scholarly journals DNA-uptake pilus ofVibrio choleraecapable of kin-discriminated auto-aggregation

2018 ◽  
Author(s):  
David. W. Adams ◽  
Sandrine Stutzmann ◽  
Candice Stoudmann ◽  
Melanie Blokesch
Keyword(s):  
Kin Recognition ◽  
Natural Habitat ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Environmental Isolates ◽  
Dense Networks ◽  
Type Iv ◽  
Pilin Subunit ◽  
Direct Labelling ◽  
Pandemic Strains

AbstractNatural competence for transformation is a widely used and key mode of horizontal gene transfer that can foster rapid bacterial evolution. Competent bacteria take-up DNA from their environment using Type IV pili, a widespread and multi-purpose class of cell surface polymers. However, how pili facilitate DNA-uptake has remained unclear. Here, using direct labelling, we show that in the Gram-negative pathogenVibrio choleraeDNA-uptake pili are highly dynamic and that they retract prior to DNA-uptake. Unexpectedly, these pili can self-interact to mediate auto-aggregation of cells into macroscopic structures. This phenotype is conserved in disease causing pandemic strains. However, extensive strain-to-strain variability in the major pilin subunit PilA, present in environmental isolates, controls the ability of pili to interact without affecting transformation. We go on to show that interactions between pili are highly specific, enabling cells producing pili composed of different PilA subunits to discriminate between one another. On chitin surfaces, a natural habitat ofV. cholerae, pili connect cells within dense networks, suggesting a model whereby DNA-uptake pili function to promote inter-bacterial interactions during surface colonisation. Moreover, our results provide evidence that type IV pili could provide a simple and potentially widespread mechanism for bacterial kin recognition.

scholarly journals The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

2020 ◽  
Vol 295 (19) ◽  
pp. 6594-6604 ◽  
Author(s):  
Devon Sheppard ◽  
Jamie-Lee Berry ◽  
Rémi Denise ◽  
Eduardo P. C. Rocha ◽  
Steve Matthews ◽  
...  
Keyword(s):  
Natural Transformation ◽  
Dna Uptake ◽  
Human Pathogens ◽  
Unusual Structure ◽  
Widespread Distribution ◽  
Solution Structures ◽  
Type Iv ◽  
Filament Assembly ◽  
Pilin Subunit ◽  
Type Iv Pilin

Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

scholarly journals Type IV competence pili in Streptococcus pneumoniae are highly dynamic structures that retract to promote DNA uptake

2021 ◽  
Author(s):  
Trinh Lam ◽  
Courtney K. Ellison ◽  
Ankur B. Dalia ◽  
David T. Eddington ◽  
Donald A. Morrison
Keyword(s):  
Cell Surface ◽  
Active Role ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Gram Positive ◽  
Dynamic Activity ◽  
Positive Type ◽  
Type Iv ◽  
Labeling Approach ◽  
Dynamic Structures

SUMMARYThe competence pili of transformable Gram-positive species form a subset of the diverse and widespread class of extracellular filamentous organelles known as type IV pili (T4P). In Gram-negative bacteria, T4P act through dynamic cycles of extension and retraction to carry out diverse activities including attachment, motility, protein secretion, and DNA uptake. It remains unclear whether T4P in Gram-positive species exhibit this same dynamic activity, and their mechanism of action for DNA uptake remains unclear. They are hypothesized to either (1) passively form transient cavities in the cell wall to facilitate DNA passage, (2) act as static adhesins to enrich DNA near the cell surface for subsequent uptake by membrane-embedded transporters, or (3) play an active role in translocating bound DNA via their dynamic activity. Here, using a recently described pilus labeling approach, we demonstrate that pneumococcal competence pili are highly dynamic structures that rapidly extend and retract from the cell surface. By labeling ComGC with bulky adducts, we further demonstrate that pilus retraction is essential for natural transformation. Together, our results indicate that Gram-positive type IV competence pili are dynamic and retractile structures that play an active role in DNA uptake.Short summaryCompetent pneumococci kill non-competent cells on contact. Retractable DNA-binding fibers in the class of type IV pili may provide a key tool for retrieving DNA segments from cell wreckage for internalization and recombination.

scholarly journals The competence gene, comF, from Synechocystis sp. strain PCC 6803 is involved in natural transformation, phototactic motility and piliation

