Analyses of biosynthesis mutants reveal that the fifth and sixth sugars of the Porphyromonas gingivalis O-glycan are L-fucose and N-acetylgalactosamine respectively.

The oral pathogen, Porphyromonas gingivalis has a general O-glycosylation system which it utilises to modify hundreds of proteins localised outside of the cytoplasm. The O-glycan is a heptasaccharide that includes a putative L-fucose and N-acetylgalactosamine (GalNAc) as the 5th and 6th sugar residues respectively. The putative L-fucose is expected to be synthesized as GDP-L-fucose involving the enzymes Gmd (PGN_1078) and Fcl (PGN_1079), while GalNAc is putatively epimerised from GlcNAc by GalE (PGN_1614).

Cell-to-cell interactions revealed by cryo-tomography of a DPANN co-culture system.

DPANN is a widespread and diverse group of archaea characterized by their small size, reduced genome, limited metabolic pathways, and symbiotic existence. Known DPANN species are predominantly obligate ectosymbionts that depend on their host for proliferation. The structural and molecular details of host recognition, host-DPANN intercellular communication, and host adaptation in response to DPANN attachment remain unknown.

Ultrastructural and glycoproteomic characterization of Prevotella intermedia: Insights into O-glycosylation and outer membrane vesicles.

Prevotella intermedia, a Gram-negative bacterium from the Bacteroidota phylum, is associated with periodontitis. Other species within this phylum are known to possess the general O-glycosylation system. The O-glycoproteome has been characterized in several species, including Tannerella forsythia, Porphyromonas gingivalis, and Flavobacterium johnsoniae.

Characterization of the -Glycoproteome of Flavobacterium johnsoniae.

Flavobacterium johnsoniae is a free-living member of the phylum that is found in soil and water. It is frequently used as a model species for studying a type of gliding motility dependent on the type IX secretion system (T9SS). -Glycosylation has been reported in several species, and the -glycosylation of S-layer proteins in Tannerella forsythia was shown to be important for certain virulence features.

Protein interactome mapping of Porphyromonas gingivalis provides insights into the formation of the PorQ-Z complex of the type IX secretion system.

Porphyromonas gingivalis is an anaerobic Gram-negative human oral pathogen highly associated with the more severe forms of periodontal disease. Porphyromonas gingivalis utilises the type IX secretion system (T9SS) to transport ∼30 cargo proteins, including multiple virulence factors, to the cell surface. The T9SS is a multiprotein system consisting of at least 20 proteins, and recently, we characterised the protein interactome of these components.

Type B CTD Proteins Secreted by the Type IX Secretion System Associate with PorP-like Proteins for Cell Surface Anchorage.

The type IX secretion system (T9SS) consists of at least 20 components that translocate proteins with type A or type B C-terminal domain (CTD) signals across the outer membrane (OM). While type A CTD proteins are anchored to the cell surface via covalent linkage to the anionic lipopolysaccharide, it is still unclear how type B CTD proteins are anchored to the cell surface. Moreover, very little is known about the PorE and PorP components of the T9SS.

Protein Interactome Analysis of the Type IX Secretion System Identifies PorW as the Missing Link between the PorK/N Ring Complex and the Sov Translocon.

The type IX secretion system (T9SS) transports cargo proteins through the outer membrane of and attaches them to the cell surface for functions including pathogenesis, gliding motility, and degradation of carbon sources. The T9SS comprises at least 20 different proteins and includes several modules: the trans-envelope core module comprising the PorL/M motor and the PorK/N ring, the outer membrane Sov translocon, and the cell attachment complex. However, the spatial organization of these modules is unknown.

Characterization of the O-Glycoproteome of Porphyromonas gingivalis.

Porphyromonas gingivalis is an important human pathogen and also a model organism for the Bacteroidetes phylum. O-glycosylation has been reported in this phylum with findings that include the O-glycosylation motif, the structure of the O-glycans in a few species, and an extensive O-glycoproteome analysis in Tannerella forsythia. However, O-glycosylation has not yet been confirmed in P.

