title: Lipid-dependent pore formation by antimicrobial peptides arenicin-2 and melittin demonstrated by their proton transfer activity.
abstract: This work presents a comparative study of proton transfer activity (PTA) of two cationic (+6) antimicrobial peptides, β-structural arenicin-2 and α-helical melittin. A new approach was proposed for the detection of passive proton transfer by using proteoliposomes containing bacteriorhodopsin, which creates a small light-induced electrochemical proton gradient ∆ΔpH. Addition of several nanomoles of the peptides lowers ∆ΔpH that is proximately indicative of the pore formation. The quantitative analysis of sigmoidal dependences of ∆pH on the peptides concentration was carried out using liposomes prepared from PC, PC/PE, PC/PE/PI and PC/PG. Substitution of PC-containing liposomes with PE-containing ones, having negative spontaneous curvature, reduced the PTA of α-helical melittin and increased that of β-structural arenicin-2. This result indicates an essential difference in the pore formation by these peptides. Further increase of PTA in response to arenicin-2 (in contrast to melittin) was observed in the liposomes prepared from PC/PE/PI. The data analysis leads to the conclusion that PTA is influenced by (i) efficiency of the pore assemblage, which depends on the structure of pore-forming peptides, and the spontaneous curvature of lipids and (ii) the presence of mobile protons in the polar head groups of phospholipids.
authors.affiliation: Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya St, 16/10, 117997, Moscow, Russia.
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Sychev
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Balandin
authors.forename: Pavel V
authors.initials: PV
authors.lastname: Panteleev
authors.forename: Leonid I
authors.initials: LI
authors.lastname: Barsukov
authors.forename: Tatiana V
authors.initials: TV
authors.lastname: Ovchinnikova
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism*; D001436:Bacteriorhodopsins / Q000737:chemistry / Q000378:metabolism*; D015801:Helminth Proteins / Q000737:chemistry / Q000378:metabolism*; D008555:Melitten / Q000737:chemistry / Q000378:metabolism*; D011510:Proteolipids / Q000737:chemistry / Q000378:metabolism*; D011522:Protons
chemical_list: D023181:Antimicrobial Cationic Peptides; D015801:Helminth Proteins; D011510:Proteolipids; D011522:Protons; C496888:arenicin-1, Arenicola marina; C020485:proteoliposomes; D008555:Melitten; D001436:Bacteriorhodopsins
keywords: antimicrobial peptide; arenicin; melittin; proton transfer; spontaneous curvature; toroidal pore; β-hairpin