Wynants C, Van Binst G, Loosli H R
Int J Pept Protein Res. 1985 Jun;25(6):622-7.
The conformational properties of the somatostatin analogue 201-456 (1) have been studied by high field n.m.r. in DMSO. This analogue is the base structure of nine derivates synthesized by Bauer et al. and shows a very low biological activity, although derived structures such as SMS 201-995 (2) are very potent. Our study has shown an important difference between the most stable conformation of the two compounds: although the beta turn type II' structure at the Phe3-Trp4-Lys5 level is present in both analogues, an important conformational change appears at the cystine bridge. In SMS 201-995 the beta turn/beta sheet conformation is stabilized by the additional amino-acids D-Phe1 and Thr8 (ol) through intramolecular H-bonds.
已通过在二甲亚砜中的高场核磁共振研究了生长抑素类似物201 - 456（1）的构象性质。该类似物是鲍尔等人合成的九种衍生物的基础结构，尽管其衍生结构如SMS 201 - 995（2）具有很强的活性，但它显示出非常低的生物活性。我们的研究表明这两种化合物最稳定构象之间存在重要差异：尽管两种类似物在Phe3 - Trp4 - Lys5水平均存在II'型β转角结构，但在胱氨酸桥处出现了重要的构象变化。在SMS 201 - 995中，β转角/β折叠构象通过额外的氨基酸D - Phe1和Thr8（ol）通过分子内氢键得以稳定。
