Here we report the design of membrane-active peptidomimetic molecules with a tunable arrangement of hydrophobic and polar groups. In spite of having the same chemical composition, the effective hydrophobicities of the compounds were different as a consequence of their chemical structure and conformational properties. The compound with lower effective hydrophobicity demonstrated antibacterial activity that was highly selective towards bacteria over mammalian cells. This study, highlighting the role in membrane selectivity of the specific arrangement of the different moieties in the molecular structure, provides useful indications for developing non-toxic antibacterial agents.

We developed a new class of inhibitors of protein–protein interactions of the SHP2 phosphatase, which is pivotal in cell signaling and represents a central target in the therapy of cancer and rare diseases. Currently available SHP2 inhibitors target the catalytic site or an allosteric pocket but lack specificity or are ineffective for disease-associated SHP2 mutants. Considering that pathogenic lesions cause signaling hyperactivation due to increased levels of SHP2 association with cognate proteins, we developed peptide-based molecules with nanomolar affinity for the N-terminal Src homology domain of SHP2, good selectivity, stability to degradation, and an affinity for pathogenic variants of SHP2 that is 2–20 times higher than for the wild-type protein. The best peptide reverted the effects of a pathogenic variant (D61G) in zebrafish embryos. Our results provide a novel route for SHP2-targeted therapies and a tool for investigating the role of protein–protein interactions in the function of SHP2.

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Mutations of PTPN11, the gene coding for the Src homology 2 domain-containing phosphatase 2 (SHP2), cause childhood leukemias and developmental disorders. SHP2 inhibitors targeting the catalytic site or an allosteric pocket lack specificity or are ineffective on pathogenic variants. In addition, several data indicate that increased association with cognate proteins, through its SH2 domains, rather than enhanced catalytic activity, is the main effect of mutations causing hyperactivation of SHP2-mediated signaling. We developed peptide-based molecules with low nM affinity to the N-SH2 domain and high specificity. These molecules bind to pathogenic variants of SHP2 with an affinity up to 20 times higher than to the wild-type protein, in contrast to allosteric inhibitors, and were able to revert the effects of a pathogenic SHP2 mutation in zebrafish embryos. Our results provide a novel route for SHP2-targeted therapies and a tool to investigate the role of protein-protein interactions in the function of SHP2.TABLE OF CONTENTS GRAPHICS