Bent conformation of a backbone pilin N-terminal domain supports a three-stage pilus assembly mechanism

Chaurasia, Priyanka; Pratap, Shivendra; Palva, Airi; Ossowski, Ingemar von; Krishnan, Vengadesan

doi:10.1038/s42003-018-0100-0

Cited by 12 publications

(38 citation statements)

References 65 publications

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“…CppA-SM101 adopts a bent structure, and another type of bent structure was only found in GGSpaD (Chaurasia et al, 2018), as discussed later [ Supplementary Fig. S6(e)].…”

Section: Discussionmentioning

confidence: 80%

“…Recently, structures of GGSpaD have been reported in two crystal systems, and a largely bent structure of GGSpaD was observed in a hexagonal form (PDB entry 5yxo), in which D1 rotated around the hinge region of D1/D2 by 107 compared with the structure in an orthorhombic form [ Supplementary Fig. S6(e); Chaurasia et al, 2018]. The relative orientation and location of D1 and D2/D3 differs from those in CppA-SM101 ( Supplementary Fig.…”

Section: Discussionmentioning

confidence: 99%

“…In GGSpaD, the Lys residue in the pilin motif (Lys180) was exposed on the outside surface of a bent molecule, facilitating nucleophilic attack on the pilin-Srtacyl adduct [ Supplementary Fig. S7(b)], and was proposed to be the active and unliganded form (Chaurasia et al, 2018). Since Lys180 of GGSpaD is located on the opposite side to the cytoplasmic membrane, extensive rearrangements and/or further conformational changes of pilin and SrtC may be needed for Lys180 to form an amide bond to the Thr residue research papers of the CWSS through the polymerization of pili, as suggested in a three-stage model called the expose-ligate-seal mechanism (Chaurasia et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

“…S7(b)], and was proposed to be the active and unliganded form (Chaurasia et al, 2018). Since Lys180 of GGSpaD is located on the opposite side to the cytoplasmic membrane, extensive rearrangements and/or further conformational changes of pilin and SrtC may be needed for Lys180 to form an amide bond to the Thr residue research papers of the CWSS through the polymerization of pili, as suggested in a three-stage model called the expose-ligate-seal mechanism (Chaurasia et al, 2018). On the other hand, Lys174 of CppA-SM101 is located on the inside surface of a bent molecule facing the cytoplasmic membrane [ Supplementary Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The three-dimensional structures of pilins have been very informative for elucidating the pilus fiber structure, the mechanism of Srt-mediated polymerization of pili, and pilimediated infectivity and colonization. X-ray structures of the major pilins from Streptococcus pyrogenes (Spy0128 and T6; Kang et al, 2007;Young et al, 2014), Bacillus cereus (BcpA; Budzik et al, 2009), Corynebacterium diphtheriae (SpaA and SpaD; Kang et al, 2007Kang et al, , 2014, Streptococcus pneumoniae (RrgB and PitB; Paterson & Baker, 2011;El Mortaji et al, 2012;Shaik et al, 2015), Actinomyces oris (FimP;Persson et al, 2015) and Lactobacillus rhamnosus strain GG (GGSpaA and GGSpaD; Chaurasia et al, 2016Chaurasia et al, , 2018 have been reported. They showed that major pilins contain multiple domains with an Ig-like fold with an elongated structure, and that they are arranged in a head-to-tail orientation to form a polymeric structure like a pilus fiber in crystals.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Structures of major pilins inClostridium perfringensdemonstrate dynamic conformational change

Tamai

Katayama

Sekiya

et al. 2019

Acta Cryst Sect D Struct Biol

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Pili in Gram-positive bacteria are flexible rod proteins associated with the bacterial cell surface, and they play important roles in the initial adhesion to host tissues and colonization. The pilus shaft is formed by the covalent polymerization of major pilins, catalyzed by sortases, a family of cysteine transpeptidases.Here, X-ray structures of the major pilins from Clostridium perfringens strains 13 and SM101 and of sortase from strain SM101 are presented with biochemical analysis to detect the formation of pili in vivo. The major pilin from strain 13 adopts an elongated structure to form noncovalently linked polymeric chains in the crystal, yielding a practical model of the pilus fiber structure. The major pilin from strain SM101 adopts a novel bent structure and associates to form a lefthanded twist like an antiparallel double helix in the crystal, which is likely to promote bacterial cell-cell interactions. A modeling study showed that pilin with a bent structure interacts favorably with sortase. The major pilin from strain SM101 was considered to be in an equilibrium state between an elongated and a bent structure through dynamic conformational change, which may be involved in pili-mediated colonization and sortase-mediated polymerization of pili.