Characterization of the O-Glycoproteome of Tannerella forsythia.

Tannerella forsythia is a Gram-negative oral pathogen known to possess an O-glycosylation system responsible for targeting multiple proteins associated with virulence at the three-residue motif (D)(S/T)(A/I/L/V/M/T). Multiple proteins have been identified to be decorated with a decasaccharide glycan composed of a poorly defined core plus a partially characterized species-specific section. To date, glycosylation studies have focused mainly on the two S-layer glycoproteins, TfsA and TfsB, so the true extent of glycosylation within this species has not been fully explored.

Complementation in of Porphyromonas gingivalis Lipopolysaccharide Biosynthetic Mutants Demonstrates Lipopolysaccharide Exchange.

, a bacterial pathogen contributing to human periodontitis, exports and anchors cargo proteins to its surface, enabling the production of black pigmentation using a type IX secretion system (T9SS) and conjugation to anionic lipopolysaccharide (A-LPS). To determine whether T9SS components need to be assembled for correct secretion and A-LPS modification of cargo proteins, combinations of nonpigmented mutants lacking A-LPS or a T9SS component were mixed to investigate in complementation. Reacquisition of pigmentation occurred only between an A-LPS mutant and a T9SS mutant, which coincided with A-LPS modification of cargo proteins detected by Western blotting and coimmunoprecipitation/quantitative mass spectrometry.

Towards defining the outer membrane proteome of Porphyromonas gingivalis.

Porphyromonas gingivalis is a Gram-negative anaerobic pathogen found in subgingival plaque associated with progressive periodontitis. Proteins associated with the outer membrane (OM) of Gram-negative pathogens are particularly important for understanding virulence and for developing vaccines. The aim of this study was to establish a reliable list of outer membrane associated proteins (Omps) for this organism.

Type IX Secretion System Cargo Proteins Are Glycosylated at the C Terminus with a Novel Linking Sugar of the Wbp/Vim Pathway.

and use the type IX secretion system to secrete cargo proteins to the cell surface where they are anchored via glycolipids. In , the glycolipid is anionic lipopolysaccharide (A-LPS), of partially known structure. Modified cargo proteins were deglycosylated using trifluoromethanesulfonic acid and digested with trypsin or proteinase K.

Structural Characterization of the Type IX Secretion System in Porphyromonas gingivalis.

The type IX secretion system (T9SS) is the most recently discovered secretion system in the gram-negative bacteria and is specific to the Bacteroidetes phylum. It is comprised of at least 19 proteins, which together allows for the secretion and cell surface attachment of a specific group of proteins (T9SS substrates), that harbor a signal sequence at the C-terminus. Here we describe the structural characterization of the PorK, PorN and PorG components of the Porphyromonas gingivalis T9SS using electron microscopy and cross-linking mass spectrometry.

The Type IX Secretion System: Advances in Structure, Function and Organisation.

The type IX secretion system (T9SS) is specific to the phylum. , a keystone pathogen for periodontitis, utilises the T9SS to transport many proteins-including its gingipain virulence factors-across the outer membrane and attach them to the cell surface. Additionally, the T9SS is also required for gliding motility in motile organisms, such as At least nineteen proteins have been identified as components of the T9SS, including the three transcription regulators, PorX, PorY and SigP.

Quantitative proteomic analysis of the type IX secretion system mutants in Porphyromonas gingivalis.

Porphyromonas gingivalis is an anaerobic, gram-negative human oral pathogen highly associated with chronic periodontitis. P. gingivalis utilizes the type IX secretion system (T9SS) to transport many of its virulence factors including the gingipains to the cell surface.

The Role of Motility in Synergistic Biofilm Formation With .

Chronic periodontitis has a polymicrobial biofilm etiology and interactions between key oral bacterial species, such as and contribute to disease progression. and are co-localized in subgingival plaque and have been previously shown to exhibit strong synergy in growth, biofilm formation and virulence in an animal model of disease. The motility of , although not considered as a classic virulence factor, may be involved in synergistic biofilm development between and .

