...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biophysical Chemistry: An International Journal Devoted to the Physical Chemistry of Biological Phenomena >The influence of the peptide bond on the conformation of amino acids: a theoretical and FT-IR matrix-isolation study of N-acetylproline.
【24h】

The influence of the peptide bond on the conformation of amino acids: a theoretical and FT-IR matrix-isolation study of N-acetylproline.

机译：肽键对氨基酸构象的影响：N-乙酰脯氨酸的理论和FT-IR基质隔离研究。

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

A combined experimental matrix-isolation FT-IR and theoretical study has been performed to investigate the conformational behavior of N-acetylproline. The conformational landscape of N-acetylproline was explored using successively higher computational methods, i.e. HF, DFT(B3LYP) and finally MP2. The exploration resulted in 10 conformations with a relative energy difference smaller than 22 kJ.mol(-1) at the HF/3-21G level of theory. These conformations led to six different conformations after DFT(B3LYP) optimizations. Further optimization at the MP2/6-31++G** level of theory resulted in the same six conformations, all of them with an energy difference smaller than 11.5kJ.mol(-1). One conformation with an intramolecular H-bond was found which was energetically the most favorable conformation. The vibrational and thermodynamical features were calculated using the DFT and MP2 methodologies. In the experimental matrix-isolation FT-IR spectrum, the most stable conformation was dominant and at least two non-H-bonded conformations could be identified. An experimental rotamerization constant between the H-bonded and the other non-H-bonded conformations was estimated and appeared to agree reasonably well with the theoretical MP2 predictions. Some new spectral features of N-acetylproline compared to proline were discovered which might be used to discriminate between the acetylated and non-acetylated form.
机译：已经进行了组合的实验基质隔离FT-IR和理论研究以研究N-乙酰脯氨酸的构象行为。使用连续更高的计算方法，即HF，DFT（B3LYP）和最终MP2，探索了N-乙酰脯氨酸的构象景观。勘探导致10个构象，其具有小于22kJ.mol（-1）的相对能量差，在理论的水平上。这些构象导致DFT（B3LYP）优化后六种不同的构象。在MP2 / 6-31 ++ G **理论水平的进一步优化导致相同的六个构象，所有这些都具有小于11.5kJ.mol（-1）的能量差。发现一种与分子内H键的构象，其具有充满活力的符合性。使用DFT和MP2方法计算振动和热力学特征。在实验基质隔离FT-IR光谱中，最稳定的构象是显性的，并且可以鉴定至少两个非H键合构象。估计H键合和其他非H键合构象之间的实验旋转恒定恒定，并且似乎与理论MP2预测相当良好。发现与脯氨酸相比的N-乙酰脯氨酸的一些新的光谱特征，其可用于区分乙酰化和非乙酰化形式。

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