title: Chemical probes for competitive profiling of the quorum sensing signal synthase PqsD ofPseudomonas aeruginosa.
abstract: The human pathogenPseudomonas aeruginosauses thepqsquorum sensing system to coordinate the production of its broad spectrum of virulence factors to facilitate colonization and infection of its host. Hereby, the enzyme PqsD is a virulence related quorum sensing signal synthase that catalyzes the central step in the biosynthesis of thePseudomonasquinolone signals HHQ and PQS. We developed a library of cysteine reactive chemical probes with an alkyne handle for fluorescence tagging and report the selective and highly sensitive in vitro labelling of the active site cysteine of this important enzyme. Interestingly, only one type of probe, with a reactive α-chloroacetamide was capable of covalently reacting with the active site. We demonstrated the potential of our probes in a competitive labelling platform where we screened a library of synthetic HHQ and PQS analogues with heteroatom replacements and found several inhibitors of probe binding that may represent promising scaffolds for the development of customized PqsD inhibitors as well as a chemical toolbox to investigate the activity and active site specificity of the enzyme.
authors.affiliation: Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Prothiwa
authors.affiliation: Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Dávid
authors.initials: D
authors.lastname: Szamosvári
authors.affiliation: Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Glasmacher
authors.affiliation: Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Böttcher
keywords: PqsD; Pseudomonas aeruginosa; activity-based probes; protein labelling; quinolones