IL-36γ regulates mediators of tissue homeostasis in epithelial cells.

IL-36 cytokines are critical regulators of mucosal inflammation and homeostasis. IL-36γ regulates the expression of inflammatory cytokines and antimicrobial proteins by gingival epithelial cells (e.g.

Localization of Outer Membrane Proteins in Treponema denticola by Quantitative Proteome Analyses of Outer Membrane Vesicles and Cellular Fractions.

The identification and localization of outer membrane proteins (Omps) and lipoproteins in pathogenic treponemes such as T. denticola (periodontitis) and T. pallidum (syphilis) has been challenging.

Porphyromonas gingivalis Gingipains Display Transpeptidation Activity.

Porphyromonas gingivalis is a keystone periodontal pathogen that has been associated with autoimmune disorders. The cell surface proteases Lys-gingipain (Kgp) and Arg-gingipains (RgpA and RgpB) are major virulence factors, and their proteolytic activity is enhanced by small peptides such as glycylglycine (GlyGly). The reaction kinetics suggested that GlyGly may function as an acceptor molecule for gingipain-catalyzed transpeptidation.

Outer Membrane Vesicle Proteome of Porphyromonas gingivalis Is Differentially Modulated Relative to the Outer Membrane in Response to Heme Availability.

Porphyromonas gingivalis is an anaerobic, Gram-negative oral pathogen associated with chronic periodontitis. P. gingivalis has an obligate requirement for heme, which it obtains from the host.

The Q-Rule: Pyroglutamate in Signal Peptidase I Substrates.

feature prominently in the human microbiome, as major colonizers of the gut and clinically relevant pathogens elsewhere. Here, we reveal a new specific feature in the otherwise widely conserved Sec/SPI (Sec translocase/signal peptidase I) pathway. In , but not the entire FCB group or related phyla, signal peptide cleavage exposes N-terminal glutamine residues in most SPI substrates.

PorV is an Outer Membrane Shuttle Protein for the Type IX Secretion System.

Porphyromonas gingivalis is a keystone pathogen associated with chronic periodontitis. Major virulence factors named gingipains (cysteine proteinases, RgpA, RgpB and Kgp) are secreted via the Type IX Secretion System (T9SS). These, together with approximately 30 other proteins, are secreted to the cell surface and anchored to the outer membrane by covalent modification to anionic lipopolysaccharide (A-LPS) via the novel Gram negative sortase, PorU.

Type IX secretion: the generation of bacterial cell surface coatings involved in virulence, gliding motility and the degradation of complex biopolymers.

The Type IX secretion system (T9SS) is present in over 1000 sequenced species/strains of the Fibrobacteres-Chlorobi-Bacteroidetes superphylum. Proteins secreted by the T9SS have an N-terminal signal peptide for translocation across the inner membrane via the SEC translocon and a C-terminal signal for secretion across the outer membrane via the T9SS. Nineteen protein components of the T9SS have been identified including three, SigP, PorX and PorY that are involved in regulation.

PG1058 Is a Novel Multidomain Protein Component of the Bacterial Type IX Secretion System.

Porphyromonas gingivalis utilises the Bacteroidetes-specific type IX secretion system (T9SS) to export proteins across the outer membrane (OM), including virulence factors such as the gingipains. The secreted proteins have a conserved carboxy-terminal domain essential for type IX secretion that is cleaved upon export. In P.

Structural Insights into the PorK and PorN Components of the Porphyromonas gingivalis Type IX Secretion System.

The type IX secretion system (T9SS) has been recently discovered and is specific to Bacteroidetes species. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilizes the T9SS to transport many proteins including the gingipain virulence factors across the outer membrane and attach them to the cell surface via a sortase-like mechanism. At least 11 proteins have been identified as components of the T9SS including PorK, PorL, PorM, PorN and PorP, however the precise roles of most of these proteins have not been elucidated and the structural organization of these components is unknown.