Structural Determinants of Antimicrobial and Antiplasmodial Activity and Selectivity in Histidine-rich Amphipathic Cationic Peptides

Alyae Boukhari,Gilles Moulay,Bernard Guerold,Antoine Kichler,A. James Mason,Marie-Háléne Metz-Boutigue,Philippe Bertani,Nelly Boehm,Arnaud Marquette,Ruairidh J.H. Sawers,Tamer Abdelrahman,Gilles Právost,Burkhard Bechinger,Wardi Moussaoui,Peiman Shooshtarizaheh,Ermanno Candolfi

doi:10.1074/jbc.m806201200

Alyae Boukhari, Gilles Moulay + Show 14 more

Open Access

https://doi.org/10.1074/jbc.m806201200

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Abstract

Designed histidine-rich amphipathic cationic peptides, such as LAH4, have enhanced membrane disruption and antibiotic properties when the peptide adopts an alignment parallel to the membrane surface. Although this was previously achieved by lowering the pH, here we have designed a new generation of histidine-rich peptides that adopt a surface alignment at neutral pH. In vitro, this new generation of peptides are powerful antibiotics in terms of the concentrations required for antibiotic activity; the spectrum of target bacteria, fungi, and parasites; and the speed with which they kill. Further modifications to the peptides, including the addition of more hydrophobic residues at the N terminus, the inclusion of a helix-breaking proline residue or using D-amino acids as building blocks, modulated the biophysical properties of the peptides and led to substantial changes in toxicity to human and parasite cells but had only a minimal effect on the antibacterial and antifungal activity. Using a range of biophysical methods, in particular solid-state NMR, we show that the peptides are highly efficient at disrupting the anionic lipid component of model membranes. However, we also show that effective pore formation in such model membranes may be related to, but is not essential for, high antimicrobial activity by cationic amphipathic helical peptides. The information in this study comprises a new layer of detail in the understanding of the action of cationic helical antimicrobial peptides and shows that rational design is capable of producing potentially therapeutic membrane active peptides with properties tailored to their function.

Highlights

Antimicrobial and Antiplasmodial Activity and Selectivity allel to the membrane surface [8], in common with a range of other cationic helical antibiotic peptides [11,12,13]
We used 2H NMR of chain deuterated lipids in mixed model membranes to show that cationic pleurocidin strongly destabilizes anionic lipid acyl chains, in preference to zwitterionic lipids, indicating that such peptides are capable of causing local membrane disruption [8] and pore formation [14] while the membrane remains otherwise intact
Peptide Design—Since LAH4 and its derivatives have much improved antibiotic activity at acidic pH when the peptide adopts an in-plane orientation with respect to the membrane [15], we designed peptides that retained the essential elements of the LAH4 peptides, namely the ␣-helicity and positioning of the histidine residues, while incorporating structural features that would provoke an in-plane orientation at neutral pH (Table 1)

Summary

Introduction

Antimicrobial and Antiplasmodial Activity and Selectivity allel to the membrane surface [8], in common with a range of other cationic helical antibiotic peptides [11,12,13].

Results

Conclusion