β-Peptides: Synthesis by Arndt-Eistert homologation with concomitant peptide coupling. Structure determination by NMR and CD spectroscopy and by X-ray crystallography. Helical secondary structure of a β-hexapeptide in solution and its stability towards pe
作者:Dieter Seebach、Mark Overhand、Florian N. M. Kühnle、Bruno Martinoni、Lukas Oberer、Ulrich Hommel、Hans Widmer
DOI:10.1002/hlca.19960790402
日期:1996.6.26
The β-hexapeptide (H-β-HVal-β-HAla-β-HLeu)2-OH (2) was prepared from the component L-β-amino acids by conventional peptide synthesis, including fragment coupling. A cyclo-β-tri- and a cyclo-β-hexapeptide were also prepared. The β-amino acids were obtained from α-amino acids by Arndt-Eistert homologation. All reactions leading to the β-peptides occur smoothly and in high yields. The β-peptides were
通过常规肽合成,包括片段偶联,由组分L-β-氨基酸制备β-六肽(H-β-HVal-β-HAla-β-HLeu)2 -OH(2)。还制备了环-β-三-和环-β-六肽。β-氨基酸是通过Arndt-Eistert同源从α-氨基酸获得的。导致β肽的所有反应均平稳且高产率地进行。β肽的特征在于其CD和NMR光谱(COSY,ROESY,TOCSY和NOE限制建模),以及X射线晶体结构分析。β-Sheet型结构(固态)和紧凑的左手或(M)3 1发现了5Å螺距的螺旋(在溶液中)。与α-肽的类似二级结构的比较显示出基本的差异,在这一点上最令人惊讶的是β-肽螺旋的更大的稳定性。β-肽与β-羟基链烷酸的低聚物之间存在结构关系,两类化合物之间的差异证明了氢键的作用。β-六肽2在37° C的H 2 O中在pH 2的胃蛋白酶中稳定裂解至少60小时,而相应的α-肽H-(Val-Ala-Leu)2 -OH在这些条件下瞬间裂解。情况。讨论了所描述结果的含义。