Microbiology ◽  
2006 ◽  
Vol 152 (12) ◽  
pp. 3623-3631 ◽  
Author(s):  
Kenlee Nakasugi ◽  
Charles J. Svenson ◽  
Brett A. Neilan
Keyword(s):  
Natural Transformation ◽  
Heterotrophic Bacteria ◽  
Fold Increase ◽  
Hypothetical Protein ◽  
Type Iv Pili ◽  
Spectrometric Analysis ◽  
Dna Uptake ◽  
Wild Type ◽  
Type Iv ◽  
Pcc 6803

The gene slr0388 was previously annotated to encode a hypothetical protein in Synechocystis sp. strain PCC 6803. When a positively phototactic strain of this cyanobacterium was insertionally inactivated at slr0388, the mutants were not transformable, and appeared to aggregate as a result of increased bundling of type IV pili. Also, these mutants were rendered non-phototactic compared to the wild-type. Quantitative real-time PCR revealed a 3.5-fold increase in pilA1 transcript levels in the mutant over wild-type cells, while there were no changes in the level of pilT1 and comA transcripts. Supernatant from mutant liquid culture contained more PilA1 protein, confirmed by mass spectrometric analysis, compared to the wild-type cells, which corresponded to the increase in pilA1 transcripts. The increase in PilA1 subunits may contribute to the bundling morphology of pili that was observed, which in turn may act to retard DNA uptake by hindering the retraction of pili. This gene is therefore proposed to be designated comF, as it possesses a phosphoribosyltransferase domain, a distinguishing feature of other ComF proteins of naturally transformable heterotrophic bacteria. This report is the second of a competence-related gene from Synechocystis sp. strain PCC 6803, the product of which does not show homology to other well-studied type IV pili proteins.

scholarly journals Acinetobacter baylyi regulates type IV pilus synthesis by employing two extension motors and a motor protein inhibitor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Courtney K. Ellison ◽  
Triana N. Dalia ◽  
Catherine A. Klancher ◽  
Joshua W. Shaevitz ◽  
Zemer Gitai ◽  
...  
Keyword(s):  
Bacterial Species ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Twitching Motility ◽  
Protein Inhibitor ◽  
Acinetobacter Baylyi ◽  
Type Iv ◽  
Surface Sensing ◽  
Virulence Protein ◽  
Labeling Method

AbstractBacteria use extracellular appendages called type IV pili (T4P) for diverse behaviors including DNA uptake, surface sensing, virulence, protein secretion, and twitching motility. Dynamic extension and retraction of T4P is essential for their function, and T4P extension is thought to occur through the action of a single, highly conserved motor, PilB. Here, we develop Acinetobacter baylyi as a model to study T4P by employing a recently developed pilus labeling method. By contrast to previous studies of other bacterial species, we find that T4P synthesis in A. baylyi is dependent not only on PilB but also on an additional, phylogenetically distinct motor, TfpB. Furthermore, we identify a protein (CpiA) that inhibits T4P extension by specifically binding and inhibiting PilB but not TfpB. These results expand our understanding of T4P regulation and highlight how inhibitors might be exploited to disrupt T4P synthesis.

scholarly journals Pseudomonas aeruginosa Type IV Pilus Expression in Neisseria gonorrhoeae: Effects of Pilin Subunit Composition on Function and Organelle Dynamics

2007 ◽  
Vol 189 (18) ◽  
pp. 6676-6685 ◽  
Author(s):  
Hanne C. Winther-Larsen ◽  
Matthew C. Wolfgang ◽  
Jos P. M. van Putten ◽  
Norbert Roos ◽  
Finn Erik Aas ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Neisseria Gonorrhoeae ◽  
Type Iv Pili ◽  
Type Iv ◽  
Pilin Subunit ◽  
Steady State Levels ◽  
Natural Genetic Transformation ◽  
Necessary And Sufficient ◽  
Pilin Protein ◽  
Behavior Sensitivity

