysiology experiments, a single salt bridge was shown to function in maintaining the PLUG in the TD channel of the P pilus usher PapC, and a loop between the 12th and 13th beta strands of the TD (β12-13 loop) was found to facilitate pore opening. Mutation of the β12-13 loop resulted in a closed PapC pore, which was unable to efficiently mediate pilus assembly. Deletion of the PapH terminator/anchor resulted in increased OM permeability, suggesting a role for the proper anchoring of pili in retaining OM integrity. Further, we introduced cysteine residues in the PLUG and N-terminal periplasmic domains that resulted in a FimD usher with a greater propensity to exist in an open conformation, resulting in increased OM permeability but no loss in type 1 pilus assembly. These studies provide insights into the molecular basis of usher pore gating and its roles in pilus biogenesis and OM permeability.
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FimY does not interfere with FimZ-FimW interaction during type 1 fimbria production by Salmonella enterica serovar Typhimurium. Infect Immun 2013; 81:4453-60. [PMID: 24042120 DOI: 10.1128/iai.00795-13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The production of type 1 fimbriae in Salmonella enterica serovar Typhimurium is controlled, in part, by three proteins, FimZ, FimY, and FimW. Amino acid sequence analysis indicates that FimZ belongs to the family of bacterial response regulators of two-component systems. In these studies, we have demonstrated that introducing a mutation mimicking phosphorylation of FimZ is necessary for activation of its target gene, fimA. In addition, the interaction of FimZ with FimW, a repressor of fimA expression, occurs only when FimZ is phosphorylated. Consequently, the negative regulatory effect of FimW is most likely due to downmodulation of the active FimZ protein. FimY does not appear to function as a response regulator, and its activity can be lost by mimicking the phosphorylation of FimY. Overproduction of FimY cannot alleviate the nonfimbriate phenotype in a FimZ mutant, whereas high levels of FimZ can overcome the nonfimbriate phenotype of a FimY mutant. It appears that FimY acts upstream of FimZ to activate fimA expression.
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Ordered and ushered; the assembly and translocation of the adhesive type I and p pili. BIOLOGY 2013; 2:841-60. [PMID: 24833049 PMCID: PMC3960871 DOI: 10.3390/biology2030841] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/21/2013] [Accepted: 05/24/2013] [Indexed: 11/17/2022]
Abstract
Type I and P pili are chaperone-usher pili of uropathogenic Escherichia coli, which allow bacteria to adhere to host cell receptors. Pilus formation and secretion are orchestrated by two accessory proteins, a chaperone, which catalyses pilus subunit folding and maintains them in a polymerization-competent state, and an outer membrane-spanning nanomachine, the usher, which choreographs their assembly into a pilus and drives their secretion through the membrane. In this review, recent structures and kinetic studies are combined to examine the mechanism of type I and P pili assembly, as it is currently known. We also investigate how the knowledge of pilus biogenesis mechanisms has been exploited to design selective inhibitors of the process.
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