Mimicry of the LL-37 N-terminus enhances the activity of short human cathelicidin derivatives

Issues such as potency and stability limit our ability to realize the potential of host defense peptides (HDPs) to serve as new antibiotics. In this work, we report the development of lead peptidomimetics based on human cathelicidin. Informed by our prior structure-activity work in full-length LL-37, we describe an enhanced minimal unit of activity in which the transposition of an N-terminal biphenyl motif from full-length LL-37 improves the activity of the previously-described central activity region (residues 18-29, KR-12) against gram-negative bacteria by >16-fold. Activity of this lead derivative, termed FF-14, is further improved through stabilizing modifications such as the application of D-amino acids and C-terminal amidation as well as selected N-lipidation moieties. FF-14 may therefore serve as a short, tractable, and intrinsically more potent primary sequence template on which to rationally apply additional modifications aimed at addressing remaining barriers to therapeutic application.