Effect of residue insertion on the stability of polyproline‐I and II structures: circular dichroism spectroscopic analyses of block‐type oligo‐prolines (Pro) m ‐Gly/Ala‐(Pro)
Effect of residue insertion on the stability of polyproline‐I and II structures: circular dichroism spectroscopic analyses of block‐type oligo‐prolines (Pro) m ‐Gly/Ala‐(Pro)
复制标题
残基插入对聚脯氨酸-I 和 II 结构稳定性的影响：块型寡聚脯氨酸 (Pro) m -Gly/Ala-(Pro) 的圆二色光谱分析
DOI：
10.1002/pep2.24170
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发表时间：
2020
期刊：
影响因子：
2.4
通讯作者：
Arichi Yuki
中科院分区：
文献类型：
--
作者：
Kakinoki Sachiro;Kitamura Makoto;Noguchi Yuri;Arichi Yuki
用圆二色性（CD）光谱分析了由两个低聚脯氨酸片段序列和一个非脯氨酸连接残基组成的（Pro）m‐Gly/Ala‐（Pro）npeptides的分子构象。在水和三氟乙醇中的CD光谱表明，两个低聚脯氨酸片段被插入的与聚脯氨酸- II无关的残基（PP - II）分隔开。此外，使用构象过渡系统分析了（Pro）m‐Gly/Ala‐（Pro）npeptide在脂肪醇、甲醇（MeOH）和1‐丙醇（1‐PrOH）中从PP‐II过渡到聚脯氨酸‐I （PP‐I）的稳定性。有趣的是，在低聚脯氨酸的中心插入甘氨酸/亚拉氨酸后，PP‐II/PP‐I的转变被抑制；Ala的抑制作用强于Gly。当插入的Ala的位置向C端移动时，（Pro）m‐Gly/Ala‐（Pro）npeptide在1‐PrOH中显示PP‐II/PP‐I跃迁。我们的研究结果证实，即使在MeOH和1‐PrOH中，（Pro）m‐Gly/Ala‐（Pro）npeptide也倾向于形成PP‐II发夹构象。因此，我们的研究结果表明，在富含脯氨酸的肽中，Gly/Ala的插入可以作为PP - II的稳定剂。
The molecular conformation of oligo‐proline peptides composed of two oligo‐proline block sequences and a non‐proline linker residue, designated as (Pro)m‐Gly/Ala‐(Pro)npeptides, was analyzed by circular dichroism (CD) spectroscopy. The CD spectra in water and trifluoroethanol indicated that the two oligo‐proline blocks were separated by an inserted residue independent of polyproline‐II (PP‐II). In addition, the stability of the (Pro)m‐Gly/Ala‐(Pro)npeptides was analyzed using a conformational transition system, during transition from PP‐II to polyproline‐I (PP‐I) in aliphatic alcohols, methanol (MeOH), and 1‐propanol (1‐PrOH). Interestingly, the PP‐II/PP‐I transition was inhibited after a Gly/Ala was inserted at the center of the oligo‐proline; the inhibitory effect of Ala was stronger than that of Gly. When the position of the inserted Ala moved towards the C‐terminal, the (Pro)m‐Gly/Ala‐(Pro)npeptides displayed a PP‐II/PP‐I transition in 1‐PrOH. Our results confirmed that (Pro)m‐Gly/Ala‐(Pro)npeptides prefer to form PP‐II hairpin conformations even in MeOH and 1‐PrOH. Thus, our findings suggest that the insertion of Gly/Ala acts as a stabilizer in PP‐II in proline‐rich peptides.