Direct Electron Transfer to a Metalloenzyme Redox Center Coordinated to a Monolayer-Protected Cluster
Direct Electron Transfer to a Metalloenzyme Redox Center Coordinated to a Monolayer-Protected Cluster
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DOI：
10.1021/ja9026693
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发表时间：
2009-07-29
影响因子：
15
通讯作者：
Schiffrin, David J.
中科院分区：
文献类型：
--
作者：
Abad, Jose M.;Gass, Mhairi;Schiffrin, David J.
本文提出了一种通过连接到单分子层保护金簇的连接体的配位作用，建立与氧化还原金属酶（半乳糖氧化酶，GOase）金属中心电接触的策略。首先在溶液中制备了簇 - 酶杂化体系，并通过高角度环形暗场扫描透射电子显微镜对其进行了表征。通过先用联苯二硫醇自组装单分子层修饰金电极表面，然后与硫辛酸封端的金簇反应，实现了金电极与半乳糖氧化酶之间的电化学通信。然后通过羧酸盐封端的金簇的配位作用取代半乳糖氧化酶CuⅡ外源位点上的H₂O分子，从而固定半乳糖氧化酶。这种化学连接确保了氧化还原中心与电极之间的电接触，从而实现了向蛋白质的无媒介体直接电子转移。杂化体系可应用于生物传感器和生物燃料电池，以及用于电化学研究涉及自由基和电子转移反应的反应催化机制。目前的研究结果可推广到其他金属酶。
A strategy for establishing electrical contact to the metal center of a redox metalloenzyme, galactose oxidase (GOase), by coordination of a linker attached to a monolayer-protected gold cluster is presented. The cluster-enzyme hybrid system was first prepared in solution and characterized by high-angle annular dark-field scanning transmission electron microscopy. Electrochemical communication between a gold electrode and GOase was achieved by first modifying the electrode surface with a biphenyl dithiol self-assembled monolayer followed by reaction with gold clusters capped with thioctic acid. GOase was then immobilized by replacement of the H2O Molecule at the Cull exogenous site by coordination of a carboxylate-terminated gold cluster. This chemical attachment ensured electrical contact between the redox center and the electrode, leading to direct mediatorless electron transfer to the protein. Hybrid systems can find applications in biosensors and biofuel cells and for studying electrochemically the catalytic mechanism of reactions for which free radicals and electron-transfer reactions are involved. The present results can be extended to other metalloenzymes.