Effects of charged peptides on electron transfer from [Fe(CN)6]4– to cytochrome c or plastocyanin
Effects of charged peptides on electron transfer from [Fe(CN)6]4– to cytochrome c or plastocyanin
复制标题
带电肽对从 [Fe(CN)6]4– 到细胞色素 c 或质体蓝素的电子转移的影响
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
O. Yamauchi
中科院分区：
文献类型：
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作者：
S. Hirota;M. Endo;T. Tsukazaki;T. Takabe;O. Yamauchi
通过测定[Fe（CN）6]4-与细胞色素c（cyt c）或质体蓝素（PC）之间的电子转移，研究了带电荷的天冬氨酸肽（Aspptds）和赖氨酸肽（Lysptds）与这些肽的相互作用。从Aspptds到penta-aspartic acid，都是[Fe（CN）6]4-向氧化cyt c电子转移的竞争性抑制剂，而Lysptds到penta-lysine，都是促进[Fe（CN）6]4-向氧化PC电子转移的竞争性抑制剂。Aspptds的电子转移抑制作用是通过静电相互作用中和cyt c表面带正电荷的氨基酸残基而产生的竞争性抑制作用，而Lysptds的电子转移促进作用可能是通过形成PC·Lysptd或Lysptd·[Fe（CN）6]4-复合物，随后形成电子转移复合物PC·Lysptd·[Fe（CN）6]4-，而不排斥负电荷。Aspptds的抑制作用和Lysptds的促进作用随着肽的净电荷或浓度的增加而变得显著。Lysptds的促进作用随着PC负补丁的净电荷通过诱变降低而降低。因此，带电荷的肽可以作为探针用于研究蛋白质的分子识别特性。
Abstract Interactions of charged peptides, such as aspartic acid peptides (Aspptds) and lysine peptides (Lysptds), with cytochrome c (cyt c) or plastocyanin (PC) have been studied by measuring electron transfer between [Fe(CN)6]4– and cyt c or PC in the presence of these peptides. Aspptds, up to penta-aspartic acid, served as competitive inhibitors of electron transfer from [Fe(CN)6]4– to oxidized cyt c, while Lysptds, up to penta-lysine, promoted electron transfer from [Fe(CN)6]4– to oxidized PC. The electron transfer inhibitory effects of Aspptds are explained as competitive inhibition due to neutralization of the positively charged amino acid residues at the surface of cyt c by electrostatic interactions, whereas the electron transfer promoting effects of Lysptds may be due to formation of PC·Lysptd or Lysptd·[Fe(CN)6]4– complexes subsequently forming an electron transferring complex, PC·Lysptd·[Fe(CN)6]4–, without repulsion of the negative charges. The inhibitory effect of Aspptds and promotional effect of Lysptds became significant as the net charge or concentration of the peptides increased. The promotional effects of Lysptds decreased as the net charge of the PC negative patch was decreased by mutagenesis. Thus, charged peptides may serve as a probe for investigation of the molecular recognition character of proteins.