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Identification of Inhibitors of Pseudomonas aeruginosa Exotoxin-S ADP-Ribosyltransferase Activity

Pinto, Ana Filipa ; Ebrahimi, Mahsa ; Saleeb, Michael ; Forsberg, Åke ; Elofsson, Mikael and Schüler, Herwig LU orcid (2016) In Journal of Biomolecular Screening 21(6). p.5-590
Abstract

The gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen associated with drug resistance complications and, as such, an important object for drug discovery efforts. One attractive target for development of therapeutics is the ADP-ribosyltransferase Exotoxin-S (ExoS), an early effector of the type III secretion system that is delivered into host cells to affect their transcription pattern and cytoskeletal dynamics. The purpose of this study was to formulate a real-time assay of purified recombinant ExoS activity for high-throughput application. We characterized the turnover kinetics of the fluorescent dinucleotide 1,N(6)-etheno-NAD+ as co-substrate for ExoS. Further, we found that the toxin relied on any of five... (More)

The gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen associated with drug resistance complications and, as such, an important object for drug discovery efforts. One attractive target for development of therapeutics is the ADP-ribosyltransferase Exotoxin-S (ExoS), an early effector of the type III secretion system that is delivered into host cells to affect their transcription pattern and cytoskeletal dynamics. The purpose of this study was to formulate a real-time assay of purified recombinant ExoS activity for high-throughput application. We characterized the turnover kinetics of the fluorescent dinucleotide 1,N(6)-etheno-NAD+ as co-substrate for ExoS. Further, we found that the toxin relied on any of five tested isoforms of human 14-3-3 to modify vH-Ras and the Rho-family GTPases Rac1, -2, and -3 and RhoC. We then used 14-3-3β-stimulated ExoS modification of vH-Ras to screen a collection of low-molecular-weight compounds selected to target the poly-ADP ribose polymerase family and identified 3-(4-oxo-3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-2-yl)propanoic acid as an ExoS inhibitor with micromolar potency. Thus, we present an optimized method to screen for inhibitors of ExoS activity that is amenable to high-throughput format and an intermediate affinity inhibitor that can serve both as assay control and as a starting point for further development.

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author
; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
keywords
14-3-3 Proteins/chemistry, ADP Ribose Transferases/antagonists & inhibitors, Bacterial Toxins/antagonists & inhibitors, Drug Discovery, Drug Resistance, Bacterial, Exotoxins/antagonists & inhibitors, Host-Pathogen Interactions/genetics, Humans, Pseudomonas Infections/drug therapy, Pseudomonas aeruginosa/drug effects, Small Molecule Libraries/pharmacology, Substrate Specificity, rac1 GTP-Binding Protein/chemistry
in
Journal of Biomolecular Screening
volume
21
issue
6
pages
6 pages
publisher
SAGE Publications
external identifiers
  • pmid:26850638
  • scopus:84975893924
ISSN
1087-0571
DOI
10.1177/1087057116629923
language
English
LU publication?
no
additional info
© 2016 Society for Laboratory Automation and Screening.
id
afc83d95-6818-419d-9512-cce1f8e7ec45
date added to LUP
2024-11-21 17:52:53
date last changed
2025-01-03 07:43:01
@article{afc83d95-6818-419d-9512-cce1f8e7ec45,
  abstract     = {{<p>The gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen associated with drug resistance complications and, as such, an important object for drug discovery efforts. One attractive target for development of therapeutics is the ADP-ribosyltransferase Exotoxin-S (ExoS), an early effector of the type III secretion system that is delivered into host cells to affect their transcription pattern and cytoskeletal dynamics. The purpose of this study was to formulate a real-time assay of purified recombinant ExoS activity for high-throughput application. We characterized the turnover kinetics of the fluorescent dinucleotide 1,N(6)-etheno-NAD+ as co-substrate for ExoS. Further, we found that the toxin relied on any of five tested isoforms of human 14-3-3 to modify vH-Ras and the Rho-family GTPases Rac1, -2, and -3 and RhoC. We then used 14-3-3β-stimulated ExoS modification of vH-Ras to screen a collection of low-molecular-weight compounds selected to target the poly-ADP ribose polymerase family and identified 3-(4-oxo-3,5,6,7-tetrahydro-4H-cyclopenta[4,5]thieno[2,3-d]pyrimidin-2-yl)propanoic acid as an ExoS inhibitor with micromolar potency. Thus, we present an optimized method to screen for inhibitors of ExoS activity that is amenable to high-throughput format and an intermediate affinity inhibitor that can serve both as assay control and as a starting point for further development.</p>}},
  author       = {{Pinto, Ana Filipa and Ebrahimi, Mahsa and Saleeb, Michael and Forsberg, Åke and Elofsson, Mikael and Schüler, Herwig}},
  issn         = {{1087-0571}},
  keywords     = {{14-3-3 Proteins/chemistry; ADP Ribose Transferases/antagonists & inhibitors; Bacterial Toxins/antagonists & inhibitors; Drug Discovery; Drug Resistance, Bacterial; Exotoxins/antagonists & inhibitors; Host-Pathogen Interactions/genetics; Humans; Pseudomonas Infections/drug therapy; Pseudomonas aeruginosa/drug effects; Small Molecule Libraries/pharmacology; Substrate Specificity; rac1 GTP-Binding Protein/chemistry}},
  language     = {{eng}},
  number       = {{6}},
  pages        = {{5--590}},
  publisher    = {{SAGE Publications}},
  series       = {{Journal of Biomolecular Screening}},
  title        = {{Identification of Inhibitors of <i>Pseudomonas aeruginosa</i> Exotoxin-S ADP-Ribosyltransferase Activity}},
  url          = {{http://dx.doi.org/10.1177/1087057116629923}},
  doi          = {{10.1177/1087057116629923}},
  volume       = {{21}},
  year         = {{2016}},
}