Single-channel studies on linear gramicidins with altered amino acid sequences. A comparison of phenylalanine, tryptophane, and tyrosine substitutions at positions 1 and 11.
Single-channel studies on linear gramicidins with altered amino acid sequences. A comparison of phenylalanine, tryptophane, and tyrosine substitutions at positions 1 and 11.
复制标题
对氨基酸序列改变的线性短杆菌肽的单通道研究。
DOI：
10.1016/s0006-3495(84)84153-3
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发表时间：
1984
影响因子：
3.4
通讯作者：
Koeppe2nd,RE
中科院分区：
文献类型：
--
作者：
Mazet,JL;Andersen,OS;Koeppe2nd,RE
使用线性短杆菌肽（A、B 和 C）研究了化学结构和跨膜通道通透性特征之间的关系，其中 1 位氨基酸被苯丙氨酸、色氨酸或酪氨酸化学取代。大多数化合物的纯度估计大于 99.99%。这些修饰导致 NaCl 溶液中电导发生大范围的变化：从色氨酸短杆菌肽 A 到酪氨酸短杆菌肽 B 变化六倍。位置 1 的给定氨基酸取代引起的电导变化与位置 11 的不同。当第一个氨基酸是酪氨酸时，观察到 Na+ 亲和力的唯一重要变化。根据不同类似物和缬氨酸短杆菌肽A（可能除了1位上的酪氨酸）的混合物的实验，没有检测到多肽主链结构的主要构象变化，因为所有研究的化合物都可以与缬氨酸短杆菌肽A形成杂化通道。侧链不与渗透离子直接接触。因此，结果可以根据离子通过通道运动的能量分布的修改来解释，这可能是由于侧链偶极子与通道中离子之间的静电相互作用所致。
The relation between chemical structure and permeability characteristics of transmembrane channels has been investigated with the linear gramicidins (A, B, and C), where the amino acid at position 1 was chemically replaced by phenylalanine, tryptophane or tyrosine. The purity of most of the compounds was estimated to be greater than 99.99%. The modifications resulted in a wide range of conductance changes in NaCl solutions: sixfold from tryptophane gramicidin A to tyrosine gramicidin B. The conductance changes induced by a given amino acid substitution at position 1 are not the same as at position 11. The only important change in the Na+ affinity was observed when the first amino acid was tyrosine. No major conformational changes of the polypeptide backbone structure could be detected on the basis of experiments with mixtures of different analogues and valine gramicidin A (except possibly with tyrosine at position 1), as all the compounds investigated could form hybrid channels with valine gramicidin A. The side chains are not in direct contact with the permeating ions. The results were therefore interpreted in terms of modifications of the energy profile for ion movement through the channel, possibly due to an electrostatic interaction between the dipoles of the side chains and ions in the channel.