Effects of dipole moment, linkers, and chromophores at side chains on long-range electron transfer through helical peptides.
Effects of dipole moment, linkers, and chromophores at side chains on long-range electron transfer through helical peptides.
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DOI：
10.1021/jp051592g
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发表时间：
2005-07
期刊：
影响因子：
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通讯作者：
Jun-ichi Watanabe;T. Morita;S. Kimura
中科院分区：
文献类型：
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作者：
Jun-ichi Watanabe;T. Morita;S. Kimura
将分子末端带有二茂铁基团的十八肽分子自组装到金表面，并利用电化学方法研究了二茂铁基团与金之间的长程电子转移。讨论了螺旋肽的偶极矩、连接肽与金的接头以及侧链引入的发色团对电子转移的影响。在水溶液中的单分子膜的循环伏安法显示，超过40 A的长程电子转移发生沿着的肽分子。计时电流法表明，长程电子转移应归因于跳跃机制与使用酰胺基团作为跳跃网站。通过长肽的电子转移没有显着加速的偶极矩。然而，接头显着影响电子转移取决于它是否是亚甲基链或亚苯基，这表明金和肽之间的局部电子转移应该是最慢的步骤，以确定整体速率。芘基基团引入到肽分子中间的侧链中并没有明显改变电子转移，可能是因为芘基基团距离太远，不允许它们之间的直接电子转移。还计算了跨肽单层的静电势分布，以合理地解释本肽系统中的几个有趣的特征。
Octadecapeptides carrying a ferrocene moiety at the molecular terminal were self-assembled on gold, and long-range electron transfer from the ferrocene moiety to gold was investigated by electrochemical methods. Effects on electron transfer of dipole moment of helical peptides, linkers connecting the peptide to gold, and chromophores introduced into the side chains were discussed. Cyclic voltammetry of the monolayers in an aqueous solution revealed that long-range electron transfer over 40 A occurred along the peptide molecule. Chronoamperometry showed that the long-range electron transfer should be ascribed to a hopping mechanism with use of amide groups as hopping sites. Electron transfer through the long peptide was not significantly accelerated by the dipole moment. However, the linker remarkably affected electron transfer depending on whether it was a methylene chain or a phenylene group, suggesting that local electron transfer between gold and the peptides should be the slowest step to determine the overall rate. Pyrenyl groups introduced into the side chains in the middle of the peptide molecule did not noticeably change electron transfer, probably because pyrenyl groups were too distant to allow direct electron transfer between them. Electrostatic potential profiles across the peptide monolayers were also calculated to explain reasonably the several interesting features in the present peptide systems.