• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Racemic beta-Sheets as Templates for the Generation of Homochiral (Isotactic) Peptides from Aqueous Solutions of (RS)-Valine or -Leucine N-Carboxy-anhydrides: Relevance to Biochirogenesis
【24h】

Racemic beta-Sheets as Templates for the Generation of Homochiral (Isotactic) Peptides from Aqueous Solutions of (RS)-Valine or -Leucine N-Carboxy-anhydrides: Relevance to Biochirogenesis

机译：外消旋β-Sheets作为模板从（RS）-缬氨酸或-亮氨酸N-羧酸酐水溶液生成同手性（全同立构）肽：与生物手性的相关性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

As part of our program on biochirogenesis of homochiral peptides from racemic precursors, we report the feasibility of obtaining peptides with homochiral sequences composed of up to 25 residues of the same handedness in the polymerization of racemic valine or leucine N-carboxyanhydrides in aqueous solutions, as initiated by amines. The composition of the oligo-peptides was determined by MALDI-TOF mass spectrometry, and the sequences of some of the heterochiral diastereoisomers were studied by MALDI-TOF MS/MS performed on samples in which the S enantiomers of the monomer were tagged with deuterium atoms. The process comprises several steps: 1) a Markov mechanism of asymmetric induction in the early stages of the polymerization yields libraries of racemic oligopeptides enriched with isotactic diastereoisomers, together with oligopeptide sequences containing enantiomeric blocks of homochiral residues; 2) the short peptides self-assemble into racemic colloidal architectures that serve as regio-enantioselective templates in the ensuing process of chain elongation; 3) homochiral residues of the amino acids located at the periphery of these colloidal aggregates exert efficient enantioselection, which results in the formation of long isotactic oligopeptides. The final diastereoisomeric distribution of the peptides depends upon the composition of the templates, which is determined by the concentration of the initiator. The racemic mixtures of isotactic peptides can be desymmetrized by using enantiopure methyl esters of alpha-amino acids as initiators.
机译：作为我们的外消旋前体同手性肽生物手性生成程序的一部分，我们报告了在水溶液中外消旋缬氨酸或亮氨酸N-羧基酸酐聚合过程中，获得具有多达25个相同手性残基的同手性序列的多肽的可行性，例如由胺引发。通过MALDI-TOF质谱法确定寡肽的组成，并通过MALDI-TOF MS / MS研究了一些杂手性非对映异构体的序列，该样品中单体的S对映体带有氘原子标记。该方法包括几个步骤：1）在聚合反应早期的不对称诱导的马尔可夫机理产生富含等规非对映异构体的外消旋寡肽文库，以及含有同手性残基对映体嵌段的寡肽序列。 2）短肽自组装成消旋胶体结构，在随后的链延长过程中用作区域-对映体选择性模板; 3）位于这些胶体聚集体的外围的氨基酸的同手性残基发挥有效的对映体选择，这导致长等规寡肽的形成。肽的最终非对映异构体分布取决于模板的组成，而模板的组成取决于引发剂的浓度。等规肽的外消旋混合物可以通过使用α-氨基酸的对映体纯甲酯作为引发剂来解除对称。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号