Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales , Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE) , Universidad de Buenos Aires and CONICET, 1428 Buenos Aires , Argentina.
Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas , Instituto de Biología Molecular y Celular de Rosario (IBR) , Universidad Nacional de Rosario and CONICET, 2000 Rosario , Argentina.
Inorg Chem. 2019 Feb 4;58(3):2149-2157. doi: 10.1021/acs.inorgchem.8b03244. Epub 2019 Jan 15.
Here we report the spectroscopic and electrochemical characterization of three novel chimeric Cu proteins in which either one or the three loops surrounding the metal ions in the Thermus thermophilus protein have been replaced by homologous human and plant sequences while preserving the set of coordinating amino acids. These conservative modifications mimic basic differences between Cu sites from different organisms and allow for fine tuning the energy gap between alternative electronic ground states of Cu. This results in a systematic modulation of thermodynamic and kinetic electron transfer (ET) parameters and in the selection of one of two possible redox-active molecular orbitals, which differ in the ET reorganization energy by a factor of 2. Moreover, the ET mechanism is found to be frictionally controlled, and the modifications introduced into the different chimeras do not affect the frictional activation parameter.
在这里，我们报告了三种新型嵌合 Cu 蛋白的光谱和电化学特性，这些蛋白中，要么是围绕热球菌蛋白中金属离子的一个或三个环被同源的人类和植物序列取代，而保持了一组配位氨基酸。这些保守的修饰模拟了来自不同生物体的 Cu 位点之间的基本差异，并允许微调 Cu 的替代电子基态之间的能隙。这导致热力学和动力学电子转移 (ET) 参数的系统调制，并选择两个可能的氧化还原活性分子轨道之一，它们在 ET 重组能上相差 2 倍。此外，发现 ET 机制受到摩擦控制，并且引入到不同嵌合体中的修饰不会影响摩擦激活参数。
