Conformational properties of trans Ac-Asn-Pro-Tyr-NHMe and trans Ac-Tyr-Pro-Asn-NHMe in dimethylsulfoxide and in water determined by multinuclear n.m.r. spectroscopy.
Conformational properties of trans Ac-Asn-Pro-Tyr-NHMe and trans Ac-Tyr-Pro-Asn-NHMe in dimethylsulfoxide and in water determined by multinuclear n.m.r. spectroscopy.
复制标题
通过多核核磁共振测定反式 Ac-Asn-Pro-Tyr-NHMe 和反式 Ac-Tyr-Pro-Asn-NHMe 在二甲基亚砜和水中的构象特性。
DOI：
10.1111/j.1399-3011.1986.tb01052.x
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
Scheraga,HA
中科院分区：
文献类型：
--
作者：
Stimson,ER;Meinwald,YC;Montelione,GT;Scheraga,HA
不同核之间的邻位偶联常数提供了一系列含天冬酰胺和酪氨酸的肽在DMSO和H2O中的骨架和侧链构象信息。通过用15 N富集Ac-Asn-Pro-Tyr-NHMe的Tyr，可以区分Tyr的两个侧链β质子的共振。根据这些肽中侧链构象分布对偶联常数进行的分析表明，向Pro ‐ Tyr序列中添加Asn导致构象分布的随机性降低。当与Ac-Asn-NHMe和Ac-Tyr-NHMe的侧链旋转异构体分布相比时，Ac-Asn-Pro-Tyr-NHMe的特定Asn和Tyr侧链构象在二甲亚砜溶液中稳定。在二甲亚砜中稳定Ac-Asn-Pro-Tyr-NHMe的独特Tyr侧链构象的相互作用不存在于Ac-Ala-Pro-Tyr-NHMe中，并且不受向Asn-Pro-Tyr的C末端添加瓦尔-Pro的影响。在水中，还观察到Ac-Asn-Pro-Tyr-NHMe的一个Asn侧链构象的优先稳定化，而Tyr侧链旋转异构体分布与Ac-Tyr-NHMe的相似。Asn侧链和Pro ‐ Tyr ‐ NHMe骨架之间的相互作用先前显示在水中稳定Pro ‐ Tyr处的β-弯曲构象。还提供了Ac-Tyr-Pro-Asn-NHMe的数据，其局部相互作用不会稳定二甲亚砜或水中的特定骨架构象。本文研究的肽的构象在二甲亚砜和水中对27 °和62 °之间的温度相对不敏感。序列Asn-Pro-Tyr和Tyr-Pro-Asn存在于核糖核酸酶A中，这些三肽用作该蛋白质折叠中所涉及的相互作用的模型。
Vicinal coupling constants between various nuclei provide backbone and side‐chain conformational information for a series of asparagine‐ and tyrosine‐containing peptides in DMSO and in H2O. By enriching Tyr of Ac‐Asn‐Pro‐Tyr‐NHMe with15N, it has been possible to distinguish between the resonances of the two side‐chain β protons of Tyr. Analysis of the coupling constants in terms of the distributions of side‐chain conformations in these peptides indicates that the addition of Asn to the Pro‐Tyr sequence leads to a less random conformational distribution. When compared to the side‐chain rotamer distribution of Ac‐Asn‐NHMe and Ac‐Tyr‐NHMe, particular Asn and Tyr side‐chain conformations of Ac‐Asn‐Pro‐Tyr‐NHMe are stabilized in dimethylsulfoxide solution. The interaction(s) which stabilize a unique Tyr side‐chain conformation of Ac‐Asn‐Pro‐Tyr‐NHMe in dimethylsulfoxide are not present in Ac‐Ala‐Pro‐Tyr‐NHMe and are unaffected by the addition of Val‐Pro to theC‐terminus of Asn‐Pro‐Tyr. In water, a preferential stabilization of one Asn side‐chain conformation of Ac‐Asn‐Pro‐Tyr‐NHMe is also observed, while the Tyr side‐chain rotamer distribution is similar to that of Ac‐Tyr‐NHMe. An interaction between the Asn side chain and the Pro‐Tyr‐NHMe backbone was previously shown to stabilize a β‐bend conformation at Pro‐Tyr in water. Data are also presented for Ac‐Tyr‐Pro‐Asn‐NHMe, for which local interactions do not stabilize particular backbone conformations in dimethylsulfoxide or in water. The conformations of the peptides studied here are relatively insensitive to temperatures between 27° and 62°, both in dimethylsulfoxide and in water. The sequences Asn‐Pro‐Tyr and Tyr‐Pro‐Asn occur in ribonuclease A, and these tripeptides serve as models for the interactions involved in the folding of this protein.