Reymond Research Group

University of Bern


An intrinsically disordered antimicrobial peptide dendrimer from stereorandomized virtual screening

Our paper An intrinsically disordered antimicrobial peptide dendrimer from stereorandomized virtual screening is published in
Cell Reports Physical Science!

Highlights:
• Stereorandomized antimicrobial peptide dendrimers are identified by virtual screening

• A switch to L residues induces α-helical folding and strong toxicity in one sr-AMPD

• Another AMPD remains intrinsically disordered, active, and non-toxic as L-AMPD

Summary:
Membrane-disruptive amphiphilic antimicrobial peptides behave as intrinsically disordered proteins by being unordered in water and becoming α-helical in contact with biological membranes. We recently discovered that synthesizing the α-helical antimicrobial peptide dendrimer L-T25 ((KL)8(KKL)4(KLL)2KKLL) using racemic amino acids to form stereorandomized sr-T25, an analytically pure mixture of all possible diastereoisomers of L-T25, preserved antibacterial activity but abolished hemolysis and cytotoxicity, pointing to an intrinsically disordered antibacterial conformation and an α-helical cytotoxic conformation. In this study, to identify non-toxic intrinsically disordered homochiral antimicrobial peptide dendrimers (AMPDs), we surveyed sixty-three sr-analogs of sr-T25 selected by virtual screening. One of the analogs, sr-X18 ((KL)8(KLK)4(KLL)2KLLL), lost antibacterial activity as L-enantiomer and became hemolytic due to α-helical folding. By contrast, the L- and D-enantiomers of sr-X22 ((KL)8(KL)4(KKLL)2KLKK) were equally antibacterial, non-hemolytic, and non-toxic, implying an intrinsically disordered bioactive conformation. Screening stereorandomized libraries may be generally useful to identify or optimize intrinsically disordered bioactive peptides.

Author(s):
Xingguang Cai, Markus Orsi, Alice Capecchi, Thilo Köhler, Christian van Delden, Sacha Javor, and Jean-Louis Reymond