Stereoisomers of P. aeruginosa autoinducer analog to probe the regulator binding site.

Quorum sensing (QS) regulates the production of virulence factors and the maturation of biofilms in many bacteria, including Pseudomonas aeruginosa. The QS cascade is activated by the interaction of bacterial signaling molecules, called autoinducers (AIs), with their corresponding regulatory proteins. Here, we report a series of studies to define the stereochemical preferences of synthetic agonists and perform docking studies to understand the microenvironment of the binding site in P. aeruginosa QS regulators. One of the key findings of this work is that the ring structure and the absolute and relative stereochemistries of the amide and hydroxyl groups dictate the agonist activity. This study aids in determining important structural and stereochemical characteristics necessary for interaction with the QS regulatory proteins, thus expanding our understanding of their inducer binding sites.