The amphipathic helix concept:: length effects on ideally amphipathic LiKj(i=2j) peptides to acquire optimal hemolytic activity
The amphipathic helix concept:: length effects on ideally amphipathic LiKj(i=2j) peptides to acquire optimal hemolytic activity
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DOI：
10.1016/s0005-2736(98)00219-3
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发表时间：
1999-01-12
影响因子：
3.4
通讯作者：
Dufourcq, J
中科院分区：
文献类型：
--
作者：
Castano, S;Cornut, I;Dufourcq, J
在对裂解毒素建模的最低限度方法中，研究了具有i= 2 j组成且长度从5至22个残基变化的LiKj的两亲性肽诱导溶血和脂质囊泡渗漏的能力。它们的序列被设计为产生理想的两亲性α螺旋，每个推定的转角具有单个K残基。所有的肽都是裂解性的，它们的活性从最短的5个残基长的肽（5聚体）到最长的22聚体变化超过10（3）倍。然而，没有单调的增加与长度。15-mer与22-mer一样具有活性，甚至超过用作标准品的蜂毒肽。从缓冲液到膜的分配系数随长度增加至12个残基，然后微弱下降至达到平台期，而预计它们随肽长度和疏水性单调增加，如HPLC保留时间所示。荧光标记的丹磺酰基基团在N-末端，或由一个W附近的CO-末端，表明，多达12个残基，肽基本上是单体，而较长的肽强烈聚集在溶液中。然后通过肽长度控制脂质亲和力，并发现其受到缓冲液中折叠和自缔合的限制。裂解活性导致两个从脂质亲和力，这是由一个因素的20倍的变化，并从效率干扰膜结合时，后者急剧和单调增加的长度。15个残基长的肽KLLKLLLKLLLKLLK具有最高裂解活性的最佳大小。荧光标记在脂质中的浅位置进一步证明了肽在界面处保持平坦的模型。(C)1999 Elsevier Science B. V.保留所有权利。
In a minimalist approach to modeling lytic toxins, amphipathic peptides of LiKj with i=2j composition and whose length varies from 5 to 22 residues were studied for their ability to induce hemolysis and lipid vesicle leakage. Their sequences were designed to generate ideally amphipathic a helices with a single K residue per putative turn. All the peptides were lytic, their activities varying by more than a factor of 10(3) from the shortest 5-residue-long peptide (5-mer) to the longest 22-mer. However, there was no monotonous increase versus length. The 15-mer was as active as the 22-mer and even more than melittin which is used as standard. Partition coefficients from the buffer to the membrane increased in relation to length up to 12 residues, then weakly decreased to reach a plateau, while they were expected to increase monotonously with peptide length and hydrophobicity as revealed from HPLC retention times. Fluorescence labeling by a dansyl group at the N-terminus, or by a W near the CO-terminus, show that up to 12 residues, the peptides were essentially monomeric while longer peptides strongly aggregated in the solution. Lipid affinity was then controlled by peptide length and was found to be limited by folding and self-association in buffer. The lytic activity resulted both from lipid affinity, which varied by a factor of 20-fold, and from efficiency in disturbing the membrane when bound, the latter steeply and monotonously increasing with length. The 15-residue-long peptide, KLLKLLLKLLLKLLK, had the optimal size for highest lytic activity. The shallow location of the fluorescent labels in the lipids is further evidence for a model of peptides remaining flat at the interface. (C) 1999 Elsevier Science B.V. All rights reserved.