Synthesis and conformational studies of peptido-squaramide foldable modules: a new class of turn-mimetic compounds
作者:Luis Martínez、Angel Sampedro、Elena Sanna、Antoni Costa、Carmen Rotger
DOI:10.1039/c2ob06715c
日期:——
The β-turn unit is one of the most important secondary structure elements in proteins. The access to new conformationally controlled foldable modules can afford compounds with interesting bioactivities. Here, we describe a new family of peptido-squaramide foldable modules based on the considerable potential of the squaramide unit as a hydrogen bond donor and acceptor as well as the low rotational barrier of the C–N bond. The conformational analysis by NMR of these modules in chloroform and acetonitrile solution shows that a disecondary squaramide with the 4-aminobutyric acid in one of its substituents can mimic the β-turn structure driven by the formation of an intramolecular hydrogen bonded ten-membered ring. This structure, although flexible, has been successfully combined with dipeptide chains to induce the formation of a hairpin-like structure driven by the formation of several cross-strand intramolecular hydrogen bonds.
β-转角单元是蛋白质中最重要的一种二级结构元素。具有新型构象控制的折叠模块可赋予化合物有趣的生物活性。在此,我们描述了一系列基于方形酰胺单元作为氢键供体和受体的巨大潜力以及碳氮键的低旋转能垒的肽基方形酰胺折叠模块。通过核磁共振对这些模块在氯仿和丙酮腈溶液中的构象分析表明,一种含有4-氨基丁酸作为其取代基之一的双二级方形酰胺可模拟由形成一个分子内氢键的十元环驱动的β-转角结构。尽管该结构具有柔性,但它已成功地与二肽链结合,通过形成多个跨越链的分子内氢键驱动了形成类似发夹的结构。