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Nature Microbiology Nov 2021
Topics: Fimbriae Proteins; Fimbriae, Bacterial; Nanowires
PubMed: 34650249
DOI: 10.1038/s41564-021-00990-0 -
Molecular Microbiology Feb 2018Archaea are ubiquitously present in nature and colonize environments with broadly varying growth conditions. Several surface appendages support their colonization of new... (Review)
Review
Archaea are ubiquitously present in nature and colonize environments with broadly varying growth conditions. Several surface appendages support their colonization of new habitats. A hallmark of archaea seems to be the high abundance of type IV pili (T4P). However, some unique non T4 filaments are present in a number of archaeal species. Archaeal surface structures can mediate different processes such as cellular surface adhesion, DNA exchange, motility and biofilm formation and represent an initial attachment site for infecting viruses. In addition to the functionally characterized archaeal T4P, archaeal genomes encode a large number of T4P components that might form yet undiscovered surface structures with novel functions. In this review, we summarize recent advancement in structural and functional characterizations of known archaeal surface structures and highlight the diverse processes in which they play a role.
Topics: Archaea; Bacterial Adhesion; Biofilms; Fimbriae, Bacterial; Membrane Proteins; Pili, Sex
PubMed: 29194812
DOI: 10.1111/mmi.13889 -
Progress in Biophysics and Molecular... Aug 2017Two fundamental structures in molecular biology, DNA and the α-helix, were determined using X-ray fibre diffraction data, and yet fibre diffraction occupies an obscure... (Review)
Review
Two fundamental structures in molecular biology, DNA and the α-helix, were determined using X-ray fibre diffraction data, and yet fibre diffraction occupies an obscure niche in structural biology. Relatively few structures are appropriate for the technique, and it seldom supplies data of the quality common in protein crystallography; however, it has proven indispensable in some cases. Here we outline some aspects of helix diffraction mathematics, and then illustrate the application of fibre diffraction by three case studies: DNA, filamentous bacterial viruses, and bacterial pili. These examples are illustrative, not exhaustive, and reviews of other important structures such as plant viruses, polysaccharides and amyloids are also cited, as appropriate. Finally we describe in more detail the methods currently used to obtain and analyze fibre diffraction patterns of biological macromolecules, to give a technique-oriented tutorial which may be useful to researchers who find that they require fibre diffraction for their work.
Topics: Animals; Bacteriophages; DNA; Fimbriae, Bacterial; Neutron Diffraction; X-Ray Diffraction
PubMed: 28442432
DOI: 10.1016/j.pbiomolbio.2017.04.005 -
Journal of Industrial Microbiology &... Oct 2020Type IV pili (T4P) are bacterial appendages used for cell adhesion and surface motility. In metal-reducing bacteria in the genus Geobacter, they have the unique property... (Review)
Review
Type IV pili (T4P) are bacterial appendages used for cell adhesion and surface motility. In metal-reducing bacteria in the genus Geobacter, they have the unique property of being conductive and essential to wire cells to extracellular electron acceptors and other cells within biofilms. These electroactive bacteria use a conserved pathway for biological assembly and disassembly of a short and aromatic dense peptide subunit (pilin). The polymerization of the pilins clusters aromatic residues optimally for charge transport and exposes ligands for metal immobilization and reduction. The simple design yet unique functionalities of conductive T4P afford opportunities for the scaled-up production of recombinant pilins and their in vitro assembly into electronic biomaterials of biotechnological interest. This review summarizes current knowledge of conductive T4P biogenesis and functions critical to actualize applications in bioelectronics, bioremediation, and nanotechnology.
Topics: Biofilms; Biology; Biotechnology; Electric Conductivity; Fimbriae Proteins; Fimbriae, Bacterial; Geobacter; Metals; Nanowires; Peptides
PubMed: 33009965
DOI: 10.1007/s10295-020-02312-5 -
Microbiology and Immunology Oct 2020Pili or fimbriae, which are filamentous structures present on the surface of bacteria, were purified from a periodontal pathogen, Porphyromonas gingivalis, in 1980s. The... (Review)
Review
Pili or fimbriae, which are filamentous structures present on the surface of bacteria, were purified from a periodontal pathogen, Porphyromonas gingivalis, in 1980s. The protein component of pili (stalk pilin), which is its major component, was named FimA; it has a molecular weight of approximately 41 kDa. Because the molecular weight of the pilin from P. gingivalis is twice that of pilins from other bacterial pili, the P. gingivalis Fim pili were suggested to be formed via a novel mechanism. In earlier studies, we reported that the FimA pilin is secreted on the cell surface as a lipoprotein precursor, and the subsequent N-terminal processing of the FimA precursor by arginine-specific proteases is necessary for Fim pili formation. The crystal structures of FimA and its related proteins were determined recently, which show that Fim pili are formed by a protease-mediated strand-exchange mechanism. The most recent study conducted by us, wherein we performed cryoelectron microscopy of the pilus structure, provided evidence in support of this mechanism. As the P. gingivalis Fim pili are formed through novel transport and assembly mechanisms, such pili are now designated as Type V pili. Surface lipoproteins, including the anchor pilin FimB of Fim pili that are present on the outer membrane, have been detected in certain Gram-negative bacteria. Here, we describe the assembly mechanisms of pili, including those of Type V and other pili, as well as the lipoprotein transport mechanisms.
