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Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
通过18-皇冠-6分子识别质子化基的结构和能量效应
1Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
Journal of the American Chemical Society
|January 14, 2012
概括
这项研究确定了18-crown-6 (18C6) 与质子二相基的结合亲缘关系. 氨酸侧链对18C6具有最高的亲和力,这表明它们是和蛋白质的首选结合点.
科学领域:
- 超分子化学 超分子化学
- 质谱测量质量谱测量
- 计算化学的计算化学
背景情况:
- 18-皇冠-6 (18C6) 是一种循环聚乙烯,以其结合阳离子的能力而闻名.
- 了解18C6与和蛋白质等生物分子的相互作用对于各种应用至关重要.
- 和蛋白质含有基本的氨基酸侧链和一个可以与18C6.6相互作用的N终端氨基群.
研究的目的:
- 量化18C6与各种质子二基的结合亲和关系.
- 为了确定18C6在和蛋白质上首选的结合点.
- 调查18C6复合的不同基础站点之间的潜在竞争.
主要方法:
- 导向离子束双重质谱法 (GIB-MS) 用于实验性地确定绝对的18C6亲和度.
- 理论电子结构计算被用来优化几何形状和计算复合体的能量.
- 研究了九个模仿N端氨基群和基本氨基酸侧链 (Lys,Arg,His) 的质子基.
主要成果:
- 对18-crown-6与氨酸 (Lys) 侧链模仿物的测量结合亲和度大于对氨酸 (Arg) 和氨酸 (His) 侧链模仿物的结合亲和度.
- 在实验中,N端氨基群模仿的结合亲和力与Lys模仿相比或高于Lys模仿,但在理论上较弱.
- 在18C6结合方面,Arg/His和Lys之间的竞争被发现是微不足道的.
结论:
- 氨酸侧链很可能是18-crown-6复合到和蛋白质的主要结合点.
- N端氨基组也可能与lys侧链竞争18C6结合.
- 这些发现提供了对皇冠的和蛋白质分子识别的见解.
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