NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c3.
NMR studies of electron transfer mechanisms in a protein with interacting redox centres: Desulfovibrio gigas cytochrome c3.
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核磁共振研究具有相互作用的氧化还原中心的蛋白质中的电子转移机制：Desulfovibrio gigas 细胞色素 c3。
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发表时间：
1984
期刊：
影响因子：
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通讯作者：
A. V. Xavier
中科院分区：
文献类型：
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作者：
H. Santos;J. Moura;I. Moura;J. Legall;A. V. Xavier
在改变 pH 值和氧化还原电位的同时，对来自 Desulfovibrio gigas 的四血红素细胞色素 c3 的质子 NMR 谱进行了检查。 NMR 再氧化模式的分析基于四个血红素之间的电子分布模型，该模型考虑了血红素-血红素氧化还原相互作用。分子内电子交换在 NMR 时间尺度上很快（大于 10(5) s-1）。关于不同氧化步骤中血红素甲基共振化学位移和共振强度的 pH 依赖性的 NMR 数据与非相互作用模型不兼容，并且可以通过假设血红素之间的氧化还原相互作用来解释。 pH* = 7.2 和 9.6 时的完整分析表明，血红素-血红素相互作用电位的范围为 -50 mV 至 +60 mV。一些血红素的中点氧化还原电位以及它们的一些相互作用电位取决于 pH 值。讨论了溶液的 pH 值和氧化还原电位调节血红素中点氧化还原电位的生理相关性。
The proton NMR spectra of the tetrahaem cytochrome c3 from Desulfovibrio gigas were examined while varying the pH and the redox potential. The analysis of the NMR reoxidation pattern was based on a model for the electron distribution between the four haems that takes into account haem-haem redox interactions. The intramolecular electron exchange is fast on the NMR time scale (larger than 10(5) s-1). The NMR data concerning the pH dependence of the chemical shift of haem methyl resonances in different oxidation steps and resonance intensities are not compatible with a non-interacting model and can be explained assuming a redox interaction between the haems. A complete analysis at pH* = 7.2 and 9.6, shows that the haem-haem interacting potentials cover a range from -50 mV to +60 mV. The midpoint redox potentials of some of the haems, as well as some of their interacting potentials, are pH-dependent. The physiological relevance of the modulation of the haem midpoint redox potentials by both the pH and the redox potential of the solution is discussed.