ABSTRACT Type IV pili (TFP) play central roles in the expression of many phenotypes including motility, multicellular behavior, sensitivity to bacteriophages, natural genetic transformation, and adherence. In Neisseria gonorrhoeae, these properties require ancillary proteins that act in conjunction with TFP expression and influence organelle dynamics. Here, the intrinsic contributions of the pilin protein itself to TFP dynamics and associated phenotypes were examined by expressing the Pseudomonas aeruginosa PilAPAK pilin subunit in N. gonorrhoeae. We show here that, although PilAPAK pilin can be readily assembled into TFP in this background, steady-state levels of purifiable fibers are dramatically reduced relative those of endogenous pili. This defect is due to aberrant TFP dynamics as it is suppressed in the absence of the PilT pilus retraction ATPase. Functionally, PilAPAK pilin complements gonococcal adherence for human epithelial cells but only in a pilT background, and this property remains dependent on the coexpression of both the PilC adhesin and the PilV pilin-like protein. Since P. aeruginosa pilin only moderately supports neisserial sequence-specific transformation despite its assembly proficiency, these results together suggest that PilAPAK pilin functions suboptimally in this environment. This appears to be due to diminished compatibility with resident proteins essential for TFP function and dynamics. Despite this, PilAPAK pili support retractile force generation in this background equivalent to that reported for endogenous pili. Furthermore, PilAPAK pili are both necessary and sufficient for bacteriophage PO4 binding, although the strain remains phage resistant. Together, these findings have significant implications for TFP biology in both N. gonorrhoeae and P. aeruginosa.

scholarly journals A new twist on bacterial motility – two distinct type IV pili revealed by cryoEM

2019 ◽  
Author(s):  
Alexander Neuhaus ◽  
Muniyandi Selvaraj ◽  
Ralf Salzer ◽  
Julian D. Langer ◽  
Kerstin Kruse ◽  
...  
Keyword(s):  
Natural Transformation ◽  
Thermus Thermophilus ◽  
Distinct Type ◽  
Type Iv Pili ◽  
Dna Uptake ◽  
Molecular Architecture ◽  
Surface Adhesion ◽  
Cellular Functions ◽  
Type Iv ◽  
New Type

SummaryMany bacteria express flexible protein filaments on their surface that enable a variety of important cellular functions. Type IV pili are examples of such filaments and are comprised of a helical assembly of repeating pilin subunits. Type IV pili are involved in motility (twitching), surface adhesion, biofilm formation and DNA uptake (natural transformation). They are therefore powerful structures that enable bacterial proliferation and genetic adaptation, potentially leading to the development of pathogenicity and antibiotic resistance. They are also targets for drug development.By a complement of experimental approaches, we show that the bacterium Thermus thermophilus produces two different forms of type IV pilus. We have determined the structures of both and built atomic models. The structures answer key unresolved questions regarding the molecular architecture of type IV pili and identify a new type of pilin. We also delineate the roles of the two filaments in promoting twitching and natural transformation.

scholarly journals Direct Extracellular Electron Transfer of the Geobacter sulfurreducens Pili Relevant to Interaromatic Distances

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Chuanjun Shu ◽  
Qiang Zhu ◽  
Ke Xiao ◽  
Yue Hou ◽  
Haibo Ma ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Type Iv Pili ◽  
Geobacter Sulfurreducens ◽  
Transfer Reactions ◽  
Extracellular Electron Transfer ◽  
Aromatic Residues ◽  
New Class ◽  
Type Iv ◽  
Pilin Subunit ◽  
Potential Applications

Microorganisms can transfer electrons directly to extracellular acceptors, during which organic compounds are oxidized to carbon dioxide. One of these microbes, Geobacter sulfurreducens, is well known for the “metallic-like” conductivity of its type IV pili. However, there is no consensus on what the mechanism for electron transfer along these conductive pili is. Based on the aromatic distances and orientations of our predicted models, the mechanism of electron transfer in the Geobacter sulfurreducens (GS) pili was explored by quantum chemical calculations with Marcus theory of electron transfer reactions. Three aromatic residues from the N-terminal α-helix of the GS pilin subunit are packed together, resulting in a continuous pi-pi interaction chain. The theoretical conductance (4.69 μS/3.85 μS) of the predicted models is very similar to that in the experiments reported recently (3.40 μS). These findings offer a new concept that the GS pili belongs to a new class of proteins that can transport electrons through pi-pi interaction between aromatic residues and also provide a valuable tool for guiding further researches of these conductive pili, to investigate their roles in biogeochemical cycling, and potential applications in biomaterials, bioelectronics, and bioenergy.

