Surfactant-like Properties of an Amphiphilic 伪-Helical Peptide Leading to Lipid Nanodisc Formation

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• 作者：Tomohiro Imura ; Yohei Tsukui ; Toshiaki Taira ; Kenichi Aburai ; Kenichi Sakai ; Hideki Sakai ; Masahiko Abe ; Dai Kitamoto
• 刊名：Langmuir
• 出版年：2014
• 出版时间：April 29, 2014
• 年：2014
• 卷：30
• 期：16
• 页码：4752-4759
• 全文大小：318K
• 年卷期：v.30,no.16(April 29, 2014)
• ISSN：1520-5827

文摘

Nanodiscs are self-assembled discoidal nanoparticles composed of amphiphilic 伪-helical scaffold proteins or peptides that wrap themselves around the circumference of a lipid bilayer in a beltlike manner. In this study, an amphiphilic helical peptide that mimics helix 10 of human apoA-I was newly synthesized by solid phase peptide synthesis using Fmoc chemistry, and its physicochemical properties, including surface tension, self-association, and solubilization abilities, were evaluated and related directly to nanodisc formation. The synthesized peptide having hydrophobic and hydrophilic faces behaves like a general surfactant, affording a critical association concentration (CAC) of 2.7 脳 10^鈥? M and a 纬_CAC of 51.2 mN m^鈥? in aqueous solution. Interestingly, only a peptide solution above its CAC was able to microsolubilize L-伪-dimyristoylphosphatidylcholine (DMPC) vesicles, and lipid nanodiscs with an average diameter of 9.5 卤 2.7 nm were observed by dynamic light scattering and negative stain transmission electron microscopy. Moreover, the 味 potentials of the lipid nanodiscs were measured for the first time as a function of pH, and the values changed from positive (20 mV) to negative (鈭?0 mV). In particular, nanodisc solutions at acidic pH 4 (20 mV) or basic pH 9 (鈭?0 mV) were found to be stable for more than 6 months as a result of the electrostatic repulsion between the particles.