Most living organisms have defense mechanisms to deal with external threats. Venoms from different species have been increasingly researched for their potential as antimicrobials, specifically focusing on antimicrobial peptides (AMPs). The Ponericin L1 peptide, derived from the ponerine ant Neoponera goeldii, exhibits broad spectrum antimicrobial activity. Notably, many AMPs consist of hydrophobic side chains with an overall cationic net charge which form a facially amphiphilic helical conformation, however L1 does not adopt this facially amphiphilic structure. We carried out a sequence-structure-activity relationship study focusing on the overall peptide charge, side chain identity, and hydrophobic content. The role of cationic residues was also investigated by replacing the naturally occurring Lys with Arg, ornithine, and diaminopropionic acid. Hydrophobic effects were investigated by changing all hydrophobic residues to either Leu, Val, Ile, or Ala. Utilizing the naturally occurring Trp within the peptide chain, we implemented fluorescence spectroscopy to assess binding modeling lipid membranes at various compositions. Circular dichroism studies show that the peptide does adopt an alpha-helical conformation. Membrane permeabilization assays of bacteria and red blood cells show that this family of peptides likely act through a membrane disruption mechanism. Antimicrobial assays mirror the leakage assays with low activity for those peptides that did not permeabilize bacterial membranes.

Sequence-structure-activity relationship in the venom peptide ponericin L1

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.