A new structural class of bacterial thioester domains reveals a slipknot topology

Miller, Ona Kealoha; Banfield, Mark J.; Schwarz‐Linek, Ulrich

doi:10.1002/pro.3478

Cited by 16 publications

(30 citation statements)

References 27 publications

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“…These are surface-associated proteins in Gram-positive bacteria and are suggested to participate in covalent adhesion. Whereas the target of BaTIE binding remains unknown (24), RrgC is covalently attached to the outer PG layer of the streptococcal cell wall (25). We reasoned that RgsD was likely to have affinity to PG and therefore tested whether it interacts with PG.…”

Section: Resultsmentioning

confidence: 99%

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Krol

Yau

Lechner

et al. 2020

mBio

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Sinorhizobium meliloti is an alphaproteobacterium belonging to the Rhizobiales. Bacteria from this order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein interaction partners of the previously characterized polar growth factors RgsP and RgsM, we identified the inner membrane components of the Tol-Pal system (TolQ and TolR) and novel Rgs (rhizobial growth and septation) proteins with unknown functions. TolQ, Pal, and all Rgs proteins, except for RgsE, were indispensable for S. meliloti cell growth. Six of the Rgs proteins, TolQ, and Pal localized to the growing cell pole in the cell elongation phase and to the septum in predivisional cells, and three Rgs proteins localized to the growing cell pole only. The putative FtsN-like protein RgsS contains a conserved SPOR domain and is indispensable at the early stages of cell division. The components of the Tol-Pal system were required at the late stages of cell division. RgsE, a homolog of the Agrobacterium tumefaciens growth pole ring protein GPR, has an important role in maintaining the normal growth rate and rod cell shape. RgsD is a periplasmic protein with the ability to bind peptidoglycan. Analysis of the phylogenetic distribution of the Rgs proteins showed that they are conserved in Rhizobiales and mostly absent from other alphaproteobacterial orders, suggesting a conserved role of these proteins in polar growth. IMPORTANCE Bacterial cell proliferation involves cell growth and septum formation followed by cell division. For cell growth, bacteria have evolved different complex mechanisms. The most prevalent growth mode of rod-shaped bacteria is cell elongation by incorporating new peptidoglycans in a dispersed manner along the sidewall. A small share of rod-shaped bacteria, including the alphaproteobacterial Rhizobiales, grow unipolarly. Here, we identified and initially characterized a set of Rgs (rhizobial growth and septation) proteins, which are involved in cell division and unipolar growth of Sinorhizobium meliloti and highly conserved in Rhizobiales. Our data expand the knowledge of components of the polarly localized machinery driving cell wall growth and suggest a complex of Rgs proteins with components of the divisome, differing in composition between the polar cell elongation zone and the septum.

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Section: Resultsmentioning

confidence: 99%

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Krol

Yau

Lechner

et al. 2020

mBio

View full text Add to dashboard Cite

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“…These are surface-associated proteins in Gram-positives and suggested to participate in covalent adhesion. Whereas the target of BaTIE binding remained unknown (24), RrgC is covalently attached to the outer PG layer of the streptococcal cell wall (25). We reasoned that RgsD was likely to have affinity to PG and therefore tested whether it interacted with PG.…”

Section: Resultsmentioning

confidence: 99%

Tol-Pal system and Rgs proteins interact to promote unipolar growth and cell division inSinorhizobium meliloti

Krol

Yau

Lechner

et al. 2020

Preprint

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19Sinorhizobium meliloti is an -proteobacterium belonging to the Rhizobiales. Bacteria from this 20 order elongate their cell wall at the new cell pole, generated by cell division. Screening for protein 21 interaction partners of the previously characterized polar growth factors RgsP and RgsM, we 22 42 knowledge of components of the polarly localized machinery driving cell wall growth and suggest 43 a complex of Rgs proteins with components of the divisome, differing in composition between 44 the polar cell elongation zone and the septum.45

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“…Most of these adhesins interact with extracellular matrix proteins-such as fibrinogen and collagen 46,47 -and establish non-covalent bonds with their ligands. In addition to these, it was recently discovered the existence of thioester bond-adhesins in some Gram positive organisms [5][6][7] .…”

Section: Discussionmentioning

confidence: 99%

“…Intramolecular thioester bonds are uncommon in the structure of proteins, having been only identified in the immune complement proteins, in α2-macroglobulin anti-protease [49][50][51] , and in Gram positive adhesins 6,7 . In the case of non-activated complement proteins, nucleophilic cleavage and reformation can occur 52 , but the proteolytic activation of these proteins leads to a rapid and irreversible binding to its target substrates 53 , which contrasts with the reversible and forcemodulated reactivity of S. pyogenes adhesin.…”

Section: Discussionmentioning

confidence: 99%

“…In the ancient arms race between host and pathogen, bacteria have evolved novel adhesion strategies such as biofilm formation 1,2 , non-covalent catch bond binding 3,4 , and direct covalent binding to host substrates 5,6 . In particular, Gram positive bacteria express a class of protein adhesins that contain internal Cys-Gln thioester bonds [5][6][7] . The thioester bond functions as an electrophilic substrate to draw a nucleophilic ligand, creating a covalent crosslink between a ligand and the adhesin of the bacterium 6 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Protein folding modulates the adhesion strategy of Gram positive pathogens

Alonso-Caballero¹,

Echelman²,

Tapia‐Rojo³

et al. 2019

Preprint

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Gram positive bacteria colonize mucosal tissues against large mechanical perturbations, such as coughing, which generate large shear forces that exceed the ability of non-covalent bonds to remain attached. To overcome these challenges, the pathogen Streptococcus pyogenes utilizes the protein Cpa, a pilus tip-end adhesin equipped with a Cys-Gln thioester bond. The reactivity of this bond towards host surface ligands enables covalent anchoring of the bacterium, allowing it to resist large mechanical shocks; however, colonization also requires cell migration and spreading over surfaces. The molecular mechanisms underlying these seemingly incompatible requirements remain unknown. Here, we demonstrate a magnetic tweezers force spectroscopy assay that resolves the dynamics of Cpa thioester bond under force. While folded at forces < 6 pN, Cpa thioester bond reacts reversibly with amine ligands, of common occurrence in inflammation sites; however, mechanical unfolding and exposure to forces higher than 35 pN blocks thioester reactivity entirely. We propose that this folding-coupled thioester reactivity switch allows the adhesin to hop and sample host surface ligands at low force (nomadic mobility phase), and yet gets covalently anchored in place while under mechanical stress (locked phase). We dub such bonds "smart covalent bonds", adding a novel class to the known repertoire of non-covalent adhesion strategies that include slip bonds, and catch bonds.

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A new structural class of bacterial thioester domains reveals a slipknot topology

Cited by 16 publications

References 27 publications

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Tol-Pal System and Rgs Proteins Interact to Promote Unipolar Growth and Cell Division in Sinorhizobium meliloti

Tol-Pal system and Rgs proteins interact to promote unipolar growth and cell division inSinorhizobium meliloti

Protein folding modulates the adhesion strategy of Gram positive pathogens

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