Structure-function relationship of model Aib-containing peptides as ion transfer intermembrane templates
Structure-function relationship of model Aib-containing peptides as ion transfer intermembrane templates
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DOI：
10.1093/oxfordjournals.jbchem.a022340
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发表时间：
1999-04-01
影响因子：
2.7
通讯作者：
Kondo, M
中科院分区：
文献类型：
--
作者：
Higashimoto, Y;Kodama, H;Kondo, M
肽基化合物包括一个具有高含量的a-氨基异丁酸（Aib）残基和c端氨基醇的肽类抗生素家族。这些肽形成a-螺旋结构，导致脂质膜中的电压门控离子通道。在本研究中，我们设计了不同链长的两亲性螺旋状含aib肽Ac-(Aib-Lys-Aib-Ala)(n)- nh2 (n = 1-5)，以研究螺旋基序在脂质双分子层膜中的聚集和跨膜取向机制。采用常规的Fmoc逐步固相法合成多肽。所得粗肽收率高（66 ~ 85%），纯度高（69 ~ 95%），利用CD光谱对合成肽进行了构象分析。结果表明，这些肽具有高度螺旋结构，且螺旋度随链长增加而增加。最长的肽Ac-(Aib-Lys-Aib-Ala)(5)- nh2在脂质体中自聚集并呈桶状壁构象，Ac-(Aib-Lys-Aib-Ala)(5)- nh2对革兰氏阳性菌具有较强的抗菌活性。膜片钳测量显示，这种肽可以在相对较低的跨层电位和肽浓度下形成具有长寿命的明确的离子通道。对于该肽，最常见事件的单通道电导为227 pS，这可能与单态四聚体孔有关。
Peptaibols comprise a family of peptide antibiotics with high contents of a-aminoisobutyric acid (Aib) residues and C-terminal amino alcohols. These peptides form a-helical structures leading to voltage-gated ion channels in lipid membranes. In the present study, amphiphilic helical Aib-containing peptides of various chain-lengths, Ac-(Aib-Lys-Aib-Ala)(n)-NH2 (n = 1-5), were designed to investigate the mechanisms of the aggregation and transmembrane orientation of helical motifs in lipid bilayer membranes. Peptide synthesis was performed by the conventional stepwise Fmoc solid-phase method. The crude peptides were obtained in high yields (66-85%) with high purities (69-95%), Conformational analysis of the synthetic peptides was performed by CD spectroscopy. It was found that these peptides take on highly helical structures, and the helicity of the peptides increases with an increase in chain-length. The longest peptide, Ac-(Aib-Lys-Aib-Ala)(5)-NH2, self-aggregates and adopts a barrel-stave conformation in liposomes, Ac-(Aib-Lys-Aib-Ala)(5)-NH2 exhibited potent antimicrobial activity against Gram-positive bacteria. Patch-clamp measurements revealed that this peptide can form well-defined ion channels with a long lifetime at relatively low transbilayer potentials and peptide concentrations. For this peptide, the single-channel conductance of the most frequent event is 227 pS, which could be related to a single-state tetrameric pore.