Rational design of a global inhibitor of the virulence response in Staphylococcus aureus, based in part on localization of the site of inhibition to the receptor-histidine kinase, AgrC

The urgent need to develop a detection system for Staphylococcus aureus, one of the most common causes of infection, is prompting research towards novel approaches and devices, with a particular focus on point-of-care analysis. Biosensors are promising systems to achieve this aim. We coupled the selectivity and affinity of aptamers, short nucleic acids sequences able to recognize specific epitopes on bacterial surface, immobilized at high density on a nanostructured zirconium dioxide surface, with the rational design of specifically interacting fluorescent peptides to assemble an easy-to-use detection device. We show that the displacement of fluorescent peptides upon the competitive binding of S. aureus to immobilized aptamers can be detected and quantified through fluorescence loss. This approach could be also applied to the detection of other bacterial species once aptamers interacting with specific antigens will be identified, allowing the development of a platform for easy detection of a pathogen without requiring access to a healthcare environment.

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SpdC, a novel virulence factor, controls histidine kinase activity in Staphylococcus aureus

PLoS Pathogens ◽

10.1371/journal.ppat.1006917 ◽

2018 ◽

Vol 14 (3) ◽

pp. e1006917 ◽

Cited By ~ 17

Author(s):

Olivier Poupel ◽

Caroline Proux ◽

Bernd Jagla ◽

Tarek Msadek ◽

Sarah Dubrac

Keyword(s):

Staphylococcus Aureus ◽

Virulence Factor ◽

Histidine Kinase ◽

Kinase Activity

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A Point Mutation in the Sensor Histidine Kinase SaeS of Staphylococcus aureus Strain Newman Alters the Response to Biocide Exposure

Journal of Bacteriology ◽

10.1128/jb.00630-09 ◽

2009 ◽

Vol 191 (23) ◽

pp. 7306-7314 ◽

Cited By ~ 33

Author(s):

Daniel Schäfer ◽

Thiên-Trí Lâm ◽

Tobias Geiger ◽

Markus Mainiero ◽

Susanne Engelmann ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Point Mutation ◽

Histidine Kinase ◽

Promoter Activity ◽

Polyacrylamide Gel Electrophoresis ◽

Sodium Dodecyl ◽

Aureus Strain ◽

Sensor Histidine Kinase ◽

Qrt Pcr ◽

Cellular Invasiveness

ABSTRACT Staphylococcus aureus reacts to changing environmental conditions such as heat, pH, and chemicals through global regulators such as the sae (S. aureus exoprotein expression) two-component signaling system. Subinhibitory concentrations of some antibiotics were shown to increase virulence factor expression. Here, we investigated the S. aureus stress response to sublethal concentrations of a commonly used biocide (Perform), by real-time quantitative PCR (qRT-PCR), promoter activity assay, sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, and a flow cytometric invasion assay. Perform, acting through the production of reactive oxygen species, generally downregulated expression of extracellular proteins in strains 6850, COL, ISP479C but upregulated these proteins in strain Newman. Upregulated proteins were sae dependent. The Perform component SDS, but not paraquat (another oxygen donor), mimicked the biocide effect. Eap (extracellular adherence protein) was most prominently augmented. Upregulation of eap and sae was confirmed by qRT-PCR. Promoter activity of sae P1 was increased by Perform and SDS. Both substances enhanced cellular invasiveness, by 2.5-fold and 3.2-fold, respectively. Increased invasiveness was dependent on Eap and the sae system, whereas agr, sarA, sigB, and fibronectin-binding proteins had no major effect in strain Newman. This unique response pattern was due to a point mutation in SaeS (the sensor histidine kinase), as demonstrated by allele swapping. Newman saePQRS ISP479C behaved like ISP479C, whereas saePQRS Newman rendered ISP479C equally responsive as Newman. Taken together, the findings indicate that a point mutation in SaeS of strain Newman was responsible for increased expression of Eap upon exposure to sublethal Perform and SDS concentrations, leading to increased Eap-dependent cellular invasiveness. This may be important for understanding the regulation of virulence in S. aureus.

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Functional Reconstitution of Staphylococcus aureus Truncated AgrC Histidine Kinase in a Model Membrane System

PLoS ONE ◽

10.1371/journal.pone.0080400 ◽

2013 ◽

Vol 8 (11) ◽

pp. e80400 ◽

Cited By ~ 4

Author(s):

Lina Wang ◽

Chunshan Quan ◽

Baoquan Liu ◽

Jianfeng Wang ◽

Wen Xiong ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Histidine Kinase ◽

Membrane System ◽

Model Membrane

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Coagulase and Efb ofStaphylococcus aureusHave a Common Fibrinogen Binding Motif

mBio ◽

10.1128/mbio.01885-15 ◽

2016 ◽

Vol 7 (1) ◽

Cited By ~ 11

Author(s):

Ya-Ping Ko ◽

Mingsong Kang ◽

Vannakambadi K. Ganesh ◽

Dharmanand Ravirajan ◽

Bin Li ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Rational Design ◽

Tandem Repeats ◽

Repeat Unit ◽

Enzyme Linked Immunosorbent Assay ◽

Binding Motif ◽

Bacterial Cells ◽

Major Health Problem ◽

Bacterial Surface ◽

Fibrinogen Binding

ABSTRACTCoagulase (Coa) and Efb, secretedStaphylococcus aureusproteins, are important virulence factors in staphylococcal infections. Coa interacts with fibrinogen (Fg) and induces the formation of fibrin(ogen) clots through activation of prothrombin. Efb attracts Fg to the bacterial surface and forms a shield to protect the bacteria from phagocytic clearance. This communication describes the use of an array of synthetic peptides to identify variants of a linear Fg binding motif present in Coa and Efb which are responsible for the Fg binding activities of these proteins. This motif represents the first Fg binding motif identified for any microbial protein. We initially located the Fg binding sites to Coa’s C-terminal disordered segment containing tandem repeats by using recombinant fragments of Coa in enzyme-linked immunosorbent assay-type binding experiments. Sequence analyses revealed that this Coa region contained shorter segments with sequences similar to the Fg binding segments in Efb. An alanine scanning approach allowed us to identify the residues in Coa and Efb that are critical for Fg binding and to define the Fg binding motifs in the two proteins. In these motifs, the residues required for Fg binding are largely conserved, and they therefore constitute variants of a common Fg binding motif which binds to Fg with high affinity. Defining a specific motif also allowed us to identify a functional Fg binding register for the Coa repeats that is different from the repeat unit previously proposed.IMPORTANCEStaphylococcus aureusinfections are a major health problem that affects an estimated 50 million people globally and causes the death of about 20,000 Americans each year. A number of experimental vaccines have been developed during the past years. However, these vaccines have all failed in clinical trials. The ability ofS. aureusto form an Fg shield surrounding and protecting bacterial cells from clearance may explain why the vaccines are failing. Furthermore,S. aureuscoagulase can induce the formation of a fibrin(ogen) shield in experimental abscess models which surrounds and protects bacteria in the microcolony from clearance. In this study, we identified for the first time a microbial Fg binding motif. Variants of this motif are present in coagulase and Efb. Our results provide a molecular basis for the rational design of inhibitors that could potentially prevent the formation of the obstructing Fg shield.

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