Convertible electron transfer pathways of cytochrome c at TiO2 quantum electrode
Convertible electron transfer pathways of cytochrome c at TiO2 quantum electrode
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DOI：
10.1039/c2ra01049f
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发表时间：
2012-03
期刊：
影响因子：
3.9
通讯作者：
L. Liu;Ning Wang;Lin Guo
中科院分区：
文献类型：
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作者：
L. Liu;Ning Wang;Lin Guo
在这项工作中，通过简单的无模板湿化学方法合成了具有高均匀性和大规模的生物功能超薄TiO2量子线（约3nm），自组装成扁平电缆状的“堆栈”。在自组装的TiO2纳米线（SA-Nw-TiO2）包覆电极上，细胞色素c （cyt c）发生了快速、可逆（或准可逆）和敏感的电子转移过程，这与SA-Nw-TiO2表面的相对离子强度和水合状态密切相关。在适当水合的SA-Nw-TiO2电极上，在最佳体离子环境下，电子基于cyt - c的有效取向在heme边缘可逆转移。有趣的是，在合适的离子微环境下，可转换电子转移发生在以下三个步骤：电子转移驱动cyt - c的部分展开，电子转移和热力学驱动的再折叠。此外，部分展开的cyt c被证明只存在于准可逆的电子转移过程中，并且在完全水合的SA-Nw-TiO2电极上，电子转移的多步途径可以转化为单步途径。
In this work, biofunctional ultrathin TiO2 quantum wires (about 3 nm), self-assembled into flat-cable-like “stacks”, are synthesized by a simple template-free wet chemical method with high uniformity and on a large scale. On the self-assembled TiO2 nanowire (SA-Nw-TiO2) coated electrode, cytochrome c (cyt c) undergoes a fast, reversible (or quasi-reversible) and sensitive electron transfer process that is closely related to the relative ionic strength and the hydrated state of SA-Nw-TiO2 surface. At the suitably hydrated SA-Nw-TiO2 electrode in an optimum bulk ionic environment, electrons are reversibly transferred at the heme edge on the basis of an effective orientation of cyt c. It is interesting to note that in a suitable ionic microenvironment, a convertible electron transfer occurs in the following three steps: electron transfer driven partial unfolding of cyt c, electron transfer, and thermodynamics driven refolding. In addition, the partially unfolded cyt c was proven to exist only in the quasi-reversible electron transfer process, and the multi-step pathway of electron transfer can be converted into the single-step pathway at the fully hydrated SA-Nw-TiO2 electrode.