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“…CppA-SM101 adopts a bent structure, and another type of bent structure was only found in GGSpaD (Chaurasia et al, 2018), as discussed later [ Supplementary Fig. S6(e)].…”

Section: Discussionmentioning

confidence: 80%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Structures of major pilins inClostridium perfringensdemonstrate dynamic conformational change

Tamai

Katayama

Sekiya

et al. 2019

Acta Cryst Sect D Struct Biol

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Lactobacillus rhamnosus GG triggers intestinal epithelium injury in zebrafish revealing host dependent beneficial effects

Zhang,

Yang

et al. 2024

iMeta

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Lactobacillus rhamnosus GG (LGG), the well‐characterized human‐derived probiotic strain, possesses excellent properties in the maintenance of intestinal homeostasis, immunoregulation and defense against gastrointestinal pathogens in mammals. Here, we demonstrate that the SpaC pilin of LGG causes intestinal epithelium injury by inducing cell pyroptosis and gut microbial dysbiosis in zebrafish. Dietary SpaC activates Caspase‐3−GSDMEa pathways in the intestinal epithelium, promotes intestinal pyroptosis and increases lipopolysaccharide (LPS)‐producing gut microbes in zebrafish. The increased LPS subsequently activates Gaspy2−GSDMEb pyroptosis pathway. Further analysis reveals the Caspase‐3−GSDMEa pyroptosis is initiated by the species‐specific recognition of SpaC by TLR4ba, which accounts for the species‐specificity of the SpaC‐inducing intestinal pyroptosis in zebrafish. The observed pyroptosis‐driven gut injury and microbial dysbiosis by LGG in zebrafish suggest that host‐specific beneficial/harmful mechanisms are critical safety issues when applying probiotics derived from other host species and need more attention.

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Crystal structure of the atypically adhesive SpaB basal pilus subunit: Mechanistic insights about its incorporation in lactobacillar SpaCBA pili

Megta

Pratap

Kant

et al. 2020

Current Research in Structural Biology

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To successfully colonize a host or environment, certain genera and species of Gram-positive bacteria have evolved to utilize the so-called sortase-dependent pilus, a long multi-subunit and non-flagellar surface adhesin. One example of this is Lactobacillus rhamnosus GG, a gut-adapted probiotic strain that produces SpaCBA pili. These structures are covalent hetero-oligomers built from three types of pilin subunit, each with a specific location and function (i.e., backbone SpaA for length, tip SpaC for adhesion, and basal SpaB for anchoring). Functionally, the SpaCBA pilus exhibits a promiscuous affinity for components on intestinal surfaces (e.g., mucus, collagen, and epithelial cells), which is largely attributed to the SpaC subunit. Then again, the basal SpaB pilin, in addition to acting as the terminal subunit during pilus assembly, displays an out of character mucoadhesive function. To address the structural basis of this unusual dual functionality, we reveal the 2.39 Å resolution crystal structure of SpaB. SpaB consists of one immunoglobulin-like CnaB domain and contains a putative intermolecular isopeptide bond-linking lysine and internal isopeptide bond-asparagine in an FP KN pilin motif within the C-terminal end. Remarkably, we found that a C-terminal stretch of positively charged lysine and arginine residues likely accounts for the atypical mucoadhesiveness of SpaB. Although harboring an autocatalytic triad of residues for a potential internal isopeptide interaction, the SpaB crystal structure lacked the visible electron density for intact bond formation, yet its presence was subsequently confirmed by mass spectral analysis. Finally, we propose a structural model that captures the exclusive basal positioning of SpaB in the SpaCBA pilus.

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Bent conformation of a backbone pilin N-terminal domain supports a three-stage pilus assembly mechanism

Cited by 12 publications

References 65 publications

Structures of major pilins inClostridium perfringensdemonstrate dynamic conformational change

Structures of major pilins inClostridium perfringensdemonstrate dynamic conformational change

Lactobacillus rhamnosus GG triggers intestinal epithelium injury in zebrafish revealing host dependent beneficial effects

Crystal structure of the atypically adhesive SpaB basal pilus subunit: Mechanistic insights about its incorporation in lactobacillar SpaCBA pili

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