title: Minimum amino acid residues of an α-helical peptide leading to lipid nanodisc formation.
abstract: Nanodiscs are a relatively new class of nanoparticles composed of amphiphilic α-helical scaffold peptides and a phospholipid bilayer, and find potential applications in various fields. In order to identify the minimum number of amino acid residues of an amphiphilic α-helical peptide that leads to nanodisc formation, seven peptides differing in lengths (22-, 18-, 14-, 12-, 10-, 8-, and 6-mers) that mimic and modify the C-terminal domain of apoA-I (residues 220-241) were synthesized. At a concentration of 0.3 mM, the 6- and 8-mer peptides did not present any surface activity. In case of the 10-mer peptide, the aqueous surface tension initially decreased and reached a constant value of 51.9 mN/m with the 14-, 18-, and 22-mer peptides. Moreover, upon mixing the surface-active peptides (14-, 18-, and 22-mers) with dipalmitoylphosphatidylcholine (DMPC) liposomes (2.5:1, peptide : DMPC), the turbid DMPC liposome solution rapidly became transparent. Further analysis of this solution by negative-stain transmission electron microscopy (NS-TEM) indicated the presence of disk-like nanostructures. The average diameter of the nanodiscs formed was 9.5 ± 2.7 nm for the 22-mer, 8.1 ± 2.7 nm for the 18-mer, and 25.5 ± 8.5 nm for the 14-mer peptides. These results clearly demonstrate that the surface properties of peptides play a critical role in nanodisc formation. Furthermore, the minimum length of an amphiphilic peptide from the C-terminal of apoA-I protein that can lead to nanodisc formation is 14 amino acid residues.
authors.affiliation: Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST).
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Imura
authors.forename: Yohei
authors.initials: Y
authors.lastname: Tsukui
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sakai
authors.forename: Hideki
authors.initials: H
authors.lastname: Sakai
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Taira
authors.forename: Dai
authors.initials: D
authors.lastname: Kitamoto
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D016632:Apolipoprotein A-I / Q000138:chemical synthesis / Q000737:chemistry* / Q000648:ultrastructure; D008051:Lipid Bilayers; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013500:Surface Tension; D014867:Water
chemical_list: D000596:Amino Acids; D016632:Apolipoprotein A-I; D008051:Lipid Bilayers; D008055:Lipids; D008081:Liposomes; D010455:Peptides; D014867:Water; D015060:1,2-Dipalmitoylphosphatidylcholine