Amphipathic Peptide–Phospholipid Nanofibers: Phospholipid Specificity and Dependence on Concentration and Temperature

Abstract

The design of nanoassemblies is an important part of the development of new materials for applications in nanomedicine and biosensors. In our previous study, cysteine substitution of the apolipoprotein A-I-derived peptide 18A at residue 11, 18A­[A11C], bound to 1-palmitoyl-2-oleoylphosphatidylcholine to form fibrous aggregates at a lipid-to-peptide molar ratio of ≤2 and a fiber diameter of 10–20 nm. However, the mechanisms underlying the lipid–peptide interactions that enable nanofiber formation remain unclear. Here, we evaluated the phospholipid specificity, concentration dependence, and temperature dependence of the formation of 18A­[A11C]–lipid nanofibers. Nanofibers were found to form in the presence of specific phospholipids and have a constant lipid/peptide stoichiometry of 1.2 ± 0.2. Moreover, an increase in the length of the acyl chain in phosphatidylcholines was found to increase the structural stability of the nanofibers. These results indicate that specific molecular interactions between peptides and both the headgroups and acyl chains of phospholipids are involved in nanofiber formation. Furthermore, the formation and disassembly of the nanofibers were reversibly controlled by changes in temperature and concentration. The results of the present study provide an insight into the creation of nanoassembling structures.

Solubilization of Phospholipid by Surfactin Leading to Lipid Nanodisc and Fibrous Architecture Formation

“…Akiba et al reported that cyclohexane solutions of SF form organogels by entanglement of supramolecular nanofibers [ 29 ]. Ikeda et al reported a phospholipid-specific formation of lipid–peptide nanofibers [ 30 ]. These results suggest that the fibrous structures, as shown in Figure 6 , of the DMPC/SF mixture consist of a single structural unit assembly.…”

Improvement of Thermal Stability of Amphipathic Peptide–Phospholipid Nanodiscs via Lateral Association of α-Helices by Disulfide Cross-Linking

“…Then, the solution was incubated for 1–7 days at 25 °C to evaluate the effects of the spontaneous formation of disulfide bonds in the complex. EDTA was added as a control to inhibit the disulfide bond formation by the chelate formation of residual metal cations in the solution. , We also prepared a solution containing an oxidizing agent K 3 Fe­(CN) 6 to promote disulfide bond formation. In all the conditions of peptide–lipid mixtures prepared, the formation of nanoparticles with a size of approximately 10–20 nm was confirmed by DLS measurements at 25 °C (Figure ).…”