Valensin G, Maccotta A, Gaggelli E, Grzonka Z, Kasprzykowski F, Kozlowski H
Department of Chemistry, University of Siena, Italy.
Eur J Biochem. 1996 Aug 15;240(1):118-24. doi: 10.1111/j.1432-1033.1996.0118h.x.
Several ocytocin analogues were synthesised by substitution of the Pro residue with sarcosine or N-methylalanine, the glutamine residue with threonine and one of the cysteines with 2-mercaptopropionic acid. All the derivatives were investigated by NMR in dimethylsulfoxide solutions and evidence was obtained for similar preferred conformations in the solution free state. All peptides were shown to form complexes with Mn2+ in solution by the strong paramagnetic effects experienced by several proton resonances. Two structures could be determined, one formed by peptides containing threonine and the other by the remaining peptides. The two structures were delineated by molecular modelling using the Mn(2+)-proton distances obtained by NMR as restraints.
通过用肌氨酸或N-甲基丙氨酸取代脯氨酸残基、用苏氨酸取代谷氨酰胺残基以及用2-巯基丙酸取代其中一个半胱氨酸残基，合成了几种催产素类似物。所有衍生物均在二甲亚砜溶液中通过核磁共振进行研究，并获得了在游离溶液状态下具有相似优选构象的证据。通过几个质子共振所经历的强顺磁效应表明，所有肽在溶液中均能与Mn2+形成复合物。可以确定两种结构，一种由含苏氨酸的肽形成，另一种由其余的肽形成。利用核磁共振获得的Mn(2+) - 质子距离作为约束条件，通过分子建模描绘了这两种结构。
