A Novel Strategy for the Design of Aurein 1.2 Analogs with Enhanced Bioactivities by Conjunction of Cell-Penetrating Regions

Abstract

The rational design modification of membrane-active peptide structures by introducing additional membrane-penetrating regions has become a good strategy for the improvement of action and potency. Aurein 1.2 (GLFDIIKKIAESF-NH2) is a multifunctional antimicrobial peptide isolated from the green and golden bell frog, Litoria aurea, and the southern bell frog Litoria raniformis skin secretions. Its bio-functionality has been widely investigated. However, its lack of a potent action failed to provide aurein 1.2 with a competitive edge for further development as a therapeutic agent for clinical use. Herein, aurein 1.2 was chosen as a template for rational modification to achieve a more potent bio-functionality. KLA-2 (GLFDIIKKLAKLAESF-NH2), which a double KLA region inserted into the sequence, presented a 2–16-fold enhancement of antimicrobial activity, a 2–8-fold greater anti-biofilm activity (including biofilm prevention and eradication), and a 7-fold more potent anti-proliferation activity and hence was regarded as the most broad-spectrum active peptide. Additionally, with respect to antimicrobial activity, the IIKK-modified analog, IK-3 (GLFDIIKKIIKKIIKKI-NH2), also demonstrated a potent enhancement of activity against various pathogens, exhibiting a 2–8-fold enhanced activity compared to the parent peptide. Moreover, the selectivities of KLA-1 and KLA-2 were enhanced significantly. In conclusion, peptide modification, through the introduction of additional membrane penetrating regions, can increase both the potency and activity spectra of natural template peptides, making them suitable candidates for new drug development.

Free Energy Analysis of Peptide-Induced Pore Formation in Lipid Membranes by Bridging Atomistic and Coarse-Grained Simulations

“…16 In the pore formation mechanism, AMPs stabilize membrane-spanning pores that compromise the membrane's ability to regulate transport. Melittin, a 26-residue +6 charged peptide that is the major component of bee venom, 17,18 is an example of an AMP believed to disrupt membranes via pore formation as supported by x-ray diffraction 19 and calcein leakage experiments. 20 Pore formation can be further subdivided into two separate mechanisms: the barrel-stave mechanism, in which peptides completely line the walls of the pore to minimize lipid disruption, and the toroidal pore mechanism, in which a combination of peptides and lipid head groups line the pore.…”