His548/His505质子化状态对葡萄糖氧化酶还原半反应的调控
首发时间:2021-05-14
摘要:GOx能够在温和的条件下催化氧化β-D-葡萄糖,直接将生物能转化成电能,在电化学领域具有巨大的应用潜力。GOx常作为酶生物燃料电池(EBFC)的阳极催化剂,以提高EBFC的性能。近年来,在GOx活性中心催化氧化β-D-葡萄糖作用机理的研究中都突出了His505和His548的重要作用,但仍缺乏His505和His548作用机理的系统研究。因此,本论文主要采用ONIOM方法,考察了His548/His505不同质子化状态下的GOx活性中心催化氧化β-D-葡萄糖模型。研究表明,质子化His505/His548不仅能够显著影响β-D-葡萄糖上的质子电子转移,并能于Arg210协同调控质子电子转移。质子化His505能够有效促进β-d-葡萄糖上的两个质子转移,并与Arg210吸电子作用产生协同效应,共同促进GOx活性中心催化反应过程的质子/电子转移,从而有效降低反应活化能。而质子化His548与Arg210分别从相反方向对异咯嗪产生静电吸引作用,不利于GOx活性中心催化反应过程的电子转移。
关键词: 酶生物燃料电池 葡萄糖氧化酶 环境调控 质子耦合电子转移
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Regulation of protonated state of His548/His505 on reductive half-reaction of glucose oxidase
Abstract:Glucose oxidase (GOx) can catalyze the oxidation of β-D-glucose in mild conditions to directly convert biological energy into electrical energy, which has great potential in the field of electrochemistry. In enzymatic biofuel cells (EBFC), GOx is often used as an anodic catalyst to improve the performance. In recent years, the important role of His505 and His548 in the catalytic oxidation of β-D-glucose by GOx active center has been highlighted, but there is still a lack of systematic research on the mechanism of action of His505 and His548. Therefore, in this work, the GOx active center protein models under different protonated states of His548/His505 are investigated with ONIOM method. This result shows that protonated His505/His548 can not only significantly affect the proton electron transfer on β-D-glucose, but also co-regulate the proton electron transfer with Arg210. The electrostatic effect of protonated His505 can effectively promote the transfer of two protons on β-D-glucose, and it has a synergistic effect with electron absorption capacity of Arg210, that promotes the proton/electron transfer in the catalytic reaction process of GOx active center. But the electrostatic attraction of the protonated His548 and Arg210 to isoalloxazine from opposite directions, respectively, which is not conducive to the electron transfer in the catalytic reaction process of the active center of GOx.
Keywords: Enzyme biofuel cell, Glucose oxidase, Environmental regulation, Proton-coupled electron transfer
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His548/His505质子化状态对葡萄糖氧化酶还原半反应的调控
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