• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Coordination of Trivalent Metal Cations to Peptides: Results from IRMPD Spectroscopy and Theory
【24h】

Coordination of Trivalent Metal Cations to Peptides: Results from IRMPD Spectroscopy and Theory

机译：三价金属阳离子与肽的配位：IRMPD光谱学和理论结果

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

Structures of trivalent lanthanide metal cations La~(3+), Ho~(3+), and Eu~(3+) with deprotonated Ala_n (n = 2-5) or Leu-enk (Tyr-Gly-Gly-Phe-Leu) are investigated with infrared multiple photon dissociation (IRMPD) spectroscopy between 900 and 1850 cm~(-1) and theory. In all of these complexes, a salt bridge is formed in which the metal cation coordinates to the carboxylate group of the peptide, resulting in a limited conformational space and many sharp IRMPD spectral bands. The IRMPD spectra clearly indicate that all carbonyl groups solvate the metal cation in each of the Alan complexes. Due to strong vibrational coupling between the carbonyl groups, a sharp, high-energy amide I band due to in-phase stretching of all of the amide carbonyl groups bound to the metal cation is observed that is separated by ～50 cm~(-1) from a strong, lower-energy amide I band. This extent of carbonyl coupling, which is sometimes observed in condensed-phase peptide and protein IR spectroscopy, has not been reported in IRMPD spectroscopy studies of other cationized peptide complexes. Intense bands due to carbonyl groups not associated with the metal cation are observed for Leu-enk complexes, indicating that a side chain group, such as the Tyr or Phe aromatic ring, prevents complete carbonyl coordination of the metal cation. Substitution of smaller lanthanide cations for La~(3+) in these peptide complexes results only in minor structural changes consistent with the change in metal cation size. These are the first IRMPD spectra reported for lanthanide metal cationized peptides, and comparison to previously reported protonated and alkali metal or alkaline earth metal cationized peptide complexes reveals many trends consistent with the higher charge state of the lanthanide cations.
机译：具有去质子化的Ala_n（n = 2-5）或Leu-enk（Tyr-Gly-Gly-Phe-）的三价镧系金属阳离子La〜（3 +），Ho〜（3+）和Eu〜（3+）的结构Leu）用红外多光子离解（IRMPD）光谱在900和1850 cm〜（-1）之间进行了理论研究。在所有这些复合物中，形成了一个盐桥，其中的金属阳离子与肽的羧酸根基团配位，从而导致有限的构象空间和许多清晰的IRMPD光谱带。 IRMPD光谱清楚地表明，所有羰基均能溶解每个Alan配合物中的金属阳离子。由于羰基之间强烈的振动偶合，观察到与金属阳离子结合的所有酰胺羰基均进行同相拉伸，形成了一条陡峭的高能酰胺I带，其间隔约为〜50 cm〜（-1 ）来自低能酰胺I强带。羰基偶合的这种程度有时会在缩合肽和蛋白质IR光谱中观察到，但在其他阳离子化肽络合物的IRMPD光谱研究中尚未报道。对于Leu-enk配合物，观察到由于羰基不与金属阳离子缔合而产生的强带，表明侧链基团（例如Tyr或Phe芳环）阻止了金属阳离子的完全羰基配位。这些肽复合物中较小的镧系元素阳离子取代La〜（3+）仅导致与金属阳离子大小的变化一致的微小结构变化。这些是报道的镧系金属阳离子化肽的第一个IRMPD光谱，与以前报道的质子化和碱金属或碱土金属阳离子化肽配合物的比较显示出许多与镧系元素阳离子较高电荷态相符的趋势。

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