Kamegai J, Kimura S, Imanishi Y
Biophys J. 1986 May;49(5):1101-8. doi: 10.1016/S0006-3495(86)83738-9.
Sequential polypeptide, poly(Leu-Leu-D-Phe-Pro), containing a part of beta-turn sequence in gramicidin S, was synthesized and investigated as a model for ion channels. Sequential peptides, Boc-(Leu-Leu-D-Phe-Pro)n-OBzl1 (n = 1-4), were also synthesized to acquire conformational information about this polypeptide. From the analyses by NMR, CD, and IR measurements, intramolecular hydrogen bonds were found in the sequential peptides with n larger than two and Boc-(Leu-Leu-D-Phe-Pro)3-OBzl was deduced to adopt a 3(10)-helical conformation. Poly(Leu-Leu-D-Phe-Pro) was also suggested to have this conformation. With the addition of this polymer to oxidized cholesterol membrane, current-voltage response across the membrane was observed. Stepwise fluctuation of current was recorded under a positive electric field to support the channel formation. This polymer might form bundles of 3(10)-helices across the bilayer lipid membrane to pass through the ion.
合成了含有短杆菌肽S中部分β-转角序列的连续多肽聚（亮氨酸-亮氨酸-D-苯丙氨酸-脯氨酸），并将其作为离子通道模型进行研究。还合成了连续肽Boc-(亮氨酸-亮氨酸-D-苯丙氨酸-脯氨酸)n-OBzl1（n = 1-4），以获取有关该多肽的构象信息。通过核磁共振、圆二色光谱和红外测量分析发现，n大于2的连续肽中存在分子内氢键，并且推断Boc-(亮氨酸-亮氨酸-D-苯丙氨酸-脯氨酸)3-OBzl呈3(10)-螺旋构象。聚（亮氨酸-亮氨酸-D-苯丙氨酸-脯氨酸）也被认为具有这种构象。将这种聚合物添加到氧化胆固醇膜中时，观察到跨膜的电流-电压响应。在正电场下记录到电流的逐步波动，以支持通道的形成。这种聚合物可能会在双层脂质膜上形成3(10)-螺旋束以通过离子。
