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High-Affinity Binding and Direct Electron Transfer to Solid Metals by the Shewanella oneidensis MR-1 Outer Membrane c -type Cytochrome OmcA

2006; American Chemical Society; Volume: 128; Issue: 43 Linguagem: Inglês

10.1021/ja063526d

1943-2984

Yijia Xiong, Liang Shi, Baowei Chen, M. Uljana Mayer, Brian H. Lower, Yuri Y. Londer, Saumyaditya Bose, Michael F. Hochella, James K. Fredrickson, Thomas C. Squier,

Electrochemical sensors and biosensors

The purified outer membrane bacterial protein OmcA binds densely to the surface of hematite (Fe2O3), permitting direct electron transfer to this solid mineral to reduce Fe (III) with an electron flux of about 1013 electrons /cm2/s. In the presence of hematite, there is a substantial increase in the amplitude of internal protein motions that correlate with metal reduction. Binding is highly favorable, with a partition coefficient of approximately 2 × 105 (ΔGo' = −28 kJ/mol), where approximately 1014 OmcA proteins bind per cm2 to the solid metal surface, indicating the utility of using purified OmcA in the construction of a biofuel cell.