Studying Antimicrobial Peptide Mechanisms: Analysis of Novel HDAPS and Development of High-Throughput Techniques

Previously novel histone-derived antimicrobial peptides (HDAPs) were designed based on properties of Buforin 2, a peptide whose activity depends on membrane translocation, and DesHDAP1 and DesHDAP3 showed significant antibacterial activity. Their DNA binding, permeabilization, and translocation abilities were assessed independently and compared to antibacterial activity to determine whether the HDAPs share a mechanism with BF2. DesHDAP1 translocates effectively across lipid vesicle membranes while DesHDAP3 translocates poorly, and none of the DesHDAPs show significant membrane perturbation. Further investigation into the role of the proline hinge suggested that a proline hinge can promote membrane translocation in some peptides, but that the extent of its effect on permeabilization depends on the peptide’s amphipathic properties. In order to extend the scope of antimicrobial peptide screening in the Elmore lab, antimicrobial activity, permeabilization, and translocation screens compatible with high-throughput plate-reader software were also developed. While the initial antimicrobial activity and permeabilization screens attempted were not appropriate for this system, translocation screening was easily adapted to the plate-reader platform. Ultimately information about novel HDAPs provides insight into the potential mechanisms of such peptides, while development of high-throughput techniques extends the capacity to explore and analyze novel peptide libraries.