On the stability of polyproline-I and II structures of proline oligopeptides
On the stability of polyproline-I and II structures of proline oligopeptides
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DOI：
10.1007/s00289-004-0317-6
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发表时间：
2005-01-01
期刊：
影响因子：
3.2
通讯作者：
Oka, M
中科院分区：
文献类型：
--
作者：
Kakinoki, S;Hirano, Y;Oka, M
用固相法合成了由13、6和4个脯氨酸残基组成的脯氨酸寡肽。圆二色性光谱表明，脯氨酸寡肽在水和三氟乙醇中形成聚脯氨酸-II螺旋。然而，它表明，由13个Pro残基组成的寡肽显着呈现从聚脯氨酸-II的聚脯氨酸-I螺旋在甲醇和1-丙醇中的构象转变。这一结果是第一个光谱证据表明，脯氨酸寡肽可以形成聚脯氨酸-I螺旋在纯脂肪醇，如甲醇和1-丙醇。还表明，在1-丙醇中形成聚脯氨酸-I螺旋的倾向比在甲醇中更有利，并且链长越长，聚脯氨酸-I螺旋的稳定性越大。构象稳定性的这种链长依赖性也由使用分子力学的理论计算支持。
Proline oligopeptides composed of 13, 6 and 4 Pro residues were synthesized by solid-phase procedure. The circular dichroism spectra showed that the proline oligopeptides form the polyproline-II helix in water and in trifluoroethnol. However, it was shown that the oligopeptide composed of 13 Pro residues remarkably presents conformational transition from the polyproline-II to the polyproline-I helix in methanol and 1-propanol. This result is the first spectrum evidence that proline oligopeptides can form the polyproline-I helix in pure aliphatic alcohol such as methanol and 1-propanol. It was also shown that the propensity forming polyproline-I helix is more favorable in 1-propanol than in methanol, and also that the longer the chain-length is, the greater the stability of the polyproline-I helix is. Such a chain-length dependency of the conformational stability is also supported by the theoretical calculation using molecular mechanics.