N-Salicyl-AA(n)-picolamide Foldameric Peptides Exhibit Quorum Sensing Inhibition of Pseudomonas aeruginosa (PA14)

[Image: see text] An organic acid, salicylic acid, and its derivatives are constituents of various natural products possessing remarkable bioactivity. O-Acetyl salicylate (aspirin) is a well-known life-saving drug. Its peptide derivative salicylamide has also been explored in the designing of peptide-based therapeutic drugs. An organic base, picolylamine has been recently explored for designing diagnostic probes. However, both the acid and base have common features as metal chelating with coordinating metals. Thus, these scaffolds could be used for designing inhibitors of various metalloenzymes. Their characteristic properties encourage us to design peptides containing both scaffolds (salicylic acid and picolylamine) at opposite terminals. So far there is no report available on such conjugated peptides. This report describes the synthesis, conformational analysis, and biochemical assessment of rationally designed N-salicyl-AA(n)-picolamide peptides. Pleasantly, we have obtained the crystal structures of representative peptides that confirm their roles in conformational changes. Our biological assessment as quorum sensing inhibitors has revealed that their di/tripeptides inhibit quorum sensing of the pathogenic bacterium PA14 strain. Hence, these peptides have promising foldameric and therapeutic values.