Topics: Crystallography, X-Ray; Fimbriae Proteins; Fimbriae, Bacterial; Lipoproteins; Periodontitis; Porphyromonas gingivalis; Protein Conformation; Protein Transport
PubMed: 32816331
DOI: 10.1111/1348-0421.12838 -
International Journal of Molecular... Jul 2017One of the more conspicuous structural features that punctuate the outer cell surface of certain bacterial Gram-positive genera and species is the sortase-dependent... (Review)
Review
One of the more conspicuous structural features that punctuate the outer cell surface of certain bacterial Gram-positive genera and species is the sortase-dependent pilus. As these adhesive and variable-length protrusions jut outward from the cell, they provide a physically expedient and useful means for the initial contact between a bacterium and its ecological milieu. The sortase-dependent pilus displays an elongated macromolecular architecture consisting of two to three types of monomeric protein subunits (pilins), each with their own specific function and location, and that are joined together covalently by the transpeptidyl activity of a pilus-specific C-type sortase enzyme. Sortase-dependent pili were first detected among the Gram-positive pathogens and subsequently categorized as an essential virulence factor for host colonization and tissue invasion by these harmful bacteria. However, the sortase-dependent pilus was rebranded as also a niche-adaptation factor after it was revealed that "friendly" Gram-positive commensals exhibit the same kind of pilus structures, which includes two contrasting gut-adapted species from the genus, allochthonous and autochthonous . This review will highlight and discuss what has been learned from the latest research carried out and published on these lactobacillar pilus types.
Topics: Aminoacyltransferases; Bacterial Proteins; Cysteine Endopeptidases; Fimbriae, Bacterial; Lactobacillus; Models, Molecular
PubMed: 28718795
DOI: 10.3390/ijms18071551 -
Sub-cellular Biochemistry 2019To interact with the external environments, bacteria often display long proteinaceous appendages on their cell surface, called pili or fimbriae. These non-flagellar... (Review)
Review
To interact with the external environments, bacteria often display long proteinaceous appendages on their cell surface, called pili or fimbriae. These non-flagellar thread-like structures are polymers composed of covalently or non-covalently interacting repeated pilin subunits. Distinct pilus classes can be identified on basis of their assembly pathways, including chaperone-usher pili, type V pili, type IV pili, curli and fap fibers, conjugative and type IV secretion pili, as well as sortase-mediated pili. Pili play versatile roles in bacterial physiology, and can be involved in adhesion and host cell invasion, DNA and protein secretion and uptake, biofilm formation, cell motility and more. Recent advances in structure determination of components involved in the various pilus systems has enabled a better molecular understanding of their mechanisms of assembly and function. In this chapter we describe the diversity in structure, biogenesis and function of the different pilus systems found in Gram-positive and Gram-negative bacteria, and review their potential as anti-microbial targets.
Topics: Anti-Bacterial Agents; Fimbriae Proteins; Fimbriae, Bacterial; Gram-Negative Bacteria; Gram-Positive Bacteria
PubMed: 31214993
DOI: 10.1007/978-3-030-18768-2_12 -
Current Topics in Microbiology and... 2017Pili of Gram-positive bacteria are unique structures on the bacterial surface, assembled from covalently linked polypeptide subunits. Pilus assembly proceeds by... (Review)
Review
Pili of Gram-positive bacteria are unique structures on the bacterial surface, assembled from covalently linked polypeptide subunits. Pilus assembly proceeds by transpeptidation reactions catalyzed by sortases, followed by covalent anchoring of the filament in the peptidoglycan layer. Another distinctive property is the presence of intramolecular isopeptide bonds, conferring extraordinary chemical and mechanical stability to these elongated structures. Besides their function in cell adhesion and biofilm formation, this section discusses possible application of pilus constituents as vaccine components against Gram-positive pathogens.
Topics: Bacterial Adhesion; Bacterial Vaccines; Biofilms; Fimbriae, Bacterial; Gram-Positive Bacteria
PubMed: 26847355
DOI: 10.1007/82_2015_5016 -
Protein Science : a Publication of the... Aug 2017Successful adherence, colonization, and survival of Gram-positive bacteria require surface proteins, and multiprotein assemblies called pili. These surface appendages... (Review)
Review
Successful adherence, colonization, and survival of Gram-positive bacteria require surface proteins, and multiprotein assemblies called pili. These surface appendages are attractive pharmacotherapeutic targets and understanding their assembly mechanisms is essential for identifying a new class of 'anti-infectives' that do not elicit microbial resistance. Molecular details of the Gram-negative pilus assembly are available indepth, but the Gram-positive pilus biogenesis is still an emerging field and investigations continue to reveal novel insights into this process. Pilus biogenesis in Gram-positive bacteria is a biphasic process that requires enzymes called pilus-sortases for assembly and a housekeeping sortase for covalent attachment of the assembled pilus to the peptidoglycan cell wall. Emerging structural and functional data indicate that there are at least two groups of Gram-positive pili, which require either the Class C sortase or Class B sortase in conjunction with LepA/SipA protein for major pilin polymerization. This observation suggests two distinct modes of sortase-mediated pilus biogenesis in Gram-positive bacteria. Here we review the structural and functional biology of the pilus-sortases from select streptococcal pilus systems and their role in Gram-positive pilus assembly.
Topics: Aminoacyltransferases; Bacterial Proteins; Cell Wall; Corynebacterium; Cysteine Endopeptidases; Fimbriae Proteins; Fimbriae, Bacterial; Gene Expression Regulation, Bacterial; Models, Molecular; Multigene Family; Peptidoglycan; Protein Domains; Protein Folding; Protein Structure, Secondary; Streptococcus
PubMed: 28493331
DOI: 10.1002/pro.3191 -
Nature Communications Nov 2023Adhesive type 1 pili from uropathogenic Escherichia coli strains are filamentous, supramolecular protein complexes consisting of a short tip fibrillum and a long,...
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.
Topics: Fimbriae, Bacterial; Escherichia coli Proteins; Fimbriae Proteins; Escherichia coli; Molecular Chaperones
PubMed: 38001074
DOI: 10.1038/s41467-023-43449-y