Tad and toxin-coregulated pilus structures reveal unexpected diversity in bacterial type IV pili

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(49)

Published: Nov. 27, 2023

Type IV pili (T4P) are ubiquitous in both bacteria and archaea. They polymers of the major pilin protein, which has an extended protruding N-terminal helix, α1, a globular C-terminal domain. Cryo-EM structures have revealed key differences between bacterial archaeal T4P their domain structure packing continuity α1. This segment forms continuous α-helix but is partially melted all published due to conserved helix breaking proline at position 22. The tad (tight adhesion) found archaea thought been acquired by through horizontal transfer from Tad pilins unique among T4 pilins, being only 40 60 residues length entirely lacking also lack Pro22 high-resolution structures. We show using cryo-EM that pilus Caulobacter crescentus composed helical subunits that, like portion seen other share arrangement T4P. further T4P, Vibrio cholerae toxin coregulated pilus, lacks not family, α-helix, yet its α1 s arranged similar those Our results highlight role melting support evolutionary relationship

Language: Английский

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High-resolution cryo-EM analysis visualizes hydrated type I and IV pilus structures from enterotoxigenic Escherichia coli

Structure, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Language: Английский

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Unraveling the molecular mechanisms of DNA capture by the Com pilus in naturally transformable monoderm bacteria

mBio, Journal Year: 2025, Volume and Issue: unknown

Published: May 23, 2025

ABSTRACT Transformation is a mechanism of horizontal gene transfer widespread in bacteria. The first step transformation—capture exogenous DNA—is mediated by surface-exposed filaments belonging to the type 4 filament (T4F) superfamily. How these protein polymers, composed major and minor pilin subunits, interact with DNA remains poorly understood. Here, we address this question for Com pilus, T4F mediating capture competent monoderm species. Our functional analysis, performed Streptococcus sanguinis , was guided complete structural model pilus. We show that ComGC does not bind DNA. In contrast, systematic mutational analysis electropositive residues exposed at surface four pilins (ComGD, ComGE, ComGF, ComGG) reveals interface between ComGD ComGF important capture. Sequential mutations two interacting subunits lead abolition transformation, without affecting piliation. further demonstrate physical interaction using disulfide crosslinking, upon mutagenesis strategically positioned into cysteines. A pilus tip recapitulates all findings highlights novel mode DNA-binding, conserved hundreds IMPORTANCE Bacteria are capable evolving diversifying very rapidly acquiring new genetic material via (HGT). HGT, which results from extracellular pili T4F—composed pilins—interact understood, especially species use unique capture, known as or T4dP. significance work characterizing DNA-binding showing pilins, part tip-located complex pilins—found different T4F—has been functionalized monoderms This an evolutionary promoting exceptional versatility T4F.

Language: Английский

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Tad pili with adaptable tips mediate contact-dependent killing during bacterial predation

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: May 13, 2025

Abstract The predatory bacterium, Myxococcus xanthus , kills its prey by contact, using a putative Tight Adherence pilus, known as the Kil system, along with protein complex resembling basal body type-III secretion named “needleless” T3SS*. In this work, we provide direct evidence that polymerizes pilus at contact site, which is constituted major pilin KilP. We also genetically demonstrate predation function of linked to four different minor complexes, work in specific combinations detect and kill phylogenetically diverse bacterial species. Structural models suggest these complexes form interchangeable “Tips”, exposing variable domains extremity interact cells. Remarkably, activity Tips depends on T3SS*, revealing tight functional connection between system While are mostly restricted bacteria, genomic structural analyses other including pathogens, Tad pili customized functionalized similar domains.

Language: Английский

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Architectural dissection of adhesive bacterial cell surface appendages from a “molecular machines” viewpoint

Journal of Bacteriology, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 5, 2024

ABSTRACT The ability of bacteria to interact with and respond their environment is crucial lifestyle survival. Bacterial cells routinely need engage extracellular target molecules, in locations spatially separated from cell surface. Engagement distant targets allows adhere abiotic surfaces host cells, sense harmful or friendly molecules vicinity, as well establish symbiotic interactions neighboring multicellular communities such biofilms. Binding also facilitates transmission information back the originating cell, allowing appropriately external stimuli, which critical throughout bacterial life cycle. This requirement bind fulfilled by a myriad specialized surface often have an extended, filamentous arrangement. In this review, we compare contrast diverse bacteria, fulfil range binding functions for cell. Our comparison shows that even though these extended vastly different sequence, biochemical functional characteristics, they share common architectural principles underpin adhesion variety contexts. light, can consider adhesins under one umbrella, specifically point view modular molecular machine, each part fulfilling distinct role. Such treatise provides opportunity discover fundamental governing sensing, adhesion, biofilm formation.

Language: Английский

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Saccharibacteria deploy two distinct Type IV pili, driving episymbiosis, host competition, and twitching motility

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 25, 2024

Abstract All cultivated Patescibacteria, or CPR, exist as obligate episymbionts on other microbes. Despite being ubiquitous in mammals and environmentally, molecular mechanisms of host identification binding amongst ultrasmall bacterial are largely unknown. Type 4 pili (T4P) well conserved this group predicted to facilitate symbiotic interactions. To test this, we targeted T4P pilin genes Saccharibacteria Nanosynbacter lyticus strain TM7x assess their essentiality roles symbiosis. Our results revealed that N. assembles two distinct T4P, a non-essential thin has the smallest diameter any contributes host-binding, episymbiont growth, competitive fitness relative Saccharibacteria, an essential thick whose functions include twitching motility. Identification lectin-like minor pilins modification cell walls suggest glycan mechanisms. Collectively our findings demonstrate encode unique extracellular vital mediators underexplored episymbiotic lifestyle.

Language: Английский

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