scholarly journals Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Edoardo D'Imprima ◽  
Ralf Salzer ◽  
Ramachandra M Bhaskara ◽  
Ricardo Sánchez ◽  
Ilona Rose ◽  
...  
Keyword(s):  
Outer Membrane ◽  
Natural Transformation ◽  
Thermus Thermophilus ◽  
Homology Model ◽  
Type Iv Pili ◽  
Gram Negative Bacteria ◽  
Dna Uptake ◽  
Type Iv ◽  
Periplasmic Domain

Secretins form multimeric channels across the outer membrane of Gram-negative bacteria that mediate the import or export of substrates and/or extrusion of type IV pili. The secretin complex of Thermus thermophilus is an oligomer of the 757-residue PilQ protein, essential for DNA uptake and pilus extrusion. Here, we present the cryo-EM structure of this bifunctional complex at a resolution of ~7 Å using a new reconstruction protocol. Thirteen protomers form a large periplasmic domain of six stacked rings and a secretin domain in the outer membrane. A homology model of the PilQ protein was fitted into the cryo-EM map. A crown-like structure outside the outer membrane capping the secretin was found not to be part of PilQ. Mutations in the secretin domain disrupted the crown and abolished DNA uptake, suggesting a central role of the crown in natural transformation.

scholarly journals The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold

2020 ◽  
Author(s):  
Devon Sheppard ◽  
Jamie-Lee Berry ◽  
Rémi Denise ◽  
Eduardo P. C. Rocha ◽  
Steve Matthews ◽  
...  
Keyword(s):  
Natural Transformation ◽  
Homology Modelling ◽  
Dna Uptake ◽  
Human Pathogens ◽  
Unusual Structure ◽  
Solution Structures ◽  
Type Iv ◽  
Filament Assembly ◽  
Pilin Subunit ◽  
Type Iv Pilin

AbstractType IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modelling analyses suggest that ComGC unusual structure is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.

scholarly journals Peptidoglycan-binding protein TsaP functions in surface assembly of type IV pili

2014 ◽  
Vol 111 (10) ◽  
pp. E953-E961 ◽  
Author(s):  
Katja Siewering ◽  
Samta Jain ◽  
Carmen Friedrich ◽  
Mariam T. Webber-Birungi ◽  
Dmitry A. Semchonok ◽  
...  
Keyword(s):  
Type Iv Pili ◽  
Host Cells ◽  
Gram Negative Bacteria ◽  
Dependent Manner ◽  
Dna Uptake ◽  
Oligomeric State ◽  
Gram Negative ◽  
Type Iv ◽  
Surface Assembly ◽  
Peripheral Structure

Type IV pili (T4P) are ubiquitous and versatile bacterial cell surface structures involved in adhesion to host cells, biofilm formation, motility, and DNA uptake. In Gram-negative bacteria, T4P pass the outer membrane (OM) through the large, oligomeric, ring-shaped secretin complex. In the β-proteobacteriumNeisseria gonorrhoeae, the native PilQ secretin ring embedded in OM sheets is surrounded by an additional peripheral structure, consisting of a peripheral ring and seven extending spikes. To unravel proteins important for formation of this additional structure, we identified proteins that are present with PilQ in the OM. One such protein, which we name T4P secretin-associated protein (TsaP), was identified as a phylogenetically widely conserved component of the secretin complex that co-occurs with genes for T4P in Gram-negative bacteria. TsaP contains an N-terminal carbohydrate-binding lysin motif (LysM) domain and a C-terminal domain of unknown function. InN. gonorrhoeae, lack of TsaP results in the formation of membrane protrusions containing multiple T4P, concomitant with reduced formation of surface-exposed T4P. Lack of TsaP did not affect the oligomeric state of PilQ, but resulted in loss of the peripheral structure around the PilQ secretin. TsaP binds peptidoglycan and associates strongly with the OM in a PilQ-dependent manner. In the δ-proteobacteriumMyxococcus xanthus, TsaP is also important for surface assembly of T4P, and it accumulates and localizes in a PilQ-dependent manner to the cell poles. Our results show that TsaP is a novel protein associated with T4P function and suggest that TsaP functions to anchor the secretin complex to the peptidoglycan.

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