环肽。VII。含L-脯氨酸和L-亮氨酸的cyl-2非对映体类似物的合成与构象

Cyclic peptides. VII. Synthesis and conformation of diastereomeric analogs of cyl-2 containing L-proline and L-leucine.

作者信息

Yasutake A, Aoyagi H, Kato T, Izumiya N

出版信息

Int J Pept Protein Res. 1980 Feb;15(2):113-21.

Abstract

Two diastereomeric cyclic tetrapeptides with a sequence of cyclo (-D (and L)-Tyr (me)-L-Ile-L-Pro-L-Leu-) (ID and IL) have been synthesized, which are simplified analogs of a phytotoxic peptide Cyl-2, and contain an L-proline and an L-leucine residue in place of an L-pipecolic acid and a 2-amino-8-oxo-9,10-epoxydecanoic acid residue, respectively, in Cyl-2. The cyclization of the H-D-Tyr(Me)-L-Ile-L-Pro-L-Leu-ONSu proceeded smoothly to give ID in excellent yield (50%), but the cyclization of H-L-Tyr(Me)-L-Ile-L-Pro-L-Leu-ONSu gave IL in much lower yield (10%). Based on the results of 1H- and 13C-n.m.r. studies, differential N-methylation and model buildings of ID, the backbone structure of ID has been proposed to be a unique trans-trans-cis-trans conformation, the L-Ile-L-Pro bond being cis.

摘要

已经合成了两种非对映体环状四肽，其序列为环（-D（和L）-酪氨酸（甲基）-L-异亮氨酸-L-脯氨酸-L-亮氨酸-）（ID和IL），它们是植物毒性肽Cyl-2的简化类似物，并且分别含有一个L-脯氨酸和一个L-亮氨酸残基，以取代Cyl-2中的L-哌啶酸和2-氨基-8-氧代-9,10-环氧癸酸残基。H-D-酪氨酸（甲基）-L-异亮氨酸-L-脯氨酸-L-亮氨酸-ONSu的环化反应顺利进行，以优异的产率（50%）得到ID，但H-L-酪氨酸（甲基）-L-异亮氨酸-L-脯氨酸-L-亮氨酸-ONSu的环化反应得到IL的产率要低得多（10%）。基于ID的1H和13C核磁共振研究结果、差异N-甲基化和模型构建，已提出ID的主链结构为独特的反式-反式-顺式-反式构象，L-异亮氨酸-L-脯氨酸键为顺式。